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.     

上下颌唇挡对替牙晚期儿童牙(牙合)的影响

目的研究上下颌唇挡同时应用对替牙晚期儿童牙(牙合)的影响.方法选择替牙晚期上下牙列轻度或中度拥挤患儿12例,上下颌均采用唇挡治疗8个月,进行治疗前后X线头影测量分析和模型测量分析,并对治疗前后的测量值变化进行配对t检验.结果唇挡治疗后,SNA、SNB分别增加1.02°和0.97°(P＜0.05),上下切牙前移均是牙冠向近中倾斜,而根尖相对固定的控制性倾斜,旋转中心接近根尖.上下磨牙远中倾斜效果不同,上磨牙远中倾斜直立,旋转中心接近牙冠;下磨牙远中倾斜移动,旋转中心接近阻抗中心;上颌磨牙间牙弓宽度、牙弓周径分别增加4.12mm和5.09mm(P＜0.01),下颌磨牙间牙弓宽度、牙弓周径分别增加4.07mm和6.86mm(P＜0.01).结论在儿童生长发育高峰期,唇挡可有效地引起上下颌牙弓横向和纵向变化,减轻或解除上下牙弓拥挤.     

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近年来,许多正畸医生对安氏Ⅱ1错畸形伴下颌前牙轻度唇向倾斜的患者多倾向于不拔牙治疗而运用唇挡这一功能性矫治器进行治疗,这一技术受到人们越来越多的关注。本文就唇挡的作用原理、制作要求、矫治效果及效果的稳定性等几方面加以综述。     

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.     

正畸治疗后牙弓稳定性的追踪研究

目的：探讨正畸治疗后牙弓的稳定性。方法：对正畸治疗后2－8年74例错He畸形患者治疗前后及保持后模型进行弓牙测量。结果：保持后，上基骨宽度较治疗后增加2．11％；上下6－6宽度、下基骨宽度没有显著性变化，其余均出现明显减少；减少百分率最大依次为上下3－3长度（7．79％，7．56％）、上下基骨长度（7．14％，5．12％）、上下牙弓长度（3．91％，3．37％）、上下3－3宽度（2．28％，3．30％）。结论：保持停止后，上下牙弓长度、基骨长度及3－3宽度有不断减少和3－3长度有回复治疗前水平的倾向，而6－6宽度较稳定。     

影响正畸治疗后牙弓稳定性的相关因素探讨

目的　探讨影响正畸治疗后牙弓稳定性的相关因素。方法　对正畸治疗后 2 4～ 97个月 (平均 5 0 .0 5个月 ) 74例错牙合畸形患者治疗前后及保持后模型进行牙弓测量。结果　保持后 ,大部分测量项目男性大于女性 ,但减少百分率无显著差异 ;不同的矫治器类型 (除上下尖牙宽度P <0 .0 5外 )、错牙合类型 (除上牙弓长P <0 .0 1外 )和保持时间组间牙弓测量项目差异无显著性 (P >0 .0 5 ) ;保持后下 3- 3长度减少百分率非拔牙组 (13.4 4 % )和青少年组 (8.93% )分别大于拔牙组 (7.2 2 % )和成年组 (4 .10 % )。结论　保持停止后 ,尖牙间长度、宽度随着年龄的增大不断减少 ;下颌骨的向前生长和过度扩弓是导致下前牙拥挤复发的主要原因之一。     

下颌扩弓结合固定矫治后牙弓和WALA嵴宽度的变化

目的 应用下颌改良扩弓器,结合MBT直丝弓矫治技术治疗处于生长发育高峰期或末期中重度牙列拥挤伴牙弓狭窄的青少年患者,探讨矫治前后下颌牙弓和WALA嵴宽度的变化.方法 对29例10～15岁中重度牙列拥挤伴牙弓狭窄的青少年进行下颌扩弓,下颌为改良式网状支架扩弓器,运用直丝弓矫治技术完成矫治.矫治前后制取模型,采用Andrews关于牙弓,WALA嵴的定点方法测量下颌牙弓及WALA嵴宽度,并对治疗前后的测量结果进行配对t检验.结果 矫治完成后,下颌牙弓和WALA嵴宽度均不同程度增加(P＜0.05).均以第二前磨牙区扩大最多,其次是第一前磨牙区、磨牙区,而尖牙区最小,矫治效果良好.结论 下颌改良扩弓器结合固定矫治对下颌中重度拥挤伴牙弓狭窄青少年患者的矫治效果良好.     

