全景片及CBCT对不同前磨牙拔除模式上颌中切牙根吸收的诊断研究

目的　采用全景片及CBCT测量不同前磨牙拔除模式对上中切牙根吸收的影响。方法　正畸患者27例分为3组：T0（不拔牙组）、T1（拔除第一前磨牙组）和T2组（第二前磨牙组）,所有患者治疗前后均拍摄全景片和CBCT,对各组上切牙根吸收进行测量。结果　3组患者正畸治疗后均出现不同程度的牙根吸收现象。CBCT测量显示,T1和T2组的中切牙牙根吸收较T0组显著。而T1组的根吸收量大于T2组(P < 0.05);全景片测量表明,T0组和T2组根吸收差异不显著,T1组的根吸收量大于T0组。CBCT与全景片测量比较,T1和T2组差异无显著性,T0组差异有显著性。结论　不同的拔牙模式会对上切牙的根吸收产生不同的影响。CBCT测量的灵敏度要大于全景片。     

传统全景片和锥形束CT重建全景片测量牙轴近远中倾斜度的对比研究

目的 比较传统全景片和锥形束CT（CBCT）重建全景片用于测量牙轴近远中倾斜度的准确性。方法 收集15名个别正常志愿者的石膏模型,在模型上确定上下颌从左侧第一磨牙到右侧第一磨牙的牙体长轴和平面的标记点,制作放射显影装置,志愿者佩戴放射显影装置拍摄全景片和 CBCT片。分别在石膏模型、全景片和 CBCT重建全景片上测量牙轴近远中倾斜度。利用多元方差分析和 Dunnett-t检验比较3种测量方法的差异。结果 3种测量方法间的差异有统计学意义（P=0.00）。与模型测量相比,全景片组中12个牙位有2个牙位（上下颌第二前磨牙）测量结果的差异有统计学意义（P=0.00）,CBCT组12个牙位的差异均无统计学意义。结论 评价牙轴近远中倾斜度时,传统全景片存在一定误差, CBCT重建全景片是一种更为有效的评价手段。     

全景片与锥形束CT对诊断AngleⅡ~2错牙合畸形颞下颌关节改变的研究

目的比较全景片和锥形束CT(CBCT)对AngleⅡ~2错牙合畸形患者的髁突骨质改变检测的准确性,为临床合理运用X线片进行诊断提供依据。方法 60例AngleⅡ~2错牙合畸形患者根据临床检查分为有症状组(A组)和无症状组(B组),分别对双侧颞下颌关节进行全景片和CBCT检查,对髁突骨质改变进行检测,并对二者差异进行统计学分析。结果 CBCT对髁突骨质改变的诊断一致性较高,全景片一致性诊断存在一定差异;以CBCT对髁突骨质改变的检测结果为金标准,该两组与CBCT检测结果比较,A组全景片正确诊断率为66.7%,B组全景片正确诊断率为85.7%。结论全景片在筛选AngleⅡ~2错牙合畸形患者TMD的临床诊断中具有一定的应用价值,但其灵敏度低于CBCT。     

锥形束CT在上颌埋伏中切牙诊断中的应用

目的:探讨锥形束CT(CBCT)在上颌埋伏中切牙诊断中的作用。方法:选择正畸临床33例上颌中切牙埋伏阻生患者作为研究对象,拍摄全景片和CBCT,由10位正畸医生对33例埋伏牙患者的全景片和CBCT分别进行测量、分析,填写研究表格。所得数据用SPSS 17.0软件,采用McNemar检验、Kappa检验和配对t检验进行统计学分析。结果:CBCT与全景片对埋伏牙是否弯根、近中切角距中线距离和有无多生牙等分析项目没有统计学差异,其余分析项目均有统计学差异。结论:对上颌埋伏中切牙诊断,CBCT更直观、三维测量更精确,更好地指导临床。     

全景及根尖片对正畸相关牙根吸收诊断准确性的研究

目的以CBCT对样本牙根吸收的诊断结果为金标准,检验全景片（OPG）及根尖片对正畸相关牙根吸收（RRAOF）定性及分级半定量诊断结果的准确性。方法纳入完成固定正畸治疗的32例患者的121颗上前牙,正畸治疗前后均拍摄OPG、上前牙根尖片、上前牙CBCT。由3名放射专科医生按照Levander and Malmgren分度法对纳入样本的3种图像的牙根吸收程度分别进行评估,并以CBCT的诊断结果为金标准,检验OPG及根尖片对相同样本牙根吸收定性及分级半定量诊断结果的准确性。结果OPG、根尖片对相同样本RRAOF的定性及分级半定量诊断结果,与CBCT相比较均存在统计学差异（P<0.05）。根尖片和OPG对RRAOF定性诊断的敏感性分别为71.6%和78.4%,特异性分别为25.5%和51.1%,准确度分别为53.7%和67.8%。结论根尖片与OPG对正畸相关牙根吸收的诊断准确性较差。     

