关于下颌扩弓的实验性研究：牙弓宽度和周长的增加

本研究的目的是估计进行下颌侧向扩展时的牙弓周长的增加量。下颌扩弓通过三维(3D)有限元方法(FEM)和计算机图样技术模拟。侧向扩展时磨牙的旋转中心通过使用3DFEM来计算,几何模型的确定使用了一个东印度人骨骼标本中的下颌骨及间距为1mm厚的计算机体层摄影(CT)。3D排列模拟是通过3D计算机图样技术而不是手工操作来引导的。在后牙段即从第一前磨牙到第二恒磨牙产生了旋转运动,在3D排列模型中通过有限元方法可以     

四圈扩弓簧矫治下颌牙弓狭窄的临床应用

目的：探讨四圈扩弓筑矫治器对下颌牙弓狭窄的扩弓效果,注意事项及适应症。方法：采用插入式下颌四圈扩弓簧矫治器,为下颌牙弓狭窄的患者进行扩弓,矫治器通过焊接在下颌第一磨牙带环舌侧的扁形插槽固.结果:扩弓后第一磨牙间牙弓宽度增加2．0－4．0mm,第二双尖牙间牙弓宽度增加3．0－5．0mm,疗程3－6个月,平均4个月。结论：四圈扩弓筑矫治器对下颌后牙弓的扩弓是肯定有效的,是配合常规固定矫正技术扩弓的有效装置。     

单侧完全性唇腭裂患者磁力扩弓后牙弓宽度的稳定性研究

目的:研究磁力扩弓正畸治疗唇腭裂患者错牙合畸形的临床疗效和稳定性。方法:选择32例恒牙晚期单侧完全性唇腭裂患者,进行磁力扩弓和固定矫治。制取患者治疗前、后和保持2年后的数字化模型,拍摄治疗前、后及保持2年后锥形束CT。对上颌各段牙弓宽度、基骨弓宽度和牙根长度进行测量。结果:磁力扩弓后,上颌各段牙弓宽度以及上颌基骨宽度均有显著增加(P<0.05),其中第一磨牙间的牙弓宽度增加最显著(P<0.01);保持2年后牙弓宽度无明显变化(P>0.05)。扩弓后上颌第一前磨牙的颊根长度变化具有统计学意义(P<0.05)。结论:磁力扩弓和固定矫治相结合,可以较好地扩大唇腭裂患者的上颌牙弓宽度,获得尖窝交错咬合关系和长期稳定性。     

扩弓前后的牙弓变化评价

在牙列拥挤的矫治中 ,是否拔牙一直颇有争议 ,近年来 ,不拔牙矫治又重新被倡导。扩大牙弓是不拔牙矫治的主要方法之一 ,本文就扩弓后牙弓变化的研究作简要综述。     

上下颌联合快速扩弓结合固定矫治器矫治前后牙弓形态变化的研究

目的：研究分析上下颌联合快速扩弓结合 MBT 直丝弓矫治器矫治错(牙合)畸形患者的临床疗效。方法：选择36例进行上下颌联合快速扩弓结合直丝弓矫治器治疗结束的患者,治疗前后分别对每位患者进行模型测量和头影测量分析。结果：矫治后上下颌牙弓宽度和牙弓周长均增加,牙弓宽度增加主要在前磨牙区,牙弓前段深度减小（P ＜0．05）。联合扩弓在骨性垂直方向上的变化无差异（P ＞0．05）,U1-SN、U1-NA 减小,L1-MP、L1-NB 增大（P ＜0．05）。结论：上下颌联合扩弓结合直丝弓矫治技术可以有效地解除拥挤并保持良好的咬合状态,颌骨在垂直方向上没有产生不利影响。     

安氏Ⅱ类2分类错牙合扩弓后牙弓宽度的稳定性研究

目的探讨安氏Ⅱ类2分类错验扩弓矫治后的牙弓宽度的稳定性。方法分别测量17例安氏Ⅱ类2分类错验患者扩弓治疗前后及保持2年磨牙间及尖牙间牙弓宽度。结果安氏Ⅱ类2分类错验患者扩弓治疗前后上下尖牙及磨牙间宽度均明显增大（P〈0．05），保持2年后上尖牙及磨牙宽度基本稳定，而下尖牙间宽度明显缩窄。结论安氏Ⅱ类2分类错验扩弓矫治后，最好用舌侧保持器做永久保持。     

