# ABSTRACTS

## TMJ PERFORMANCE AND BEHAVIOUR IN PATIENTS MORE THAN 6 YEARS AFTER LE FORT I OSTEOTOMY

de Mol van Otterloo JJ, Dorenbos J, Tuinzing DB, van der Kwast WAM

Sixteen non-cleft patients treated by one piece Le Fort I osteotomy were investigated for TMJ symptoms. Clinical examination and subjective assessment by the patients were used over a 6-year period. No increase in symptoms was recorded in the osteotomy group as compared to the general population, however, condylar atrophy was seen in two patients. Both of these patients were classified as a high mandibular plane angle, with absolute mandibular retrognathism. This suggests that this group may be at greater risk of condylar atrophy.

British Journal of Oral and Maxillofacial Surgery 1993; 31: 83-86.

## COMPARATIVE CEPHALOMETRIC ANALYSIS IN PATIENTS WITH X-ChROMOSOME ANEUPLOIDY

Babic M, Scepan I, Micic M

The influence of abnormal sex-chromosomes constitution on cranial growth, shape and position of the craniofacial structures was analysed. Reduced cranial growth was found in

women with Turner's syndrome (45 XO chromosome constitution) and in men with Klinefelter's syndrome (47 XXY chromosome constitution). Lack of, or an extra, X chromosome produced opposite effects on cranial-base flexion, jaw displacement and maxillary and mandibular inclination to the anterior cranial base. An extra X chromosome affected deviation in sagittal jaw relation while lack of an X chromosome influenced mandibular shape.

Archives of Oral Biology 1993; 38: 179-183.

## FACIAL PALSY AFTER SAGITTAL SPLIT OSTEOTOMIES

de Vries K, Devriese PP, Hovinga J, van den Akker HP

Facial nerve palsy following a sagittal split osteotomy is a rare but serious complication. The incidence of facial nerve injury in a group of 1747 patients who had undergone a bilateral sagittal split osteotomy (3494 sagittal splits) was determined and proved to be 0.26% (9 cases). The case histories of 2 patients are presented, and the etiology, diagnosis, treatment and prevention of this complication are discussed.

Journal of Cranio-Maxillo-Facial Surgery 1993; 21: 50-53.

## LONG-TERM OSSEOUS AND SOFT TISSUE CHANGES AFTER LARGE CHIN ADVANCEMENTS

Polido WD, Bell WH

When a large chin advancement is performed and broad musculo-periosteal pedicle is preserved, excessive stretching of the suprahyoid musculature may occur, leading to instability or resorption of the advanced genial segment. The present study was designed to evaluate long-term osseous and soft tissue changes after large advancement genioplasties (greater than 10mm), achieved by horizontal osteotomy of the inferior border of the mandible, with preservation of a musculo-periosteal pedicle to the advanced genial segment.

Bone remodelling and the inherent soft tissue changes were radiographically assessed in a long-term follow-up period (mean = 26.8 months), with attention to observe progressive osseous changes. Despite the observed 17% bone resorption, the enveloping soft tissues of the chin followed the bony movement in a ratio of 1:0.83. Osseous resorption was not progressive, and the soft tissue changes remained unaltered. A broad musculo-periosteal pedicle consistent with the surgical objective should remain attached to the advanced genial segment to minimize osseous resorption and achieve more predictable soft tissue changes. We emphasize the need for a longer follow-up period (25-30 years) to determine the effect of the stabilization devices and osseous remodelling, especially in younger patients.

Journal of Cranio-Maxillo-Facial Surgery 1993; 21: 54-59.

## CLINICAL OBSERVATIONS OF CLEFT LIP AND PALATE

Precious DS, Delaire J

In surgical management of cleft lip and palate, appreciation of the special anatomy and physiology of the human premaxilla is more important than the question of whether it is a separate bone. To take advantage of the potential of the premaxilla, both primary and secondary surgical procedures must strive to establish a nearly normal medial septal system and nasolabial musculature. To complement accurate muscle surgery of the lip and soft palate, the characteristics and functions of the mucoperiosteum that covers the palate must be respected. The quality of subsequent facial growth can be monitored with the architectural craniofacial cephalometric analysis. By adopting a physiologic approach to cephalometrics, the clinician can avoid some common errors of interpretation.

Oral Surg Oral Med Oral Pathol 1993; 75: 141-151.
## DESCRIPTIVE TERMINOLOGY FOR JAW ANOMALIES
### Obwegester HL

A descriptive terminology for jaw abnormalities was developed and has been used for many years. This terminology was based primarily on inspection of patients and evaluation of cephalometric x-ray images and defines the anatomic location of abnormalities. It aids in communication between doctors of different specialities.

