Avaliação da resistência à união dentinária entre tratamento ultra-sônico e alta rotação na interface dente/material restaurador

• Autor(a) principal: Conde, Alexandre
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/430
• topic: ODONTOLOGIA; RESISTÊNCIA DOS MATERIAIS (ODONTOLOGIA); DENTINA; ADESIVOS DENTÁRIOS

Seventeen extracted healthy third molars were used in order to evaluate dentine as to: microtensile bond strength (μTBS) with Z250 resin composite (CR), and 3M Single Bond 2 adhesive; appearance previous to adhesive treatment (APTA); adhesive union (UA); type of fracture by Scanning Electron Microscope (SEM), and energy dispersion spectroscopy (EDS), comparing the treatment with a KGSorensen diamond bur (PD) and a CVDentus (UT) ultrasound tips with (c/a) and without (s/a) etching. Four groups (n=40) were divided according to the dentin processing (PDs/a - diamond bur without etching); (PDc/a - diamond bur with etching); (UTs/a - ultrasound tip without etching); (UTc/a - ultrasound tip with etching) were restored, embedded in politetrafluoretilene tube using chemically activated acrylic resin, and sectioned into samples for μTBS testing in an EMIC DL-2000 universal machine (0. 5 mm/min). Samples were analyzed by SEM and EDS for fracture classification UA and APTA. Statistical tests were: Kolmogorov- Smirnov Test; Two way Variance Analysis; Tukey and Fisher's Exact Test (p≤0,05). Failures were classified as: cohesive in dentine (CD); cohesive in CR (CM); cohesive interfacial on the base or top of hybrid layer (CBT); adhesive cohesive interfacial (CA); mixed (M); interfacial on smear layer (S). Results showed (group, average μTBS in MPa - standard deviation): (UTc/a, 45. 31-8. 16); (PDc/a, 34. 04-9. 29); (UTs/a, 15. 17-3. 71); (PDs/a, 9. 86-3. 80).The PD method is associated to CBT, and the UT method is associated to CA and CM; c/a is associated to CBT and CM, and s/a is associated to S. APTA showed: PDs/a - total obstruction of dentinal tubules (cd); UTs/a - partial disobstruction of cd and irregular surface appearance; PDc/a - complete disobstruction of cd; UTc/a - complete disobstruction of cd, and irregular surface appearance. UA showed: PDs/a rectilinear hybrid layer occurred without tags penetration (PT); UTs/a, curvilinear with a few PT; PDc/a, rectilinear with PT; UTc/a, curvilinear with PT. It was concluded that the association of UTc/a treatment promotes higher values of μTBS. There is an association between CBT failure and the PD method, failures CA and CM and the UT method, failures CBT and CM and the c/a method, and failure S and the s/a method. The failures that caused higher resistance to its rupture were, in a decreasing order: CD; CM; CBT; CA; M, and S.