唇腭裂患者上颌前部牙槽骨厚度及骨开窗、骨开裂的三维评价研究

目的　利用锥形束CT（cone-beam CT,CBCT）评价不同类型唇腭裂患者上颌前部牙槽骨厚度和形态,以及上前牙骨开窗、骨开裂情况。方法　选择016年8月至019年10月间在南京医科大学附属口腔医院就诊拟行口腔正畸治疗的唇腭裂患者85例（男51例,女34例,平均年龄（14.65±4.95）岁）,其中单侧唇裂伴牙槽突裂（unilateral cleft lip and alveolus,UCLA）患者19例,单侧完全性唇腭裂（unilateral complete cleft lip and palate,UCLP）患者5例,双侧完全性唇腭裂（bilateral complete cleft lip and palate,BCLP）患者14例。在正畸治疗开始前均予以拍摄颌面部CBCT,应用Image J软件测量其上前牙唇腭侧牙槽骨厚度（alveolar bone thickness,ABT）,计算骨开窗、骨开裂发生率,并比较不同唇腭裂类型患者上颌前部ABT及上前牙骨开窗、骨开裂发生率的差异。结果　UCLP、UCLA患侧上前牙骨开裂发生率（34.9%、4.9%）显著高于其健侧（10.7%、11.1%）,但骨开窗发生率无统计学差异。UCLP健侧上中切牙（5.9%）、侧切牙（9.7%）骨开裂发生率低于UCLA。UCLA、UCLP、BCLP三组间患侧上前牙骨开裂及骨开窗发生率均无统计学差异。UCLP、UCLA患侧上前牙ABT在多部位小于其健侧。除UCLP/UCLA患侧侧切牙外,UCLA、UCLP、BCLP各类型上前牙唇侧平均ABT均小于腭侧。UCLA、UCLP、BCLP三组间患侧上前牙唇腭侧平均ABT无统计学差异。UCLP患侧上侧切牙、尖牙分别在唇侧和腭侧根颈处ABT大于UCLA。结论　单侧唇腭裂患者患侧上前牙骨开裂发生率高于健侧,ABT则在多部位小于其健侧;而三种类型患者上前牙唇侧ABT均小于其腭侧。单侧唇裂伴牙槽突裂与单侧完全性唇腭裂患者健侧上中切牙、侧切牙骨开裂发生率及患侧侧切牙、尖牙根颈处牙槽骨厚度存在差异;单侧与双侧完全性唇腭裂间上前牙骨开窗、骨开裂发生率及牙槽骨厚度则无差异。     

正畸患者上颌侧切牙和尖牙区骨缺损影响因素的锥形束CT研究

目的: 利用锥形束CT(cone beam computed tomography,CBCT)研究上颌侧切牙和尖牙区骨开裂和骨开窗的危险因素。方法: 实验对象选自2014~2016年就诊于中国医科大学附属口腔医院正畸一科患者治疗前的CBCT,存在骨开裂或骨开窗的上颌侧切牙44例和上颌尖牙43例为实验组,不存在骨开裂和骨开窗的上颌侧切牙43例和上颌尖牙41例为对照组。结果: 牙体倾斜度、牙体长轴与牙槽突长轴的角度、牙槽骨曲度、牙槽骨宽度、牙根宽度与牙槽骨宽度差、牙齿在牙槽骨中的位置有统计学差异(P<0.05),牙根长度、根尖距牙槽骨最凹点的距离无统计学差异(P>0.05)。结论: 牙齿舌倾、牙体长轴与牙槽突长轴角度大、牙槽骨薄、牙槽骨弯曲大、牙齿位置偏离牙槽骨中心(偏唇侧或舌侧)等是上颌侧切牙和尖牙区发生骨开裂与骨开窗的危险因素。     

