給付方法の違いによる有床義歯患者の歯科に対する意識・行動の違いについて

In Japan, people are living longer and require dental services for more decades of their life than ever before. The disposable income for dental service has risen steadily, even though people have a reduced average income during their retirement years. Through education, financial stability, people have become increasingly concerned with their oral health. Elderly Japanese become more able and willing to invest much in oral health care. The purpose of this study was to compare dental health beliefs between wearers of insurance-provided removable dentures and wearers of other removable dentures. A total of 182 patients with removable dentures who attended the Prosthodontic Clinic of the Showa University Dental Hospital were interviewed followed by the oral examination. Patients with removable dentures had little concern for oral health. We found no significant differences in dental beliefs between wearers of insurance-provided dentures and wearers of other dentures. The results suggest a need for patient education by dentists, especially for patients who wear non-insurance-provided removable dentures

純チタンの鋳造性に関する研究(第4報)通気性の低い鋳型への鋳造

The purpose of this study was to evaluate the influence of casting molds with low permeability on the castability of pure titanium with an all directional pressured type casting machine. Two types of phosphate bonded casting molds were used, T-INVEST and T-INVEST C&B. We reported high performance of castability of pure titanium with an all directional pressured type casting machine, if the permeability of the investment was lower as possible. Specially prepared metal sealed rings to decrease gas permeability of casting mold were used. Two sizes of sprue condition were prepared, 1.26 and 1.48mm, under a casting pressure of 8kgf/cm^2. Five sizes of casting molds were prepared with mold diameters of 25, 35,45,55 and 65mm. The following results were obtained: A high percentage of castability was gained in T-INVEST using a high gas permeability casting mold with the sealed ring. A low percentage of castability was gained in T-INVEST C&B using a low gas permeability casting mold with the sealed ring. Back pressure action in the casting mold of T-INVEST C&B seemed to produce negative effects regarding the castability. These results indicated that the sealed ring was effective to promote pure titanium castability with a mold of high permeability

純チタンの鋳造性に関する研究(第3報)鋳造圧およびスプルー径がチタンの鋳込率に及ぼす影響について

We analyzed the external defects of castings with mesh grid patterns with 3 different kinds of phosphate bonded casting molds with 2 parameters (sprue diameter and casting pressure). Castability with pure titanium was affected by the parameters of sprue diameter, and casting pressure with different casting molds. The sprue condition was the most affective casting condition in the all directional pressure type casting machine. In 2 types of casting molds, one was strongly affected by the casting pressure in castability and the other was scarcely affected by the casting pressure. The former type of casting mold had a low permeability