title: Fracture resistance of tooth fragment reattachment: effects of different preparation techniques and adhesive materials.
abstract: The purpose of this study was to evaluate and compare the bond strengths of experimentally fractured human tooth fragments reattached with different adhesive materials and retentive techniques in vitro. Uncomplicated crown fractures were obtained on intact human mandibular permanent incisors by applying perpendicular load to the buccal aspect of tooth crowns. Fractured teeth were randomly assigned into one of three reattachment protocols: (i) Simple reattachment, (ii) Overcontour preparation, and (iii) Internal dentin groove. The first and second groups were divided into 10 subgroups, and the third group into five subgroups (n = 10 per group) with respect to five different adhesive systems (Prime&Bond NT, Adper Single Bond II, Adper Prompt L-Pop, Clearfil S(3) Bond, G Bond) used with or without a hybrid resin composite (Z250). Restored teeth were subjected to thermal cycling, and subsequently to the same loading protocol used for fracturing intact teeth. Fracture strength after reattachment procedures was recorded as a percentage of the original fracture strength. Both type of adhesive material and placement of an intermediate layer of resin composite affected the fracture resistance (P < 0.05). The highest fracture strength recovery was obtained using the internal dentin groove technique (54 +/- 0.58%, P < 0.05), followed by the overcontour and simple reattachment protocols (49 +/- 0.58% and 32 +/- 0.82%, respectively, P < 0.05). Ultramorphological evaluation of bonded specimens revealed voids and microcracks along the adhesive interface, which might contribute to postadhesive failure.
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
authors.forename: Esin
authors.initials: E
authors.lastname: Pusman
authors.forename: Zafer C
authors.initials: ZC
authors.lastname: Cehreli
authors.forename: Nil
authors.initials: N
authors.lastname: Altay
authors.forename: Bahtiyar
authors.initials: B
authors.lastname: Unver
authors.forename: Osman
authors.initials: O
authors.lastname: Saracbasi
authors.forename: Gungor
authors.initials: G
authors.lastname: Ozgun
mesh_terms: D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D007180:Incisor / Q000293:injuries; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D019228:Tooth Crown / Q000293:injuries; D014082:Tooth Fractures / Q000517:prevention & control / Q000628:therapy*; D019246:Tooth Preparation / Q000379:methods*
chemical_list: D003188:Composite Resins; C444701:Filtek Z250; D019279:Resin Cements