title: Effect of post adaptation on fracture resistance of endodontically treated teeth.
abstract: This study determined the effect of different post designs and varying amounts of post-to-canal adaptation on the fracture resistance of endodontically treated teeth. Forty freshly extracted maxillary central incisors were endodontically treated. Groups of 10 teeth were prepared according to four experimental designs. Cast post and cores and crowns were waxed, cast, and luted with zinc phosphate cement on a static loading device. The teeth were embedded in acrylic resin and the crowns were loaded on a universal testing machine at 130 degrees to the long axis of the tooth until failure. Maximum adaptation of the residual root structure with a tapered post significantly increases the fracture resistance of endodontically treated teeth, but upon failure renders the tooth nonrestorable. Tapered posts resulted in fractures that were directed more apically and lingually. Parallel-sided posts had a lower frequency of fracture upon failure, involving less tooth structure. Parallel-sided posts surrounded by large amounts of cement had no significant effect on failure loads.
authors.affiliation: University of California, School of Dentistry, Los Angeles.
authors.forename: J A
authors.initials: JA
authors.lastname: Sorensen
authors.forename: M J
authors.initials: MJ
authors.lastname: Engelman
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D003737:Dental Cavity Preparation; D003799:Dental Stress Analysis; D003779:Denture Design; D006801:Humans; D007180:Incisor; D011176:Post and Core Technique; D011475:Prosthesis Failure; D012044:Regression Analysis; D012390:Root Canal Therapy; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000209:etiology / Q000503:physiopathology*; D015036:Zinc Phosphate Cement
chemical_list: D015036:Zinc Phosphate Cement