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。     

Dermatoglyphic Assessment in Subjects with Different Dental Arch Forms: An Appraisal

Successful rehabilitation of edentulous individuals involves selection and arrangement of artificial teeth in accordance with the patient’s original arch form. Various criteria exist for harmonious tooth arrangement but none is accepted universally. Finger and palm prints are unique to an individual and once formed in the sixth week of intra-uterine life, remain constant thereafter. Since dental arches are also formed during the same prenatal period, it is believed that the similar genetic factors may be involved in formation of dental arches and dermal patterns. This study was conducted to identify the association if any between type of dental arch forms and type of dermatoglyphic patterns. If specific dermal characteristics exist in individuals with specific dental arch forms, dermatoglyphic assessment of long standing edentulous subjects may help identify the patients preexisting dental arch form and thus aid in proper tooth arrangement. Ninety dentulous subjects were categorized into three groups on the basis of dental arch form (square, tapering or ovoid) and their finger and palm prints were recorded. The type of fingertip patterns, distribution of palmar patterns, Total Finger Ridge Count and angle atd were assessed. Subjects with square arches demonstrated a significantly high frequency of loops and a large atd angle with palmar patterns being most frequent in I₃ region. Subjects with tapering arches showed a high frequency of whorls, a small atd angle and greatest distribution of palmar patterns in I₄ region. In ovoid arched subjects, loops were the most common and palmar patterns were mostly observed in I₄. Since distinctive dermal patterns were observed in subjects with different dental arch forms, it is believed that dermatoglyphics may be used as a reliable tool for identifying original arch form in edentulous patients.     

Development and Biomechanical Investigation of a New Compound Palatal Arch

BACKGROUND AND AIM: There are many advantages in using a transpalatal arch in orthodontic treatment. In addition to the active movement of individual teeth, such an arch can be used to provide additional anchorage. The aim of this study was to further develop and improve both the clinical and the biomechanical properties of the conventional transpalatal arch. MATERIAL AND METHODS: Currently available compound material components form an established part of orthodontic therapy. The Compound palatal arch broadens the scope of this treatment system. The biomechanical effects of the newly developed Compound palatal arch were verified by comparing them with those of commercially available conventional transpalatal arches. The recently developed Compound palatal arch is made of one compound element: nickel-titanium/stainless steel. The specific dimensions and design of the nickel-titanium element are aimed at exploiting its superelasticity, even during active molar movement. The biomechanical investigation was carried out using six-component measuring sensors to register the forces and moments in the three spatial dimensions (x, y and z) at 37 degrees C. The following appliances were investigated: Goshgarian transpalatal arch, quad-helix appliance, Arndt memory expander, and Compound palatal arch. RESULTS: Transpalatal arches could not be inserted without the arch being under tension. This is particularly important when the arch is being used for anchorage purposes. The Goshgarian arch had to be classified as problematic for the movement of single teeth as the load/deflection rate was high. However, this can be utilized for anchorage purposes. The clinical advantage of a quad-helix appliance is the option for asymmetric tooth movement. CONCLUSIONS: This study showed that the quad-helix was effective for both unilateral and bilateral derotation as well as for transversal tooth movement. However, expansions should be confined to < or = 4 mm, and derotations to < 10 degrees, as forces and moments are otherwise not within the physiologic range. The Arndt memory expander displayed no advantages over either the quad-helix appliance or the Goshgarian transpalatal arch. Nor did it display any superelastic properties. The linear relationship, the relatively high forces and moments, and the lack of clinical adjustability cast doubts on the benefits of this appliance. The newly developed Compound palatal arch showed substantial advantages in molar derotation compared with conventional transpalatal arches. Superelastic properties were achieved through the design and positioning of the nickel-titanium element. Expansion with the Compound palatal arch was comparable with that with conventional transpalatal arches. The clinical advantage is in the fact that this appliance can be reactivated and that dental asymmetries can be treated.     

20例错牙合正畸治疗和保持后的模型分析研究

目的：评估错He畸形经治疗和保持后牙弓的变化情况，为临床治疗同类错He提供依据。方法：选择拔除4颗第一双尖牙的患者20例，采用方丝弓技术治疗。对治疗前后和保持器停截1年后的模型进行测量。结果：治疗前后除上下牙弓尖牙宽度增加外，其余指标均不同程度减少，去除保持器1年后，上下尖牙宽度和前牙覆He，覆盖出现复发，而上下牙弓中，后段宽度和上下牙弓长度继续减少。结论：治疗后上颌尖牙宽度净增加量较下颌稳定，经治疗和保持后，上下牙弓宽度和长度并非一定会复发。     

