Soft tissue angle evaluation of fixed Twin-Block appliance treatment and tooth extraction treatment in skeletal Class Ⅱ malocclusion

Abstract

Abstract: PURPOSE: This cephalometric study was designed to evaluate the soft tissue profile effects of Twin-Block combined with straight wire appliances in the treatment of skeletal Class Ⅱ malocclusion with mandibular retrognathia in growing individuals by angulation. METHODS： The sample comprised 31 growing individuals with skeletal Class Ⅱ and mandibular retrognathia, which were divided into 2 groups. One group (18 patients) was treated with fixed Twin-Block combined with fixed appliance， the other group (13 patients) was only treated with fixed appliance after tooth extraction. Pretreatment and posttreatment lateral cephalograms were taken before and after Twin-Block treatment and after all the fixed appliance treatment. Angular cephalometric measurements of soft tissue were analyzed statistically. Intragroup and intergroup changes of the 2 groups were evaluated by Student’s t test using SPSS 15.0 software package. RESULTS: Significant difference of FH-N’Pg’, G-Pn-Pg’, LiSi-SN and SnLs-SiLi were discovered in both groups (P<0.05). With Twin-Block combined with fixed appliance, N’-Sn-Pg’, Sn-N’-Si and Si-N’-S changed significantly, while LsSn-SN and Z angle differed significantly before and after treatment with extraction and fixed appliance. After treatment of Twin-Block combined with fixed appliance, Sn-N’-Si decreased significantly, and the difference between the change of the 2 groups was significant. Meanwhile LsSn-SN was stable in combined treatment group while it decreased greatly after extraction. CONCLUSIONS: Compared with extraction with fixed appliance treatment, Twin-Block combined with fixed appliance treatment is more favorable in promoting lower facial profile in growing skeletal Class Ⅱ individuals with mandibular retrognathia.

Key words: Skeletal Class Ⅱ malocclusion, Twin-Block appliance, Tooth extraction, Soft tissue angular cephalometric analysis

CLC Number:

R783.5

GONG Yao, LI Pei-lun, WANG Hong-hong, YU Quan, WEI Bin.. Soft tissue angle evaluation of fixed Twin-Block appliance treatment and tooth extraction treatment in skeletal Class Ⅱ malocclusion[J]. Shanghai Journal of Stomatology, 2016, 25(1): 82-86.

References

[1] Moyers RE, Riolo ML, Guire KE, et al. Differential diagnosis of Class Ⅱ malocclusions. Part 1. Facial types associated with Class Ⅱ malocclusions [J]. Am J Orthod, 1980, 78(5): 477-494.
[2] McNamara JA Jr. Compennents of Class Ⅱ malocclusion in children 8-10 years of age [J]. Angle Orthod, 1981, 51(3): 177-202.
[3] 邹冰爽, 曾祥龙, 曾应魁. 安氏Ⅱ1类错颅面类型的研究 [J]. 口腔正畸学, 1998, 5(2): 13-16.
[4] Vargervik K, Halovold EP. Response to activator treatment in Class Ⅱ malocclusion [J]. Am J Orthod, 1985, 88(3): 242-251.
[5] Teuseher U, Stoekli P. Combined activator-headgear orthopedics[C]//Orthodonties: current principles and techniques [M]. St.Louis: C.V. Mosby Co.,1985: 405-480.
[6] Gaumond G. Hyperpropulsor activator[J]. J Clin Orthod,1986,20(6): 405-411.
[7] Darendeliler MA, Joho JP. Magnetic activator device Ⅱ (MAD Ⅱ) for correction of Class Ⅱ, division 1 malocclusions [J]. Am J Orthod, 1993, 103(3): 223-239.
[8] McNamara JA Jr, Huge SA. The Fr?nkel appliance(FR-2): model preparation and appliance construction [J]. Am J Orthod, 1981, 80(5): 478-495.
[9] Owen AH 3rd. Morphologic changes in the sagittal dimension using the Fr?nkel appliance [J]. Am J Orthod,1981, 80(6): 573-603.
[10] McNamara JA Jr. JCO Interviews Dr. Jmaes A. McNamara Jr. on the Frankel appliance. Part l-Biological basis and appliance design [J]. J Clin Orthod, 1982, 16(5): 320-337.
[11] McNamara JA Jr. JCO/interviews Dr. Jmaes A. McNamara, Jr. on the Frankel appliance. Part 2-Clinical management[J]. J Clin Orthod, 1982, 16(6): 390-407.
[12] Fr?nkel R. The treatment of Class Ⅱ, division 1 malocclusion with functional correctors [J]. Am J Orthod, 1969, 55(3): 265-275.
[13] Lund DL Sandler PJ. The effect of Twin-Blocks: a prospective controlled study[J]. Am J Orthod Dentofacial Orthop,1998,113(l): 104-110.
[14] Mills C, McCulloch KJ. Treatment effects of the Twin-Block appliance: a cephalometric study [J]. Am J Orthod Dentofacial Orthop, 1998, 114(l): 15-24.
[15] Clark WJ. The twin block technique: a functional orthopedic appliance system[J]. Am J Orthod Dentofacial Orthop,1988, 93(l): l-18.
[16] Langford NM Jr. The Herbst appliance [J]. J Clin Orthod, 1981, 15(8): 558-561.
[17] Pancherz H. The effect of continuous bite jumping on the dentofacial complex: a follow up study after Herbst appliance treatment of Class Ⅱ malocclusion [J]. Eur J Orthod, 1981, 3(1): 49-60.
[18] 宫耀, 于泉, 李佩伦. 下颌前导矫形与单纯拔牙矫治对骨性Ⅱ类错畸形的疗效评价 [J].上海口腔医学, 2014, 23(5): 597-601.