[Evaluation of microtensile bond strength between resin composite and glass ceramic].

OBJECTIVE: To evaluate the microtensile bond strength of resin composite to glass ceramic, and the effect of surface treatment of resin composite and thermal cycling aging on the microtensile bond strength. METHODS: Rectangular blocks were made with dentin of extracted molars, resin composite or feldspathic glass ceramic respectively. The bonding surfaces of these rectangular blocks were sanded by 600-grit silicon carbide paper before luting. A self-etching resin cement was used as luting agent. The specimens were divided into groups according to the types of substrates of adhesion (dentin/glass ceramic or resin composite/glass ceramic), the way of surface treatments and whether thermal cycling aging ocurred. The dentin blocks were adhered to ceramic blocks as controls (group A1 and A2). The resin composite blocks were adhered to the ceramic blocks as experiment groups. The resin composite surfaces were treated by different ways before luting: no extra surface treatment (group B1 and B2), treated by ethyl methacrylate solution (group C1 and C2) or silane coupling agent (group D1 and D2), coarsened by 360-grit silicon carbide paper (group E1 and E2) or polished by 1 200-grit silicon carbide paper (group F1 and F2). After luting, the microtensile bond strength of the specimens were tested before (group A1-F1) or after (group A2-F2) thermal cycling aging. After microtensile bond strength test, the fracture bonding surfaces of the specimens were observed by a scanning electron microscopy to determine the type of bonding failure. The data were statistically analyzed using one-way analysis of variance. RESULTS: The microtensile bond strength of resin composite to glass ceramic with no extra treatment achieved high bond values before and after thermal cycling [B1 (30.02±3.85) MPa, B2 (26.83±3.14) MPa], which were statistically different from those of the control groups [A1 (20.55±4.51) MPa, A2 (12.94±0.69) MPa, P < 0.05]. The microtensile bond strength between the glass ceramic and resin composite did not increase after different surface treatments of resin composite. CONCLUSIONS: The microtensile bond strength between resin composite and glass ceramic achieved as similar bond strength as that between dentin and glass ceramic and even better. Surface treatment of resin composite via methyl methacrylate solution, silane coupling agent, coarsening, or polishing did not increase the microtensile bond strength effectually.

[Digital imaging fiber optic transillumination (DIFOTI) method for determining the depth of cavity].

OBJECTIVE: To analyze the accuracy of the digital imaging fiber optic transillumination (DIFOTI) on diagnosis of caries lesions depth using DIAGNOcam system. METHODS: This experiment adopted self-matching design. Seventy-four extracted teeth (molar: sixty-six, premolar: eight) with one caries lesions in proximity which were not damaged in surface marginal ridge were selected. Dental calculus and dental stains were removed from the extracted teeth for standby application. A sign was marked in the middle of the occlusal surface edge at the side of decay. Then the teeth were fixed in the standard model of dentition and cavities were adjacent with the sound tooth surface. Sticky wax was applied to seal the level of 2 mm beyond cemento-enamel junction (CEJ) in the direction of occlusion and interproximal space to imitate gingival margin and gingival papilla. The standard models of dentition was seated in imitation head mold. The lesions depth degree was looked into and checked with DIAGNOcam system. Besides, the pictures on the occlusal surfaces were recorded and saved. The sign above could be seen on the picture. The measuring tool in DIAGNOcam system was used to measure the depth of the caries from the sign (as starting point) to the deepest point of caries in the pictures and its length was recorded for a. The line a was lengthened to the contralateral edge of occlusal surface in the photo and the length was recorded for b. A line from the marked point on the occlusal surface edge of the extracted teeth was draw parallel to the line b on the corresponding photo and its length was recorded for c. The depth of the cavities on the projected images was recorded for d, and calculated d/a=c/b (digital optical fiber measured decay depth/caries damage depth of the image=actual tooth width/tooth width of the image), and d=c/b×a inferred. At last, the teeth were taken out from the standard model dentition. The decay of the tooth was removed completely. The actual depth of the cavity was recorded for D. The difference between d and D was recorded for Δd. The software of SPSS 20.0 was used to test the consistency of the results, and the MedCalc 14.8.1.0 software was used for Bland-Altman analysis. RESULTS: The intraclass correlation coefficient (ICC) between d and D was 0.951 (ICC>75%), P=0.263. There was a function relationship y=0.23+0.91x between d(x) and D(y). Bland-Altman analysis method showed that the mean of Δd (Δdmean) was 0.05 mm, the standard deviation of Δd (ΔdSD)=0.308, and the 95% confidence interval was (-0.55 to 0.65). The amplitude of difference was clinically acceptable. So the consistency of the two measurement modes was high. CONCLUSION: There was no significant difference between the depth of caries lesions checked with DIAGNOcam system and the depth of the actual cavity, and the consistency was very good. The vitro study suggests that the DIAGNOcam system may be used to assess the depth of caries cavity as a useful tool in diagnosis and treatment.

New commercial opportunities for advanced reproductive technologies in horses, wildlife, and companion animals.

As advanced reproductive technologies become more efficient and repeatable in livestock and laboratory species, new opportunities will evolve to apply these techniques to alternative and non-traditional species. This will result in new markets requiring unique business models that address issues of animal welfare and consumer acceptance on a much different level than the livestock sector. Advanced reproductive technologies and genetic engineering will be applied to each species in innovative ways to provide breeders more alternatives for the preservation and propagation of elite animals in each sector. The commercialization of advanced reproductive techniques in these niche markets should be considered a useful tool for conservation of genetic material from endangered or unique animals as well as production of biomedical models of human disease.