Prosthodontics

This crossover clinical study aims to evaluate the influence of three different intraoral scanning techniques on the scanning accuracy and passive fit of mandibular implant-supported fixed detachable prostheses in completely edentulous patients. Each participant will undergo digital implant scanning using three methods: splinted scan bodies, horizontal non-calibrated scan bodies (IO Connect), and auxiliary geometric devices.

This randomized crossover clinical trial aims to evaluate the effect of different three-dimensional (3D) printing orientations and layer thicknesses on the trueness, dimensional accuracy, and patient satisfaction of maxillary complete dentures in completely edentulous patients. Each participant will receive two maxillary 3D-printed complete dentures fabricated using the same printing orientation (0°, 45°, or 90°) with two different layer thicknesses (50 μm and 100 μm) in a crossover sequence. The study will compare the influence of these printing parameters on denture accuracy and patient-reported outcomes to identify the optimal 3D printing settings for complete denture fabrication.

This clinical trial aims to compare three different impression techniques used to fabricate full-arch implant-supported dental prostheses. Accurate impressions are essential to ensure a passive and precise fit of the final prosthetic framework, which contributes to long-term implant success and patient comfort. In this crossover study, participants with four osseointegrated dental implants in the lower jaw will undergo three types of impressions: Conventional splinted impression using polyvinyl siloxane (PVS) material. Standard digital impression using an intraoral scanner. Geometric pattern-assisted digital impression, which incorporates a visual reference pattern to improve scan alignment and accuracy. Each participant will receive all three impression techniques in a randomized sequence, at different time points. The accuracy of each method will be assessed by evaluating the passivity of the resulting prosthetic frameworks using two methods: (1) digital superimposition analysis to measure three-dimensional (3D) spatial deviation, and (2) the clinical "one-screw test" to detect misfit. The study seeks to determine whether digital scanning, particularly with geometric pattern assistance, can provide accuracy comparable to or better than conventional methods. Findings may guide improvements in digital prosthodontic workflows and support more efficient, predictable treatment outcomes.