Comparison of the Chairside Time and Fitness of Michigan Splints Fabricated With Conventional Method and Digital Method: A Self-Controlled Study

Abstract

Purpose: To evaluate the chairside time and fitness of Michigan splints fabricated with conventional method and digital method. Material and Methods: Two Michigan splints were fabricated with conventional method and digital method respectively for 16 participants. In digital workflow, the data of dentitions were obtained by model scanning. Michigan splints were then designed, occlusal surface modified with the aid of fully adjustable virtual articulator, and fabricated by 3D printing technology with light-cured acrylic resin. In conventional workflow, splints were fabricated using waxed up method and fabricated with heat-cured acrylic resin. The chairside time of insertion and occlusal adjustment were recorded. The retention and comfort were evaluated by participants using 10cm Visual Analog Scales (VAS). Highly flowable Polyvinyl Siloxane (PVS) filled the space between tissue side of splints and occlusal surface of the natural dentitions. The fitness of the splints was calculated by scanning the tissue sides of splints with and without PVS replicas respectively. All data were divided into conventional group (control group) and digital group (test group), and self-controlled method was adopted. Differences between two groups were analyzed by paired t-test. Results: There was no statistical difference in insertion time between two groups (P=0.263). Test group took less chairside time for centric (605±436s vs. 945±427 s, P=0.007), protrusive (97.0±144s vs. 246±211s, P=0.036), and excursive (25.0±101s vs. 114±465s, P=0.026) occlusal adjustment than control group. The space of test group was significantly smaller than control group (350±120μm vs. 470±90.0μm, P<0.001). No statistical difference was detected in the scores of retention, comfort at postural position and comfort at centric occlusion between two groups (P≥0.113). Conclusion: Michigan splints fabricated with digital method need less chairside time and showed better fitness than conventional method.