ABSTRACT
O objetivo deste trabalho foi avaliar a capacidade seladora de um material restaurador provisório, Villevie, e de uma resina composta, Tetric Ceram, associada a dois tipos de sistema adesivos, XENO III e Single Bond. Quarenta incisivos inferiores unirradiculares foram distribuídos em três grupos de dez dentes cada e cinco dentes para cada grupo controle, positivo e negativo. Os espécimes, após a cirurgia de acesso, foram preparados por meio de sistema de instrumentação rotatória e irrigados com água destilada e deionizada. A porção externa dos dentes foi impermeabilizada até 2 mm aquém da margem externa da cirurgia de acesso. Colocou-se no interior do canal radicular um cone de papel seguido de uma pensa de algodão impregnados com solução alcoólica de dimetilglioxima 1%. A cavidade endodôntica foi selada de acordo com os seguintes grupos: GA- sistema adesivo autocondicionante XENO III + resina composta; GB- sistema adesivo Single Bond + resina composta; e GC- selador provisório. Os espécimes foram imersos em recipientes contendo solução de sulfato de níquel 5% e submetidos à ciclagem térmica por 72h. Os testes de Kruskal-Wallis e Dunn foram utilizados para análise dos resultados com nível de 5% de signifcância. O menor nível de microinfltração foi observado no grupo do restaurador provisório (GC), com diferença estatística signifcante em relação aos demais grupos (P<0,001). Os grupos A e B mostraram-se semelhantes ao controle positivo (P>0,05), com os maiores índices de microinfltração. Concluiu-se que nenhum dos materiais avaliados foi capaz de impedir a microinfltração coronária.
The purpose of this study was to evaluate the sealing capacity of a temporary restorative material (Villevie) and a composite resin, Tetric Ceram, associated with two adhesive systems (XENO III and Single Bond). Forty single-rooted mandibular incisors were distributed into three experimental groups of 10 teeth each, and two control groups (positive and negative) of 5 teeth each. After preparation of the access cavities, the canals were instrumented with a rotary system and irrigated with distilled deionized water. The external surfaces of the teeth were rendered water-proof up to 2 mm from the external margins of the access cavities. A paper point and a coton mesh impregnated with an alcoholic 1% dimethylglyoxime were placed inside the root canals, and the endodontic access cavities were sealed according to the following groups: GA- XENO III self-etch adhesive system + composite resin; GB- Single Bond etch-and-rinse adhesive system + composite resin; and GC- temporary restorative material. The specimens were immersed in receptacles containing a 5% nickel sulfate solution and subjected to a thermal cycling regimen during 72 h. The Kruskal-Wallis and Dunn's tests were used for statistical analysis of the results at 5% signifcance level. The group restored with the temporary restorative material (GC) presented statistically signifcant less coronal leakage than the other groups (p<0.001). GA and GB were statistically similar to the positive control (p>0.05), showing the highest levels of coronal leakage. None of the tested materials was able to prevent the occurrence of coronal leakage.
ABSTRACT
Dentin adhesion procedure presents limitations, especially regarding to lifetime stability of formed hybrid layer. Alternative procedures have been studied in order to improve adhesion to dentin. OBJECTIVE: The aim of this study was to evaluate in vitro the influence of deproteinization or dentin tubular occlusion, as well as the combination of both techniques, on microtensile bond strength (µTBS) and marginal microleakage of composite resin restorations. MATERIAL AND METHODS: Extracted erupted human third molars were randomly divided into 4 groups. Dentin surfaces were treated with one of the following procedures: (A) 35 percent phosphoric acid gel (PA) + adhesive system (AS); (B) PA + 10 percent NaOCl + AS; (C) PA + oxalate + AS and (D) PA + oxalate + 10 percent NaOCl + AS. Bond strength data were analyzed statistically by two-way ANOVA and Tukey's test. The microleakage scores were analyzed using Kruskal-Wallis and Mann-Whitney non-parametric tests. Significance level was set at 0.05 for all analyses. RESULTS: µTBS data presented statistically lower values for groups D and B, ranking data as A>C>B>D. The use of oxalic acid resulted in microleakage reduction along the tooth/restoration interface, being significant when used alone. On the other hand, the use of 10 percent NaOCl alone or in combination with oxalic acid, resulted in increased microleakage. CONCLUSIONS: Dentin deproteinization with 10 percent NaOCl or in combination with oxalate significantly compromised both the adhesive bond strength and the microleakage at interface. Tubular occlusion prior to adhesive system application seems to be a useful technique to reduce marginal microleakage.