Dental arch dimensions in the mixed dentition: a study of Brazilian children from 9 to 12 years of age

Objective

This study evaluated dental arch dimensional changes of Brazilian children.

Material and methods

Dental casts were taken from 66 children (29 males; 37 females) with normal occlusion selected among 1,687 students from public and private schools aged 9, 10, 11 and 12 years, according to the following criteria: Class I canine and molar relationships; well-aligned upper and lower dental arches; mixed dentition; good facial symmetry; no previous orthodontic treatment. Dental arch dimensions were taken by one examiner using the Korkhaus’ compass and a digital pachymeter. ANOVA test was applied to compare the arch dimensions at the different ages and the t-test was used to compare the arch dimensions of male and female subjects. Arch forms were compared by means of chi-square tests.

Results

Only the maxillary anterior segment length showed a statistically significant increase from 10 to 12 years of age. Males had a significantly larger maxillary depth than females at the age range evaluated. The predominant dental arch form found was elliptical.

Conclusion

In the studied age range, anterior maxillary length increased from 10 to 12 years of age, males had larger maxillary depth than females and the predominant arch form was elliptical.     

唇挡矫治替牙期牙性Ⅱ类错(牙合)伴轻中度拥挤30例疗效分析

目的探讨唇挡对替牙期牙性Ⅱ类错(牙合)伴轻中度拥挤的矫治效果。方法选择2010年1月至2011年3月大庆总医院集团五官医院口腔正畸科门诊就诊的替牙期牙性Ⅱ类错(牙合)伴拥挤患者30例,所有患者上颌均采用唇挡功能矫治器矫治,矫治前、后均取石膏模型,摄X线头颅定位侧位片。对矫治前后的模型数据及X线头影测量数据进行分析。结果矫治完成后,模型测量结果显示:拥挤度变小,牙弓弧形总长度(TAL)、牙弓长度(AD)变大,差异均有统计学意义(P<0.05);X线头影测量结果显示:SNA角(由蝶鞍中心、鼻根点及上齿槽座点所构成的角)、ANB角(由上齿槽座点、鼻根点及下齿槽座点所构成的角)变大,ptm-6距(翼上颌裂点与上第一恒磨牙颊沟点在FH平面上垂足间的距离)变小,差异均有统计学意义(P<0.05)。结论唇挡对替牙期牙性Ⅱ类错(牙合)伴轻中度拥挤有明显的矫形效果。     

替牙期唇腭裂患者的正畸治疗

替牙期是唇腭裂患者正畸治疗的关键时期,牙槽嵴裂植骨与生长改形等都将在此期进行.由于唇腭裂畸形的复杂多样、严重的颅面部生长缺陷,再加上替牙期的特殊性,使得此时期的正畸治疗充满了挑战与争议.因此,笔者就替牙期唇腭裂患者的正畸治疗程序与方法作一综述,以期为临床提供指导.     

不完全性腭裂患者腭裂修复术后乳牙期与替牙期颅面形态变化的对比研究

目的研究不完全性腭裂患者修复术后乳牙期与替牙期的颅面形态差异。方法选择21例乳牙期和20例替牙期不完全性腭裂患者作为两个实验组，两组的性别比例匹配，进行X线头影测量对比分析。结果替牙期相比乳牙期颅底大小、上颌长、下颌大小及各面高均显著增长。上颌矢状向位置、下颌矢状向位置、颅底角下颌角、下颌平面角、上下颌垂直向关系以及面高之比均无显著变化。面突度显著减小。结论随年龄增长腭裂患者颅面部增大，但各部分之间的相互位置关系基本保持不变。     

Spacing in deciduous dentition of Polish children in relation to tooth size and dental arch dimensions

Aim

To assess the prevalence of primary and secondary spacing in the deciduous dentition and its correlation to tooth widths and dental arch dimensions.

