两种影像测量技术在全口义齿牙槽骨高度测量中的应用研究

目的：研究线性体层摄影和曲面断层摄影两种测量技术在牙列缺失后牙槽骨高度测量中的应用价值。方法：选择牙槽骨条件较好的牙列缺失患者,采用OPl00-OT全颌曲面断层摄影机进行线性体层和曲面断层定点测量牙槽骨高度,通过KODAKDentalImagingSoftware软件的测量功能和定位钢珠进行放大校正后,分别测得牙槽骨高度。采用配对t检验和Pearson相关一致性检验,分析测量值的差异有无统计学意义,并进行两种测量结果的相关性分析。结果：在两种影像测量方法测得的牙槽骨高度差异没有统计学意义（P〉0．05）。线性体层摄影能够直观地观测牙槽骨的横断面结构,能够测量牙槽骨的宽度值变化。两种测量方法具有高度相关性（r=0．954,P〈O．01）。结论：应用线性体层摄影和曲面断层摄影技术进行牙槽骨高度测量结果具有一致性,线性体层可以观测牙槽骨的横断面结构,可以进行定点测量牙槽骨的三维结构。     

CBCT在上颌前牙即刻种植中的临床应用

目的：评价锥形束CT（CBCT）在上前牙区即刻种植临床中应用效果。方法：25例上颌前牙即刻种植患者为研究对象,进行CBCT扫描,在配套软件下分析拟种植区牙槽骨骨量及定位植入的情况,与临床手术实际效果进行对比研究。结果：25例上颌前牙即刻种植病例唇侧骨板平均厚度,CBCT测量为（1．4±0．32）mm,手术过程中实际测量为（1．4±0．2）mm,差异无统计学意义（P＞0．05）。结论：术前运用CBCT测量对上颌前牙牙槽骨的评估具有一定的临床指导作用。     

螺旋CT和曲面断层在种植术中的比较

目的:在牙种植过程中,比较螺旋CT和曲面断层的应用价值.方法:10例接受ITI种植的患者,在术前均接受螺旋CT和曲面断层的影像学检查.螺旋CT颌骨平扫并三维重建,曲面断层拍摄时放定位钢球.两种方法均定量测量术区颌骨高度及宽度.结果:螺旋CT图像比曲面断层清晰直观,测量精确.讨论与结论:曲面断层片可以显示颌骨全景,但是影像容易失真,不同位置放大率不同,无法精确评价颌骨细微结构.螺旋CT图像更清晰直观,测量精确,但是辐射剂量较大、费用较高.在种植领域,螺旋CT有更好的应用前景.     

离体牙长度的锥形束CT测量研究

目的:研究牙齿锥形束CT影像的垂直向放大误差及减小该误差的方法.方法:使用Galileo锥形束CT对32颗离体牙进行扫描,通过Galaxis3D软件对CBCT扫描数据进行重建,得到离体牙牙尖、根尖与扫描视野(FOV)中心所在的断层影像,并在该断层影像内测得离体牙的影像长度以及FOV中心至牙尖与根尖连线中点的距离(R值).将R值代入锥形束CT影像放大率校正方程,获得离体牙的校正长度;使用游标卡尺测得离体牙的实际长度;使用SPSS 16.0软件对数据进行统计学分析.结果:离体牙的CBCT影像长度大于实际长度且差异显著(P＜0.05),两者差值d1的均数为0.15±0.067mm,95％置信区间为0.13-0.21mm,平均误差百分比为0.74％±0.33％;离体牙的校正长度与实际长度之间差异不显著(P＞0.05),差值d2的均数为0.02±0.074mm,95％置信区间为-0.01-0.05mm,平均误差百分比为0.10％±0.36％;放大率M1与M2之间的差异不显著(P＞0.05).结论:牙齿在锥形束CT的影像长度大于实际长度,平均放大率为7.4‰,应用CBCT影像放大率校正方程可使牙齿影像长度平均放大率降低到1.0‰.     

