Digital Versus Conventional Altered Cast Techniques For Constructing Mandibular Distal Extension Removable Partial Dentures Using Digitally Fabricated Frameworks: A clinical comparative parallel study of alveolar bone height changes

Background Conventional altered cast technique for distal extension removable partial dentures (RPDs) involve multiple clinical and laboratory steps. To overcome the limitations of conventional method and enhance bone support and load distribution, digital workflows have been introduced in RPD fabrication. Methods Twenty-two patients (n=22) of age ranging from 50 to 60 years were included in this parallel clinical study. Each patient received a maxillary complete denture and a mandibular bilateral distally extended RPD made with digitally constructed frameworks. Patients were randomly and equally divided into two groups (n=11) based on the altered cast method used: Group I : Digitally fabricated altered cast and Group II : Conventionally fabricated altered cast. Alveolar bone height changes of the residual ridge and around abutment teeth were assessed using CBCT at three intervals: 1 ^st 6 months (T1), 2 ^nd 6 months (T2) and 12 months (T3) post-insertion. Data were collected and statistically analyzed using SPSS software version 25. Results There was no statistically significant difference in bone resorption around abutment teeth in two groups at T1, T2 and T3 intervals after RPD insertion where ( P value= .837, .423, .550) respectively. There was no statistically significant difference in bone resorption of residual alveolar ridge in two groups at T1, T2 and T3 intervals after RPD insertion where ( P value= .850, .649, .949) respectively. Within each group the comparison of alveolar bone height changes around abutment teeth and of residual ridge revealed significant difference between time intervals. Conclusion Both digital and conventional altered cast techniques utilizing digitally constructed metal frameworks demonstrated comparable effectiveness of maintaining alveolar bone height of residual ridges and around abutment teeth of distally extended RPDs. Clinical trial registry number (No. NCT05899712) (06/09/ 2023)