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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
12
In this group, a bone level implant (Straumann BLC, SLActive®, Roxolid, Straumann AG, Switzerland) will be placed in an ideal 3D prosthetically guided position to allow for a screw-retained restoration, following the manufacturer's protocol. Guided bone regeneration (GBR) will be performed simultaneously with the implant placement with the aim to re-establish the original bone contour as defined by IPD. A bovine bone mineral graft (Bio-Oss collagen®, Geistlich, Wolhusen, Switzerland) will be placed on the buccal aspect of the implant and covered with a collagen membrane (Bio-Gide®, Geistlich, Wolhusen). In the test group, bone augmentation will be performed by adding biomaterial 3 mm beyond the Individual Phenotypical Dimension (IPD) to achieve over-contour augmentation. IPD will be clinically defined during surgery by connecting the most labially prominent points of adjacent ridges at the level of the bone zenith of neighboring teeth.
In this group, a bone level implant (Straumann BLC, SLActive®, Roxolid, Straumann AG, Switzerland) will be placed in an ideal 3D prosthetically guided position to allow for a screw-retained restoration, following the manufacturer's protocol. Guided bone regeneration (GBR) will be performed simultaneously with the implant placement with the aim to re-establish the original bone contour as defined by IPD. A bovine bone mineral graft (Bio-Oss collagen®, Geistlich, Wolhusen, Switzerland) will be placed on the buccal aspect of the implant and covered with a collagen membrane (Bio-Gide®, Geistlich, Wolhusen). In the control group, bone augmentation will be performed by adding biomaterial up to the IPD line in order to achieve a contour augmentation with bone grafting remaining within the boundaries defined by the IPD. IPD will be clinically defined during surgery by connecting the most labially prominent points of adjacent ridges at the level of the bone zenith of neighboring teeth
Barts Health NHS Trust Dental Hospital
London, United Kingdom
Linear dimensional (LD) changes of the buccal aspect of the augmented alveolar ridge
The primary objective is to compare radiographically the differences in the hard tissue stability (linear dimensional changes of the augmented ridge) following guided bone regeneration (GBR) simultaneous to implant placement (IP), when lateral bone augmentation is performed up to Individual Phenotypical Dimension (IPD) (control group) or as an over-contour augmentation beyond IPD (test group).
Time frame: baseline, immediately after implant placement (IP) and 12 months after implant loading (IL)
Cross-sectional area changes of the buccal aspect of the augmented ridge
Cross-sectional area changes of the buccal aspect of the augmented ridge across the whole length of the implant (mm) (ROI) from the time of implant placement (IP) to 12 months after implant loading (IL), assessed by superimposing and comparing CBCT data from different visits.
Time frame: baseline, immediately after IP and 12 months after IL
Blood flow changes
Blood flow changes at baseline, immediately after, and at 1, 3, 7, 15, 30 days after IP
Time frame: baseline, immediately after, and at 1, 3, 7, 15, 30 days after IP
Soft tissue volume changes
Soft tissue volume changes at baseline, immediately after, and at 1, 3, 7, 15, 30 days after IP, immediately after IL, 6 and 12 months after IL
Time frame: baseline, immediately after, and at 1, 3, 7, 15, 30 days after IP, immediately after IL, 6 and 12 months after IL
Extra-oral 3D geometric changes
Extra-oral 3D geometric changes assessed with a facial chairside scanner at baseline, immediately after, 1, 3, 7, 15 and 30 days after IP
Time frame: baseline, immediately after, 1, 3, 7, 15 and 30 days after IP
Full mouth plaque score (FMPS)
FMPS will be recorded as a percentage of total surfaces (6 sites per tooth/implant), which reveal the presence of plaque. A binary score will be assigned to each surface (1 for plaque present, 0 for absent).
Time frame: baseline, 6 and 12 months after IL
Full mouth bleeding score (FMBS)
FMBS will be recorded as percentage of total surfaces (6 aspects per tooth/implant), which reveal the presence of bleeding within 10 - 30 seconds following periodontal probing. A binary score will be assigned to each surface (1 for bleeding present, 0 for bleeding absent).
Time frame: baseline, 6 and 12 months after IL
Probing pocket depth (PPD)
PPD will be measured in mm using a University of North Carolina (UNC-15) periodontal probe at six sites per tooth/ implant (i.e., mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual)
Time frame: baseline, 6 and 12 months after IL
Gingival recession (REC)
REC will be measured in mm using a University of North Carolina (UNC-15) periodontal probe at six sites per tooth/ implant (i.e., mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual)
Time frame: baseline, 6 and 12 months after IL
Clinical attachment level (CAL)
CAL will be calculated considering the values for PPD and REC in mm
Time frame: baseline, 6 and 12 months after IL
Suppuration
Suppuration will be recorded as percentage of total surfaces (6 aspects per tooth/implant), which reveal the presence of suppuration following periodontal probing. A binary score will be assigned to each surface (1 for suppuration present, 0 for suppuration absent)
Time frame: baseline, 6 and 12 months after IL
Implant success/survival
Implant success will be based on well-defined criteria by Albrektsson et al. (1986) and survival defined as any dental implant which remained in situ (ITI consensus 2004) 6 and 12 months after IL. Modified success criteria will be applied to incorporate the aesthetic outcomes in success rates
Time frame: 6 and 12 months after IL
Changes in the pink esthetic score (PES)
Changes in the pink esthetic score (PES) from loading to 6 and 12 months after loading. PES is a cumulative score, where seven variables are evaluated using a 0-1-2 scoring system, with the scores 14 and 0 being the best and the worst outcomes, respectively
Time frame: immediately after IL, 6 and 12 months after IL
Changes in the white esthetic score (WES)
Changes in the white esthetic score (WES) from loading to 6 and 12 months after loading. The WES is a cumulative score where five subgroups are assessed using a 0-1-2 scoring system, with the scores 10 and 0 being the best and the worst outcomes, respectively
Time frame: immediately after IL, 6 and 12 months after IL
Early healing index
Visual assessment of gingival healing and recording of wound healing (Wachtel et al., 2003) will be assessed during follow-ups at 1, 3, 7 and 15 days after the surgical intervention.
Time frame: 1, 3, 7, 15 days after IP
Patient satisfaction
Each patient will be asked to rate their functional and aesthetic satisfaction regarding the overall implant treatment using a subjective outcome questionnaire immediately after IL, 6 and 12 after IL. The questionnaire includes seven questions to be answered in a 5-level Likert scale (poor; fair; good; very good; excellent) (Fava, Lin, Zahran, \& Jokstad, 2015).
Time frame: immediately after IL, 6 and 12 after IL
Life impact questionnaire
Numerical rating scale (NRS) ranging from 0-10 will be complemented with a questionnaire to assess post-surgical pain and swelling at 1, 3, 7 and 15 days.
Time frame: 1, 3, 7 and 15 days after IP
Patients' aesthetic satisfaction
A visual analogue scale (VAS) rating the overall patients' aesthetic perception of final restoration will also be recorded on the day of the implant loading with monolithic zirconia screw-retained crowns to 6 and 12 months after IL (Aitken, 1969). The scale will range from 0 (very poor aesthetics) to 10 (excellent aesthetics) and the subject can indicate the degree of satisfaction by marking vertically across the VAS scale.
Time frame: immediately after IL, 6 and 12 months after IL
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