# ABSTRACTS

## INTRA-ARTICULAR PRESSURE MEASUREMENTS IN PATIENTS WITH SUDDENLY DEVELOPING, SEVERELY LIMITED MOUTH OPENING

Dorrit W. Nitzan, Yona Mahler and Ariel Simkin

A condition of sudden, severe, and persistent limited mouth opening, which readily responds to arthrocentesis, is postulated to be the effect of a vacuum between disc and fossa in the upper compartment of the temporomandibular joint. In 16 patients with this condition, the negative intra-articular pressure was found to be significantly lower (mean, -82.6 ± 25.4 mm Hg) than in the control group (mean, -7.7 ± 2.5 mm Hg) (P<.0001). It is suggested that the process underlying the vacuum effect starts with persistent pressure (eg, clenching) resulting in the viscoelastic disc being pressed flat against the fossa. Immediately on cessation of the pressure, the disc resumes its natural biconcave shape, but its rims remain fastened to the fossa. The consequent increased negative pressure in the closed space created firmly anchors the disc to the fossa and any attempt to elicit condyle and disc sliding will only stretch the joint capsule and cause pain. This, in turn, will reflexly prevent the pterygoid muscle from exerting sufficient force to pull the disc and thus release the vacuum. This chain of events may account for the severe and persistent limitation in jaw movement and for the easy reversal of the condition by simple non-surgical treatment.

J Oral Maxillofac Surg 50:1038-1042, 1992

## PREVALENCE OF STRUCTURAL BONY CHANGE IN THE MANDIBULAR CONDYLE

J.M.H. Dibbets and L. Th van der Weele

Estimated on data derived from a longitudinal study of 172 orthodontic subjects, structural

bony change in the mandibular condyle occurs in 5% of the individuals documented from child hood to adulthood. The first appearance generally was between 12 and 16 years of age. Differential diagnosis based upon signs and symptoms of CMD registered simultaneously, as proposed in the 1990 guidelines for craniomandibular disorders appeared to be inconsistent. To illustrate how suddenly the process of bony change may proceed, a case report is presented in which a severe change transpired within a 1-year interval in a 13-year-old patient.

J Craniomandib Disord Facial Oral Pain c:254-259, 1992

## EFFECT OF AN ANESTHETIC INJECTED INTO THE TEMPOROMANDIBULAR JOINT SPACE IN PATIENTS WITH T.M.D.

Wiliam Danzig, Shirley May, Charles McNeill and Art Miller

Twenty-three adult female patients were studied before and after injection of one temporomandibular joint to relieve pain. These patients had exhibited a persistent history of pain within their mandibular, neck, and somatic muscles, despite repeated treatment involving occlusal splints, physical therapy, and biofeedback. Patients were also screened for possible condylar degeneration using corrected tomograms. Initially, patients rated their pain on a linear scale from 0 to 10 and designated the site of the pain on a full-body-profile chart. The presence and location of the pain was determined by manual palpation using a rating scale of 0 to 10, and by the patients designating those regions perceived as painful by marking a full-body-profile chart. After this initial screening, subjects received an injection of 1% lidocaine (1100,000) to the upper intracapsular space of one joint. The pain profile chart was completed by the patients 15 minutes after injection. Twenty of the 23 patients demonstrated a significant decrease in pain located in facial, head, and neck regions. These data suggest that injection of a local anesthetic to the temporomandibular joint will decrease pain for a short time in ipsilateral and contralateral regions of the head and neck.

J Craniomandib Disord Facial Oral Pain 6:288-295, 1992

## DIAGNOSIS AND TREATMENT PLANNING IN ORTHODONTICS

George J. Cisneros

Orthodontic diagnosis and treatment planning topics have become predictable in that reports seem to be reactive to societal dilemmas rather than addressing

fundamental questions of our science. Issues and reports abound on temporomandibular disorders and their relationship to orthodontics. Invest igations of airway function and other topics have tended to compound misunderstandings rather than eliminate them. Furthermore, new technologies heralded as having great promise may eventually fall to the side as mere gimmickry. Well-controlled prospective studies are needed to address many fundamental issues underlying orthodontic treatment. The progress and results from these works will take time to bear fruit.

Current Opinion in Dentistry 1991, 1:595-597

## GROWTH AND DEVELOPMENT IN ORTHODONTICS

Cenrad F. A. Moorrees

Growth and development comprise the infrastructure of clinical diagnosis and treatment planning in orthodontics. The two current key issues have been growth prediction and growth stimulation induced by functional appliances. The stability of results in orthodontics and in the combined orthognathic-orthodontic treatment modality are likewise liked to growth and development. Changes in the untreated dentition after the permanent teeth are present in the mouth provide another important frame of reference for the clinician. The hazards of cephalometric analysis when relying on intracranial reference lines has recently captured a wave of attention, and if comprehended, should revitalize cephalometrics in clinical practice and in research.

