Asymmetry effect of micro-implant assisted rapid palatal expansion on the circummaxillary sutures in patients with mandibular deviation: a retrospective study

Objectives Maxillary transverse deficiency(MTD) is one of the etiological factors of mandibular deviation(MD). Early correction of maxillary transverse deficiency can improve mandibular deviation to a certain extent. Circummaxillary sutures are closely related to maxillary development; however, there is no research on the relationship between the circummaxillary sutures and mandibular deviation in adults. This study aimed to investigate the changes of circummaxillary sutures in patients with MD and MTD after micro-implant assisted rapid palatal expansion (MARPE) and to analyze their correlation with mandibular deviation. Method Fifty-six cone-beam computed tomography scans for 28 patients (mean age 17.92 ± 3.86 years) were evaluated before (T0) and after (T1) MARPE. All patients were diagnosed with mandibular deviation and maxillary transverse deficiency prior to receiving MARPE therapy. The mandibular deviation was diagnosed by the distance between the menton point and the median sagittal plane was greater than 2 mm, then measured the distance at T0 and T1. The width changes of eight circummaxillary sutures (frontonasal, frontomaxillary, frontozygomatic, nasomaxillary, zygomaticomaxillary, zygomaticotemporal, pterygomaxillary, and midpalata sutures) were measured on slices which can ensure the maximum bone sutures width of T0 in each patient. Then track the same level at T1 images measure the width of the sutures and compare it with T0. Comparison of data is based on (1) deviated side: side of the chin. (2) non-deviated side: opposite side of the chin bias. In addition, the correlation coefficient between the changes of menton point to the median sagittal plane and the variation in the circummaxillary sutures was calculated. Results 1. The distance from the menton point to the median sagittal plane decreased in all cases (ΔT1-T0 = -1.40 ± 0.62), and the difference was statistically significant ( P  < 0.05).