Evaluation of impacted maxillary canine position using panoramic radiography and cone beam computed tomography

IntroductionLocalization of impacted maxillary canine (IMC) position is essential in orthodontic treatment for accurate orthodontic treatment as well as prognosis.ObjectivesThis study aimed to: 1- investigate the relationship between the locations of IMC in panoramic radiograph (PR) using sectors in relation to their labio-palatal position in cone beam computed tomography (CBCT): 2- report the incisor root resorption in CBCT in relation to its sector location of IMC in PR.Material and MethodsThe study is a retrospective imaging assessment of 60 IMCs in multiple centers in Riyadh, Saudi Arabia. Sector location of IMC was determined on the PR and correlated with each of their labio-palatal positions and resorption of the root of permanent incisors using CBCT.ResultsThere is a significant correlation between sector location and impaction location of IMC. No statistical correlation was found between IMC sector location and lateral incisor root resorption, whereas a significant correlation was found between sector location and central incisor root resorption.ConclusionsFor Sectors I and II, IMC tended to be in either the mid-alveolus or labial location, whereas Sectors III and IV tended to show palatal impaction. Therefore, sector could be a good tool for localization of IMC and to predict the possibility of incisor root resorption.     

健康成年人上颌牙槽骨骨密度锥形束CT测量分析

目的:探讨锥形束CT(cone beam CT,CBCT)对颌骨细微结构成像、重建及无创性骨量测定的临床可行性,以及运用锥形束CT的Iviewer计算机辅助图像处理软件,对颌骨密度测量的可重复性,为临床牙周病患者诊断、预后及接受种植修复,正畸支抗设计时进行骨量评估提供方法。方法:使用CBCT机在相同条件下投照10名健康成年上颌骨前牙区,在Iviewer软件下进行重建,并由同一研究者测量上颌中切牙牙槽间隔及两侧中切牙与侧切牙牙槽间隔相对骨密度值3次,比较3次测量间有无差异。使用SPSS12.0软件包进行均数间两两比较的方差分析。结果:3个测量区(3个牙槽间隔牙槽骨)相对骨密度均值(VALUEⅠ、VALUEⅡ、VALUEⅢ)3次测量的结果无显著性差异(P>0.05)。结论:CBCT可用于颌骨骨密度的测量,运用CBCT结合图像分析软件技术,可对牙槽骨骨密度进行测量。该方法具有无创性、可重复性,在颌骨局部骨结构的检测方面有临床参考价值。     

应用CBCT回顾分析牙源性上颌窦病变

［摘要］ 目的 通过回顾CBCT资料评估牙源性上颌窦炎的影像学表现及最易引起牙源性上颌窦炎的牙位。方法 将500例CBCT资料分为正常上颌窦、牙源性上颌窦病变、非牙源性上颌窦病变和无法判断来源的上颌窦病变,并进行统计学分析。结果 牙源性上颌窦炎的影像学表现是发生龋病、不良修复体的上颌后牙或对应牙位有未愈合的拔牙创,无论其是否伴有根尖周病变,该病变牙相应上颌窦底黏膜会呈局部隆突性增厚影像。牙源性上颌窦炎发病率占常人的12.4%,占上颌窦病变病人的48.6%。上颌第一磨牙最易引起牙源性上颌窦炎。发生上颌窦炎,即黏膜增厚>2 mm的病例中,黏膜平均增厚(6.11±4.43) mm。结论 牙源性因素占上颌窦炎发病因素的一半;上颌第一磨牙最易引起牙源性上颌窦炎;CBCT能清晰反映上颌窦的解剖解构及上颌窦炎所引起的变化。     

Localization of impacted maxillary canines using cone beam computed tomography. Review of the literature

This review analyzed the literature focused on Cone- Beam Computed Tomography (CBCT) diagnostic accuracy and efficacy in detecting impacted maxillary canines, and evaluated the possible advantages in using CBCT technique compared with traditional radiographs. PubMed and Embase searches were performed selecting papers since 1998 up to September 2011, moreover reference lists were hand searched. Two reviewers selected relevant publications on the basis of predetermined inclusion criteria. The literature search yielded 94 titles, of which 5 were included in the review. Three studies used CBCT technique to 3D localize maxillary impacted canines and assess root resorption of adjacent teeth. Other two publications compared traditional radiographs with CBCT images in the diagnosis of maxillary impacted canines. Only three studies presented the results using statistical analysis. The present review highlighted that the use of CBCT has a potential diagnostic effect and may influence the outcome of treatment when compared with traditional panoramic radiography for the assessment of impacted maxillary canines. Furthermore it underlines the need of future studies performed according with high level methodological standards, investigating diagnostic accuracy and effectiveness of CBCT in the diagnosis of maxillary impacted teeth.     