Current Opinion in Dentistry 1991, 1:609-621

## THE DISTRIBUTION OF INTERNAL DERANGEMENT IN PATIENTS WITH TEMPOROMANDIBULAR JOINT DYSFUNCTION — PREVALENCE, DIAGNOSIS, AND TREATMENTS

Shoichi Ishigaki, Russell W. Bessette and Takao Maruyama

This study consisted of 355 patients referred to a surgical practice complaining of facial pain, temporomandibular joint (TMJ) sounds, and limited jaw opening. In 247 patients, 360 TMJs were evaluated by arthrography. While 72.2% of them had internal derangement, the remaining 27.8% had normal arthrograms (NID). Among the patients with internal derangement, meniscal displacement with reduction (MDR) was the largest group (47.3%), followed by meniscal displacement without reduction (MD)
(32.3%), meniscal displacement without reduction associated with perforation (MDP) (15.4%), and perforation with normal disk position (P) (5.0%). The NID, MDR, and MD groups showed similar age distributions. The MDP and P groups showed a significantly older mean age. Gender distribution was biased toward females (82.0%). Of the total number of joints, 183 (50.8%) had a history of trauma, 69.9% of which had an internal derangement. In terms of treatment, 100% of the NID group was treated by splint therapy. The MDR group was mostly treated by partial meniscectomy (49.6%) and splint therapy (41.5%). The MD group was mostly treated by total meniscectomy (53.6%) followed by splint therapy (32.1%). The MDP or P groups mostly underwent total meniscectomy (72.5% and 61.5%, respectively).

J Craniomandib Prac, 1992

## TEMPOROMANDIBULAR JOINT DISKECTOMY

Lars Eriksson and Per-Lennart Westesson

The purpose of this study was to evaluate the long-term clinical and radiologic effects of a temporary silicone implant after diskectomy of the temporomandibular joint. Forty-three temporomandibular joints in 43 patients with painful disk displacement underwent a diskectomy. A sheet of medical-grade silicone was temporarily placed in 22 patients; 21 patients did not receive an implant. The patients were clinically and radiologically examined 5 years after surgery. On the basis of symptoms and jaw function, they were classified as having good (30 patients), acceptable (8 patients), and bad (5 patients) results. All the patients with bad results and five of the eight patients with acceptable results had received implants. Erosive changes of the condyle or fossa were seen radiographically at follow-up in eight patients, each of whom had received an implant. No positive clinical or radiologic effects of the implants could be identified. The use of a temporary silicone implant after diskectomy of the temporomandibular joint in patients with internal derangement should be seriously questioned.

Oral Surg Oral Med Oral Pathol
74:259-72, 1992

## COMPLICATIONS OF ORTHODONTIC TREATMENT

Robert L. Vanarsdall

Certain complications and limitations have been associated with orthodontic treatment. The current literature obviously has not addressed all complications, but the following review highlights interesting

findings and studies that may improve understanding and management of root resorption, ankylosis, implants, periodontal damage, instability, and relapse.

Current Opinion in Dentistry 1991, 1:622-633

## ATTRIBUTES OF TINNITUS THAT MAY PREDICT TEMPOROMANDIBULAR JOINT DYSFUNCTION

Jack Vernon, Susan Griest and Linda Press

A collection of 1002 patients with severe tinnitus, drawn from the Tinnitus Data Registry, were retrospectively surveyed to determine which traits or attributes of tinnitus could indicate the possibility of temporomandibular joint dysfunction (TMD) as the cause of tinnitus. The patients were divided into two groups: (1) a TMD group, consisting of 69 patients for whom there was no known cause of tinnitus except for one or more temporomandibular joint (TMJ) indicators and (2) a comparison group with mixed etiologies (n × 860). Seventy three patients were eliminated due to excessive complications relating to cause. The two groups were compared seeking those attributes of tinnitus that significantly separated them. No single benchmark standard was discovered that exclusively indicated tinnitus from TMJ origins. However, a total of 10 "TMJ Indicators" were discovered. The data for each of these indicators is presented and discussed. In addition, the attributes that did not significantly separate the two groups are listed. The study concludes with a recommendation for TMJ referral for those tinnitus patients with unknown etiology who demonstrate any three or more of the TMJ indicators.

## IMPACT OF OVERBITE ON INDICATORS OF TEMPOROMANDIBULAR JOINT DYSFUNCTION

Alan G. Glaros, David L. Brockman and Richard J. Ackerman

Epidemiological studies have suggested that deep overbite is associated with symptoms of temporomandibular dysfunction (TMD). This finding was directly tested by deliberately constituted groups of deep and normal overbite subjects matched for age and sex. Eighty-one subjects participated. Dependent measures included the TMJ Scale test; measures of muscle activity in the right and left frontalis, temporalis, and masseter muscles; and pressure threshold meter readings for the same sites. The results showed no differences between

deep and normal overbite subjects for all the dependent measures studied. The role of overbite alone in producing TMD symptoms is questioned.

Journal of Craniomandibular Practice, 1992

## SURGICAL MANDIBULAR ADVANCEMENT IN

ADOLESCENTS: POST-SURGICAL GROWTH RELATED TO STABILITY

Michael D. Snow, Timothy A. Survey, David Walker and William R. Proffit

Ten of 12 adolescents treated with surgical mandibular advancement showed post-surgical mandibular growth, as indicated by an increase in the distance from condylion to pogonion. In all cases, the growth was expressed vertically relative to the cranial base, so that the chin did not come forward. None of the patients had significant increments of anterior maxillary growth post-surgically. Several patients had vertical maxillary growth, which was compensated by vertical mandibular growth, so that the anteroposterior position of the chin was maintained. Forward growth of the maxilla is minimal after the peak of the adolescent growth spurt, and results of mandibular advancement surgery can be acceptably stable after that time.

