Aplicação de sistemas adesivos à dentina irradiada com laser de Nd:YAG: estudo da durabilidade da resistência de união

• Ano de defesa: 2006
• Autor(a) principal: Heredia, Alexandre Rodriguez
• Orientador(a): Spohr, Ana Maria
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre
• Palavras-chave em Português: ODONTOLOGIA; LASER - ODONTOLOGIA; ADESIVOS DENTÁRIOS; DENTINA
• Link de acesso: http://hdl.handle.net/10923/362

The purpose of this study was to evaluate, in vitro, the influence of Nd:YAG laser in bond strength of the Single Bond 2 and Clearfil SE Bond adhesive systems to dentin, as well as durability of such bond, and superficial topography of the laser irradiated dentin. A flat occlusal surface was obtained in extracted third human molars being it regulated with 320, 400 and 600 grit silicon carbide sandpaper, respectively. Teeth were randomly divided in 8 groups: Group 1 - Single Bond 2; Group 2 - Clearfil SE Bond; Group 3 – laser and Single Bond 2; Group 4 – laser and Clearfil SE Bond. Nd:YAG laser was applied in dentin previously to adhesive system in the following parameters: 60mJ, 15Hz and 0,9W. After applying adhesive systems, composite resin blocks with 6 mm height were built. Samples from these groups were stored in distilled water at 37º C for 24 hours. Samples from Groups 5, 6, 7 and 8 were identical to Groups 1, 2, 3 and 4, respectively, being stored in distilled water at 37º C for 7 months. After storage period, groups of tooth/resin were cut in a parallel way along the tooth axis in buccal-lingual and mesio-distal directions with cut of approximately 0,7 mm. It was obtained 25 specimens for each group, being, then, submitted to microtensile bond strength on a universal testing machine at a crosshead speed of 0,5mm/min. Superficial topography of dentin with laser application was observed in MEV. According to Variance Analysis and Tukey test (a=0,05), group 1 (Single Bond 2, 24 h = 19,79 MPa), group 5 (Single Bond 2, 7 months = 21,58 MPa), and group 7 (Single Bond 2, with laser, 7 months = 17,80 MPa) did not differ statistically amongst and were statistically higher than all Clearfil SE Bond groups. For Single Bond 2, the lowest mean was obtained by group 3 (Single Bond 2, with laser, 24 hours = 12,44 MPa), not statistically differing from group 7 (Single Bond 2, with laser, 7 months). The lowest means were obtained with Clearfil SE Bond groups, which did not statistically differ amongst, being obtained the following means: group 2 (11,39 MPa), group 4 (10,60 MPa), group 6 (11,16 MPa) and group 8 (9,56 MPa). According to analysis in MEV, Nd:YAG laser altered dentin superficial topography. It was concluded that Nd:YAG laser significantly reduced resistance to microtensile bond strength only for Single Bond 2 adhesive system when stored for 24 hours, and that laser did not significantly implicate bond durability in a period of 7 months for tested adhesive systems.