Retention, Stability, and Accuracy Of 3D Printed Reduction Guides for Removable Partial Dentures

This study aimed to compare the accuracy of reduction guides produced through virtual planning and three-dimensional (3D) printing with those produced conventionally.

Definitive casts of partially edentulous arches were used to fabricate reduction guides [Conventional Group (CG=30); Digital Group (DG=30)]. The guides were designed for anterior and posterior teeth with adjacent contacts and isolated posterior abutments. Retention, stability, accuracy of the guiding planes, and time required for each step were recorded. Sensitivity and specificity tests were performed to assess accuracy. Fisher's Exact test was used to evaluate associations between variables, and the Mann-Whitney test was applied for time comparisons.

Both techniques achieved 100% retention and stability for guides placed on anterior and posterior teeth with adjacent contacts. For isolated teeth, retention ranged from 70% to 90% and stability from 60% to 70%, with no significant differences between techniques (P>.05). Accuracy ranged from 0.80 (anterior teeth) to 1.00 (posterior teeth). There was higher precision for guides fabricated on molars (100%) and isolated abutments regardless of the surface analyzed (76%-100%). The digital technique required significantly more time for design, guide fabrication, and overall processing (P<.001), however, isolated abutments were more time-efficient (P<.001).

The digital technique demonstrated comparable accuracy, retention, and stability to the conventional method. Despite longer processing time, it offers standardization and reduced chairside time.