Int J Adult Orthod Orthognath Surg 6:143-151, 1991

## ASYMPTOMATIC MANDIBULAR THIRD

MOLARS: ORAL SURGEONS' JUDGEMENT OF THE NEED FOR EXTRACTIONS

Kerstin Knutsson, Berndt Brehmer, Leif Lysell and Madeleine Rohlin

Ten oral surgeons were asked to judge the need for extraction of asymptomatic mandibular third molars. Thirty-six mandibular third molars with equal distribution of angular position, impaction status, and patient's sex and age were selected. To estimate the consistency of judgment, the 36 cases were duplicated so that, in all, 72 cases were judged. The judgment of the oral surgeons was compared with that of 30 general dental practitioners (GDPs). The number of mandibular third molars the oral surgeons proposed to extract varied from 3 to 21 of 36 teeth. The mean number of molars proposed for extraction was 12 for the oral surgeons and 13 for the GDPs. There was no third molar that all the observers in the two groups agreed should
be extracted. About three times as many observers in both groups proposed extraction of molars partially covered by soft tissue. The oral surgeons were unanimous in their judgment not to extract 11 molars, and the GDPs were also unanimous in judgment not to extract two of these. The mean intraobserver agreement within the two groups was comparable, 94% for the oral surgeons and 92% for the GDPs. We conclude that there is a great variation among oral surgeons in their judgment on the need for removal of asymptomatic mandibular third molars. A similar variation in judgment also was observed among GDPs.

J Oral Maxillofac Surg 50:329-333, 1992

## NON-SURGICAL AND INTERACTIVE ORTHODONTICS

G. Frans Currier

Cephalometric radiographic evaluation needs to be supplemented with soft tissue analyses that assist in the proper mechanics. Radiographs remain prescriptive to alter therapy. Patient cooperation is directly related to understanding and applying learning principles that are essential for quality orthodontic care. Prescriptions and new wires continue to make treatment more efficient and exacting. The anomalies of the teeth profoundly affect tooth placement in the occlusion. The transverse plane is the first and most important plane of occlusion that needs early intervention. This plane is directly related to correction of the sagittal through vertical development. The scope of airway and function needs to supplement specific modalities of therapy. Functional appliances usually have significant dento-alveolar effects within the growth process. Individual variation remains the hallmark of human growth and development, with or without therapeutic intervention.

Current Opinion in Dentistry 1991, 1:598-608

## MATERIALS AND APPLIANCES IN ORTHODONTICS: BRAKCETS, ARCH WIRES, AND FRICTION

Robert P. Kusy

The focal point for any orthodontic patient is the form and comfort of his or her appliance. To the practitioner, both can influence the function of the arch wire-bracket combination. The most critical interaction that occurs within the so-called couple is friction. When friction is high, sliding is hampered, as the efficiency and reproducibility of the appliance may be impaired. In this review, the recent advances to control friction and

to modify the arch wire-bracket combination are reviewed.

Current Opinion in Dentistry 1991, 1:634-644

## SURGICAL ORTHODONTICS

David R. Hoffman

This was an interesting year for the surgical orthodontic literature. Excellent large long-term studies addressed the stability of rigid versus wire fixation, lag screws versus bicortical screws, and osteotomy site selection. The effect of orthognathic procedures on speech and hearing deficits, condylar position, and the patient's psyche were reported in detail. Possible solutions to financial difficulties and the concern about blood transfusions were presented. Treatment failures and prediction shortcomings were candidly discussed.

Current Opinion in Dentistry 1991, 1:645-651

## EDUCATION, RESEARCH AND PERSONNEL NEEDS IN ORTHODONTICS

Rolf G. Behrents and Robert G. Keim

Because of changing patterns of dental care delivery, the nature of orthodontic education, research, and personnel needs has changed markedly in recent times. Changes have occurred in the university environment, dental education, and undergraduate and graduate orthodontic education. Orthodontic research is shifting to more clinically oriented topics. Orthodontic personnel needs are being addressed by changing levels of specialist and general practitioner involvement.

Current Opinion in Dentistry 1991, 1:652-656

## MAINTENANCE OF CONDYLE-PROXIMAL SEGMENT POSITION IN ORTHOGNATHIC SURGERY

Kenneth S. Rotskoff, Eugenio G. Herbosa and Peter Villa

Twenty patients underwent bilateral sagittal ramus osteotomy for the correction of mandibular retrognathia. A condylar positioning device (CPD) was used intraoperatively in 10 patients to maintain preoperative condyle-proximal segment position, while the CPD was not used in the other 10 patients. Postoperatively, the condyle-proximal segment positions in both groups were compared and evaluated for vertical, horizontal, and rotational changes. A significant improvement (P<.05) was observed in the vertical and horizontal condylar

position in the group in which the CPD was used. However, there was no significant difference in proximal segment rotation.

