拔牙与非拔牙矫治前后牙弓宽度的变化

目的:比较拔牙与非拔牙矫治前、后牙弓前后部宽度的变化。方法:选择50例患者的矫治前后模型作为研究对象,其中25例采取拔除4个第一前磨牙的矫治方法,为拔牙组;25例采取非拔牙矫治,为非拔牙组。观察2组矫治前、后牙弓前后部宽度的变化,采用SPSS11.0软件包进行配对t检验和χ2检验。结果:2组上颌尖牙间宽度均增大,但组间无统计学差异(P>0.05);2组下颌尖牙间宽度均增大,且组间有显著统计学差异(P<0.01);2组第二磨牙间宽度均无变化。结论:与非拔牙矫治相比,拔牙矫治并不会引起牙弓的缩窄。     

拔牙和非拔牙矫治对颊廊影响的研究

目的 研究拔牙和非拔牙矫治对颊廊的影响.方法 随机选取安氏Ⅰ类错(牙合)拔牙矫治患者和不拔牙矫治患者各25例,在其矫治前后的牙(牙合)模型上,分别对上下尖牙区和磨牙区唇颊面最突出的位置进行牙弓宽度的测量,同时在其矫治前后面部正位像上,测量笑容宽度和上颌可见牙列宽度,计算颊廊系数.所有数据均经统计学分析.结果 非拔牙组矫治前后牙弓宽度变化无统计学意义.拔牙组矫治后上、下颌尖牙间宽度分别增加了2.87 mm和1.30 mm(P＜0.05),但上下颌磨牙间宽度的变化无统计学意义.两组治疗前后颊廊系数变化均无统计学意义.结论 对于安氏Ⅰ类错(牙合)患者,拔牙和不拔牙矫治对颊廊均无明显的影响.     

Damon拔牙与非拔牙矫治前后牙弓宽度变化的研究

目的：比较分析采用Damon矫治技术对牙列拥挤病例进行拔牙与非拔牙矫治的牙弓形态变化。方法：15例中度牙列拥挤病例,使用Damon3矫治器进行非拔牙矫治;15例重度牙列拥挤病例,使用Damon3矫治器进行拔牙矫治。对治疗前后的记存模型进行测量分析,讨论牙弓宽度改变特点。结果：采用Damon矫治技术矫治牙列拥挤的拔牙与非拔牙病例均可取得较好的效果,拔牙组上、下颌尖牙间宽度增大,有统计学意义;非拔牙组上、下颌前磨牙宽度以及上颌第一磨牙间宽度增大,有统计学意义。结论：拔牙组牙弓宽度改变主要与牙齿移动方向有关,非拔牙组牙弓宽度改变与拥挤存在部位以及拥挤程度有关。     

拔牙矫治对牙弓宽度及基骨宽度的影响

目的 :研究拔牙矫治对牙弓宽度和基骨宽度的影响。方法 :在 2 0例AngleⅡ1拔牙病例矫治前后的石膏模型上 ,测量上下颌的牙弓长度、尖牙间牙弓宽度、第二前磨牙间牙弓宽度、第一磨牙间牙弓宽度以及相应的基骨宽度 ,测量结果数据用SPSS 10 .0进行统计学分析。结果 :上颌矫治后尖牙间牙弓宽度和基骨宽度明显增加 (P <0 .0 1) ,前磨牙间牙弓宽度和基骨宽度明显减小 (P <0 .0 1)。下颌矫治后尖牙间牙弓宽度不变而基骨宽度增加 (P <0 .0 5) ,第一磨牙间牙弓宽度不变而基骨宽度减小 (P <0 .0 1) ,前磨牙间牙弓宽度和基骨宽度均减小 (P <0 .0 1)。上下颌牙弓长度均减小 (P <0 .0 1)。结论 :牙弓越向远中移动 ,其牙弓宽度增大 ,越向近中移动 ,牙弓宽度减小 ,相应的基骨宽度也发生同样的变化。牙齿的转矩移动 ,会引起基骨宽度的改变。     

