Resistência à fratura de dentes reforçados com pinos pré-fabricados, utilizando diferentes agentes cimentantes

O estudo comparou in vitro a resistencia a fratura em dentes tratados endodonticamente reforcados com pinos intra-radiculares pre-fabricados, utilizando diferentes agentes cimentantes. Cinquenta dentes humanos permanentes unirradiculares obturados, foram divididos em 5 grupos: G I-controle (sem pino); G II- pino de fibra de carbono + cimento Rely X; G III- pino de fibra de carbono + cimento Enforce; G IV- pino de fibra de vidro + cimento Rely X; G V- pino de fibra de vidro + cimento En-force. Apos cimentacao dos pinos e restauracao coronal, as raizes foram incluidas em resina acrilica quimicamente ativada e submetidos a carga de compressao em uma Maquina Universal de Ensaios (Instron 5582). Os dados obtidos foram analisados estatisticamente pelos testes Exato de Fisher e o teste F (ANOVA), a um nivel de signifcância de 5,0%, os quais demonstraram que em relacao ao local da interface no grupo total, a maioria (67,5%) das amostras teve fratura na interface dente/agente cimentante; destacou-se tambem que a frequencia de fraturas no dente/agente cimentante variou de 4 (grupo V) a 10 (grupo III), diferencas estas significante entre os grupos. Concluiu-se que o uso dos pinos pre-fabricados nao proporcionou aumento na resistencia dos dentes tratados endodonticamente; o pino de fibra de vidro em associacao ao sistema Enforce mostrou-se superior na resistencia a fratura, sendo estatisticamente signifcante quando comparado ao grupo Enforce / pino de fibra de carbono; em relacao a resistencia de uniao, o maior comprometimento se deu na interface agente cimentante/dente quando comparada ao agente cimentante/pino. The study compared in vitro the resistance to fracture of teeth endodontically treated reinforced with prefabricated intra-radicular posts, cemented with diferent cementation agents. Fifty permanents human teeth which had only one root was filled and divided in five groups: G I- control (without pin); G II carbon-fiber post + Rely X cement; G III carbon-fiber post + Enforce cement; G- IV fiber core post + Rely-X cement; G-V f- ber core post + Enforce cement. After cementation of this posts and coronal restoration, the root was included in self-activated acrylic resin and was submited to compressive axial loading in a Universal Testing Machine (Instron 5582). The results were statistically analyzed by Exato de Fisher test and test F (ANOVA), with 5,0 % signifcance, which demonstrated that in relation to the interface place in the total group, the majority (67,5%) of the samples had fracture on interface tooth/cementation agent ; the frequency of fractures on teeth/cementation agent varied from 4 (group V) to 10 (group III), and these diferences were significant among the groups. It was concluded that the use of prefabricated intra radicular posts couldn´t intensify the resistance of endodontically treated teeth; fiber core post associated to Enforce cement was more resistant to fracture, and statistically significant than carbon-fiber post and Enforce cement group. About bond strength the interface cement agent/teeth was less resistant than cement agent/pin.