An assessment of the accuracy of ridge-mapping in planning implant therapy for the anterior maxilla

The use of ridge-mapping to assess bone levels available for implant placement in the anterior maxilla avoids some of the problems associated with CT scanning. The aim of this study was to assess the accuracy of ridge-mapping callipers in determining bony ridge widths in the anterior maxilla prior to dental implant surgery. A modified surgical stent was designed to locate the beaks of ridge-mapping callipers at the same points on the jaw before and after mucoperiosteal flap reflection. Eleven subjects were included in the study. Measurements (n=100) were made at 25 implant sites, 50 "pre-operative" and 50 "intra-operative" at 3 mm and 6 mm distances from the crest of the ridge. There were statistically significant (P<0.0001) differences between pre- and intra-operative measurements. Based on pre-operative measurements, clinical judgements were made as to whether supplementary procedures such as guided bone regeneration would be required. Unanticipated supplementary procedures were required at 10 fixture sites. The findings indicate that ridge-mapping alone is insufficient to accurately predict bone available for implantation in the anterior maxilla. It is suggested that ridge-mapping may provide reliable information about bone levels when the labial aspect of the anterior ridge is not markedly concave.