350-356 Yip (new)

350 The excessive differential wear of teeth and restorative materials has significant deleterious effects on the biologic, functional, and esthetic condition of the masticatory system. However, controlled investigations of numerous factors that might influence tooth and restoration wear have been mainly laboratory studies, the findings of which might not correlate with either the physical properties of the substrates or clinical experience.1,2 Laboratory studies have examined the effects on restorative material wear of, for example, thermocycling,3 cyclic loading,4,5 applied load,6 degree of polymerization,7 aging,8 water absorption,9 lubricant pH,6,10 surface coatings,11–13 and toothbrushing/dentifrices.14 These studies have used twoand three-body wear simulation methods and various methods of measurement over widely differing time periods. Many laboratory studies have also examined the antagonistic wear of restorative materials and teeth.15–24 There have been far fewer laboratory studies of factors other than restorative materials that might influence tooth wear; these have mainly involved the examination of, for example, lubricant pH6,16 and the interplay between applied load and lubricants.25,26 Clinical studies of restoration wear have been mainly concerned with the development of more wear resistant and less abrasive posterior resin composites27 and, to a lesser extent, more wear resistant glass-ionomer cements (GIC)28 and less abrasive porcelains.2 Few studies have examined the in vivo antagonistic wear of restorative materials and teeth.29–32 Clinical studies of tooth wear have focused mainly on the effects of abrasive diets and parafunction,33,34 toothbrushing/dentifrices,35 and acid erosion.36 The purpose of this article is to discuss the clinical implications of differential wear between teeth and restorative materials.