Laser-sintered Removable Partial Dentures (RPDs) Translation From Lab to Clinic

Objectives: Removable partial dentures (RPD) are traditionally made of casted alloys using the lost-wax technique. Laser-sintering is a new additive manufacturing technique that can produce three-dimensional metal objects quickly with high precision and at low cost. We have optimized the laser-sintering technique for processing RPD frameworks. However, in order to translate this technology into clinical practice, we need to characterize the biological and mechanical properties of the alloys, and the clinical performance of the RPDs. The objective of this study was to characterize the Co-Cr alloys prepared by laser-sintered and evaluate the clinical performance of RPDs processed by this new technology.
Methods: Co–Cr samples and RPDs were fabricated by either conventional casting (CC) or laser-sintering (LS). The mechanical, physical, and biocompatibility properties of the samples were analyzed in vitro. The clinical performance of the RPDs were evaluated in a pilot cross-over clinical trial in 8 patients. Each patient was randomly provided with one of the treatment options to try it for one month then replaced it with the other option for an additional one month. The patient satisfaction and prosthetic complications of the LS and CC RPDs were evaluated at 1, 2, and 4 weeks after denture delivery.
Results: LS Co-Cr showed higher rigidity, porosity, and fatigue resistance compared to CC alloy (p<0.05). Both materials had similar flexural strength, micro-hardness, and biocompatibility. Clinically, patients report significantly higher (p<0.05) levels of satisfaction with LS RPDs than with CC 4 weeks after delivery in terms of ease of cleaning, comfort, chewing food, and function of chewing white bread, sliced steak, and raw apples.
Conclusions: Both LS and CC alloys are biocompatible. Patients were more satisfied with LS RPDs than with CC RPDs, probably was because LS alloys are more precise and present better fatigue resistance than CC alloys.