正畸牙移入牙槽突裂患者植骨区的牙CT评价

目的应用牙CT评价正畸牙移入牙槽突裂患者植骨区后牙槽骨的形态变化。方法对3位牙槽突裂患者在植骨前后和正畸治疗后行牙槽突裂裂隙区的三维牙CT检查,分析正畸牙移入植骨区域后,正畸牙位置及牙槽骨的形态变化。结果牙槽突裂植骨术后,正畸牙可以顺利移入植入骨区域,正畸牙的牙根尖位置发生明显的位移,牙槽骨会随正畸牙的移动发生塑形改变,而不仅仅是牙齿在牙槽骨内的移动。结论牙槽突裂植骨及正畸治疗有益于重建牙弓的完整性。     

唇腭裂患者牙槽突裂的正畸治疗程序探讨

目的:唇腭裂伴牙槽突裂的上颌骨牙列矫正,常存在牙槽突裂隙区牙槽骨塌陷、牙龈高位、植入骨吸收等不理想状态,本研究回顾性分析8例患者,探讨上颌骨牙列矫治的治疗程序.方法:8例单侧牙槽突裂患者,在牙槽突裂植骨术同期行尖牙骨皮质切开,术后以正畸方法快速将尖牙向颌方、唇向移动,牙根移入植骨区.术前、术后1周、尖牙正轴完成后拍摄曲面体层片、尖牙根尖片、上颌咬合片和尖牙区照片,比较治疗前后尖牙区植骨量、尖牙牙根吸收程度和松动度变化;测量裂隙侧尖牙和邻牙之间的龈缘高度差和牙根之间的夹角,采用SPSS 17.0软件包对治疗前后各测量项目进行配对t检验,比较治疗前后结果有无统计学差异,评价植骨效果以及尖牙移动的有效性和安全性.结果:治疗后牙槽突裂植入骨高度均位于相邻牙牙根长度的1/2以上;裂隙侧尖牙牙根与邻牙牙根基本平行,牙根吸收均<2mm,龈缘高度较治疗前改建良好.结论:该治疗程序具有较强优势,在一次手术的基础上,使尖牙安全、有效进入裂隙区,保证了植入骨的丰满度和高度,重建了正常龈缘.     

唇腭裂二期牙槽突植骨二维与三维影像评价方法的对比分析

目的　探讨二维X线片与CT扫描及三维重建在评价唇腭裂二期牙槽突植骨疗效中的一致性。方法　选择唇腭裂二期牙槽突植骨术后半年以上的唇腭裂 9例 (单侧完全性唇腭裂 8例 ,双侧完全性唇腭裂 1例 ) ,牙槽突裂隙为 10侧。年龄范围 12～ 2 6岁 ,平均年龄 15 5岁。患者首先拍摄上颌前部咬合片 ,经Bergland分级标准确定为 :Ⅰ型 :2侧 ;Ⅱ型 :2侧 ;Ⅲ型 :5侧 ;Ⅳ型 :1侧。在上颌前部咬合片拍摄后的 2个月内 ,进行上颌骨CT扫描及三维重建。结果　上颌前部咬合片所示裂隙植骨区牙槽骨的高度被CT证实。CT检查发现有 2个裂隙植骨区存在唇、腭侧凹陷。结论　唇腭裂牙槽突植骨后 ,在正畸前仍然可以使用上颌前部咬合片进行牙槽突植骨疗效的评价。但同时应注意观察X线片植骨区牙槽骨的密度和临床检查 ,必要时应该进行CT检查     

牙槽突裂区周围牙槽骨形态的研究进展

我国是唇腭裂的高发国家,大多数唇腭裂患者同时患有牙槽突裂。有研究显示裂隙区邻近牙的牙槽骨水平较低;同时,植骨术前正畸治疗有可能导致已经降低的牙槽骨水平继续吸收。所以明确近牙槽突裂区牙牙槽骨形态,对于把握术前正畸治疗牙齿移动的限度有重要意义。锥形束电子计算机X射线断层扫描技术(cone-beam computed tomography, CBCT)在牙槽骨的定量研究中表现出很好的准确性和可重复性,相比传统二维的根尖片有着巨大的优势。本文就牙槽突裂区周围的牙槽骨形态作一综述。     

