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Soft tissue changes following correction of mandibular hyperplasia were studied using a laser system for three-dimensional (3-D) surface measurement. Twelve subjects (7 men and 5 women; age 17-48 years) were included in this study. Bilateral sagittal split ramus osteotomies were performed in ten patients and intraoral vertical ramus osteotomies in two patients. Pre- and postoperative images, obtained with the laser system, were superimposed to determine distribution of changes in the perioral soft tissue. Mean volume changes were 1032.3 mm^3 in the Subnasale-UL area and 8700.9 mm^3 in the LL-Menton area. Changes in both areas were symmetrical around the mid-sagittal plane in some patients and asymmetrical in others. This measurement system provided a simple method of determining 3-D changes in soft tissue following surgery and might be useful for clinical purposes.

Skeletal stability during the first year after mandibular advancement surgery and fixation using biodegradable selfreinforced poly-l-lactide (SR-PLLA) screws, without postoperative intermaxillary fixation, was studied in 25 patients by means of cephalometric measurements. The magnitude of advancement was on average, 3.88 mm at pogonion (PG) (range 1.25-6.5 mm) and 4.57 mm at B-point (range 2.75-7.5 mm). After one year a mean relapse backwards of 0.59 mm at the PG (15%) and 0.78 mm at the B-point (17%) was observed. Nineteen patients (76%) and 17 patients (68%) were stable at PG and B-point, respectively. SR-PLLA screws are considered to be comparable to other forms of rigid internal fixation for fixation of bilateral splitting osteotomies after mandibular advancement, as far as skeletal stability is concerned.

The response of the entire facial soft tissue to correction of mandibular hyperplasia was evaluated in 25 patients by moire topography. Postoperative changes were quantitatively analyzed by a computer-aided superimposition technique. Posterior displacements occurred in the lower third of the face. A marked retraction was observed around the chin, but the changes gradually decreased in the coronal and posterior directions with distance from the chin. The upper lip was slightly reduced; however, no direct effect was found in the cheeks. The results of this study constitute a database that, if used in conjunction with an interactive imaging system, would allow surgeons to predict accurately the postoperative appearance of the patient.

Twelve patients with 13 mandibular fractures following third molar extraction were treated in our Department between 1980 and 1995. Clinical and radiographic data relating to these patients were analysed retrospectively to determine complication characteristics. Only one fracture occurred during surgery. The first week after the operation was found to be most critical for fracture occurrence. A ''cracking'' sound from the jaw while eating frequently indicated that a fracture had occurred, but repeated radiographic examination may be necessary for definitive diagnosis. Most teeth removed belonged to Groups II/III according to Pell & Gregory's classification^1^6, indicating partial or total impaction of the tooth and a narrow space in the retromolar triangle. In all cases, tooth roots were superimposed on or adjacent to the inferior alveolar canal. Clinically, the age of the patient seemed to be a common predisposing factor, and patients older than 30 to 40 years were considered to be a risk group. Regardless of the degree of impaction and tooth position, the fracture type seen was uniform, i.e. preangular location and a typical course of the fracture line. After adequate fracture treatment, no further complications were noted.

Synovial chondromatosis (SC) is an uncommon, benign condition of unknown etiology. A case of SC of the temporomandibular joint (TMJ) with the immunohistochemical findings of transforming growth factor-@b (TGF) and tenascin (TN) is reported. The roles of TGF and TN in SC of TMJ are discussed.