Kazutoshi Kakimoto

Fabrication of all-ceramic crowns by a new method.

A new method of all-ceramic production using alumina coping has been developed. The present study investigates the influence of secondary firing (glass infiltration firing) conditions. Samples of porcelain build-up without secondary firing were also assessed. The suitability of coping that included secondary firing was found to be affected by the rate of temperature increase during the secondary firing. However, cracking developed in the fired porcelain if porcelain was built up onto secondarily-fired coping. In contrast, cracking did not occur with coping that was not secondarily fired. The bending strength after porcelain build-up was 70 MPa or higher, suggesting the possibility of clinical applications as an anterior crown. These findings establish that this is method of producing all-ceramic crowns that allows for low-cost manufacture in a short period of about 1 h.

Development of Clinical Examination Device for Complete Denture Construction.

A clinical examination device for complete denture construction was developed, and its use was investigated. The device was found to be effective for recording and examining the relation between artificial teeth and the alveolar ridge. Additionally, it was confirmed to be possible to make the occlusal rim and to arrange artificial teeth in accordance with the location of the incisive papilla and alveolar ridge. This device also allows fabrication of the base of the model parallel to the occlusal plane.

Horizontal dimensional changes in maxillary dentures made of polyethersulfone.

The purpose of this research was to investigate the horizontal dimensional variations in maxillary complete dentures fabricated with Polyethersulfone (PES) using compression molding. Dimensional changes were compared for the three different materials PES, Polysulfone (PSF), and PMMA.The results were as follows:1. In the case of the occlusion rim, all three materials displayed horizontal shrinkage both in the anteroposterior and in the left/right directions. PMMA had the largest shrinkage, followed by PSF and PES in that order.2. In the case of the denture, PSF had the largest horizontal shrinkage in the anteroposterior direction, followed by PES and PMMA in that order. In the left/right direction the shrinkage was largest for PMMA, followed by PES and PSF in that order.3. PES, like PMMA displayed a uniform shrinkage in the anteroposterior direction, with little difference observed between shrinkage in the anterior and posterior region. However, PES, like PSF, had greater shrinkage in molar region than the anterior region.