The success and effectiveness of miniscrew-assisted rapid palatal expansion are age- and sex-dependent

OBJECTIVES: This study aimed to assess the success rate and the amount of suture separation after the miniscrew-assisted rapid palatal expansion (MARPE) procedure in relation to the chronological age and sex of the patients. MATERIALS AND METHODS: The periapical radiographs of 215 subjects (95 male; 120 female; range, 6–60 years) who had undergone MARPE treatment were retrospectively analyzed. The success of suture separation was determined and, in suture-separated subjects, the amount of suture separation was evaluated by suture separation ratio calculated from the periapical radiograph obtained after active expansion. Association tests were performed using linear-by-linear association, the Jonckheere-Terpstra test, Fisher’s exact test, and the Mann–Whitney U test, and linear regression models were also developed. RESULTS: The success rate of suture separation was 61.05% in male, 94.17% in female, and 79.53% in both sexes. There was a statistically significant association between older age and suture nonseparation in male (p < 0.001), but not in female (p = 0.221). In suture-separated subjects, there was a statistically significant trend toward a low amount of suture separation with older age subgroups in both sexes (p < 0.001); however, there was no statistically significant difference in the amount of suture separation between male and female in all age subgroups. CONCLUSIONS: Older patients treated with MARPE, particularly in male, may have a reduced likelihood of both success in suture separation and sufficient basal bone expansion. CLINICAL RELEVANCE: This study demonstrates that clinicians should consider that the success rate of MARPE and the amount of suture separation may depend on chronological age and sex. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00784-021-04281-0.