Anatomical study of the maxillary tuberosity using cone beam computed tomography

Objectives

To examine the dimensions (width, length, and height) of the maxillary tuberosity (MT) and their correlations with age and sex, and to identify different anatomical types for adequate positioning of miniscrews in this area.

Methods

The study enrolled 39 patients attending the University of Valencia. The patients comprised 21 males and 18 females with a mean age of 39.7 ± 8.4 years. The dimensions of all 78 MTs were measured on cone beam computed tomography (CBCT) images using Invivo Dental 5 software.

Results

The intraobserver and interobserver errors were good for all measurements. A total of 858 MT measurements were taken. The widths were greater in men than in women, with significant differences. The MT dimensions showed correlations with patient age, whereby older patients presented with greater widths and lengths, but reduced heights. Three different anatomical types were detected according to patient age.

Conclusions

The dimensions (width, length, and height) of the MT vary according to patient age and sex. The MT dimensions conform to particular anatomical types, which should be taken into account when placing miniscrews in this region.

     

锥形束CT用于评价离体牙槽骨高度准确性的研究

目的评价锥形束CT（CBCT）图像测量离体牙槽骨高度的准确性和可重复性,为其应用于牙周病的临床诊断和预后评价提供理论依据。方法使用CBCT对8具干燥下颌骨进行扫描,在图像上重复测量236个人工选择标志点处牙槽嵴顶至釉牙骨质界的距离;同时使用游标卡尺直接测量以上标志点处牙槽嵴顶至釉牙骨质界的距离。应用SPSS 13.0软件对所得数据进行统计学分析。结果CBCT图像对牙槽嵴顶至釉牙骨质界距离的重复测量结果间差异无统计学意义（P>0.05）;CBCT图像与游标卡尺对牙槽嵴顶至釉牙骨质界距离的测量结果间差异也无统计学意义（P>0.05）。结论CBCT图像可清晰显示牙与牙槽骨之间的空间解剖关系,其对牙槽骨高度体外测量的结果具有准确性和可重复性。     

牙科锥形束CT评价上颌前牙唇面形态对转矩的影响

目的研究上颌前牙的唇面形态及牙冠牙根成角关系对转矩的影响,为临床治疗中调整牙齿的转矩提供参考。方法选择206颗离体上颌前牙为研究对象,其中中切牙77颗、侧切牙68颗、尖牙61颗。利用牙科锥形束CT将全部牙齿进行扫描,在CT工具软件下进行影像的三维重建并提取全部牙的正中矢状切面图像,利用Auto CAD软件测量图像,分别测量牙冠唇面4个不同高度的切线与牙冠长轴所成的角度,以及牙冠长轴与牙根长轴所成的角度（冠根角）。结果当托槽高度为3.5～5.0 mm时,其高度每变化0.5 mm,上颌中切牙转矩变化约为1.5°,上颌侧切牙和尖牙的转矩变化约为2°。上颌中切牙、侧切牙、尖牙冠根角的均数分别为0.88°、3.87°、-3.30°。结论牙体形态的生物学变化从多方面影响矫治后牙齿的转矩角。     

Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography

The purpose of this retrospective radiographic study was to analyze the thickness of the facial bone wall at teeth in the anterior maxilla based on cone beam computed tomography (CBCT) images, since this anatomical structure is important for the selection of an appropriate treatment approach in patients undergoing postextraction implant placement. A total of 125 CBCT scans met the inclusion criteria, resulting in a sample size of 498 teeth. The thickness of the facial bone wall in the respective sagittal scans was measured perpendicular to the long axis of the tooth at two locations: at the crest level (4 mm apical to the cementoenamel junction; MP1) and at the middle of the root (MP2). No existing bone wall was found in 25.7% of all teeth at MP1 and in 10.0% at MP2. The majority of the examined teeth exhibited a thin facial bone wall (< 1 mm; 62.9% at MP1, 80.1% at MP2). A thick bone wall (? 1 mm) was found in only 11.4% of all examined teeth at MP1 and 9.8% at MP2. There was a statistically significant decrease in facial bone wall thickness from the first premolars to the central incisors. The facial bone wall in the crestal area of teeth in the anterior maxilla was either missing or thin in roughly 90.0% of patients. Both a missing and thin facial wall require simultaneous contour augmentation at implant placement because of the well-documented bone resorption that occurs at a thin facial bone wall following tooth extraction. Consequently, radiographic analysis of the facial bone wall using CBCT prior to extraction is recommended for selection of the appropriate treatment approach.     

