Since color matching is considered a subjective procedure, accurate shade choice is often the most challenging stage of recreating the natural appearance of teeth. Furthermore, accurate determination of tooth color is imperative for the final outcome of dental restorations. The purpose of this research is to assess the accuracy of color match between diverse shade selection methods throughout a systematic review and meta-analysis. Two independent investigators (L.H. and R.B.) screened the literature in five electronic databases. Randomized controlled trials or in vitro papers studying the effect of using either digital shade selection or visual shade selection on the accuracy of color match were included. A total of 13 manuscripts comprised the meta-analysis. Color difference (ΔE) between restorations where the shade matching was performed by the conventional method was greater than those where the shade matching was performed by computerized methods (p = 0.007). According to the subgroup analysis, only the use of digital photographs for shade matching showed a reduction in the (ΔE) (p < 0.0001), while the use of a spectrophotometer has no advantages over the use of visual shade guide tabs (p = 0.57). On the other hand, global analysis showed that incorrect shade matching was higher when the conventional method using shade guide tabs was used (p < 0.001), irrespective of whether a spectrophotometer or a digital camera was used (p < 0.001). This study concluded that the use of digital photography and spectrophotometric measurements led to fewer color differences and less incorrect shade matching than conventional methods using color shade tabs.

La investigación es un procedimiento reflexivo, sistemático, controlado y crítico que tiene por finalidad descubrir o interpretar los hechos de un fenómeno. El diseño de investigación constituye el plan general del investigador para obtener respuestas a sus interrogantes o comprobar la hipótesis de investigación, además, estipula la estructura fundamental y especifica de la intervención.

No abstract

The microhardness is an essential property of tooth enamel; there may be many factors that alter or diminish this quality causing weakness, one of which is dental fluorosis. The aim of this study was evaluate the surface microhardness of fluorotic enamel compared with healthy enamel. Two hundred forty extracted human molars were classified into four groups: Healthy (H), mild (MI), moderate (MO) and severe (S) fluorosis according to the Dean index. All samples were analyzed by Micro Vickers Hardness Tester. Average, standard deviation and ranges were calculated for quantitative variables, the ANOVA and Tukey test was used to identify differences between groups. The mean values of surface microhardness in HVN were: H, 333.4; MI, 290.3; MO, 266.1; S, 252.0. The differences between mean surface microhardness among healthy group and fluorotic groups were statistically significant (p

The objective of this work was to evaluate the effect of pretreatment with commercial sodium hypochlorite, 5.25%, with a self-etch adhesive (Optibond Versa) in its original formula and with the incorporation of silver nanoparticles (NaAg) on fluorotic dentin. 240 human molars were classified according to fluorosis severity with Thylstrup-Fejerskov Index (TFI) and subdivided into three study subgroups according to the adhesive technique: (1) self-etch (SE) control subgroup; (2) NaOCl/SE subgroup; (3) NaOCl/SE + NaAg subgroup. The nanostructural characteristics were observed by AFM, TBS was tested, and hybrid layer formation was observed by SEM. One-way analyses of variance (ANOVA) and Tukey-Kramer post hoc tests were used. No statistically significant differences were found in roughness values in any of the subgroups and subgroups studied. Remnants of smear layer were detected in areas devoid of resin tags in SEM images of samples bonded with subgroup 2, in contrast to subgroup 3. No statistically significant difference between any of the results was found in TBS and a greater number of adhesive failures were observed. The results show that the pretreatment technique of 5.25% NaOCl and the incorporation of NaAg to the self-adhesive system do not produce a surface more adequate for a better adhesion.