<PAGE>   1
                                                                   EXHIBIT 10.42


** CONFIDENTIAL INFORMATION OMITTED AND FILED SEPARATELY WITH THE SECURITIES
   AND EXCHANGE COMMISSION



[LOGO]                                       REVOLVING CREDIT LOAN & SECURITY
                                                        AGREEMENT
                                                 (ACCOUNTS AND INVENTORY)

<TABLE>
<CAPTION>
OBLIGOR            NOTE                           AGREEMENT DATE
**                                                DECEMBER 10,1997
<S>          <C>          <C>                <C>          <C>       <C>
CREDIT LIMIT              INTEREST RATE     *B+0.25%       OFFICER   NO./INITIALS
             $1,500,000.00                    8.750%       48711 THOMAS M. HICKS
</TABLE>

                                        *SEE ATTACHED ADDENDUM FOR RATE OPTIONS


                                  INITIAL HERE

    THIS AGREEMENT is entered into on DECEMBER 10, 1997,between COMERICA
BANK-CALIFORNIA ("Bank") as secured party, whose Headquarter Office Is 333 WEST
SANTA CLARA STREET, SAN JOSE, CA and DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.
("Borrower"), a DELAWARE CORPORATION whose sole place of business (if it has
only one), chief executive office (if it has more than one place of business) or
residence (if an individual) is located at 200 N. WESTLAKE BLVD., #202, WESTLAKE
VILLAGE, CA. The parties agree as follows:

1.  DEFINITIONS

        1.1 "Agreement" as used in this Agreement means and includes this
    Revolving Credit Loan & Security Agreement (Accounts and Inventory), any
    concurrent or subsequent rider to this Revolving Credit Loan & Security
    Agreement (Accounts and Inventory) and any extensions, supplements,
    amendments or modifications to this Revolving Credit Loan & Security
    Agreement (Accounts and Inventory) and to any such rider.

        1.2 "Bank Expenses" as used in this Agreement means and includes: all
    costs or expenses required to be paid by Borrower under this Agreement which
    are paid or advanced by Bank; taxes and insurance premiums of every nature
    and kind of Borrower paid by Bank; filing, recording, publication and search
    fees, appraiser fees, auditor fees and costs, and title insurance premiums
    paid or incurred by Bank in connection with Bank's transactions with
    Borrower; costs and expenses incurred by Bank In collecting the Receivables
    (with or without suit) to correct any default or enforce any provision of
    this Agreement, or in gaining possession of, maintaining, handling,
    preserving, storing, shipping, selling, disposing of, preparing for sale
    and/or advertising to sell the Collateral, whether or not a sale is
    consummated; costs and expenses of suit incurred by Bank in enforcing or
    defending this Agreement or any portion hereof, including, but not limited
    to, expenses incurred by Bank in attempting to obtain relief from any stay,
    restraining order, injunction or similar process which prohibits Bank from
    exercising any of its rights or remedies; and attorneys' fees and expenses
    incurred by Bank in advising, structuring, drafting, reviewing, amending,
    terminating, enforcing, defending or concerning this Agreement, or any
    portion hereof or any agreement related hereto, whether or not suit is
    brought. Bank Expenses shall include Bank's in-house legal charges at
    reasonable rates.

        1.3 "Base Rate" as used in this Agreement means that variable rate of
    interest so announced by Bank at its headquarters office in San Jose,
    California as its "Base Rate" from time to time and which serves as the
    basis upon which effective rates of interest are calculated for those loans
    making reference thereto.

        1.4 "Borrower's Books" as used in this Agreement means and includes all
    of the Borrower's books and records including but not limited to: minute
    books; ledgers; records indicating, summarizing or evidencing Borrower's
    assets, liabilities, Receivables, business operations or financial
    condition, and all information relating thereto, computer programs; computer
    disk or tape files; computer printouts; computer runs; and other computer
    prepared information and equipment of any kind.

        1.5 "Borrowing Base" as used in this Agreement means the sum of: (1)
    NINETY percent 90.00 %) of the net amount of Eligible Accounts after
    deducting therefrom all payments, adjustments and credits applicable thereto
    ("Accounts Receivable Borrowing Base); and (2) the amount, if any, of the
    advances against Inventory agreed to be made pursuant to any Inventory Rider
    ("Inventory Borrowing Base"), or other rider, amendment or modification to
    this Agreement, that may now or hereafter be entered into by Bank and
    Borrower.

        1.6 "Cash Flow" as used in this Agreement means, for any applicable
    period of determination, the Net Income (after deduction for income taxes
    and other taxes of such person determined by reference to income or profits
    of such person) for such period, plus, to the extent deducted in computation
    of such Net Income, the amount of depreciation and amortization expense and
    the amount of deferred tax liability during such period, all as determined
    in accordance with GAAP. The applicable period of determination will be N/A
    beginning with the period from ___________to ___________.

        1.7 "Collateral" as used in this Agreement means and includes each and
    all of the following: the Receivables; the Intangibles; the negotiable
    collateral, the Inventory; all money, deposit accounts and all other assets
    of Borrower in which Bank receives a security interest or which hereafter
    come into the possession, custody or control of Bank; and the proceeds of
    any of the foregoing, including, but not limited to, proceeds of insurance
    covering the collateral and any and all Receivables, Intangibles, negotiable
    collateral, Inventory, equipment, money, deposit accounts or other tangible
    and intangible property of borrower resulting from the sale or other
    disposition of the collateral, and the proceeds thereof. Notwithstanding
    anything to the contrary contained herein, collateral shall not include any
    waste or other materials which have been or may be designated as toxic or
    hazardous by Bank.

        1.8 "Credit" as used in this Agreement means all Obligations, except
    those obligations arising pursuant to any other separate contract,
    instrument, note, or other separate agreement which, by its terms, provides
    for a specified interest rate and term.


**CONFIDENTIAL INFORMATION OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
  EXCHANGE COMMISSION

                                       1.

<PAGE>   2

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

        1.9 "Current Assets" as used in this Agreement means, as of any
    applicable date of determination, all cash, nonaffiliated customer
    receivables, United States government securities, claims against the United
    States government, and inventories.

        1.10 "Current Liabilities" as used in this Agreement means, as of any
    applicable date of determination, (i) all liabilities of a person that
    should be classified as current in accordance with GAAP, including without
    limitation any portion of the principal of the Indebtedness classified as
    current, plus (ii) to the extent not otherwise included, all liabilities of
    the Borrower to any of its affiliates whether or not classified as current
    in accordance with GAAP.

        1.11 "Daily Balance" as used in this Agreement means the amount
    determined by taking the amount of the Credit owed at the beginning of a
    given day, adding any new Credit advanced or incurred on such date, and
    subtracting any payments or collections which are deemed to be paid and are
    applied by Bank in reduction of the Credit on that date under the provisions
    of this Agreement.

        1.12 "Eligible Accounts" as used in this Agreement means and includes
    those accounts of Borrower which are due and payable within THIRTY 30)
    days, or less, from the date of invoice, have been validly assigned to Bank
    and strictly comply with all of Borrower's warranties and representations to
    Bank; but Eligible Accounts shall not include the following: (a) accounts
    with respect to which the account debtor is an officer, employee, partner,
    joint venturer or agent of Borrower; (b) accounts with respect to which
    goods are placed on consignment, guaranteed sale or other terms by reason of
    which the payment by the account debtor may be conditional; (c) * accounts
    with respect to which the account debtor not a resident of the United
    States; (d) accounts with respect to which the account debtor is the United
    States or any department, agency or instrumentality of the United States;
    (e) accounts with respect to which the account debtor is any State of the
    United States or any city, county, town, municipality or division thereof;
    (f) accounts with respect to which the account debtor is a subsidiary of,
    related to, affiliated or has common shareholders, officers or directors
    with Borrower; (g) accounts with respect to which Borrower is or may become
    liable to the account debtor for goods sold or services rendered by the
    account debtor to Borrower; (h) accounts not paid by an account debtor
    within ninety (90) days from the date of the invoice; (i) accounts with
    respect to which account debtors dispute liability or make any claim, or
    have any defense, crossclaim, counterclaim, or offset; (j) accounts with
    respect to which any Insolvency Proceeding is filed by or against the
    account debtor, or if an account debtor becomes insolvent, fails or goes out
    of business; and (k) accounts owed by any single account debtor which exceed
    twenty percent (20%) of all of the Eligible Accounts; and (l) accounts with
    a particular account debtor on which over twenty-five percent (25%) of the
    aggregate amount owing is greater than ninety (90) days from the date of the
    invoice. (m) concentration is allowed for the Canadian distributors up to
    $300,000.00. *"Eligible Accounts" to include Canadian sales,

        1.13 "Event of Default" as used in this Agreement means those events
    described in Section 7 contained herein below.

        1.14 "Fixed Charges" as used in this Agreement means and includes, for
    any applicable period of determination, the sum, without duplication, of (a)
    all interest paid or payable during such period by a person on debt of such
    person, plus (b) all payments of principal or other sums paid or payable
    during such period by such person with respect to debt of such person having
    a final maturity more than one year from the date of creation of such debt,
    plus (c) all debt discount and expense amortized or required to be amortized
    during such period by such person, plus (d) the maximum amount of all rents
    and other payments paid or required to be paid by such person during such
    period under any lease or other contract or arrangement providing for use of
    real or personal property in respect of which such person is obligated as a
    lessee, use or obligor, plus (e) all dividends and other distributions paid
    or payable by such person or otherwise accumulating during such period on
    any capital stock of such person, plus (f) all loans or other advances made
    by such person during such period to any Affiliate of such person. The
    applicable period of determination will be N/A, beginning with the period
    from _______________ to ___________.

        1.15 "GAAP" as used in this Agreement means as of any applicable period,
   generally accepted accounting principles in effect during such period.

        1.16 "Insolvency Proceeding" as used in this Agreement means and
    includes any proceeding or case commenced by or against the Borrower, or any
    guarantor of Borrower's Obligations, or any of borrower's account debtors,
    under any provisions of the Bankruptcy Code, as amended, or any other
    bankruptcy or insolvency law, including but not limited to assignments for
    the benefit of creditors, formal or informal moratoriums, composition or
    extensions with some or all creditors, any proceeding seeking a
    reorganization, arrangement or any other relief under the Bankruptcy code,
    as amended, or any other bankruptcy or insolvency law.

        1.17 "Intangibles" as used in this Agreement means and includes all of
    Borrower's present and future general Intangibles and other personal
    property (including, without limitation, any and all rights in any legal
    proceedings, goodwill, patents, trade names, copyrights, trademarks,
    blueprints, drawings, purchase orders, computer programs, computer disks,
    computer tapes, literature, reports, catalogs and deposit accounts) other
    than goods and Receivables, as well as Borrower's Books relating to any of
    the foregoing.

        1.18 "Inventory" as used in this Agreement means and includes all
    present and future inventory in which Borrower has any interest, including,
    but not limited to, goods held by Borrower for sale or lease or to be
    furnished under a contract of service and all of Borrower's present and
    future raw materials, work in process, finished goods, advertising
    materials, and packing and shipping materials, wherever located and any
    documents of title representing any of the above, and any equipment,
    fixtures or other property used in the storing, moving, preserving,
    identifying, accounting for and shipping or preparing for the shipping of
    inventory, and any and all other Items hereafter acquired by Borrower by way
    of substitution,


                                       2.

