title: Wear patterns in two amalgams and three posterior composites after 5 years' clinical service.
abstract: OBJECTIVE
  The purpose of this research was to evaluate the wear patterns of three posterior composites (Clearfil Posterior. Occlusin and P-30) and two amalgams (New True Dentalloy, Solila Nova) after 5 years' clinical service.
  
  
  METHODS
  Marginal wear was measured using the stepwedge technique which determines the maximal marginal wear by any one cusp together with the mean marginal value. The overall maximum depth of wear, occurring at any site on the occlusal surface, was determined using an impression technique with epoxy models.
  
  
  RESULTS
  The mean values (+/- standard deviations) for the overall maximum wear were: New True Dentalloy, 203 +/- 98 microns; Solila Nova, 200 +/- 96 microns; Clearfil Posterior, 252 +/- 141 microns; Occlusin, 324 +/- 189 microns; P-30, 380 +/- 273 microns. These values were significantly different (ANOVA F = 2.86 P = 0.05). There was no correlation between the marginal scores and the overall maximum depth of wear (P > 0.05). There was no correlation between the marginal scores and the overall maximum depth of wear (P > 0.05). With some restorations the maximum wear occurred at the margins, marginal ridges or cavity extensions rather than sites of occlusal contact.
  
  
  CONCLUSIONS
  After 5 years' service the overall wear of three posterior composites exceeded that of two amalgams; however, for a number of restorations the difference was not significant. Marginal wear values cannot be used to predict the overall maximal depth of wear.
authors.affiliation: Department of Clinical Dental Sciences, University of Liverpool, UK.
authors.forename: L H
authors.initials: LH
authors.lastname: Mair
mesh_terms: D001641:Bicuspid; D003188:Composite Resins; D003722:Dental Alloys; D003723:Dental Amalgam; D003766:Dental Occlusion; D003793:Dental Restoration, Permanent / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D008963:Molar; D019279:Resin Cements; D013499:Surface Properties; D014520:Urethane
chemical_list: D003188:Composite Resins; D003722:Dental Alloys; D019279:Resin Cements; C056413:Occlusin; C072651:Solilanova; C048711:P-30 composite resin; C031359:New True Dentalloy; D014520:Urethane; D003723:Dental Amalgam; C072674:Clearfil Posterior