上颌阻生尖牙患者寰椎形态变异情况的锥形束CT研究

目的 利用锥形束CT(cone-beam computed tomography,CBCT)研究上颌尖牙唇(腭)侧阻生(BIC/PIC)的患者寰椎形态变异的发生情况,以期辅助上颌阻生尖牙的预测和早期干预。方法 选取196例上颌阻生尖牙患者(研究组)和196例年龄、性别、安氏分类与之相匹配的尖牙正常萌出者(对照组)。将所有样本的CBCT导入Dolphin软件,重建头颅侧位片和三维图像,观察并记录各组寰椎后桥及寰椎后弓发育缺陷(包括寰椎后弓发育不全和寰椎后椎弓裂隙)的发生情况,并使用SPSS软件进行统计分析。结果 研究组寰椎后桥的发生率为32.6%,显著高于对照组(22.4%,P=0.024)。PIC组寰椎后桥发生率显著高于对照组(P=0.005),BIC组和对照组、BIC和PIC组之间无统计学差异(P>0.05)。寰椎后弓发育缺陷研究组和对照组之间的发生率并无统计学差异(P>0.05)。结论 上颌尖牙阻生患者较尖牙正常萌出者更容易发生寰椎后桥。     

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。     

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。     

上颌埋伏尖牙定位及邻牙牙根吸收的多层螺旋CT分析

目的:应用多层螺旋CT(MSCT)对上颌埋伏尖牙进行三维立体定位,同时对邻牙牙根的吸收程度进行评估。方法:应用MSCT扫描38例上颌埋伏尖牙,在多平面重建和容积再现软件中对其三维定位,上颌切牙牙根吸收程度进行分析,并与传统X线平片进行比较。结果:38例上颌埋伏尖牙都能使用MSCT进行准确定位,侧切牙牙根吸收率为36.6%,中切牙的牙根吸收率为16.3%,在牙列中受埋伏尖牙影响最大的是侧切牙的牙根。MSCT评价上颌中切牙及侧切牙牙根吸收的阳性率高于传统X线平片,其差异具有统计学意义。结论:使用MSCT多平面重建和容积再现技术能直观准确地对埋伏尖牙进行定位、诊断邻牙牙根吸收程度,对临床正畸治疗埋伏牙有很高的应用价值。     

曲面断层片诊断阻生上颌尖牙造成的切牙牙根吸收的有效性研究

目的：评价全口曲面断层片对上颌阻生尖牙造成的切牙牙根吸收诊断的有效性。方法：选取上颌尖牙阻生病例19例,拍摄全口曲面断层片及螺旋CT扫描,邀请10名口腔正畸学研究生通过曲面断层片判断阻生尖牙造成的切牙牙根吸收的数目和位置,以螺旋CT扫描结果为实际牙根吸收量,计算曲面断层片诊断的灵敏度和特异度。结果：曲面断层片对上颌尖牙阻生造成的切牙牙根吸收诊断的灵敏度为46.3%、特异度为86.5%。阴性诊断有一定的参考价值,阳性诊断因为缺少可靠的牙根吸收定性指标而准确性较低。结论：不能单独依靠曲面断层片做出是否存在切牙牙根吸收的诊断。     

上颌尖牙阻生的诊断和早期干预

上颌尖牙阻生是正畸医生经常碰到的问题之一,其处理方法通常包括外科开窗和较复杂的正畸治疗.上颌尖牙阻生可以通过观测X线片中尖牙近远中向位置的异常进行早期预测,早期的临床干预手段则包括拔除乳尖牙、拔除乳尖牙联合应用口外弓颈牵引、快速上颌扩弓,本文就这2方面内容作一综述.     

口腔种植术前锥形束CT影像评估上颌窦状况

锥形束CT（CBCT）在种植术中具有非常重要的作用,通过CBCT可以了解种植术前术后的情况,判断种植体植入前植入床的基本条件,判断能否进行种植、种植植入方向、方法以及术后评估等。涉及到上颌窦的种植术应常规拍摄CBCT。本文通过临床实例介绍使用CBCT进行种植术前上颌窦分析评估及判断术后可能发生的改变。     

