Influence of gingival phenotype on crestal bone loss at implants : A long-term 2 to 20-year cohort study in periodontally compromised patient.

Purpose: The aim of this long-term cohort study in periodontally compromised patients with implants was to analyze the correlation between gingival phenotype and peri-implant crestal bone loss, and between clinical measures and gingival phenotype.

Methods: Implant-supported single crowns and bridges were used to rehabilitate 162 implants in 57 patients. Patients were examined over a 2 to 20-year period on a recall schedule of 3 to 6 months. In addition to recording clinical parameters, intraoral radiographs were taken at baseline (immediately after superstructure insertion) and at 1, 3, 5, 10, 15, and 20 years. Patients were differentiated into phenotype 1 with thin, scalloped gingiva and narrow attached gingiva (n = 19), phenotype 2 with thick, flat gingiva and wide attached gingiva (n = 23), or phenotyp 3 with thick, scalloped gingiva and narrow attached gingiva (n = 15).

Results: The mean peri-implant crestal bone loss during the first 12 months was 1.3 ± 0.7 mm. Patients with gingival phenotype 1 had a significantly greater rate of increased crestal bone loss at implants (p = 0.016). No significant differences were present in subsequent years. The prevalence of mucositis at all implants was 27.2%, and the prevalence of peri-implantitis 9.3%. Univariate analyses indicated a significantly higher peri-implantitis risk in patients with gingival phenotype 2 (p-OR = 0.001; p-OR = 0.020). The implants of patients with phenotype 2 had significantly greater probing depths (1st year p < 0.001; 3rd year p = 0.016; 10th year p = 0.027; 15th year p < 0.001). Patients with gingival phenotype 3 showed no significantly increased probing depths, signs of inflammation and crestal bone loss.

Conclusions: Patients with a gingival phenotype 1 have greater crestal bone loss at implants during the first year of functional loading. Patients with gingival phenotype 2 had significantly greater probing depth at implants and risk of peri-implantitis.