锥形束CT用于骨性安氏Ⅱ类1分类错(牙合)畸形切牙区唇侧牙槽骨开窗及骨开裂的研究

目的 应用锥形束CT(cone beam computed tomography,CBCT)研究成人骨性安氏Ⅱ类1分类错(牙合)畸形切牙区唇侧牙槽骨开窗及骨开裂的发生率及分布情况,为正畸治疗提供一定参考依据.方法 随机选取2013年7月至2015年5月间北京大学口腔医院正畸科进行锥形束CT扫描的2 376例患者中,临床诊断为骨性安氏Ⅱ类1分类错(牙合)畸形的65例成人患者进行上、下颌切牙区唇侧牙槽骨开窗及骨开裂的统计学分析.结果 在样本人群中,骨开窗和骨开裂的发生率分别为75.38％(49/65)和86.15％(56/65).在不同骨开窗类型中,小于等于根长1/3的骨开窗约占骨开窗总数的76.88％.在不同骨开裂类型中,范围在2～4 mm的最多,约占骨开裂总数的77.13％.在样本牙齿中,切牙区唇侧牙槽骨开窗的发生率为30.78％,以左上颌侧切牙最高(7.69％),右上颌侧切牙次之(6.92％),右上颌中切牙最低(1.15％);切牙区唇侧牙槽骨开裂的发生率为36.15％,右下颌中切牙最高(9.62％),左下颌中切牙次之(8.27％),下颌的发生率高于上颌.男性与女性切牙唇侧骨开窗与骨开裂的发生率无显著性差异.结论 骨性Ⅱ类1分类错(牙合)患者中,切牙区唇侧牙槽骨开窗和骨开裂的发生率较高,且多数骨开窗范围小于等于根长1/3,骨开裂在2～4 mm之间.     

减数正畸治疗中中切牙牙根及牙槽骨形态变化的锥形束CT测量分析

目的： 研究减数正畸治疗对成人患者中切牙牙根吸收及牙槽骨形态的影响。方法： 选取11例行减数正畸治疗的成年患者,于治疗前、后进行全牙列锥形束CT（CBCT）检查,观察治疗前、后上、下中切牙牙根吸收、牙槽骨厚度变化与牙槽骨高度缺损,采用SPSS 23.0软件包对数据进行统计学分析。结果： 部分牙位出现牙长度减小及牙根长度减小,上颌切牙牙根长度变化量大于下颌切牙。中切牙舌腭侧颈部牙槽骨宽度表现为一定程度降低,其中上中切牙腭侧根颈部及下颌中切牙舌侧根中部牙槽骨宽度变化较为明显。下颌中切牙唇侧中部牙槽骨宽度增加,但舌腭侧牙槽骨在正畸治疗后骨开窗、骨开裂位点增多,且较上颌更明显。结论： 减数正畸治疗伴随中切牙牙根一定程度上的吸收和舌腭侧牙槽骨吸收,唇侧牙槽骨骨量增加。下颌舌侧牙槽骨吸收导致骨开窗、骨开裂位点增多。     

单侧完全性唇腭裂患者前牙区牙槽骨开窗、骨开裂的锥形束CT研究

目的 利用锥形束CT（cone-beam CT,CBCT）研究单侧完全性唇腭裂（unilateral cleft lip and palate,UCLP）患者前牙区牙槽骨开窗、骨开裂的发生率。方法 选取2014年6月—2017年9月就诊于中南大学湘雅二医院的UCLP患者42例（男25例,女17例）。匹配性别和年龄,纳入42例骨性Ⅲ类非唇腭裂患者为对照组。利用CBCT评估UCLP组与对照组前牙区骨开窗和骨开裂的发生率,采用SPSS 22.0软件包对数据进行统计学分析。结果 裂隙侧、非裂隙侧及对照组前牙骨开裂发生率分别为50.88%、42.39%和28.77%。UCLP组裂隙侧上颌前牙同名牙骨开裂的发生率均显著高于对照组（P<0.05）,非裂隙侧上颌侧切牙骨开裂的发生率显著高于对照组（P<0.05）,裂隙侧上颌中切牙骨开裂发生率显著高于非裂隙侧（P<0.05）。裂隙侧、非裂隙侧与对照组前牙区骨开裂均好发于唇侧。骨开窗的发生率在裂隙侧、非裂隙侧及对照组间无显著差异（P>0.05）。结论 在UCLP患者中,牙槽骨开窗和骨开裂较常见,临床治疗中应引起重视。     