上颌后牙区无牙位点在锥形束CT中的解剖学表现

目的 基于锥形束CT（CBCT）分析上颌后牙区无牙位点的相关骨解剖特点。方法 本项研究共选取了上颌后牙区至少有一个缺牙的100名患者的CBCT图像资料,共217个无牙位点。测量无牙位点的剩余牙槽嵴高度、剩余牙槽嵴宽度和角度A,并分析上颌窦底的形态特点。结果 平均剩余牙槽嵴高度为9.53 mm,其中小于10 mm者占62.67%（136/217）。平均剩余牙槽嵴宽度为9.30 mm,大于6 mm占91.71%（199/217）。磨牙区剩余牙槽嵴高度小于前磨牙区,剩余牙槽嵴宽度呈相反趋势。上颌窦底形态以倾斜型（64.52%）为主。角度A小于30°、30°~60°和大于60°者分别占10.14%、42.40%和47.47%。结论 上颌后牙区缺牙位点进行种植手术前,多数需行上颌窦底提升手术增加骨量,建议根据CBCT检查结果评价上颌窦解剖结构从而制定合理的种植方案。     

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目的利用锥形柬计算机断层扫描（CBCT）研究上颌第一磨牙近中颊根第二根管（MB2）发生率、根管解剖形态以及根管口位置分布。方法随机选取2011-2013年航天中心医院口腔科20～30岁患者CBCT影像160张（男80张、女80张）。平行近中颊根长轴平面观察其根管形态,并按照Vertucci分类统计。水平面观察根管口的位置,记录MB、MB2及腭根根管口间距离以及MB、MB2根管口分别到腭根根管口连线夹角,并比较不同性别间差异。结果本研究观察了279颗上颌第一磨牙,其中存在MB2牙齿233颗,检出率为83．5％,不同性别间差异无统计学意义（P〉0．05）。不同类型的根管出现概率不同,各类型出现率男女间无差异。MB与MB2根管口间距男性为（2．195±0．504）mm,女性为（1．966±0．419）mm,差异有统计学意义（P〈0．05）。结论上颌第一磨牙MB2发生率高,不同类型MB2发生概率不同,男性与女性之间无差异。MB与MB2根管口间距在两性之间存在统计学差异。     

Risk factors for external root resorption of maxillary second molars due to impacted third molars as evaluated using cone beam computed tomography

The purpose of this retrospective study was to evaluate risk factors for external root resorption (ERR) on maxillary second molars (MxM2) in association with impacted third molars (MxM3) using cone beam computed tomography (CBCT) scans. The angles between the axes of MxM2/MxM3 (inclination) were measured. Further, ERR on MxM2 was classified as absent, slight, moderate, or severe. Contact location between MxM3 and MxM2, the size of the dental follicle, type of impaction, root formation, and patient demographic characteristics were also assessed. Half of the 84 MxM2 showed ERR (slight 36.9%, moderate 6.0%, severe 7.1%). Patient age was a significant factor for the presence of ERR (P = 0.03). The inclination was also a relevant factor, with transverse MxM3 exhibiting the highest risk of ERR (P = 0.02). The cervical third (28.6%) showed a significantly lower risk percentage of ERR compared to the apical (73.7%) and middle thirds (60.6%) of the root (P = 0.004). Based on these findings, clinicians assessing the need for surgical removal should be able to selectively identify impacted MxM3 at risk of causing ERR on MxM2 early on, especially when the MxM3 is located in close contact with the apical and middle thirds of the MxM2 roots and has a transverse inclination.     

Anatomical characteristics of maxillary sinus septa visualized by cone beam computed tomography

Proper implant positioning in the posterior region of the edentulous maxilla commonly requires sinus floor elevation. Maxillary sinus septa increase the risk of membrane perforation during sinus floor elevation. The purpose of this retrospective, cone beam computed tomography (CBCT)-based study was to examine the frequency, number, location, and orientation of antral septa in the maxillary sinus. Further, possible associated factors were assessed. Measurements were performed on CBCT scans of 301 patients (602 sinuses). The data were analysed statistically with respect to patient age, sex, and dentition type. One or more septa were detected in 117 patients (38.9%). A total of 188 septa were found in the 602 sinuses (31.2%). Septa were most often coronally oriented (53.2%), followed by sagittal (24.5%) and transverse (22.3%) orientations. Septa were most often found in the region of the first and second molar (37.2%), followed by the posterior region of the third molar (33.0%) and the anterior region of the premolars and canines (29.8%). A significant association was found between edentulism and the presence of septa. For edentulous patients, the septa were most often transversally oriented. Maxillary sinus septa are encountered in every third patient. This may have an influence on the performance of sinus floor elevation.     

