To evaluate the absorption of alveolar bone in anatomic impression and functional impression technique in the repairment of Kennedy class Ⅱ denture defect by cone beam CT(CBCT).

16 patients with mandibular Kennedy Class Ⅱ denture defect were randomly divided into the function group and the anatomical group (n = 8). The function group adopted the functional impression, the anatomical group used anatomic denture impression for denture making. Before denture wearing and after 6 months of normal use of denture, CBCT were used to measure the height of residual alveolar bone in the mesial and distal alveolar bone, and the height difference between the anterior and posterior teeth.

After 6 months of denture wearing, the height difference of the mesial (n = 0.742, P < 0.05) and distal (t = 5.727, P < 0.05) of the terminal abutment alveolar bone in anatomical group is significantly higher than that of the function group (P < 0.05); the height of residual alveolar bone of anatomical group and functional group has no significant difference (P > 0.05).

The denture made by function impression can reduce the absorption of alveolar bone in the mesial and distal of terminal abutment teeth, while different impression methods don’t have obvious influence on the absorption of residual alveolar bone during the short observation research term.