[Evaluation of dental medical quality based on efficacy coefficient model].

PURPOSE: To evaluate the dental quality comprehensively by data model of efficacy coefficient based on the principle of multi-objective programming. METHODS: The correlation index of dental medical quality was selected by Delphi method, while the index weight was determined by the scale of the analytic hierarchy process. Then efficacy coefficient method was used to evaluate the dental quality of Shanghai Stomatological Hospital in a certain period. RESULTS: During the period of 2016-2017, the D value of the efficiency coefficient was 84.92, 83.41, 86.99 and 81.98, respectively, which demonstrated that the overall quality of the hospital was in good condition. CONCLUSIONS: The efficiency coefficient method can objectively reflect the comprehensive level of medical quality, which can provide a strong support for comprehensive evaluation and control of the quality of dental hospital.

[Influences of filler content and size on the translucency parameter of resin composites].

PURPOSE: The objective of this study was to investigate the influences of filler content and size on the translucency parameter of non-layered resin composites. METHODS: Three types of fillers (0.7 µm, 1.0 µm and 1.5 µm) were mixed at weight contents of 60wt%, 70wt%, 75wt%, and 80wt%. The L*, a* and b* value was analyzed based on CIELab color space of the specimen respectively on black and white background. The results of each test were analyzed with one-way ANOVA followed by Tukey's HSD test using SPSS 20.0 software package. RESULTS: For each filler size, there was a trend of decreasing translucency parameter as the filler content increased (P<0.05). The filler size did not affect the translucency parameter of the composites in this study. CONCLUSIONS: When the fillers content changed from 60wt% to 80wt%, there is a trend of decreasing translucency parameter as the filler content increased, and the filler size may not influence the translucency parameter of the composites when the size changed from 0.7 µm to 1.5 µm.

[Color distribution of the anterior teeth in 137 elder people].

PURPOSE: To study the color distribution of the anterior teeth in elder people. METHODS: 612 anterior teeth from 137 people aging from 60 to 81 years and 200 anterior teeth from 100 young people aging from 20 to 40 years were collected. A digital colorimeter was used to measure the value of L*,a*,b* of the teeth, and the chromatism (deltaE) was calculated according to the formula deltaE=(deltaL*(2)+deltaa*(2)+deltab*(2))1/2. All data were analyzed with SAS 6.12 software package for Student's t test. RESULTS: Totally, there were 612 vital anterior teeth from elder people, including 201 central incisors,199 lateral incisors and 212 canines, were collected. No difference was found between the teeth on the right side and the left side in terms of L*,a*,b*value(P>0.05). The mean value of L*,a*,b* of the central incisors was 71.2+/-6.22,0.97+/-1.12,15.9+/-5.04, respectively and that of the lateral incisors and the canines were 69.6+/-5.52,0.6+/-1.18,13.9+/-4.15 and 68.4+/-5.99,0.15+/-1.02,19.6+/-4.87, respectively.The mean value of L*,a*,b* of the central incisors and the canines from the youngster was 75.82,-0.11,12.68 and 72.07,1.22,17.92, respectively.There were significant differences between the central incisors and the lateral incisors as well as the canines (P<0.05) in terms of L* value. Meanwhile difference was also found among the incisors and the canines in terms of a* and b* value(P<0.05). The deltaE between the central incisors and the lateral incisors was 2.945NBS, and the value between the canines and the central incisors as well as the lateral incisors was 4.629NBS and 5.832NBS, respectively, indicating that the color difference could be perceived visually. Compared to the youngster, the teeth of the elder people demonstrated a lower L* and a* value, but a higher b* value (P<0.05). CONCLUSIONS: Among elder people, the central incisors look much brighter than the lateral incisors and canines, while the canines have more redness and yellowness than the incisors, and the color of the lateral incisors exhibits lighter than the central incisors and the canines. Compared to the teeth from younger people, the teeth from elder people look much darker and yellower but less red. Supported by Shanghai Leading Academic Discipline Project (Grant No.T0202).

[Clinical analysis of colour distribution in tetracycline teeth].

PURPOSE: To analyze the colour range and distribution of tetracycline teeth, and the difference from normal teeth. METHODS: 142 cases with 468 anterior tetracycline teeth and 100 cases with 200 normal anterior teeth were collected. The color was measured by a computer-aided Shade-Eye NCC colorimeter, and expressed in terms of 3 coordinate values (L,a,b) of the CIE-1976-Lab color system. Chroma (Cab)and hue (h(ab) degrees)were calculated according to the value of a and b. The data were analyzed with SAS6.12 software package for description, Student's t test and Duncan test. RESULTS: The range of L, a, b Cab, h(ab) degrees of tetracycline teeth was 42.33-77.00, -0.6-9.6, 2.67-31.5, 5.24-31.89, 38.62 degrees-95.47 degrees, respectively. Significant difference of L value and hue (h(ab) degrees) was found between tetracycline teeth and normal teeth (P < 0.01), which indicated that tetracycline teeth were darker and redder than normal teeth. There was no difference of chroma (Cab) between tetracycline teeth and normal teeth (P > 0.05). Moreover there was significant difference of L value between canine and central incisor, and of H value (h(ab) degrees) between canine and lateral incisor in tetracycline teeth, which indicated that canine was darker and redder than incisor, and redder than lateral incisor, but there was no significant difference in chroma (Cab) among all anterior teeth and no difference in L, a, b between central incisor and lateral incisor. CONCLUSIONS: The study showed the color distribution of tetracycline teeth was wider and more dispersive than normal teeth, and much darker and redder than normal teeth. Supported by Shanghai Leading Academic Discipline