<PAGE>   3

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    replacement, return, repossession or otherwise, and all additions and
    accessions thereto, and the resulting product or mass, and any documents of
    title respecting any of the above.

        1.19 "Net Income" as used in this Agreement means the net income (or
    loss) of a person for any period determined in accordance with GAAP but
    excluding in any event:

         (a) any gains or losses on the sale or other disposition, not in the
         ordinary course of business, of investments or fixed or capital assets,
         and any taxes on the excluded gains and any tax deductions or credits
         on account on any excluded losses; and

         (b) In the case of the Borrower, net earnings of any Person in which
         Borrower has an ownership interest, unless such net earnings shall have
         actually been received by Borrower in the form of cash distributions.

        1.20 "Judicial Officer or Assignee" as used in this Agreement means and
    includes any trustee, receiver, controller, custodian, assignee for the
    benefit of creditors or any other person or entity having powers or duties
    like or similar to the powers and duties of trustee, receiver, controller,
    custodian or assignee for the benefit of creditors.

        1.21 "Obligations" as used in this Agreement means and includes any and
    all loans, advances, overdrafts, debts, liabilities (including, without
    limitation, any and all amounts charged to Borrower's account pursuant to
    any agreement authorizing Bank to charge Borrower's account), obligations,
    lease payments, guaranties, covenants and duties owing by Borrower to Bank
    of any kind and description whether advanced pursuant to or evidenced by
    this Agreement; by any note or other instrument; or by any other agreement
    between Bank and Borrower and whether or not for the payment of money,
    whether direct or indirect, absolute or contingent, due or to become due,
    now existing or hereafter arising, and including, without limitation, any
    debt, liability or obligation owing from Borrower to others which Bank may
    have obtained by assignment, participation, purchase or otherwise, and
    further including, without limitation, all interest not paid when due and
    all Bank Expenses which Borrower is required to pay or reimburse by this
    Agreement, by law, or otherwise.

        1.22 "Person" or "person" as used in this Agreement means and includes
    any individual, corporation, partnership, joint venture, association, trust,
    unincorporated association, joint stock company, government, municipality,
    political subdivision or agency, or other entity.

        1.23 "Receivables" as used in this Agreement means and includes all
    presently existing and hereafter arising accounts, instruments, documents,
    chattel paper, general intangibles, all other forms of obligations owing to
    Borrower, all of Borrower's rights in, to and under all purchase orders
    heretofore or hereafter received, all moneys due to Borrower under all
    contracts or agreements (whether or not yet earned or due), all merchandise
    returned to or reclaimed by Borrower and the Borrower's books (except minute
    books) relating to any of the foregoing.

        1.24 "Subordinated Debt" as used in this Agreement means indebtedness of
    the Borrower to third parties which has been subordinated to the Obligations
    pursuant to a subordination agreement in form and content satisfactory to
    the Bank.

        1.25 "Subordination Agreement" as used in this Agreement means a
    subordination agreement in form satisfactory to Bank making all present and
    future indebtedness of the Borrower to - N/A subordinate to the Obligations.

        1.26 "Tangible Effective Not Worth" as used in this Agreement means net
    worth as determined in accordance with GAAP consistently applied, increased
    by Subordinated Debt, if any, and decreased by the following: patents,
    licenses, goodwill, subscription lists, organization expenses, trade
    receivables converted to notes, money due from affiliates (including
    officers, directors, subsidiaries and commonly held companies).

        1.27 "Tangible Net Worth" as used in this Agreement means, as of any
    applicable date of determination, the excess of

            a. the net book value of all assets of a person (other than patents,
            patent rights, trademarks, trade names, franchises, copyrights,
            licenses, goodwill, and similar intangible assets) after all
            appropriate deductions in accordance with GAAP (including, without
            limitation, reserves for doubtful receivables, obsolescence,
            depreciation and amortization), over

            b. all Debt of such person.

        1.28 "Total Liabilities" as used in this Agreement means the total of
    all items of indebtedness, obligation or liability which, in accordance with
    GAAP consistently applied, would be included in determining the total
    liabilities of the Borrower as of the date Total Liabilities is to be
    determined, including without limitation (a) all obligations secured by any
    mortgage, pledge, security interest or other lien on property owned or
    acquired, whether or not the obligations secured thereby shall have been
    assumed; (b) all obligations which are capitalized lease obligations; and
    (c) all guaranties, endorsements or other contingent or surety obligations
    with respect to the indebtedness of others, whether or not reflected on the
    balance sheets of the Borrower, including any obligation to furnish funds,
    directly or indirectly through the purchase of goods, supplies, services, or
    by way of stock purchase, capital contribution, advance or loan or any
    obligation to enter into a contract for any of the foregoing.

        1.29 'Working Capital" as used in this Agreement means, as of any
    applicable date of determination, Current Assets less Current Liabilities.


                                       3.

<PAGE>   4
                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

        1.30 Any and all terms used in this Agreement shall be construed and
    defined in accordance with the meaning and definition of such terms under
    and pursuant to the California Uniform Commercial Code (hereinafter referred
    to as the "Code") as amended.

2.  LOAN AND TERMS OF PAYMENT

    For value received, Borrower promises to pay to the order of Bank such
    amount, as provided for below, together with interest, as provided for
    below.

        2.1 Upon the request of Borrower, made at any time and from time to time
    during the term hereof, and so long as no Event of Default has occurred,
    Bank shall lend to Borrower an amount equal to the Borrowing Base; provided,
    however, that in no event shall Bank be obligated to make advances to
    Borrower under this Section 2.1 whenever the Daily Balance exceeds, at any
    time, either the Borrowing Base or the sum of FIVE HUNDRED THOUSAND AND
    NO/100 ($500,000.00), such amount being referred to herein as an
    "Overadvance".

        2.2 Except as hereinbelow provided, the Credit shall bear Interest, on
    the Daily Balance owing, at a rate of 250/1000 (0.250) percentage points per
    annum above the Base Rate (the "Rate").* The Credit shall bear interest,
    from and after the occurrence of an Event of Default and without
    constituting a waiver of any such Event of Default, on the Daily Balance
    owing, at a rate three (3) percentage points per annum above the Rate. All
    interest chargeable under this Agreement that is based upon a per annum
    calculation shall be computed on the basis of a three hundred sixty (360)
    day year for actual days elapsed.

        The Base Rate as of the date of this Agreement is EIGHT AND 250/1000
    (8.250%) per annum. In the event that the Base Rate announced is, from time
    to time hereafter changed, adjustment in the Rate shall be made and based on
    the Base Rate in effect on the date of such change. The Rate, as adjusted,
    shall apply to the Credit until the Base Rate is adjusted again. The minimum
    interest payable by the Borrower under this Agreement shall in no event be
    less than N/A per month. All interest payable by Borrower under the Credit
    shall be due and payable on the first day of each calendar month during the
    term of this Agreement and Bank may, at its option, elect to treat such
    interest and any and all Bank Expenses as advances under the Credit, which
    amounts shall thereupon constitute Obligations and shall thereafter accrue
    interest at the rate applicable to the Credit under the terms of the
    Agreement.

    * See attached addendum for interest rate option

        2.3 Without affecting Borrower's obligation to repay immediately any
    Overadvance in accordance with Section 2.1 hereof, all Overadvances shall
    bear additional interest on the amount thereof at a rate equal to N/A (N/A%)
    percentage points per month in excess of the interest rate set forth in
    Section 2.2, from the date incurred and for each month thereafter, until
    repaid in full.

3.  TERM.

        3.1 This Agreement shall remain in full force and effect until JUNE 1,
    1998, or until terminated by notice by Borrower. Notice of such termination
    by Borrower shall be effectuated by mailing of a registered or certified
    letter not less than thirty (30) days prior to the effective date of such
    termination, addressed to the Bank at the address set forth herein and the
    termination shall be effective as of the date so fixed in such notice.
    Notwithstanding the foregoing, should Borrower be in default of one or more
    of the provisions of this Agreement, Bank may terminate this Agreement at
    any time without notice. Notwithstanding the foregoing, should either Bank
    or Borrower become insolvent or unable to meet its debts as they mature, or
    fail, suspend, or go out of business, the other party shall have the right
    to terminate this Agreement at any time without notice. On the date of
    termination all Obligations shall become immediately due and payable without
    notice or demand; no notice of termination by Borrower shall be effective
    until Borrower shall have paid all Obligations to Bank in full.
    Notwithstanding termination, until all Obligations have been fully
    satisfied, Bank shall retain its security interest in all existing
    Collateral and Collateral arising thereafter, and Borrower shall continue to
    perform all of its Obligations.

        3.2 After termination and when Bank has received payment in full of
    Borrower's Obligations to Bank, Bank shall reassign to Borrower all
    Collateral held by Bank, and shall execute a termination of all security
    agreements and security interests given by Borrower to Bank, upon the
    execution and delivery of mutual general releases.

4.  CREATION OF SECURITY INTEREST

        4.1 Borrower hereby grants to Bank a continuing security interest in all
    presently existing and hereafter arising Collateral in order to secure
    prompt repayment of any and all Obligations owed by Borrower to Bank and in
    order to secure prompt performance by Borrower of each and all of its
    covenants and Obligations under this Agreement and otherwise created. Banks
    security interest in the Collateral shall attach to all Collateral without
    further act on the part of Bank or Borrower. In the event that any
    Collateral, including proceeds, is evidenced by or consists of a letter of
    credit, advice of credit, instrument, money, negotiable documents, chattel
    paper or similar property (collectively, "Negotiable Collateral"), Borrower
    shall, immediately upon receipt thereof, endorse and assign such Negotiable
    Collateral over to Bank and deliver actual physical possession of the
    Negotiable Collateral to Bank.

        4.2 Bank's security interest in Receivables shall attach to all
    Receivables without further act on the part of Bank or Borrower. Upon
    request from Bank, Borrower shall provide Bank with schedules describing all
    Receivables created or acquired by Borrower (including without limitation
    agings listing the names and addresses of, and amounts owing by date by
    account debtors), and shall execute and deliver written assignments of all
    Receivables to Bank all in a form acceptable to Bank, provided, however,
    Borrower's failure to execute and deliver such schedules and/or assignments
    shall not affect or limit Bank's security interest and other rights in and
    to the Receivables. Together with each schedule,

                                       4.

<PAGE>   5


                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    Borrower shall furnish Bank with copies of Borrower's customers' invoices or
    the equivalent, and original shipping or delivery receipts for all
    merchandise sold, and Borrower warrants the genuineness thereof. Bank or
    Bank's designee may notify customers or account debtors of collection costs
    and expenses to Borrower's account but, unless and until Bank does so or
    gives Borrower other written instructions, Borrower shall collect all
    Receivables for Bank, receive in trust all payments thereon as Bank's
    trustee, and, if so requested to do so from Bank, Borrower shall immediately
    deliver said payments to Bank in their original form as received from the
    account debtor and all letters of credit, advices of credit, instruments,
    documents, chattel paper or any similar property evidencing or constituting
    Collateral. Notwithstanding anything to the contrary contained herein, if
    sales of Inventory are made for cash, Borrower shall immediately deliver to
    Bank, in identical form, all such cash, checks, or other forms of payment
    which Borrower receives. The receipt of any check or other item of payment
    by Bank shall not be considered a payment on account until such check or
    other item of payment is honored when presented for payment, in which event,
    said check or other item of payment shall be deemed to have been paid to
    Bank TWO (2) calendar days after the date Bank actually receives such check
    or other item of payment.

