Dental Prosthesis, Implant-Supported

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 research is being done to evaluate the clinical, technical, biological, and aesthetic results of two different fabrication methods (additive and subtractive) for creating implant-supported fixed dental prostheses (iFDPs). Patients will receive an iFDP, meaning an implant-supported crown, according to regular treatment protocols. The fabrication method used to create the implant-supported crown will be decided in a randomised way. Clinical and radiological examinations will be performed prior to and when receiving the implant-supported crown and during a follow-up period of 3 years. Furthermore, technician- and patient-reported outcomes will be evaluated used questionnaires.

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.