Subjects and methods

Dental casts of 50 preschool children free from malocclusion, were analysed. The width of each space was measured as the smallest distance between the proximal surfaces of the neighbouring teeth, parallel to the occlusal plane. Crown width was measured as the greatest distance between the mesial and distal surfaces of the crown, parallel to the occlusal plane. Intercanine widths were measured between cusp tips of upper and lower canines. Intermolar widths were measured between the central fossae of the second molars. Arch lengths were measured from the midpoint between the central incisors to the midpoint between the distal surfaces of the deciduous second molars.

Results

The primary spaces were present in the upper dental arch in 90% children, on the average 2.09 mm in maxilla and 1.25 mm in mandible. Their widths were dependent on upper intercanine width. Secondary spacing was present in 92% children in the upper dental arch (mean 2.86 mm) and 90% in the lower (mean 3.08 mm). Lower secondary spacing was correlated to lower intercanine width and lower arch length. Total absence of interdental spacing was found in 4% children.

Conclusions

Interdental spacing of the deciduous dentition is present in 96% of Polish children. Children with wider intercanine widths have wider primary spaces in maxilla and wider secondary spaces in mandible.     

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。     

Meta-analysis on the mandibular dimensions effects of the MARA appliance in patients with Class II malocclusions

Objectives:To evaluate the short- and long-term effects of the mandibular anterior repositioning appliance (MARA) on mandibular dimensions in patients with Class II malocclusion and to assess the stability of the MARA results.Materials and Methods:Multiple electronic databases were searched for articles published in any language until March 2014. A manual search was also performed of reference lists of retrieved articles. The primary outcomes were the short-and long-term effects of the MARA appliance on mandible dimensions. The secondary outcome was postretention stability. Outcome measures were total mandibular unit length, corpus length, and ramus height. Two reviewers examined all articles independently and assessed their methodologic quality. Meta-analyses were conducted using random-effects models. The Cochrane test and the I² statistic were used to assess heterogeneity. Sensitivity analyses were performed and publication bias was evaluated.Results:Seven retrospective clinical controlled studies that compared MARA with controls were included. Three of the studies were medium quality; the rest were low quality. Meta-analysis of the short-term effects revealed a significant increase in total mandibular unit length (1.16 mm/y) and ramus height (1.58 mm/y) with MARA and a nonsignificant increase in corpus length (0.21 mm/y). Analyses of the long-term effects showed a statistically significant advantage of MARA over controls for all three variables, but the effect sizes were small. More high-quality studies are warranted.Conclusions:The MARA appliance produced statistically significant mandibular growth enhancement in the short- and long-term. These findings, however, may not be clinically significant.     

儿童先天性肌性斜颈患者下颌骨对称性评估

目的：分析儿童替牙期先天性肌性斜颈患者颅面部对称性，评估颅面结构与颈部结构间相关关系，探讨颈部结构、功能改变对颅面部生长、发育的影响。方法：选择替牙期先天性斜颈20例，拍摄头颅后前位定位片，测量、分析双侧下颌骨形态、位置对称性。结果：先天性肌性斜颈患者颏部向受累侧偏斜，偏斜侧下颌骨体部长度较对侧减小，下颌升支长度、髁突宽度、髁突高度与对侧无显著性差异。下颌骨各解剖标志点位置对称性分析结果表明：先天性肌性斜颈患者下颌骨双侧解剖标志点位置差异较大，表现为相对面下部垂直基准线（ANS-Me）及水平基准线（HRL），对侧各解剖点位置向患侧旋转，从而加剧了偏斜侧垂直高度较对侧减小的程度。结论：先天性肌性斜颈可以导致下颌骨发育畸形，颈部结构与功能对下颌骨的生长发育存在重要影响作用。     

PAR指数评价萌出诱导器对混合牙列中期错的矫治疗效

目的采用PAR指数研究萌出诱导器对混合牙列中期错畸形患者的矫治疗效。方法采用前瞻性队列研究设计,纳入混合牙列中期牙列轻度拥挤、安氏I类或II类患儿56例。试验组(29例)采用萌出诱导器进行矫治,直至上前牙排齐;对照组(27例)不作处理,仅随访观察。采用PAR指数评价试验组治疗前后、对照组随访前后模型数据。结果试验组患者矫治后PAR加权后总分减少率为67.49%±13.47%,对照组随访前后PAR加权后总分减少率为18.69%±12.99%。两组患者在前牙排列、磨牙关系、覆覆盖关系改善上的差异均存在明显统计学意义(P<0.05)。结论萌出诱导器可以改善混合牙列中期患者上下前牙排列,纠正磨牙关系,明显减少患儿覆盖。     

Association between breastfeeding duration,non-nutritive sucking habits and dental arch dimensions in deciduous dentition: a cross-sectional study

Background

This cross-sectional retrospective study was conducted to determine association between breastfeeding duration, non-nutritive sucking habits, dental arch transverse diameters, posterior crossbite and anterior open bite in deciduous dentition.