上颌切牙内收前后牙根及牙槽骨的变化

目的 通过锥形束CT（CBCT）测量并分析上颌前突患者上颌切牙内收治疗前后牙根及牙槽骨的变化。方法 选取2014年1月—2015年12月完成的正畸病例37例,其中男性17例,女性20例,平均14.5岁。所有患者拔除上颌双侧第一前磨牙且使用种植钉强支抗内收上颌切牙,通过头影测量获取上颌切牙内收角度、内收量及伸长量,使用NewTom NNT软件对CBCT数据进行多平面重建,调整冠状、轴向与矢状轴,选取通过切缘和根尖的牙齿长轴最长的矢状截面测量上颌切牙内收治疗前后牙根及牙槽骨的变化。结果 上颌前牙内收治疗前后,中切牙内收角度为12.92°±6.43°,内收量为（5.54±2.21） mm,伸长量为（0.60±0.95） mm,牙根吸收长度为（0.81±0.46） mm,牙根吸收率为6.80%±3.60%,切牙内收治疗前后牙根长度变化具有统计学差异（P<0.05）,治疗后唇侧牙槽骨高度降低量为（0.20±0.22）mm,治疗前后差异有统计学意义（P<0.05）。牙根吸收率与上颌中切牙切端的水平向位移及根尖至唇侧皮质骨的距离具有相关性;唇侧牙槽骨高度变化量与上颌切牙内收角度的相关系数为0.354,具有统计学意义（P<0.05）。结论 上颌前突患者代偿性治疗后,上颌切牙产生了明显的牙根吸收,唇侧牙槽骨高度降低。牙齿移动量越大,或超出了牙槽骨的解剖限制和改建限度,容易导致牙根吸收。唇侧牙槽骨高度变化量与切牙内收角度呈负相关。     

上颌前牙牙槽骨骨皮质切开辅助治疗轻度骨性Ⅱ类错牙合畸形的临床观察

目的：探讨骨皮质切开术辅助治疗轻度骨性Ⅱ类错(牙合)正畸的效果。方法：对7名骨皮质切开术辅助治疗的轻度骨性Ⅱ类1分类错(牙合)成人患者矫治前后的 CBCT 进行三维测量分析。结果：骨皮质切开的患者前牙内收时间为3．2个月;上中切牙明显内收,上颌牙槽骨也有内收,随着上颌切牙的内收上唇内收明显。结论：骨皮质切开术辅助矫治骨性Ⅱ类错(牙合)成人患者能够加速牙齿移动,并尽可能地实现前牙的整体内收,改善了患者软组织侧貌。     

双颌前突患者拔牙内收后前牙区牙槽骨改建的CBCT研究

目的 研究双颌前突患者前牙内收后牙槽骨的形态变化,以了解牙齿的安全移动限度。方法 选取31例安氏Ι类双颌前突患者,在正畸治疗前后拍摄CBCT图像,测量牙槽骨厚度及高度并进行统计学分析。结果 上前牙内收后,除了侧切牙及尖牙根中1/2外,其余唇侧位点牙槽骨厚度均增加;腭侧牙槽骨厚度及高度均有不同程度降低;腭侧骨开裂率均增高,上侧切牙唇侧骨开窗率降低。结论 双颌前突患者正畸治疗后唇侧牙槽骨有一定的增生,腭侧牙槽骨明显吸收,牙槽骨改建能力有限,提示我们在正畸治疗前需明确牙槽骨的结构特点及牙根位于牙槽骨中的位置,避免医源性骨缺损的发生。     

