Clinical evaluation of stress-reducing direct composite restorations in structurally compromised molars: a 2-year report.

OBJECTIVE: To evaluate the clinical performance of class II large-size direct composite restorations.

MATERIALS AND METHODS: Fifty (50) patients 18 years or older were included in this clinical trial restoring 75 vital molar teeth with large-size cavities.

INCLUSION CRITERIA: Occlusal extension greater than two-thirds the intercuspal distance and proximal extension greater than half the distance between line angles. Teeth with residual cavity walls less than 1 mm and with one or more cusps involved were excluded. Teeth were randomly divided in three groups. Group 1: Opti-Bond FL; group 2: Scotchbond 1 XT; group 3: PQ1. Total-etching was performed using 35% phosphoric acid followed by the application of 2% chlorhexidine gluconate in the three groups. All teeth were restored using Vit-l-escence microhybrid composite resin. The proximal surface was built up first, followed by dentin and enamel occlusal surface stratification; wedge-shaped increments of composite resin were placed and cured using the UltraLume V curing light through a combination of pulse and progressive curing techniques.

RESULTS: Restorations were evaluated at six-month intervals during the two-year period using a modified US Public Health Service criteria by two independent evaluators precalibrated at 85% reliability. No failures were reported and α scores were recorded for all parameters. Statistical analysis was performed using a χ(2) test and the Fisher exact test (χ(2)=10.6; p=0.001). No teeth exhibited sensitivity in the three groups both at the two-week recall and two-year follow-up.