锥形束CT在牙体牙髓病诊治中的研究进展

口腔颌面锥形束CT（CBCT）是近10余年开始应用于临床的一种新型影像学检查方法,因其检查时间短、空间分辨率高、放射剂量低、无图像失真、价格适中等优点,在口腔疾病诊治中得到广泛应用。随着技术的发展,CBCT检查在观察根尖周病变、根管治疗、诊断根管穿孔、观察牙根吸收及诊断根折等方面的优势逐渐显示出来。本文就CBCT在牙体牙髓病诊治方面的最新研究进展做一综述。     

数字化配准法测量种植体植入精度分析

目的 ：建立一种新的数字化配准法，测量种植体植入精度，并与传统锥体束CT(CBCT)进行对比。方法 ：根据纳入和排除标准，纳入24例患者的36颗种植体作为研究对象，分别采用传统CBCT法和数字化配准法对种植体植入精度进行测量分析。测量参数为种植体颈部偏差(d1)、根尖部偏差(d2)和角度偏差(α)。采用SPSS 19.0软件包对数据进行统计学分析。结果：传统CBCT法测量精度为种植体颈部（0.88±0.64） mm，种植体根尖部（1.07±0.85） mm，角度（4.74±2.35）°；数字化配准法测量的精度为种植体颈部（0.86±0.67） mm，种植体根尖部（1.12±0.88） mm，角度（4.56±2.66）°；两者之间无统计学差异（P>0.05）。结论：数字化配准法的测量精度与传统CBCT无显著差异，可用于临床实践。     

下颌管及其分支与下颌第三磨牙关系的影像学观察

目的:利用椎形束CT(CBCT)及全景片观察下颌管及其分支在下颌第三磨牙区域的情况。方法 :对179名患者的216颗第三磨牙进行CBCT及全景片检查。在全景片及CBCT上观察下颌管及其分支在第三磨牙区域走向及与第三磨牙的关系。结果:全景片上观察到有4例下颌管有分支,CBCT观察到有22例有分支;下颌管分支与第三磨牙的关系:A类有8例,B类有6例,C类有2例,D类有6例,其中,分支位于第三磨牙颊侧的有7例,舌侧的有6例,位于第三磨牙牙根下方的有9例。结论:利用CBCT可以对下颌管及下颌第三磨牙的空间位置进行更好地观察。CBCT对下颌管分支有更高的检出率。     

下颌阻生第三磨牙拔除术邻牙损伤风险及预防

目的提出一种基于影像学的下颌阻生第三磨牙邻牙损伤风险分级方法,以预测风险和指导手术。方法从接受全景片检查者中筛选出与邻牙接触的下颌阻生第三磨牙连续病例的1359颗牙作为样本,进行评分：埋伏深度评分,高、中、低位阻生牙分别计1、2、3分;与邻牙接触面积评分,将该面积占牙冠的比例≤1/3（少）、>1/3~≤2/3（中等）、>2/3（多）分别计1、2、3分。将得分之和=3设为I级（低度）风险,得分之和=4设为Ⅱ级（中度）风险,得分之和≥5设为Ⅲ级（高度）风险。对样本中有锥形束CT（CBCT）检查者以相同标准行风险等级评价,用Kappa值和youden指数比较2种影像评价结果。用K-W检验分析阻生牙埋伏深度、与邻牙接触面积及阻生方向与邻牙损伤风险的相关性。采用SAS 8.2软件包对数据进行统计学分析。结果与邻牙接触的阻生牙占96.25%（1359/1412）,其中Ⅰ、Ⅱ、Ⅲ级风险分别占17.88%、13.63%和4.86%。72颗阻生牙CBCT和全景片评价接触面积的Kappa值为0.7844;以CBCT为金标准,全景片评价与邻牙接触少、中等、多的youden指数分别为0.8889、0.6781和0.5560。水平阻生者出现高风险的比例较高（P<0.01）。结论该分级从阻生牙埋伏深度及与邻牙接触面积两方面较全面地反映和预测了邻牙损伤风险。全景片可用于该风险分级, CBCT可作为补充     

