ABSTRACT
Objective@#To summarize the clinical manifestation and treatment of temporomandibular joint (TMJ) disc ossification, providing reference for clinical diagnosis and treatment of TMJ disc ossification.@*Methods@#From January 2006 to January 2018, 4 patients with TMJ disc ossification (2 males and 2 females, aged 20-55 years with an average age of 35.5 years) which were admitted to the Department of Oral and Maxillofacial Surgery, Shenzhen Second People′s Hospital were analyzed retrospectively. Ossification of TMJ disc was found in 4 cases during TMJ surgery. Two cases underwent partial ossification resection plus disc reduction and anchorage, and two cases underwent discectomy plus temporalis myofascial flap replacement. The causes, clinical manifestations and surgical effects of TMJ disc ossification were analyzed by comparing the maximal interincisal opening, visual analogue scale (VAS) score and MRI imaging indexes before and after operation.@*Results@#The history of anterior disc displacement of TMJ in 4 patients was long (average 11.5 years). In clinic, TMJ disc ossification was characterized by TMJ pain and limitation of mouth opening. The maximal interincisal opening was (32.1±6.1) mm and the VAS score was (7.3±0.4) before operation. MRI showed that the displaced discs of the affected sides were displaced and the condyle bones were worn. During the operation, ossification of TMJ discs was found yellow and hard, and the original elasticity was lost. Pathologic findings showed that the TMJ disc cartilage were ossified to osteoid tissue. Under the microscope, bone cells scattered around the bone cells and red trabecular bone were seen, and there were bone trabecula formed. In a follow-up of one year, TMJ pain was significantly decreased [VAS: (1.7±0.2)], and the maximal interincisal opening was (38.5±2.2) mm. MRI showed that the TMJ disc returned to normal position, and the sign of repairing and reconstruction of condyle bone could be found.@*Conclusions@#Long term displacement of TMJ disc may cause ossification with pain and limitation of interincisal opening. According to the degree and extent of ossification, partial ossification plus disc reduction and anchorage or discectomy plus temporalis myofascial flap replacement is feasible, and the clinical effects are satisfactory.
ABSTRACT
BACKGROUND:Overproduction of thyroid hormones is shown to increase the activities of osteoblasts and osteoclasts, stimulating bone resorption and transformation. Inadequate compensation of increased bone resorption by bone transformation results in an increased loss of bone mass. OBJECTIVE:To investigate the effects of hyperthyroidism on the density of the alveolar bone. METHODS:Twenty-four New Zealand rabbits were equal y randomized into hyperthyroidism group and control group. Rabbits in the hyperthyroidism group or control group were daily injected intraperitoneal y with 50μg/kg levothyrocine diluted in physiological saline solution or equal volume of physiological saline. At 8 weeks after treatment, serum levels of thyroid hormones (FT3 and FT4), alkaline phosphatase, magnesium and calcium, phosphorus were determined;meanwhile, the bone densities of the lumbar vertebra, mandible, bilateral distal femur were determined by dual energy X-ray absorptiometry and the correlation analysis was performed. RESULTS AND CONCLUSION:At 8 weeks after treatment, serum levels of FT3, FT4, alkaline phosphatase calcium, phosphorus, and magnesium in the hyperthyroidism group were significantly increased (P<0.01), while the bone densities of the lumbar vertebra, mandible, bilateral distal femur were significantly decreased (P<0.05), compared with the control group. Bone density of the mandible was positively correlated with the bone density the lumbar vertebra and bilateral distal femur. These findings suggest that the changes in FT3 and FT4 are sufficient for the diagnosis of hyperthyroidism. Hyperthyroidism results in the decreased density of the alveolar bone, indicating the occurrence of osteoporosis.