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。     

A review of the shortened dental arch concept focusing on the work by the Käyser/Nijmegen group

summary The aims of this paper were to review the literature on shortened dental arches with special focus on publications of the Käyser/Nijmegen group, and to evaluate the discussions on the shortened dental arch concept found in the literature. A MEDLINE (PubMed) search was conducted for articles in English published in the dental literature from 1966 to November 2005. The search revealed epidemiological, cross‐sectional and longitudinal clinical studies as well as opinion papers, the majority of which were published by the Dutch group. The studies found in general no clinically significant differences between subjects with shortened dental arches of three to five occlusal units and complete dental arches regarding variables such as masticatory ability, signs and symptoms of temporomandibular disorders, migration of remaining teeth, periodontal support, and oral comfort. The findings from cross‐sectional studies were corroborated longitudinally. No systematic clinical study with conflicting results was found. The shortened dental arch concept was accepted by a great majority of dentists but not widely practised. The studies reviewed showed that shortened dental arches comprising anterior and premolar teeth in general fulfil the requirements of a functional dentition. It may therefore be concluded that the concept deserves serious consideration in treatment planning for partially edentulous patients. However, with ongoing changes, e.g. in dental health and economy, the concept requires continuing research, evaluation and discussion. Patients’ needs and demands vary much and should be individually assessed but the shortened dental arch concept deserves to be included in all treatment planning for partially edentulous patients.     

偏[牙合]伴反殆患者治疗前后牙弓形态变化的研究

目的：分析与比较偏颌伴反[牙合]畸形矫治前后的牙弓形态变化。方法：选择偏颌伴反[牙合]畸形病例9例,制取矫治前后石膏模型。将模型平行于基准平面扫描到计算机。应用计算机测量软件测量上下颌尖牙、前磨牙和磨牙牙尖的纵横坐标值,分析牙弓矢向和横向的对称性、上下牙弓的协调性。采用SPSS11．0进行统计学分析。结果：矫治前上颌尖牙和第一前磨牙距腭中缝的距离偏向侧大于偏离侧（p〈0．05）,下颌从尖牙到第二磨牙偏向侧距中线的距离小于偏离侧（p〈0．05）;上颌尖牙和第一前磨牙的牙弓宽度比率较矫治后小（p〈0．05）,上颌第二前磨牙和第一磨牙的牙弓宽度比率矫治前后无统计学差异（P〉0．05）;上颌偏向侧和偏离侧牙齿的矢向位置变化无统计学差异（p〉0．05）,下颌牙齿在矢状方向第一磨牙偏向侧大于偏离侧（p〈0．05）。结论：偏颌畸形患者上牙弓前部较下牙弓前部窄,矫治易先扩大上颌牙弓,使得矫治后上下牙弓宽度比例协调。     

Neuromuscular evaluation of post-orthodontic stability: an experimental protocol

To prevent relapse after orthodontic treatment, retention is often considered indispensable. Soft tissues are thought to have a significant influence on dental movements. To quantify the influence of masticatory muscles on post-treatment relapse, and in an attempt to avoid unnecessary procedures, 2 male orthodontic patients (13 and 30 years old at debonding) were followed up. The patients completed 2 years of fixed orthodontic treatment and received no post-orthodontic retention. After 1 week and again after 6 months, alginate impressions of dental arches and a surface electromyographic (EMG) assessment of the masseter and temporalis muscles during maximum voluntary clenching were performed. The younger patient received surface EMG monitoring once a month for the first 6 months and at the 1-year follow-up appointment. Arch dimensions and the 3-dimensional inclination of the facial axis of the clinical crown (FACC) were measured using a computerized digitizer. Symmetry in muscular contraction was measured by the percentage overlapping coefficient (POC), and potential lateral displacing components were assessed by the torque coefficient (TC). At the 6-month follow-up, no clinical modifications were observed. Quantitative evaluation assessed that arch dimensions had changed slightly (up to 1 mm). While the adolescent patient had no modifications in FACC inclinations, the 30-year-old patient showed significant alterations (up to 18 degrees). In all examinations of the adolescent patient, POC was higher than 86% and TC was lower than 10%. In the adult, POC was inside the normal range, while all TCs were higher than 10.5%. The larger TC measured in the adult may explain the larger modifications in the 3-dimensional position of his dental crowns. In conclusion, a surface EMG assessment may help in the detection of patients who might need post-orthodontic retention.     

