Tadashi Sasai

A unique case of desmoplastic ameloblastoma of the mandible: report of a case and brief review of the English language literature.

A unique case of desmoplastic ameloblastoma is reported from the clinical, radiographic, and histologic viewpoints. The patient was a 56-year-old man who complained of a painless swelling on the buccal aspect of the left mandible. Periapical and panoramic radiographs revealed a rounded, slightly radiolucent area with blurred osteosclerotic margins. Occlusal radiograph and computed tomography images disclosed buccal bone expansion outlined by thinned cortices. Computed tomography images exhibited an enhanced area in the anterior portion of the lesion. Interestingly, the coronal computed tomography images revealed a close relationship between the periodontal membrane of the left mandibular second premolar and the enhanced area. Biopsy specimens from the anterior portion of the lesion displayed typical histologic features of the desmoplastic variant of ameloblastoma. However, those from the posterior portion disclosed a large cystic formation. Oxytalan fibers were identified in the stromal tissue of the tumor, which suggested that the tumor arose from the epithelial rests of Malassez in the periodontal membrane of the related tooth. We also reviewed previously reported 41 cases. In 36 of 38 cases in which the location was specified, the tumor was found in the anterior to premolar region of the maxilla or mandible. A radiographic description was given in only 29 previous cases, 28 of which involved multilocular lesions. No cyst as large as the one in the present case was found among the previously reported desmoplastic ameloblastomas. Although the present case deviates from the usual desmoplastic variant of ameloblastoma in terms of locus, radiologic appearance, and cyst formation, it still meets the histologic criteria for this variant in both the stromal and epithelial components.

Magnetic resonance imaging of human mandibular elevator muscles after repetitive maximal clenching exercise

Exercise can enhance the signal intensity (SI) of skeletal limb muscles on T2-weighted magnetic resonance imaging (MRI). The purpose here was to evaluate the effects of repetitive maximal clenching exercises involving the mandibular elevator muscles with T2-weighted MRI. Seven normal volunteers were imaged before and immediately after performing repetitive maximal clenching and at 3, 6, 9, 12, 15, 20 min after the exercise in a 1.5 T GE magnet with spin-echo sequences. SI in the masseter, medial pterygoid and temporalis increased significantly (p < 0.001) and the cross-sectional area (CSA) of masseter increased 10.11% on T2-weighted MRI after exercise. The increased SI and CSA declined approximately to the pre-exercise level in about 20 min after exercise. No SI and CSA changes were found in the inactive neck muscle and no SI changes in the mandibular bone marrow (p > 0.05). The findings suggest that the use of exercise-enhanced MRI might be helpful in the study of the function and dysfunction of muscles in the orofacial region.

The clinicoradiologic predictability of perforations of the soft tissue of the temporomandibular joint

One hundred thirty-one arthrographic examinations of temporomandibular joints were performed on 119 patients. The relationships between clinical symptoms, tomographic findings, and soft-tissue perforation were examined. Perforations of the articular disk or posterior attachment were revealed in 58 joints. Joints with crepitation showed a high frequency of perforation (20 of 22). Pain in the joint area and limitation of opening correlated to disk reduction. Perforations were observed in 12 of 21 joints with continuous pain. Osseous changes were detected in 89 joints. Joints with abnormal radiodensity (erosion, sclerosis) combined with abnormal shape (pocket erosion, osteophyte formation, deformity) showed a high frequency of perforation (41 of 45), which corresponded to 84% in this study. In those cases with osseous change or crepitation, positive predictive values of perforation were both 91%. These types of osseous change and their clinical significance might predict soft-tissue perforation with high accuracy before an arthrogram is performed.

Longitudinal study of patients with TMJ dysfunction by tomographic examination: Condylar position and clinical sign

For patients with TMJ dysfunction, operators often change the condylar position by various methods. The aim of this study is to investigate how much the changes with time of condylar positions are related to the changes of clinical signs.The subjects were 584 joints of 127 patients with TMJ dysfunction to whom the serial lateral TMJ tomography was performed more than twice.In the most of cases where the condylar position had moved downward, inter-incisal distance had increased and TMJ noise had ameliorated. Furthermore, in many cases where the condylar position had moved forward, the amelioration of the TMJ pain was observed.It was considered that those ameliorations occurred because the positional relationship between the condylar head and the articular disk or posterior attachment had been improved.

The Effect of Irradiation-induced Hyposalivation on Dental Caries Induction in Rats Fed High or Low-Sucrose Diet

The effects of X-ray irradiation to the salivary glands on the induction of dental caries were examined in specific pathogen-free Sprague-Dawley rats fed either a high (containing 56% sucrose) or a low-sucrose (containing 28% sucrose and 28% wheat flour) diet and inoculated with a strain ofStreptococcus mutans. Hyposalivation was induced by irradiation (35 Gy) and dental caries was significantly enhanced in irradiated rats fed a high-sucrose diet. However, the recovery of the strain ofS. mutans from rats fed high-sucrose was not significantly higher than that of rats fed a low-sucrose diet.

Adenomatoid odontogenic tumor

An 18-year-old Japanese male was referred to Osaka University Dental Hospital for examination of a slow-growing tumor of the left maxilla first noticed 3 years Before and left untreated. The swelling was approximate ly 3 cm in diameter and gave a parchment crackling to palpation. The overlying mucosa appeared normal in color and texture. The x-ray examination was performed by P-A skull radiograph, panoramic, occlusal and dental radiographs. Computed t opog raphy was also obtained. These radiographs demonstrated the typical radiographic features of an adenomatoid odontogenic tumor, i.e. a well-defined radiolucency with numerous

A unicystic ameloblastoma of the maxilla

A 33-year-old man complained of a swelling of the gingiva in the right maxi l lary molar region. This swelling has occurred as a painless swelling of the buccal gingiva in that region for a period of five years. The swelling had increased and decreased repeatedly from its onset, however it was left untreated. Two weeks ago, he noticed increase of the swelling and was treated with incision for drainage. His doctor said that a translucent-brownish liquid had been observed in the lesion at the time of incision. Oral examination revealed a bony hard swelling of the bucco-gingival sulcus in the region of the right upper second premolarmolar. The right maxi l lary tuberosity was