Horizontal Alveolar Ridge Augmentation with Xenogenic Block Grafts Compared with Autogenous Bone Block Grafts for Implant-retained Rehabilitation: a Systematic Review and Meta-Analysis.

Objectives: The objective of the present systematic review and meta-analysis was to test the 0-hypothesis of no difference in implant treatment outcome after horizontal alveolar ridge augmentation with xenogenic block compared with autogenous bone block.

Material and methods: A literature search was conducted using PubMed, Embase and Cochrane Library databases in combination with a hand-search of relevant journals until 25^th of January 2022. Comparative and non-comparative studies evaluating horizontal alveolar ridge augmentations with xenogenic blocks were included. Quality and risk of bias were evaluated by Cochrane Collaboration's revised tool and Newcastle-Ottawa scale.

Results: Meta-analysis revealed no statistically significant difference in implant survival rate after more than 6 months of functional implant loading (P = 0.71), no difference in alveolar ridge width (P = 0.07) or gain of alveolar ridge width at re-entry (P = 0.13). Non-comparative studies revealed moderate to high short-term implant survival rate and gain in alveolar ridge width, however, complications including dehiscences, graft exposure and graft failure were observed in several studies.

Conclusions: No significant difference could be identified in short-term implant treatment outcome following horizontal alveolar ridge augmentation using xenogenic block compared with autogenous bone block with the limited data available. A high incidence of healing complications and implant failures necessitates further investigation, as well as long-term results on implant survival rate.