Occlusal onlays as a modern treatment concept for the reconstruction of severely worn occlusal surfaces

According to the Fifth German Oral Health Study, the caries experience in the German population is declining sharply. The number of teeth still present at an advanced age has also increased significantly in recent decades. This shows a clear trend towards long-term tooth preservation - possibly with fixed dental prostheses - which is further supported by the possibility to place implants to increase the number of abutments. The pronounced decline in caries experience has given Germany a leading international position in terms of dental health. But there is increasing evidence of risks associated with dental hard-tissue damage because of erosion/biocorrosion, attrition, and abrasion. The defect morphology of these wear-related lesions is different from that of caries lesions; occlusal surfaces are more often affected in the posterior region. Against this background, restorative treatment concepts have become significantly more differentiated in recent decades. Predominantly subtractive concepts to provide mechanical retention for the restoration using traditional cements are now replaced by less invasive, primarily defect-oriented procedures wherever feasible. In the case of pronounced dental hard-tissue loss, additive approaches also allow restorations that restore function. In addition, there are modifications of traditional procedures, such as defining the treatment goal in the lead-up to the treatment itself with the aid of a diagnostic wax-up. The wax-up provides orientation for the subsequent tooth preparation and allows a particularly economical approach to the removal of healthy dental hard tissue. Furthermore, the introduction of new preparation designs has contributed significantly to the preservation of dental hard tissue on the teeth to be restored. This article describes the principles of minimally invasive treatment using occlusal onlays for the reconstruction of severely worn occlusal surfaces. Keywords: adhesive technique, all-ceramic restorations, diagnostic wax-up, high-performance polymers, minimally invasive preparation, mock-up, occlusal onlays, occlusally oriented defect morphology, tabletops