The purpose of this study was to demonstrate the feasibility of applying cone-beam computed tomography（CBCT） to observe dimensional changes in human alveolar bone continuously after tooth extraction.Sixty patients were selected from a CBCT database.Each patient had two CBCT scans（CBCT I and CBCT II）,one taken before and one taken after implant surgery.A fixed anatomic reference point was used to orient the horizontal slice of the two scans.The alveolar ridge width was measured on the horizontal slice.In each series of CBCT I sagittal slices,the number of slices from the start point to the pulp center of the test tooth was recorded.The tooth length was measured on the sagittal slice.In each series of CBCT II slices,tooth length was measured on a sagittal slice selected based on the number of slices from the start point to the pulp center recorded in CBCT I.Intraobserver reliability,assessed by the intraclass correlation coefficient（ICC）,was high.Paired sample t-tests of repeated measurements of both tooth length and alveolar bone width showed no statistically significant differences（P0.05）.This study has proved that projection differences among CBCT scans taken at different time points from one patient can be neglected without affecting the accuracy of millimeter scale measurements.CBCT is a reliable imaging tool for continuously observing dimensional changes in human alveolar bone.
