This randomized crossover clinical trial compares the passivity of fit of complete-arch mandibular implant-supported frameworks fabricated using three impression techniques: a non-calibrated splinted digital scan body system (IO-Connect), a Reverse Scan Body (RSB) digital impression technique, and a conventional splinted open-tray impression technique. Eight completely edentulous patients each receiving four mandibular implants will be included. Passivity of fit will be evaluated clinically using the Sheffield one-screw test and radiographically using intraoral periapical radiographs obtained with the parallel technique.
Full-arch implant-supported fixed prostheses require a high degree of passive fit to avoid mechanical and biological complications. While digital impression workflows are increasingly used as alternatives to conventional splinted impressions, evidence directly comparing their clinical accuracy for complete-arch implant frameworks remains limited, particularly for the IO-Connect non-calibrated splinting system and the Reverse Scan Body technique. Eight completely edentulous patients with at least four mandibular implants will be enrolled. Using a crossover design, each patient will undergo all three impression techniques: Group I (IO-Connect splinted scan bodies), Group II (Reverse Scan Body technique), and Group III (conventional splinted open-tray impression with polyvinyl siloxane and Type IV stone casts). For each technique, a corresponding implant-supported framework will be fabricated and evaluated for passivity of fit using the Sheffield one-screw test and periapical radiographs taken with a paralleling device to assess microgaps at the implant-framework interface.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
8
Digital impression of the mandibular arch obtained using IO-Connect non-calibrated splinted scan bodies to fabricate the implant-supported framework for Group I.
Digital impression obtained using the Reverse Scan Body (RSB) technique, involving extraoral scanning of scan bodies and superimposition with intraoral tissue scans, to fabricate the implant-supported framework for Group II.
Conventional splinted open-tray impression using polyvinyl siloxane material and Type IV dental stone to fabricate the implant-supported framework for Group III.
Faculty of Dentistry, Mansoura University
Al Mansurah, Dakahlia Governorate, Egypt
RECRUITINGPassive Fit Assessed by Sheffield One-Screw Test
The framework was seated on all implants and a single distal screw was fully tightened; remaining screw sites were examined visually and tactilely for lifting, rocking, or gaps as an indicator of passive fit.
Time frame: The evaluation of passive fit by Sheffield one-screw test will be done 3 months after implant placement (3M-IP), at framework try-in for each of the three impression techniques.
Passive Fit Assessed by Periapical Radiographs
Intraoral periapical radiographs were obtained at each implant site using a paralleling device and evaluated for microgaps at the implant-framework interface.
Time frame: The evaluation of passive fit by periapical radiographs will be done 3 months after implant placement, at framework try-in for each of the three impression techniques.
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