J Oral Maxillofac Surg 49:2-7, 1991

## THE EFFECT OF TREATMENT ON FACIAL ATTRACTIVENESS

Ceib Philips, Christopher J. Trentini and Neofitos Douvartzidis

Pre-treatment and post-treatment frontal and profile slides of 13 orthodontic camouflage and 13 orthognathic surgery patients were shown to three panels of judges: an orthodontic, an oral surgery, and a "lay" panel of first-semester dental students. Each judge rated the facial attractiveness of the pre-treatment and post-treatment views of each patient using a visual analog scale. A mean pre-treatment and post-treatment score was then calculated for each treatment group for each judge. Paired t tests were used to compare the treatment groups and time periods. The orthodontic camouflage group was rated as significantly more attractive than the orthognathic surgery patients before treatment. There was no significant change in the facial attractiveness mean score for the orthodontic group, whereas the orthognathic surgery group was rated as showing a significant improvement. However, the orthognathic surgery group was still rated as being significantly less attractive after treatment than the orthodontics-only group.

Int J Adult Orthod Orthognath Surg, 1992; 50:590-594.

## PREVALENCE AND VARIANCE OF TEMPOROMANDIBULAR DYSFUNCTION IN ORTHOGNATHIC SURGERY PATIENTS

C. S. White and M. Franklin

Seventy-five patients were studied retrospectively to assess the prevalence and variance of temporomandibular dysfunction in an orthognathic surgery population. Preoperatively, 49.3% of the sample presented with temporomandibular dysfunction. After orthognathic surgery, of the symptomatic patients, 89.1% had improved temporomandibular function after surgery, 2.7% were unchanged, and 8.1% had increased symptoms. Of the patients asymptomatic prior to surgery, 7.9% developed temporomandibular dysfunction postoperatively. Temporomandibular dysfunction was significantly more prevalent in patients with a Class II skeletal deformity than in those with a Class III deformity, and temporomandibular function generally improved in both groups postsurgically.
# NEWS & NOTICES
AUSTRALIAN SOCIETY
OF ORTHODONTISTS

## PRELIMINARY PROGRAMME
14TH AUSTRALIAN ORTHODONTIC CONGRESS

<figure><img src="image_1.png" /></figure>

## THE VERTICAL DIMENSION

19TH — 23RD
SEPTEMBER, 1993

ADELAIDE
SOUTH AUSTRALIA

## GENERAL INFORMATION

Registration by all participants including invited speakers, delegates and accompanying persons is essential.

<table><caption>### REGISTRATION FEES</caption><thead><tr><th>Full<br>Registration (AUD$)</th><th>Before<br>5/7/1993</th><th>After<br>5/7/1993</th></tr></thead><tbody><tr><td><strong>ASO Members</strong><br>Full & Provisional*</td><td>$425</td><td>$475</td></tr><tr><td><strong>ASO Associate Members</strong></td><td>$570</td><td>$620</td></tr></tbody></table>

<table><tr><td><strong>Affiliated Orthodontic Associations</strong></td><td>$715</td><td>$765</td></tr><tr><td><strong>Accompanying Person</strong></td><td>$260</td><td>$260</td></tr><tr><td><strong>Student</strong></td><td>$120</td><td>$130</td></tr></table>

* PLEASE NOTE: Full and Provisional members of the ASO have the full registration fee of AUD$715 reduced by levies paid. The annual levy is AUD$145. Most members will receive a reduction of AUD$290 for contributions made over two years (AUD$425). For those who have paid only one year's levy, full registration will be AUD $570.

### Registration Fees include:

#### Full Registration

Attendance at all sessions, Stanley Wilkinson Oration and President's Reception, Stonyfell Winery Dinner, lunches, morning teas, changeover dinner and entry to Trade Exhibition.

#### Accompanying Persons

Attendance at the Stanley Wilkinson Oration, President's Reception, Stonyfell Winery Dinner, Changeover Dinner and entry to Trade Exhibition.

#### Student Registration

Attendance at all sessions, Stanley Wilkinson Oration, President's Reception, lunches, morning teas and entry to Trade Exhibition. Registration does not include attendance at social functions. Please enquire at Registration regarding attendance at social functions. Please send a copy of student identification with your registration.

#### Payment of Registration Fees

Payment should be made to the "14th Australian Orthodontic Congress". To ensure confirmation of accommodation, a deposit of one night's accommodation must be received no later than July 31, 1993.

#### International Delegates

All fees are quoted in Australian Dollars (AUD$). Payment should be made by Bank Draft payable on an Australian Bank.

#### Refund of Registration Fees

AUD$45 cancellation fee will be charged to any participant cancelling by the end of July, 1993.

Delegates cancelling registration after 31 July, 1993 but before 31 August, 1993 will be charged a cancellation fee of 25% of the total fee paid. No refund of registration fees will be made if cancellation is received by the Congress Organisers after 31 August, 1992.

#### Confirmation of Booking

Registration will be acknowledged and accommodation bookings confirmed as they are received. Payment must be forwarded before bookings are confirmed. A confirmation letter will be sent to each delegate.

#### Registration Location

The registration desk will be located in the Foyer of the Adelaide Convention Centre

and attended from 1-3 pm on Sunday, 19 September 1993. The Congress Organisers will be in attendance at the Registration desk from 8.30 am - 5 pm on 20, 21 & 23 September.

