Randomized clinical trial of 2 nonvital tooth bleaching techniques: A 1-year follow-up.

STATEMENT OF PROBLEM: Controlled clinical trials comparing the effectiveness of the walking bleaching (WB) technique and the inside-outside (I-O) technique used in a short daily regimen are lacking. PURPOSE: The purpose of this randomized clinical trial was to investigate the effectiveness of WB with that of the I-O technique conducted over 4 weeks and to compare color changes after 1 year. MATERIAL AND METHODS: Discolored and endodontically treated anterior teeth received a cervical seal and were randomly divided into groups according to the technique. In the WB group (n=9), a mixture of sodium perborate and 20% hydrogen peroxide was applied in the pulp chambers and replaced weekly up to 4 weeks. For the I-O group (n=8), participants applied 10% carbamide peroxide in the pulp chambers and wore custom-fitted trays for 1 hour per day over 4 weeks. CIELab parameters were obtained using a spectrophotometer at baseline, during bleaching (1, 2, 3, and 4 weeks) and after 1 year. Changes in color (ΔE), lightness (ΔL*), green-red axis (Δa*), blue-yellow axis (Δb*), and absolute color parameters (L*, b*, and a*) for each evaluation time were calculated and analyzed by repeated measures analysis of variance (ANOVA) and post hoc Bonferroni test (α=.05). RESULTS: No significant differences between WB and I-O techniques were observed for ΔE, ΔL*, Δa*, Δb*, L*, a*, or b* values (P>.05); however, significant differences were observed among the evaluation times (P<.05). Color changes observed after 2 weeks were stable after 1 year; ΔL* and Δa* values after 1 year were not significantly different from the 1-week evaluation, and significant changes in Δb* after 3 weeks were maintained at the 1-year follow-up. The same trend was observed for the absolute CIELab color parameters. CONCLUSIONS: Both WB and I-O regimens were similarly effective as shown by significant ΔE after 2 weeks and no color regression after 1 year.

Strength and wear resistance of a dental glass-ionomer cement with a novel nanofilled resin coating.

PURPOSE: To evaluate the influence of different resin coating protocols on the fracture strength and wear resistance of a commercial glass-ionomer cement (GIC). METHODS: A new restorative concept [Equia (GC Europe)] has been introduced as a system application consisting of a condensable GIC (Fuji IX GP Extra) and a novel nanofilled resin coating material (G-Coat Plus). Four-point fracture strength (FS, 2 x 2 x 25 mm, 14-day storage, distilled water, 37 degrees C) were produced and measured from three experimental protocols: no coating GIC (Group 1), GIC coating before water contamination (Group 2), GIC coating after water contamination (Group 3). The strength data were analyzed using Weibull statistics. Three-body wear resistance (Group 1 vs. Group 2) was measured after each 10,000 wear cycles up to a total of 200,000 cycles using the ACTA method. GIC microstructure and interfaces between GIC and coating materials were investigated under SEM and CLSM. RESULTS: The highest FS of 26.1 MPa and the most homogenous behavior (m = 7.7) has been observed in Group 2. The coated and uncoated GIC showed similar wear resistance until 90,000 cycles. After 200,000 wear cycles, the coated version showed significantly higher wear rate (ANOVA, P< 0.05). The coating protocol has been shown to determine the GIC fracture strength. Coating after water contamination and air drying is leading to surface crack formation thus significantly reducing the FS. The resin coating showed a proper sealing of GIC surface porosities and cracks. In terms of wear, the coating did not improve the wear resistance of the underlying cement as similar or higher wear rates have been measured for Group 1 versus Group 2.

Lesões cervicais não cariosas (LCNCs): parte II: sugestões para a clínica diária / Non carious cervical lesions (NCCLs): part II: suggestions for the daily practice

As LCNCs apresentam etiologia multifatorial e expressão crescente na clínica diária. Seu estudo é cada vez mais necessário, para possibilitar correto diagnóstico, tratamento e prevenção. A resina composta apresenta–se como melhor material para restaurar as LCNCs com estética e funcionalidade. Outra grande vantagem dela é o selamento da dentina cervical exposta, que elimina a sensibilidade e traz, assim, conforto ao paciente. Todavia, a adoção de um protocolo criterioso, especialmente nas etapas do isolamento do campo operatório, aplicação do sistema adesivo, inserção da resina composta, acabamento e polimento, é essencial para o sucesso restaurador. Sendo assim, a parte II desta série apresenta dois protocolos clínicos como sugestões para se obterem resultados mais previsíveis, com base em uma interpretação conservadora da literatura.

NCCLs presente multifactorial etiology and increased prevalence in the daily practice. Its study is increasingly necessary to enable correct diagnosis, treatment and prevention. Composite resin has shown to be material of choice to restore NCCLs with esthetics and function. Another great advantage is sealing of exposed cervical dentin, eliminating tooth sensitivity, thus bringing comfort to the patient. However, the adoption of a careful protocol, especially in the steps of isolation of the operative field, application of adhesive system, insertion of composite resin, finishing and polishing, is essential for successful restorations. Therefore, the second part of this three-part series presents two suggestions of clinical protocols to obtain more predictable results, based on a conservative approach of the literature.