title: Cuspal deflection in premolar teeth restored using current composite resins with and without resin-modified glass ionomer liner.
abstract: OBJECTIVE
  To evaluate the effects of four different types of composite resins and a resin modified glass ionomer cement (RMGIC) liner on the cuspal deflection of large MOD cavities in vitro.
  
  
  METHODS
  One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized large MOD cavities were prepared. The distance between cusp tips was measured before and after the cavity preparations with a digital micrometer. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P60, Filtek Z250, Filtek Silorane - 3M ESPE, St Paul, MN, USA) with and without a RMGIC liner (Vitrebond, 3M ESPE, St Paul, MN, USA). Cuspal deflection was measured 5 min, 24 h, and 48 h after the completion of restorations. The data were statistically analyzed with Friedman and Kruskal Wallis tests.
  
  
  RESULTS
  A significant reduction in cuspal deflection was observed in Filtek Silorane restorations with and without RMGIC liner (p<0.05). In all restored teeth, the distance between cusps was reduced but they did not return to their original positions during the 48 h period. All teeth showed cuspal deflection, but placement of RMGIC liner reduced it.
  
  
  CONCLUSIONS
  The use of silorane-based composites and the placement of RMGIC liner under the composite resin restorations resulted in significantly reduced cuspal deflection.
authors.affiliation: Faculty of Dentistry, Department of Conservative Dentistry, Ondokuz Mayıs University, Kurupelit, Samsun, Turkey. dtemelc@yahoo.com
authors.forename: E
authors.initials: E
authors.lastname: Karaman
authors.forename: G
authors.initials: G
authors.lastname: Ozgunaltay
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001641:Bicuspid / Q000033:anatomy & histology*; D003188:Composite Resins / Q000737:chemistry*; D003736:Dental Cavity Lining / Q000379:methods*; D003737:Dental Cavity Preparation / Q000145:classification; D003738:Dental Cements / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000379:methods*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry*; D062047:Silorane Resins / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D019228:Tooth Crown / Q000033:anatomy & histology*
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; C467913:Filtek Flow; C438835:Filtek P60 Composite Resin; C474035:Filtek Supreme; C444701:Filtek Z250; D005899:Glass Ionomer Cements; D019279:Resin Cements; D062047:Silorane Resins; C555513:silorane composite resin; C067790:Vitrabond