牙槽突裂植骨术后上颌前部(牙合)片与CBCT评价方法的比较研究

目的 比较三维CBCT与传统上颌前部(牙合)片评价牙槽突裂植骨疗效的差异性.方法 选择唇腭裂二期牙槽突裂植骨术后三个月以上的患者39人,共计49侧裂隙.同期拍摄以裂隙为中心的上颌前部(牙合)片和牙槽突局部CBCT,根据Bergland分级标准对上颌前部(牙合)片进行植骨区牙槽突评价,并与CBCT评价结果进行比较,判断两者一致性.结果 20侧植骨区牙槽突高度为Bergland Ⅰ型和18侧BerglandⅡ型者中,牙槽突厚度分级为A1B1C1D1型者分别有9侧(45.00％)和3侧(16.67％).在上颌前部(牙合)片的评价中,45.00％ Bergland Ⅰ型和16.67％ BerglandⅡ型患者植骨区牙槽突情况与CBCT评价结果一致.55.00％ BerglandⅠ型和83.33％ BerglandⅡ型患者植骨区牙槽突情况被高估.结论 三维CBCT与传统上颌前部(牙合)片对牙槽突裂植骨疗效评价结果不一致.CBCT可以更好的评价牙槽突裂植骨疗效.     

CT在唇腭裂二期牙槽突植骨疗效评价中的应用

目的 探讨唇腭裂二期牙槽突植骨后牙槽骨三维结构,以确保唇腭裂牙槽突植骨术后正畸 治疗的顺利进行。方法 选择唇腭裂二期牙槽突植骨术后半年以上的唇腭裂患者７名,病人的唇腭类型 分别为：单侧完全性唇腭裂６人,双侧完全性唇腭裂１人,牙槽突裂隙为８侧。病人的平均年龄为１５岁, 年龄范围 １１岁至 ２６岁。ＣＴ扫描平面与　面平行,从眶下缘至牙冠的根 １／３,每 ２毫米扫一层并进行三维 重建。结果ＣＴ可以真正反映唇腭裂牙槽突植骨部位的三维结构,能够发现唇腭侧存在的骨骼缺陷,有 利于唇腭裂序列治疗的顺利进行。结论 唇腭裂牙槽突植骨后,正畸治疗前采用ＣＴ这一先进手段进行 裂隙部位牙槽骨高度的三维评价,对于牙槽突植骨后正畸治疗及唇腭裂序列治疗具有十分重要的意义, 使牙槽突植骨的评价进入了三维时代。     

唇腭裂二期牙槽突植骨二维与三维图像评价方法的对比分析

目的：探讨二维X线片与CT扫描及三维重建在评价唇腭裂二期牙槽突植骨疗效中的一致性。方法：选择唇腭裂二期牙槽突植骨术后半年以 上的唇腭裂9例（单侧完全性唇腭裂8例，双侧完全性唇腭裂1例），牙槽突裂隙为10侧。年龄范围12－26岁，平均年龄15．5岁。患者首先拍摄上颌前部啼合片，经Bergland分级标准确定为：Ⅰ型：2侧；Ⅱ型：2侧；Ⅲ型：5侧；Ⅳ型；1侧。在上颌前部咬合片拍摄后的2个月内，进行上颌骨CT扫描及三维重建。结果：上颌前部咬合片所示裂隙植骨区牙槽骨的高度被证实CT证实。CT检查发现有2个裂隙植骨区存在唇、腭侧凹陷。结论：唇腭裂牙槽突植骨后，在正畸前仍然可以使用上颌前部咬合片进行牙槽突植骨疗效的评价。但同时应注意观察X线片植骨区牙槽骨的密度和临床检查，必要时应该进行CT检查。     

