Purpose: To evaluate the clinical performance of direct Class II fiber-reinforced composite restorations on nonvital teeth. Materials and Methods: Thirty patients age 18 or older were included in this clinical trial restoring 35 molars. The inclusion criteria were: two- to four-surface restorations, replacement of composite and amalgam restorations necessary or unrestored teeth with decay reaching the pulp, teeth having homogeneous root canal fillings terminating 0 to 2 mm from the radiographic apex. 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. The enamel peripheral shell of the restoration was built up first; a resin-impregnated piece of polyethylene ribbon fiber (Ribbond Triaxial) was covered with B1 Perma-Flo flowable composite, placed into a prepared canal, folded, and light cured; then, dentin and enamel occlusal surface stratification was completed. All 35 restorations were evaluated at 6 months and 1 year by two independent evaluators using modified USPHS criteria. Results: No failure was reported and alpha scores were recorded for all parameters. Before starting the treatment, 26 out of 35 teeth (74%) had apical periodontitis as diagnosed radiographically. At the 1-year recall, no signs of periapical lesions were detected and radiographs reported neither periodontal ligament widening nor periapical radiolucency. Conclusion: Direct fiber-reinforced composite resin restorations demonstrated excellent clinical performance at 1 year.

Keywords: adhesive system, composite resin, Class II restoration, nonvital teeth, post and core, UHMWPE fiber, clinical report