Guided Bone Regeneration (GBR) is a widely used technique during dental implant surgery to help rebuild bone around the implant and improve its long-term appearance and stability. This study investigates whether the amount of bone that regrows depends on a person's original bone shape, known as the Individual Phenotypical Dimension (IPD). The aim is to compare the bone stability and overall results between two approaches: adding bone only up to the original bone line (IPD) or adding bone beyond it (over-contour augmentation). Over the course of a year, the study will assess not only bone and soft tissue healing, but also gum blood flow, implant success, and patient satisfaction.

There will be two treatment groups in this study - one group will receive bone grafting just up to their natural bone shape, while the other group will receive a slightly larger graft that extends about 3 mm beyond it. Throughout the study CBCT scans will be taken to assess bone changes around the implant area in order to measure how the bone shape and thickness change over time after surgery.

This is a two-centre, prospective, non-inferiority clinical trial with two parallel study groups aimed at radiographically comparing the differences in hard tissue (lateral augmentation) stability following different GBR treatment protocols (contour augmentation or over-contour augmentation). The study consists of 12 visits over a period of approximately 16 to 18 months.

The study will take place at the Centre for Oral Clinical Research (COCR), at the Institute of Dentistry, Faculty of Medicine and Dentistry, Queen Mary University of London under The Royal London Dental Hospital, Barts Health NHS Trust, United Kingdom (leading centre) and at Implant Research Centre & Department of Periodontology, School of Dental Medicine, University of Belgrade, Serbia, according to local guidelines and procedures/interventions detailed below.

Inclusion Criteria:

• Adult (>18 years old) patients
• Good medical and psychological health
• Engaged patients presenting with a Full Mouth Plaque Score (FMPS) of ≤ 20% within the 6 weeks prior to enrolment
• Need of a tooth/teeth replacement in the incisor, canine or premolar maxillary region that could be provided with an implant-supported fixed prosthesis
• A relatively symmetrical maxillary arch
• A nearly intact contra-lateral alveolar ridge
• At least one neighbouring natural tooth present with healthy periodontal conditions
• After implant placement, presence of a buccal bone dehiscence/ fenestration or buccal bone plate thickness of ≤ 1.5 mm requiring GBR (Monje et al., 2022; Jensen et al.,2023, Group 1 ITI Consensus Report).
• At least 4 weeks of post-extraction socket healing and no ridge preservation prior to implant placement.
• No acute infection at the site; adequate availability of bone apical and palatal to obtain implant primary stability
• A functional occlusion with a minimum of 4 occlusal units (i.e., pairs of occluding posterior teeth)
• Willingness to read and sign a copy of the Informed Consent Form (ICF) after reading the Patient Information Sheet (PIS), and after the nature of the study has been fully explained and potential questions fully answered.

Exclusion Criteria:

• Any known systemic disease severely affecting bone metabolism (e.g., Cushing's syndrome, Crohn's disease, rheumatoid arthritis, osteoporosis or diabetes type I and uncontrolled diabetes type II).
• Self-reported HIV or other severe immunosuppression.
• Self-reported alcoholism or chronic drug abuse.
• Heavy smokers ( > 10 cigarettes/day)
• Patients reporting use of vape/e-cigarettes
• Self-reported pregnancy or lactation
• Chronic treatment (i.e., 2 weeks or more) with any medication known to affect oral status or bone metabolism (e.g., bisphosphonates, hormone replacement therapy, immunosuppressants) within 1 month before baseline visit.
• Chronic treatment with anticoagulants (including Aspirin), corticosteroids, immunosuppressants or other medications that may influence blood coagulation/count.
• Untreated caries lesions in neighbouring teeth and untreated/uncontrolled periodontal disease; If patients require periodontal treatment (non-surgical and/or surgical), this will be arranged outside the study protocol and completed prior to enrolment;
• Physical handicaps that would interfere with the ability to perform adequate oral hygiene in the area of implant placement.
• Patients requiring maxillary sinus lift surgery before implant placement or presenting bone dimensions (at any time point of the study) that do not allow implant placement or there is no clinical indication to perform study procedures (i.e. bone augmentation, implant placement).
• Patients not willing to receive animal-derived biomaterials for GBR.
• Patients suffering from a known psychological disorder or with limited mental capacity or language skills such that study information could not be understood, informed consent could not be obtained, or simple instructions could not be followed.
• Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or may interfere with the interpretation of trial results and, in the judgement of the investigator, would make the subject inappropriate for entry into this trial.

Due to the nature of the intervention, clinicians performing the surgical intervention and primary outcome examiner will be unblinded. Conversely, participants and researchers analyzing secondary outcomes (e.g., intra-oral & extra-oral scans, aesthetic scores) will be blinded to treatment allocation throughout the whole study duration.