牙槽突裂植骨术后鼻外形的改变

目的：通过比较单侧牙槽突裂植骨手术前后鼻外形的变化,评价牙槽突裂植骨术在鼻畸形矫治中的作用。方法：通过人体学测量25例单侧牙槽突裂患者术前、术后即刻及随访6个月的外鼻形态,主要测量指标为健、患侧鼻孔宽度和高度,鼻翼基底宽度及两侧鼻翼基底连线与内眦连线的夹角,应用SPSS18.0软件包,对测得的数据进行配对t检验。结果：25例患者行牙槽突裂植骨手术后患侧鼻孔宽度为（11.61±2.18）mm,大于术前的（10.28±1.83）mm;高度为（4.52±1.19）mm,小于术前的（5.81±1.18）mm;患侧鼻翼基底均高于术前,与术前相比有显著差异（P〈0.01）。随访6个月后,虽形态有向术前回复的倾向,与术前相比仍有显著差异（P〈0.01）。结论：牙槽突裂植骨术后鼻翼基底的变化是植骨成功与否的一个重要指标,适量的超充填可弥补术后骨质吸收,为以后的鼻畸形整复提供一个对称的基底。牙槽突裂植骨后,鼻孔宽度和高度均有变化,故不主张在牙槽突裂植骨同期或之前行鼻畸形整复术。     

牙槽突裂植骨吸收率的测量分析

目的:应用螺旋CT三维重建比较牙槽突裂植骨术后不同时间骨量的变化及吸收率。方法:选取单侧完全性牙槽突裂患者,应用螺旋CT三维重建患者术前牙槽突裂隙,利用GE AW4.1软件感兴趣区(ROI)体积测量法对其术后1周、3个月、6个月的牙槽部植骨进行体积测量,获得体积变化数据。结果:术后3个月,植入骨量丧失35.74%;术后6个月,植入骨量丧失55.89%,且在牙槽部颊侧形成良好骨桥的前提下,植入骨在空间上仍有不同程度的吸收,在腭侧较少有骨桥形成。结论:牙槽突裂植入骨存在一定吸收,而且随着时间推移,骨量吸收相应增加。     

唇腭裂二期牙槽突植骨的评价与正畸治疗——附病例报告

目的 :了解二维X线片与三维CT扫描在评价唇腭裂二期牙槽突植骨疗效中的一致性以及与正畸治疗的关系。方法 :选择唇腭裂二期牙槽突植骨术后半年以上的唇腭裂患者 9名 (UCLP8人 ,BCLP 1人 ) ,牙槽突裂隙为 10侧。病人的平均年龄 15 .5岁 ,年龄范围 12至 2 6岁。病人首先拍摄上颌前部咬合片 ,经Bergland分级标准确定为 :I型 ,2侧 ;Ⅱ型 ,2侧 ;Ⅲ型 ,5侧 ;N型 ,1侧。在上颌前部咬合片拍摄后的两个月内 ,进行上颌骨CT扫描及三维重建。结果 :上颌前部咬合片所示裂隙植骨区牙槽骨高度被CT证实。CT检查发现有 2个裂隙植骨区存在唇、腭侧凹陷。结论 :进行唇腭裂牙槽突植骨后正畸前 ,仍然可以使用上颌前部咬合片进行牙槽突植骨疗效的评价。但是同时还应注意观察X线片植骨区牙槽骨的密度和临床检查 ,必要时应该进行CT检查。     

On tooth movements and associated tissue alterations related to edentulous areas and bone defects

The aim of the thesis was to study orthodontic tooth movement in relation to edentulous areas and infrabony pockets as well as the physiological movement of teeth facing an edentulous area. A dog model was used in Studies I and II. Teeth were orthodontically moved into and out from inflamed, infrabony periodontal pockets (Study I) and into areas of reduced bone height (Study II). Clinical, radiographic and histometric analyses were made with respect to changes in tooth-supporting tissues. Study III involved clinical, radiographic and 3D model assessments of changes in periodontal conditions and alveolar ridge dimensions in adult patients subjected to tooth movement into areas with reduced ridge dimensions. In Study IV, panoramic radiographs of 292 subjects, taken at an interval of 12 years, were analyzed with regard to changes in the elongation of unopposed molars and tipping of molars facing a mesial edentulous space. In the animal study orthodontic bodily movement of teeth with inflamed, infrabony pockets caused an enhanced rate of progression of the periodontal lesion (Study 1), particularly when the tooth movement was directed towards the infrabony defect. Teeth with healthy periodontium that were orthodontically moved into areas of markedly reduced bone height maintained their periodontal tissue support (Study II). Corresponding orthodontic tooth movement in humans (Study III) resulted in minor dimensional alterations of the periodontal tissues and an increased bucco-lingual width of the alveolar ridge in the area into which the tooth had been moved, whereas a decreased width of the newly established edentulous area was noted. All teeth that were moved showed lateral root resorption at the level of the bone crest on the pressure side, but signs of repair were noticed 1-year post-treatment. In the 12-year radiographic study (Study IV) unopposed molars showed a significant increase in elongation over the 12 years of follow-up. The degree of elongation increased with decreased bone support. Neither edentulous space nor alveolar bone level were found to have a significant effect on tipping. In the presence of both conditions, unopposed molars and molars facing a mesial edentulous space, an increase in elongation was associated with tipping.     

