Effectiveness of violet LED dental bleaching compared to 35% hydrogen peroxide: An in vitro study.

AIM: This in vitro study assessed the efficacy and adverse effects of violet LED bleaching with or without bleaching agents. MATERIAL AND METHODS: Dental blocks (n=40) were randomly distributed in 4 groups: violet LED (VL), 35% hydrogen peroxide (HP35), the association of hydrogen peroxide 35% with violet LED (VHP35) and the association of hydrogen peroxide 35% with blue LED (BHP35). Specimens were analyzed for Vickers microhardness initially, immediately after and seven days after ending bleaching protocol. The color analysis of the specimens was evaluated for bleaching effectiveness (ΔE2000, ΔE1976) and whiteness index (ΔWID) with EasyShade spectrophotometer, before bleaching protocol and seven days after ending bleaching protocol. The mineral composition of the enamel was evaluated by percentage of phosphorus and calcium on the enamel surface with energy dispersive spectroscopy (EDS). The color and the microhardness data were analyzed using one-way ANOVA with post-hoc Tukey (α=0.05). RESULTS: The microhardness test showed a difference among the groups only immediately after the completion of the protocol, in which there was a reduction in the value for the groups HP35 from 277,36 ± 21,56 to 198,76 ±32,2 (p<0,01); and BHP35 from 261,14 ± 36,01 to 212,66 ± 25,99 (p<0,01), but the microhardness was reestablished after seven days. Regarding EDS analysis, a reduction in the mineral percentage immediately after bleaching with the use of VL was observed, however, after seven days it was reestablished. Regarding the color analysis, there was no difference among the groups evaluated. CONCLUSIONS: The use of VL was effective as a dental bleaching tool and did not adversely affect the enamel surface after seven days of the ending of the bleaching protocol.

Effect of Different Adhesive Strategies on Bond Quality of Fiber Posts Cemented in Endodontically Treated Teeth.

Introduction: The purpose of this in vitro study was to assess the effects of anatomic root levels, different adhesive strategies and cementation system on bond strength (BS), nano leakage (NL) and degree of conversion (DC) after fiber posts cementation. Methods and Materials: Sixty-six roots of human premolars were endodontically prepared and divided according to the combination of adhesive application technique (manual passive, manual active and active vibratory) and the cementation system (Adper Single Bond 2/RelyX ARC [SBAR] and Single Bond Universal/RelyX Ultimate [SBUL]). Specimens were transversally sectioned into six 1-mm-thick serial slices, which were subjected to BS testing (n=7), to NL analysis using scanning electron microscopy (SEM) after slice immersion in silver nitrate (n=2), and micro-Raman spectroscopy for DC (n=2). Data were analyzed using two-way ANOVA and Bonferroni post-hoc test (α=5%). Results: Bond strength values significantly increased with active vibratory application technique (P<0.001), no significant difference was noted between adhesive systems. The cementation system Single Bond Universal/RelyX Ultimate demonstrated the lowest nano leakage values (P<0.05). The manual active and vibratory application techniques showed statistically higher degree of conversion values than the manual passive technique at the coronal and medium thirds (P<0.05); and the lowest results were observed with manual passive application to Single Bond Universal/RelyX Ultimate (P=0.016). Conclusion: The study concluded that techniques with active application (vibratory and manual) resulted in higher bond strength values. The mode of adhesive application influence the results.

Effect of Root Canal Sealers on Bond Strength of Fiber Posts to Root Dentin Cemented after one Week or six Months.

Eugenol-based root canal sealers (RCS) have been widely used by clinicians; however, their effect on resinous materials is still questionable. The objective of this study was to evaluate the influence of RCS at 1 week and 6 months' post obturation on the bond strength (BS) of glass fiber posts (GFP) to root dentin, using conventional and self-adhesive cementation systems (CS). The roots of 56 extracted human canines, were divided in eight groups (n=7) according to the combination of the following factors: RCS (with or without eugenol-Endofill and Sealer 26, respectively), storage period post obturation and prior GFP cementation (1 week and 6 months) and cementation systems (Variolink II - conventional resin cement or RelyX U200-self-adhesive resin cement). After one week, the specimens were transversely sectioned into six 1-mm-thick disks and were subjected to the push out BS test. The data were subjected to 3-way ANOVA and Tukey's tests (α=0.05). The BS were not affected by the RCS, neither the CS (P>0.05). Just the period post obturation showed statistically significant differences (P 0.05), where the GFP cemented 6 months after the endodontic treatment showed higher values than those cemented 1 week after it.

Color y características ópticas para restauraciones estéticas de dientes anteriores / Color and optical properties for esthetic restorations in anterior teeth

Las restauraciones estéticas de dientes fracturados del sector anterior con resinas compuestas consisten en un desafío estético, principalmente cuando se trata de un único incisivo central. El aumento en la demanda por parte de los pacientes de restauraciones estéticas con mínima intervención provocó un aumento en las restauraciones directas con resinas compuestas como solución a esa demanda. Sin embargo, la obtención de restauraciones biomiméticas con características ópticas, biológicas y mecánicas óptimas exige experiencia y conocimiento de materiales y de técnicas restauradores por parte de los clínicos. El objetivo de este trabajo es describir las propiedades del color y las características ópticas de los dientes anteriores para la realización de restauraciones estéticas junto con la presentación de un caso de fractura de un incisivo central superior restaurado con resina compuesta directa donde la forma, textura y color fueron fielmente reproducidos a partir de una secuencia detallada de estratificación y de técnicas de acabado/pulido

Esthetic restorations of dental fractures in the anterior segment with composite resins remain in a complex aesthetic challenge, mainly when it is about a single central incisor. Increased patient demand for aesthetic dentistry with minimal invasive procedures has resulted in the extensive use of direct composite resin restorations to overcome this challenge. However, the achievement of biomimetics restorations with optimal optical, biological and mechanical characteristics demands on clinicians experience and knowledge of materials and restorative techniques. The aim of this article is to describe color and optical properties of anterior teeth for esthetics restorations presenting a case of direct composite resin restoration of a single central incisor fractured where the shape, texture and color were faithfully reproduced following a step-by-step sequence of layering and finishing/polishing techniques