锥形束CT用于诊断复杂根尖周病价值研究

目的    评价锥形束CT（CBCT）检查对根尖周病复杂病例的诊断价值 。方法    于2013 年5月至2014年5月从沈阳市铁西区牙病防治所门诊随机选取以不明原因牙痛为主诉的患者40例（患牙40颗）,拍摄患牙X线根尖片（常规正位和远中10°平行投照）并进行CBCT检查,采用根尖周指数（PAI）评价根尖周病损状况,比较两种方法对根尖周病复杂病例诊断及病因判断的差异。结果    X线根尖片与CBCT检查在判断患牙有无根尖周病损上一致性差;两种方法对患牙PAI 分级判断的一致性亦差;CBCT检查能够更好地明确牙痛原因。结论    CBCT 检查有助于诊断临床上不明病因的根尖周病复杂病例。     

Comparison of cone-beam computed tomography and periapical radiography for detecting simulated apical root resorption

Objective:To compare the diagnostic accuracy between cone-beam computed tomography (CBCT) and periapical radiography for detecting simulated external apical root resorption (EARR) in vitro.Materials and Methods:The study sample consisted of 160 single-rooted premolar teeth for simulating EARR of varying degrees according to four setups: no (intact teeth), mild (cavity of 1.0 mm in diameter and depth on root surface), moderate (0.4 mm, 0.8 mm, 1.2 mm, and 1.6 mm root shortening), and severe (2.4 mm, 2.8 mm, 3.2 mm, and 3.6 mm root shortening). Two groups of radiographic images were obtained via CBCT and periapical radiography. The absence or presence and the severity for all resorption lesions were evaluated blindly by two calibrated observers.Results:With the CBCT method, the rates of correct classification of no, mild, moderate, and severe EARR were 96.3%, 98.8%, 41.3%, and 87.5%, respectively; with the periapical radiography method, the rates were 82.5%, 41.3%, 68.8%, and 92.5%, respectively. Highly significant differences were found between the two imaging methods for detection of mild (P < .001), moderate (P < .001), and all EARR (P < .001). For detection of all EARR, the sensitivity and specificity values were 75.8% and 96.3% for CBCT, compared with 67.5% and 82.5% for periapical radiography.Conclusion:CBCT is a reliable diagnostic tool to detect simulated EARR, whereas periapical radiography underestimates it. However, if a periapical radiograph is already available to the diagnosis of EARR, CBCT should be used with extreme caution to avoid additional radiation exposure.     

Detection of vertical root fractures by conventional radiographic examination and cone beam computed tomography – an in vitro analysis

Abstract – Objectives: This study compared the ability of conventional radiographic and cone beam computed tomography (CBCT) examinations to detect vertical root fractures (VRF) in teeth with or without root canal treatment and metallic posts. Furthermore, the influence of using different voxel sizes from CBCT images was assessed. Methodology: Sixty single‐rooted human teeth were randomly divided into two groups: experimental and control. Twenty teeth were endodontically prepared and obturated with gutta‐percha, twenty had a metallic postcemented after the filling, and twenty had no preparation. The teeth from the experimental group were fractured. All teeth were radiographed with three different horizontal angles, and after, CBCT images were acquired following three protocols in which the variation was the voxel resolution (0.4, 0.3, and 0.2 mm). Three calibrated examiners assessed the images. Results: Chi‐squared test showed no statistical difference among the images in detecting VRFs. The results of the diagnostic performance tests presented similar ability to detect VRFs when conventional radiographic examination was compared with 0.2 and 0.3‐voxel CBCTs scans, in roots without endodontic treatment and metallic post. Moreover, specificity, sensitivity, and accuracy findings were similar for both 0.2 and 0.3‐voxel resolution scans for teeth that are not root filled. However, it was observed that in teeth with root canal treatment and a post, the accuracy was higher when 0.2‐mm voxel resolution was used. Conclusion: The radiographic examination with horizontal angle variation should be encouraged as the first complementary approach to assess the presence of VRFs. If conventional imaging is not capable to provide adequate information, CBCT can be indicated if a root fracture is strongly suspected. The root condition should then guide the voxel resolution choice, selecting 0.3‐voxel for not root filled teeth and 0.2‐voxel for teeth with filling and/or a post.     

Influence of voxel size on the diagnostic ability of cone-beam computed tomography to evaluate simulated root perforations

Objectives

This study aimed to assess the use of different voxel sizes of a cone-beam computed tomography (CBCT) unit for detecting root perforations of different sizes and locations ex vivo and to compare the diagnostic possibilities of CBCT with those of periapical radiography (PR).