颌骨骨量不足的牙种植术研究新进展

牙种植成功的一个首要条件就是要保证植入区有足够的牙槽骨。种植修复通常要求受植区的骨量高度不低于10mm,厚度不少于5mm。然而由于天然牙拔除后,剩余牙槽峭的宽度在1年内将减少约25％,且此过程持续进行,最终可导致50％的牙槽骨丧失。因此,临床上40％-60％的病例均存在骨量不足的问题,使种植体的植入与上部结构的修复均非常困难。目前针对颌骨骨量不足主要采用以下几种新技术：1）短种植体;2）颌骨植骨种植;3）引导骨组织再生术;4）上颌窦提升术;5）牙槽骨牵引成骨术;6）颧骨种植术。     

成人不同错牙合畸形分类与垂直型牙槽骨吸收的关系研究

目的：探讨成人错牙合畸形的分类与牙槽骨垂直吸收间的关系。方法：选择来我院行正畸治疗的18岁以上患者450例,对治疗前的石膏模型及全颌曲面断层片的辅助检查进行统计,按不同错牙合畸形分类标准进行诊断分类,并对牙槽骨垂直吸收进行统计分析。结果：按安氏错牙合畸形和矢状骨面型分类后,牙槽骨垂直吸收的患病率无显著差异（P＞0．05）;按垂直骨面型（FH－MP平面）分类后,均角、低角和高角的垂直型牙槽骨吸收患病率分别为22．2％、41．2％和32．9％（P＜0．05）,在两两比较中,低角和高角的垂直型牙槽骨吸收患病率均明显高于均角成年错牙合患者（P＜0．05）,而低角与高角组间无统计学差异（P＞0．05）。结论：在成年错牙合患者中,异常的垂直骨面型与牙槽骨的垂直吸收有一定相关性,提示临床治疗中对具有垂直向不调的成年错牙合畸形患者,更应关注其牙周健康及定期进行牙周维护性治疗。     

联合应用骨劈开、骨挤压术、引导骨组织再生技术并同期种植手术方案的短期临床疗效分析

目的    评价牙槽嵴唇（颊）鄂（舌）向宽度不足的患者联合应用骨劈开、骨挤压术及引导骨组织再生（GBR）技术并同期种植的短期临床疗效。方法    选取2009—2014年就诊于中国医科大学附属口腔医院种植中心的患者24例,联合应用骨劈开、骨挤压术,植入54枚种植体后同期植入骨粉,行GBR技术,术后4～6个月内完成上部结构修复。将54枚种植体按不同植入部位分为上颌前牙区、上颌后牙区、下颌前牙区及下颌后牙区4组,通过临床检查、X线片及锥形束CT（CBCT）等观察比较4组种植体手术前后及术后半年牙槽骨宽度的变化,修复后6个月及1年的骨高度变化等。结果    种植手术当天至修复后1年的临床随访检查显示,无种植体松动,全部种植体行使功能良好,存留率100%。种植术后牙槽骨宽度与术前相比,差异有统计学意义（P＜0.05）。牙槽骨宽度在术后与术后半年的对比中,差异无统计学意义（P＞0.05）。术后半年,比较4组植入部位的骨宽度变化,差异无统计学意义（P＞0.05）。修复后6个月及1年,比较4组植入部位的骨高度变化,差异均无统计学意义（P＞0.05）。结论    对牙槽嵴唇（颊）鄂（舌）向宽度不足的患者,联合应用骨劈开、骨挤压术和GBR技术并同期种植,可增加骨量,达到牙槽嵴宽度的水平扩增。不同种植部位对种植体周围骨组织吸收量没有明显影响。     

几种骨量测定方法在上颌骨中应用的比较研究

目的:探讨不同骨量测定方法在上颌骨骨量测定中的应用价值,为上颌骨牙种植手术方案的制定提供依据。方法:采用手工直接测量(DM)法、螺旋CT测量法、X线曲面体层(OP)测量法对15副头颅标本的牙槽骨高度、宽度进行测量,比较研究螺旋CT与OP骨高度值及骨宽度值的失真率;并在螺旋CT三维重建图像上对上颌窦底壁、上颌唇(颊)侧骨板的骨质形貌进行观察分析。结果:螺旋CT扫描三维重建在显示上颌骨骨质内部结构和表面形貌,测量缺牙区骨量以及与邻牙、上颌窦等的距离等方面优于DM法和OP法。结论:螺旋CT对上颌骨牙种植术的骨量测定有重要的价值。     

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。     

X线图象的数字化处理与计算机测量：100枚牙种植体周围结构 …

采用ＡＲＩＥＳ－Ⅱ图象分析系统，对１００枚已植入颌骨内的牙种植体Ｘ线片数字图象中的种植体周围间隙宽度值，间隙灰度值，牙槽骨高度值进行了计算机测量。结果表明牙种植体受载后在颌骨内经历了骨的吸收与重建，其骨高度的改变于一年后趋于稳定进入正常生理改变，间隙宽度变化与时间成象机相关。间隙灰度的测量结果无统计学意义。     

