Influence of the keratinized mucosa on peri-implant clinical parameters: A retrospective clinical study

OBJECTIVE: The purpose of the present clinical retrospective study was to evaluate the influence of the peri-implant keratinized mucosa (KM) on clinical parameters: mean plaque index, bleeding on probing, mean probing depth, and exposure of implant threads. MATERIAL AND METHODS: Patients were recruited during their routine maintenance visit from 2012 to 2014 and analyzed in two groups according to KM width around implants: wide keratinized mucosa width, i.e., ≥2 mm (WKM) and narrow keratinized mucosa width, i.e., <2 mm (NKM). The following clinical parameters were assessed: modified plaque index (mPI), probing depth (PD), bleeding on probing (BoP) and presence or absence of exposed implant threads (ET). T test, Mann-Whitney, and chi-square test were used for the statistical analysis. RESULTS: Third-eight patients with 200 implants were included. 178 implants were included in the WKM group and 22 in the NKM group. NKM group showed a higher mean percentage of sites with BOP (93,8%) than WKM group (87,5%) (p<0.05). There was no statistical difference between the 2 groups with respect to mPI, PD and ET. Smoking data was available for 37 patients: 5 smokers (13.5%) and 32 non-smokers (86.5%). The mean BoP for smokers was significantly higher than non-smokers (p <0.05). No statistical difference was verified between smokers and no smokers with respect to mPI, PD and ET. CONCLUSIONS: The presence of KM ≥ 2mm around dental implants was associated with lower bleeding on probing.