Abstract: Objective: To access the deformation of mandibular distal-extension mucosa with altered-cast impression techniques. Methods: Seven patients receiving a mandibular distal-extension removable denture with the altered-cast impression in prosthodontics department of Beijing Stomatological Hospital were assigned. Mandibular CBCT was performed and digital intraoral scanner was used to acquire anatomic impression of mandible. The altered cast was digitalized by the laboratory scanner. The digital models were registered by Geomagic software. The thickness and the deformation of distal-extension mandibular mucosa were processed and analyzed with Geomagic and R language softwares. Results: The thickness of distal-extension mucosa was (2.21±0.72) mm. The deformation of distal-extension mucosa was (0.38±0.55) mm, which increased from mesial to distal. There was no significant correlation between the mucosal deformation and the thickness in each point. Conclusion: The deformation of distal-extension mucosa increased from mesial to distal. There was no significant correlation between the mucosal deformation and the thickness in each point.

Key words: digital analysis, altered cast impression, deformation of mucosa