A longitudinal study of the effect of experimental osteoporosis on bone trabecular structure in the rat mandibular condyle.

The authors performed a longitudinal study of the microstructural changes occurring in the mandibular condyle during osteoporosis using the findings obtained from micro-CT. The subjects used in this study were eight Sprague-Dawley rats. Among them, five were administered the immunosuppressant drug FK506 by injection for five weeks, while the other three were administered saline solution in the same manner. Micro-CT images were taken of the bilateral mandibular condyle, hip, and knee joints in all animals on days 1, 8, 15, 22, 29, and 36 following injection. Six indices of morphometric analysis were compared between the two groups. Significant differences were observed in BV/TV, Tb.Th, Tb.N, and Tb.Sp in the mandibular condyle, while trabecular bone density appeared to decrease in the immunosuppressant group on three-dimensional (3D) imaging. And, in comparison with the mandibular condyle and femur, they were similar. These results suggested that osteoporosis affects not only the femur, but also the mandibular condyle.

Morphological observation of process of mouse temporomandibular joint formation.

The aim of this study was to clarify the developmental mechanism of the temporomandibular joint (TMJ) cavity, using the relationship between Meckel's cartilage and the mandible to morphologically observe the process of TMJ formation in mouse fetuses. We investigated the involvement of apoptosis in the development of the mouse TMJ cavity. We attempted to 3-dimensionally clarify the developmental process of the mandible and Meckel's cartilage by observing the developmental process optically and reconstructing 3-dimensional images to observe 3-dimensional locations of the mandible and Meckel's cartilage. Formation of the upper joint cavity began on embryonal day 16, and a complete joint cavity was formed on embryonal day 18. Formation of the lower joint cavity began on embryonal day 18, and formation was almost completed on embryonal day 19. Meckel's cartilage adjacent to the mandible decreased with development of the mandible but was vestigial on embryonal day 19. The posterior region of Meckel's cartilage developed toward the posterior direction, and it was 3-dimensionally confirmed that the mandible and Meckel's cartilage were separated. Histological observation by the TUNEL method revealed the presence of solitary and diffuse apoptotic cells not only in the joint cavity, but also around the condyle.

Vertical fracture of mandibular condyle treated with intra-articular pumping therapy: a case report.

We report a patient with vertical fracture of the mandibular condyle visualized by computed tomography (CT). A 43-year-old woman visited our department the day after the injury occurred. At the initial examination, she experienced pain in the left temporomandibular joint (TMJ) when opening her mouth. Maximum mouth opening distance was 15 mm. Routine radiography showed normal findings, but CT revealed vertical fracture of the left mandibular condyle. Based on clinical findings, conservative therapy consisting of intra-articular pumping therapy and training for mouth opening was initiated. After 10 days, mouth opening distance increased to 36 mm, and pain in the left TMJ disappeared.

Osteoma of mandibular condyle as cause of acute pain and limited-mouth-opening: case report.

In benign tumors in the mandibular condyle such as osteoma and osteochondroma, symptoms such as pain and limited-mouth-opening are rarely observed. Therefore, these tumors are often detected after the development of changes in occlusion and mandibular midline deviation. We encountered a very rare patient with mandibular condyle osteoma who showed acute pain and markedly limited-mouth-opening.

Cone-beam CT (CB Throne) applied to dentomaxillofacial region.

Cone-beam CT (CBCT) systems specifically designed for hard-tissue imaging of the maxillofacial region have recently become commercially available. The newly-developed CBCT system, CB Throne (Hitachi Medical Corp., Tokyo), is characterized by a number of features such as low dose, sub-millimeter spatial resolution, and a small footprint. This system has been clinically applied at Chiba Hospital, Tokyo Dental College, since April 2005. This article reports the characteristics of this system, and its diagnostic power for maxillofacial lesions and the pre-operative planning dental implants.

Use of a new instrument for lateral release in arthroscopic surgery of the temporomandibular joint: a preliminary study.

We developed a new instrument, which we call a lateral releaser, to improve the safety of either a blind lateral release or lateral stretching within the TMJ We used it during arthroscopic surgery in patients with chronic painful hypomobility of the temporomandibular joint (TMJ). We operated on 24 TMJs in 17 patients (15 women and 2 men). At operation, the mean increase in the interincisal distance was 22 mm (range 10-32). No instruments were broken. No serious surgical complications were reported during or after operation. Many of the patients currently have an interincisal distance exceeding 38 mm.