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The temporalis muscle flap can be used as an inter-positional graft placed into a gap arthroplasty site in temporomandibular joint (TMJ) ankylosis. The purpose of this study was to investigate the role of the muscle graft in sheep. Five pure-bred adult Merino sheep were used and ankylosis was induced in all right TMJs. At 3 months, the ankylosis was released by gap arthroplasty and reconstructed with a masseter muscle graft, because the temporalis muscle is short and poorly vasculized in sheep. The sheep were killed at 3 months after muscle grafting. The maximal mouth opening was recorded before and after operation and at death. The joints were examined radiologically and histologically. In 4 sheep mouth opening remained at the pre-operative level. A clear radiolucent space remained between the smooth temporal and ramus stumps. Histologically, the muscle graft remained vital but with some fibrous tissue formation between the bone ends. One sheep developed an infection at the operative site following the muscle graft; this partly resolved with antibiotics, but the TMJ developed a fibrous reankylosis that was demonstrated clinically, radiologically and histologically. These results indicate that an uncomplicated temporalis muscle graft reconstruction with gap arthroplasty is a successful and stable procedure in human TMJ ankylosis.

We investigated the redox state of albumin in the synovial fluid from patients with temporomandibular joint (TMJ) disorders (TMD) to evaluate the relation between the cause of the TMD and the number of types of oxygen in synovial fluid. The albumin was fractionated into three components, human mercaptalbumin (HMA, reduced form) and two types human non-mercaptalbumin (HNA, oxidized form), by high-performance liquid chromatography (HPLC). The 63 patients were divided into three groups radiologically, and the ratios of the redox state of the synovial fluid in each group were compared. The fraction of HNA was significantly higher in patients with advanced disease than in patients with early disease. This indicates that the TMJ is affected by intra-articlular oxidative stress, and the severity of TMD correlates closely with the number of oxidative factors. Oxidative stress was thought to be responsible for the genesis of TMD.

Our aim was to examine the short-term effect of combined treatment with single arthrocentesis and a COX-2 inhibitor on 26 patients with severe symptoms of temporomandibular joint (TMJ) disorders. The severity of the disorders was graded according to the degree of restriction of mouth opening and pain score on a visual analogue scale. Synovial fluid was collected from the superior joint space of the affected TMJ, and arthrocentesis was done with isotonic saline, 200ml. Subsequently, etodolac, 400mg/day, was given for 2 weeks. At 14 days, patients were re-examined and further specimens of synovial fluid were collected. Patients generally lost their symptoms and the severity of the disorders improved significantly (P<0.01). The concentrations of total protein and albumin in synovial fluid decreased with no statistical significance. However, the concentration of matrix metalloproteinase-3 and its ratios to total protein and albumin did decrease significantly (P<0.05). Our results suggest that a larger controlled study is necessary to clarify the contributory effect of arthrocentesis and etodolac for patients with severe symptoms of TMJ disorders.

The purpose of this study was to investigate the effect of costochondral grafts in the temporomandibular joint (TMJ) in sheep. Five pure-bred adult Merino sheep were used. The condyle alone was resected and replaced with a costochondral graft from the 13th rib. The sheep were killed 3 months after operation. The range of jaw movements before and after operation and at death were recorded. The joints were examined radiologically, macroscopically, and histologically. A new condylar head with normal configuration and function developed. Histologically, the chondrocytes were arranged in a fashion similar to that of a normal joint. All inferior joint spaces showed fibrous adhesions between the condylar head and disc. This study showed that, when such grafts are used to replace the condyle in an otherwise normal sheep TMJ, they fused to the ramus and reconstituted a nearly normal, fully functional joint.

Objective: To determine the relationship between synovial fluid, chondroitin sulfate disaccharide and hyaluronic acid to differing degrees of experimental temporomandibular joint (TMJ) osteoarthritis (OA)., Design: Twenty-four merino sheep were divided into three groups and had different TMJ surgical procedures to produce OA. Group I; control (six sheep), Group II; disc perforation (nine sheep) and Group III; disc perforation and articular damage (nine sheep). Synovial fluid was collected initially and at sacrifice at 3 months. Chondroitin 4-sulfate, chondroitin 6-sulfate and hyaluronic acid were measured and correlated to the OA histologic score., Results: The chondroitin-sulfate levels were significantly increased (Group I to Group II P< 0.001; Group I to Group III P< 0.001), the hyaluronic acid levels decreased (Group I to Group II P< 0.01; Group I to Group III P< 0.01) with the increasing OA score., Conclusion: Chondroitin-sulfate and hyaluronic acid show a correlation with surgically created TMJ osteoarthritis in sheep model., (Copyright 2001 OsteoArthritis Research Society International.)

