Influência da presença e do tipo de retentor intrarradicular no comportamento em fadiga de incisivos centrais restaurados com coroas totais
Carregando...
Arquivos
Data
2019-01-07
Autores
de Andrade, Guilherme Schmitt [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Este estudo avalia a influência da presença e tipo de pinos e núcleos na sobrevivência à fadiga de incisivos centrais restaurados com coroas totais. As coroas de 69 incisivos bovinos foram cortadas e as raízes tratadas endodonticamente. As raízes foram distribuídas aleatoriamente em três grupos (n = 23): núcleo de resina composta (NRC), núcleo de resina composta retido por pino de fibra de vidro (PFV) e núcleo metálico fundido (NMF). Todos receberam preparo de coroa total com férula de 2 mm, e então, uma coroa de cerâmica reforçada com leucita foi adesivamente cimentada. Três amostras de cada grupo foram testadas para determinação da carga máxima até a falha. As amostras restantes foram carregadas pelo teste acelerado de fadiga stepwise stress até a fratura ou suspensão após o término de 1,5 x 106 ciclos. A carga e o degrau em que cada espécime falhou foram analisadas pela estatística de Kaplan-Meier e Mantel-Cox (Log Rank test), seguidas por comparação múltipla aos pares, com nível de significância de 5%. O modo de falha foi analisado com estéreomicrocópio. Não houve diferença estatística entre os tratamentos quanto à carga (Mantel-Cox Log-Rank test for trend, X2=0,015, df=1, p=0,901), nem para o número de ciclos (Mantel-Cox Log-Rank test for trend, X2 =3,171, df=1, p=0,995). O modo de falha predominante foi a trinca da coroa. Fratura obliqua da raiz só foi observado nos grupos retidos por pinos. Nos incisivos tratados endodonticamente com férula de 2 mm, a presença e o tipo de pino e núcleo não influenciaram na sobrevida em fadiga. Fraturas não restauráveis ocorreram somente em dentes restaurados com pinos.
This study evaluates the influence of presence and type of post-and-core systems on fatigue survival of non-vital central incisors restored with all-ceramic crowns. The crowns of 69 bovine incisors were cut and endodontically treated. The roots were randomly assigned into three groups (n=23): composite resin build-up (NRC), glass fiber post-retained-composite build-up (PFV) and cast post-and-core (NMF). All specimens received crown preparation with a 2 mm ferrule, and then a leucite-reinforced ceramic crown was adhesively cemented. Three samples from each group were tested for the determination of the maximum load to failure. The remaining samples were loaded by the accelerated fatigue stepwise stress test until fracture or suspension after the end of 1.5 x 106 cycles. The load and the step on which each specimen failed were analyzed by the Kaplan-Meier and Mantel-Cox (Log Rank test) statistics, followed by multiple paired comparisons, with a significance level of 5%. The failure mode was analyzed with stereomicroscope. There was no statistically significant difference between the treatments (Mantel-Cox Log-Rank test for trend, X2=0.015, df=1, p=0.901), nor for the number of cycles (Mantel-Cox Log-Rank test for trend, X2=3.171, df=1, p=0.995). The predominant failure mode was the crown crack. Oblique root fracture was observed only in groups retained by posts. The presence and type of post system did not influence the fatigue survival of the endodontically treated incisors with a 2 mm ferrule. Non-restorable fractures only occurred on teeth restored with posts.
This study evaluates the influence of presence and type of post-and-core systems on fatigue survival of non-vital central incisors restored with all-ceramic crowns. The crowns of 69 bovine incisors were cut and endodontically treated. The roots were randomly assigned into three groups (n=23): composite resin build-up (NRC), glass fiber post-retained-composite build-up (PFV) and cast post-and-core (NMF). All specimens received crown preparation with a 2 mm ferrule, and then a leucite-reinforced ceramic crown was adhesively cemented. Three samples from each group were tested for the determination of the maximum load to failure. The remaining samples were loaded by the accelerated fatigue stepwise stress test until fracture or suspension after the end of 1.5 x 106 cycles. The load and the step on which each specimen failed were analyzed by the Kaplan-Meier and Mantel-Cox (Log Rank test) statistics, followed by multiple paired comparisons, with a significance level of 5%. The failure mode was analyzed with stereomicroscope. There was no statistically significant difference between the treatments (Mantel-Cox Log-Rank test for trend, X2=0.015, df=1, p=0.901), nor for the number of cycles (Mantel-Cox Log-Rank test for trend, X2=3.171, df=1, p=0.995). The predominant failure mode was the crown crack. Oblique root fracture was observed only in groups retained by posts. The presence and type of post system did not influence the fatigue survival of the endodontically treated incisors with a 2 mm ferrule. Non-restorable fractures only occurred on teeth restored with posts.
Descrição
Palavras-chave
Fadiga, Técnica para retentor intrarradicular, Dente tratado endodonticamente, Coroas dentárias, Fatigue, Fatigue, Post and core technique, Endodontically treated teeth, Crowns