The Therapeutic Gradient in Indirect Posterior Restorations: A Clinical Case Series

Introduction
The contemporary management of structurally compromised posterior teeth is guided by the principles of minimally invasive dentistry, emphasizing the preservation of healthy tooth structure while ensuring long-term functional and esthetic rehabilitation. The therapeutic gradient concept advocates selecting the least invasive indirect restoration according to the extent of tissue loss. This work aims to illustrate four clinical cases approached through four restorative modalities. It aimed to emphasize indications, preparation design, and limitations for each type.

Materials and Methods
Four clinical cases involving posterior teeth with increasing degrees of coronal destruction were managed using indirect adhesive restorations following the therapeutic gradient. Restoration selection was based on the amount of remaining tooth structure, cuspal involvement, and pulpal/endodontic status. The cases included one ceramic onlay for limited cuspal replacement, one veneerlay for moderate occlusal wear requiring partial cuspal coverage, one overlay for extensive coronal loss with complete cuspal coverage, and one endocrown for an endodontically treated tooth with severe coronal destruction. All restorations were fabricated from lithium disilicate ceramic using adhesive bonding protocols. Clinical procedures were standardized, and immediate clinical outcomes were assessed.

Results
All four restorations demonstrated excellent marginal adaptation, anatomical morphology, occlusal integration, and esthetic outcomes. The therapeutic gradient enabled individualized treatment planning by matching the restoration design to the severity of tissue loss, thereby maximizing tissue preservation while restoring function.

Conclusion:

The therapeutic gradient ensures appropriate indication and maximal preservation of tooth structure from onlay to endocrown. However, clinical success also depends on the adhesive procedure, particularly proper surface treatment, reliable bonding protocols, and strict isolation. Mastery of the bonding step is essential for achieving durable marginal integrity and long-term restoration performance.