The influence of peri-implant keratinized mucosa on brushing discomfort and peri-implant tissue health

Objective: The aim of this study was to compare the level of brushing discomfort (BD) during oral hygiene and peri-implant clinical variables between patients presenting implant sites with a band >= 2 mm and <2 mm of keratinized mucosa (KM). Materials and Methods: Participating patients were recruited during routine maintenance followup visits from January to October 2013. Based on the presence of KM, patients were allocated into two groups: implant sites with >= 2 mm of KM (Wide Group): and implant sites with <2 mm of KM (Narrow Group). Patients were clinically assessed, and plaque index (PI), probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP) data were collected from three sites at the buccal aspect of each implant. Subsequently, patients received standardized oral hygiene instructions and cleaning devices and were asked to clean around the experimental implant sites. All patients reported on the level of BD using the visual analog scale (VAS). Non-paired Student's t-test, Wilcoxon's signed-rank test, and chi-square tests were performed to analyze the outcome variables (P < 0.05). Results: Eighty patients with a total of 270 implant sites were included. Implant sites in the Narrow Group exhibited higher levels of BD (P < 0.001), PI (P = 0.0021), and BoP (P = 0.017) than implant sites in the Wide Group. Conclusion: Implant sites with a band of <2 mm of KM were shown to be more prone to brushing discomfort, plaque accumulation, and peri-implant soft tissue inflammation when compared to implant sites with >= 2 mm of KM.