**Exhibit10.17**

**AMENDMENT LETTER**

From:     Sirona DentalSystems, Inc, as Obligors’ Agent under the Senior Facilities Agreement (asdefined below) for and on behalf of each of the Obligors

To:          J.P. MorganEurope Limited (as Facility Agent under the Senior Facilities Agreement (asdefined below))

5 December 2006

DearSir,

**1.**                                      Introduction

(a)                                  We refer to thesenior facilities agreement dated 22 November 2006 and made between, amongstothers, Sirona Dental Systems, Inc., Schick Technologies, Inc., Sirona DentalSystems GmbH, Sirona Dental Services GmbH, Sirona Dental Systems LLC, SironaHolding  GmbH, Sirona Immobilien GmbHtogether with J.P. Morgan plc and UBS Limited as mandated lead arrangers, J.P.Morgan Chase Bank, N.A. and UBS Limited as original lenders and J.P. MorganEurope Limited as facility agent (the **Senior FacilitiesAgreement**);

(b)                                 Capitalised termsdefined in the Senior Facilities Agreement have the same meaning when used inthis letter, unless expressly defined in this letter.

**2.**                                      Amendments

Pursuant to Clause 38 of the Senior Facilities Agreement, we request theMajority Lenders’ approval that the following provisions of the SeniorFacilities Agreement are amended as follows:

(a)                                  the crossreference to paragraph 2(d) of Part 1 of Schedule 2 (*Conditions Precedent to Delivery of a Utilisation Request*)in the definition of “Funds Flow Statement” in Clause 1.1 (*Definitions*) be amended to refer toparagraph 2 (c) of Part 1 of Schedule 2;

(b)                                 the crossreference to paragraph (g) of Clause 21.9 (*Limitationon Payment Obligations by German Guarantors and limitation regarding LTIBRs*)in the defintion of “German Borrower” in Clause 1.1 (*Definitions*) be amended to refer to paragraph  (h) of Clause 21.9;

(c)                                  the crossreference to sub-paragraph (b)(viii) of Clause 25.14 (L*oans and credit*) in the defintion of“Invested Funds” in Clause 1.1 (*Definitions*)be amended to refer to paragraph (b)(vii) of Clause 25.14;

(d)                                 the crossreference to paragraph 8 of Part II of Schedule 2 (*Conditions Precedent*) in the definition of “Legal Opinions”in Clause 1.1 (*Definitions*) beamended to refer to Paragraph 9 of Part II of Schedule 2;

(e)                                  the crossreference to paragraph (c) of Schedule 12 (*CertainFunds Default*)  in Clause 4.3(*Certain Funds*) be amended torefer to Paragraph (b) of Schedule 12;

(f)                                    paragraph (d) ofClause 11.11 (*Restrictions*) beamended by the insertion of the words “(other than under Clause 11.8 (*Equity Proceeds*) or Clause 11.9 (*Disposal Proceeds*))” after the words “ anypart of the Revolving Facility which is prepaid “ in such clause;

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(g)                                 the crossreference to paragraph (c) of Clause 11.7 (*Exit*)in paragraphs (a) and (d) of Clause 11.12 (*Prepayment elections*)be amended to refer paragraph (b) of Clause 11.7;

(h)                                 Clause 16.3 (*Tax Indemnity*) be amended by the deletionof the word “and” and its replacement with the word “or” at the end of theparagraph (b) (i) of such clause;

(i)                                     the crossreference to sub-paragraph (b) (iii) of Clause 25.7 (*Acquisitions*) in the defintion of “Consolidated AdjustedEBITDA” in Clause 24.1 (*Financialdefinitions*) be amended to refer to sub-paragraph (b) (ii) of Clause25.7;

(j)                                     the crossreference to paragraph (a) of Clause 23.1 (*FinancialStatements*)  in the defintionof “Semi-Annual Financial Statements” in Clause 24.1 (*Financial definitions*) be amended to referto paragraph (b) of Clause 23.1;

(k)                                  paragraph (a) ofClause 24.2 (*Financial condition*)be amended by the deletion of the word “less” and its replacement with the word“greater” in the third line of such clause;

(l)                                     the cross referenceto sub-paragraph (b) (iii) of Clause 25.7 (*Acquisitions*)in Clause 24.4 (*Adjustments*) beamended to refer to sub-paragraph (b) (ii) of Clause 25.7;

(m)                               the crossreference to sub-paragraph (xvi) in sub-paragraph (xvi) of Clause 25.11 (*Negative pledge*) be amended to refer tosub-paragraph (xv) of such clause;

(n)                                 the crossreference to sub-paragraph (b) (vii) of Clause 25.14 (*Loans and Credit*) in paragraph (c) ofClause 25.16  (*Dividends, share capital redemptions and payments on subordinated debt*)be amended to refer to sub-paragraph (b) (vi) of Clause 25.14.

**3.**                                      Agreement

Bycountersigning this letter the Facility Agent (acting on the instructions ofthe Majority Lenders) agrees to the amendments set out above.  Except as expressly amended by this letterthe Finance Documents shall continue in full force and effect in accordancewith their respective terms.

**4.**                                      Governing Law

Thisletter is governed by English law.

Thisletter is a Finance Document.

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Please sign and return a copyof this letter to confirm your agreement to the above.

Yoursfaithfully,

 
| **/s/ SIMONE BLANK**                                         | ** ** |
|--------------------------------------------------------------|------------|
| ** **                                                   |
| for                                                          |
| Sirona Dental  Systems, Inc                                  |
| for itself and  as agent for each                            |
|                                                         |
| of the other  Obligors under the Senior Facilities Agreement |

 

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We agree to the above.

 
| **/s/ CYRUS METHA**                    | ** ** |
|----------------------------------------|------------|
|                                   |
|                                   |
| for                                    |
| **J.P.  MORGAN EUROPE LIMITED**        |
| as Facility  Agent for                 |
|                                   |
| and on behalf of  the Majority Lenders |
| under the Senior  Facilities Agreement |

 

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