A Comparative Study Of The Effect Of Tongue Crib Combined With Chin-cup And Facemask On Anterior Crossbite

Objective:To investigate the influence of the tongue crib combined chin-cup and the facemask on some relevant osteal and odontic measurements as well as the position of the hyoid bone and the pharyngeal airway space and to provide some help and reference for the early correction of anterior crossbite in the future.Methods:The patients with anterior crossbite of the Orthodontic Department of the Affiliated Stomatological Hospital of China Medical University from March 2013 to March 2018 were selected for the treatment.The patients were divided into the tongue crib combined chin-cup group and the facemask group according to the treatment method.Each group had 30 people.The Cephalometric radiographs before and after treatment were analyzed with winceph 9.0 software to compare the skeletal and dental indexes and soft tissue changes between the two groups.Auto CAD 2016 software was used to measure the hyoid bone and airway items on Cephalometric radiographs before and after treatment.SPSS21.0 software was used to analyze the difference before and after treatment and the difference between the two groups with paired sample t test and independent sample t test.Results : 1.After treatment,the ANS-PNS line distance increased,the SNA angle increased,the SN-PP angle decreased(P<0.05),suggesting that the maxillary was growth upwards and forwards,the ANB angle was significantly increased(P<0.01),suggesting that the sagittal positional relationship of upper and lower jaws was significantly improved,the Go-Gn distance and Ar-Go distance were increased(P<0.01),indicating that the mandible still remained growth during treatment.The Y-axis angle?FMA angle?SN-MP angle increased(P<0.05),suggesting that the mandible rotates downward and backward.2.After treatment,the U1-SN angle and U1-NA angle of the two groups increased significantly(P<0.01),suggesting that the upper anterior teeth had libial tipping,the L1-NB angle and L1-MP angle decreased(P<0.05),suggesting that the lower anterior teeth had lingual tipping.The overjet significantly increased(P<0.01).3.After treatment,the upper lip to the E-line of distance of the two groups increased(P<0.05),indicating that the upper labiate process became larger after treatment,the mentolabial angle of tongue crib combined with the chin-cup group increased(P<0.05).4.Hyoid bone position result displayed : the distance of H-S and H-Ar were significantly increased in the two groups(P<0.01),suggesting that the hyoid bone moved downwards,the distance of H-C3 became smaller(P<0.05),indicating that the hyoid bone moved backwards after the treatment.The H-Me distance was no significant change(P>0.05).5.Examination of the PAS changes showed : PNS-UPW distance increased(P<0.01),U-MPW distance increased in tongue crib combined with the chin-cup group,suggesting that the nasopharyngeal airway increased.In the facemask group,PNS-UPW?U-MPW distance increased(P<0.01),suggesting that the nasopharyngeal and upper oropharyngeal airway increased.MT-MTP?EPA-EPP distance decreased,the difference was not statistically significant(P>0.05),Although the lower oropharyngeal and laryngopharyngeal airway decreased,there was no significant change.Compared with the difference between the two groups,the U-MPW distance of the facemask group increased more(P<0.05),indicating that the upper oropharyngeal airway of the facemask group increased more.Conclusions:1.The facemask and the tongue crib combined with chin-cup can both promote the maxillary development,make the mandible rotate backward and backward,effectively correct the anterior crossbite.2.The treatment involving tongue crib with chin-cup and the facemask can both change the location of hyoid bone posteriorly and inferiorly.3.The facemask can enlarge the nasopharyngeal and upper oropharyngeal airway and the tongue crib conbined with chin-cup can enlarge the nasopharyngeal airway after treatment.