title: Interferometric measurements of cusp deformation of teeth restored with composites.
abstract: A Michelson interferometry apparatus was used for measurement of the displacement of the buccal cusps of premolars after restoration of MOD preparations with composites. The effects of composite type, cavity size, and hydration conditions were examined. Interferometry permitted real-time measurement of cusp movement as it occurred. Contraction occurred very rapidly, about 1/3 of the 60-minute amount within the two-minute period of exposure to the curing light. Cusp movement was smooth rather than interrupted, indicating lack of microfracturing at deformations of 11-46 microns. Contraction, 0.94% for Heliomolar and 1.2% for P-50, was similar to the linear polymerization shrinkage of the resins. Less cusp movement occurred in small cavities than in large cavities. Hydrated teeth had less cusp movement than dehydrated teeth.
authors.affiliation: Department of Conservative Dentistry, College of Dentistry, University of Mosul, Iraq.
authors.forename: A A
authors.initials: AA
authors.lastname: Suliman
authors.forename: D B
authors.initials: DB
authors.lastname: Boyer
authors.forename: R S
authors.initials: RS
authors.lastname: Lakes
mesh_terms: D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000737:chemistry*; D003737:Dental Cavity Preparation / Q000379:methods; D003743:Dental Enamel / Q000502:physiology* / Q000648:ultrastructure*; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007368:Interferometry; D011108:Polymers / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements; D013314:Stress, Mechanical; D013499:Surface Properties; D014867:Water
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C513708:Heliomolar; D011108:Polymers; D011140:Polyurethanes; D019279:Resin Cements; D014867:Water; C065771:P50 composite resin; D017438:Bisphenol A-Glycidyl Methacrylate; C041330:Scotchbond