The effect of keratinized mucosa width on peri-implant outcome under supportive postimplant therapy.

BACKGROUND: Long-ranging data on the influence of keratinized mucosa (KM) on peri-implant tissue status have been scarce. PURPOSE: Retrospective evaluation of peri-implant diseases and KM width in patients with versus without mucogingival surgery. MATERIALS AND METHODS: Under supportive postimplant therapy (SIT) in a private practice, 68 patients with peri-implant KM widths <1 mm were identified between 1992 and 2011 (eight dropouts). Thirty patients rejected surgery (control [C] group), and 30 patients agreed (intervention [I] group). After at least 1 year, KM width, mucositis, and peri-implant conditions were assessed. RESULTS: Sixty nonsmoking patients (n = 105 implants) were available for assessment after 12.10 +/- 4.93 years. No implants were lost (survival rate: 100%). An average of 10.69 years after surgery, the I group implants showed a mean KM gain of 3.10 +/- 1.43 mm (C group: 0 mm). The mucositis rates were as follows: I group: 38.98%; C group: 31.91%. Peri-implantitis was detected in two implants (1.87%) and two individuals (6.67%) in the I group. No significant differences between groups were found, except that the KM width values were significantly greater in the I group (p < 0.001). CONCLUSIONS: Low incidences of peri-implant diseases over long periods can be expected in patients attending SIT programs, independent of the absence or presence of KM.