Oral Surg Oral Med Oral Pathol 1993; 75: 138-140.

## LOCAL RESIDUAL RIDGE AUGMENTATION WITH SOLID HYDROXYAPATITE BLOCKS: PART II - CORRECTION OF LOCAL RESORPTION DEFECTS IN 50 PATIENTS
de Wijs FLJA, de Putter C, de Lange GL, de Groot K

Replacement of anterior teeth with fixed or removable prostheses is often a compromise, because the resorbed residual ridge in the area of the missing teeth cannot be ideally restored functionally and aesthetically at the same time. To address this problem, 67 blocks of hydroxyapatite were placed subperiosteally to improve residual ridge resorption defects subsequent to loss of anterior teeth in 50 patients. The implants were evaluated clinically and radiographically for 6 months to 7 years after implantation. Results indicate that the suggested approach improves the aesthetic results and the prognosis of fixed prostheses.

J Prosthet Dent 1993; 69: 514-9.

## EFFECT OF AGE AND SEX ON CRANIOMANDIBULAR DISORDERS
### Koidis PT, Zarifi A, Grigoriadon E, Garefis P

The purpose of this study was to investigate the effect of age and sex on

craniomandibular disorders. A total of 195 subjects were examined, 148 women and 47 men. The range of age was 16 to 70 years. Clinical and anamnestic examination data established the ratio of women to men as 4:1. The prevalence of clicking, headache, teeth-clenching, hypomobility, difficulty in mastication, and neuromuscular symptoms was greater among young women than in other age and sex groups. There was a statistically significant correlation between severity of symptoms and age among women, and a relative decline by age in the prevalence of symptoms for both sexes. Finally, younger patients showed a greater prevalence of neuromuscular symptoms, whereas older patients had more peripheral symptoms.

J Prosthet Dent 1993; 69: 93-101.

## STATISTICAL ANALYSES ON THE SUCCESS POTENTIAL OF OSSEOINTEGRATED IMPLANTS: A RETROSPECTIVE SINGLE-DIMENSION STATISTICAL ANALYSIS
Lill W, Thornton B, Reichsthaler J, Schneider B

Osseointegrated implants are a form of therapy that is finding increasing application in dental treatment. Long-term success can be ensured if the results of recall examinations are systematically documented. Life table analyses are being used to a growing extent to ensure objective assessment of the success of osseointegrated implants. With the help of the statistical method designed by Kaplan-Meier and Cutler-Ederer in 1958, the survival time of the implant can be calculated and the relationship between various co-variables and the service time of the implants can be determined. This study calculates the success potential of 683 osseointegrated implants (IMZ and Branemark) using the customary input-output statistics and life table analyses to explain the discrepancy between the two statistical methods, based on the results obtained.

J Prosthet Dent 1993; 69: 176-85.

## DENTAL FACTORS ASSOCIATED WITH TEMPOROMANDIBULAR JOINT SOUNDS
### Wabeke KB, Spruijt RJ

Dental factors commonly associated with signs and symptoms of temporomandibular disorders were investigated in a group of non-patients. A highly sensitive technique was used to establish the presence of temporomandibular joint (TMJ) sounds. In a discriminant analysis non-working side interferences, attrition, molar contacts, horizontal range of jaw movement, and morphologic occlusion contributed significantly to the prediction of sounds. Further study of morphologic aspects of the joint and stress-related parafunctions may contribute to the understanding of the development of TMJ sounds. We concluded that TMJ sounds are a fairly common sign associated with mild deviations in certain morphologic and functional aspects of the stomatognathic system.

J Prosthet Dent 1993; 69: 401-5.

## SKELETAL STABILITY FOLLOWING MINIPLATE FIXATION AFTER BILATERAL SAGITTAL SPLIT OSTEOTOMY FOR MANDIBULAR ADVANCEMENT
### Abeloos J, de Clercq C, Neyt L

Skeletal stability after monocortical miniplate fixation of bilateral sagittal split osteotomies to advance the mandible was evaluated in 20 patients. Three angles and four linear measurements were analyzed on lateral cephalometric radiographs before surgery, immediately after surgery, and at least 6 months after surgery. The mean horizontal advancement at pogonion was 5.0mm; 6 months after surgery the advancement increased 0.3mm because of occlusal settling. The mean lengthening of the distance gonion to menton was 5.8mm and a relapse of 0.3mm (5.2%) was found. The mean increase of anterior facial height measured at long-term follow-up was 3.6mm. This study shows
that fixation of the advanced mandible with intraorally applied monocortical miniplates after the bilateral sagittal split osteotomy is a stable procedure.

J Oral Maxillofacial Surg 1993; 51: 366-369.

