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

Association between perceived chewing ability and oral health-related quality of life in partially dentate patients

<p>Abstract</p> <p>Background</p> <p>One of the most immediate and important functional consequences of many oral disorders is a reduction in chewing ability. The ability to chew is not only an important dimension of oral health, but is increasingly recognized as being associated with general health status. Whether perceived chewing ability and oral health-related quality of life (OHRQoL) are correlated to a similar degree in patient populations has been less investigated. The aim of this study was to examine whether perceived chewing ability was related to OHRQoL in partially dentate patients.</p> <p>Methods</p> <p>Consecutive partially dentate patients (N = 489) without signs or symptoms of acute oral disease at Tokyo Medical and Dental University's Prosthodontic Clinic participated in the study (mean age 63.0 ± 11.5, 71.2% female). A 20-item chewing function questionnaire (score range 0 to 20) was used to assess perceived chewing ability, with higher scores indicating better chewing ability. The 14-item Oral Health Impact Profile-Japanese version (OHIP-J14, score range 0 to 56) was used to measure OHRQoL, with higher scores indicating poorer OHRQoL. A Pearson correlation coefficient was calculated to assess the correlation between the two questionnaire summary scores. A linear regression analysis was used to describe how perceived chewing ability scores were related to OHRQoL scores.</p> <p>Results</p> <p>The mean chewing function score was 12.1 ± 4.8 units. The mean OHIP-J14 summary score was 13.0 ± 9.1 units. Perceived chewing ability and OHRQoL were significantly correlated (Pearson correlation coefficient: -0.46, 95% confidence interval [CI]: -0.52 to -0.38), indicating that higher chewing ability was correlated with lower OHIP-J14 summary scores (p < 0.001), which indicate better OHRQoL. A 1.0-unit increase in chewing function scores was related to a decrease of 0.87 OHIP-J14 units (95% CI: -1.0 to -0.72, p < 0.001). The correlation between perceived chewing ability and OHRQoL was not substantially influenced by age and number of teeth, but by gender, years of schooling, treatment demand and denture status.</p> <p>Conclusion</p> <p>Patients' perception of their chewing ability was substantially related to their OHRQoL.</p

6自由度顎運動測定装置の試用

The purpose of this study was to quantitatively analyze the mandibular movement by the Jaw tracking system with six degree of freedom (MM-JI-E). Displacements of the condyles under maximum clenching with successive loss of mandibular supporting zones were measured. The patient, a 29-year-old man, had been treated at an orthodontic clinic between 1994 and 1997, and temporary full coverage crowns were fabricated on four molars of the lower jaw. He showed no signs of abnormality of stomatognathic function. We measured the jaw movements with MM-JI-E, removing the crowns from the distal end of molars to the mesial. The condylar displacement values were displayed and calculated by the measurement of mandibular movement. When the supporting zones were reduced successively, both condyles moved upwards and slightly forwards (87-117°). The maximal condylar displacement values was 700μm without any support in the molars. We compared the measurements of MM-JI-E with those obtained with another jaw movement tracking system (Bio Pack), with three degree of freedom. The maximum opening paths in sagittal border movement were compared for the two measurement systems. The Bio Pack showed the deflection of the path of anterior maximum opening due to electronic error

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

チタン鋳造における鋳型温度の影響

The purpose of this study was to evaluate the titanium castability with a vacuum pressured type casting machine. We tested ethyl-silicate bonded investment "TITAVESTPS" of metal frame work. Four different mold temperatures (room temperature, 300℃, 600℃, and 900℃) were prepared for the present study, and casting was done in five times in each condition. When the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant (p<0.001) correlation on the castability. These results indicate that high performance of castability on the titanium was achieved when the mold temperature increased by using vacuum pressured type casting machine

Reliability and validity of the patient disability-oriented diagnostic nomenclature system for prosthetic dentistry

Purpose: The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This systemspecifies patient disability and the causative factor (i.e. ‘‘B (disability) caused by A (causative factor)’’). The purpose of this study was to examine the reliability and validity of this DNS. Study selection: The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names. Results: Krippendorff’s α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff’s α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff’s α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name. Conclusions: High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity

SELECTION OF RETAINERS IN LOWER OVERLAY DENTURE -In relation to the abutment tooth mobility­ (A laboratory study)

This study was done to evaluate the art of retaining the lower sub-complete, overlay denture, in relation to the abutment tooth mobility while the force was applied to the denture. The lower overlay denture was placed on a simulated model which was constructed of methyl-methacrylate and silicone rubber. The author developed and used the special devices for measuring the tooth mobility. Results obtained were as follows: 1. When a force is applied directly to the abutment, the tooth mobility, i.e. the lateral excursion of the tooth, is markedly reduced according to the favorable ratio of the clinical crown to the root length. Splinting by the bar is effective to reduce the lateral excursion. 2. When a force is applied to the denture indirectly to the abutment tooth, the lateral excursion changes greatly according to the retainer selected. 3. The clasp retainer shows the greatest change in the lateral excursion against every loading on the denture. 4. All three types of bar attachment show the least value of lateral excursion