{'fraction_non_alphanumeric': 0.03218645948945616, 'fraction_numerical': 0.022197558268590455, 'mean_word_length': 5.195876288659794, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
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.