Efeito das variações do pH na resistência de união e na nanoinfiltração de sistemas adesivos à dentina

• Autor(a) principal: Manfroi, Fernanda Borguetti
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/7879
• topic: Ciclos de pH; Dentina; Resistência de União; Sistemas Adesivos; CIENCIAS DA SAUDE::ODONTOLOGIA

(Artigo 1 - Efeito dos ciclos de pH na resistência de união de diferentes sistemas adesivos à dentina) Purpose: To verify the influence of the pH cycles on the microtensile bond strength (μTBS) to dentin of three adhesive systems compared to the immediate μTBS and after storage in artificial saliva for 6 months. Materials and methods: The occlusal surface of 32 sound third molar teeth was removed to obtain a flat dentin surface. The teeth were randomly divided into four groups (n=8/group): G1 - Single Bond Universal in the total-etch mode; G2 – Single Bond Universal in the self-etch mode; G3 – Scotchbond Multi Purpose (totaletch mode control); G4 – Clearfil SE Bond (self-etch mode control). A block of composite with 6 mm height was built on the adhesive area. After 24 h of storage in distilled water at 37°C, the tooth/resin sets were cut parallel to the long axis of the tooth, in the x and y directions, with a section of approximately 0.8 mm2 . Fifty-two specimens were obtained for each group, of which 26 were submitted to pH cycles and the other 26 were stored in artificial saliva for 6 months. Subsequently, the specimens were submitted to a μTBS test in a universal testing machine at a crosshead speed of 0.5 mm/min. For the immediate evaluation (24 h), results previously obtained were used for this study. Results: According to the two-way ANOVA test, the interaction between the factors (p=0.0001) was significant. There was no significant difference in the immediate μTBS between the adhesive systems. After 4 cycles of pH and 6 months of storage in artificial saliva, there was a significant decrease in μTBS for all adhesive systems. The failures were predominantly mixed. Conclusion: The pH cycles and the storage in artificial saliva for 6 months were detrimental to the stability of the bonding interface. (Artigo 2 - Efeito dos ciclos de pH na nanoinfiltração de diferentes sistemas adesivos à dentina) Purpose: To verify the influence of the pH cycles on the nanoleakage in the dentin-adhesive interface of three adhesive systems compared to the immediate nanoleakage and after storage in artificial saliva for 6 months. Materials and methods: The occlusal surface of 24 sound third molar teeth was removed to obtain a flat dentin surface. The teeth were randomly divided into four groups (n=6/group): G1 – Single Bond Universal in the total-etch mode; G2 – Single Bond Universal in the self-etch mode; G3 – Scotchbond Multi Purpose (total-etch mode control); G4 – Clearfil SE Bond (self-etch mode control). A block of composite with 6 mm height was built on the adhesive area. After 24 h of storage in distilled water at 37°C, the tooth/resin sets were cut parallel to the long axis of the tooth to obtain slices with a thickness of approximately 1.0 mm. Three slices of the central region of each tooth were obtained. One slice was submitted to pH cycles, and one slice was stored in artificial saliva for 6 months. The nanoleakage methodology was applied. Images of the dentin-adhesive interfaces were obtained by scanning electron microscopy (2000x), and the images were analyzed in the ImageJ program to evaluate the percentage of nanoleakage area (%N). Results: According to the two-way ANOVA test, the interaction between the factors (adhesive system x storage) (p=0.0001) was significant. There was no significant difference in the %N between the adhesive systems at 24 h. After the pH cycles, the adhesive systems applied in the self-etch mode obtained lower %N, differing significantly from total-etch adhesives. After 6 months in artificial saliva, there was lower %N compared to pH cycles, and the lowest %N occurred in self-etch adhesives. Conclusion: The pH cycles caused higher nanoleakage than storage in artificial saliva for 6 months. The self-etch adhesive systems had lower nanoleakage after pH cycles and storage in artificial saliva for 6 months in relation to total-etch adhesive systems.