A Primary Study On The Relationship Between Maxillary Protraction Treatment And Changes Of Nasal Profile Of Children With Crossbite

Maxillary protraction is recommended for developing skeletal Classâ…¢patients with maxillary deficiency. For a growing patient who suffers from maxillary retrognathia with or without mild mandibular prognathia, maxillary protraction with a face mask is an adequate treatment method. Maxillary protraction therapy is sometimes combined with palatal expansion in the belief that palatal expansion may disrupt the circummaxillary suture system and thus enhance the protraction effect of the face mask. Since the 1990s, maxillary protraction has been clinical-applied widely. The correcting effect of protraction on maxillary retrognathia is confirmed by many researches. But the relationship between maxillary protraction and nasal profile is not clear yet, and there is not a comprehensive standard evaluating the nasal profile change. What change will take place on nasal profile after maxillary protraction? We design this study to clearify this problem. Part 1:A study on the relationship between maxillary protraction treatment and changes of nasal profile of children with crossbiteAIM:To study the relationship between maxillary protraction treatment and changes of nasal profile of children with crossbite, as so to provide some theoretical reference for treating the patients clinically with maxillary deficiency. METHODS:Twenty-four patients (male 12, female 12, aged 10~12 years) with maxillary deficiencies were selected. All of them had classâ…¢malocclusion. They were divided into 2 groups randomly:Experimental and control groups. The experimental group was given a maxillary protraction treatment with a face mask for 4-8 months, and no treatment was taken on the control group. By measuring the lateral cephalometric radiograph before and after the treatment, differences between the 2 groups were evaluated in a paired t-test. RESULTS:Compared with the control group, significant differences were found in the M-VL, PrN-VL, nasofrontal angle and columella-tip angle in the 2 groups(P<0.05), except the N'-VL and nasolabial angle. CONCLUSION:Besides the effect of correcting the Angleâ…¢malocclusion with maxillary retrognathism, the maxillary protraction also plays a great role in the recontouring of good nose.Part 2:A study of the influence of nasal and lower facial soft tissue change after maxillary protraction treatment on profileAIM:To study the soft tissue change after maxillary protraction treatment of nasal and lower facial profile, as so to provide some theoretical reference for treating the patients clinically with maxillary deficiency. METHODS :Twenty-four patients (male 12, female 12, aged 10~12 years) with maxillary deficiencies were selected. All of them had classâ…¢malocclusion. They were assigned into 2 groups randomly:Experimental and control groups. The experimental group was given a maxillary protraction treatment with face mask for 4-8 months, and no treatment was taken on the control group. By measuring the lateral cephalometric radiograph before and after the treatment, differences between the 2 groups were evaluated in a paired t-test. RESULTS:Compared with the control group,significant differences were found in the PrN-VL, Ss-VL and Ls-VL, Ss-E line and Ls-E line in the 2 groups(P<0.05), except the Li-VL. CONCLUSION:Both the nasal and lower facial profile are dramatically improved after maxillary protraction treatment. The combining effect of these two changes results in a more harmony profile.