Methods

415 children (228 males and 187 females), 4 to 6 years old, from a mixed Indian population were clinically examined. Based on written questionnaire answered by parents, children were divided into two groups: group 1 (breastfed for <6 months (n = 158)) and group 2 (breastfed for ≥6 months (n = 257)). The associations were analysed using chi-square test (P < 0.05 taken as statistically significant). Odds ratio (OR) was calculated to determine the strength of associations tested. Multivariate logistic regression analysis was done for obtaining independent predictors of posterior crossbite and maxillary and mandibular IMD (Inter-molar distance) and ICD (Inter-canine distance).

Results

Non-nutritive sucking (NNS) was present in 15.18% children (20.3% in group 1 as compared to 12.1% in group 2 (P = 0.024)). The average ICD and IMD in maxilla and average IMD in mandible were significantly higher among group 2 as compared to group 1 (P < 0.01). In mandible, average ICD did not differ significantly between the two groups (P = 0.342). The distribution of anterior open bite did not differ significantly between the two groups (P = 0.865). The distribution of posterior crossbite was significantly different between the two groups (P = 0.001). OR assessment (OR = 1.852) revealed that group 1 had almost twofold higher prevalence of NNS habits than group 2. Multivariate logistic regression analysis revealed that the first group had independently fourfold increased risk of developing crossbite compared to the second group (OR = 4.3). Multivariate linear regression analysis also revealed that age and breastfeeding duration were the most significant determinants of ICD and IMD.

Conclusions

An increased prevalence of NNS in the first group suggests that NNS is a dominant variable in the association between breastfeeding duration and reduced intra-arch transverse diameters which leads to increased prevalence of posterior crossbites as seen in our study. Mandibular inter-canine width is however unaffected due to a lowered tongue posture seen in these children.     

Rapid maxillary expansion followed by fixed appliances: a long-term evaluation of changes in arch dimensions

The purpose of this longitudinal study was to evaluate the short- and long-term changes in dental arch dimensions in patients treated with rapid maxillary expansion (RME) followed by fixed edge-wise appliances. The records of 112 patients in the treated group (TG) were compared with those of 41 untreated controls. Serial dental casts were available at three different intervals: pretreatment (T1), after expansion and fixed appliance therapy (T2), and at long-term observation (T3). The mean duration of the T1-T2 and T2-T3 periods for the TG group was three years two months +/- five months and six years one month +/- one year two months, respectively. Treatment by RME followed by fixed appliances produced significantly favorable short- and long-term changes in almost all the maxillary and mandibular arch measurements. In comparison with controls, a net gain of six mm was achieved in the maxillary arch perimeter, whereas a net gain of 4.5 mm was found for the mandibular arch perimeter of treated subjects in the long term. The duration of retention with a fixed lower appliance in the posttreatment period did not appear to affect the long-term outcomes of the treatment protocol significantly. The amount of correction in both maxillary and mandibular intermolar widths equaled two-thirds of the initial discrepancy, whereas treatment eliminated the initial deficiency in maxillary and mandibular intercanine widths. The amount of correction for the deficiency in maxillary arch perimeter was about 80%, whereas in the mandible a full correction was achieved.     

恒牙列早期单侧完全性唇腭裂术后患者牙特征的研究

作者对332名恒牙早期间侧完全性唇腭裂术后患者和同龄正常青少年的牙模型进行测量分析，结果表明：①上颌牙弓、基骨的生长发育受到明显影响，其中腭盖高度发育受限最为明显。②上颌牙弓前段宽度发育受限程度明显大于牙弓后段，上颌结节区宽度缩窄不明显。③上颌与下颌牙弓、基骨关系不协调。