## OPHTHALMIC COMPLICATIONS ASSOCIATED WITH ORTHOGNATHIC SURGERY

Lanigan DT, Romanchuk K, Olson CK

Ophthalmic complications are rare following maxillary osteotomies. Potential complications include a decrease in visual acuity, extraocular muscle dysfunction, neuroparalytic keratitis, and nasolacrimal problems involving both an increase or a decrease in tearing. Ophthalmic injuries appear to be primarily mediated through indirect injuries to neurovascular structures occurring from tractions, compression, or contrecoup injuries from forces transmitted during the pterygomaxillary dysfunction using an osteotome or from fractures extending to the base of the skull or orbit associated with the pterygomaxillary dysfunction or the maxillary down-fracture. A review of the literature of previous ophthalmic complications as well as eight new cases are reported. The possible etiologic basis for these injuries is discussed in detail as well as treatment possibilities when appropriate.

J Oral Maxillofacial Surg 1993; 51: 480-494.

## LOADING ON THE TEMPOROMANDIBULAR JOINTS WITH FIVE OCCLUSAL CONDITIONS

Ito T, Gibbs CH, Marguelles-Bonnet R, Lupkiewica SM, Young HM, Lundeen HC, Mahan PF

Loading may be an important factor in temporomandibular joint stability and function. The purpose of this study was to estimate loading on the TMJs by comparing condylar movements during

clenching on different types of occlusal splints.

Five adult subjects, were were 24 to 27 years of age and had complete dentitions in good arch alignment and a clearly defined intercuspal position, were selected. Five types of splints were made for each subject.

* Stabilization splint with uniform occlusal contact of the anterior and posterior teeth and made near centric occlusion.

* Anterior splint providing anterior tooth contract only on a flat surface perpendicular to the long axis of the mandibular incisor teeth with the mandible near the intercuspal position.

* Anterior repositioning splint holding the condyles 0.5 mm to 1 mm anterior and inferior to the intercuspal position and with uniform occlusal contact of all teeth.

* Bilateral pivot splints with pivots placed bilaterally between the second molars but with no other occlusal contacts and the mandible at centric occlusion.

* Unilateral pivot splint with a pivot placed between the second molars on one side of the dental arch and the mandible at centric occlusion.

Each subject was asked to close comfortably onto the adjusted splint and then to open-close-clench on the splint at least five times. Jaw motion was recorded by six incremental, photo-optical transducers mounted between maxillary and mandibular facebows. The lightweight facebows were connected to the jaws by cast metal clutches which were bonded to the facial surfaces of the teeth with a glass ionomer cement. The very small condylar movements from "close comfortably" to "clench" were measured. Condylar movements also were recorded during manual elevation of the mandible on the non-pivot side when the patients were wearing unilateral pivot splints.

Splints designed without posterior tooth support resulted in superior condylar movement during clenching. Biting on a splint with anterior contact effectively guided the condyles to a superior position. Biting on bilateral posterior pivots did not distract the condyles. Clenching and manual elevation with a unilateral posterior pivot created jaw tipping. Posterior premature contacts did

not increase joint-loading as much as did loss of posterior tooth support. A wide range of condylar loading could occur during unilateral biting and chewing at the second molar.

J Prosthet Dent 56:478, 1986.

## RADIOGRAPHIC SIGNS OF TEMPOROMANDIBULAR JOINT DISEASE

Christiansen EL, Thompson JR, Kopp SFO, Hass AN, Hinshaw Jr, DB

Classical radiographic signs of joint disease such as reduction of joint space, subcortical sclerosis, and flattening of the lateral part of the condyle have been found to be intercorrelated and frequent among patients with crepitus, pain, and joint dysfunction. The purpose of this investigation was to depict and inter-relate the multiple osseous changes that take place in degenerative TM joints.

Forty-six patients were selected for retrospective study. They included 11 males and 35 females ranging in age from 15 to 73 years who had reported osseous degenerative changes in the TMJ. All patients were scanned with General Electric 8800 scanner with careful supine positioning for true axial plane images. Eighteen to 20 sections were made in five to six minutes using rapid scanning techniques with the mouth closed. All sections were filmed for soft tissue and bone detail.

Bilateral radiographic changes were found in 24 of the 46 patients (52 per cent). The severity of temporomandibular joint radiographic changes, graded as mild, moderate, marked or severe, was found to be positively and significantly correlated to age. Osteophytosis was associated strongly with sclerosis. Condylar angulation was positively and significantly correlated with age.

The findings suggest that the characteristic radiographic signs of degenerative TMJ disease now should include not only sclerosis, osteophytosis, and decreased joint space but also decreased transverse condylar dimension, increased condylar angulation, and an increase in height of the coronoid process.

Dentomaxillofac Radiol 14:83, 1985.