16名中国汉族儿童乳牙列期牙弓和基骨弓研究

目的 研究中国汉族儿童在3～6岁期间乳牙列下颌牙弓和基骨弓的生长发育规律及二者的相关性.方法 在深圳市幼儿园小班(3～4岁)抽取乳牙期汉族儿童75名,连续3年定期追踪,完成检查16名(男孩10名,女孩6名),获得模型48副,进行下颌牙弓及基骨弓生长发育及二者相关性研究.结果 各年龄段牙弓大小差异有统计学意义(P＜0.05),且年龄越大牙弓越大;WC-WC基骨弓大小差异无统计学意义(F=0.71,P=0.556 5),WD-WD和WE-WE基骨弓大小差异有统计学意义(P＜0.05),年龄越大基骨弓越大;各年龄段C/E牙弓比值(F=1.59,P=0.211 8)和C/E基骨弓比值(F=0.34,p=0.795 8)差异无统计学意义.牙弓和基骨弓经Pearson相关性检验,各参数均呈现高度相关性(R＞0.8,P＜0.05).结论 3～6岁乳牙列期中国汉族儿童牙弓和基骨弓大小随着年龄增长而扩大(除了乳尖牙区的基骨弓宽度),但形态上无明显变化,二者形态高度相关.     

安氏Ⅱ类2分类错扩弓后牙弓宽度的稳定性研究

目的探讨安氏Ⅱ类2分类错扩弓矫治后的牙弓宽度的稳定性。方法分别测量17例安氏Ⅱ类2分类错患者扩弓治疗前后及保持2年磨牙间及尖牙间牙弓宽度。结果安氏Ⅱ类2分类错患者扩弓治疗前后上下尖牙及磨牙间宽度均明显增大(P<0.05),保持2年后上尖牙及磨牙宽度基本稳定,而下尖牙间宽度明显缩窄。结论安氏Ⅱ类2分类错扩弓矫治后,最好用舌侧保持器做永久保持。     

上下颌扩弓结合固定矫治技术在安氏Ⅱ类Ⅰ分类错非拔牙病例中的临床应用

目的：探讨上下颌扩弓结合固定矫治技术在安氏Ⅱ类Ⅰ分类青少年非拔牙患者矫治中的临床应用疗效。方法选取21例10~14岁、以下颌后缩为主的安氏Ⅱ类Ⅰ分类错患者,应用上下颌扩弓结合直丝弓矫治技术进行矫治。对治疗前后的模型进行测量,并结合治疗前后X线头颅侧位片和曲面断层片进行分析。结果矫治前后上下颌牙弓宽度的变化有统计学意义(P<0.05),其中前磨牙区的宽度变化最大,其次是磨牙区。牙弓长度减小,头颅侧位片显示骨性侧貌改善明显,下颌前移。结论应用上下颌扩弓结合MBT直丝弓矫治技术在把握好适应症的情况下应用于安氏Ⅱ类Ⅰ分类患者,可以取得良好的效果。     

固定包绕式螺旋扩弓器扩弓对牙弓长度的影响

目的研究固定包绕式螺旋扩弓器扩弓前后牙弓宽度、长度变化及两者间的关系。方法选取上牙弓狭窄患者33例,戴用固定包绕式螺旋扩弓器扩大上牙弓,在扩弓前后的上颌石膏模型上测量牙弓宽度变化和牙弓长度变化。结果扩弓前后牙弓宽度增值为4.58±1.23mm,牙弓长度增值5.64±1.35mm。结论使用固定包绕式螺旋扩弓器扩大上牙弓后,牙弓长度增值大于牙弓宽度增值。     

Maxillary arch changes with transpalatal arch treatment followed by full fixed appliances

