title: Effect of reinforcement with resin composite on fracture strength of structurally compromised roots.
abstract: This study was aimed at evaluating the fracture resistance of structurally compromised roots restored with four different post and core systems. Thirty-two bovine roots were uniformly shaped to simulate human mandibular premolar roots. The roots were divided into four groups based on the type of restoration: cemented cast post and core (Group MC), resin composite build-up (Group CR), resin composite and prefabricated glass fiber post build-up (Group FRC), and thick-layer dual-cured resin composite-reinforced small-diameter tapered cast post and core (Group CRM). After a static loading test, the failure mode and fracture resistance were recorded. Group CRM (719.38+/-196.73 N) exhibited a significantly high fracture resistance compared with the other groups (Group MC: 429.56+/-82.43 N; Group CR: 349.56+/-66.21 N; Group FRC: 398.94+/-112.71 N; p<0.05). In conclusion, Group CRM exhibited better mechanical properties for structurally compromised roots with no ferrules, although all types of restorations showed non-restorable fracture modes.
authors.affiliation: Fixed Prosthodontics, Department of Restorative Sciences, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan. fukui.fpro@tmd.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fukui
authors.forename: Wataru
authors.initials: W
authors.lastname: Komada
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Shiho
authors.initials: S
authors.lastname: Otake
authors.forename: Daizo
authors.initials: D
authors.lastname: Okada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miura
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000627:therapeutic use*; D003786:Dental Pulp Cavity / Q000473:pathology; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D004195:Disease Models, Animal; D055119:Elastic Modulus; D011176:Post and Core Technique / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000473:pathology* / Q000517:prevention & control; D014092:Tooth Root / Q000473:pathology*; D019553:Tooth, Nonvital / Q000473:pathology
chemical_list: D003188:Composite Resins