ABSTRACT
Abstract The effect of restoration depth on the curing time of a conventional and two bulk-fill composite resins by measuring microhardness and the respective radiosity of the bottom surface of the specimen was investigated. 1-, 3- and 5-mm thick washers were filled with Surefil SDR Flow-U (SDR), Tetric EvoCeram Bulk Fill-IVA (TEC) or Esthet-X HD-B1 (EHD), and cured with Bluephase® G2 for 40s. Additional 1-mm washers were filled with SDR, TEC or EHD, placed above the light sensor of MARC®, stacked with pre-cured 1-, 3- or 5-mm washer of respective material, and cured for 2.5~60s to mimic 2-, 4- and 6-mm thick composite curing. The sensor measured the radiosity (EB) at the bottom of specimen stacks. Vickers hardness (VH) was measured immediately at 5 locations with triplicate specimens. Nonlinear regression of VH vs EB by VH=α[1-exp(-EB/β)] with all thickness shows that the values of α, maximum hardness, are 21.6±1.0 kg/mm2 for SDR, 38.3±0.6 kg/mm2 for TEC and 45.3±2.6 kg/mm2 for EHD, and the values of β, rate parameter, are 0.40±0.06 J/cm2 for SDR, 0.77±0.04 J/cm2 for TEC and 0.58±0.09 J/cm2 for EHD. The radiosity of the bottom surface was calculated when the bottom surface of each material attained 80% of α of each material. The curing times for each material are in agreement with manufacturer recommendation for thickness. It is possible to estimate time needed to cure composite resin of known depth adequately by the radiosity and microhardness of the bottom surface.
Subject(s)
Composite Resins/radiation effects , Composite Resins/chemistry , Light-Curing of Dental Adhesives/methods , Curing Lights, Dental , Radiation Dosage , Reference Values , Surface Properties/radiation effects , Time Factors , Materials Testing , Linear Models , Analysis of Variance , Resin Cements/radiation effects , Resin Cements/chemistry , Polymethyl Methacrylate/radiation effects , Polymethyl Methacrylate/chemistry , Polymerization , Hardness TestsABSTRACT
A associação de técnicas de clareamento dental de dentes vitais e não vitais requer do profissional a individualização de um protocolo de trabalho para cada paciente. Este artigo mostra o relato de um caso clínico em que se utilizam diferentes técnicas de clareamento dental, aplicadas em dentes não vitais e vitais, com apoio na literatura existente. O protocolo de trabalho objetivou um tratamento com menor risco de reabsorção cervical externa e hipersensibilidade dentinária e com controle do nivelamento da cor obtida com o clareamento, entre os diferentes substratos dentais.
The combination of techniques for vital and non-vital tooth bleaching requires the establishment of a working protocol for each patient. This article shows a case report where different techniques of dental bleaching were used, both for non-vital and vital teeth, supported by the existing literature. The aim of this working protocol was to provide a treatment with minimal risk of external cervical resorption, dental hipersensitivity and control of the final shade in the different dental substrates.