In order to define and map chromosomal copy number alterations in salivary gland tumors (SGTs), a comparative genomic hybridization (CGH) technique was applied to two pleomorphic adenomas (PAs), one adenoid cystic carcinoma (ACC), and one basal cell adenocarcinoma (BCAC). The PAs exhibited regional copy number losses at 5q12.4-q14.1, 9q12-q21.13, and 16q11.2, as well as a gain at 20p12.1; among these, the losses at the 9q12-q21.11 and 16q11.2 regions were common to both PAs. The ACC showed overrepresentations of the entire regions of chromosomes 16 and 20, a regional gain at 22q12.3-q13.1, and no losses. In the BCAC, regional gains at 9p21.1-pter, 18q21.1-q22.3, and 22q11.23-q13.31 as well as losses at 2q24.2 and 4q25-q27 were seen; the gain at 22q12.3-q13.1 was common in both the ACC and the BCAC. These CGH data indicate that different genetic alterations are present in the different types of SGTs, and that the alterations involve several chromosomes. The discovery of common alterations in the same and/or different types of tumors might be important in the understanding of the development and progression of the SGTs.

We measured matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMP) in temporomandibular joint (TMJ) disorders. All patients were fully investigated, by visual analogue pain scores, plain radiographs and double-contrast arthrotomograms. The patients were grouped according to whether or not they were in pain. There were 35 patients with painful joints; 16 painless crepitating joints and 10 with chronic closed locked joints. A further group of 9 volunteers with no symptoms of TMJ abnormalities were used as controls. We found that synovial fluid concentration of MMP-3 was significantly increased (1117.2 (164.0) ng/ml) (P< 0.05) in the painful group compared with controls (436.2 (94.8) ng/ml) and with the two groups with painless TMJ (475.0 (113. 0) ng/ml/crepitation, and 516.0 (115.1) ng/ml/closed locked joints). MMP-1 and TIMP-1 were not recordable in most joints, and the serum concentrations of MMP-1, MMP-3, and TIMP-1 were similar to those in controls in all groups. There was no correlationship between MMP-3 concentration and joint morphology as shown by plain radiographs and double contrast arthrotomograms. These findings indicate that the synovia of painful joints are inflamed., (Copyright 2000 The British Association of Oral and Maxillofacial Surgeons.)

The purpose of this study was to investigate the effect of limited movement of the jaw on ankylosis of the temporomandibular joint (TMJ). Eighteen adult sheep were divided into two groups. In Group 1, the temporal and condylar articular surfaces were removed together with the disc on the right. In Group 2, we did the same procedures but in addition the jaw movements were limited by a wire. One sheep was killed just after the operation, four at one month, and four at three months, in each group. The range of jaw movements preoperatively and at the time of death were recorded. The joints were examined radiologically, macroscopically, and histologically. We used a scoring system to assess the radiological changes and histological extent of ankylosis. At one month, the joint spaces were filled with fibrous tissue, but a small joint space existed in all four joints in Group 1. In Group 2, there was full ankylosis in two joints and partial ankylosis in two joints. At three months, similar ankylotic changes were seen in both groups. The histological score for ankylosis at one month showed that those in Group 2 were significantly more ankylosed than in Group 1 (P<0.01). The range of jaw movements was more limited at one month in Group 2, both vertically and to the left, and was significantly decreased in both groups (P<0.01) at three months. Limitation of jaw motion hastens the progress of TMJ ankylosis., (Copyright 2000)

Unilateral condylectomy was performed on five young adult sheep. The animals were killed at three months and both joints and the excised condyles were examined macroscopically and histologically. All five showed pronounced regeneration of the condylar head on the operated side. The articular surface was fibrous and fused to the disc. Four of the five opposite joints showed medial remodelling. Young sheep have a higher regenerative capability than human adults of equivalent age, and similar reactions to those of children.

