The Evaluation Of Myofunctional Training On The Patients Of Class Ⅱ~1 Mandibular Retrusion With Mouth Breathing During Growth

Objective:This study researched the effects of myofunctional training therapy to class Ⅱmandibular retrognathia patients with mouth breathing.The data was obtained based on measuring cephalometric X-ray and plaster model and analyzing the elimination of oral breathing habits.And then the effect of the myofunctional training on these cases was discussed in detail.Methods:10 patients who were all class Ⅱ1 mandibular retrognathia with oral breathing during growth were selected from Department of Orthodontics of Qilu Hospital.There were 4 males and 6 females.Their mean age was(9.29± 1.25)years old.They all accepted myofunctional training therapy for(10.67± 1.66)months.They photographed cephalometric X-ray pre-and post-treatment.Their plaster models were obtained simultaneously.This research included three parts.First,soft and hard tissue was analyzed by cephalometric X-ray.Six indicators of soft tissue profile(including 3 angle indicators and 3 linear indicators)and 22 indicators including 16 angle and 6 linear indicators of hard tissue profile were gathered.Secondly,the changes of dental arch length,width,overjet and overbite were analyzed by measuring the model pre-and post-treatment.Finally,eliminate of mouth breathing was evaluated from clinical examination.Result:1.Cephalometric measurement showed that:the ULP decreased(P<0.01),but the NLA,ULL increased(P<0.01,P<0.05,P<0.01).The distance of Ar-Go and Go-Me increased(P<0.05).The angle of SNB also increased(P<0.05)and the angle of ANB and NA-PA decreased(P<0.01).However,the position and axial of upper incisors were not changed compared with pre-treatment,the lower incisors occurred to be lip inclination(P<0.05).The other data had no significant changes between pre-and post-treatment.2.The results of model analysis are as follows.Overjet and overbite were improved after post-treatment(P<0.01).The width and length of upper and lower dental arch were both enlarged(P<0.01).3.Clinical examination of mouth breathing showed that:the positive rate of cotton test was 100%before and after treatment respectively;the positive rate of water test dropped from 100%(T1)to 60%(T2),and the time of the test increased from(106.33±27.83)seconds to(155.33±33.34)seconds(P<0.01);the positive rate of double-side mirror test dropped from 100%(Tl)to 10%(T2).Conclusion:1.Myofunctional training treatment can improve the state of the muscles of the lips,and promote the growth of the mandible in the sagittal direction to improve the soft and hard tissue profile.2.Myofunctional training treatment can improve the overjet and overbite of anterior teeth,and enlarge the length and width of upper and lower dental arch.3.Myofunctional training treatment can break mouth breathing at some extent.