Alveolar Ridge Preservation Using Xenograft Following Tooth Extraction: A Systematic Review and Meta-Analysis

Human extraction socket healing is characterized by a series of cellular and tissue alterations; a blood clot forms inside the extraction socket quickly, which is then replaced by granulation tissue and eventually osteoid tissue. The center of the ridge shifts palatally/lingually as a result of the buccal bone plates in the maxilla and mandible. Alveolar ridge preservation (ARP) procedures were introduced to prevent alveolar ridge atrophy, preserve sufficient bone dimensions to enable implant placement in prosthetically driven positions, and maintain an acceptable ridge contour in areas of aesthetic concern. Different bone grafts have been used for ARP. Hence, this systematic review was carried out to evaluate the existing scientific literature in providing a comprehensive, quantitative analysis on the effectiveness of xenograft as a grafting material for ARP. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines 2020 and was registered in PROSPERO-CRD42024510745. Electronic databases were searched for studies evaluating the effectiveness of xenograft as a grafting material for ARP and reporting outcomes through horizontal ridge width, vertical ridge height, periodontal clinical parameters (like probing pocket depth (PPD), bleeding on probing (BOP), recession, plaque index (PI) and gingival index (GI), radiological evaluations, and associated complications. Quality assessment of included studies was evaluated through the Cochrane risk of bias (ROB)-2 tool. The standardized mean difference (SMD) was used as a summary statistic measure with a random effect model, and p value < 0.05 as statistically significant through Review Manager (RevMan) version 5.3 (Released 2014; The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen). Two studies were selected for the meta-analysis, and five randomized controlled trials (RCTs) that met the eligibility requirements were included in the qualitative synthesis. There was a low to moderate ROB in the included studies. The pooled estimate showed that vertical ridge height (mid-buccal (SMD = -1.89 (-2.46-1.31), mesial (SMD = -0.18 (-0.65-0.29), and distal (SMD = -0.11 (-0.58-0.36)) decreased more with the Ext. alone group, while BOP (SMD = -0.49 (-0.96-0.01)) was more or less similar in both groups. Horizontal ridge width (SMD = 1.15 (0.97-2.05) was better preserved with ARP. Xenograft was clinically and statistically superior (p < 0.05). The funnel plot did not reveal any asymmetry, indicating the absence of publication bias in the meta-analysis. It was found that an extraction socket filled with xenograft resulted in better preservation of alveolar bone dimension, lesser ridge resorption, and provided better soft and hard tissue healing with better satisfactory results. Further clinical studies with a larger sample size and follow-up period should be carried out to assess the secondary outcomes described to obtain overall good quality evidence.