Perforation of the maxillary sinus floor during apical surgery of maxillary molars: A retrospective analysis using cone beam computed tomography

This retrospective analysis assessed a possible correlation of perforation of the maxillary sinus floor during apical surgery of maxillary molars and the distances from the treated apices/periapical radiolucencies to the sinus floor. The material included 168 apical surgeries of maxillary first or second molars performed from 1999 to 2016. In 22 (out of 33) perforation cases, a preoperative cone beam computed tomography (CBCT) was available. These cases were defined as the test group. From the pool of operated cases without sinus floor perforation, matching cases – that is, same treated tooth, similar age and same gender – were selected as a control group (N = 26). Mean linear distances from root apices or radiolucencies to sinus floor were significantly shorter in the test group compared to the control group. In conclusion, perforation cases were significantly closer to the sinus floor than cases without perforation.     

Root and canal morphology of the maxillary second premolars as indicated by cone beam computed tomography

The aim was to evaluate the morphology of maxillary second premolars. The root canal configurations were classified according to Vertucci and a new system by Ahmed et al. based on CBCT images. In addition, the number of roots and the level where they bifurcated were identified, and morphological measurements were performed based on anatomical landmarks. Single-rooted forms were most common. Bifurcation occurred most often in the middle part of the root. The most common canal configuration was type I according to Vertucci and code ¹SP¹ according to the new classification. The measurements showing the results were as follows (mm): palatal cusp/buccal cusp/the lowest point of the occlusal surface to pulp chamber ceiling 6.18/6.54/4.77; the ceiling of the pulp chamber was found at the CEJ in 92.28% of the specimens. The maxillary second premolars tended to be single-rooted and with one root canal.     

上颌阻生尖牙牵引治疗后邻近切牙牙根吸收情况的研究

目的 分析上颌阻生尖牙正畸牵引治疗后邻近切牙的牙根吸收情况及可能的相关因素。方法 选取上颌尖牙阻生且符合标准的43例患者,年龄10～23岁,共60颗上颌埋伏阻生尖牙。上颌阻生尖牙正畸牵引治疗前后分别拍摄锥形束CT,分析阻生尖牙邻近切牙的牙根吸收程度,并对可能存在的相关因素进行分析。结果 上颌阻生尖牙正畸牵引治疗后,上颌中切牙发生轻、中、重度牙根吸收的概率分别为71.7%、15.0%、13.3%,上颌侧切牙发生轻、中、重度牙根吸收的概率分别为48.3%、36.7%、15.0%,上颌中切牙与侧切牙牙根吸收严重程度存在差异(P<0.05)。位于腭侧及颌骨内、低位且靠近面中线的阻生尖牙,在正畸牵引治疗后,侧切牙牙根吸收程度较重(P<0.05)。低位阻生尖牙牵引治疗后,中切牙牙根吸收较重(P<0.05)。牵引时间较长时,中切牙牙根吸收程度较重(P<0.05)。治疗前已发生牙根吸收的切牙,在阻生尖牙牵引治疗后发生的牙根吸收程度较重(P<0.05)。结论 上颌侧切牙在阻生尖牙正畸牵引治疗后,发生的牙根吸收程度较重。上颌阻生尖牙正畸牵引治疗后,邻近切牙牙根吸收情况与阻生尖...     

锥形束CT在诊治阻生牙所致邻牙牙根外吸收中的应用

目的 探讨锥形束CT（CBCT）在阻生牙所致邻牙牙根外吸收诊治中的应用价值。方法 选择2011年1-12月广州军区武汉总医院口腔科诊治,经全口曲面体层片确定存在阻生牙,邻牙牙根外吸收情况不明确的患牙19颗（15例）。所有患者进行CBCT扫描和三维重建,确定牙根外吸收的部位及程度。结果 经CBCT扫描和三维重建后,所有患者均直观显示牙根外吸收的部位及程度,以及阻生牙在颌骨中的三维位置及其与周围重要组织的关系。结论 CBCT可直观、准确地显示牙根外吸收的部位和程度,对阻生牙所致邻牙牙根外吸收的诊断和治疗提供可靠信息。