Objective:To evaluate short- and long-term maxillary dental arch dimensional changes in patients treated with a transpalatal arch (TPA) during mixed dentition followed by full fixed appliances in the permanent dentition compared with an untreated sample.Materials and Methods:Dental casts and lateral cephalograms obtained from 36 consecutively treated patients before TPA treatment (T₀), after TPA treatment (T₁), after fixed appliance treatment (T₂), and a minimum of 3 years after fixed appliance treatment (T₃) were analyzed. The control group was matched as closely as possible. Arch widths, perimeter, and length, as well as crowding and incisor proclination, were evaluated.Results:In the treated group, intercanine, interpremolar, and intermolar widths and arch perimeter increased significantly at T₁. At T₂, only the intercanine width increase was still significant. At T₃ all arch dimensions decreased, remaining larger than they were at T₀. The arch length increased after T₁, significantly decreased at T₂, and slightly decreased at T₃. The crowding decreased significantly at T₁, was eliminated at T₂, and increased at T₃. At T_3, 50% of the patients showed relapse with crowding ranging from 0.5 to 2 mm. In the control group at T1, only slight changes were noted but crowding increased. At T2, crowding and upper incisor inclination increased but arch length decreased. At T3, intercuspid width, arch perimeter, and arch length continued to decrease, thereby increasing crowding.Conclusion:Maxillary dental arch dimensions changed significantly after TPA followed by treatment with fixed appliances. Relapse occurred to some extent, especially in intercanine width and arch perimeter, but most of the dental arch changes remained stable.     

固定舌弓缩弓法矫治下牙弓过宽6例临床分析

目的：探讨下颌固定舌弓缩弓方法矫治恒牙列下牙弓过宽或合并有下牙弓过宽所致后牙弓宽度不调。方法：用直径1．0mm的不锈钢丝制作下颌舌弓,对下牙弓过宽或合并有下牙弓过宽所致恒牙列后牙牙弓宽度不调病例6例,测量缩弓前后牙弓宽度及观察咬合关系的改变,随访1年。结果：6例患者平均使用下颌固定舌弓4．3个月,均取得明显效果,缩弓前、后双侧下颌第一磨牙及第一、二前磨牙中央窝间距具有显著性差异（p〈0．05）,尖牙牙尖间距差异不显著,观察1年未见复发。结论：下颌舌弓缩弓能有效应用于恒牙列下牙弓过宽患者的矫治,缩小下牙弓宽度,协调后牙弓宽度。     

应用正畸保持器片牙弓夹板治疗颌骨骨折的疗效评价

目的:探讨应用正畸保持器片牙弓夹板治疗颌骨骨折的临床效果。方法:对12例颌骨骨折患者应用正畸保持器片牙弓夹板固定合并颌间弹性牵引治疗,恢复咬合关系后第2周,停止颌间牵引,第4周拆除牙弓夹板,术后1、2、6个月时复查咬合关系,X线检查骨折愈合情况。结果:所有患者咬合关系恢复理想,X线检查显示骨折断端对位良好,骨折愈合良好,患者无不适感。结论:正畸保持器片牙弓夹板具有骨折对位准确、固位稳固、骨折愈合快、美观卫生、配戴舒适、费用低廉、操作简便等优点,适用于单发性、多发性、移位不明显的颌骨骨折。     

Forsus矫治恒牙期安氏Ⅱ类错(牙合)下颌后缩的牙弓及基骨弓宽度的变化

目的应用Forsus治疗已过生长发育高峰期安氏Ⅱ类错（牙合）下颌后缩恒牙期患者,探讨其牙弓及基骨弓宽度的变化。方法临床选择45例（男20例,女25例）恒牙期安氏Ⅱ类错（牙合）下颌后缩患者,年龄15-16．5岁。戴用Forsus矫治器前后制取牙颌模型,测量牙弓及基骨弓宽度。用Spss15．0统计软件对治疗前后的测量结果进行配对t检验。结果戴用Forsus矫治器前后牙弓及基骨弓宽度均增加。结论Forsus矫治器可用于牙弓狭窄患者的扩弓治疗,但扩弓后的远期疗效和稳定性还有待进一步研究。     

Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances

Objective:To identify which dental and/or cephalometric variables were predictors of postretention mandibular dental arch stability in patients who underwent treatment with transpalatal arch and lip bumper during mixed dentition followed by full fixed appliances in the permanent dentition.Materials and Methods:Thirty-one patients were divided into stable and relapse groups based on the postretention presence or absence of relapse. Intercuspid, interpremolar, and intermolar widths; arch length and perimeter; crowding; and lower incisor proclination were evaluated before treatment (T0), after lip bumper treatment (T1), after fixed appliance treatment (T2), and a minimum of 3 years after removal of the full fixed appliance (T3). Logistic regression analyses were performed to evaluate the effect of changes between T0 and T1, as predictive variables, on the occurrence of relapse at T3.Results:The model explained 53.5 % of the variance in treatment stability and correctly classified 80.6 % of the sample. Of the seven prediction variables, intermolar and interpremolar changes between T0 and T1 (P = .024 and P = .034, respectively) were statistically significant. For every millimeter of increase in intermolar and interpremolar widths there was a 1.52 and 2.70 times increase, respectively, in the odds of having stability. There was also weak evidence for the effect of sex (P = .047).Conclusions:The best predictors of an average 4-year postretention mandibular dental arch stability after treatment with a lip bumper followed by full fixed appliances were intermolar and interpremolar width increases during lip bumper therapy. The amount of relapse in this crowding could be considered clinically irrelevant.     

Short- and long-term evaluation of mandibular dental arch dimensional changes in patients treated with a lip bumper during mixed dentition followed by fixed appliances

Objective:To evaluate short- and long-term mandibular dental arch changes in patients treated with a lip bumper during the mixed dentition followed by fixed appliances, compared with a matched control sample.Materials and Methods:Dental casts and lateral cephalograms obtained from 31 consecutively treated patients before (T₀) and after (T₁) lip bumper, after fixed appliances (T₂), and a minimum of 3 years after fixed appliances (T₃) were analyzed. The control group was matched as closely as possible. Arch width, arch perimeter, arch length, and incisor proclination were evaluated. Repeated measures ANOVA was used to analyze changes in measurements over all four time points between treatment and control groups.Results:Arch widths and crowding were always significantly different except at T₂−T₁. At T₁−T₀, only crowding decreased 3.2 mm while intercanine, interpremolar, and intermolar widths increased by 3.8, 3.3, and 3.9 mm, respectively. Changes at T₃−T₂ showed a significant decrease of 2.1 mm for crowding and an increase of 3.5, 2.9, 2.7, and 0.8 mm for intercanine, interpremolar, and intermolar widths and arch perimeter, respectively. Finally, at T₃−T₀, the reduction in crowding of 5.03 mm was significant and clinically important in the treated group. The differences between intercanine, interpremolar, and intermolar widths were also significant (2.1, 3.8, and 3.6 mm, respectively). All those differences favored the treated group.Conclusions:Mandibular dental arch dimensions were significantly changed after lip bumper treatment. At follow-up, all arch widths were slightly decreased, generating an increase of 0.4 mm in crowding, considered clinically irrelevant. Overall changes remained stable after an average 6.3-year follow-up.     

扩弓联合固定矫治后牙(牙合)关系变化的研究

目的 评价扩弓联合固定矫治后青少年患者的牙关系变化及临床疗效。方法 追踪观察采用上下颌扩弓结合MBT直丝弓矫治器矫治完成的青少年患者，共收集到13例患者治疗前后和保持后的石膏模型并对其进行测量，比较治疗前后及保持后的牙弓宽度变化及PAR指数评分。结果 治疗后上下颌牙弓宽度明显增加（P<0.05），其中上颌中段牙弓宽度变化最大，为（6.54±2.48） mm。保持后上颌前中段牙弓宽度虽然减小（P<0.05），但与治疗前比较差异仍具有明显统计学意义。治疗前后各项PAR分值减少差异有统计学意义，保持前后各项PAR分值变化无统计学意义。矫治后等级分类中，极大改善患者7例，改善6例，无改善或变坏0例。结论 对于牙列拥挤伴牙弓狭窄的青少年患者，运用上下颌扩弓联合固定矫治能获得良好的牙关系。     

不同拔牙正畸模式牙弓形态变化的研究

目的 探讨不同拔牙正畸模式下,成人牙弓形态变化的规律.方法 选40例拔牙正畸病例,分为G1组20例:拔除四颗第一前磨牙,其中男13例,女7例,平均22岁;G2组20例:拔除四颗第二前磨牙,其中男8例,女12例,平均24岁.用模型测量观察矫治前后牙弓长度及尖牙区、前磨牙区和磨牙区宽度;用X线头影测量观察矫治前后切牙内收及...