Periodontal side effects of rapid and slow maxillary expansion: A systematic review

Objectives: To identify the scientific evidence that demonstrates which of the transverse maxillary treatments has the least effect on periodontal tissues. Materials and Methods: PubMed (MEDLINE), Cochrane Library, Scopus, Web of Science, Virtual Health Library, Google Scholar, and OpenGrey were searched without restrictions. A hand search was also carried out in the reference lists of the articles selected. The related articles tool in the PubMed database was checked for each article included. Risk of bias assessment was performed using Cochrane Collaboration's Risk of Bias tool for randomized clinical trials and the ROBINS-I tool for nonrandomized studies of interventions. The GRADE tool was used to assess the quality of the evidence. Results: After examination of the full texts, three studies were finally included. Two studies used a Haas expander with different protocols, and one study used a Haas expander compared with a quad-helix appliance. These studies evaluated periodontal parameters and periodontal indices by clinical examination with a millimeter probe, and one study examined computed tomography images. After quality assessment, two studies were considered as having a low'' risk of bias. One study was scored as having a moderate risk of bias. The evidence was graded as moderate quality for alveolar bone level, tooth displacement, and inclination and very low for all other outcomes. Conclusions: There were no significant differences to enable a sound conclusion about which type of maxillary expansion has the least periodontal side effects.