        4.3 Bank's security interest in Inventory shall attach to all Inventory
    without further act on the part of Bank or Borrower. Upon Banks request
    Borrower will from time to time at Borrower's expense pledge, assemble and
    deliver such Inventory to Bank or to a third party as Bank's bailee; or hold
    the same in trust for Bank's account or store the same in a warehouse in
    Bank's name; or deliver to Bank documents of title representing said
    Inventory; or evidence of Bank's security interest in some other manner
    acceptable to Bank. Until a default by Borrower under this Agreement or any
    other Agreement between Borrower and Bank, Borrower may, subject to the
    provisions hereof and consistent herewith, sell the Inventory, but only in
    the ordinary course of Borrower's business. A sale of Inventory in
    Borrower's ordinary course of business does not include an exchange or a
    transfer in partial or total satisfaction of a debt owing by Borrower.

        4.4 Borrower shall execute and deliver to Bank concurrently with
    Borrower's execution of this Agreement, and at any time or times hereafter
    at the request of Bank, all financing statements, continuation financing
    statements, security agreements, mortgages, assignments, certificates of
    title, affidavits, reports, notices, schedules of accounts, letters of
    authority and all other documents that Bank may request, in form
    satisfactory to Bank, to perfect and maintain perfected Bank's security
    interest in the Collateral and in order to fully consummate all of the
    transactions contemplated under this Agreement. Borrower hereby irrevocably
    makes, constitutes and appoints Bank (and any of Bank's officers, employees
    or agents designated by Bank) as Borrower's true and lawful attorney-in-fact
    with power to sign the name of Borrower on any financing statements,
    continuation financing statements, security agreement, mortgage, assignment,
    certificate of title, affidavit, letter of authority, notice of other
    similar documents which must be executed and/or filed in order to perfect or
    continue perfected Bank's security interest in the Collateral.

        Borrower shall make appropriate entries in Borrower's Books disclosing
    Bank's security interest in the Receivables. Bank (through any of its
    officers, employees or agents) shall have the right at any time or times
    hereafter during Borrower's usual business hours, or during the usual
    business hours of any third party having control over the records of
    Borrower, to inspect and verify Borrower's Books in order to verify the
    amount or condition of, or any other matter, relating to, said Collateral
    and Borrower's financial condition.

        4.5 Borrower appoints Bank or any other person whom Bank may designate
    as Borrower's attorney-in-fact, with power to endorse Borrower's name on any
    checks, notes, acceptances, money order, drafts or other forms of payment or
    security that may come into Bank's possession; to sign Borrower's name on
    any invoice or bill of lading relating to any Receivables, on drafts against
    account debtors, on schedules and assignments of Receivables, on
    verifications of Receivables and on notices to account debtors; to establish
    a lock box arrangement and/or to notify the post office authorities to
    change the address for delivery of Borrower's mail addressed to Borrower to
    an address designated by Bank, to receive and open all mail addressed to
    Borrower, and to retain all mail relating to the Collateral and forward all
    other mail to Borrower; to send, whether in writing or by telephone,
    requests for verification of Receivables; and to do all things necessary to
    carry out this Agreement. Borrower ratifies and approves all acts of the
    attorney-in-fact. Neither Bank nor its attorney-in-fact will be liable for
    any acts or omissions or for any error of judgment or mistake of fact or
    law. This power being coupled with an interest, is irrevocable so long as
    any Receivables in which Bank has a security interest remain unpaid and
    until the Obligations have been fully satisfied.

        4.6 In order to protect or perfect any security interest which Bank is
    granted hereunder, Bank may, in its sole discretion, discharge any lien or
    encumbrance or bond the same, pay any insurance, maintain guards,
    warehousemen, or any personnel to protect the Collateral, pay any service
    bureau, or, obtain any records, and all costs for the same shall be added to
    the Obligations and shall be payable on demand.

        4.7 Borrower agrees that Bank may provide information relating to this
    Agreement or relating to Borrower to Bank's parent, affiliates, subsidiaries
    and service providers.

5.  CONDITIONS PRECEDENT

        5.1 Conditions precedent to the making of the loans and the extension of
    the financial accommodations hereunder, Borrower shall execute, or cause to
    be executed, and deliver to Bank, in form and substance satisfactory to Bank
    and its counsel, the following:

            a. This Agreement and other documents required by Bank;

            b. Financing statements (Form UCC-1 ) in form satisfactory to Bank
            for filing and recording with the appropriate governmental
            authorities;


                                       5.

<PAGE>   6

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

            c. If Borrower is a corporation, then certified extracts from the
            minutes of the meeting of its board of directors, authorizing the
            borrowings and the granting of the security interest provided for
            herein and authorizing specific officers to execute and deliver the
            agreements provided for herein;

            d. If Borrower is a corporation, then a certificate of good standing
            showing that Borrower is in good standing under the laws of the
            state of its incorporation and certificates indicating that Borrower
            is qualified to transact business and is in good standing in any
            other state in which it conducts business;

            e. If Borrower is a partnership, then a copy of Borrower's
            partnership agreement certified by each general partner of Borrower;

            f. UCC searches, tax lien and litigation searches, fictitious
            business statement filings, insurance certificates, notices or other
            similar documents which Bank may require and in such form as Bank
            may require, in order to reflect, perfect or protect Bank's first
            priority security interest in the Collateral and in order to fully
            consummate all of the transactions contemplated under this
            Agreement;

            g. Evidence that Borrower has obtained insurance and acceptable
            endorsements;

            h. Waivers executed by landlords and mortgagees of any real property
            on which any Collateral is located; and

            i. Warranties and representations of officers.

6.  WARRANTIES REPRESENTATIONS AND COVENANTS.

        6.1 If so requested by Bank, Borrower shall, at such intervals
    designated by Bank, during the term hereof execute and deliver a Report of
    Accounts Receivable or similar report, in form customarily used by Bank.
    Borrower's Borrowing Base at all times pertinent hereto shall not be lose
    than the advances made hereunder. Bank shall have the right to recompute
    Borrower's Borrowing Base in conformity with this Agreement.

        6.2 If any warranty is breached as to any account, or any account is not
    paid in full by an account debtor within NINETY (90) days from the date of
    invoice, or an account debtor disputes liability or makes any claim with
    respect thereto, or a petition in bankruptcy or other application for relief
    under the Bankruptcy Code or any other insolvency law is filed by or against
    an account debtor, or an account debtor makes an assignment for the benefit
    of creditors, becomes insolvent, fails or goes out of business, then Bank
    may deem ineligible any and all accounts owing by that account debtor, and
    reduce Borrower's Borrowing Base by the amount thereof. Bank shall retain
    its security interest in all Receivables and accounts, whether eligible or
    ineligible, until all Obligations have been fully paid and satisfied.
    Returns and allowances, if any, as between Borrower and its customers, will
    be on the same basis and in accordance with the usual customary practices of
    the Borrower, as they exist at this time. Any merchandise which is returned
    by an account debtor or otherwise recovered shall be set aside, marked with
    Bank's name, and Bank shall retain a security interest therein. Borrower
    shall promptly notify Bank of all disputes and claims and settle or adjust
    them on terms approved by Bank. After default by Borrower hereunder, no
    discount, credit or allowance shall be granted to any account debtor by
    Borrower and no return of merchandise shall be accepted by Borrower without
    Bank's consent. Bank may, after default by Borrower, settle or adjust
    disputes and claims directly with account debtors for amounts and upon terms
    which Bank considers advisable, and in such cases Bank will credit
    Borrower's account with only the net amounts received by Bank in payment of
    the accounts, after deducting all Bank Expenses in connection therewith.

        6.3 Borrower warrants, represents, covenants and agrees that:

            a. Borrower has good and marketable title to the Collateral. Bank
            has and shall continue to have a first priority perfected security
            interest in and to the Collateral. The Collateral shall at all times
            remain free and clear of all liens, encumbrances and security
            interests (except those in favor of Bank).

            b. All accounts are and will, at all times pertinent hereto, be bona
            fide existing obligations created by the sale and delivery of
            merchandise or the rendition of services to account debtors in the
            ordinary course of business, free of liens, claims, encumbrances and
            security interests (except as hold by Bank and except as may be
            consented to, in writing, by Bank) and are unconditionally owed to
            Borrower without defenses, disputes, offsets, counterclaims, rights
            of return or cancellation, and Borrower shall have received no
            notice of actual or imminent bankruptcy or insolvency of any account
            debtor at the time an account due from such account debtor is
            assigned to Bank.

            c. At the time each account is assigned to Bank, all property giving
            rise to such account shall have been delivered to the account debtor
            or to the agent for the account debtor for immediate shipment to,
            and unconditional acceptance by, the account debtor. Borrower shall
            deliver to Bank, as Bank may from time to time require, delivery
            receipts, customer's purchase orders, shipping instruction, bills of
            lading and any other evidence of shipping arrangements. Absent such
            a request by Bank, copies of all such documentation shall be held by
            Borrower as custodian for Bank.

        6.4 At the time each eligible account is assigned to Bank, all such
    eligible accounts will be due and payable on terms set forth in Section 1.1
    2, or on such other terms approved in writing by Bank in advance of the
    creation of such accounts and which are expressly set forth on the face of
    all invoices, copies of which shall be held by Borrower as custodian for
    Bank, and no such eligible account will then be past due.

                                       6.

<PAGE>   7

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

        6.5 Borrower shall keep the Inventory only at the following
    locations:_____________________ and the owner or mortgagees of the
    respective locations are:_____________________

        a. Borrower, immediately upon demand by Bank therefor, shall now and
        from time to time hereafter, at such intervals as are requested by Bank,
        deliver to Bank, designations of Inventory specifying Borrower's cost of
        Inventory, the wholesale market value thereof and such other matters and
        information relating to the Inventory as Bank may request;

        b. Borrower's Inventory, valued at the lower of Borrower's cost or the
        wholesale market value thereof, at all times pertinent hereto shall not
        be less than N/A Dollars($    N/A ) of which no less than N/A Dollars
        ($     N/A) shall be in raw materials and finished goods;

        c. All of the Inventory is and shall remain free from all purchase money
        or other security interests, liens or encumbrances, except as held by
        Bank;

        d. Borrower does now keep and hereafter at all times shall keep correct
        and accurate records itemizing and describing the kind, type, quality
        and quantity of the Inventory, its cost therefor and selling price
        thereof, and the daily withdrawals therefrom and additions thereto, all
        of which records shall be available upon demand to any of Bank's
        officers, agents and employees for inspection and copying;

        e. All Inventory, now and hereafter at all times, shall be new Inventory
        of good and merchantable quality free from defects;

        f. Inventory is not now and shall not at any time or times hereafter be
        located or stored with a bailee, warehouseman or other third party
        without Bank's prior written consent, and, in such event, Borrower will
        concurrently therewith cause any such bailee, warehouseman or other
        third party to issue and deliver to Bank, in a form acceptable to Bank,
        warehouse receipts in Bank's name evidencing the storage of Inventory or
        other evidence of Bank's prior rights in the Inventory. In any event,
        Borrower shall instruct any third party to hold all such Inventory for
        Bank's account subject to Bank's security interests and its
        instructions; and

        g. Bank shall have the right upon demand now and/or at all times
        hereafter, during Borrower's usual business hours, to inspect and
        examine the Inventory and to check and test the same as to quality,
        quantity, value and condition and Borrower agrees to reimburse Bank for
        Bank's reasonable costs and expenses in so doing.

