Long-Term Stability of Soft and Hard Tissues After Guided Bone Regeneration in the Maxillary Anterior Region

This study examines the long-term condition of bone and gum tissues around dental implants in the upper front jaw after guided bone regeneration (GBR), a procedure used to rebuild bone at implant sites. Researchers review existing dental records and images obtained for clinical care and collect information during long-term follow-up. Enrollment has closed, and follow-up data collection is ongoing. Participants undergo intraoral scanning, oral and periodontal examinations, and questionnaires after providing written informed consent. The study assesses the volume and thickness of augmented hard tissues, bone levels around implants, and surrounding soft tissues. It also assesses implant and restoration survival, health around implants, complications, and patient-reported outcomes. Researchers will explore factors associated with long-term tissue stability. This is an observational study. It does not assign or change treatment. Cone-beam computed tomography (CBCT) images are used only when obtained for clinical reasons. No CBCT scan is performed solely for research purposes.

Inclusion Criteria: 1. Age 18 years or older. 2. Previous guided bone regeneration associated with single-tooth implant treatment in the anterior maxilla. 3. A single implant-supported fixed restoration; bridge restorations and multi-unit splinted restorations are not eligible. 4. Available clinical and radiographic records sufficient for analysis of the primary outcome. 5. Having reached, or expected to reach within the 3-year study period, the T5 long-term follow-up window, defined as approximately 5 years after GBR with an allowable variation of ±12 months. 6. Ability to complete intraoral scanning, oral examination, and questionnaires. 7. Ability to understand the study and provide written informed consent. Participants included only through retrospective data for whom consent cannot be obtained must meet the conditions for a waiver of informed consent approved by the ethics committee. 8. Stable periodontal condition and considered capable of completing long-term follow-up assessment by the investigator. Exclusion Criteria: 1. Inability to tolerate an oral examination or intraoral scanning. 2. Pregnancy or breastfeeding. 3. Smoking 10 or more cigarettes per day. 4. Severe systemic disease that may substantially affect bone metabolism or implant outcomes. 5. Immunodeficiency or HIV infection. 6. Uncontrolled active periodontitis or local inflammation. 7. Head and neck radiotherapy or chemotherapy within the previous year, or a history of intravenous bisphosphonate use. 8. Severe bruxism or clenching. 9. Poor oral hygiene or poor compliance. 10. Substantial missing information in historical GBR records that prevents determination of the surgical technique, grafting material, or imaging assessment time points. 11. Bridge restorations, multi-unit splinted restorations, or complex full-arch restorations that prevent independent evaluation of the individual implant. 12. Any other condition considered unsuitable for inclusion by the investigator.