Regeneration of the mandibular condyle after unilateral condylectomy and myotomy of the masseter in lambs

We investigated the degree of regeneration of the mandibular condyle after unilateral condylectomy and myotomy of the masseter in growing lambs. Four 10-week-old lambs had unilateral condylectomy and myotomy of the superficial layer of the masseter on the right side, and were killed 3 months later. The joints were examined radiologically and histologically. All joints showed poor regeneration of the condylar head. In the medial plane there was partial condylar and articular cartilage reformation, but in the lateral plane there was neither condylar nor cartilaginous reformation. The articular cartilage of the temporal bone was thicker in the medial plane and the disc was thicker in the central plane, than in unoperated joints. We conclude that unilateral condylectomy and myotomy of the masseter in the growing period results in poor regeneration of the condyle.     

Use of conservative condylectomy for treatment of osteochondroma of the mandibular condyle.

PURPOSE: The aim of the present study was to present a conservative condylectomy technique (condylectomy performed below the condylar head but high in the condylar neck) and articular disc repositioning as the surgical treatment approach for management of osteochondroma of the head of the mandibular condyle. PATIENTS AND METHODS: Six patients (4 females and 2 males) with an average age of 22.3 years (range, 13 to 32 years) and with an osteochondroma of the mandibular condyle were treated with conservative condylectomy. The remaining condylar neck stump was recontoured, and the articular disc was repositioned and stabilized over the "new" condyle. Any indicated orthognathic surgical procedures were then performed to optimize occlusion, function, and aesthetics. Clinical and radiographic evaluation was performed before surgery (T1), immediately after surgery (T2), and at the longest follow-up (T3). RESULTS: Average follow-up for the patients was 51 months (range, 22 to 108 months). No recurrence of the tumor was encountered in any of the cases. Subjective and objective evaluations of postsurgical temporomandibular joint function and range of mandibular motion were normal. Associated maxillary and/or mandibular orthognathic procedures were found to be stable in the long term. CONCLUSION: Conservative condylectomy with recontouring of the residual condylar neck to function as a condyle and repositioning of the articular disc is a viable option for treatment of osteochondromas of the mandibular condyle. The use of this method of treatment permits effective removal of the tumor and eliminates the need for autogenous grafts or total joint prostheses for temporomandibular joint reconstruction.     

Unilateral mandibular condylectomy in lambs.

The purpose of this experimental study was to investigate the degree of regeneration of the mandibular condyle after unilateral condylectomy in 10-week-old lambs. The lambs were killed three months after the operation, and the joints examined radiologically and histologically. Scoring systems were used to assess the radiological changes and histological regeneration of the condyle. All joints showed regeneration of the condylar head postoperatively. The maximum degree of regeneration occurred on the medial side rather than the central or lateral areas. There was a significant correlation among the medial, central, and lateral planes (P<0.05). The reformed articular cartilage was irregular and thin (P<0.01), and the disc was thick in the central plane (P<0.01) compared with the control joints. The temporal bone was normal. This study shows that unilateral condylectomy in the growing period results in some condylar regeneration particularly on the medial side and reformation of some irregular and thin articular cartilage.     

Large osteochondroma of the mandibular condyle treated by condylectomy using a transzygomatic approach

This article presents an interesting case of osteochondroma of the mandibular condyle with multiple projections in a 42-year-old man. Owing to the large size of the lesion, surgical condylectomy was performed using a transzygomatic approach.     

Clinical course of masticatory function recovery following arthrocentesis in patients with unilateral mandibular condyle head fracture

The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm², p = 0.01; 3 months: 2.90 ± 1.36 mm², p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval.     

A comparative study of unilateral dislocated mandibular condyle fractures in the rabbit.

PURPOSE: The purpose of this study was to clarify the influence of patients age and the degree of dislocation on the healing of mandibular condyle fractures. MATERIAL AND METHODS: Sixty-two Japanese white rabbits (30 adolescent and 30 adult ones) were used. They underwent unilateral condylar neck osteotomy. The proximal fragments were positioned differently. In group I animals, the fragments were reduced into the original position, in group II animals the small fragment was dislocated 55-90 degrees to the ramus. In group III animals the proximal fragment was dislocated 135 degrees to the ramus. Gross and microscopic assessment was performed 4, 6, 8, 12 and 24 weeks postoperatively. RESULTS: In adolescent animals, complete healing of the fracture was observed, irrespective of the degree of dislocation. In the adult animals, there was complete healing of the fractures in groups I and II. In group III animals, there was a decrease of ramus height accompanied by some fibro-cartilaginous changes. CONCLUSION: Even in rabbits condylar deformation has been found following heavily dislocated artificial condylar fractures in adult animals. This result will help to decide for or against surgical treatment of condylar fractures in humans.     