        6.6 Borrower represents, warrants and covenants with Bank that Borrower
    will not, without Banks prior written consent:

        a. Grant a security interest in or permit a lien, claim or encumbrance
        upon any of the Collateral to any person, association, firm,
        corporation, entity or governmental agency or instrumentality;

        b. Permit any levy, attachment or restraint to be made affecting any of
        Borrower's assets;

        c. Permit any Judicial Officer or Assignee to be appointed or to take
        possession of any or all of Borrower's assets;

        d. Other than sales of Inventory in the ordinary course of Borrower's
        business, to sell, lease, or otherwise dispose of, move, or transfer,
        whether by sale or otherwise, any of Borrower's assets;

        e. Change its name, business structure, corporate identity or structure;
        add any new fictitious names, liquidate, merge or consolidate with or
        into any other business organization;

        f. Move or relocate any Collateral;

        g. Acquire any other business organization;

        h. Enter into any transaction not in the usual course of Borrower's
        business;

        i. Make any investment in securities of any person, association, firm,
        entity, or corporation other than the securities of the United States of
        America;

        j. Make any change in Borrower's financial structure or in any of its
        business objectives, purposes or operations which would adversely effect
        the ability of Borrower to repay Borrower's Obligations;

        k. Incur any debts outside the ordinary course of Borrower's business
        except renewals or extensions of existing debts and interest thereon;

        l. Make any advance or loan except in the ordinary course of Borrower's
        business as currently conducted;


                                       7.

<PAGE>   8

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

        m. Make loans, advances or extensions of credit to any Person, except
        for sales on open account and otherwise in the ordinary course of
        business;

        n. Guarantee or otherwise, directly or indirectly, in any way be or
        become responsible for obligations of any other Person, whether by
        agreement to purchase the indebtedness of any other Person, agreement
        for the furnishing of funds to any other Person through the furnishing
        of goods, supplies or services, by way of stock purchase, capital
        contribution, advance or loan, for the purpose of paying or discharging
        (or causing the payment or discharge of) the indebtedness of any other
        Person, or otherwise, except for the endorsement of negotiable
        instruments by the Borrower in the ordinary course of business for
        deposit or collection.

        o. (a) Sell, lease, transfer or otherwise dispose of properties and
        assets having an aggregate book value of more than N/A Dollars ($ N/A )
        (whether in one transaction or in a series of transactions) except as to
        the sale of Inventory in the ordinary course of business; (b) change its
        name, consolidate with or merge into any other corporation, permit
        another corporation to merge into it, acquire all or substantially all
        the properties or assets of any other Person, enter into any
        reorganization or recapitalization or reclassify its capital stock, or
        (c) enter into any sale-leaseback transaction;

        p. Subordinate any indebtedness due to it from a person to indebtedness
        of other creditors of such person;

        q. Purchase or hold beneficially any stock or other securities of, or
        make any investment or acquire any interest whatsoever in, any other
        Person, except for the common stock of the Subsidiaries owned by the
        Borrower on the date of this Agreement and except for certificates of
        deposit with maturities of one year or less of United States commercial
        banks with capital, surplus and undivided profits in excess of
        $100,000,000 and direct obligations of the United States Government
        maturing within one year from the date of acquisition thereof; or

        r. Allow any fact, condition or event to occur or exist with respect to
        any employee pension or profit sharing plans established or maintained
        by it which might constitute grounds for termination of any such plan or
        for the court appointment of a trustee to administer any such plan.

        6.7 Borrower is not a merchant whose sales for resale of goods for
    personal, family or household purposes exceeded seventy-five percent (75%)
    in dollar volume of its total sales of all goods during the 12 months
    preceding the filing by Bank of a financing statement describing the
    Collateral. At no time hereafter shall Borrower's sales for resale of goods
    for personal, family or household purposes exceed seventy-five percent (75%)
    in dollar volume of its total sales.

        6.8 Borrower's sole place of business or chief executive office or
    residence is located at the address indicated above and Borrower covenants
    and agrees that it will not, during the term of this Agreement, without
    prior written notification to Bank, relocate said sole place of business or
    chief executive office or residence.

        6.9 If Borrower is a corporation, Borrower represents, warrants and
    covenants as follows:

        a. Borrower will not make any distribution or declare or pay any
        dividend (in stock or in cash) to any shareholder or on any of its
        capital stock, of any class, whether now or hereafter outstanding, or
        purchase, acquire, repurchase, redeem or retire any such capital stock;

        b. Borrower is and shall at all times hereafter be a corporation duly
        organized and existing in good standing under the laws of the state of
        its incorporation and qualified and licensed to do business in
        California or any other state in which it conducts its business;

        c. Borrower has the right and power and is duly authorized to enter into
        this Agreement; and

        d. The execution by Borrower of this Agreement shall not constitute a
        breach of any provision contained in Borrower's articles of
        incorporation or by-laws.

        6.10 The execution of and performance by Borrower of all of the terms
    and provisions contained in this Agreement shall not result in a breach of
    or constitute an event of default under any agreement to which Borrower is
    now or hereafter becomes a party.

        6.11 Borrower shall promptly notify Bank in writing of its acquisition
    by purchase, lease or otherwise of any after acquired property of the type
    included in the Collateral, with the exception of purchases of Inventory in
    the ordinary course of business.

        6.12 All assessments and taxes, whether real, personal or otherwise, due
    or payable by, or imposed, levied or assessed against, Borrower or any of
    its property have been paid, and shall hereafter be paid in full, before
    delinquency. Borrower shall make due and timely payment or deposit of all
    federal, state and local taxes, assessments or contributions required of it
    by law, and will execute and deliver to Bank, on demand, appropriate
    certificates attesting to the payment or deposit thereof. Borrower will make
    timely payment or deposit of all F.I.C.A. payments and withholding taxes
    required of it by applicable laws, and will upon request furnish Bank with
    proof satisfactory to it that Borrower has made such payments or deposit. If
    Borrower fails to pay any such assessment, tax, contribution, or make such
    deposit, or furnish the required proof, Bank may, in its sole and absolute
    discretion and without notice to Borrower,


                                       8.

<PAGE>   9

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    (i) make payment of the same or any part thereof; or (ii) set up such
    reserves in Borrower's account as Bank deems necessary to satisfy the
    liability therefor, or both. Bank may conclusively rely on the usual
    statements of the amount owing or other official statements issued by the
    appropriate governmental agency. Each amount so paid or deposited by Bank
    shall constitute a Bank Expense and an additional advance to Borrower.

        6.13 There are no actions or proceedings pending by or against Borrower
    or any guarantor of Borrower before any court or administrative agency and
    Borrower has no knowledge of any pending, threatened or imminent litigation,
    governmental investigations or claims, complaints, actions or prosecutions
    involving Borrower or any guarantor of Borrower, except as heretofore
    specifically disclosed in writing to Bank. If any of the foregoing arise
    during the term of the Agreement, Borrower shall immediately notify Bank in
    writing.

        6.14 a. Borrower, at its expense, shall keep and maintain its assets
    insured against loss or damage by fire, theft, explosion, sprinklers and all
    other hazards and risks ordinarily insured against by other owners who use
    such properties in similar businesses for the full insurable value thereof.
    Borrower shall also keep and maintain business interruption insurance and
    public liability and property damage insurance relating to Borrower's
    ownership and use of the Collateral and its other assets. All such policies
    of insurance shall be in such form, with such companies, and in such amounts
    as may be satisfactory to Bank. Borrower shall deliver to Bank certified
    copies of such policies of insurance and evidence of the payments of all
    premiums therefor. All such policies of insurance (except those of public
    liability and property damage) shall contain an endorsement in a form
    satisfactory to Bank showing Bank as a loss payee thereof, with a waiver of
    warranties (Form 438-BFU), and all proceeds payable thereunder shall be
    payable to Bank and, upon receipt by Bank, shall be applied on account of
    the Obligations owing to Bank. To secure the payment of the Obligations,
    Borrower grants Bank a security interest in and to all such policies of
    insurance (except those of public liability and property damage) and the
    proceeds thereof, and Borrower shall direct all insurers under such policies
    of insurance to pay all proceeds thereof directly to Bank.

    b. Borrower hereby irrevocably appoints Bank (and any of Bank's officers,
    employees or agents designated by Bank) as Borrower's attorney for the
    purpose of making, selling and adjusting claims under such policies of
    insurance, endorsing the name of Borrower on any check, draft, instrument or
    other item of payment for the proceeds of such policies of insurance and for
    making all determinations and decisions with respect to such policies of
    insurance. Borrower will not cancel any of such policies without Bank's
    prior written consent. Each such insurer shall agree by endorsement upon the
    policy or policies of insurance issued by it to Borrower as required above,
    or by independent instruments furnished to Bank, that it will give Bank at
    least ten (10) days written notice before any such policy or policies of
    insurance shall be altered or cancelled, and that no act or default of
    Borrower, or any other person, shall affect the right of Bank to recover
    under such policy or policies of insurance required above or to pay any
    premium in whole or in part relating thereto. Bank, without waiving or
    releasing any Obligations or any Event of Default, may, but shall have no
    obligation to do so, obtain and maintain such policies of insurance and pay
    such premiums and take any other action with respect to such policies which
    Bank deems advisable. All sums so disbursed by Bank, as well as reasonable
    attorneys' fees, court costs, expenses and other charges relating thereto,
    shall constitute Bank Expenses and are payable on demand.

        6.15 All financial statements and information relating to Borrower which
    have been or may hereafter be delivered by Borrower to Bank are true and
    correct and have been prepared in accordance with GAAP consistently applied
    and there has been no material adverse change in the financial condition of
    Borrower since the submission of such financial information to Bank.

        6.16 a. Borrower at all times hereafter shall maintain a standard and
    modern system of accounting in accordance with GAAP consistently applied
    with ledger and account cards and/or computer tapes and computer disks,
    computer printouts and computer records pertaining to the Collateral which
    contain information as may from time to time be requested by Bank, not
    modify or change its method of accounting or enter into, modify or terminate
    any agreement presently existing, or at any time hereafter entered into with
    any third party accounting firm and/or service bureau for the preparation
    and/or storage of Borrower's accounting records without the written consent
    of Bank first obtained and without said accounting firm and/or service
    bureau agreeing to provide information regarding the Receivables and
    inventory and Borrower's financial condition to Bank; permit Bank and any of
    its employees, officers or agents, upon demand, during Borrower's usual
    business hours, or the usual business hour of third persons having control
    thereof, to have access to and examine all of the Borrower's Book relating
    to the Collateral, Borrower's obligations to Bank, Borrower's financial
    condition and the results of Borrower's operations and in connection
    therewith, permit Bank or any of its agents, employees or officers to copy
    and make extracts therefrom.

INITIAL HERE
[INITIALS]

    b. Borrower shall deliver to Bank within FORTY FIVE (45) days after the end
    of each QUARTER, a  COMPANY PREPARED balance sheet and profit and loss
    statement covering Borrower's operations and deliver to Bank within ninety
    (90) days after the end of each of Borrower's fiscal years a(n)/CPA AUDITED
    statement of the financial condition of the Borrower for each such fiscal
    year, including but not limited to, a balance sheet and profit and loss
    statement and any other report requested by Bank relating to the Collateral
    and the financial condition of Borrower, and a certificate signed by an
    authorized employee of Borrower to the effect that all reports, statements,
    computer disk or tape files, computer printouts, computer runs, or other
    computer prepared information of any kind or nature relating to the
    foregoing or documents delivered or caused to be delivered to Bank under
    this subparagraph are complete, correct and thoroughly present the financial
    condition of borrower and that there exists on the date of delivery to Bank
    no condition or event which constitutes a breach or Event of Default under
    this Agreement.


