Effects Of Mouth Breathing On Craniofacial Morphology And Airway Development In Children

Objective Systematic review and Meta-analysis were used to study the developmental characteristics of maxillofacial bones in children with mouth breathing.Subsequently,cranial lateral radiographs of children with mouth breathing were collected to analyze the degree of adenoid hypertrophy,the development of maxillofacial bones and the characteristics of airway in children with mouth breathing at different cervical ages,so as to provide reference for clinicians.Methods All literatures before February 23,2020 were retrieved for systematic review and meta-analysis.According to the preliminary study results,clinical data of mouth breathing children aged 7-15 who were admitted to our hospital from December 2018 to September 2019 were collected,and 120 children who met the inclusion criteria were screened out.Cephalic radiographs were collected.According to the A/N score of the degree of adenoid hypertrophy,the normal adenoid group,the physiological adenoid hypertrophy group and the pathological adenoid hypertrophy group were divided into three groups.At the same time,CS1-CS6 was divided into six groups according to different stages of cervical spine age and development.Cephalometric analysis was performed on lateral cranial radiographs of each group to obtain the values of each measurement index.The standard values of each index were established,and the independent sample t test was conducted to analyze the characteristics of maxillofacial bone and airway development in children with mouth breathing.In addition,analysis of variance and Q test were used for comparison between groups and correlation analysis of two variables to compare whether there were differences in mouth breathing children under different influencing factors.Results(1)A total of 10 original studies were included in the systematic evaluation and meta-analysis.1358 children aged 2 to 14 years(643 for mouth breathing and 715 for nasal breathing).SNA(Md:-1.63,95%CI:-2.30 to-0.97),SNB(Md:-1.96,95%CI:-2.77 to-1.14),SN-PP(Md: 0.68,95%CI: 0.21 to 1.15),SN-OP(Md: 3.05,95%CI: 2.38 to 3.72),PP-MP(Md:3.05,95%CI: 2.38 to 3.72),4.92,95%CI :4.10 to 5.74),1.NA(MD: 1.96,95%CI: 0.80 to 3.12)was higher than that of nasorespiratory children.SPAS(Md:-3.48,95%CI:-5.52 to-1.43),PAS(Md:-2.11,95%CI:-2.90 to-1.32)and C3-H(Md:-1.34,95%CI:-1.96 to-0.72)were lower in children with oral respiration than those with nasal respiration.(2)A total of 120 children aged 7-15 years were selected.According to the A/N ratio,there were 50 cases in the normal group,34 cases in the physiological adenoid hypertrophy group,and 36 cases in the pathological adenoid hypertrophy group.SAr Go,PNS-UPW and PAS showed statistical significance among groups.The ANB physiological hypertrophy group was larger than the pathological hypertrophy group,SAr Go in adenoid normal group was larger than the pathological hypertrophy group,SAr Go,H Angle and PAS adenoid normal group were smaller than the pathological hypertrophy group,and the values of the PNS-UPW adenoid normal group,the physiological hypertrophy group and the pathological hypertrophy group decreased successively.(3)According to the age stage of cervical vertebra,there were 45 cases of CS1,33 cases of CS2,21 cases of CS3,9 cases of CS4,12 cases of CS5,and 0 cases of CS6.The measured values of SNB,Go Gn and Ar Gn in stages CS1 to CS5 were less than the standard values.The measured values of NGo Me,H Angle,lower lip length and upper lip protress were all higher than the standard values during the whole stage from CS1 to CS5,and the measured values of PNS-UPW in female nasopharyngeal airway during the whole stage from CS1 to CS5 were lower than the standard values.Conclusion(1)After systematic review and meta-analysis,the mandible and maxilla rotated backward and downward in children with mouth breathing,and the occlusal plane was steep.In addition,children with mouth breathing have a tendency to have labial tilt of the anterior teeth and narrow airways.(2)After grouping the adenoids of children with mouth breathing,it was found that mouth breathing can cause hypoplasia of upper and lower jaws,palatal plane and posterior and inferior rotation of mandible,posterior retraction of chin,soft tissue protrusion,lengthening of upper and lower lips,narrowing of nasopharyngeal airway and widening of lower oropharyngeal airway in children.The hypoplasia of maxilla,posterior and inferior rotation of mandible and stenosis of nasopharyngeal airway were positively correlated with the degree of adenoid hypertrophy.(3)After grouped statistical analysis of the age of cervical vertebra,the effect of oral respiration on the maxilla and mandibular ramus of children mainly exists in the early growth and development of children.The shorter mandibular body length and the lower and lower mandibular rotations were observed during the whole development of children.The effect of oral respiration on the upper lip protrusion,the shorter length of upper and lower lips and the retraction of chin in children’s maxillofacial soft tissue existed in each growth and development stage.Female nasopharyngeal stenosis is more likely to be affected at all stages of growth and development.