The management of structurally compromised posterior teeth remains a common yet challenging aspect of restorative dentistry. Determining whether weakened cusps should be preserved or reduced is critical to the long-term success of direct restorations. 

This lecture explores a practical decision-making framework for evaluating cuspal integrity and selecting the most appropriate direct restorative approach. Through a series of clinical cases, the presentation will illustrate when cusps should be maintained and reinforced (“Cusp ON”) and when cuspal reduction and coverage (“Cusp OFF”) is the more predictable option. 

By the end of the lecture, clinicians will gain practical protocols for managing posterior teeth with significant structural loss while maximising longevity, predictability, and aesthetic outcomes.