Influence of crown-lengthening surgery on teeth rehabilitated with ceramic single crowns: A 12-month prospective clinical study.

OBJECTIVE: To compare the clinical periodontal parameters of teeth restored with a single ceramic crown, with and without crown lengthening procedure. METHODS: This prospective, longitudinal, controlled, and single-blinded clinical trial involved 22 patients with a total of forty-one teeth with ceramic crowns. The teeth were divided into two groups: test (n = 21), comprising teeth rehabilitated post crown-lengthening surgery, and control (n = 20), comprising teeth rehabilitated without crown-lengthening surgery. Plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing (BoP), and clinical attachment level (CAL) were compared between groups (surgically treated and non-surgically treated) and within each group for each type of site (treated -tt; adjacent - ad; and nonadjacent - nad). Additionally, gingival phenotype (GP), gingival recession (GR), and keratinized tissue width (KTW) were also assessed post- restoration. Statistical analyses used a significance level set at 5 %. RESULTS: PI, GI, and BoP were reduced, but no statistically significant differences were observed within each group or between groups for most follow-up periods. CAL of the TT sites was consistently higher in the test group, and PD was also higher in the test group (p < 0.05), except at T3. adPD, nadPD, adCAL, and nadCAL demonstrated no significant differences between groups and periods. A significant association was identified between GP and the occurrence of GR, with the thick-flat phenotype demonstrating less association with GR, regardless of whether crown lengthening was performed or not. CONCLUSION: Crown-lengthening surgery in rehabilitated teeth does not significantly affect PI and GI after 12 months. Although crown-lengthening surgery affected PD and CAL in TT sites, it did not affect adjacent and non-adjacent sites. CLINICAL RELEVANCE: These findings emphasize the importance of considering individual patient factors and the potential impact on periodontal tissues when planning crown-lengthening surgery. Clinicians must have a comprehensive understanding of the dynamics of the periodontal tissues involved in restorative treatments to optimize the procedure, increase success rates, and minimize potential complications.

Assessment of gingival phenotype through periodontal and crown characteristics: a cluster analysis.

OBJECTIVE: To evaluate gingival phenotypes in 100 subjects (n = 100), with regard to maxillary central incisors and surrounding periodontium in an observational diagnostic study. MATERIALS AND METHODS: Individuals were grouped based on: Probing depth (PD); keratinized mucosa (KM); Ratio Height/Width Crown (CH/CW), papilla area (PA), gingival thickness (GT) and Gingival Volume (GV). ANOVA and chi-square tests were performed with a significance level of 5%. Results: PD (p=0.860) and CH/CW (p=0.086) were not statistically significant. Cluster analysis identified three groups: Cluster I (n = 32) had the lowest values: KM (4.54mm), GT (0.83mm), PA (15.64mm²) and GV (3.80mm³); Cluster II (n = 43) presented KM (8.02mm); GT (1.40mm); GV (11.18mm³) and PA (14.10mm²); Cluster III (n = 19) exhibited an average KM of 5.57mm, GT (1.14mm), PA (20.08mm²) and GV (6.48mm³). RESULTS: Cluster I was characterized as a thin phenotype; cluster II as thick, and cluster III, as an intermediate. Significant associations were found when transparency on probing was compared among clusters (p less than 0.05) and gingival exposure when smiling (p less than 0.05). CONCLUSION: Thin phenotype was found in 34.04% of the sample (cluster I), thick phenotype in 45.75% (cluster II) and intermediate phenotype in 20.21% (Cluster III)..