#### Congress Secretariat

The Office of Continuing Education at The University of Adelaide has been appointed as the Congress Secretariat. Telephone (08) 228 4777. FAX (08) 232 4590.

## SOCIAL/ACCOMPANYING PERSONS' PROGRAMME

### MONDAY
September 20, 1993
Introducing Adelaide

Adelaide — City of Churches and festivals is also known for its unique bluestone mansions, restored heritage buildings and the beautiful parks and gardens which surround the city. This tour — part drive, part walk — will introduce our visitors to the charm and beauty of heritage Adelaide.

Depart: Adelaide Convention Centre.

Time: 9.30 am — 12.30 pm

Cost: $36 per person.

#### Lunch at Jolleys Boathouse

Enjoy a wonderful light lunch at one of Adelaide's most fashionable restaurants.

Time: 12.45 pm.

Cost: $35 per person.

#### Dinner at Stonyfell Winery
(Included in registration fee).

### TUESDAY
September 21, 1993
A Half Day Craft Tour
in the "Enchanted Hills"

Drive through the Enchanted Hills and on the way visit some of our leading South Australian craftspeople at work in their studios. We will have morning tea in a private garden and finish with a leisurely lunch in the historic Mount Lofty House.

Depart: Adelaide Convention Centre.

Time: 9.30 am — 3.30 pm.

Cost: $65 per person, includes lunch, transport, but not drinks.

#### High Tea at The Hyatt

Savour the taste of freshly baked scones with jam and cream served with a selection of teas and coffees while you enjoy the elegant sound of a string quartet.

Time: 3 pm.

Cost: $10 per person.

#### Private Entertainment

A tradition of previous Adelaide Congresses has been an evening of private entertainment. If you are interested in attending one of the dinner parties, please indicate on the registration form. (Limited numbers only).
WEDNESDAY

September 22, 1993

Golf Day — McCracken Golf Club
Victor Harbor

Cost: $50 per person (lunch not included).

Lady Mannum Cruise

Cruise the River Murray and enjoy lunch on board the Lady Mannum.

Depart: Adelaide Convention Centre.

Time: 9.45 am — 4.30 pm.

Cost: $50 per person.

Tour of the Southern Vales

Wineries/Lunch at McClarens on the Lake
Nestled in the heart of the Southern Vales —McClarens on the Lake is a wonderful way to enjoy the award-winning wines of Andrew Garrett and leading Southern Vale winemakers.

Depart: Adelaide Convention Centre.

Time: 9.45 am — 4 pm.

Cost: $50 per person.

Bushwalking — An Afternoon Tour.

Bushwalking — a great Australian pastime. This tour takes you to the Morialta Conservation Park in the Adelaide foothills, where you will be met by an experienced guide. Stroll along the beautiful "Banksia Nature Trail" with its Spring flowering native trees and its abundance of varied birdlife and flowing waterfalls. The Park's lovely old kiosk with roaring log fires is the setting for afternoon tea at the end of your walk. The trail isn't too strenuous, but you will need to wear comfortable walking shoes.

Depart: Adelaide Convention Centre.

Time: 1.30 am — 5.30 pm.

Cost: $50 per person.

THURSDAY

September 23, 1993

Antiques and Artlab

"The healing hands of a surgeon, the detective skills of a Sherlock Holmes and a good supply of saliva" — what could be more descriptive of art conservation? Join us in watching the talented staff of Artlab South Australia as they skilfully restore works of art. After morning tea, we will stroll along to the Antique Centre, which holds a fine collection of antique furniture and jewellery — here we will have a short talk by an expert.

Depart: Adelaide Convention Centre.

Time: 9.30 am — 12.30 pm.

Cost: $20 per person.

Evening — Changeover Dinner
(Included in Registration Fee)

To be held in the magnificent facilities of the Adelaide Convention Centre.

FRIDAY

September 24, 1993

A Day in the Barossa Valley
Post Congress Excursion

This day incorporates the "Best of the Barossa" — wineries, galleries and gardens — all in their setting of rolling hills and

enriched by the tradition of the early German settlers.

Our day will include:

- a trip on the O-Bahn.

- a visit to the delightful hamlet of Bethany.

- a tasting at a number of smaller wineries.

- a winery tour and gourmet lunch at Yalumba.

Depart: Adelaide Convention Centre.

Time: 9 am — 5.30 pm.

Cost: $70 per person.