上颌窦黏膜增厚的锥形束CT影像分析

目的 运用锥形束CT (CBCT)研究牙源性因素对上颌窦黏膜增厚的影响,同时,通过对上颌窦黏膜增厚的随访,研究口腔治疗的作用。方法 回顾性分析2017年8—12月四川大学华西口腔医院就诊的患者,通过CBCT图像筛选出上颌窦最大黏膜厚度>2 mm的患者,评估上颌窦底及上颌窦黏膜增厚与患牙的关系,同时,记录患牙及其治疗的情况,观察随访前后上颌窦黏膜增厚的变化。结果 黏膜厚度与炎症距窦底的距离呈极弱负相关（P<0.05,r=-0.154）,而根尖距窦底的距离与黏膜厚度无直接相关性（P>0.05）。在治疗组中,窦底破坏组的黏膜厚度变化较窦底连续组大,黏膜厚度变化与根尖距窦底的距离呈弱负相关（P<0.01,r=-0.382）,黏膜厚度变化与炎症距窦底的距离呈中等程度负相关（P<0.001,r=-0.524）。结论 上颌窦炎的严重程度可能更大程度上取决于根尖周炎症边缘距窦底的远近而与单纯的根尖位置没有明显的关系。但从治疗效果来讲,炎症病变离上颌窦越近,上颌窦底越易被破坏,上颌窦炎受牙源性因素影响越大,口腔治疗的效果也越好。     

利用锥体束CT对少年期中切牙根尖周牙槽骨厚度的研究

目的　研究少年期中切牙根尖唇舌侧牙槽骨厚度,并探讨与其相关的硬组织测量指标。方法　对42例符合纳入标准的错牙合畸形患者的锥体束CT（CBCT）进行评估,应用MIMICS 10.0软件测量168颗中切牙根尖唇舌侧牙槽骨厚度,并对42例患者进行CBCT三维和头颅侧位片二维头影测量,应用SPSS 21.0统计软件对中切牙根尖周牙槽骨厚度值与8项常用的硬组织头影测量指标进行Spearman 相关性分析。结果　少年期上中切牙根尖唇侧的牙槽骨厚度与上中切牙唇倾度呈正相关,与SNA角呈负相关,腭侧厚度的相关性与唇侧相反;下中切牙根尖唇、舌侧的牙槽骨厚度均与SN-MP角呈负相关,唇侧厚度与ANB角、下中切牙唇倾度呈正相关,腭侧厚度的相关性与唇侧相反。结论　头影测量中部分硬组织测量指标与少年期中切牙根尖周牙槽骨的厚度有相关性,对临床具有参考价值。     

Relationship between maxillary canine intra-alveolar position and maxillary incisor angulation: a cone beam computed tomography study

The aims of the present study were to evaluate the angulation and inclination of permanent maxillary incisors and to correlate the results to the intra-alveolar permanent maxillary canine position during mixed dentition, using cone beam computed tomography (CBCT). The subjects were 30 children aged 7 to 10 years in the inter-transitory period of mixed dentition (permanent incisors and first molars erupted; primary canines, first and second molars erupted; and permanent canines intraosseous). The CBCT scans were obtained and, using the Dolphin Imaging(?) software - version 11.0, 3D images were reconstructed and the measurements were performed. The angulation of the right and left lateral and central maxillary incisors was measured in relation to the sagittal plane and their inclination was measured in relation to the coronal plane. The intra-alveolar height of the right and left maxillary canines was measured from the cusp tip to the axial plane. Pearson's correlation at 5% significance level showed positive correlation between the canine height and the lateral incisor angulation. It was concluded that the intra-alveolar position of the maxillary canines has a direct influence on the angulation of maxillary incisors, especially the lateral incisors.     

