Effect of Auxiliary Occlussal Devices on the Occlusal Accuracy of Multiple Implant-Supported Restorations Fabricated Using Digital Workflow: A Randomized Control Trial.

Objective: This study aimed to evaluate the effectiveness of auxiliary occlusal devices (AODs) in improving occlusal accuracy and reducing clinical adjustments in a fully digital workflow for multiple (3 or more) implant-supported single crowns.

Materials And Methods: Twenty-nine patients with a total of 106 implant-supported single crowns were enrolled. Participants were randomly assigned to either the test group (with AODs) or the control group (without AODs). Both groups underwent a digital workflow, and the morphology of restorations was recorded before and after occlusal adjustment using an intra-oral scanner. Quantitative occlusal modifications, including grinding and porcelain additions, were calculated by 3D analysis software, and crown remake (occlusal deficiency > 0.5 mm) was documented. Statistical analysis included the Mann-Whitney U test, Fisher's exact test, and generalized linear mixed model to assess the effects of group assignment, edentulous position, and their interaction on the amount of occlusal adjustment.

Results: The test group exhibited significantly lower rates of porcelain addition (16.4% vs. 26.3%, p = 0.051) and crown remake (3.8% vs. 20.4%, p = 0.015) compared to the control group. The absolute amount of occlusal modification was significantly reduced in the AOD group (median 0.3290 mm) compared to the control (median 0.5273 mm, p = 0.001). Notably, free-end saddle crowns showed a higher incidence of occlusal porcelain addition (p = 0.022), but the use of AODs in these cases significantly mitigated the need for adjustments (p = 0.007).

Conclusion: The incorporation of AODs in a digital workflow significantly improves the precision of occlusal registration and reduces chairside modifications and remakes. AODs are especially beneficial in complex cases such as free-end saddles and should be considered a valuable adjunct in digital implant prosthodontics.

Trial Registration: This study was registered on the Chinese Clinical Trial Registry (https://www.chictr.org.cn/; ChiCTR2200064819).