Lifespan of restorations in stress-bearing posterior cavities relies on various factors, including the materials, the dentist, and the patient. According to the dental literature, annual failure rates of posterior composite resin inlays and onlays range from 0% to 10%, demonstrating that indirect posterior restorations are a long-lasting option for the rehabilitation of major defects. The literature was searched in the most well-known databases, Medline and Embase, for all pertinent research published up to the middle of 2022. Within the constraints of this in vitro study, the results demonstrated that the use of composite resin overlays represents a conservative approach to endodontically treated tooth rehabilitation. All composite resin overlays had fracture strengths greater than the expected bite forces. The introduction of glass fibers boosted fracture resistance and had a beneficial influence on failure mode and thus re-restorability in the event of fracture.