Transmigrant mandibular canines.

PURPOSE: The aim of the present study was to investigate the patterns of transmigrant mandibular canines, the incidence and classification of transmigrant canines, and the associated pathology of these teeth. PATIENTS AND METHODS: This retrospective cohort study was composed of 4,500 panoramic radiographs of patients who presented to our Oral and Maxillofacial Surgery Services from January 1998 to December 2005. Panoramic radiographs were reviewed. Observations were made on the status of missing permanent mandibular canines, retained deciduous canines, side and number of transmigrant canines, gender and age of patients, and any other associated pathology. RESULTS: In the present study, a total of 15 patients had transmigrated canines-6 females (ages 13-33 years) and 9 males (ages 13-57 years). All transmigrant canines were unilateral. Two canines were impacted in the mandible enveloped in cystic lesions. The rest of the transmigrated canines were in varying stages of intraosseous travel and positioning within the mandible, with no pathological entity. CONCLUSION: The use of a panoramic radiograph is imperative and is recommended for discovering such rare malpositions. If the mandibular canine that has migrated across the mandible is associated with pathology, it may be removed. Otherwise, it should be kept under observation.     

Osteoid osteoma in mandibular condyle.

A 21-year-old Japanese woman presented with trismus and spontaneous pain (especially at night) around the left temporomandibular joint. Radiographic examination showed a subcortical sclerosed nodule measuring approximately 8 mm in diameter on the infero-lateral aspect of the left mandibular condyle. Amputation of the condyle was performed under general anesthesia. The patient has been in good condition 8 years postoperatively. The histopathology of the specimen consisted of actively proliferating osteoblasts mixed with an interlacing network of woven bone and osteoid trabeculae. Histopathological diagnosis was osteoid osteoma.     

Region-specific bone mass changes in rat mandibular condyle following ovariectomy

The effects of estrogen deficiency on the mandible have been indicated; however, there have been only a few reports on the mandibular condyle. To clarify the region-specific changes of condyles following estrogen deficiency, we histomorphometrically studied the anterior and posterior regions of condyles in sham-operated (Sham) and ovariectomized (Ovx) female Fischer rats, since it has been reported that rat occlusal force loads mainly onto the anterior part of the condyle. The anterior and posterior regions of condyles showed significantly different bone dynamics. The bone volume in the anterior region of the Sham group increased to 79.9% with aging, but that of the posterior region remained at ca. 60%. In the Ovx group, the bone volume of the posterior region significantly declined to 42.7% until 60 days post-ovariectomy, although no changes occurred in the anterior region. As compared with the Sham counterparts, both regions of the Ovx group showed high bone turnover and revealed significantly low bone volume at 60 days (p < 0.01). Regional differences between anterior and posterior regions were more emphasized in the Ovx than in the Sham group. The osteoclast number and amount of eroded surface in the Ovx were higher in the posterior than in the anterior region, with significance at 30 and/or 60 days (p < 0.05). The mineralized surface at 14 days and the bone formation rate at 60 days in the Ovx posterior region were significantly lower than those in the Ovx anterior region (p < 0.05). Consequently, a net bone loss occurred in the posterior region of the mandibular condyle in ovariectomized rats, owing to region specificity and estrogen deficiency.     

Pseudocysts of the mandibular condyle.

The panoramic radiographs of 507 consecutive patients receiving comprehensive dental treatment were evaluated for the presence of radiolucencies in the mandibular condyles. Nine patients met the study criteria. Five patients had bilateral and four patients had unilateral circumscribed radiolucencies in the anterior aspect of the condyle. Computerized tomography confirmed that these radiolucencies were age-related anatomic variants that were accentuated and distorted during panoramic radiography.     

Osteoma in mandibular condyle

A case of peripheral osteoma occurring in the mandibular ramus in a 26-year-old man is reported. Radiographic examination revealed a pedunculated, protruding globular, bone-like opaque mass around the notch of the right mandibular ramus. Histopathological examination showed a lamellar bone structure with irregular arrangement. Wide trabeculae, narrow interstitial areas, and many fibrovascular channels were detected by scanning electron microscopy. Thus, characteristic findings of a compact osteoma were obtained clinically and histopathologically.