Usefulness of the bodily movement of the tooth into the hydroxyapatite-packed extracted cavity

Early application of bodily movement of teeth at an unfinished stage of the healing of the extracted wound i.e. ossification is presumed to increase the risk of jiggling. Using adult dogs, an experimental study was made on bodily movement in the case of HAp packing into the extracted wound cavity to avoid jiggling. When tooth movement was performed immediately after extraction and HAp packing, no encapsulation of HAp with fibrous connective tissue was noted. Either for a weak force or for a strong force, the moved tooth lacked alveolar septum on its compressed side, its dental root being in direct contact with the HAp mass. Remarkable enlargement of periodontal cavity on the tension side and strong osteoclastic resorption of proper alveolar bone were noted. When tooth movement was clone one week after extraction and HAp packing, Either for a weak force or for a strong force, the extracted wound surface was sealed and the HAp mass in the extracted wound cavity got encapsulated by fibrous connective tissue. Alveolar septum has disappeared completely on the compressed side of the moved tooth. Fibrous connective tissue lay between the dental root and the HAp mass and presented its partial osteogenesis. Vigorous bone apposition was noted in the proper alveolar bone surface on tension side. When tooth movement was done one month after extraction and HAp packing, definite ossification was noted in fibrous connective tissue which encapsulated the HAp mass in the extracted wound cavity. Alveolar septum on the compressed side of the moved bone presented resorption and disappearance. For a weak force, gradual ossification was noted in fibrous connective tissue which lay in the same region, and for a strong force, osseous adhesion to the HAp mass was noted. On the tension side, bone apposition was remarkable in proper alveolar bone surface either for a weak force or for a strong force. The above findings revealed thus most suitable time to begin tooth movement was one week after extraction and HAp packing.     

Numerical experiments on long-time orthodontic tooth movement.

In orthodontic treatment, teeth are moved by the use of specific force systems. The force system used depends on the patient's orthodontic situation characterized by the geometry of the tooth and the surrounding alveolar bone, which defines the position of the center of resistance. Therefore, the simulation of bone remodeling could be helpful for the treatment strategy. In this study, the optimal force system for bodily movement of a single-root tooth, with an orthodontic bracket attached, was determined. This was achieved by the use of the numerical finite element method, including a distinct mechanical bone-remodeling algorithm. This algorithm works with equilibrium iterations separated in 2 calculation steps. Furthermore, a parametric 3-dimensional finite element model, which allows modifications in the root length and its diameter, is described. For different geometries, the ideal moment-by-force ratios that induce a bodily movement were determined. The knowledge of root geometry is important in defining an optimal force system.     

A study of the anterior portion of the palate as it relates to orthodontic therapy.

1. The anterior portion of the palate does not appear to move lingually as orthodontic forces move incisor teeth lingually. Although the alveolar bone directly supporting the teeth can be moved distally (and elongated), it does not appear possible to move the apex of the root more distally than the pretreatment position of the palatal plate. Thus, there appears to be an anatomic limitation to the distal movement of maxillary incisor teeth. 2. When incisor teeth are moved distally within the boundaries of the present alveolar process, the supporting bone does not remodel to the roots' new position; when a root which was initially positioned nearer the labial alveolar plate is moved distally against the palatal plate, there was observed no adaptation in the bone to have the root once again located near the labial alveolar plate, the root remained stable against the palatal plate. 3. When great distal movement of incisor teeth results in an alteration in position of the supporting alveolar bone, remodeling of the bone maintains a relatively constant labiolingual width of this alveolar bone. The new position of the tooth and supporting bone appears to be stable. 4. The scanty metallic implant evidence would seem to support histologic observations that alveolar processes are remodeled by apposition of bone on the cortical plate toward which the tooth is moving and resorption of the cortical plate away from which the tooth is moving. 5. There does not appear to be a statistically significant correlation between posterior facial measurements (SNMP) and the labiolingual width of the anterior palate.     