青少年患者前牙内收过程中牙槽骨改建情况的锥形束CT研究

目的 通过锥形束CT（CBCT）研究双颌前突的青少年患者前牙内收过程中前牙区牙槽骨改建情况及特点。方法 选取无正畸治疗史双颌前突并且拔除4颗第一前磨牙的青少年患者30例（男12例,女18例,年龄12~18岁）,分别在内收前后1个月拍摄CBCT,测量上下颌每一颗前牙牙根颈1/3、中1/3、尖1/3处唇舌侧牙槽骨厚度,以及上中切牙切缘、牙根颈1/3、中1/3、尖1/3矢状向上内收前后移动的距离,利用SPSS 16.0软件对测量数据进行统计分析。结果 青少年患者上下颌前牙区牙槽骨在前牙内收过程中总体表现为唇侧牙槽骨厚度增加,舌侧牙槽骨厚度减少。其中上颌中切牙根颈1/3及中1/3、上颌侧切牙根颈1/3及尖1/3、下颌中切牙根中1/3、下颌侧切牙根尖1/3、下颌尖牙根中1/3及尖1/3在内收后其牙槽骨厚度表现为增加;上颌尖牙尖1/3、下颌尖牙颈1/3在内收后其牙槽骨厚度表现为减少;其余位点牙槽骨厚度表现为不变。结论 青少年患者前牙内收过程中,前牙发生受控制的倾斜移动,内收后,前牙区牙槽骨总体表现为唇侧牙槽骨厚度增加,舌侧牙槽骨厚度减少。前牙内收后多数位点表现为随牙齿移动牙槽骨厚度增加。     

锥形束CT在治疗上颌前牙区埋伏牙中的应用

目的:探讨锥形束CT(CBCT)在治疗上颌前牙区埋伏牙中的临床应用价值。方法:收集我院2009—2010年经普通X线片确定有埋伏牙,但不易具体定位的患者11例,进行CBCT扫描和三维重建,确定埋伏牙在颌骨内的具体位置。结果:经CBCT扫描、三维重建后,所有患者均可直观再现埋伏牙的形态、数目、在颌骨中的具体位置和发育情况。11例患者共16颗埋伏牙,其中既有埋伏阻生牙又有埋伏多生牙,3例(4颗)为埋伏多生牙,1例有2颗埋伏牙;2例为倒置埋伏,2例为水平埋伏,3例为垂直埋伏,4例为斜位埋伏。根据CBCT结果制订治疗方案,获得满意的治疗效果。结论:CBCT三维重建对于上颌前牙区埋伏牙治疗方案的设计及实施具有重要意义。     

不同垂直骨面型尖牙区牙槽骨形态的锥形束CT研究

目的通过锥形束CT(CBCT)影像学分析,探讨不同垂直骨面型尖牙区牙槽骨形态结构的差异,为正畸临床治疗提供参考。方法选取正畸治疗前病例84例,以FMA角(眶耳平面-下颌平面角)大小为分组标准:FMA>32°为高角型,FMA<22°为低角型,FMA在22°～32°为均角型,通过CBCT获得颅颌面三维影像,测量右侧上下尖牙的牙槽骨高度、厚度及旋转角度,以单因素方差分析和LSD-t检验进行统计学分析。结果上尖牙牙轴与腭侧骨皮质的夹角、上尖牙根尖至腭侧骨皮质的距离、上尖牙旋转角度以及移动距离在三种垂直骨面型中差异有统计学意义(P<0.05),下尖牙牙轴与骨皮质的夹角及距离、下尖牙颊腭侧牙槽骨高度、下尖牙腭侧旋转角度和总旋转角度、下尖牙移动距离在三种垂直骨面型中差异有统计学意义(P<0.05)。结论不同垂直骨面型尖牙区的牙槽骨高度、厚度及旋转角度存在差异。     

锥形束CT灰度值与密度相关性的研究

目的:研究锥形束CT灰度值与体外已知密度参考模型的相关性,并分析锥形束CT不同拍摄条件对密度测量值的影响.方法:将已知密度分别为:1.0、1.5、2.0、2.5 g/cm3的小球固定在模型上,该模型分别放置在直径约为14 cm和16 cm盛满水的圆柱形玻璃烧杯内,并在不同拍摄条件下进行锥形束CT扫描测得小球灰度值.结果...