Anchorage In Primary Vs. Permanent Teeth For Rapid Maxillary Expansion In Children: Systematic Review And Meta-Analysis

Background: Rapid maxillary expansion (RME) is a widely used orthodontic technique to correct transverse maxillary deficiencies. Both primary and permanent teeth are commonly used as anchorage for this procedure. However, there is limited evidence regarding differences in skeletal and dental effects or buccal alveolar bone preservation between these anchorage types. Materials and Methods: A systematic review was conducted to compare the skeletal and dental effects of RME using primary or permanent teeth as anchorage. Searches were performed in the following databases: PubMed, Web of Science, Scopus, LILACS, and OpenGrey. The risk of bias was assessed using the Rob 2.0 and Robins I tools. The certainty of evidence was evaluated according to the GRADE system, and meta-analysis was performed with R software. Results: Eight studies were included in the qualitative analysis and five in the quantitative analysis. The risk of bias was low in two studies, moderate in five studies, and high in one study. The certainty of evidence was very low. It was not possible to perform a meta-analysis for the outcome "buccal alveolar bone thickness" due to the lack of available studies, which was limited to only one study. The intermolar width was greater when the anchorage used permanent teeth SMD= -1.24; 95% CI (-2.14; -0.33); p<0.01]. However, this difference may not be clinically relevant. Conclusion: The evidence does not support a clear recommendation for the use of primary or permanent teeth as anchorage in RME, as no clinically relevant differences were observed in skeletal or dental effects. Primary teeth may be preferred when buccal alveolar bone preservation is a priority. Further studies are required to enhance evidence and support clinical decisions.