Three-dimensional Morphological Analysis Of Palate In Mouth-breathing Subjects-a Controlled Study

Objective: In recent years,the prevalence of mouth breathing in school-age children is high,which has been the focus of scholars in various fields.Due to air pollution,adenoid tonsillar hypertrophy,rhinallergosis and other reasons,children have difficulty in nasal breathing.Mouth breathing has become the main breathing mode in many children,which is a pathological change of normal respiratory mode.Adenoid tonsillar hypertrophy is one of the most common causes of mouth breathing,leading to maxillary apical circular arch and narrow arch,high arch of palatal fornix,etc.The clinical treatments of mouth breathing currently include adenoid tonsillectomy,nasal surgery,orthognathic surgery,orthodontic treatment,speech therapy and drug therapy,etc.Children's symptoms and facial pattern can be improved to a certain extent through the treatments of mouth breathing.But at present,the early orthodontic interventions of mouth breathing need the rich clinical experience judgments of orthodontists.There is no definite conclusion about when the early orthodontic interventions can be carried out,and there is also lack of specific reference index in clinical practice.To compare the anatomical characteristics of maxillary arch,identified as inter-molar width,palatal height and palatal volume and surface area,by three-dimensional analysis of digital dental casts between mouth-breathing and nose-breathing subjectsMethods: To include children with mouth breathing and nasal breathing in Chongqing who meet the criteria.Three dimensional data of dental casts were collected and divided into two groups according to breathing mode.All subjects were got impressions by using alginate impression materials(Densply,China),got research models by using noritake super rock materials(Heraeus,Germany).The models were scanned with a 3D laser scanner(D 800,3 Shape A/S,Freedom HD,DOF,Korea),and the accuracy was reported to be 10 mm.The data were reconstructed and measured by Minics 15.0 and Geomagic12.0 software.Between-group differences were tested with the independent sample Student's t-test(p <0.05).Results: A total of 73 children(35 boys and 38 girls)were enrolled in this study,with a mean age of 8.63 ± 0.78 years.In the study group,only inter-molar width was significantly different between males and females(p<0.01).There was no significant difference in all the measurements between different sexes in the control group(p>0.05).Moreover,the inter-molar width and the palatal height of the molar region in males were significantly different between the study group and the control group(p<0.01).In females,inter-molar width and the surface area of palate were significantly different between the experimental group and the control group(p<0.01).Meanwhile,the inter-molar width,palatal volume and surface area in mouth breathing group were significantly smaller than those in control group(p<0.05),but the palatal height of the molar region in mouth breathing group was significantly higher than that in control group(p<0.05).The inter-molar width and palatal volume were positively correlated with the palatal surface area in mouth breathing group(p?0.05).Meanwhile,the inter-molar width and the palatal height in control group were positively correlated with the surface area of palate(p<0.01).Conclusion: Subjects with prolonged mouth breathing showed a significant reduction of the inter-molar width,palatal volume and surface,and a significant increase of the palatal height,leading to a different development of the palatal morphology.The stenosis of the inter-molar width was more pronounced in men.There was a positive correlation between the inter-molar width and the surface of the palate between the two respiratory modes.