title: Effect of cyclic loading on marginal adaptation and bond strength in direct vs. indirect class II MO composite restorations.
abstract: This study evaluated the effect of cyclic loading on the marginal adaptation and microtensile bond strength of direct vs indirect Class II composite restorations in an in-vitro model. Forty Class II cavities were prepared on the mesial surface of extracted human maxillary first premolars and divided into two groups: Group I--direct composite restorations and Group II--indirect composite restorations. Groups I and II were further divided into subgroups: A (without cyclic loading) and B (with cyclic loading of 150,000 cycles at 60N). The gingival margin of the proximal box was evaluated at 200x magnification for marginal adaptation in a low vacuum scanning electron microscope. The restorations were sectioned perpendicular to the bonded surface into 1 mm thickslabs. The slabswere further trimmed at the interface to produce a cross-sectional surface area of approximately 1 mm2. All specimens were subjected to microtensile bond strength testing. The marginal adaptation was analyzed using descriptive studies and bond strength data were analyzed by one-way ANOVA test. The indirect composite restorations performed better under cyclic loading.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Vivek
authors.initials: V
authors.lastname: Aggarwal
authors.forename: Ajay
authors.initials: A
authors.lastname: Logani
authors.forename: Veena
authors.initials: V
authors.lastname: Jain
authors.forename: Naseem
authors.initials: N
authors.lastname: Shah
mesh_terms: D000134:Acid Etching, Dental; D020906:Air Abrasion, Dental; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003736:Dental Cavity Lining; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D003793:Dental Restoration, Permanent / Q000145:classification*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007284:Inlays / Q000145:classification; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C115612:single bond; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate