Steven B. Aragon

Estrogen receptors in the temporomandibular joint of the baboon (Papio cynocephalus): An autoradiographic study☆

Using an autoradiographic method, the temporomandibular joint (TMJ) complex of five aged female baboons was studied for the presence of receptors for estradiol-17 beta. The study was performed in an effort to learn more of the pathophysiology of this joint and in an attempt to provide a scientific basis to explain the reported preponderance of women who seek and undergo treatment for signs and symptoms referable to the TMJ. This experiment revealed that the TMJ complex contains numerous cells with receptors for estrogen, particularly the articular surface of the condyle, articular disk, and capsule. Muscles of mastication contained relatively fewer receptors. As a result, one may postulate a role for the sex steroid hormones in the maintenance, repair, and/or pathogenesis of the TMJ. Additional studies are necessary to fully determine the significance of hormone receptors in this site and any correlation between diseases of the TMJ and the endocrine status of affected patients.

Comparative study of alloplastic materials for temporomandibular joint disc replacement in rabbits

Young adult, white New Zealand rabbits underwent either sham surgical procedures or discectomy. In the animals that underwent discectomy, either reinforced silicone or polytetrafluoroethylene-aluminum oxide (PTFE-Al2O3) implants were placed in the glenoid fossa. During gross sectioning, the silicone implants could be easily displaced from the specimen, while the PTFE-Al2O3 implants were firmly anchored. Histologically, fragmentation of the implants was seen in the silicone group; 21.4% of the implants placed were torn. Foreign body giant cell reactions reached a peak after eight weeks. Associated fibrosis and foreign body giant cell reactions were seen, resulting in a thickened capsule and resorption of the condyle and articular fossa. In the PTFE-Al2O3 group there was marked osteoclastic activity, with resorption and severe degenerative changes in both the condyle and glenoid fossa. The foreign body giant cell reaction was severe at all time intervals and increased with time. Tearing of the implant was observed in 46.2% of the joints. These results indicate a need for further evaluation of these materials as disc replacements in humans.

The effects of orthognathic surgery on mandibular range of motion.

A prospective study of 55 orthognathic surgical patients was done to determine the effects of surgery on mandibular range of motion. None of the patients had oral physiotherapy during the course of the study. Nineteen patients had mandibular osteotomies, 21 had maxillary osteotomies, and 18 had two-jaw operations. Maximal interincisal opening (MIO), right and left lateral excursion, and protrusive measurements were obtained preoperatively and at six or more months following surgery. MIO was significantly reduced in both categories of mandibular osteotomies. A sagittal split osteotomy to advance the mandible was associated with the greatest mean reduction of 29%, while a vertical subcondylar osteotomy to set the mandible back had a mean reduction of 10%. Likewise, decreases in MIO were noted with combined surgical procedures. Le Fort I and sagittal split osteotomies were associated with a mean decrease in MIO of 28%, while Le Fort I and vertical subcondylar osteotomies had a mean decrease of 9%. Minimal change in MIO were noted with isolated maxillary osteotomies. These results are similar to the findings of other investigators and indicate the critical need for a sound postoperative rehabilitation program following orthognathic procedures to prevent hypomobility.

Masticatory dysfunction with rigid and nonrigid osteosynthesis of sagittal split osteotomies

T emporomandibular joint and masticatory muscle dysfunction prior to and following bilateral sagittal split osteotomy (BSSO) of the mandible is not well documented. The effect, if any, that the type of internal fixation used has on dysfunctional symptoms is unclear. Several authors have concluded that the TMJ does not appear to be affected following a BSSO with wire osteosynthesis. 1-S However, Freihofer and Petresevic? noted that 16 of 38 patients experienced TMJ clicking after a BSSO advancement of the mandible with wire osteosynthesis. One patient reported pain in one joint, which radiographically displayed signs of arthrosis. Schendel and Epker,’ in a multi-institutional study, documented TMJ noise in 12 of 7 1 patients and TMJ pain in one after BSSO advancement. They concluded that there was no increased

Mandibular range of motion with rigid/nonrigid fixation

Decreased mandibular range of motion that followed orthognathic surgery and that was treated by wire osteosynthesis and 6 weeks of maxillomandibular fixation (MMF) has been previously documented. The present study evaluated maximum interincisal opening (MIO) in 49 subjects undergoing a bilateral sagittal ramus osteotomy (BSRO) with advancement or a BSRO with advancement and a concomitant LeFort I maxillary osteotomy with the patients having either rigid or nonrigid fixation. The group with rigid fixation had early function and mild physiotherapy. The nonrigid group had wire osteosynthesis, MMF that was maintained for 6 weeks, and no postoperative physiotherapy. Patients who underwent a BSRO with rigid fixation experienced a 3.5 mm decrease in MIO (6.9%). Those who had a BSRO and a LeFort I osteotomy with rigid fixation had a 3.3 mm decrease in MIO (6.6%). In contrast, nonrigidly fixed BSRO subjects had a 16.8 mm decrease (29.6%), while those who underwent a combined BSRO and LeFort I osteotomy had a 13.9 mm decrease (26.1%). This study showed that rigid fixation combined with early function and mild physiotherapy resulted in improved MIO postoperatively, as compared to the MIO in a group in which these treatments were not used.

CHONDROSARCOMA OF THE JAWS: CLINICAL FINDINGS, HISTOPATHOLOGY, AND TREATMENT

Three cases of chondrosarcoma involving the jaws are presented, one in the maxilla and two in the mandible. The salient points of clinical presentation elucidated by this series of cases are that a widened periodontal ligament space is present in chondrosarcomas as well as in osteosarcomas, and that a slowly increasing diastema may be the earliest clinical sign. The most important lesson to be learned from the histopathology is that one should not accept a diagnosis of a benign cartilaginous tumor of the jaws. Treatment of these lesions should consist of wide surgical excision and consideration of adjunctive or palliative radiotherapy, especially in the maxilla. It should also be noted that recurrences may develop 10 to 20 years later, and follow-up should be lifelong.

Rigid fixation of maxillary osteotomies: A preliminary report and technique article

The authors review their experiences with seventy cases of maxillary osteotomy rigidly stabilized with bone plates and minimal or no maxillomandibular fixation. The surgical technique, which allows consistent placement of plates in dense bone without endangering root apices, is described in detail. Orthodontic management has been started as early as 3 weeks postoperatively. A disadvantage of small plates is the possible need for their removal, which requires a second surgical procedure. Plates have been removed or replaced in five patients in this series.

Modified sagittal split technique for patients with a high lingula

Unfavorable fractures of the proximal fragment during the sagittal ramus split procedure, although uncommon, occur with an incidence ranging between 3% and 6.6%. One anatomic feature that may predispose to an unfavorable fracture is a thin mandibular ramus in the region of the medial osteotomy. One particular situation that can increase the risk of an unfavorable fracture is a lingula that is situated very high on the mandibular ramus. Even in a normal-sized mandibular ramus, a high lingula places the medial cut in a thin region where there is little or no cancellous bone. The technique presented is a modification of the sagittal split osteotomy which can assist the surgeon in preventing an unfavorable fracture should an unusually high lingula or a thin ramus be encountered.

Monocular blindness developing 7 days after repair of zygomaticomaxillary complex fracture. A clinical report.

Blindness following zygomaticomaxillary complex (ZMC) fracture and surgical repair is an unfortunate and uncommon complication. A review of the literature reveals fewer than 25 cases of monocular blindness resulting from zygomaticomaxillary fracture or repair. The case presented here is that of a man who was assaulted with a baseball bat and suffered a mildly displaced ZMC fracture. On admission, the patient had light perception only in his left eye. During his convalescence, vision in his left eye gradually improved to the point of allowing him to read a newspaper without difficulty. Then, 9 days after the injury (7 days after surgical repair), the patient awoke with complete blindness of the left eye. The possible mechanisms for such loss of vision are discussed.