下颌第三磨牙对矫治后牙弓长度宽度变化的比较研究

目的:探讨下颌第三磨牙的存失状态对矫治后下颌牙弓长度和宽度的改变。方法:随机抽取符合条件的54例,其中先天缺失下颌第三磨牙胚26例,下颌第三磨牙胚存在的28例。对矫治结束和保持3年后的模型进行下颌牙弓长度和宽度测量,卡方分析。结果:测量分析发现2组病例中,牙弓宽度变化无统计学意义,而下颌牙弓长度2组有显著性差异。有第三磨牙胚组,保持3年后下颌牙弓长度平均增加1.9mm,下前牙拥挤平均为1.5mm,而无第三磨牙胚组下颌牙弓长度增加1.0mm,下前牙拥挤平均为0.7mm。结论:下颌第三磨牙的萌出对下颌牙弓产生一定的压力,增加了下颌牙弓的长度,同时也出现了下前牙拥挤,对非拔牙的边缘性病例和有复发趋势的病例,应尽早拔除第三磨牙。以防止出现术后下颌前牙再度拥挤。     

自锁托槽不拔牙矫治牙弓形态变化的研究

目的探讨和分析采用自锁矫治技术进行不拔牙矫治,治疗前后牙弓形态的变化。方法选择40例牙列拥挤的患者,使用自锁托槽进行不拔牙矫治,对治疗前后的记存模型进行测量,分析矫治前后牙弓形态发生的变化。结果矫治后牙弓长度和宽度均有明显的增加,牙弓宽度增加主要发生在前磨牙区。上颌中切牙唇向前移和第一磨牙发生远中向后移量无显著性差异。牙弓变化与牙列拥挤度显著相关。结论采用自锁矫治技术对拥挤病例进行不拔牙矫治,治疗后牙弓宽度和长度增大,上颌牙弓长度增加由上颌切牙唇向移动和磨牙远中移动共同作用所致。     

非拔牙矫治前后牙弓宽度改变的模型测量分析

目的 研究非拔牙矫治患者矫治前后牙弓宽度的改变.方法 选取牙弓轻度拥挤、采用非拔牙简单排齐的安氏I类错(牙合)患者77例,在模型上测量矫治前后尖牙间及磨牙间的牙弓宽度,并将测量结果进行配对t检验.结果 矫治后上颌尖牙间宽度增加(1.00 1.79)mm,下颌尖牙间宽度增加(0.51±1.66)mm,矫治前后上、下颌尖牙间宽度的改变有统计学意义(P＜0.05).矫治后上颌磨牙间宽度增加(0.23±1.36)mm,下颌磨牙间宽度增加(0.14±1.53)mm,矫治前后上、下颌磨牙间宽度改变无统计学意义(P＜0.05).结论 安氏I类非拔牙矫治患者矫治后上、下颌尖牙间宽度均有增加,而上、下颌磨牙间宽度相对稳定.     

牙列拥挤与前突病例拔牙矫正后牙弓宽度变化对比研究

目的：通过研究尖牙、第一磨牙及第二磨牙间宽度的变化,对比牙列拥挤和牙列前突病例以及年龄因素对拔牙矫治前后牙弓宽度变化的影响。方法：随机选择60例拔除四个第一前磨牙MBT矫治技术治疗患者,分为拥挤组和前突组及16岁以上组和16岁以下组进行对比研究,取治疗前后记存模型进行测量,并经统计学分析。结果：拔除四个前磨牙病例矫治后,磨牙区牙弓宽度均减小,尖牙区牙弓宽度均增加;拥挤组及16岁以下组尖牙间牙弓宽度增加更明显,磨牙区牙弓宽度减小在各组间无明显差异。结论：拔牙矫正后拥挤组及16岁以下组的尖牙间牙弓宽度增加更明显,所以治疗后的保持需要时间更长。     

拔牙与不拔牙矫正治疗对牙弓宽度的影响

目的比较拔牙与不拔牙矫正治疗对牙弓宽度的影响。方法选择25例拔除第一或第二前磨牙的正畸患者,25例未拔牙的正畸患者,测量治疗前后的牙颌模型,记录上、下颌牙弓宽度,其中包括尖牙间、前磨牙间及磨牙间宽度,比较拔牙与不拔牙矫正治疗对牙弓宽度的影响。结果上、下颌尖牙牙弓宽度的比较中,拔牙组比不拔牙组大,上颌大1.79mm,下颌大1.95mm,(P<0.01)。磨牙区牙弓宽度差异无显著性。结论拔牙治疗不会导致尖牙区宽度的减小。     