成人前牙内收前后切牙牙槽骨高度变化的研究

目的：研究成人双颌前突患者前牙内收前后切牙区唇侧、舌侧牙槽骨高度的变化。方法：选取双颌前突成人患者15例，治疗需拔除4颗第一前磨牙行前牙内收，内收前后分别拍摄 CBCT 片，对其上、下颌8颗切牙唇舌侧牙槽骨高度进行测量和对比分析。结果：上、下颌切牙内收后唇侧牙槽骨高度均有不同程度升高，以下颌更为显著（P ＜0．05），舌侧牙槽骨高度降低（P ＜0．05）。结论：成人双颌前突患者切牙行大范围舌向移动时舌侧牙槽骨高度降低，临床治疗中应予以关注。     

成人双颌前突患者正畸前后上颌切牙区唇腭侧牙槽骨的变化

目的:分析成人双颌前突患者治疗前后上颌切牙区唇腭侧牙槽骨的变化,为正畸治疗中在牙槽骨内的安全移动牙齿提供参考依据.方法:纳入23例成人双颌前突的患者,拔除4颗第一前磨牙,采用直丝弓矫治技术一步法整体内收上下前牙.患者治疗前后均拍摄锥体束CT片,测量上颌切牙区唇腭侧牙槽骨厚度(alveolar bone thickness,ABT)、釉牙骨质界-牙槽嵴顶的高度(alveolar bone height,ABH)和牙槽骨面积(alveolar bone area,ABA).结果:治疗后上颌切牙区唇侧的ABT在根中和根尖部水平显著升高,而腭侧的ABT在颈部、根中和根尖3个水平上均下降(P<0.05);中切牙在颈部和根中两个水平上总ABT显著减少(P<0.05),而侧切牙在颈部、根中和根尖处总ABT均减少(P<0.05);正畸治疗后,切牙区腭侧ABA减少,而唇侧ABA增加(P<0.05);上颌中切牙和侧切牙腭侧的ABH和上颌侧切牙唇侧的ABH显著增加(P<0.01).结论:正畸治疗会导致成人双颌前突患者的切牙区腭侧的牙槽骨发生显著吸收,减少整个切牙区的牙槽骨量,需关注其对牙周组织的长期影响.     

Geometric analysis of alveolar bone around the incisors after anterior retraction following premolar extraction

Objective:To evaluate changes in shape and alterations in thickness and vertical marginal bone levels of the alveolar bone around the maxillary and mandibular incisors before and after orthodontic treatment with premolar extraction using geometric morphometric analysis.Materials and Methods:Thirty-six patients with Class I bialveolar protrusion who underwent orthodontic treatment with premolar extraction were included. Cone-beam computed tomographic scans were obtained from the patients before and after treatment. Five fixed landmarks and 70 semilandmarks were used to represent the morphology of the alveolar bone around the maxillary and mandibular incisors. The coordinates of the landmarks of the alveolar bones were generated by Procrustes fit. The labial and lingual alveolar bone thicknesses around the maxillary and mandibular incisors and vertical marginal bone level were assessed quantitatively.Results:There was a significant difference in shape change of the alveolar bone before and after treatment. The deformation grid of the thin plate spline showed that the thickness and vertical marginal bone decreased on the lingual side after treatment. Shape changes were greater for the lingual alveolar bone on the mandibular incisor than for the maxillary incisors.Conclusions:Orthodontic treatment with premolar extraction might cause loss of alveolar bone around the maxillary and mandibular incisors. Careful consideration is needed to avoid iatrogenic degeneration of periodontal support around the incisors, particularly in the lingual area.     