Bone dehiscence formation during orthodontic tooth movement through atrophic alveolar ridges

ObjectivesTo test the null hypothesis that there is no difference in bone dehiscence formation before and after orthodontic tooth movement through an atrophic alveolar ridge.Material and MethodsThis longitudinal retrospective study evaluated pretreatment and posttreatment cone-beam computed tomography imaging of 15 adult patients. Twenty-five teeth were moved through the atrophic alveolar bone, whereas 25 teeth not subjected to translational movement were considered controls. The distances between the cementoenamel junction and the alveolar bone crest were assessed at the mesial, distal, buccal, and lingual surfaces of all of these teeth. Data were compared using the Wilcoxon test. The Spearman correlation test and multivariate linear regression analysis were also performed.ResultsIn general, crestal bone height was reduced around 0.5 mm in all groups in every direction. Median buccal dehiscence increased significantly (+2.25 mm) (P < .05) in teeth moved through the atrophic ridge. Control teeth also had buccal crest loss (+0.83 mm), but this was not statistically different from that of the experimental teeth. Lingual dehiscence increased significantly for the experimental (+0.17 mm) and control (+0.65 mm) groups. Mesial bone height decreased more in the control group (–0.44mm) than in the experimental group (–0.14mm). There was moderate correlation between amount of tooth movement and alveolar bone loss.ConclusionsThe null hypothesis was rejected as dehiscence increased after tooth movement through an atrophic alveolar ridge, mainly in the buccal plate.     

Numerical simulation of canine retraction by sliding mechanics.

BACKGROUND: Bone remodeling laws have been used to simulate the movement of a single tooth, but the calculations for simulating the movement of several teeth simultaneously are time-consuming. The purpose of this article is to discuss a method that allows the simulation of more complex tooth movements. METHODS: A 3-dimensional finite element method was used to simulate the orthodontic tooth movement (retraction) of a maxillary canine by sliding mechanics and any associated movement of the anchor teeth. Absorption and apposition of the alveolar bone were produced in proportion to the stress of the periodontal ligament. RESULTS: In a reference case, the canine was retracted by a 2N force with 0.016-in square wire. The frictional coefficient between wire and bracket was 0.2. The movement of both the canine and the anchor teeth could be calculated with the elastic deformation of wire. The canine tipped during the initial unsteady state and then moved bodily during the steady state. It became upright when the orthodontic force was removed. The anchor teeth moved in the steady state and tipped in the mesial direction. The decrease in applied force by friction was about 70%. The tipping of the canine decreased when the wire size was increased or when the applied force was decreased. CONCLUSIONS: Simple assumptions were used in this calculation to simulate orthodontic tooth movements. The calculated results were reasonable in mechanical considerations. This method might enable one to estimate various tooth movements clinically. However, precise comparisons between calculated and clinical results, and the improvement of the calculation model, are left for a future study.     

Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate—Part 2: Relationship between root resorption,horizontal tooth movement,and quantity of grafted autogenous bone

