Efeito da ciclagem térmica na microinfiltração e microtração de restaurações de resina composta / Effect of thermal cycling on microleakage and µTBS of resin-composite restorations

O objetivo deste estudo foi avaliar a microinfiltração e a resistência de união à dentina por meio do teste de microtração em restaurações classe III, usando dois sistemas adesivos - o autocondicionante Clearfil SE Bond®/ Kuraray (SE) e o sistema de condicionamento ácido total Single Bond®/3MEspe (SB) -, submetidas (C) ou não à ciclagem térmica (NC). Foram preparadas duzentas cavidades classe III em incisivos bovinos, divididas em quatro grupos: G1:SB/NC; G2:SB/C; G3:SE/NC; G4:SE/C. Após restaurados, os G1 e G3 foram imersos em solução corante e os dentes, levados à cortadora metalográfica, sendo as restaurações seccionadas no sentido V-L em fatias de 0,7 a 0,8 mm. Essas secções foram, primeiramente, avaliadas quanto à penetração de corante e, em seguida, submetidas ao teste de microtração (área adesiva: 1 mm2), confeccionando-se espécimes em forma de "hourglass". Para os G2 e G4 as amostras foram submetidas a 2000 ciclos térmicos (5-55 ºC) e, após, sofreram os mesmos procedimentos descritos para os G1 e G3. Quanto à microinfilitração, os resultados foram analisados pelo teste de Kruskal-Wallis (p < 0,05), não demonstrando diferença estatisticamente significativa entre os grupos. Os dados de microtração (MPa) foram submetidos ao teste Anova dois fatores e Tukey (p < 0,05): G1:18,80a; G2:19,78a; G3:13,29c; G4:6,23b. Independentemente da ciclagem térmica, os dois adesivos apresentaram a mesma permissibilidade de microinfiltração. O desafio térmico influenciou negativamente na força de adesão do autocondicionante SE, mas não interferiu nos valores do SB.

The aim of this study was to evaluate the microleakageand μTBS of class III composite resin restoration using two bonding systems – the self etching primer Clearfil SE Bond/Kuraray (SE) and the one-bottle Single Bond/3MEspe (SB) subjected (C) or not (NC) to thermal cycles. 200 box-type class III cavities were prepared on surfaces of bovine incisors and divided into 4 groups: G1:SB/NC; G2:SB/C; G3:SE/NC; G4:SE/C. After the restorative procedures, G1 and G3 were immersed in a dye solution and the restorations were sectioned perpendicular to the cervical margin interface into 0.7± 0.2 mm thick slabs. These sections were first evaluated according to dye penetration and then the slabs were further trimmed at the interface to produce samples with a hourglass shape (cross-sectional surfacearea of 1mm2) to μTBS test evaluation. The samples ofG2 and G4 were thermocycled (2.000 cycles, 5-55 oC) and then subjected to the same procedures described for G1 and G3. The microleakage results were analyzed by the de Kruskal-Wallis (p < 0.05) test, and no differences were observed among groups. The μTBS means were analyzed by the Anova 2 way and Tukey test:G1:18.80a; G2:19.78a; G3:13.29c; G4:6.23b. Regardless the thermal cycles, both adhesive systems present the same microleakage results. However, for SE thermal cycling had adversely affected the bond strength values,but for SB no differences were observed.

Effect of the application time of self-etching primers on the bonding of enamel / 대한치과보존학회지

The purpose of this study was to compare the normal and two times of application time of six self-etching primers applied to enamel using microshear bond strength (uSBS) test and the finding of scanning electronic microscope (SEM). Crown of sixty human molars were bisected mesiodistally and buccal and lingual enamel of crowns were partially exposed and polished with 600 grit SiC papers. They were divided into one of two equal groups subdivided into one of six equal groups (n = 10) by self-etching primer adhesives. After the same manufacture's adhesive resin and composites were bonded on the enamel surface of each group, the bonded specimens were subjected to uSBS testing and also observed under SEM. In conclusion, generally two times of primer application time increased the enamel uSBS, especially with the statistical increase of bond strength in adhesives involving high-pH primers.

Influence of appication time of self-etching primers on dentinal microtensile bond strength / 대한치과보존학회지

This study evaluated the influence of application time of self-etching primers on microtensile bond strength (microTBS) to dentin using three self-etching primer adhesive systems. Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. microTBS was tested and statistically compared using by one-way ANOVA and Tukey's Test The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased microTBS to dentin.