Evaluation of the Combination of CO2 Laser and Bifunctional Bonding Agents for Composite Resin Repairs After 1 Year of Aging.

Objective: to evaluate the bond strength of repairs to composite resin restorations treated with CO2 laser and bifunctional monomers after 1 year of aging. Background: Adequate bond strength between a composite restoration and resin repair agent can be achieved through mechanical and/or chemical treatment. However, the longevity of such repairs is unknown. Methods: Resin blocks (volume: 125 mm3) were created. Failure surfaces were either not treated or were treated before the repair with a universal adhesive, a silane bonding agent and/or CO2 laser. The blocks were distributed into six groups (n = 6 per group): resin+resin group (RRG), universal adhesive+resin group (ARG), silane+universal adhesive group (SAG), laser+silane+universal adhesive group (LSAG), laser+universal adhesive group (LAG), and laser+silane group (LSG). After treatment, repairs were made with another resin composite. "Sticks" (1.0 mm2 in area and 1.0 cm in length) were cut from the specimens in each group and immersed in distilled water at 37°C. Microtensile bond strength was evaluated after 1 year of aging. Bond strength values were compared using the Kruskal-Wallis test and Dunn's test. Results: Bond strength was significantly higher in the LSAG compared with the RRG, adhesive system, LSG, whereas statistically similar results were found for the SAG, LSAG, and LAG. Bond strength was lowest in the RRG. The LSAG and LAG presented predominantly cohesive fractures. Conclusions: The bond strength of composite resin repairs was satisfactory over time. Treatment with CO2 laser contributed to the maintenance of bond strength during the 1-year storage period and bifunctional monomers present in the universal adhesive on the irradiated repair surface were of fundamental importance to the maintenance of bond strength values, as demonstrated by microtensile bond test and fracture pattern analysis.

INitial Steps of Insulin Action in Parotid Glands of Male Wistar Rats.

The parotid gland is the largest salivary gland. It produces watery saliva, rich in proteins (amylase, lysozymes, and antibodies). Due to the gland's morphological cytoarchitecture composed of only serous acini, it contributes almost 50% of total salivary volume upon stimulation. It has been reported that the prevalence of saliva secretion impairments, periodontitis, delayed wound healing, and xerostomia increase in diabetic patients. Herein we evaluated the acute effects of insulin on insulin receptor phosphorylation status and its substrates IRS-1 and IRS-2 in the parotid glands of adult male Wistar rats, using Western blot analyses. We confirmed an acute effect of insulin on IR/IRS/PI3K/Akt and MAPK intracellular pathway activation in the parotid glands of male Wistar rats similar to the classical metabolic targets of the hormone, like the liver.

In-Office Bleaching During Orthodontic Treatment.

OBJECTIVE: To demonstrate that it is possible to pursue teeth whitening treatment protocols during orthodontic treatment with no esthetic loss. CLINICAL CONSIDERATIONS: Many patients undergoing orthodontic treatment desire to have a straight and well aligned dentition, but also whiter teeth. For many years, it was believed that carrying out a whitening treatment with positioned orthodontic brackets in place would result in localized spots on the enamel labial surfaces of teeth. However, a deeper understanding of the bleaching process suggests that the oxidation caused by products, which results from hydrogen peroxide decomposition, are able to diffuse peripherally into the tooth structure and reach even that under the cemented brackets. Two in-office-bleaching treatments were performed in patients using orthodontic fixed braces in two or three 40-minute sessions using a 35% hydrogen peroxide. CONCLUSION: In-office bleaching is possible and effective, even with orthodontic brackets in position. The teeth were successfully bleached despite the presence of brackets. All biological criteria have been fulfilled satisfying patients' expectations of aligned and whitened teeth in less time than if treatments had been performed separately, with satisfactory results and no esthetic loss. CLINICAL SIGNIFICANCE: The whitening of teeth is possible during orthodontic treatment with fixed braces without any esthetic loss. The in-office bleaching treatment with brackets in position also may act as a motivation factor, preventing patient withdrawal or treatment interruption. Therefore, at the end of the orthodontic treatment, the patient is able to display an aligned, functional and whitened smile. (J Esthet Restor Dent 29:83-92, 2017).

Effect of whitening dentifrices on surface roughness of dental nanofiller-based composites. Stereomycroscopyand AFM analysis / Efeito de dentifrícios clareadores na rugosidade superficial de compósitos de nanoparticulados. Estereomicroscopia e AFM

Objective: the aim of this study was to assess the effects of whitening dentifrices on the surface roughness of three commercial nanofiller-based composite. Material and Methods: two optical analyses were performed: stereomicroscopy and atomic force microscopy (AFM). Disks (8.0 diam. x 2.0 mm thick.) of the nanocomposite Z350 (3M ESPE) and two nano-hybrid composites (EsthetXHD, Dentsply and Premisa, Kerr) were submitted to in vitro brushing (1000 cycles) with three whitening dentifrices (Colgate Luminous White, Oral-B 3D White e Close-Up Diamond Attraction) and a control (Colgate Total12). The results were analyzed by stereomicroscopy and rated according to the following criteria: 0 – no observed roughness, 1 – average roughness, 2 – great roughness. Data was submitted to Kruskall-Wallis non-parametric test followed by Tukey test (p = 0.05). Z350 specimens were assessed by AFM. Results: the surface roughness of composites brushed with whitening dentifrices was statistically higher than the roughness found in specimens brushed with conventional dentifrice. AFM analyses showed that, at a submicrometric scale, there was an increase in the number of peaks and irregularities in specimens brushed with whitening dentifrices. Conclusion: Whitening dentifrices may have an impact on the longevity of dental composites by an increase in its roughness. It is strongly recommended that clinicians guide their patients, warning them about the risks and consequences of their use.

Objetivo: o objetivo deste estudo foi avaliar os efeitos da abrasão produzida por dentifrícios clareadores sobre as superfícies de três marcas comerciais de resinas compostas contendo partículas nanométricas. Materiais e Métodos: A resina nanoparticulada Z350 (3M ESPE) e as resinas nano-híbridas EsthetXHD (Dentsply) e Premisa (Kerr) foram submetidas à escovação in vitro com três diferentes dentifrícios clareadores (Colgate Luminous White, Oral-B 3D White e Close-Up Diamond Attraction). Os espécimes de resina foram confeccionados com 8mm de diâmetro e 2mm de espessura. Foram produzidos 45 corpos de prova para os grupos experimentais e mais 15 espécimes para o grupo controle (dentifrício Colgate Total12). Após a realização de 1.000 ciclos de escovação, os espécimes foram armazenados em saliva artificial. A análise das superfícies escovadas foi obtida por estereomicroscópio. As rugosidades foram mensuradas segundo os critérios: 0 – sem rugosidade, 1 – média rugosidade e 2 – com muita rugosidade. Os dados obtidos foram analisados estatisticamente por teste não-paramétrico de Kruskall-Wallis seguido pelo teste de Tukey (p < 0,05). Os espécimes confeccionados com Z350 foram avaliados por microscopia de força atômica (AFM). Resultados: A rugosidade superficial dos espécimes de resina composta foi estatisticamente maior quando escovados com os dentifrícios clareadores em relação ao dentifrício controle convencional. Análise por AFM demonstrou, em uma escala submicrométrica, um aumento no número de picos na superfície dos espécimes da resina em que foi realizada a escovação com dentifrícios clareadores em comparação com o grupo controle. Conclusão: Os dentifrícios clareadores aumentaram a rugosidade superficial das resinas compostas podendo, assim, diminuir a sua longevidade.