MBT矫治前后牙弓宽度变化的模型分析研究

目的 分析牙列拥挤患者不拔牙与拔牙的MBT矫治对牙弓宽度变化的影响。方法 选择我院正畸科2008—2011年MBT矫治器治疗的牙列拥挤患者40例。其中轻中度牙列拥挤患者20例,使用MBT矫治器进行不拔牙正畸;中重度牙列拥挤患者20例,使用MBT矫治器进行拔除4颗第一前磨牙的拔牙正畸。测量术前术后石膏模型的牙弓宽度,对矫治前后不拔牙组和拔牙组的测量数据分别进行组内、组间统计学分析。结果 矫治前后不拔牙组:上颌尖牙间宽度增大,上下颌第一前磨牙、第一磨牙间宽度增大,有统计学意义;拔牙组:上颌尖牙间宽度增大,上下颌第二前磨牙、第一磨牙间宽度变小,有统计学意义。矫治前2组上下颌尖牙、第一磨牙间牙弓宽度相近,无统计学差异;矫治后不拔牙组上下颌第一磨牙间牙弓宽度大于拔牙组,有统计学意义,2组上下颌尖牙间牙弓宽度相近,差异无统计学意义。结论 不拔牙矫治牙弓宽度变化与拥挤部位、拥挤程度有关,拔牙矫治牙弓宽度变化主要与牙齿移动方向有关。拔牙矫治后尖牙间宽度不会减小。     

Lip curve changes in females with premolar extraction or nonextraction treatment

Changes in lip curvature resulting from treatment have been largely ignored in orthodontic literature. The focus instead has been primarily directed at retraction of the vermilion border and changes in the nasolabial angle. This study, therefore, was designed to retrospectively analyze changes in the upper and lower lip curves associated with growth and treatment. The lateral cephalometric records of 137 female orthodontic patients were digitized. Sixty-two were treated with premolar extractions and 75 without extractions. The overall extraction group was further divided into subgroups on the basis of the chosen extraction sequence, which included extraction of 4/4, 4/5, or 5/5. Statistical analysis revealed no significant differences in changes in lip curve depth between the two overall samples, relative to either of the two reference lines. This would suggest that an appropriately selected plan, whether extraction or nonextraction, should allow treatment to be carried out without negative effects on the curvature of the lips. Calculation of correlation coefficients and regression analysis suggested that the inherent properties and morphology of the soft tissues themselves are probably the greatest determinants of lip curve behavior with treatment. The midface soft tissues appear to be less dependent on changes in the underlying hard tissues than do the lower face soft tissues. Pretreatment upper and lower incisor positions and angulations and the underlying vertical facial dimension appear to play more significant roles in the behavior of the lower lip than the upper lip.     

Extraction vs nonextraction: arch widths and smile esthetics

Dental casts of 30 patients treated with extraction and 30 patients without extraction of four first premolars were randomly selected to determine changes in arch width as a result of treatment. Arch widths were measured from the cusp tips of the canines, premolars, and molars. Posttreatment arch widths were also measured in the midline at a constant arch depth from the most labial surfaces of the incisors. Standardized frontal photographs of the face taken during smiling of 12 extraction- and 12 nonextraction-treated subjects were evaluated. Fifty laypersons judged the esthetics of the smiles. Intercanine width increased less than one mm in both groups, and there was no difference between the two groups. The interpremolar and intermolar distance in both arches decreased significantly from 0.53 to 0.95 mm in the extraction sample, whereas the interpremolar and intermolar widths increased significantly from 0.81 to 2.10 mm in the nonextraction sample. When arch widths of both groups were measured from the most labial surfaces of the teeth at a constant depth, the average arch width of both arches was significantly wider in the extraction sample (1.8 mm wider in the mandible and 1.7 mm wider in the maxilla). The mean esthetic score and the number of teeth displayed during a smile did not differ between the groups. The results indicate that arch width is not decreased at a constant arch depth because of extraction treatment, and smile esthetics are the same in both groups of patients.