Evaluation of Implant Abutment-Level Digitalization Techniques

Evaluation of Implant Abutment Level Digitalization Techniques: A Clinical Methodological Study

This methodological clinical study aims to evaluate digital workflows used for the intraoral digitalization of cement-retained implant abutments in situations where implant impression components are unavailable and abutment replacement is not feasible. Three digital impression workflows were compared through quantitative analysis of three-dimensional implant positions derived from digital datasets obtained using scan bodies and abutment-level scans. Implant positions were defined by virtual implant axes and analyzed using reverse engineering software. The study evaluates whether combined intraoral-extraoral abutment scanning provides comparable accuracy to direct intraoral abutment scanning.

Digital workflows have increasingly been integrated into implant prosthodontics through the use of intraoral scanners and CAD-CAM technologies. While scan bodies are considered the gold standard for transferring implant position digitally, clinical situations may arise in which implant impression components are unavailable or replacement of the existing abutment is not feasible. In such scenarios, direct intraoral digitalization of the existing implant abutment has been proposed as an alternative method for capturing implant position during prosthetic maintenance or restoration replacement. However, the accuracy and clinical reliability of abutment-level digitalization remain uncertain.

The aim of this methodological clinical study is to compare different digital workflows for the intraoral digitalization of cement-retained implant abutments in clinical conditions where conventional implant impression components cannot be used. Three digital impression workflows were evaluated by comparing three-dimensional implant positions obtained from digital datasets. Implant positions were defined by virtual implant axes derived from scan body data and abutment-level scans, and analyzed using reverse engineering software.

Inclusion Criteria:

1. Voluntary participation in the study after reading and signing the informed consent form 2. Adult patient over the age of 18 who has completed growth and development 3. Having healthy dental and periodontal conditions 4. Presence of partial edentulism in the functional region requiring two-implant-supported restorations with two or three occlusal units 5. Having a fixed dentition in the arch with edentulism 6. Having a fixed dentition in the opposing arch 7. No need for vertical or horizontal prosthetic correction in the interarch occlusal relationship 8. Presence of bone-level implants placed with "straightforward" surgical approach (as defined by the SAC classification system [195]), without advanced surgical techniques

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Exclusion Criteria:

1. Refusal to participate voluntarily in the study after reading the informed consent form 2. Presence of any absolute contraindication to implant treatment (e.g., history of radiation therapy, bone cancer, metabolic disorders) 3. Presence of systemic risk factors for implant treatment (e.g., steroid therapy, uncontrolled diabetes, immunological disorders, pregnancy) 4. Presence of local risk factors for implant treatment (e.g., periodontal disease, bruxism, poor oral hygiene) 5. Presence of temporomandibular joint disorders that limit jaw movements

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