This retrospective study investigated the changes in the maxillary sinus floor and alveolar crest following extraction of maxillary molars. Pre- and postextraction cone beam computed tomography scans of 23 patients were analyzed. Paired-sample t tests compared pre- and postextraction measurements, and independent-sample t tests were utilized for intergroup comparisons. Pearson correlation was used to assess the association between the measured variables and the outcome measures. The mean alveolar bone height reduction was 3.42 ± 2.40 mm and the alveolar crest loss was 3.07 ± 2.53 mm. The maxillary sinus floor position shifted coronally by a mean of 0.47 ± 0.32 mm. Approximately 88% of postextraction changes in alveolar bone height were due to alveolar crest changes, compared to 12% due to changes in the sinus floor position. The results of this study challenge the commonly held concept of extensive postextraction maxillary sinus floor alterations leading to sinus pneumatization.