Methods

The study included 36 recently extracted intact human mandibular one-rooted teeth with developed apices. Root perforations of 0.2, 0.3, or 0.4 mm in diameter were drilled on the buccal and lingual sides at the cervical, middle, and apical thirds. A total of 216 portions were obtained. One tooth at a time was placed in a dry human mandible in an artificially created alveolus. Cross-sectional CBCT images were obtained using voxel resolutions of 0.4, 0.3, 0.25, and 0.2 mm. PRs were obtained using the paralleling technique in three directions in the horizontal plane: direct view, mesial angulation, and distal angulation with a 20° angle.

Results

There were no significant differences in sensitivity between 0.4/0.3 and 0.25/0.2-mm voxel resolutions. Significant differences were found between voxel sizes of 0.4/0.25, 0.4/0.2, 0.3/0.25, and 0.3/0.2 mm. The observers failed to diagnose any of the perforations using PR.

Conclusions

CBCT is a reliable imaging system for detecting root perforations that are not detectable with PR. A 0.2-mm voxel resolution was the best choice for diagnostic use in this study. Neither perforation location nor size influenced the diagnostic abilities of CBCT, except that it was harder to detect a root perforation in the apical part of the root.     

Influence of Voxel Size in the Diagnostic Ability of Cone Beam Tomography to Evaluate Simulated External Root Resorption

This study assessed in vitro the diagnostic ability of cone beam computed tomography (CBCT) scans with different voxel resolutions in the detection of simulated external root resorption (ERR). For that purpose, 59 teeth were viewed through iCAT tomography (Imaging Sciences International, Inc, Hatfield, PA) following three protocols in which the variation was the voxel resolution (0.4, 0.3, and 0.2mm). A calibrated examiner blinded to the protocol assessed the images through the i-CAT View software (Imaging Sciences International, Inc). The chi-square statistical analysis did not show associations between voxel resolution, section plane, size of cavity, and radicular third. Sensitivity and specificity values were similar. However, likelihood ratio values of 6.4 for a 0.4-mm voxel, 16 for a 0.3-mm voxel, and 12 for a 0.2-mm voxel were found. It was concluded that CBCT is a reliable method for the investigation of simulated ERR, and a 0.3-mm voxel appeared to be the best protocol, associating good diagnostic performance with lower X-ray exposure.     

锥形束CT诊断根管纵裂临床价值研究

目的 通过体外模型对比研究锥形束CT和根尖片对根管纵裂的诊断价值。方法 收集2010—2011年郑州大学口腔医学院和肇庆市口腔医院因正畸或牙周病拔除的健康离体单根牙60颗,根管预备充填后,去除根充材料,再用根管钉用轻力使40颗牙根纵裂：20颗完全型牙根纵裂、20颗不完全型牙根纵裂;其余20颗完整牙根为对照。按正常牙位排列置于石膏模型上,分别用根尖片和锥形束CT扫描,阅片后作出诊断。结果 根尖片与CBCT诊断根管纵裂的敏感度差异有统计学意义（P < 0.05）。CBCT诊断根管治疗后完全型牙根纵裂和不完全型牙根纵裂的差异无统计学意义（P > 0.05）。结论 CBCT比根尖片诊断根管治疗后牙根纵裂的敏感度高,临床上可用CBCT辅助诊断早期牙根纵裂。     

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目的通过体外模型对比研究锥形柬CT和根尖片对根管纵裂的诊断价值。方法收集2010—2011年郑州大学口腔医学院和肇庆市口腔医院因正畸或牙周病拔除的健康离体单根牙60颗,根管预备充填后,去除根充材料,再用根管钉用轻力使40颗牙根纵裂：20颗完全型牙根纵裂、20颗不完全型牙根纵裂;其余20颗完整牙根为对照。按正常牙位排列置于石膏模型上,分别用根尖片和锥形束CT扫描,阅片后作出诊断。结果根尖片与CBCT诊断根管纵裂的敏感度差异有统计学意义（P〈0．05）。CBCT诊断根管治疗后完全型牙根纵裂和不完全型牙根纵裂的差异无统计学意义（P〉O．05）。结论CBCT比根尖片诊断根管治疗后牙根纵裂的敏感度高,临床上可用CBCT辅助诊断早期牙根纵裂。     

CBCT在诊治埋伏阻生牙中的应用

目的:探讨CBCT在埋伏阻生牙诊治中的应用。方法:对56例(37颗多生牙、41颗阻生牙)经全景片检查需进一步明确诊断的埋伏阻生牙,进行CBCT扫描,通过三维重建、矢状位、冠状位及轴位断层进行分析。结果:与全景片比较,CBCT能准确定位埋伏阻生牙的位置、生长方向、数量,准确率差异有统计学意义(P<0.05)。结论:CBCT可以更直观、准确地对埋伏阻生牙定位,特别是在上颌前牙区的临床诊治更有应用价值。     

Detection of vertical root fractures by using cone beam computed tomography with variable voxel sizes in an in vitro model

Introduction

The aim of this study was to compare the diagnostic accuracy of cone beam computed tomography (CBCT) scans with different voxel resolutions in the detection of simulated vertical root fracture (VRF).

