WEAR PATTERNS IN 2 AMALGAMS AND 3 POSTERIOR COMPOSITES AFTER 5 YEARS CLINICAL SERVICE

Objectives: The purpose of this research was to evaluate the wear patt erns 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 stepw edge technique which determines the maximal marginal wear by any one c usp together with the mean marginal value. The overall maximum depth o f wear, occurring at any site on the occlusal surface, was determined using an impression technique with epoxy models. Results: The mean val ues (+/- standard deviations) for the overall maximum wear were; New T rue Dentalloy, 203 +/- 98 mu m; Solila Nova, 200 +/- 96 mu m; Clearfil Posterior, 252 +/- 141 mu m; Occlusin. 324 +/- 189 mu m; P-30, 380 +/ - 273 mu m. These values were significantly different (ANOVA F = 2.86 P = 0.05). There was no correlation between the marginal scores and th e overall maximum depth of wear (P > 0.05). With some restorations the maximum wear occurred at the margins, marginal ridges or cavity exten sions rather than sites of occlusal contact. Conclusions. After 5 year s' service the overall wear of three posterior composites exceeded tha t of two amalgams: however, for a number of restorations the differenc e was not significant. Marginal wear values cannot be used to predict the overall maximal depth of wear.