Evaluation of Peri-implant Tissue Health Status Affected by Keratinized Mucosa

Objectives: It has been discussed whether the presence of keratinized mucosa is required to maintain peri-implant tissue health. Although many studies have been conducted in order to provide scientific evidences for this important issue, the consensus is not provided yet. Peri-implant tissue health status were related to various factors such as the degree of patients’ oral hygiene and a history of periodontitis, but most studies did not provide the definite information. This cross-sectional study was performed to determine whether an association exists between the presence of keratinized mucosa (≧2mm) and peri-implant tissue health status using a multivariate analysis.
Methods: A total of 279 dental implants were placed in 95 partially edentulous patients (30 males, 65 females), and subsequently restored with fixed prostheses. They were recalled and checked up more than one year after finishing prosthodontic treatment. Clinical parameters measured at the time included modified plaque index (mPI), modified bleeding index (mBI), probing pocket depth (PPD) and radiographic bone loss (BL). The effects of the following potentially explanatory variables on these parameters were analyzed: the presence of keratinized mucosa, age, sex, oral hygiene status, history of periodontitis, cigarette smoking, implant cite, and elapsed time since prosthesis delivery. Statistical analysis included multivariate ordinal logistic regression and generalized estimating equations. Significance was established when P was less than 0.05.
Results: The mPI, mBI, and PPD in the presence or absence of the keratinized mucosa did not show statistically significant differences. However, the presence of keratinized mucosa was significantly related to BL (p = 0.034).
Conclusions: The results of the present study suggest that the presence of keratinized mucosa is useful for restraint of the bone resorption and is necessary for maintaining peri-implant tissue health.