A healthy relationship between dental restorations and the periodontium is of prime importance for the clinical longevity and esthetic harmony of full coverage restorations . One of the Most Common complications, derived from fixed prostheses is gingival recession, which constitutes an important clinical concern. This problem is largely associated with iatrogenic effects produced during dental preparation or as a result of poor prosthetic fit which can cause chronic inflammation leading to gingival margin recession around the restoration .
It has been demonstrated that a great amount of tooth structure is lost during the prosthetic preparations of abutments for full-coverage FDPs with tooth substance removal of 63% of 73%, this aggressive loss of tooth structure usually accompanied with pain and post-operative sensitivity. In comparison with the vertical preparation technique, there is less amount of tooth substance loss. this clinical study will provide benefits for practitioners and clinicians by guiding them to choose a more conservative treatment plan with the better marginal fit, clinical performance and satisfaction for the patients on the long term. rather than other benefits like less chair time, less risk for pulp injury, less time and cost