Clinical evaluation of direct cuspal coverage with posterior composite resin restorations

Composite resins have esthetic properties; they join the ability to preserve and reinforce sound tooth structure. Conservation is becoming popular for both small to medium defects and more compromised teeth.

This study aimed to evaluate the clinical performance of Class II cuspal coverage direct composite restorations.

Twenty patients, 18 years or older, were included in this clinical trial restoring 25 vital molar teeth with one or two missing cusps. Criteria for inclusion are two or three surface restorations, replacement of composite and amalgam fillings (secondary decay, fracture of either filling material or tooth structure, aesthetic considerations), or virgin teeth with decay undermining a cusp. Teeth with residual cavity walls less than 1 mm or with complete loss of the clinical crown were excluded. Teeth were restored using a combination of Ultra-Etch 35% phosphoric acid, PQ1 adhesive system, and Vit-l-escence microhybrid composite resin (Ultradent Products, Inc., South Jordan, UT, USA). The enamel peripheral skeleton of the restoration was built up first, followed by dentin and enamel occlusal surface stratification. Wedge-shaped increments of composite resin were placed and cured using the variable intensity polimerizer (VIP) light (Bisco Inc., Schaumburg, IL, USA) through a combination of a pulse and progressive curing technique.

All 25 restorations were evaluated at 6-month intervals during the 30-month period using a modified US Public Health Service (USPHS) criteria by two independent evaluators precalibrated at 85% reliability. No failures were reported and alpha scores were recorded for all parameters. Statistical analysis was performed using a Chi-square test (chi(2)) and the Fisher's exact test. Sixteen of the 25 samples (64%) exhibited preoperative sensitivity to air (chi(2)=10.6; p=0.001). A significant difference in tooth sensitivity was reported after completion of the restorations. No teeth exhibited sensitivity both at the 2-week recall and the 30-month follow-up (chi(2)=23.5; p < 0.0001).

Microhybrid composite resin demonstrated excellent clinical performance in direct cuspal coverage at completion of a 30-month evaluation. CLINICAL SIGNIFICANCE In selected clinical situations, cuspal coverage direct posterior composite restorations may represent a valid alternative to conventional indirect restorations.