A new method for the radiological investigation of residual ridge resorption in the maxilla

Objectives: To develop a new method for assessing residual ridge resorption in the edentulous maxilla. Methods: Defined experimental and reference areas in the maxilla were drawn on transparent film laid over a panoramic radiograph and digitized. Bone a reas were measured with an integrated planimetry program and expressed as a ratio R. The effect of positioning errors on reliability of the method was investigated on dry skulls. The correlation between the change in ratio an d actual bone loss was examined by progressively reducing the height of an artificial residual ridge on one skull. Results: The coefficient of variation for the absolute ratio in different h ead positions was <0.05 and its correlation coefficient of the change in R and the degree of resorption was r(2) <greater than or equal to> 98.3%, P = 0.0001. Conclusions: Comparison of the experimental area with the reference area on serial panoramic radiographs appears suitable for the assessment of residu al resorption in the maxilla.