Comparison Of Different Techniques In The Treatment Of Class â…¡~1Malocclusion

Objective:Though retrospective study, the purpose of this clinical study was to compare the skeletal,dental,soft tissue changes produced by the Twin-block and Forsus appliances in early adolescent patients with Class Ⅱ1division malocclusion, so as to provide a reference for the selection of appropriate clinical treatment methods.Methods:The study was carried out on60patients (33males,27females) with Class Ⅱ1division malocclusion due to retrognatic mandible. Among these,30were treated with Twin-block,30were treated with Forsus, with an average age of10.9years, early adolescent. Improved Pancherz analysis and other analytical measurements were evaluated changes on each lateral cephalometric radiograph in upper and lower jaw and tooth position in the sagittal direction and relationships.Application SPSS16.0software measurement results after each treatment paired samples t-test and independent t-test was used in data analysis of two groups. Then analyze the test results.Results:This study demonstrated the skeletal, dental and soft tissue effects of the Forsus used in Class Ⅱ1division malocclusion in peak growth period, with an average course of18months, have good growth guidance, and promoting the role of good clinical received treatment.1.Bone changes:1Respectively, compare Twin-block group (The following referred to as the T group) and Forsus group (The following referred to as the F group) before and after treatment:Significant mandible advancement was suggested by Twin-block and Forsus, B-Y, Po-Y, SNB angles were significantly increased, ANB angle decreased (P <0.05); T group and F group were effectively promote the growth of the mandible, Ar-Po, Ar-Go, Go-Gn N-Me and ANS-Me were significantly increased; while maxillary portion improve well.2)There is a significant difference (P＜0.05) in Ar-Go, ANS-Me between two group.3)MP/SN angle in T group becomes larger (P<0.05), while in F group did not change significantly after treatment (P>0.05), but the two groups no comparison significant difference (P>0.05).4) F group and T group had statistically significant changes in the amount of SNA (Δ SNA)、A-X for inter-group comparison(P<0.05).2.Dental changes:1)For both groups, extrusion of the maxillary incisors, protrusion and intrusion with labial tipping of mandibular incisors, distal tipping of maxillary molars, and mesial movement and mesial tipping of the mandibular molars were observed at the end of the treatment.2) Bone and tooth ratio:T group at6.02mm coverage reduction improve quantity and5.40mm molar relationship, tooth effect accounted for54.67%and68.01%, the skeletal effects accounted for45.33%and31.99%; F group at6.70mm coverage reduction improve quantity and5.30mm molar relationship, tooth effect not accounted for57.70%and39.64%, the skeletal effects accounted for42.30%and60.36%.4)Overbite in T and F group changed3.3±0.91mm,3.7±1.94mm.3.Soft tissue changes:Two phase correction method obtain evident curative effects and better side face of soft tissue for chin backwards. There were significant differences in mentolabial suicus and the upper lip(P<0.05).Conclusion:1. Twin-block and Forsus appliances have excellent therapeutic effect in the peak of the growth with mandibular retrusion,which improve the appearance side appearance.2.Compared Twin-block, Forsus promote better in the growth of ramus and the change of condyle in the glenoid fossa, to maintain the mandibular plane angle.3.Compared Twin-block, Forsus has inhibition on the growth of maxillary arch. Forsus promote better in incline.The lower front teeth more pour.4.Twin-block has more molar relationship adjustment and overbite covering mainly caused by tooth effect, Forsus, which adjust the relationship between the front teeth covered mainly by effects caused by bone.5.Compared Twin-block, Forsus could apply. sagittal mandible but also promot the growth and promotion of ramus height. So the mandibular plane angle is essentially the same. Forsus make the anterior lip down-dip easily. Otherwise, lower front teeth moderately crowded, lips inclination larger.