Our objective was to determine the association between keratinized mucosa width and the health status of the supporting tissue around implants supporting overdentures. Sixty-six functioning dental implants were examined. Periodontal parameters measured included gingival index, plaque index, bleeding on probing, probing depth, mucosal recession, periodontal attachment level, radiographic bone level, and width of keratinized mucosa. A negative correlation was found between keratinized mucosa width and mucosal recession and periodontal attachment level. When data were dichotomized by keratinized mucosa width, the mean gingival index score, plaque index score, and bleeding on probing were significantly higher for those implants with a narrow zone (< 2 mm) of keratinized mucosa. A wider mucosal band (> or = 2 mm) was associated with less mucosal recession and periodontal attachment loss compared with a narrow (< 2 mm) band. The absence of adequate keratinized mucosa around implants supporting overdentures was associated with higher plaque accumulation, gingival inflammation, bleeding on probing, and mucosal recession.