LUNCHEON DISCUSSION TABLES

Thursday, September 23, 1993

The table leaders and the topics for discussion are:

A. Steve Bajada: Differential diagnosis.

B. Geoff Brown: Space wasting.

C. Paul Buckholz: Computers in Orthodontics.

D. Tony Collett: Structured clinical decision making for Orthodontic/TMD Patients.

E. Ted Crawford: Preadjusted prescriptions — the choice is yours.

F. Simon Freezer: Computerised cephalometrics.

G. Keith Grave: Skeletal age — is it relevant?

H. Paul Hanrahan: A new approach to credit management.

I. Ross Jarvis: Interproximal reduction in the premolar/molar region — the new approach.

J. Stuart McCrostie: Lingual orthodontics.

K. Ken Marshall: Early orthodontic treatment — Phase I intervention.

L. Ron Masson: Adult orthodontics — what are the problems; what are the possible solutions?

M. Grahame Moore: Orthognathic surgery — Is it rigid fixation?

N. Jeff Mount: Prosthodontic options in the management of the congenitally missing tooth.

O. Don O'Donoghue: Cross infection in orthodontic practices.

P. Rick Olive: Prediction of third molar impactions.

Q. Alan Pollard: More bites out of your bits — computers in orthodontic practice.

R. Michael Shearer: Ceramic brackets.

S. Colin Twelftree: TipEdge — back to the future?

T. Michael Woods: Planning for post surgical buccal open bites.

CONGRESS TRADE EXHIBITION

There will be a slight departure from previous arrangements with the Trade Exhibition officially opening on Sunday, September 19 and concluding on the evening of Tuesday 21, rather than continu-

ing on to the final day of the Scientific session. However, there will be ample opportunity for you to participate in the large variety of displays and the special events planned for this compact, but very interesting Exhibition. All Trade Exhibition functions are conveniently located within the Convention Centre complex.

This will be an excellent opportunity to meet the Trade representatives and to see and discuss the latest technological advances in orthodontics. See you there.
Wayne Sampson
Chairman, Trade Exhibition.

TOMY PRE-CONGRESS
HALF DAY COURSE

Saturday, September 18, 1993
at 2 pm

Presenter: Professor Fujio Miura.

Venue: Adelaide Convention Centre.

Topics: 1. Scientific background of the direct bonding method.

2. Clinical application of Super Elastic NiTi alloy wire.

Cost: $95.

For many years Professor Miura has been the world's leading researching in direct bonding and NiTi alloy wires. Early registration is recommended as course numbers will be strictly limited. Please note that this course is open only to Congress delegates.

THREE DAY PRE-
CONGRESS TIP-EDGE
COURSE

An added feature to this year's Scientific Programme will be a limited participation course on the Pre-adjusted TipEdge appliance presented by Dr. Tom Rocke and Dr. Richard Parkhouse. The course is planned for Thursday, Friday and Saturday, September 16, 17 and 18. It is very much a "hand-on" course with the use of three prebanded flexible typodonts as well as extensive illustration and discussion of treatment. With many years of TP courses behind them we are assured of a highly professional and interesting programme on this fast developing technique from our International presenters. The Committee wishes to emphasize that early enrolment will avoid disappointment as the course is limited to sixty-five delegates.

Course Contents: TipEdge Guide Manual (2nd Edition revised); Use of three prebanded flexible typodonts; All materials needed to work with typodonts; Straight Shooter Ligature Gun; Detailed instruction of diagnosis and treatment mechanics; Viewing of instructional videos; Two kits of TipEdge brackets for use on patients in your practice; Lunches
and coffee breaks; Certificate of course completion.

Course Fee: AUD$850.

Venue: Adelaide Convention Centre.

Please note that this course is open only to Congress delegates.

## THE FOURTEENTH STANLEY WILKINSON ORATION

The inaugural Stanley Wilkinson Oration was given by Dr. P.R. Begg in 1961 to honour this pioneer of our profession. Stanley Wilkinson trained with Edward Angle and returned to Australia where he organised the formation of the Australian Society of Orthodontists. Together with his wife, he was responsible for the establishment of the Australian Society of Orthodontists' Foundation for Research and Education.

William Faulding Scammell, C.B.E. has a long and distinguished career in manufacturing, pharmaceuticals and business. He retired as chairman of F.H. Faulding and Co. Ltd. in November 1989 and remains a director of the Company, having presided over a period of exceptionally strong growth, firmly grounded in basic research. Fauldings enjoys an enviable reputation for excellence throughout the world and the company is frequently cited for awards and is a fine example of Australian initiative and development.

William Scammell will be the most recent in a succession of highly distinguished orators, being without doubt most worthy to join their ranks.

### PAST ORATORS

1961: Dr. P.R. Begg

1964: Sir Kenneth Adamson

1966: Dr. A. Thornton Taylor

1969: Dr. R.S.D. Gargett

1972: Prof. G.J.V. Nossall

1974: Sir. Herman Black

1977: Prof. G.N. Davies

1980: Prof. K. Sutherland

1982: Prof. Geoffrey Howe

1984: The Hon. Mr Justice Michael Kirby

1986: Dr. R.J. Norton O.B.E.

1989: Prof. Donald Watts

1991: Prof. Charles Oxnard

### Prof. BENGT INGERVALL
University of Berne, Switzerland

1. The aetiology and treatment of dento-alveolar open bite.

2. The treatment of skeletal open bite.

3. The treatment of Angle Class II div. 2 malocclusion.

The presentation will cover the effects of sucking habits as well as the influence of the function and position of the tongue in the aetiology of the malocclusion. The results of recent studies of the effect of pressure from the lips and tongue on the teeth will be compared and contrasted with the data from earlier investigations. Principles of treatment together with the results of surgical tongue reduction, and effects of tonsilectomy and adenoidectomy will be discussed.

