12-months Clinical Evaluation of Fiber Reinforced Bulk Fill Resin Composite versus Incremental Packing of Nanohybrid Resin Composite in Restoration of Deep Proximal Lesions of Permanent Molars: A Randomized Controlled Trial.

Objective: The present clinical trial was conducted to evaluate the clinical performance of the biomimetic, bilayered structure utilizing a fiber reinforced bulk fill resin composite with a nanohybrid capping layer, compared to incremental packing of nanohybrid resin composite, in deep proximal cavities in permanent molars.

Material and methods: A total of 36 deep proximal cavities in vital molars were restored either with a bilayered structure of fiber reinforced composite resin as a dentine substitute and a capping layer of nanohybrid composite resin (n=18) or conventional, nanohybrid composite resin incrementation (n=18). The restorations were assessed over a period of 12 months using the modified USPHS criteria. The criteria evaluated were: fracture and retention, marginal integrity, marginal discoloration, anatomic form, proximal contact, surface texture, radiographic evaluation, postoperative sensitivity and secondary caries.

Results: There was no statistically or clinically significant difference between fiber-reinforced resin composite and conventional incremental resin composite. There was no risk for failure regarding all the evaluated modified USPHS criteria for both materials after 12 months (RR= 1(95% CI 0.0209 to 47.8503; P =1.0000)).

Conclusion: The biomimetic approach utilizing a fiber reinforced resin composite dentine substitute showed a comparable clinical performance to nanohybrid resin composite incrementation. Bulk fill fiber reinforced resin composite is an efficient alternative in restoration of deep proximal cavities in posterior teeth. Further long-term studies are necessary to confirm these results.