Post-extraction dimensional changes: A systematic review and meta-analysis

Aim: To analyse the evidence pertaining to post-extraction dimensional changes in the alveolar ridge after unassisted socket healing. Materials and Methods: The protocol of this PRISMA-compliant systematic review (SRs) was registered in PROSPERO (CRD42020178857). A literature search to identify studies that fulfilled the eligibility criteria was conducted. Data of interest were extracted. Qualitative and random-effects meta-analyses were performed if at least two studies with comparable features and variables reported the same outcome of interest. Results: Twenty-eight articles were selected, of which 20 could be utilized for the conduction of quantitative analyses by method of assessment (i.e. clinical vs radiographic measurements) and location (i.e. non-molar vs molar sites). Pooled estimates revealed that mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed clinically in non-molar sites was 2.73 mm (95% CI: 2.36–3.11), 1.71 mm (95% CI: 1.30–2.12) and 1.44 mm (95% CI: 0.78–2.10), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in non-molar sites was 2.54 mm (95% CI: 1.97–3.11), 1.65 mm (95% CI: 0.42–2.88) and 0.87 mm (95% CI: 0.36–1.38), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in molar sites was 3.61 mm (95% CI: 3.24–3.98), 1.46 mm (95% CI: 0.73–2.20) and 1.20 mm (95% CI: 0.56–1.83), respectively. Conclusion: A variable amount of alveolar bone resorption occurs after unassisted socket healing depending on tooth type.