The Comparison Research Of The Permanent Dentition Patients Of Class Ⅱ Hyperdivergent Malocclusion With The Mia Support After Tooth-extraction Treatments On Airway Sagittal Diameter And Hyoid Position

ObjectiveContrast the change of class II hyperdivergent permanent dentition patients under the MIA support after tooh-extraction treatment on craniofacial hard tissue;comparing the differences between class II permanent dentition hyperdivergent facial type and normal Chinese without snoring of the airway sagittal diameter;comparing the changes of the airway sagittal diameter and hyoid position after tooth-extraction treatments of class II permanent dentition hyperdivergent facial type;to investigate that the changes of oral volume effect on the airway structure.To provide certain reference for the research of clinical diagnosis and treatment.Methods22 cases(15 males,7 females)with skeletal class II hyperdivergent permanent dentition patients malocclusion who met the criteria were includedinto this study,aged from 14 to 34 years(19.82±5.90 years),∠ANB 5°~9°(6.82°±1.54°),∠SN-MP 40°~ 55°(45.48°±4.45°),all cases take the design of tooth-extraction and use straight arch wire technique,use the MIA to strengthen the anchorage.The active orthordontic time were 20 to 28 months.After the treatment,both doctors and patients were satisfied with the results.At last there was a good relationship between the anterior and posterior teeth cusp fossa.The sagittal alignment was improved and the vertical direction was controlled.Use cephalometric X-ray films to compare the sagittal dimensions of upper airway and hyoid position of the objects with no snore normal Chinese people.Compare the changes of craniofacial between before and after tooth-extraction treatments.The comparison of class II hyperdivergent facial types under the MIA support before and after extraction treatment on the airway and hyoid position.Analyzed by SPSS 17.0,the measurement data using t test;analysed the correlation between craniofacial,upper airway sagittal diameter and hyoid bone position by Pearson correlation analysis.Results1.Class II hyperdivergent permanent dentition patients of males and females that nasopharynx,plate-pharyngeal,laryngeal pharynx period on airway sagittal diameter were more narrow than no snoring normal Chinese people;females in this study of the glossopharyngeal airways were more narrow too.2.Class II hyperdivergent permanent dentition patients after teeth extraction under the support of MIA that the angel of SNA,ANB and SN-MP and U1-SN are reduced after treatment,the difference was statistically significant(P≤0.05);U1-L1 angle was larger than before treatment,the difference was statistically significant(P≤0.05).3.Class II hyperdivergent permanent dentition patients after teeth extraction under the support of MIA that the airway sagittal diameter of nasopharynx,plate-pharyngeal,and glossopharyngeal airways were more narrow(P ≤ 0.05),laryngeal pharynx was wider than before,but there was no statistically significant difference,P > 0.05.4.Class II hyperdivergent permanent dentition patients after teeth extraction treatment that hyoid horizontal distance and hyoid vertical distance were increased(P≤0.05).5.Class II hyperdivergent permanent dentition patients after teeth extraction under the support of MIA that the changes of Y angle have positive correlation with hyoid horizontal(P ≤ 0.05);there were no correlation between the craniofacial measurements and the sagittal diameter of the upper airway nor the hyoid position(P > 0.05).Conclusion1.Class II hyperdivergent permanent dentition patients after teeth extraction under the support of MIA that the sagittal alignment of the maxillary and mandibular have been improved,the vertical position was effectively controlled.It is suggested that the perfect clinical design of the anchorage and the effective control of the sagittal and vertical direction of the maxillary and mandibular are the basis for the improvement of this kind of malocclusion craniofacial under orthodontic treatment.2.The sagittal diameter of upper airway in each section of class II hyperdivergent permanent dentition patients was more narrow than that of normal Chinese,the results further proved that“the upper airway of the class II hyperdivergent patients was long and narrow”.3.Class II hyperdivergent permanent dentition patients after teeth extraction under the support of MIA that upper airway had been different degrees narrow,the hyoid position was lower than before,although there was no statistically significant difference between before and after treatment,but the results that were adverse to upper airway function well,which are the invisible problem for OSAHS that need us to pay clinic attention.