关键词: 数字印模, CBCT, 游离端可摘局部义齿

Abstract: [Abstract] Objective To investigate the application of digital analog pressure model in the fabrication of free end removable partial dentures. Methods Two different methods were used to make dentures for 21 subjects . In the experimental group, the soft and hard oral tissue morphology and occlusal relationship of the patients were scanned with 3SHAPE oral digital impression instrument, and the digital model was generated, which was imported into the denture design software together with the CBCT data of the patients. CBCT images and digital model images were fitted and aligned according to the position of remaining teeth to obtain the information of bone morphology and corresponding mucosal thickness. Virtual grinding or buffering operation was carried out on the digital model to generate the analog pressure digital model on which the dental prosthesis framework was designed.the framework was 3D printed and the prosthesis was completed through tooth arrangement and glue filling. In the control group, pressure impression model was obtained by model replacement technique to complete the denture fabrication. The clinical effect of two groups of dentures was compared by testing. The morphological differences of mucosa at 63 sites on the free end of the working model obtained by the two methods were measured and analyzed. Results Among 21 subjects, the proportion of mucosal tenderness in the experimental group was 4.76% significantly lower than that in the control group, 23.81%. The mucosal differences of 63 sites between the simulated pressure digital model and the pressure impression model were analyzed. There was no significant difference between the experimental group and the control group in soft tissue deformation of alveolar crest near abutment（P=0.11）; The soft tissue deformation of distal abutment teeth in the experimental group was significantly greater than that in the control group(P＜0.05)；In the mandibular protuberance area, the experimental group had more buffer space than the control group, and there was a significant difference in morphology(P＜0.05). Conclusion The digital impression was fitted with CBCT data for personalized digital model modification, which can selectively adjust the mucosal pressure distribution and effectively relieve the uneven subsidence and tenderness of the free end of the removable partial denture. The clinical effect was satisfactory.

Key words: digital impression, CBCT, free end removable partial denture