The Journal of Nihon University School of Dentistry最新文献

An attempt was made to quantify the location of various oral lesions using panoramic radiographs of benign tumors (20 ameloblastomas, 5 myxomas, 26 odontomas, 10 cementomas and 4 osteomas). The metrical data (integers) were obtained from a conversion table and the abscissa values (to the first decimal place) were obtained from the centroid of each of the tumors. Differential diagnosis among these lesions revealed that in the mandible, it is possible to differentiate between ameloblastomas and odontomas or osteomas. Thus, the present findings demonstrate that data on lesion location can be changed into metrical data for differential diagnosis of benign tumors.

A case of glomus tumor of the upper lip in a 57-year-old Japanese male is described. The patient had a tender swelling of the upper lip, and this was completely excised. The lesion was found to be encapsulated by fibrous connective tissue and composed of blood capillaries surrounded by sheets of epitheloid cells. Immunohistochemical examination revealed that the neoplastic cells were positive for S-100 protein, vimentin, desmin and actin. Although the endothelial cells of blood capillaries in the tumor tissue were positive for factor VIII, no reaction product was found in the tumor cells. These results suggested that the tumor cells had characteristics of smooth muscle cells.

The present study was undertaken to determine the effects of different dietary consistencies and malocclusion induced by extraction of molar teeth on the masticatory organs of weaning and adult rats, by determining the biochemical properties of masseter muscle, and also Ca and P levels in mandibular bone. Male SD rats, 3 and 20 weeks old, were divided into 3 groups. Group one (G-1) was maintained on a solid diet, and Groups two (G-2) and three (G-3) on a semi-solid diet. Furthermore, the mandibular molar teeth of G-3 rats were extracted. The experimental period was 120 days. The masseter muscle and mandibular bone weights of G-1 in weaning rats were increased significantly in comparison with G-3, but not in adult rats. The CPK activities in weaning and adult rats of G-1 were higher than those in the other two groups. The order of LDH activity in weaning and adult rats was G-3 > G-2 > G-1. G-2 and particularly G-3 showed significantly lower glycogen contents than G-1. The Ca and P contents of the mandibular bone in G-2 and G-3 were lower than those in G-1. These results suggest that a different dietary consistency and malocclusion induced by extraction of mandibular molar teeth have a considerable influence on the development of masticatory organs, mandibular bone and masseter muscle.

A case of Y-shaped lower bilateral central incisors found in an 18-year-old Japanese man is reported. Each of the central incisors had an abnormally high cusp located at the labial surface. The cause of this malformation of the lower central incisors is obscure, but we suspect that it was due to hyperplasia of the labial surface of the central lobe of the incisor during tooth development.

We carried out a detailed total body examination of a 62-year-old woman with osteoporosis who had bilateral defects in the mandibular processes. It was inferred that the defects in both articular heads were caused by resorption of small bone fragments following fracture. The quantity of bone salt was determined by microdensitometry, and a diagnosis of osteoporosis was then established. An improved bite was obtained by treatment consisting of tooth extraction and the preparation of partial dentures.

The ability of Actinomyces viscosus (A. viscosus) WVU 627 to attach to hydroxyapatite (HA) beads treated with either bovine fetuin or bovine mucin was studied. All preparations used were blocked with bovine serum albumin prior to incubation with [3H] thymidine-labeled A.viscosus cells. The quantity of fetuin or mucin adsorbed on the HA beads was determined by use of [3H] fetuin or [3H] mucin. Approximately 6 micrograms protein of [3H] fetuin and 20 micrograms of protein of [3H] mucin adsorbed to 5 mg of HA beads at saturation, respectively. The presence of fetuin or mucin on HA beads promoted attachment of the organism. However, HA beads treated with human whole saliva as a positive control promoted A.viscosus attachment more effectively than HA beads treated with these glycoproteins. Attachment of two additional strains (B 236 and B 25) of A. viscosus to HA beads was also promoted by these glycoproteins. The number of A.viscosus cells which attached to fetuin-treated HA beads was dose-dependent, except for strain B 25. For all three A.viscosus strains tested, attachment to the experimental pellicle with mucin was dose-dependent. These findings suggest that the use of these newly developed bacterial adhesion assay systems may be effective for elucidating bacterial adhesion mechanisms.

Linear measurements of passive mandibular border positions and angular measurements of passive opening were recorded in a group of patients with craniomandibular disorders. The relationships between signs and symptoms of craniomandibular disorders and abnormal capacity of movement were studied. There was significant association of some signs and symptoms related to the temporomandibular joint and abnormal vertical and horizontal excursions. On the other hand, there was only one relationship between occlusal factors and abnormal passive mandibular border positions.

Clinical cases of cysts of the jaw treated in the Department of Oral Surgery of our university during the 10 y between 1980 and 1989 were studied clinically. Patients with radicular cyst, dentigerous cyst, odontogenic keratocyst and postoperative maxillary cyst, which were found at relatively high frequencies, were further analyzed with regard to age, sex and anatomical distribution. A diagnosis of cyst was established in 1,444 patients during the above period, and 1,234 (85.5%) of them had cysts of the jaw. According to a pathological classification by Ishikawa's method, these patients included 509 (41.2%) with radicular cyst, 259 (27.0%) with dentigerous cyst, 95 (7.7%) with odontogenic keratocyst and 267 (21.6%) with postoperative maxillary cyst. The pattern of age distribution in cases of radicular cyst, odontogenic keratocyst and postoperative maxillary cyst was similar to that found in previous studies. Among patients with dentigerous cyst, those aged under 20 y accounted for about 60%. Radicular cyst occurred most frequently in the maxillary lateral incisors, dentigerous cyst in the mandibular wisdom teeth, and odontogenic keratocyst in the region between the mandibular molar and the ramus of the mandible.

Impression materials or prostheses can be contaminated with oral microflora and provide a significant source for cross-contamination. A study of such contamination was carried out using an approach different from that of infection control, which has often been investigated in previous studies. The study focused on microorganisms known to cause local and systemic diseases and which are normally found in the oral flora. The persistence of Streptococcus mutans (S. mutans), Escherichia coli (E. coli), Staphylococcus aureus and Candida albicans (C. albicans) on zinc-oxide eugenol, silicone rubber, irreversible hydrocolloid and polyether-rubber was investigated using 99mTc-labelled microorganisms. Ten specimens from each of the four impression materials were prepared as discs of 3 mm in height and 10 mm in diameter. After the specimens had been placed into a suspension of 99mTc-labelled microorganisms, remaining radioactivity was counted in a gamma counter. According to own findings, S. mutans was the most, and E. coli the least persistent on the specimen surfaces. The number of microorganisms removed after washing was less than the amount remaining on the surfaces. C. albicans was removed most easily from all impression surfaces that bore persistent microorganisms after washing. Other microorganisms showed various degrees of persistence according to the impression material.