                                       9.

<PAGE>   10

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    c. In addition to the financial statements requested above, the Borrower
    agrees to provide Bank with the following schedules:

    X   Accounts Receivable Agings  on a  MONTHLY DAYS    basis:
--------                                  ----------------
                                          WITH IN 15 DAYS AFTER THE END OF EACH
                                          MONTH

    X   Accounts Payable Agings     on a  MONTHLY         basis;
--------                                  ----------------
                                          WITHIN 15 DAYS AFTER THE END OF EACH
                                          MONTH
        Job Progress Reports        on a                  basis; and
--------                                  ----------------

    X   BORROWING BASE CERTIFICATE  on a  MONTHLY         basis WITHIN 30 DAYS
--------                                  ----------------
                                          AFTER THE END OF EACH MONTH (IF
                                          COMPANY  DRAWS UNDER THE LINE,
                                          OTHERWISE NO REPORTING IS REQUIRED)

        6.17 Borrower shall maintain the following financial ratios and
    covenants on a consolidated and non-consolidated basis:

    a. Working Capital In an amount not less than N/A


    b. Tangible Effective Net Worth in an amount not less than $6,500,000.00 TO
    INCREASE BY 75% OF QUARTERLY PROFITABILITY AND 100% OF NEW EQUITY OR
    SUBORDINATED DEBT RAISED.

    c. a ratio of Current Assets to Current Liabilities of not less than N/A

    d. a quick ratio of cash plus securities plus Receivables to Current
    Liabilities of not less than 1.5O:1:00.

    e. a ratio of Total Liabilities (less debt subordinated to Bank) to Tangible
    Effective Net Worth of less than 1.00:1.00.

    f. a ratio of Cash Flow to Fixed Charges of not less than N/A

    g. Net Income after taxes of N/A

    h. Borrower shall not without Bank's prior written consent acquire or expend
    for or commit itself to acquire or expend for fixed assets by lease,
    purchase or otherwise in an aggregate amount that exceeds NO/100 n/a Dollars
    ($ n/a 0.00) In any fiscal year; and

    i. SEMI-ANNUAL ACCOUNTS RECEIVABLES AND INVENTORY AUDITS; J. DEBT SERVICE
    COVERAGE ON ROLLING TWO QUARTERS BASIS BEGINNING FROM THE QUARTER ENDING
    JUNE 30, 1998.

        All financial covenants shall be computed in accordance with GAAP
    consistently applied except as otherwise specifically set forth in this
    Agreement. All monies due from affiliates (including officers, directors and
    shareholders) shall be excluded from Borrower's assets for all purposes
    hereunder.

        6.18 Borrower shall promptly supply Bank (and cause any guarantor to
    supply Bank) with such other information (including tax returns) concerning
    its financial affairs (or that of any guarantor) as Bank may request from
    time to time hereafter, and shall promptly notify Bank of any material
    adverse change in Borrower's financial condition and of any condition or
    event which constitutes a breach of or an event which constitutes an Event
    of Default under this Agreement.

        6.19 Borrower is now and shall be at all times hereafter solvent and
    able to pay its debts (including trade debts) as they mature.

        6.20 Borrower shall immediately and without demand reimburse Bank for
    all sums expended by Bank in connection with any action brought by Bank to
    correct any default or enforce any provision of this Agreement, including
    all Bank Expenses; Borrower authorizes and approves all advances and
    payments by Bank for items described in this Agreement as Bank Expenses.

        6.21 Each warranty, representation and agreement contained in this
    Agreement shall be automatically deemed repeated with each advance and shall
    be conclusively presumed to have been relied on by Bank regardless of any
    investigation made or information possessed by Bank. The warranties,
    representations and agreements set forth herein shall be cumulative and in
    addition to any and all other warranties, representations and agreements
    which Borrower shall give, or cause to be given, to Bank, either now or
    hereafter.

        6 .22 Borrower shall keep all of its principal bank accounts with Bank
    and shall notify the Bank immediately in writing of the existence of any
    other bank account, deposit account, or any other account into which money
    can be deposited.

        6.23 Borrower shall furnish to the Bank: (a) as soon as possible, but in
    no event later than thirty (30) days after Borrower knows or has reason to
    know that any reportable event with respect to any deferred compensation
    plan has occurred, a statement of the chief financial officer of Borrower
    setting forth the details concerning such reportable

                                       10.

<PAGE>   11

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    event and the action which Borrower proposes to take with respect thereto,
    together with a copy of the notice of such reportable event given to the
    Pension Benefit Guaranty Corporation, if a copy of such notice is available
    to Borrower, (b) promptly after the filing thereof with the United States
    Secretary of Labor or the Pension Benefit Guaranty Corporation, copies of
    each annual report with respect to each deferred compensation plan; (c)
    promptly after receipt thereof, a copy of any notice Borrower may receive
    from the Pension Benefit Guaranty Corporation or the Internal Revenue
    Service with respect to any deferred compensation plan; provided, however,
    this subparagraph shall not apply to notice of general application issued by
    the Pension Benefit Guaranty Corporation or the Internal Revenue Service;
    and (d) when the same is made available to participants in the deferred
    compensation plan, all notices and other forms of information from time to
    time disseminated to the participants by the administrator of the deferred
    compensation plan.

        6.24 Borrower is now and shall at all times hereafter remain in
    compliance with all federal, state and municipal laws, regulations and
    ordinances relating to the handling, treatment and disposal of toxic
    substances, wastes and hazardous material and shall maintain all necessary
    authorizations and permits.

        6.25 Borrower shall maintain insurance on the life of N/A in an amount
    not to be less than NO/100 Dollars ($ N/A) under one more policies issued by
    insurance companies satisfactory to Bank, which policies shall be assigned
    to Bank as security for the Obligations and on which Bank shall be named as
    sole beneficiary.

        6.26 Borrower shall limit direct and indirect compensation paid to the
    following employees: N/A, to an aggregate of N/A Dollars ($ N/A) per N/A.

7.  EVENTS OF DEFAULT.

    Any one or more of the following events shall constitute a default by
    Borrower under this Agreement:

    a. If Borrower fails or neglects to perform, keep or observe any term,
    provision, condition, covenant, agreement, warranty or representation
    contained in this Agreement, or any other present or future agreement
    between Borrower and Bank;

    b. If any representation, statement, report or certificate made or delivered
    by Borrower, or any of its officers, employees or agents to Bank is not true
    and correct;

    c. If Borrower fails to pay when due and payable or declared due and
    payable, all or any portion of the Borrower's Obligations (whether of
    principal, interest, taxes, reimbursement of Bank Expenses, or otherwise);

    d. If there is a material impairment of the prospect of repayment of all or
    any portion of Borrower's Obligations or a material impairment of the value
    or priority of Bank's security interest in the Collateral;

    e. If all or any of Borrower's assets are attached, seized, subject to a
    writ or distress warrant, or are levied upon, or come into the possession of
    any Judicial Officer or Assignee and the same are not released, discharged
    or bonded against within ten (10) days thereafter;

    f. If any Insolvency Proceeding is filed or commenced by or against Borrower
    without being dismissed within ten (10) days thereafter;

    g. If any proceeding is filed or commenced by or against Borrower for its
    dissolution or liquidation;

    h. If Borrower is enjoined, restrained or in any way prevented by court
    order from continuing to conduct all or any material part of its business
    affairs;

    i. If a notice of lien, levy or assessment is filed of record with respect
    to any or all of Borrower's assets by the United States Government, or any
    department, agency or instrumentality thereof, or by any state, county,
    municipal or other government agency, or if any taxes or debts owing at any
    time hereafter to any one or more of such entities becomes a lien, whether
    choate or otherwise, upon any or all of the Borrower's assets and the same
    is not paid on the payment date thereof;

    j. If a judgment or other claim becomes a lien or encumbrance upon any or
    all of Borrower's assets and the same is not satisfied, dismissed or bonded
    against within ten (10) days thereafter;

    k. If Borrower's records are prepared and kept by an outside computer
    service bureau at the time this Agreement is entered into or during the term
    of this Agreement such an agreement with an outside service bureau is
    entered into, and at any time thereafter, without first obtaining the
    written consent of Bank, Borrower terminates, modifies, amends or changes
    its contractual relationship with said computer service bureau or said
    computer service bureau fails to provide Bank with any requested information
    or financial data pertaining to Bank's Collateral, Borrower's financial
    condition or the results of Borrower's operations;

    1. If Borrower permits a default in any material agreement to which Borrower
    is a party with third parties so as to result in an acceleration of the
    maturity of Borrower's indebtedness to others, whether under any indenture,
    agreement or otherwise;

                                       11.

<PAGE>   12

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    m. If Borrower makes any payment on account of indebtedness which has been
    subordinated to Borrower's Obligations to Bank;

    n. If any misrepresentation exists now or thereafter in any warranty or
    representation made to Bank by any officer or director of Borrower, or if
    any such warranty or representation is withdrawn by any officer or director;

    o. If any party subordinating its claims to that of Bank's or any guarantor
    of Borrower's Obligations dies or terminates its subordination or guaranty,
    becomes insolvent or an Insolvency Proceeding is commenced by or against any
    such subordinating party or guarantor;

    p. If Borrower is an individual and Borrower dies;

    q. If there is a change of ownership or control of N/A percent (%) or more
    of the issued and outstanding stock of Borrower; or

    r. If any reportable event, which the Bank determines constitutes grounds
    for the termination of any deferred compensation plan by the Pension Benefit
    Guaranty Corporation or for the appointment by the appropriate United States
    District Court of a trustee to administer any such plan, shall have occurred
    and be continuing thirty (30) days after written notice of such
    determination shall have been given to Borrower by Bank, or any such Plan
    shall be terminated within the meaning of Title IV of the Employment
    Retirement Income Security Act ("ERISA"), or a trustee shall be appointed by
    the appropriate United States District Court to administer any such plan, or
    the Pension Benefit Guaranty Corporation shall institute proceedings to
    terminate any plan and in case of any event described in this Section 7.0,
    the aggregate amount of the Borrower's liability to the Pension Benefit
    Guaranty Corporation under Sections 4062, 4063 or 4064 of ERISA shall exceed
    five percent (5%) of Borrower's Tangible Effective Net Worth.

    Notwithstanding anything contained in Section 7 to the contrary, Bank shall
    refrain from exercising its rights and remedies and Event of Default shall
    thereafter not be deemed to have occurred by reason of the occurrence of any
    of the events set forth in Sections 7.e, 7.f or 7.j of this Agreement if,
    within ten (10) days from the date thereof, the same is released,
    discharged, dismissed, bonded against or satisfied; provided, however, if
    the event is the institution of insolvency Proceedings against Borrower,
    Bank shall not be obligated to make advances to Borrower during such cure
    period.

