This study evaluated the effects of four adhesive metal primers on the shear bond strength of a heat curing denture base resin(Lucitone 199) to cobalt-chromium alloy(Biosil-f). The adhesive metal primers were Cesead Opaque Primer, Metal Primer, MR Bond, and Super-Bond liquid. The metal surface primed or nonprimed was filled with the heat-curing methyl methacrylate resin. The specimens were stored in water at 37 degrees C for 24 hours and the alternately immersed in water bath at 5 C and 55 C for up to 2,000 thermal cycles. Shear bond strengths were measured using UTM at a crosshead speed of 0.5mm/min. Failure surface were examined under magnifying glasses. All the primers examined improved the shear bond strength between denture base resin and cobalt chromium alloy compared with nonprimed specimens before thermal cycling. The bond strength of Cesead Opaque Primer was greatest. And after 2,000 thermal cycles, the bond strengths between resin and cobalt-chromium alloy were decreased but the difference between thermal cycling 0 and 2,000 at Cesead Opaque primer and Metal Primer were not significant. This study indicated that Cesead Opaque Primer & Metal Primer is effective primers to obtain higher bond strength between heat cured denture base resin and cobalt-chromium alloy.
Adhesives* ; Alloys* ; Baths ; Chromium ; Cobalt ; Denture Bases* ; Dentures* ; Eyeglasses ; Glass ; Hot Temperature ; Water

The purpose of this study was to develop a semi-quantitative food frequency questionnaire (SQ-FFQ) for subjects aged 50yr and over and to evaluate the validity of this SQ-FFQ. Dietary intake was assessed using SQ-FFQ that included 98 commonly consumed flood items selected from the results of the Korean Health and Nutritional Survey, 1998. Subjects (n = 2,660) aged 50yr and over were recruited from 7 metropolitan cities and 8 small cities. Each subject was interviewed using this SQ-FFQ developed in our laboratory and 24hr-recall method. Excluding incomplete data, Data from 1,149 subjects were used in this validity study. The nutrient intakes assessed by this SQ-FFQ were validated by comparing with the results from 1 day 24-hour recalls. Pearson's correlation coefficients between two methods were 0.71, 0.64, 0.53, and 0.43 for energy, carbohydrate, protein, and fat, respectively for all subjects. Spearman's correlation coefficients were higher than those of Pearson's correlation coefficients. Kappa values for energy, carbohydrate, protein, and fat were 0.79, 0.72, 0.70, and 0.64, respectively. The percentage for misclassification of the lowest quartile into the highest quartile or vice versa was 1.25-1.39% for all nutrients. Therefore, this SQ-FFQ seems to be useful in assessing the nutritional status of the middle-aged and elderly subjects in Korea.
Aged* ; Humans ; Korea ; Nutrition Surveys ; Nutritional Status* ; Surveys and Questionnaires