Influência da terapia endodôntica e do envelhecimento artificial acelerado na resistência de união de pinos de fibra de vidro à dentina intrarradicular

• Autor(a) principal: Santana, Fernanda Ribeiro
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/4270
• topic: Pino de fibra de vidro; Resistência de união; Dentina radicular; Instrumentação; Irrigantes; Cimento endodôntico; Envelhecimento; Fibreglass post; Bond strength; Root dentine; Instrumentation; Irrigants; Endodontic sealer; Aging; CIENCIAS DA SAUDE::ODONTOLOGIA

Aim: To evaluate in vitro the influence of root canal instrumentation techniques, endodontic irrigants, endodontic sealers and artificial accelerated aging on fibreglass post bond strength to bovine intraradicular dentine. Methodology: Part 1. 120 bovine incisors were divided into 12 experimental groups (n=10) resulting from the interaction among 3 study factors: root canal instrumentation technique (RCPSS- root canal preparation with stainless steel instruments - KFile; RCPNiTi- root canal preparation with K3 Nickel-Titanium instruments), endodontic irrigant (NaOCl- 1% sodium hypochlorite; CHX- 2% chlorhexidine; O3- 1.2% ozonated water) (in all samples 17% EDTA was used to remove the smear layer) and specimens artificial accelerated aging (Immediate, test with no aging; Mediate, test performed after 2 months of water storage at 37°C). After root canal preparation, endodontic filling was not performed. Fibreglass posts were cemented with self-adhesive resin cement (RelyX U100, 3M-ESPE) and roots were cross-sectioned to obtain two slices of each third. Samples were submitted to micropush-out test and bond strength values (MPa) were analyzed by ANOVA in a split-plot arrangement and Tukey’s test (α = 0.05). Failure modes were evaluated under a confocal microscope. Part 2. 60 bovine incisors were divided into 6 experimental groups (n=10) resulting from the interaction between 2 study factors: endodontic sealer (Sx- Sealapex; S26- Sealer 26; AHAH Plus) and specimens artificial accelerated aging (Immediate, test with no aging; Mediate, test performed after 2 months of water storage at 37°C). Two control groups were employed (without root canal filling), represented by groups RCPNiTiNaOCl immediate and RCPNiTiNaOCl mediate of part 1 of the present study. In the six experimental groups, root canals were prepared 1mm from the apex with K3 Nickel-Titanium instruments associated with 1% sodium hypochlorite irrigation and 17% EDTA. They were then filled with gutta-percha and the specific sealer of each group, using the lateral compaction technique. Fibreglass posts were cemented with self-adhesive resin cement (RelyX U100, 3M-ESPE) and roots were cross-sectioned to obtain two slices of each third. Abstract xx Samples were submitted to micropush-out test and bond strength values (MPa) were submitted to ANOVA in a split-plot arrangement and Tukey’s test (α = 0,05). Comparisons with control groups were made using Dunnet test (α = 0.05). Failure modes were evaluated under a confocal microscope. Results: Part 1. In specimens submitted to water artificial aging, RCPNiTi presented higher bond strength values than RCPSS in apical third irrigated with NaOCl or CHX. Irrigation with NaOCl resulted in higher bond strength than O3. Artificial aging resulted in significant bond strength increase, except for middle and apical thirds of RCPSSO3 and apical of RCPNiTiO3. Bond strength significantly reduced in apical third. The prevalence of adhesive cement-dentine failure was verified in all groups. Part 2. Endodontic sealers showed no significant differences among them, however they presented significantly lower bond strength values than control groups (without filling), except in cervical third of groups tested immediately. Artificial aging did not interfere on bond strength to intraradicular dentine. There was a significant decrease on bond strength from cervical to apical third. The prevalence of adhesive cement-dentine failure was verified in all groups. Conclusions: Part 1. Root canal preparation with NiTi instruments associated with NaOCl irrigation and EDTA increased the bond strength of fiberglass posts cemented with self-adhesive resin cement to intraradicular dentine. Part 2. Endodontic sealers interfered negatively on bonding of fibreglass posts cemented with self-adhesive resin cement to intraradicular dentine.