少牙畸形患者牙弓长度和宽度的临床研究

目的研究少牙畸形患者牙弓的长度和宽度,为临床诊治提供参考。方法选取少牙畸形与正常的牙模型各50副,用游标卡尺测量并计算牙弓长度和宽度的各项参数,采用ANOVA法进行统计分析。结果少牙畸形患者较正常的上、下牙弓长度分别少4.40mm和2.80mm,上、下颌尖牙宽度分别少2.82mm和2.70mm,上、下颌磨牙宽度分别少3.40mm和1.80mm。两组测量项目的差异均有统计学意义(P<0.01)。结论正畸治疗时,应当考虑到少牙畸形患者的牙弓长度和宽度均较正常小。     

腭裂术后裂隙内骨桥长度与牙He横向发育

目的 研究腭裂术后腭裂隙内骨桥形成现象对牙He横向生长发育的影响。方法 随机选取13-28岁单侧完全性唇腭裂术后患者31例。行冠状位CT检查确定腭裂隙内骨桥形成长度后，在牙He石膏模型上分别定点测量牙弓宽度、骨基宽度和牙弓协调度，计算各项测量指标的均值，分析骨桥形成长度与牙He生长发育的关系，并行统计学检验。结果 在腭裂术后骨桥形成长度8mm以上组，其骨基宽度，尤其是牙弓后份的骨基宽度发育明显优于骨桥形成量小于8mm组。在双尖牙区，有效长度的骨桥形成组的牙弓宽度明显大于对照组，而在磨牙区，两组均值间差异无显著性。在双尖牙区，骨桥形成不良者出现较为明显的反He倾向；在磨牙区，骨桥形成不良者并不因此而发生咬合关系紊乱。结论 腭裂术后腭裂隙内骨桥形成的现象明显影响牙He生长发育，对骨基宽度、牙弓宽度和牙弓协调度的发育均有支持作用。骨桥形成影响牙He生长发育的临界长度为4mm，有效长度为8mm。     

Difference in dental arch size between obese and non-obese patients with obstructive sleep apnoea

Summary A large tongue is recognised as a factor that increases the collapsibility of the upper airway in obstructive sleep apnoea (OSA) patients. We hypothesised that the propensity to develop severe OSA could be minimised if the dental arches were enlarged in obese OSA people who are thought to have a large tongue. We therefore compared the size of the dental arches in obese and non‐obese OSA patients. Using a lateral cephalogram and study models, we compared the sizes of the tongue and dental arches in 23 obese and 23 non‐obese Japanese male OSA patients, who were matched for age, apnoea hypopnea index (AHI) and maxillomandibular size. The median age (years) and AHI (events per hour) for the obese and non‐obese groups were 36·5 and 39·0, and 13·4 and 14·3, respectively. The maxillomandibular size was matched with regard to SNA, SNB and lower face cage obtained from cephalometric measurements. The parameters that were measured for the study model included dental arch width, dental arch length, overjet and overbite. Tongue size (P < 0·05) and both upper (P < 0·01) and lower (P < 0·05) dental arch widths were significantly larger in obese than in non‐obese OSA patients, and there was no difference in the severity of OSA between the two groups. These findings suggest that the tongue was larger and dental arches were enlarged in obese patients compared with non‐obese patients under the same disease severity. Wider dental arches in obese OSA patients may help to offset the impact of the enlarged tongue on upper airway patency.     

Shape of dental arches and their dimensions in children without malocclusion aged 3 years

The dental arches were analysed in 3-year-old children without malocclusion evaluating the shape of arches, measuring their with, length and depth. The index of the dental arch and the palatal index were calculated. In children aged 3 years the shape of the upper dental arch was in most cases similar to a semi-ellipse and that of the lower arch approached parabole. This suggests that the semicircular shape of dental arches is not characteristic of this period of occlusion development.     

半坡博物馆馆藏六千年前人类牙弓形态研究

目的：通过对西安半坡出土6000年前新石器时期人颌骨的相关研究,了解该时期人的牙弓特征.方法：选取保存较完整的上颌骨94个,下颌骨98个.对牙弓进行三维测量,并对牙弓形态进行观测.结果：报告了该批次标本上下颌牙弓形态的各项测量数据及非测量性状的观测结果.牙弓形态主要以椭圆形为主,Terra牙列指数分析上下牙弓均大于现代人,上颌牙弓宽度变化更为明显.结论：为进一步研究人类颌骨演化积累数据资料.     

Diastemata in 3-year-old children without malocclusion

In children aged 3 years without malocclusion the dental arches were studied for the occurrence, position and size of diastemata (interdental clefts). In the studied children most arches had diastemata (in 95% of cases in the upper arch and in 80% in the lower arch). It is concluded that the behaviour of the contact points between teeth is not a characteristic feature of the teeth of children aged 3 years. It seems that the presence of "closed" dental arches--without diastemata, and "open" with diastemata, confirms the presence of two types of dental arches of milk teeth.     

