Clinical performance of different types of posterior bulk-fill resin composite restorations in permanent teeth: a systematic review

Bulk-fill resin composites were developed to overcome limitations of incremental placement techniques: time consumption and air bubble entrapment. They are available in different viscosities, including high-viscosity (sculptable) and low-viscosity (flowable). Furthermore, practitioners deploy various techniques, such as sonic activation and preheating, to reduce the viscosity of bulk-fill resin composites. However, few studies have evaluated the clinical performance of different bulk-fill resin composite types. Consequently, this systematic review aimed to evaluate and compare the clinical performance of sonic-activated, preheated, and flowable bulk-fill resin composites versus conventional high-viscosity bulk-fill materials in permanent posterior teeth, regarding the following parameters: functional (retention, marginal adaptation, and anatomic form), esthetic (marginal discoloration, color match, and surface texture), and biological parameters (secondary caries and postoperative sensitivity).