骨性安氏II类1分类成年患者拔牙矫治前后牙周表型的评估分析

目的　分析不同牙周表型的骨性安氏II类1分类成年患者拔牙矫治后上切牙区唇侧骨开裂、骨开窗及牙根吸收情况。方法　研究纳入24例骨性安氏II类1分类成年患者，通过术前CBCT和数字化印模数据的重叠，对前牙牙龈厚度进行无创的定量测量。根据术前上中切牙牙龈厚度将研究对象分为薄龈生物型组（牙龈厚度<1.5mm）和厚龈生物型组（牙龈厚度≥1.5mm）。使用CBCT测量正畸治疗前后上切牙唇侧牙槽骨骨开裂、骨开窗及牙根吸收的程度。结果　骨性安氏II类1分类成年患者术前骨开裂和骨开窗的发生率为31.2%和18.8%，经拔牙正畸治疗后增加至75%和20.8%。薄龈生物型组术后上前牙唇侧牙槽嵴顶至釉牙骨质界距离为3.19 ± 0.43mm，显著高于厚龈生物型组（2.16 ± 0.11mm），但该距离与牙龈厚度无显著相关性（r= -0.1108，P= 0.6146）。牙根吸收程度和牙龈厚度呈正相关（r=0.4223，P=0.0447），且厚龈生物型组牙根吸收量为2.24 ± 1.24mm，显著高于薄龈生物型组（1.08 ± 0.73mm）。结论　骨性安氏II类1分类成年患者经拔牙正畸治疗后上切牙区唇侧牙槽骨骨开窗、骨开裂及牙根吸收均加重，其中薄龈生物型组垂直牙槽骨吸收风险较大，厚龈生物型组骨开窗及牙根吸收风险较大。     

Alveolar bone changes in maxillary and mandibular anterior teeth during orthodontic treatment: A systematic review and meta-analysis

The association between tooth movement and remodelling of surrounding bone is controversial. To analyse the effect of tooth movement on alveolar bone changes in maxillary and mandibular anterior teeth by cone-beam computed tomography (CBCT). The Embase, Cochrane Library and Medline databases were searched without any language restrictions. Longitudinal studies using CBCT to observe alveolar bone changes of maxillary and mandibular anterior teeth during orthodontic treatment were included. Two independent reviewers performed the study selection, data extraction and methodological quality assessment. A total of 26 studies were included in this review, 14 of which were eligible for quantitative synthesis. In extraction cases, meta-analysis showed vertical bone loss on the labial (0.36 mm) and lingual (0.94 mm) sides of maxillary incisors, and lingual bone thickness decreased significantly at the cervical level (0.57 mm). In non-extraction cases, vertical alveolar bone loss was significant on the labial side (0.97 mm) and lingual side (0.86 mm) of mandibular incisors. Subgroup analysis for skeletal class III patients indicated that vertical alveolar bone loss was 1.16 mm on the labial side and 0.83 mm on the lingual side of mandibular incisors. The absence of high-quality studies and the high heterogeneity of the included studies were limitations of this systematic review and meta-analysis. Based on limited evidence, alveolar bone height and thickness, especially at the cervical level, decreased during both labial and lingual movement of anterior teeth.     

Labially impacted maxillary canines causing severe root resorption of maxillary central incisors

This is a case report of a patient with bilateral labial impaction of maxillary canines causing pressure resorption on the lateral aspects of the maxillary central incisors. The orthodontic treatment plan included extraction of the impacted canines, positioned between the central and the lateral incisors. Six years after the orthodontic treatment, the affected central incisors remained asymptomatic.     

Changes in alveolar bone thickness due to retraction of anterior teeth.