Objective: The purpose of this study was to determine the role of the disk in intraarticular ankylosis of the temporomandibular joint., Study Design: Twelve adult sheep were divided into 2 groups. In group 1, removal of the temporal and condylar articular surfaces was performed on the right temporomandibular joint and the disk was maintained; in group 2, removal of the articular surfaces and diskectomy were performed on the right temporomandibular joint. One sheep from each group was killed just after surgery and 5 sheep from each group were killed at 3 months. The joints were examined radiologically, macroscopically, and histologically. The range of jaw movements was recorded preoperatively and at sacrifice., Results: Each of 2 sheep in group 2 had lost 4% of their body weight by 3 months; all of the other sheep maintained or increased their weight. The range of jaw motion to the right was significantly lower in group 2 than in group 1 (P<.01). In group 1, fibrous repair of the articular surface and regeneration of the condylar head was seen. In group 2, each of the joints showed a total fibrous ankylosis with some calcification. There was a statistically significant difference in radiologic score between the groups (P<.0001). Histologic scores for group 1 demonstrated significantly lower scores on the degree of ankylosis scale and degree of calcification scale (P<.0001)., Conclusions: This study showed that the presence of the disk prevented the development of fibrous intraarticular ankylosis of the temporomandibular joint.

Purpose: The purpose of this experimental study was to evaluate the initial effect of a frozen-stored disc allograft on the osteoarthritic sheep temporomandibular joint (TMJ)., Materials and Methods: Bilateral osteoarthritis was induced in the TMJ of four sheep. Three months later, unilateral discectomy and frozen-stored disc allograft replacement were performed. The donor disc had been obtained from a healthy animal at killing. The disc was stored in a deep freezer at -70 degrees C for 1 month and thawed just before grafting. The contralateral joints were undisturbed and served as a control at 3 months. At 6 months after the initial procedure, 3 months after the repair, the four sheep were killed., Results: All four grafted discs were perforated and displaced. In the repaired joints, the condylar articular surface was partly denuded in some areas, and part of the surface showed fibrous repair. The control joints showed osteoarthritic changes., Conclusion: Frozen-stored disc allograft is not a satisfactory interpositional material in the osteoarthritic sheep TMJ.

Purpose: The purpose of this study was to test the effect of repeated injections of hyaluronic acid (HA) on the sheep model of osteoarthrotic temporomandibular joint (TMJ) disease., Materials and Methods: Bilateral osteoarthrosis (OA) was induced in the TMJs of six sheep. HA was injected into one joint on 7, 10, 14, 17, and 21 days postoperatively. Normal saline was injected into the contralateral joint. Three sheep were killed at 1 month and 3 at 3 months. The joints were removed and examined macroscopically and histologically. A special scoring system was applied following the modified Mankin's score to evaluate the histologic changes., Results: The control group showed severe osteoarthrotic changes in the condyle, deviation in form from normal morphology, and marked marrow fibrosis. The HA-treated group showed less deviation from normal condylar morphology. The histologic scores at 1 month were HA 12.6, control 24.2 (P < .001), and at 3 months were HA 6.9, control 18.9 (P < .001). There was a significant difference in osteoarthrotic changes between HA-treated and control TMJs, with the HA-treated TMJs having less severe changes., Conclusion: Repeated intraarticular injections of HA into a sheep TMJ with experimentally induced OA minimizes the extent of osteoarthrotic change when compared with the control joint. Thus, HA may have a role in preventing the progression of TMJ OA.

A simple and easy cryosurgical method to treat intraoral mucous cysts is described. Twelve female and six male patients, with mucous cysts on the lower lip and the tip of the tongue, were treated by direct application of liquid nitrogen with a cotton swab. Each lesion was exposed to four or five cycles composed of freezings of 10-30 s and thawings of double the freezing times. No anesthesia was required. All lesions had disappeared completely 2-4 weeks after one or two treatment courses of cryosurgery. In all cases, neither scarring nor recurrence was noted during the 6 months to 5 years of follow-up.

The effect of surgically perforating the mandibular condyle to allow synovial fluid to contact the marrow was examined in 5 sheep temporomandibular joints. The surgical defect showed replacement of the marrow with fibro-osseous tissue and subcortical cysts. A vertical, central osteophyte emerged from the perforation, causing attenuation or perforation of the disc and temporal surface proliferation. These changes were radiographically and histologically similar to advanced osteoarthritis. This supports the concept that intraarticular micro or macrofracture may result in osteoarthritis.