The Effect Of Micro-implant Assisted Rapid Palatal Expansion In Patients With Different Radio-graphic Stages Of Mid-palatal Suture Maturation

Objective:To evaluate the effect of micro-implant assisted rapid palatal expansion(MARPE)in patients with different radio-graphic stages of mid-palatal suture maturation.In this paper,the maxillary skeleton expansion(MSE)is the representative of MARPE.And to explore whether the prediction of prognosis and treatment effect of MAPRE via mid-palatal suture maturation is valid.In order to provide a reference for the clinical application of marpe and the formulation of the follow-up treatment plan after the treatment of marpe.Methods:Patients with maxillary transverse deficiency visiting the Department of Orthodontics,Stomatology Hospital,Jilin University from February 2017 to October2019 were selected,including 28 cases(7 males and 21 females,mean age 15.46±5.53years).According to the fusion of the mid-palatal suture,the patients were divided into two groups: 10 cases in fusion occurred group(OG)including 3 males and 7females with an average age of(19.93±6.85)years old;18 cases in non-fusion occurred group(NOG)including 4 males and 14 females with an average age of(12.97±2.35)years old.Each patient had cone-beam computed tomography(CBCT)images taken immediately after the placement of micro-implants(T1)and the completion of maxillary expansion(T2).The CBCT images were analyzed using the Dolphin Imaging software to evaluate the amount of appliance expansion,skeletal expansion,and other changes.Paired t-test was used for comparison before and after expansion treatment,and independent sample t-test was used for comparisons between the two groups.Results:After MAPRE treatment,the amount of sutural expansion in OG group was3.23 ± 1.45 mm while that in NOG group was 4.97 ± 1.47 mm.There was a statistically significant difference in the percentages of bony expansion efficiency between the NOG group(71±20)% and the OG group(46±18)%(P< 0.05).The micro-implants in the OG group were more inclined to the palatal suture than that in the NOG group(P< 0.01).In addition,after mapre treatment,there is an increase in the nasal cavity width and buccal tipping of the maxillary first molars in both groups.However,there was no significant difference between the two groups(P > 0.05).Conclusion:There is statistically significant difference between the OG group and the NOG group in the bony expansion efficiency.Assessing the radio-graphic stages of mid-palatal suture maturation on CBCT images is a very promising predictor for the prognosis and treatment effect of MAPRE treatment.