In the treatment of skeletal open bites, the needs and possibilities of treatment by camouflage, growth modification or orthognathic surgery will be discussed on the basis of clinical cases and research. Under the heading 'growth modification' the effects of muscle training, activator therapy and different types of bite-blocks will be covered. The skeletal characteristics and hypotheses regarding aetiology will be discussed.

The characteristics of a Class II div. 2, the role of pressure from the upper lip and the need for treatment viewed from the point of function of the masticatory system as well as the question of a posterior displacement of the mandible will be discussed. Treatment involving camouflage, growth modification and orthognathic surgery will be demonstrated and evaluated in a series of treated cases.

### Prof. PETER SINCLAIR
University of Southern California, U.S.A.

1. Orthognathic diagnosis and treatment planning for the vertical dimension.

2. Orthognathic treatment techniques for short and long face problems.

3. Complications and stability of orthognathic treatment for the vertical dimension.

This presentation will address surgical-orthodontic diagnosis and treatment planning for the vertical dimension. Both case examples and recent clinical research information will be used to provide objective criteria as to when orthognathic surgical treatment is indicated. Using both cephalometric and clinical information, detailed diagnostic and treatment planning evaluations will be carried out for the skeletal, dental, and facial aspects of vertical problems.

The principles of orthodontic mechanics which deal with problems such as vertical

maxillary excess and vertical maxillary deficiency will be described using case examples. The techniques for orthodontic levelling including the use of segmental mechanics to deal with steps, cants, and rotations of the occlusal plane as well as differences in treatment techniques for rigid and wire fixation cases will be discussed. Details of post-operative finishing and post-surgical retention will also be reviewed.

Some of the more commonly seen complications will be discussed from the perspective of their early recognition, prevention, and management. Problems in pre-surgical orthodontic preparation as well as surgical technique and their consequences will be reviewed. The latest information on vertical stability in orthognathic surgical cases will be reviewed focusing on the differences between rigid and wire fixation as well as the differences between one- and two-jaw surgeries.

### Prof. DONALD WOODSIDE
University of Toronto, Canada

1. Diagnosis and treatment of malocclusions characterised by excess lower anterior facial height.

2. Clinical impressions of overclosure in class II and class III treatment.

3. The Speed appliance.

The first presentation deals primarily with the diagnosis and treatment of anterior open bite using the posterior occlusal bite block, spring load bite blocks, active vertical correctors and elastic open activators, in association with conventional fixed appliances. Recent research of the effect of nose and pharyngeal airway obstruction on face height and mandibular growth direction will be discussed.

The second lecture is of a clinical nature dealing with the problems of patients presenting with varying degrees of overclosure with different types of malocclusion.

The Speed appliance is a new advance in orthodontic bracket and treatment design. It is used by 20% of North American orthodontists and is also used in Great Britain, Germany, Sweden, Italy and Switzerland. The bracket combines a high degree of miniaturization with the augmentation of tooth movement by a spring mechanism contained within the bracket. Principles underlying treatment with this appliance will be outlined.

### Dr. VICTOR WEST

The vertical dimension spectrum.

Like religion, the vertical dimension appears to mean different things to different people at least in relation to the manner in which the phenomenon is communicated.
The obligation to teach to both undergraduate and post-graduates the concepts of the establishment, the maintenance and the alteration of the vertical dimension, heightens one's awareness, firstly to the lack of uniformity of terminology, and secondly to the significant variation in the methodology used to determine its magnitude however expressed. The introduction into the dental literature by Ricketts in 1964 of the terminology Brachyfacial, Mesofacial and Dolichofacial offered the possibility of at least a qualitative classification of craniofacial morphology in a vertical direction. As a result of subsequent research in this area I believe there is now a body of data which provides a quantitative basis to support this classification. It is a principle of science that the ability to measure and record any phenomenon facilitates the problem of its communication to others.

It is my hope that an acceptance of the validity of a number of craniofacial parameters expressed as angles and ratios rather than absolute linear measurements will lead to a more uniform result in the classification and communication of craniofacial morphology in the vertical dimension.

## Dr. DARRYLE BOWDEN

The development of the vertical dimension — its significance to treatment planning.

The individual facial patterns are established by as early as 4-6 months in utero. These patterns tend to be consistent in trend during their development. Whilst local factors frequently modify these patterns it is usually within definite areas, each individual varying in response and mofidication. These individual responses are frequently obscured to be represented as prima facie aetiological agents responsible for the apparent total pattern change. Undoubtedly orthodontic and/or orthognathic treatment procedures produce significant changes in the appearance of these patterns by masking within the dentofacial area; but many of these dentofacial changes produced during treatment, tend to "revert to pattern" when examined 10-20 years after treatment, while others show remarkable stability.

## Dr. GEOFFREY HEITHERSAY

Vertical endodontic dimensions of significance to orthodontists.

There are many interactions between orthodontics and endodontics and some of these involve the vertical dimension. Severe dental injuries, such as crown root or low transverse root fractures usually require combined therapy to achieve a successful and functional result. Orthodontic root extrusion in the vertical dimension allows

restoration of these otherwise unsalvagable fractured teeth. A long term evaluation of teeth treated by combined therapy involving rapid root extrusion will be presented.

