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

The effect of extracapsular injuries on growth and development of the mandible condyle: an experimental study in growing dogs

OBJECTIVE

To investigate the effects of condylar extracapsular injuries on the development of the mandibular condyle and try to find a way to treat condylar hyperplasia by electively using such injuries to restrict the overdeveloped mandibular condyle.

STUDY DESIGN

Sixty 6-month-old beagle puppies were divided randomly into five groups: blank control; unilateral fracture to the condylar neck; unilateral fracture to the condylar neck treated with rigid internal fixation; unilateral periosteum injury; unilateral decortication of the condylar neck. Computed tomography, ^{99 m}Tc single-photon emission computed tomography, and tetracycline-calcein double-labeling were performed after surgery. The puppies were sacrificed 12 and 24 weeks after surgery. Morphologic analyses and examination of growth activity were done.

RESULTS

Unilateral fracture of the condylar neck without fixation caused local morphologic changes during the early postoperative period, but compensatory growth of the condyle altered such changes after healing. The other types of injury failed to inhibit the growth of the condyle and the mandible, whereas functional deviation of the chin was found after unilateral fracture of the condylar neck with or without fixation.

CONCLUSIONS

The four types of extracapsular injury described here failed to inhibit the growth of the mandibular condyle and could not be selected as alternatives to treat condylar hyperplasia.

Effect of surgical repair of the joint capsule in mandibular condyle fractures in adult rats

PURPOSE

The aim of the present study was to assess histologic changes in the temporomandibular joint (TMJ) of adult rats subjected to unilateral fracture of the mandibular condyle and soft tissue injury.

MATERIALS AND METHODS

The animals were divided into 2 groups: one had surgical treatment for soft tissue repair and the other had no soft tissue treatment. All histologic evaluations were performed according to the presence or absence of synovitis, vascularity, presence or absence of joint inflammation, and presence or absence of the articular disc. The contralateral TMJs also were evaluated.

RESULTS

The results showed few histologic changes in the synovial membrane and joint disc for the 2 groups and in the synovial membrane and disc of the contralateral side, where indirect trauma occurred in the unoperated joint.

CONCLUSION

This study showed that treating or not treating soft tissues does not change the treatment results of condyle fracture or interfere with TMJ pathosis.

Facial symmetry evaluation after experimentally displaced condylar process fracture in methotrexate treated rats

PURPOSE: To investigate the facial symmetry of high and low dose methotrexate (MTX) treated rats submitted to experimentally displaced mandibular condyle fracture through the recording of cephalometric measurements. METHODS: One hundred male Wistar rats underwent surgery using an experimental model of right condylar fracture. Animals were divided into four groups: A - saline solution (1mL/week); B - dexamethasone (DEX) (0,15mg/Kg); C - MTX low dose (3 mg/Kg/week); D - MTX high dose (30 mg/Kg). Animals were sacrificed at 1, 7, 15, 30 and 90 days postoperatively (n=5). Body weight was recorded. Specimens were submitted to axial radiographic incidence, and cephalometric mensurations were made using a computer system. Linear measurements of skull and mandible, as well as angular measurements of mandibular deviation were taken. Data were subjected to statistical analyses among the groups, periods of sacrifice and between the sides in each group (α=0.05). RESULTS: Animals regained body weight over time, except in group D. There was reduction in the mandibular length and also changes in the maxilla as well as progressive deviation in the mandible in relation to the skull basis in group D. CONCLUSION: Treatment with high dose methotrexate had deleterious effect on facial symmetry of rats submitted to experimentally displaced condylar process fracture.

Effects of the condylar process fracture on facial symmetry in rats submitted to protein undernutrition

PURPOSE: To investigate the facial symmetry of rats submitted to experimental mandibular condyle fracture and with protein undernutrition (8% of protein) by means of cephalometric measurements. METHODS: Forty-five adult Wistar rats were distributed in three groups: fracture group, submitted to condylar fracture with no changes in diet; undernourished fracture group, submitted to hypoproteic diet and condylar fracture; undernourished group, kept until the end of experiment, without condylar fracture. Displaced fractures of the right condyle were induced under general anesthesia. The specimens were submitted to axial radiographic incidence, and cephalometric mensurations were made using a computer system. The values obtained were subjected to statistical analyses among the groups and between the sides in each group. RESULTS: There was significative decrease of the values of serum proteins and albumin in the undernourished fracture group. There was deviation of the median line of the mandible relative to the median line of the maxilla, significative to undernutrition fracture group, as well as asymmetry of the maxilla and mandible, in special in the final period of experiment. CONCLUSION: The mandibular condyle fracture in rats with proteic undernutrition induced an asymmetry of the mandible, also leading to consequences in the maxilla.

Open Reduction and Internal Fixation of Dislocated Condylar Fractures in Children

The purpose of this study was to investigate the long-term clinical and radiologic outcomes of treating dislocated condylar fractures sustained in childhood with open reduction and internal fixation (ORIF). Six children 14 years or younger with a condylar neck or subcondylar fracture with dislocation of the condyle from the glenoid fossa were treated with ORIF. Patients were followed for 27 to 92 months post-ORIF (mean: 67.6 months) with routine clinical and radiologic examinations. On the dislocated side, all patients radiographically showed signs of remodeling of the condylar process and shortening of the ramus. Subsequent to their fractures, 3 patients were classified with Angle class II malocclusion, retrognathism, and deviation of the mandibular symphysis. Four patients had objective and/or subjective signs of temporomandibular (TMJ) dysfunction. Until open surgery demonstrates a consistent functional advantage, nonsurgical management should be considered the first treatment option for the dislocated pediatric condylar fracture.

Skeletal changes after experimentally displaced condylar process fracture in growing rats

INTRODUCTION

Fractures of the mandibular condyle are common. A potential for growth disturbances in young individuals has been reported; however, there are few experiments studying such consequences. Skeletal changes after fracture of the condyle in the growing period were analysed in this study.

MATERIAL

Fifty young Wistar rats weighing 100g were used. Under general anaesthesia unilateral fracture dislocations of the condylar process were induced surgically in the experimental group (n=25), while only surgical access was performed in the sham-operated group. The animals were sacrificed at 3 months of age. The mandibles were disarticulated, and radiographs were taken (axial skulls and lateral hemimandibles). Cephalometric evaluations were made using a computer system. Statistical tests were applied between groups and contralateral sides in each group.

RESULTS

There were atrophy and degenerative change of the fractured condylar process. There was also a significant difference in the height of the mandibular body and in the length of anterior and posterior maxilla.

CONCLUSION

It was concluded that an experimental fracture of the mandibular condyle during the growing period in rats induced degenerative changes of the condyle as well as an asymmetry of the mandible, affecting height of the body, also leading to consequences in the maxilla.