Objective:To evaluate the relationship between external apical root resorption (EARR) of the maxillary central incisors (U1), horizontal orthodontic tooth movement, and quantity of grafted bone in subjects with unilateral cleft lip and palate (UCLP) over an average duration of 8 years.Materials and Methods:Thirty subjects with UCLP were evaluated for EARR of U1 after edgewise treatment (T2). The teeth were classified as having no EARR, moderate EARR (combined into “no/moderate” EARR), or severe EARR. Frontal cephalometric radiographs acquired at eruption of U1 (T0), less than 6 months before secondary alveolar bone grafting (T1), and T2 were evaluated to determine the horizontal inclination (U1-axis angle) and distance of the root apex from the median line (U1-root–VL distance). On the cleft side, the quantities of grafted bone at less than 12 months postsecondary bone grafting and at T2 were evaluated using the alveolar bone graft (ABG) scale.Results:Cleft-adjacent teeth exhibited more severe EARR than did teeth on the noncleft side. The cleft side exhibited greater changes in U1-axis angle and U1-root–VL distance between T0 and T2 than did the noncleft side. On the cleft side, the ABG score at T2 in the severe EARR group was significantly lower than that in the no/moderate EARR group. These measurements were correlated with EARR grade.Conclusions:Cleft-adjacent U1 exhibited more severe EARR than did the U1 on the noncleft side, which might be associated with orthodontic treatment-induced changes in horizontal inclination and root apex movement. On the cleft side, severity of EARR may be correlated with the success of ABG.     

不同时机牙移动对SD大鼠牙槽突裂植骨区骨改建的影响

目的:评价牙移动产生的功能性刺激对SD大鼠牙槽突裂植骨区骨改建的影响,探讨植骨后牙移动的合适时机。方法:选择16只56天的雄性SD大鼠,随机分为4组,按照已建立的外科诱导SD大鼠双侧牙槽突裂模型要求造裂,填塞骨蜡8周后,在双侧裂隙区同时植入大鼠自体髂骨松质骨,左侧为牙移动侧,分别在植骨后即刻、2周、4周、8周近中移动左侧第二磨牙进入植骨区,右侧为对照侧,第二磨牙不进行任何处理。加力牙移动4周后处死动物。通过Micro-CT扫描标本,运用Mimics 10.01软件计算双侧植骨区骨量,采用SAS 9.0软件包对双侧植骨区骨量进行配对t检验,对双侧植骨区骨量的差值进行组间方差分析。结果:各组的牙移动侧植骨区骨量均多于对照侧。0周组牙移动侧与对照侧植骨区骨量差值为0.87mm3,无显著差异(P>0.05);2周组和4周组牙移动侧与对照侧植骨区骨量的差值分别为1.7mm3和1.77mm3,有显著差异(P<0.05);8周组牙移动侧与对照侧植骨区骨量的差值为3.47mm3,有显著差异(P<0.01),8周组两侧植骨区骨量差值的均数与0周组、2周组和4周组均有显著差异(P<0.05)。结论:牙移动对植骨区的功能性刺激能抑制植骨区的骨吸收。植骨8周后的牙移动抑制植骨区移植骨吸收的作用最为明显。     

腭侧错位的上颌侧切牙牙根位置锥形束CT测量分析

目的:通过锥形束CT(CBCT)测量分析上颌腭侧错位的侧切牙牙根位置分布规律,为正畸治疗中此类牙的移动设计提供参考依据.方法:选取符合入选标准伴上颌侧切牙腭侧错位的病例共200例,调取其CBCT,将腭侧错位的上颌侧切牙根长平分8等份,自根尖向牙槽嵴顶方向依次做标记点T1-T8,分别测量各位点的唇侧、腭侧牙槽骨厚度;测量...     

Long-term periodontal status of teeth moved into extraction sites

The present study was undertaken to assess the long-term periodontal status adjacent to teeth that had been moved orthodontically into extraction sites. Twelve persons with a mean age of 29.2 +/- 5.7 (SD) years, who had completed orthodontic therapy at least 10 years previously, were examined. The orthodontic treatment had included bilateral premolar extraction in only the maxilla. Interproximal tooth surfaces in the maxilla adjacent to the extraction sites (study group) were compared to corresponding tooth surfaces in the mandible (control group) with respect to plaque, visual inflammation, bleeding after probing, pocket depth, gingival recession, loss of connective tissue attachment, radiographic bone height, and root resorption. Statistical comparisons were made via analyses of variance and t tests. There were no differences between the groups for any clinical parameter except the presence of less visual inflammation in study subjects. Radiographically, there were no differences in crestal alveolar bone levels measured from the cementoenamel junction. Bone height evaluation by the Bjorn method showed less alveolar support in the study group. However, this was due to the influence of root resorption rather than an effect on crestal height. It was concluded that orthodontic movement of teeth into extraction sites had been without detrimental effect upon the adjacent periodontal status.