The Bulletin of the Kanagawa Dental College : BKDC最新文献

The recording accuracy of Sirognathograph (Siemens, West Germany) was conducted by means of an experimental apparatus. Diagrams of mandibular border movements in three dimensional directions were performed. The results showed the distortion was not recognized within 5 mm of primary condition in a subject, but slightly between 5 mm and 10 mm. In a distance of more than 15 mm, a considerable distortion was increased until at the maximum opening position.

The periodontium, especially the periodontal ligament and alveolar bone, are tissues constantly subjected to physical stress such as occlusion and mastication. This study was designed to explore the effect of the pulsed electromagnetic fields (PEMF) on the cell attachment and the spread of human periodontal ligament fibroblasts (HPLF) and rat osteoblasts (ROB). PEMF are categorized as one type of mechanical stress. HPLF were obtained by the explantation method described by Saito et al. They were then subcultured in Dulbecco's modified Eagle's medium (D-MEM) and supplemented with 2 mg/ml dialyzed fetal calf serum protein (FCSP), 50 micrograms/ml ascorbic acid and penicillin/streptomycin after trypsinization. ROB were isolated from a two-day-old rat calvaria by the sequential bacterial collagenase digestion method described by Dziak and Brand and were subcultured in D-MEM supplemented with FCSP, ascorbic acid and penicillin/streptomycin. After the confluent HPLF were cultured with serum-free MCDB 107 medium, the quiescent HPLF were exposed with or without PEMF for 24 hr. This was followed by the collection of the control conditioned medium (C-CM) and PEMF exposed conditioned medium (PEMF-CM). The cell attachment assay was performed so that the hydrophobic 24 multiwells were coated with the whole conditioned medium or fractionated conditioned medium by a PO-60K column. After coating, heat inactivated BSA blocked nonspecific sites for cell adhesion, and 3H-TdR labeled HPLF or ROB were cultured on the precoated wells. The activity of cell attachment and spreading was determined by the radioactivity of 3H-TdR using a scintillation counter. The characters of cell attachment factors derived from HPLF were hydrophobic, heat labile and proteolytic enzyme digestible. In addition, the fractionated PEMF-CM enhanced the spreading activity of ROB. PEMF induced the 10 KDa which can enhance the HPLF and ROB spreading. Therefore, the cell attachment and spreading factors secreted by HPLF exposed with PEMF may regulate HPLF and also ROB.

The mannequin exercises which are practiced in clinical exercises of dental colleges are getting more important these days. It is necessary to compare the difference between the efficiency of a mannequin and a living body. When making a partial denture using the simulation model, it is very important to know what kind of impression materials you are able to use or the accuracy of those impression materials. A study on a simulation model is used for making a partial denture. Choosing some sort of impression materials and treatment positions have the possibility to exert influence on impression taking through the process from impression taking to model making. At first, to find the impression materials which are able to take the impression of simulation model's simulate mucous membrane, choose nine impression materials and examined them. Then, examine the effective relationship between the impression taking and the mannequin's head and back position. Establish a mannequin's head and back inclination from four positions. Cut the acquired four models at the same location and examine them. The following results were obtained. 1. Of the impression materials used, with the exception of Flexicon and Rapid, there was no adhesiveness observed with the artificial mucosa. In addition, in the case of Exaflex Injection, Regular and Putty, there were noninduration sections among the sections that contacted with the artificial mucosa. 2. Regarding the effect of the bodily position, changes in the impression were observed for the upper jaw in the case of the median sagittal section C and the lateral section S. This was particularly frequent on the palate in the molar region.(ABSTRACT TRUNCATED AT 250 WORDS)