title: Cervical Interfacial Bonding Effectiveness of Class II Bulk Versus Incremental Fill Resin Composite Restorations.
abstract: Cervical interfacial bonding quality has been a matter of deep concern. The purpose of this study was to analyze microtensile bond strength (MTBS) and cervical interfacial gap distance (IGD) of bulk-fill vs incremental-fill Class II composite restorations. Box-only Class II cavities were prepared in 91 maxillary premolars (n = 7) with gingival margin placement 1 mm above the cementoenamel junction at one side and 1 mm below it on the other side. Eighty-four maxillary premolars were divided into self-etch and total-etch groups and further subdivided into six restorative material subgroups used incrementally and with an open-sandwich technique: group 1, Tetric Ceram HB (TC) as a control; group 2, Tetric EvoFlow (EF); group 3, SDR Smart Dentin Replacement (SDR); group 4, SonicFill (SF); group 5, Tetric N-Ceram Bulk Fill (TN); and group 6, Tetric EvoCeram Bulk Fill (TE). Groups 2-6 were bulk-fill restoratives. Tetric N-Bond Self-Etch (se) and Tetric N-Bond total-etch (te) adhesive were used in subgroups 1-5, whereas AdheSE (se) and ExciTE F (te) were used in subgroup 6. In an additional group, Filtek P90 Low Shrink Restorative (P90) was used only with its corresponding self-etch bond. The materials were manipulated, light-cured (1600 mW/cm(2)), artificially aged (thermal and occlusal load-cycling), and sectioned. Two microrods/restoration (n = 14/group) were tested for MTBS at a crosshead-speed of 0.5 mm/min (Instron testing machine). Fracture loads were recorded (Newtons), and MTSBs were calculated (Megapascals). Means were statistically analyzed by the Kruskal-Wallis test, Conover-Inman post hoc analysis for MTBS (multiple comparisons), and Mann-Whitney U test for IGD. The ends of the fractures were examined for failure mode. One microrod/restoration (n = 7/group) was investigated by scanning electron microscopy (×1200) for IGD. MTBS values for SF/te, P90 in enamel, and TC+SDR/te in enamel and cementum were significantly higher compared with those for the control TC/te and TC/se in cementum. Most of the failures were mixed. IGDs were generally smaller at enamel margins, and the smallest IGDs were found in P90 at both enamel and cementum margins. Bulk-fill and silorane-based composites might provide better cervical interfacial quality than incremental-fill restorations.
authors.forename: F
authors.initials: F
authors.lastname: Al-Harbi
authors.forename: D
authors.initials: D
authors.lastname: Kaisarly
authors.forename: A
authors.initials: A
authors.lastname: Michna
authors.forename: A
authors.initials: A
authors.lastname: ArRejaie
authors.forename: D
authors.initials: D
authors.lastname: Bader
authors.forename: M
authors.initials: M
authors.lastname: El Gezawi
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry*; D017213:Root Caries / Q000628:therapy; D013718:Tensile Strength; D019237:Tooth Cervix
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements