| Objective: To use cone beam computed tomography(CBCT)and Dolphin software to evaluate the changes of the upper airway and hyoid bone position before and after the treatment of the MRC muscle function appliance for the treatment of children with Oral Respiration Class Ⅱdivision and I malformation.It is expected to provide an important reference for the clinical selection of MRC muscle function appliances.Methods: In this study,20 children with malformation of Class Ⅱ and Class Ⅰoral respiratory malformation were included in this study.There were 11 males and 9females,with an average age of 8.70±0.9 years.All children received MRC muscle function appliance treatment for 12 months.CBCT was taken before and after treatment.Dolphin software was used for image processing,three-dimensional reconstruction,positioning and analysis.SPSS 23.0 software package was used for data processing and analysis,and pairing was applied.Check the data before and after the treatment,and evaluate the influence of the MRC appliance on the position of the upper airway and hyoid bone.Results:(1)Changes in skeletal characteristics of children before and after MRC treatmentThe results of this study showed that the overall appearance of the upper jaw of the child was normal before treatment,and the mandibular retraction appeared.The SNA angle value did not change significantly after the MRC treatment,and the difference was not statistically significant(P>0.05);the SNB angle value was in the MRC treatment Significant increase after treatment,the difference was statistically significant(P<0.05);the ANB angle value before treatment was significantly larger than the normal value,and after MRC treatment,it decreased from 7.1±1.9 to 4.8±1.3,the difference was statistically significant Significance(P<0.05);the distance between SN-Go Gn angle value and ANS-PNS was not significantly different before and after treatment,and the difference was not statistically significant(P>0.05);while Ar--Gn,Co-Gn,and The distance between Go-Gn increased significantly after treatment,and the difference was statistically significant(P<0.05).(2)Changes of upper airway volume in children before and after MRC treatmentThe results of this study showed that compared with before treatment,the children’s V total,V larynx,V tongue,V palate and V mouth increased significantly after MRC correction,and the difference was statistically significant(P<0.05);V total increased on average V larynx increased by 1214.2±789.4(mm3)on average,V tongue increased by 1322.8±867.5(mm3)on average,V palate increased by 1051.2±774.8(mm3)on average,and V mouth increased by 2517 on average.±1003.7(mm3).The V nose was relatively lower than before treatment,but the difference was not statistically significant(P>0.05).(3)Changes in the cross-sectional area of the upper airway in children before and after MRC treatmentThe results of this study showed that compared with before treatment,the STE,SSP,and Smin upper airway cross-sectional area of the children increased significantly after MRC correction,and the difference was statistically significant(P<0.05);STE increased by an average of 33.8±41.2(mm2);SSP increased by 45.5±39.7(mm2)on average,and Smin increased by 45.2±47.6(mm2)on average;SHP was not significantly different from before treatment(P>0.05).(4)Changes in the transverse diameter of the upper airway of the child before and after MRC treatmentThe results of this study showed that compared with before treatment,the upper airway sagittal diameter APSP increased from 10.2 ± 2.7(mm)to 13.6 ± 3.1(mm),an average increase of 3.4 ± 1.7(mm),the difference was statistically significant(P<0.05),the upper airway sagittal APTE and APHP did not change significantly,and the difference was not statistically significant(P>0.05);compared with before treatment,the upper airway transverse diameter LTE and LSP increased significantly,and the difference was statistically significant Significance(P<0.05),upper airway transverse diameter LTE increased by 5.5±2.5(mm)on average,upper airway transverse diameter LSP increased by 3.4±1.9(mm)on average,and upper airway sagittal diameter LHP before and after treatment Significant difference(P>0.05).(5)Changes of upper airway morphology in children before and after MRC treatmentBy exploring the ratio between the sagittal diameter and the transverse diameter of the upper airway to reflect the changes in the morphology of the upper airway,the results of this study show that the ratio between the sagittal diameter and the transverse diameter of the upper airway is less than 1.It shows that the airway of the child is narrow and long.Compared with before treatment,the ratio of the sagittal diameter to the transverse diameter of the epiglottis apical plane(AP/LTE)after MRC correction decreased from0.404±0.121 to 0.353±0.175,the difference was statistically significant(P<0.05)The ratio of the sagittal diameter to the transverse diameter of the lower soft palate plane(AP/LSP)of the child increased from 0.554±0.236 to 0.623±0.227 after MRC correction,and the difference was statistically significant(P<0.05).There was no significant change in the ratio of the sagittal diameter to the transverse diameter of the hard palate plane(AP/LHP)before and after MRC correction,and the difference was not statistically significant(P>0.05).From the analysis of the results,the ratio between the sagittal diameter and the transverse diameter of the epiglottis apical plane(AP/LTE)decreased,which indicates that the upper airway epiglottis tends to be flat,while the sagittal diameter of the lower soft palate plane(AP/LSP)and the transverse diameter tend to be flat.The ratio between the diameters increases,and the ratio tends to more 1,which indicates that the upper airway tends to be round in the lower plane of the soft palate.(6)Changes in the position of the hyoid bone in children before and after MRC treatmentThe results of this study show that after the patient is treated with the MRC appliance,the vertical distance(H-Mp)and the horizontal distance(H-CVP)of the hyoid bone are both Significant increase,the difference is statistically significant(P<0.001);the results show that after one year of treatment with the MRC muscle function appliance,the hyoid bone position of the children in the growth and development stage shifts forward and downward,and mouth breathing is opposite to the upper airway oropharynx.The impact of the segment has been effectively improved.Conclusion: The MRC muscle function appliance can significantly improve the upper airway morphology and correct the position of the hyoid bone in children with Oral Respiration Class Ⅱ division and I malformation during the dentition period.It has a significant effect and is worthy of clinical application. |
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