In cases of bimaxillary protrusion, extraction of 4 premolars and orthodontic treatment with retraction of the anterior teeth is a widely used approach. However, there is controversy over whether the changes that occur in the anterior alveolar bone always follow the direction and quantity of tooth movement. Nineteen patients with dentoalveolar bimaxillary protrusion treated by extracting the 4 first premolars were evaluated with lateral cephalograms and computed tomography (CT). Cephalograms and CT scans were made before treatment and 3 months after retraction of the incisors. The measurements of the cephalograms showed that maxillary and mandibular incisors were retracted primarily by controlled tipping of the teeth. For all maxillary and mandibular incisors, we assessed the labial and the lingual alveolar plates at crest level (S1), midroot level (S2), and apical level (S3) for bone-thickness changes during retraction of the maxillary and mandibular anterior segments. In the mandibular arch, the labial bone maintained its original thickness, except the S1 measurements, which showed a significant decrease in bone thickness (P <.001). In the maxillary arch, the labial bone thickness remained unchanged. There were statistically significant decreases in lingual bone width in both arches after retracting the incisors. Some of the patients demonstrated bone dehiscence that was not visible macroscopically or cephalometrically. When tooth movement is limited, forcing the tooth against the cortical bone may cause adverse sequelae. This type of approach must be carefully monitored to avoid negative iatrogenic effects.     

Extreme dentoalveolar compensation in the treatment of Class III malocclusion

The orthodontic treatment of an adult patient with a skeletal Class III malocclusion, increased anterior facial height, negative overjet, and bilateral posterior crossbite is presented. Treatment options included mandibular first premolar or third molar extractions with dentoalveolar compensation or combined surgical-orthodontic treatment. Mandibular third molar extraction with dentoalveolar compensation was the treatment choice. Biofunctional brackets, with accentuated lingual crown torque on the maxillary incisors and accentuated buccal crown torque on the mandibular incisors, were used. The anterior crossbite was corrected with intermaxillary elastics from the palatal aspect of the maxillary incisors to the labial aspect of the mandibular incisors. Class III elastics moved the maxillary teeth mesially and assisted in retruding the mandibular teeth. Patient compliance with the elastics was excellent, and satisfactory dentofacial esthetics were achieved. This treatment protocol has rigorous indications, and it is not a routine plan. The mechanotherapy and the pros and cons of this approach are discussed.     

下颌中切牙唇倾度与牙槽骨厚度关系的锥形束CT分析

目的应用锥形束CT（CBCT）测量分析下颌中切牙不同唇倾度与牙槽骨厚度的关系。方法选择60例患者的头颅侧位片和CBCT影像资料,按照下颌中切牙-下颌平面角（L1-MP）分为3组,即舌倾组L1-MP<85.6°;正常组L1-MP为85.6°~99.6°;唇倾组L1-MP>99.6°。三维重建CBCT,在矢状面图像上沿下颌中切牙长轴,选择牙槽骨截面最大的图像,将牙根从釉牙骨质界到根尖点平均分为4段,测量唇、舌侧牙槽骨厚度并合计得到总厚度,观察计数骨开窗及骨开裂发生情况。采用SPSS17.0软件包对数据进行统计学分析。结果舌侧及总牙槽骨厚度在各测量位点间的差异均有统计学意义。根中1/2、根尖1/4及根尖处牙槽骨厚度唇侧均小于舌侧。舌侧牙槽骨厚度在各测量位点均为舌倾组小于唇倾组, 牙槽骨总厚度在根尖、根尖1/4、根中1/2处舌倾组比唇倾组薄。唇倾组和舌倾组的骨开裂发生率均高于正常组,差异显著(P<0.05)。结论下颌中切牙舌侧及总牙槽骨厚度从根尖区到根颈区逐渐变小,舌倾组舌侧及牙槽骨总厚度比唇倾组薄,下颌中切牙牙轴过度唇倾或舌倾易发生骨开裂。     

Treatment of dentoskeletal bimaxillary protrusion: additional extraction of maxillary second molars

This case report describes the orthodontic treatment of an 18-year-old female patient with Class II malocclusion with dentoskeletal bimaxillary protrusion. An acceptable treatment result was obtained with a four first premolar extraction and an additional maxillary two second molar extraction plan. Standard edgewise appliances were placed after the premolars were extracted. A positive soft tissue response to treatment was achieved, and the patient’s profile was improved, with a reduction of lip protrusion and mentalis strain. Dentally, the interincisal angle improved significantly as both the maxillary and mandibular incisors were uprighted after space closure. The occlusion remained stable during 2 years of follow-up.