Arch width after extraction and nonextraction treatment.

An undocumented criticism of extraction treatment is that it results in narrower dental arches when compared with nonextraction therapy. Anterior and posterior arch widths of the maxillary and mandibular arches of 25 patients treated by 4 first-premolar extraction and 25 patients treated without extractions were measured on posttreatment study models and compared statistically to determine whether the dental arches were narrower after extraction treatment, to test the accuracy of this view. Measurements were made in the canine and the molar regions from the most labial aspect of the buccal surfaces of the canines and the molars. In both groups, anterior and posterior arch widths were the same except for the mandibular intercanine dimension, which was 0.94 mm larger (P <.01) in the extraction group. This indicates that extraction treatment does not result in narrower dental arches than nonextraction treatment.     

An assessment of the fit of a parabolic curve to pre- and post-treatment dental arches

Study casts of the teeth are routinely used for diagnosis and to assess treatment change: the crowding of the teeth or shortage of space available within the dental arch is usually assessed visually. A full cast analysis program has been developed previously, making use of the three-dimensional Reflex Plotter linked to a computer. This study examines the validity of the fit of computer generated parabolic curves to dental arches, as performed in the measurement of crowding. Using a visual analogue method it was found that the parabola appeared to fit lower post-treatment dental arches best. However, reservations regarding the fit of symmetrical curves are expressed and other solutions suggested.     

Replacement of missing teeth in a southern region of Vietnam — a descriptive dental laboratory study

Aim : To explore whether tooth replacement in a southern region of Vietnam is in line with the primary health care approach, aiming at health services for all people at affordable costs. Methods : Tooth replacement was investigated by means of prostheses as delivered by four dental laboratories of which the output was considered representative. Information was based on dental casts related to the prostheses. Results : Prostheses replaced almost all missing teeth, irrespective of the types (interrupted or shortened dental arches) and numbers of missing teeth in the dental arch they were made for. Acrylic removable partial dentures were the most common prostheses delivered (65% of removable partial dentures). Conclusion : It cannot be stated that dental arch conditions in this study were representative for the southern Vietnamese population. However, it is concluded that dental practitioners tend to provide complete dental arches by tooth replacements. This morphologically based approach might introduce over treatment. In line with primary oral health care, a functionally oriented treatment management, including the shortened dental arch concept, should be implemented.     

老年人动态咬合下的接触特征的初步研究

目的：通过研究老年人多种颌位的咬合观察及前伸咬合运动中前牙的接触模式与牙弓形状的关系,探讨老年人的动态咬合下的接触特征,为临床修复重建提供理论依据。方法：本研究共86例老年患者,通过口内视诊确定牙弓形态。采用厚度为8um的Bausch咬合测试膜检查下颌各个非正中颌位的接触：侧方移动至包括下颌0.5mm、尖对尖接触位置及前伸移动至前牙切对切接触位置。结果：下颌侧方移动至0.5mm时,30.2%受试者为双侧组牙功能,20.1%为混合尖牙保护和组牙功能。下颌侧方移动至尖对尖接触位置时,45.3%的受试者为双侧尖牙保护,17.4%为双侧组牙功能。下颌向前滑动至上、下前牙切对切接触位置时,80.2%的受试者前牙存在接触,后牙分离。前牙的牙合接触模式与牙列形状的关系：71.4%方圆型牙弓受试者是I型前牙接触模式;63.9%尖圆型牙弓受试者为II型前牙接触模式;对于卵圆型牙弓受试者,前牙接触模式I型和II型均占40%。结论：老年患者具有特殊的动态接触特征。前伸咬合运动中前牙的接触模式与牙弓形状关系密切,修复重建需要考虑这种关系。     

The form of the dental arch according to the Tweed-Merrifield philosophy: individualization and attempt at standardization

A literature review reveals that changes from the initial arch form lead to a proportionate amount of subsequent relapse and that there is great variation among human arch forms. A persistent search for the ideal arch form is still going on. Many authors presented different techniques for its individualization. A new software ("Arch form generator") was developed to create the arch form following the Tweed-Merrifield concepts. The form and dimensions of 169 mandibular arches were evaluated along with Angle classification and facial type as variables. The reliability of the Ricketts pentamorphic arch forms was questioned and a new arch guide was developed as part of a trial for standardization. The Class III cases showed greater width and smaller cuspid depth when compared to the Class I and Class II cases. The hypodivergent cases showed greater width when compared to the hyperdivergent and normodivergent cases. There is no characteristic form for the human dental arch.