Evaluation of resin composite materials. Part II: in vivo investigations

To clinically evaluate two different resin-based composites (Solitaire I and Ariston pHc) in order to determine the minimum clinical evaluation time needed to detect critical signs of failure.

In a controlled prospective clinical study, 99 cavities (30 Class I, 69 Class II) in 31 patients were restored (50 Ariston pHc without enamel etching and rubber dam, 49 Solitaire I restorations with total etching and rubber dam) and clinically investigated at baseline, after 6, 12, and 24 months.

After 2 years of clinical service, 49 restorations (Ariston pHc: n = 38, Solitaire: n = 11) had to be replaced. The majority of failures occurred after more than 1.5 years. The reasons for replacement were differently distributed in both groups (Ariston pHc: 28 tooth fractures, 3 gap formations, 5 hypersensitivities, 1 bulk fracture, 1 marginal fracture. Solitaire: 5 gap formations, 1 hypersensitivity, 3 bulk fractures, 1 wear of the restorative material, 1 void in the restoration). Forty-four restorations were still in function after 2 years (overall failure rate after 2 years: 14%; Ariston pHc: 17%; Solitaire: 7%; survival analysis algorithm according to Kaplan/Meier). Comparing the materials, no statistical differences were evident except for the criteria "integrity tooth" (= tooth fracture or cracks) and "hypersensitivity" (from the 12-month recall; Mann-Whitney U-test; P< 0.05). In both cases of significant difference, Ariston pHc exhibited inferior results. After 2 years, only three teeth restored with Ariston pHc did not show considerably cracked enamel. The additional marginal analysis showed statistically significant differences for both materials regarding the criteria "perfect margin" (decrease), "gap formation" (increase), and "negative step formation" (increase; P< 0.05; Friedman 2-way ANOVA) between the four recalls. Therefore, a 2-year in vivo evaluation should be recommended prior to marketing a dental restorative material.