Ankylosis which may follow some luxation injuries or following tooth reimplantation poses a major clinical problem in the developing dentition, having serious implications to the vertical dimension. Methods of dealing with a tooth held in occlusion will be discussed.

Finally invasive cervical resorption, a process which largely occurs in the vertical dimension, should be of great concern to orthodontists as a positive relationship between this condition and orthodontic treatment of invasive cervical resorption will be presented along with orthodontic implications.

## Prof. ALASTAIR GOSS
University of Adelaide, S.A.

Surgical Correction of Vertical Dimension.

The facial skeleton may exhibit gross deformity in the vertical dimension. There may be vertical excess or deficiency involving the maxilla, mandible or chin. These may occur in isolation, or in combination or be asymmetric.

Current Oral and Maxillofacial Surgical techniques allow for precise correction of all of the various skeletal deformities. This will be demonstrated by surgical cases treated by the Oral and Maxillofacial Unit, The University of Adelaide.

## Dr. MILTON SIMS

Molar vertical changes with Begg treatment.

The effects of Begg treatment on the vertical component of the dentofacial complex are not well documented or understood. When the function of the anchorage bends is correctly integrated with the stimulating action of the elastic modules, the palatal and occlusal planes are stabilised and controlled in the vertical dimension. Under these circumstances, incisor retroclination can be obviated, there is efficient bite opening, and the need for incisor torque is minimised.

Concomitant changes may also occur in the mandibular molar relationships in non-extraction and extraction cases. In controlled treatment with unforced molar elevation there is a balanced vertical response at the posterior regions of the mandible so that molar elevation and mandibular rotation are not directly related. Consequently, the reported characteristic of marked mandibular plane opening and subsequent closure (Ball and Hunt, 1991; Williams, 1970) is not a significant aspect of

treatment. Features of vertical change with Begg treatment will be documented and compared with those reported to occur with functional appliances (Woodside, 1987).

## Prof. TERRY FREER
University of Queensland, Qld.

Open bite — are we missing something?

The treatment of open bite is a matter of concern to orthodontists. Problems arise in diagnosis, mechano-therapy and post-treatment techniques have greatly improved the predictability of treatment objectives. Nevertheless, the aetiology of open bite is difficult to determine accurately in most cases. The vast literature on this topic has dealt predominantly with the skeletal aspects. The diagnostic value of skeletal measurements is questionable at best.

Little attention has been directed to the muscular component of open bite aetiology. Measurements of muscle performance are difficult to devise. Circumstantial evidence would suggest that we should be giving much greater attention to the muscle component of the cranio-facial system in our research, diagnosis and treatment of open bite.

## Dr. TOM WILKINSON

The influence of vertical dimension on craniomandibular disorders.

Orthodontists have conceptualised ideals for the vertical dimension of the face and the coupling of anterior teeth. A large percentage of the population demonstrate wide variations from these ideals and we are faced with difficult decisions as to whether we would intervene to promote long term harmony. Treatment to correct these variations may be initiated for reasons of dental or facial aesthetics or to "improve" function. This presentation will discuss the dilemma of whether treatment should be initiated to prevent or reduce craniomandibular disorders where there are variations from ideal vertical dimension. In particular, the role of deep and open bites will be considered in the development of these disorders. The incidence of craniomandibular disorders in post orthodontic patients will be reviewed.

## Prof. TASMAN BROWN
University of Adelaide, S.A.

Dr. AMANDA ABBOTT
Dr. MICHAEL NUGENT
Mr. DAVID DAVID

This presentation will present an introduction by Professor Brown, who will talk about the Cranio-Facial Unit and the work of its Scientific Unit in relation to the development
of systems to meet the need for objective
measurements of craniofacial deformities,
trauma, cleft lip and palate and the rarer
craniofacial deformities. Locally developed
cephalometric programmes used at the
Unit will be outlined, particularly those
designed for the two and three dimensional
measurements of facial profiles and asym-
metries, and the transition from these
programmes to advanced three dimen-
sional imaging and measurement of CT
scan data will be described.

Dr. Abbott will describe the interactive
interrogation of CT data for the determina-
tion of craniofacial osseous landmarks in
three dimensions, contour profiles for solid
modelling, measurements of distances and
angles and determination of volumes of
regions of interest. Examples will be shown
of the use of 3D point configurations of
landmarks to describe the morphology of
the craniosynostoses, clefts and trauma. In
addition, the development of 3D standards
based skeletal material will be described.

Dr. Michael Nugent will talk about
orthodontic management. Vertical problems
are particularly difficult to handle in ortho-
dontics and there is a direct relationship
between functional occlusion and cos-
metics that has to be carefully monitored to
produce the optimal result. With the most
severe cases of vertical discrepancy one
often achieves the most pleasing results.
The interaction of surgery and orthodontics
is absolutely essential to produce a good
cosmetic and functional occlusion in vertical
growth abnormalities.

Mr. David will emphasise the use that is
made of the scientific and orthodontic
analyses in planning surgery. Some results
of surgery in dento-facial deformity-
symmetrical and asymmetrical; and cranio-
facial deformity involving the upper, middle
and lower thirds of the face will be
presented. Examples will be given of the
clinical applications of the information
obtained from the scientific group, the
value of planning with the orthodontist and
the implementation of the surgical plan.