The changes in crestal bone height observed in standardized radiographs of porous-coated dental implants after 3 to 4 years of function in the support of mandibular overdentures is reported for a group of 48 completely edentulous patients. Possible correlations between bone height and each of probing attachment level, Plaque Index, and Sulcular Bleeding Index were investigated. Mean bone loss values were determined to be 0.43 mm in year 1, decreasing to 0.17 mm and 0.13 mm in years 2 and 3, respectively. During year 4, there was an apparent mean gain of 0.05 mm. While the mean mucosal tissue thickness (1.3 mm) was similar to that reported by other investigators, it was not possible to show a correlation between bone height and probing attachment level. Likewise, correlations between bone height and Plaque Index or between bone height and Sulcular Bleeding Index could not be demonstrated. Keywords: crestal bone height, Plaque Index, probing attachment level, Sulcular Bleeding Index