title: Cusp movement in premolars resulting from composite polymerization shrinkage.
abstract: This study examined the effect of cavity size, hydration conditions and type of composite on cusp movement following placement of MOD composite restorations in vitro. A microscope with a micrometer stage was used to measure deflection of cusps for 14 days after initiation of curing. The intercuspal width decreased for the first few minutes after the composites were placed, then increased toward the original dimensions. Teeth with small cavities contracted less than those with large cavities, and recovery was complete or nearly complete only in teeth with small cavities. Hydrated teeth and restorations recovered more rapidly and more completely than those that were dry. Differences in deflection of the cusps were observed with two different restorative materials.
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: D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D001641:Bicuspid / Q000503:physiopathology*; D017438:Bisphenol A-Glycidyl Methacrylate; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003188:Composite Resins / Q000737:chemistry*; D003737:Dental Cavity Preparation; D003793:Dental Restoration, Permanent; D003890:Desiccation; D006801:Humans; D011140:Polyurethanes / Q000737:chemistry*; D014867:Water
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes; D014867:Water; C065771:P50 composite resin; D017438:Bisphenol A-Glycidyl Methacrylate