8.  BANK'S RIGHTS AND REMEDIES.

        8.1 Upon the occurrence of an Event of Default by Borrower under this
    Agreement, Bank may, at its election, without notice of its election and
    without demand, do any one or more of the following, all of which are
    authorized by Borrower:

        a. Declare Borrower's Obligations, whether evidenced by this Agreement,
        installment notes, demand notes or otherwise, immediately due and
        payable to the Bank;

        b. Cease advancing money or extending credit to or for the benefit of
        Borrower under this Agreement, or any other agreement between Borrower
        and Bank;

        c. Terminate this Agreement as to any future liability or obligation of
        Bank, but without affecting Bank's rights and security interests in the
        Collateral, and the Obligations of Borrower to Bank;

        d. Without notice to or demand upon Borrower or any guarantor, make such
        payments and do such acts as Bank considers necessary or reasonable to
        protect its security interest in the Collateral. Borrower agrees to
        assemble the Collateral if Bank so requires and to make the Collateral
        available to Bank as Bank may designate. Borrower authorizes Bank to
        enter the premises where the Collateral is located, take and maintain
        possession of the Collateral and the premises (at no charge to Bank), or
        any part thereof, and to pay, purchase, contest or compromise any
        encumbrance, charge or lien which in the opinion of Bank appears to be
        prior or superior to its security interest and to pay all expenses
        incurred in connection therewith;

        e. Without limiting Bank's rights under any security interest, Bank is
        hereby granted a license or other right to use, without charge,
        Borrower's labels, patents, copyrights, rights of use of any name, trade
        secrets, trade names, trademarks and advertising matter, or any property
        of a similar nature as it pertains to the Collateral, in completing
        production of, advertising for sale and selling any Collateral and
        Borrower's rights under all licenses and all franchise agreement shall
        inure to Bank's benefit, and Bank shall have the right and power to
        enter into sublicense agreements with respect to all such rights with
        third parties on terms acceptable to Bank;

        f. Ship, reclaim, recover, store, finish, maintain, repair, prepare for
        sale, advertise for sales and sell (in the manner provided for herein)
        the inventory;

        g. Sell or dispose the Collateral at either a public or private sale, or
        both, by way of one or more contracts or transactions, for cash or on
        terms, in such manner and at such places (including Borrower's premises)
        as is commercially reasonable in the opinion of Bank. It is not
        necessary that the Collateral be present at any such sale;

        h. Bank shall give notice of the disposition of the Collateral as
        follows:

                                       12.

<PAGE>   13

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

            (1) Bank shall give the Borrower and each holder of a security
            interest in the Collateral who has filed with Bank a written request
            for notice, a notice in writing of the time and place of public
            sale, or, if the sale is a private sale or some disposition other
            than a public sale is to be made of the Collateral, the time on or
            after which the private sale or other disposition is to be made;

            (2) The notice shall be personally delivered or mailed, postage
            prepaid, to Borrower's address appearing in this Agreement, at least
            five (5) calendar days before the date fixed for the sale, or at
            least five (5) calendar days before the date on or after which the
            private sale or other disposition is to be made, unless the
            Collateral is perishable or threatens to decline speedily in value.
            Notice to persons other than Borrower claiming an interest in the
            Collateral shall be sent to such addresses as they have furnished to
            Bank;

            (3) If the sale is to be a public sale, Bank shall also give notice
            of the time and place by publishing a notice one time at least five
            (5) calendar days before the date of the sale in a newspaper of
            general circulation in the county in which the sale is to be held;
            and

            (4) Bank may credit bid and purchase at any public sale.

        i. Borrower shall pay all Bank Expenses incurred in connection with
        Bank's enforcement and exercise of any of its rights and remedies as
        herein provided, whether or not suit is commenced by Bank;

        j. Any deficiency which exists after disposition of the Collateral as
        provided above will be paid immediately by Borrower. Any excess will be
        returned, without interest and subject to the rights of third parties,
        to Borrower by Bank, or, in Bank's discretion, to any party who Bank
        believes, in good faith, is entitled to the excess; and

        k. Without constituting a retention of Collateral in satisfaction of an
        obligation within the meaning of 9505 of the Uniform Commercial Code or
        an action under California Code of Civil Procedure 726, apply any and
        all amounts maintained by Borrower as deposit accounts (as that term is
        defined under 91 05 of the Uniform Commercial Code) or other accounts
        that Borrower maintains with Bank against the Obligations.

        8.2 Bank's rights and remedies under this Agreement and all other
    agreements shall be cumulative. Bank shall have all other rights and
    remedies not inconsistent herewith as provided by law or in equity. No
    exercise by Bank of one right or remedy shall be deemed an election, and no
    waiver by Bank of any default on Borrower's part shall be deemed a
    continuing waiver. No delay by Bank shall constitute a waiver, election or
    acquiescence by Bank.

9.  TAXES AND EXPENSES REGARDING BORROWER'S PROPERTY.

If Borrower fails to pay promptly when due to another person or entity, monies
which Borrower is required to pay by reason of any provision in this Agreement,
Bank may, but need not, pay the same and charge Borrower's account therefor, and
Borrower shall promptly reimburse Bank. All such sums shall become additional
indebtedness owing to Bank, shall bear interest at the rate hereinabove
provided, and shall be secured by all Collateral. Any payments made by Bank
shall not constitute (i) an agreement by it to make similar payments in the
future; or (ii) a waiver by Bank of any default under this Agreement. Bank need
not inquire as to, or contest the validity of, any such expense, tax, security
interest, encumbrance or lien and the receipt of the usual official notice of
the payment thereof shall be conclusive evidence that the same was validly due
and owing. Such payments shall constitute Bank Expenses and additional advances
to Borrower.

10. WAIVERS.

        10.1 Borrower agrees that checks and other instruments received by Bank
    in payment or on account of Borrower's Obligations constitute only
    conditional payment until such items are actually paid to Bank and Borrower
    waives the right to direct the application of any and all payments at any
    time or times hereafter received by Bank on account of Borrower's
    Obligations and Borrower agrees that Bank shall have the continuing
    exclusive right to apply and reapply such payments in any manner as Bank may
    deem advisable, notwithstanding any entry by Bank upon its books.

        10.2 Borrower waives demand, protest, notice of protest, notice of
    default or dishonor, notice of payment and nonpayment, notice of any
    default, nonpayment at maturity, release, compromise, settlement, extension
    or renewal of any or all commercial paper, accounts, documents, instruments
    chattel paper, and guarantees at any time held by Bank on which Borrower may
    in any way be liable.

        10.3 Bank shall not in any way or manner be liable or responsible for
    (a) the safekeeping of the Inventory; (b) any loss or damage thereto
    occurring or arising in any manner or fashion from any cause; (c) any
    diminution in the value thereof; or (d) any act or default of any carrier,
    warehouseman, bailee, forwarding agency or other person whomsoever. All risk
    of loss, damage or destruction of Inventory shall be borne by Borrower.

        10.4 Borrower waives the right and the right to assert a confidential
    relationship, if any, it may have with any accountant, accounting firm
    and/or service bureau or consultant in connection with any information
    requested by Bank pursuant to or in accordance with this Agreement, and
    agrees that a Bank may contact directly any such accountants, accounting
    firm and/or service bureau or consultant in order to obtain such
    information.

        l0.5 BORROWER AND BANK EACH WAIVE ANY RIGHT TO TRIAL BY JURY IN ANY
    ACTION OR PROCEEDING RELATING TO THIS AGREEMENT OR ANY TRANSACTION
    HEREUNDER, OR CONTEMPLATED HEREUNDER, OR ANY OTHER CLAIM (INCLUDING TORT OR
    BREACH OF DUTY CLAIMS) OR DISPUTE HOWSOEVER ARISING BETWEEN BANK AND
    BORROWER.


                                       13.

<PAGE>   14
                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

    10.6 In the event that Bank elects to waive any rights or remedies
    hereunder, or compliance with any of the terms hereof, or delays or fails to
    pursue or enforce any terms, such waiver, delay or failure to pursue or
    enforce shall only be effective with respect to that single act and shall
    not be construed to affect any subsequent transactions or Bank's right to
    later pursue such rights and remedies.

11. ONE CONTINUING LOAN TRANSACTION.

   All loans and advances heretofore, now or at any time or times hereafter made
   by Bank to Borrower under this Agreement or any other agreement between Bank
   and Borrower, shall constitute one loan secured by Bank's security interests
   in the Collateral and by all other security interests, liens, encumbrances
   heretofore, now or from time to time hereafter granted by Borrower to Bank.

   Notwithstanding the above, (i) to the extent that any portion of the
   Obligations are a consumer loan, that portion shall not be secured by any
   deed of trust or mortgage on or other security interest in the Borrower's
   principal dwelling which is not a purchase money security interest as to that
   portion, unless expressly provided to the contrary in another place, or (ii)
   if the Borrower (or any of them) has (have) given or give(s) Bank a deed of
   trust or mortgage covering real property, that deed of trust or mortgage
   shall not secure the loan and any other Obligation of the Borrower (or any of
   them), unless expressly provided to the contrary in another place.

12. NOTICES.

   Unless otherwise provided in this Agreement, all notices or demands by either
   party on the other relating to this Agreement shall be in writing and sent by
   regular United States mail, postage prepaid, properly addressed to Borrower
   or to Bank at the addresses stated in this Agreement, or to such other
   addresses as Borrower or Bank may from time to time specify to the other in
   writing. Requests to Borrower by Bank hereunder may be made orally.

13. AUTHORIZATION TO DISBURSE.

   Bank is hereby authorized to make loans and advances hereunder upon
   telephonic or other instructions received from anyone purporting to be an
   officer, employee, or representative of Borrower, or at the discretion of
   Bank if said loans and advances are necessary to meet any Obligations of
   Borrower to Bank. Bank shall have no duty to make inquiry or verify the
   authority of any such party, and Borrower shall hold Bank harmless from any
   damage, claims or liability by reason of Bank's honor of, or failure to
   honor, any such instructions.

14. DESTRUCTION OF BORROWER'S DOCUMENTS.

   Any documents, schedules, invoices or other papers delivered to Bank, may be
   destroyed or otherwise disposed of by Bank six (6) months after they are
   delivered to or received by Bank, unless Borrower requests, in writing, the
   return of the said documents, schedules, invoices or other papers and makes
   arrangements, at Borrower's expense, for their return.

15. CHOICE OF LAW.

   The validity of this Agreement, its construction, interpretation and
   enforcement, and the rights of the parties hereunder and concerning the
   Collateral, shall be determined according to the laws of the State of
   California. The parties agree that all actions or proceedings arising in
   connection with this Agreement shall be tried and litigated only in the state
   and federal courts in the Northern District of California or County of Santa
   Clara.

16. GENERAL PROVISIONS.

        16.1 This Agreement shall be binding and deemed effective when executed
    by the Borrower and accepted and executed by Bank at its Headquarter Office.

        16.2 This Agreement shall bind and inure to the benefit of the
    respective successors and assigns of each of the parties, provided, however,
    that Borrower may not assign this Agreement or any rights hereunder without
    Bank's prior written consent and any prohibited assignment shall be
    absolutely void. No consent to an assignment by Bank shall release Borrower
    or any guarantor from their Obligations to Bank. Bank may assign this
    Agreement and its rights and duties hereunder. Bank reserves the right to
    sell, assign, transfer, negotiate or grant participations in all or any part
    of, or any interest in Bank's rights and benefits hereunder. In connection
    therewith, Bank may disclose all documents and information which Bank now or
    hereafter may have relating to Borrower or Borrower's business.

