ABSTRACT
Self-adhesive, dual-polymerizing resin cements require no treatment to the prepared tooth surfaces before cementation. Aim: The aim of this study was to evaluate the influence of curing mode on bond strength (BS) of three cementing systems to bovine dentin. Methods: The buccal enamel surfaces of 50 bovine incisors were removed to expose dentin and to flat the surface. The teeth were divided into five groups (n=10), which consisted of two resin cements (Multilink and Clearfil SA Cement) that were tested in dual- (halogen light for 40 s) and self-cured modes, and a control (RelyX ARC). Two cylinders of resin cements (1.0 mm X 0.75 mm) were prepared on each bonded dentin surface. After 24h at 37oC, resin cylinders were subjected to micro-shear testing in a universal testing machine (4411/Instron - 0.5 mm/min). Data were statistically analyzed by two-way ANOVA, Tukey and Dunnett`s test (5%). Results: Multilink showed higher BS than those observed on Clearfil SA. Light-curing resulted in higher BS for both Multilink and Clearfil SA. When Multilink was light-cured, no significant difference on BS was demonstrated between it and RelyX ARC. Conclusions: The highest BS values were obtained in control group and light-cured Multilink resin cement (AU)
Subject(s)
Animals , Cattle , Adhesives , Dentin , Resin Cements , Tensile StrengthABSTRACT
Adequate polymerization plays an important role on the longevity of the composite resin restorations. OBJECTIVES: The aim of this study was to evaluate the effect of light-curing units, curing mode techniques and storage media on sorption, solubility and biaxial flexural strength (BFS) of a composite resin. MATERIAL AND METHODS: Two hundred and forty specimens were made of one composite resin (Esthet-X) in a stainless steel mold (2 mm x 8 mm Ø), and divided into 24 groups (n=10) established according to the 4 study factors: light-curing units: quartz tungsten halogen (QTH) lamp and light-emitting diodes (LED); energy densities: 16 J/cm² and 20 J/cm²; curing modes: conventional (CM) and pulse-delay (PD); and permeants: deionized water and 75% ethanol for 28 days. Sorption and solubility tests were performed according to ISO 4049:2000 specifications. All specimens were then tested for BFS according to ASTM F394-78 specification. Data were analyzed by three-way ANOVA followed by Tukey, Kruskal-Wallis and Mann-Whitney tests (α=0.05). RESULTS: In general, no significant differences were found regarding sorption, solubility or BFS means for the light-curing units and curing modes (p>0.05). Only LED unit using 16 J/cm² and PD using 10 s produced higher sorption and solubility values than QTH. Otherwise, using CM (16 J/cm²), LED produced lower values of BFS than QTH (p<0.05). 75% ethanol permeant produced higher values of sorption and solubility and lower values of BFS than water (p<0.05). CONCLUSION: Ethanol storage media produced more damage on composite resin than water. In general the LED and QTH curing units using 16 and 20 J/cm² by CM and PD curing modes produced no influence on the sorption, solubility or BFS of the tested resin.
Subject(s)
Humans , Curing Lights, Dental , Composite Resins/radiation effects , Light-Curing of Dental Adhesives/methods , Absorption , Analysis of Variance , Composite Resins/chemistry , Ethanol/chemistry , Materials Testing , Polymerization/radiation effects , Solubility , Statistics, Nonparametric , Tensile Strength , Time Factors , Water/chemistryABSTRACT
O ozônio é uma variedade alotrópica do oxigênio constituída por uma molécula triatômica desse elemento. Tem sido considerado um potente oxidante que pode ser usado na Odontologia. O seu uso apresenta-se como nova alternativa no tratamento de lesões de cárie, uma vez que sua eficácia clínica tem sido comprovada por diversos estudos relacionados à inativação de vírus, bactérias e fungos. Em função de apresentar propriedade comprovada na inibição e/ou destruição de muitas bactérias da cavidade bucal - tais como Streptococcus mutans, Streptococcus sanguis e Actinomyces odontolyticus -, o seu uso no tratamento das lesões cariosas é baseado em sua atividade antimicrobiana, com diminuição da acidez do biofilme, possibilitando a difusão de íons cálcio e fosfato nas lesões cariosas e permitindo a remineralização da dentina e esmalte afetados. Atualmente, a ozonioterapia é considerada uma alternativa promissora pelo seu baixo custo de investimento e manutenção, facilidade de aplicação e resultados clínicos satisfatórios. Porém o ozônio decompõe-se rapidamente e a presença de radicais de oxigênio pode interferir na polimerização de materiais adesivos. Dessa forma, o objetivo deste trabalho é apresentar uma revisão de literatura sobre a utilização do ozônio no tratamento de lesões cariosas e seu efeito sobre procedimentos restauradores adesivos.