Corresponding Author

Aisha Zakaria Mostafa

Article Type

Original Article




Objective: This study was conducted to assess the abutment teeth for digitally constructed clasp-retained and attachment-retained removable partial dentures (RPD) in cases with a class I partially edentulous mandible. Material and methods: In this clinical trial, throughout six years, 10 patients each received two mandibular class I RPDs that were created using computer-aided design and computer-aided manufacturing (CAD-CAM) over six years. The first one was clasp retained RPD (Group1) for 3 years then extra-coronal attachment with cantilever retained RPD for an additional 3 years (Group 2). The abutment's clinical parameters (pocket depth, bleeding index, and plaque index) and alveolar bone level changes were assessed. Result: In Group 1, statistically less bone resorption after 1 year at the mesial side (0.19±0.08), at the distal side (0.61±0.11), compared to Group 2 at mesial (0.26 ±0.07), at distal (0.91 ±0.21) where P value M=0.048, D=0.010. The same result was after 3 years of follow-up P value M=0.008 D=0.004. By the end of each treatment option, there was a statistically significant increase in the abutment alveolar bone resorption, which was accentuated at the distal sides. There were no statistically significant differences between the two treatment options when comparing the clinical parameters of the abutment. By the end of both treatments, the bleeding index, the plaque index, and the probing depth had significantly increased. On the other hand, Group 2 had significantly less abutment mobility compared to Group 1 where P value< 0.001. While the abutment mobility in Group 2 remained the same and significantly increased over time in Group 1. Conclusions: The abutment teeth's alveolar bone is preserved in the clasp retained CAD/CAM constructed RPD while the attachment retained CAD/CAM constructed RPD prevents abutment teeth mobility. Although the clinical parameters tested with the clasp retained RPD better, there was no statistically significant difference when RPD was retained with the attachment. Over time for both treatment groups clinical parameters and bone resorption significantly increased


CAD\CAM, RPD, extra-coronal attachment.