        16.3 Paragraph headings and paragraph numbers have been set forth herein
    for convenience only; unless the contrary is compelled by the context,
    everything contained in each paragraph applies equally to this entire
    Agreement.

        16.4 Neither this Agreement nor any uncertainty or ambiguity herein
    shall be construed or resolved against Bank or Borrower, whether under any
    rule of construction or otherwise; on the contrary, this Agreement has been
    reviewed by all parties and shall be construed and interpreted according to
    the ordinary meaning of the words used so as to fairly accomplish the
    purposes and intentions of all parties hereto. When permitted by the
    context, the singular includes the plural and vice versa.


                                       14.

<PAGE>   15

                                   REVOLVING
                           LOAN & SECURITY AGREEMENT
                             (Accounts & Inventory)

        16.5 Each provision of this Agreement shall be severable from every
    other provision of this Agreement for the purpose of determining the legal
    enforceability of any specific provision.

        16.6 This Agreement cannot be changed or terminated orally. Except as to
    currently existing Obligations owing by Borrower to Bank, all prior
    agreements, understandings, representations, warranties, and negotiations,
    if any, with respect to the subject matter hereof, are merged into this
    Agreement.

        16.7 The parties intend and agree that their respective rights, duties,
    powers liabilities, obligations and discretions shall be performed, carried
    out, discharged and exercised reasonably and in good faith.

        IN WITNESS WHEREOF, the parties hereto have caused this Revolving Credit
    Loan & Security Agreement (Accounts and Inventory) to be executed as of the
    date first hereinabove written.




ATTEST:                                 BORROWER: DENTAL/MEDICAL DIAGNOSTIC
                                        SYSTEMS, INC.


                                        By: /s/ R. E. WITTMAN
-------------------------------------      -------------------------------------
Title:                                     Signature

Accepted and effective as of
DECEMBER 10, 1997                       Title: VP & CFO
at Bank's Headquarter Office                  ----------------------------------

                                        By:
                                           -------------------------------------
                                           Signature of

             (Bank)
                                        Title:
                                              ----------------------------------


By:  /s/  THOMAS M. HICKS               By:
   -----------------------------------     -------------------------------------
   Signature of THOMAS M. HICKS            Signature of

Title:  VICE PRESIDENT                  Title:
      --------------------------------        ----------------------------------

                                        By:
                                           -------------------------------------
                                           Signature of

                                        Title:
                                              ----------------------------------

                                      15.

<PAGE>   16
[LOGO]

                      AUTOMATIC LOAN PAYMENT AUTHORIZATION


                             Date DECEMBER 10, 1997

Obligor Name (Typed or Printed): DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.

Obligor Number: **  Lender's Cost Center# 95824

Address:  200 N. WESTLAKE BLVD. #202, WESTLAKE VILLAGE, CA 91362
               STREET ADDRESS            CITY          STATE     ZIP CODE

The undersigned hereby authorizes COMERICA BANK-CALIFORNIA ("Bank") to charge
the account designated below for the payments due on the loan(s) as designated
below and all renewals, extensions, modifications and/or substitutions thereof.
This authorization will remain in effect unless the undersigned requests a
modification that is agreed to by the Bank in writing. The undersigned remains
fully responsible for all amounts outstanding to Bank if the designated account
is insufficient for repayment

[X]        Automatic Payment Authorization for all payments on all current and
           future borrowings, as and when such payments come due (which payments
           include, without limitation, principal, interest, fees, costs, and
           expenses).

[ ]        Automatic Payment Authorization for all payments on only the specific
           borrowing identified below, as and when such payments come due (which
           payments include, without limitation, principal, interest, fees,
           costs, and expenses).

           Specific Obligation Number_______________________

[ ]        Automatic Payment Authorization for less than all payments on only
           the specific borrowing identified below, as and when such payments
           come due.

           Specific Obligation Number______________________

           [ ] Principal and Interest Payments only

           [ ] Principal payments only

           [ ] Interest Payments only

           [ ] SPECIAL INSTRUCTIONS/IRREGULAR PAYMENT INSTRUCTIONS

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

   Payment Due Date: Your loan payments of principal and interest will be
   charged to your account as indicated above unless that day is a Saturday,
   Sunday, or holiday in which case such payments will be made on the following
   business day, with interest to accrue during this extension as provided under
   the loan documents.

   Account to be Charged:

   [ ]   Checking  COMERICA BANK-CALIFORNIA      Account No.  **
                                                            --------------
   [ ]   Savings   COMERICA BANK-CALIFORNIA      Account No.
                                                            --------------
(Charges to account are withdrawals pursuant to account resolution)

DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.


By /s/ R. E. WITTMAN                       By
  ----------------------------               -----------------------------------
SIGNATURE OF                               SIGNATURE OF

Its: VP & CFO                              Its:
  ----------------------------               -----------------------------------
TITLE (it applicable)                          TITLE (it applicable)

BY:                                        BY:
  ----------------------------               -----------------------------------
SIGNATURE OF                               SIGNATURE OF

Its:                                       Its:
  ----------------------------               -----------------------------------
TITLE (it applicable)                          TITLE (it applicable)

By:                                        BV:
  ----------------------------               -----------------------------------
SIGNATURE OF                               SIGNATURE OF

Its:                                       Its:
  ----------------------------               -----------------------------------
TITLE (if applicable)                          TITLE (if applicable)


**CONFIDENTIAL INFORMATION OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
  EXCHANGE COMMISSION
<PAGE>   17
                                                             EQUIPMENT
                                                               RIDER
[COMERICA LOGO]

Borrower(s):

                    DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.

     Borrower has entered into a certain Revolving Credit and Security
Agreement (Accounts and Inventory) or a certain Loan and Security Agreement
(Accounts and Inventory) (either hereinafter referred to as "Agreement"), dated
MARCH 7, 1997 with Bank (Secured Party). This EQUIPMENT RIDER (hereinafter
referred to as this Rider) dated DECEMBER 10, 1997 is hereby made a part of and
incorporated into that Agreement.

1.   Borrower grants to Bank a security interest in the following (hereinafter
referred to as "Equipment"):

     (a)  All of Borrower's present machinery, equipment, fixtures, vehicles,
          office equipment, furniture, furnishings, tools, dies, jigs and
          attachments, wherever located, (including but not limited to, the
          items listed and described on the Schedule of Equipment attached
          hereto and marked Exhibit "A" and by this reference made a part hereof
          as though fully set forth hereat);

     (b)  all of Borrower's additional equipment, wherever located, of like or
          unlike nature, to be acquired hereafter, and all replacements,
          substitutes, accessions, additions and improvements to any of the
          foregoing; and

     (c)  all of Borrower's general intangibles, including without limitation,
          computer programs, computer disks, computer tapes, literature,
          reports, catalogs, drawings, blueprints and other proprietary items.

2.   Bank's security interest in the Equipment as set forth above shall secure
each, any and all of Borrower's Obligations to Bank, as the term "Obligations:
is defined in the Agreement; and, the payment of Borrower's indebtedness in the
principal amount of TWO  MILLION FIVE HUNDRED THOUSAND AND NO/100 Dollars
($2,500,000.00) and interest evidenced by VARIOUS NOTES.

3.   Bank may, in its sole discretion, from time to time hereafter, make loans
to Borrower. Loans made by Bank to Borrower pursuant to this Rider shall be
included as part of the Obligations of Borrower to Bank and at Bank's option,
may be evidenced by promissory note(s), in form satisfactory to Bank. Such
loans shall bear interest at the rate and be payable in the manner specified in
said promissory note(s) in the event Bank exercises the aforementioned option,
and in the event Bank does not, such loans shall bear interest at the rate and
be payable in the manner specified in the Agreement.

4.   Borrower represents and warrants to Bank that:

     (a)  it has good and indefeasible title to the Equipment;

     (b)  the Equipment is and will be free and clear of all liens, security
          interests, encumbrances and claims, except as held by Bank,

     (c)  the Equipment shall be kept only at the following locations:

          ---------------------------------------------------------------------

          ---------------------------------------------------------------------

     (d)  the owners or mortgagees of the respective locations are:

          ---------------------------------------------------------------------

          ---------------------------------------------------------------------

     (e)  Bank shall have the right upon demand now and/or at all times
          hereafter, during Borrower's usual business hours to inspect and
          examine the Equipment and Borrower agrees to reimburse Bank for its
          reasonable costs and expenses in so doing.

5.   Borrower shall keep and maintain the Equipment in good operating condition
and repair, make all necessary replacements thereto so that the value and
operating efficiency thereof shall at all times be maintained and preserved.
Borrower shall not permit any items of Equipment to become a fixture to real
estate or accession to other property, and the Equipment is now and shall at
all times remain and be personal property.

6.   Borrower, at its expense, shall keep and maintain: the Equipment insured
against loss or damage by fire, theft, explosion, sprinklers and all other
hazards and risks ordinarily insured against by other owners who use such
properties and interest in properties in similar businesses for the full
insurable value thereof; and business interruption insurance and public
liability and property damage insurance relating to Borrowers ownership and use
of its assets. All such policies of insurance shall be in such form, with such
companies and in such amounts as may be satisfactory to Bank. Borrower shall
deliver to Bank certified copies of such policies of insurance and evidence of
the payment of all premiums thereof. All such policies of insurance (except
those of public liability and property damage) shall contain an endorsement in
a form satisfactory to Bank showing loss payable to Bank and all proceeds
payable thereunder shall be payable to Bank and upon receipt by Bank shall be
applied on the account of Borrower's Obligations. To secure the payment of
Borrower's Obligations, Borrower grants Bank a security interest in and to all
such policies of insurance (except those of public liability and property
damage) and the proceeds thereof and directs all insurers under such policies of
insurance to pay all proceeds thereof directly to Bank. Borrower hereby
irrevocably appoints Bank (and any of Bank's officers, employees or agents
designated by Bank) as Borrower's attorney-in-fact for the purpose of making,
settling and adjusting claims under such policies of insurance and for making
all determinations and decisions with respect to such policies of insurance.
Each such insurer shall agree by endorsement upon the policy or policies of
insurance issued by it to Borrower as required above, or by independent
instruments furnished to Bank that it will give Bank at least ten (10) days
written notice before any such policy or policies of insurance shall be altered
or canceled, and that no act or default of Borrower, or any other person, shall
affect the right of Bank to recover under such policy or policies of insurance
required above or to pay any premium in whole or in part relating thereto. Bank,
without waving or releasing any obligations or defaults by Borrower hereunder,
may at any time or times hereafter, but shall have no obligations to do so,
obtain and maintain such policies of insurance and pay such premiums and take
any other action with respect to such policies which bank deems advisable. All
sums so disbursed by Bank, including reasonable attorney's fees, court costs,
expenses and other charges relating thereto, shall be a part of Borrower's
Obligations and payable on demand.

7.   Until default by borrower under the Agreement or this rider, Borrower may,
subject to the provisions of the Agreement and this Rider and consistent
therewith, remain in possession thereof and use the Equipment referred to
herein in the ordinary course of business at the location or locations
hereinabove designated.

8.   All of the terms, conditions, warranties, covenants, agreements and
representations of the Agreement are incorporated herein and reaffirmed.

9.   Upon a default by Borrower under the Agreement or this Rider, Borrower
upon request of Bank to do so, agrees to assemble and make the Equipment or
any part thereof available to Bank at a place designated by Bank.