Methods

Sixty teeth, 30 with root fractures and 30 without, were examined through i-CAT tomography at 4 different voxel resolutions (0.125, 0.2, 0.3, 0.4 mm). Three observers scored the presence of VRF in all modalities. Sensitivity, specificity, likelihood ratio, and accuracy were calculated for each modality.

Results

Chi-square statistical analysis showed no significant difference among the resolutions or observers. However, positive likelihood ratio values of 24.5 for a 0.125-mm voxel, 24.25 for a 0.2-mm voxel, 13.2 for a 0.3-mm voxel, and 13 for a 0.4-mm voxel were found. Accuracy results confirmed the likelihood ratios as 0.97, 0.96, 0.93, and 0.92, respectively.

Conclusions

CBCT scans were reliable in detecting simulated VRF, and a 0.2-mm voxel was the best protocol, considering the lower x-ray exposure and good diagnostic performance.     

Detection of Vertical Root Fractures in the Presence of Intracanal Metallic Post: A Comparison between Periapical Radiography and Cone-beam Computed Tomography

Introduction

This in vitro study compared cone-beam computed tomography (CBCT) exam with different voxel sizes with digital periapical radiography in the detection of vertical root fractures in teeth with and without intracanal metallic posts.

Methods

Eighteen single-rooted human teeth were endodontically treated, prepared for cast metal posts, and artificially fractured. After positioning the teeth in dry mandibular sockets, the samples were subjected twice (with and without posts) to digital periapical radiography at 3 different angles and to CBCT examinations with 2 voxel sizes, 0.125 and 0.25 mm. The images were evaluated by 3 oral radiologists. Indices of sensitivity, specificity, and positive and negative predictive values, in addition to the areas under the receiver operating characteristic curves (accuracy), were calculated. Comparison of the accuracy of the imaging methods was assessed by using the χ² test. Comparison of the accuracy between teeth with and without posts was determined by using the Fisher exact test.

Results

The accuracy of the imaging methods showed no significant differences (P = .08). The comparison between teeth with and without posts in each examination revealed significant differences for CBCT with a voxel of 0.125 mm (P = .04) and for periapical radiography (P = .04).

Conclusions

No significant differences were observed between CBCT and periapical radiography in the detection of vertical root fractures, except for teeth with metallic posts in images from CBCT with a voxel of 0.125 mm and in digital periapical radiography. Furthermore, voxel size did not significantly influence the diagnosis of vertical root fractures.     

Detection accuracy of root fractures in cone‐beam computed tomography images: a systematic review and meta‐analysis

The aim of this review was to evaluate whether CBCT is reliable for the detection of root fractures in teeth without root fillings, and whether the voxel size has an impact on diagnostic accuracy. The studies published in PubMed, Web of Science, ScienceDirect, Cochrane Library, Embase, Scopus, CNKI and Wanfang up to May 2014 were the data source. Studies on nonroot filled teeth with the i‐CAT (n = 8) and 3D Accuitomo CBCT (n = 5) units were eventually selected. In the studies on i‐CAT, the pooled sensitivity was 0.83 and the pooled specificity was 0.91; in the 3D Accuitomo studies, the pooled sensitivity was 0.95 and pooled specificity was 0.96. The i‐CAT group comprised 5 voxel size subgroups and the 3D Accuitomo group contained 2 subgroups. For the i‐CAT group, there was a significant difference amongst the five subgroups (0.125, 0.2, 0.25, 0.3 and 0.4 mm; P = 0.000). Pairwise comparison revealed that 0.125 mm voxel subgroup was significantly different from those of 0.2, 0.25 and 0.3 mm voxel subgroups, but not from the 0.4 mm voxel subgroup. There were no significant differences amongst any other two subgroups (by α′ = 0.005). No significant difference was found between 0.08 mm and 0.125 mm voxel subgroups (P = 0.320) for the 3D Accuitomo group. The present review confirms the detection accuracy of root fractures in CBCT images, but does not support the concept that voxel size may play a role in improving the detection accuracy of root fractures in nonroot filled teeth.