Prospective Clinical Study of Zirconia Full-coverage Restorations on Teeth Prepared With Biologically Oriented Preparation Technique on Gingival Health: Results After Two-year Follow-up

Objectives: To evaluate the clinical behavior of one-piece complete-coverage crowns and fixed partial dentures (FPDs) on teeth with vertical preparation without finish line biologically oriented preparation technique (BOPT). Methods and Materials: This prospective study included 52 patients requiring treatment with restorations in the esthetic region: 74 crowns and 27 FPDs. The sample included a total of 149 teeth that were prepared vertically without finish line. The sample was divided into two groups: one-piece crowns and FPDs, all with zirconia cores, feldspathic ceramic veneer, and a 0.5-mm prosthetic finish line of zirconia. All procedures were carried out at the University of Valencia from 2013 to 2014. The following parameters were evaluated over a two-year follow-up: oral hygiene, periodontal state, gingival thickening, gingival margin stability, the presence of complications, and restoration survival rate. Patient satisfaction with treatment was assessed by means of a visual analogue scale (VAS). Results: Two years after treatment, 80.5% of treated teeth remained free of gingival inflammation and bleeding. Mean gingival thickening was 0.41 +/- 0.28 mm for one-piece crowns and 0.38 +/- 0.36 mm for FPDs. Gingival margin stability was 100%, but 2% of the sample presented biological complications. The VAS patient satisfaction scores were eight out of a maximum score of 10. Conclusions: Two years after treatment, vertical preparation without finish line produces gingival thickening, margin stability, and optimal esthetics. Neither crowns nor FPDs presented any mechanical complications.