10.  Borrower shall upon demand by Bank immediately deliver to Bank and
properly endorse, any and all evidences of ownership, certificates of title or
applications for titles to any of the aforesaid items of Equipment.

11.  Bank shall not in any way or manner be liable or responsible for (a) the
safekeeping of the Equipment; (b) any loss or damage thereto occurring or
arising in any manner or fashion from any clause; (c) any diminution in the
value thereof or (d) any act or default by any person whomsoever. All risk of
Loss, damage or destruction of the Equipment shall be borne by Borrower.

Borrower(s): DENTAL MEDICAL DIAGNOSTIC SYSTEMS, INC.


     /s/ R.E. WITTMAN, VP & CFO
------------------------------------     ------------------------------------
By:                                      By:


------------------------------------     ------------------------------------
By:                                      By:

Accepted this 10TH day of DECEMBER, 1997 at Bank's place of business in SAN
JOSE, CA 95113


                                         By: /s/ THOMAS M. HICKS
                                            ---------------------------------
                                             THOMAS M. HICKS, VICE PRESIDENT
CA 132(12-94)
<PAGE>   18
[COMERICA LOGO]                                                        EQUIPMENT
                                                                         RIDER

BORROWER(S):

     DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.

     Borrower has entered into a certain Revolving Credit and Security
Agreement (Accounts and Inventory) or a certain Loan and Security Agreement
(Accounts and Inventory) (either hereinafter referred to as "Agreement", dated
DECEMBER 10, 1997 with Bank (Secured Party). This EQUIPMENT RIDER (hereinafter
referred to as this Rider) dated DECEMBER 10, 1997 is hereby made a part of and
incorporated into that Agreement.

1.   Borrower grants to Bank a security interest in the following (hereinafter
     referred to as "Equipment"):

     (a)  All of borrower's present machinery, equipment, fixtures, vehicles,
          office equipment, furniture, furnishings, tools, dies, jigs and
          attachments, wherever located, (including but not limited to, the
          items listed and described on the Schedule of Equipment attached
          hereto and marked Exhibit "A" and by this reference made a part hereof
          as though fully set forth hereat);

     (b)  all of borrower's additional equipment, wherever located, of like or
          unlike nature, to be acquired hereafter, and all replacements,
          substitutes, accessions, additions and improvements to any of the
          foregoing; and

     (c)  all of Borrowers general intangibles, including without limitation,
          computer programs, computer disks, computer tapes, literature,
          reports, catalogs, drawings, blueprints and other proprietary items.

2.   Bank's security interest in the Equipment as set forth above shall secure
each, any and all of Borrower's Obligations to Bank, as the term "Obligations"
is defined in the Agreement; and, the payment of Borrower's indebtedness in the
principal amount of TWO MILLION FIVE HUNDRED THOUSAND AND NO/100 Dollars
($2,500,000.00) and interest evidenced by VARIOUS NOTES.

3.   Bank may, in its sole discretion, from time to time hereafter, make loans
to Borrower. Loans made by Bank to Borrower pursuant to this Rider shall be
included as part of the Obligations of Borrower to Bank and at Bank's option,
may be evidenced by promissory note(s), in form satisfactory to Bank. Such
loans shall bear interest at the rate and be payable in the manner specified in
said promissory note(s) in the event Bank exercises the aforementioned option
and in the event Bank does not, such loans shall bear interest at the rate and
be payable in the manner specified in the Agreement.

4.   Borrower represents and warrants to Bank that:

     (a)  it has good and indefeasible title to the Equipment;
     (b)  the Equipment is and will be free and clear of all liens, security
          interests, encumbrances and claims, except as held by Bank,
     (c)  the Equipment shall be kept only at the following locations:

          ----------------------------------------------------------------------
     (d)  the owners or mortgagees of the respective locations are:

          ----------------------------------------------------------------------
     (e)  Bank shall have the right upon demand now and/or at all times
          hereafter, during Borrower's usual business hours to inspect and
          examine the Equipment and Borrower agrees to reimburse Bank for its
          reasonable costs and expenses in so doing.

5.   Borrower shall keep and maintain the Equipment in good operating condition
and repair, make all necessary replacements thereto so that the value and
operating efficiency thereof shall at all times be maintained and preserved.
Borrower shall not permit any items of Equipment to become a fixture to real
estate or accession to other property, and the Equipment is now and shall at all
times remain and be personal property.

6.   Borrower, at its expense, shall keep and maintain: the Equipment insured
against loss or damage by fire, theft, explosion, sprinklers and all other
hazards and risks ordinarily insured against by other owners who use such
properties and interest in properties in similar businesses for the full
insurable value thereof; and business interruption insurance and public
liability and property damage insurance relating to Borrowers ownership and use
of its assets. All such policies of insurance shall be in such form, with such
companies and in such amounts as may be satisfactory to Bank. Borrower shall
deliver to Bank certified copies of such policies of insurance and evidence of
the payment of all premiums thereof. All such policies of insurance (except
those of public liability and property damage) shall contain an endorsement in a
form satisfactory to Bank showing loss payable to Bank and all proceeds payable
thereunder shall e payable to Bank and upon receipt by Bank shall be applied on
the account of Borrower's Obligations. To secure the payment of Borrower's
Obligations, Borrower grants Bank a security interest in and to all such
policies of insurance (except those of public liability and property damage) and
the proceeds thereof and directs all insurers under such policies of insurance
to pay all proceeds thereof directly to Bank. Borrower hereby irrevocably
appoints Bank (and any of Bank's officers, employees or agents designated by
Bank) as Borrower's attorney-in-fact for the purpose of making, settling and
adjusting claims under such policies of insurance and for making all
determinations and decisions with respect to such policies of insurance to pay
all proceeds thereof directly to Bank. Borrower hereby irrevocably appoints Bank
(and any of Bank's officers, employees or agents designated by Bank) as
Borrower's attorney-in-fact for the purpose of making, settling and adjusting
claims under such policies of insurance and for making all determinations and
decisions with respect to such policies of insurance. Each such insurer shall
agree by endorsement upon the policy or policies of insurance issued by it to
Borrower as required above, or by independent instruments furnished to Bank that
it will give Bank at least ten (10) days written notice before any such policy
or policies of insurance shall be altered or canceled, and that no act or
default of borrower, or any other person, shall affect the right of Bank to
recover under such policy or policies of insurance required above or to pay any
premium in whole or in part relating thereto. Bank, without waiving or releasing
any obligations or defaults by Borrower hereunder, may at any time or times
hereafter, but shall have no obligations to do so, obtain and maintain such
policies of insurance and pay such premiums and take any other action with
respect to such policies which Bank deems advisable. All sums so disbursed by
Bank, including reasonable attorney's fees, court costs, expenses and other
charges relating thereto, shall be a part of Borrower's Obligations and payable
on demand.

7.   Until default by Borrower under the Agreement or this Rider, Borrower may,
subject to the provisions of the Agreement and this Rider and consistent
therewith, remain in possession thereof and use the Equipment referred to herein
in the ordinary course of business at the location or locations hereinabove
designated.

8.   All of the terms, conditions, warranties, covenants, agreements and
representations of the Agreement are incorporated herein and reaffirmed.

9.   Upon a default by Borrower under the Agreement or this Rider, Borrower upon
request of Bank to do so, agrees to assemble and make the Equipment or any part
thereof available to Bank at a place designated by Bank.

10.  Borrower shall upon demand by Bank immediately deliver to Bank and properly
endorse, any and all evidences of ownership, certificates of title or
applications for titles to any of the aforesaid items of Equipment.

11.  Bank shall not in any way or manner be liable or responsible for (a) the
safekeeping of the Equipment; (b) any loss or damage thereto occurring or
arising in any manner or fashion from any cause; (c) any diminution in the value
thereof or (d) any act or default by any person whomsoever. All risk of Loss,
damage or destruction of the Equipment shall be borne by Borrower.

Borrower(s): DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.


/s/ R. E. WITTMAN VP & CFO
-------------------------------------   ----------------------------------------
By:                                     By:




-------------------------------------   ----------------------------------------
By:                                     By:


Accepted this 10TH day of DECEMBER, 1997 at Bank's place of business in SAN
JOSE, CA  95113


                                        By: /s/ THOMAS M. HICKS
                                        ----------------------------------------
                                             THOMAS M. HICKS, VICE PRESIDENT

<PAGE>   19
[LOGO]                                                        INVENTORY RIDER
                                                            (REVOLVING ADVANCE)

COMERCIA BANK-CALIFORNIA


Borrower(s):  DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.


     Borrower has entered into a certain Revolving Credit and Security Agreement
(Accounts and Inventory) or a certain Loan and Security Agreement (Accounts and
Inventory) (either hereinafter referred to as "Agreement") dated DECEMBER 10,
1997 with Bank (Secured Party). This INVENTORY RIDER (hereinafter referred to as
this Rider) dated DECEMBER 10, 1997 is hereby made a part of and incorporated
into that agreement.

      1.  At the request of Borrower, made at any time and from time to time
during the term of the Agreement, and so long as no event of default under the
Agreement has occurred and Borrower is in full, faithful and timely compliance
with each and all of the covenants, conditions, warranties and representations
contained in the Agreement, this Rider and/or any other agreement between Bank
and Borrower, Bank agrees to lend Borrower SEVENTY-FIVE AND NO/1000 percent
(75.000% ) of the lower of cost or market value of Borrower's raw materials and
finished goods inventory, and as may be adjusted by Bank, in Bank's discretion,
for age and seasonality or other factors affecting the value of the Inventory,
up to a maximum advance outstanding at any one time of NO/100 Dollars
($__________) upon Borrower's concurrent execution and delivery to Bank of a
Designation of Inventory, or Certification of Borrowing Base, in form
customarily used by Bank. All advances made and to be made pursuant to this
Rider are solely and exclusively to enable Borrower to acquire rights in and
purchase new Inventory, and Borrower represents and warrants that all advances
by Bank pursuant to this Rider will be used solely and exclusively for such
purpose; and since such advances will be used for the foregoing purposes,
Bank's security interest in Borrower's Inventory is and shall be at all times a
purchase money security interest as that term is described in Section 9107 of
the California Uniform Commercial Code.

      2.  Advances made by Bank to Borrower pursuant to this Rider shall be
included as part of the Obligations of Borrower to Bank as the term
"Obligations" is defined in the Agreement; and at Bank's option, advances
pursuant to this Rider may be evidenced by promissory note(s), in form and on
terms satisfactory to Bank. All such advances shall bear interest at the rate
and be payable in the manner specified in said promissory note(s) in the event
Bank exercises the aforementioned option, and in the event Bank does not, such
advances shall bear interest at the rate and be payable in the manner specified
in the Agreement.

      3.  All of the terms, covenants, warranties, conditions, agreements and
representations of the Agreement are incorporated herein as though set forth in
their entirety and are hereby reaffirmed by Borrower and Bank as though fully
set forth hereat.




BORROWER(S):  DENTAL/MEDICAL DIAGNOSTIC SYSTEMS, INC.


/s/ R. E. WITTMAN
-------------------------------------      ------------------------------------
By:                                        By:


-------------------------------------      ------------------------------------
By:                                        By:


Accepted this 10TH day of DECEMBER, 1997 at Bank's place of business in
SAN JOSE, CA 95113.

                                            /s/ THOMAS M. HICKS
                                           ------------------------------------
                                           By:  THOMAS M. HICKS, VICE PRESIDENT