Accuracy in measurement of distance using limited cone-beam computerized tomography

PURPOSE: The purpose of this study was to evaluate the accuracy of measurement of distance on the images produced by limited cone-beam computerized tomography (CT). MATERIALS AND METHODS: Five cadaver mandibles were examined by spiral computerized tomography (SCT) and limited cone-beam computerized tomography (LCBCT). The vertical distance from a reference point to the alveolar ridge was measured by caliper on the sliced mandible, and measurement error on the CT images was calculated in percentages based on the actual values and the measurement values obtained from the CT images. RESULTS: Measurement error was determined to range from 0 to 1.11 mm (0% to 6.9%) on SCT and from 0.01 to 0.65 mm (0.1% to 5.2%) on LCBCT, with measurement errors of 2.2% and 1.4%, respectively (P < .0001). DISCUSSION: This study suggests that distance can be measured accurately using LCBCT. The size of the rectangular solid images obtained using LCBCT (30 mm wide and 42.7 mm long) is thought to be adequate for observation of mandibular bony structure and for preoperative assessment before dental implant placement. CONCLUSION: In this experiment on cadaver mandibles, LCBCT was shown to be a useful tool for preoperative evaluation in dental surgery because the relatively small field size of its images limits the patient's exposure to radiation.     

Correlation and accuracy of contrast-enhanced computed tomography in assessing depth of invasion of oral tongue carcinoma

The aim of this study was to evaluate the correlation and accuracy of depth of invasion (DOI) measurement from preoperative contrast-enhanced computed tomography (CECT) scans in comparison to histopathological examination (HPE) in oral tongue squamous cell carcinoma (OTSCC). Preoperative CT scans of 18 OTSCC patients were reviewed retrospectively by a single observer to measure the DOI on axial and coronal sections; these were then compared to the HPE report. Mean DOI was compared between CECT and HPE using repeated measures ANOVA. The strength of correlation of CT-derived tumour depth was determined using the intra-class correlation coefficient (ICC) followed by assessment of accuracy by Bland–Altman plot. In general, the measurement of DOI was smaller on CECT, with a mean difference of 0.743 mm on axial CT and 1.106 mm on coronal CT. Regarding the correlation between CECT and HPE tumour depths, ICC was 0.956 for axial CT and 0.965 for coronal CT. Bland–Altman analysis showed that DOI from CECT and histopathological depth were in agreement with each other. In conclusion, there was excellent correlation and accurate measurement of DOI from CECT.     

基于光谱CT的钙抑制技术评估颞下颌关节紊乱病患者关节盘位置

目的探索钙抑制光谱CT技术在评估颞下颌关节盘位置及测量关节盘后带厚度中的应用。方法对2019年2至7月解放军总医院海南医院放射科门诊就诊的23例颞下颌关节紊乱病患者[平均年龄23岁(12~62岁),男性14例,女性9例]行MRI斜矢状位、斜冠状位质子密度加权成像及光谱CT扫描,共纳入可评估关节45侧,依扫描设备分为MRI测量组及钙抑制光谱CT测量组。采用钙抑制算法对光谱CT进行去钙处理,并重建斜矢状位及冠状位钙抑制光谱CT图像。基于斜矢状位及冠状位图像评估关节盘位置,基于斜矢状位图像测量关节盘后带最大厚度。结果45侧颞下颌关节盘位置在MRI图像及钙抑制光谱CT图像上基本一致。MRI测量组与钙抑制光谱CT测量组所测后带厚度的组内相关系数为0.843(0.712,0.914),Bland-Altman图分析MRI与钙抑制光谱CT测量关节盘后带厚度的差值点[95.6%(43/45)]位于95%一致性界限内。Wilcoxon配对检验提示MRI测量组[2.57(1.76,3.65)mm]与钙抑制光谱CT测量组[2.67(1.74,4.56)mm]差异无统计学意义(P=0.07)。结论钙抑制光谱CT成像可以准确评估关节盘位置及关节盘后带厚度。     

Soft and Hard Tissue Remodeling after Endodontic Microsurgery: A Cohort Study

IntroductionThe aim of this study was to investigate the impact of the incision type, with or without a coronally repositioning flap (CRF), on soft tissue healing and crestal bone remodeling after endodontic microsurgery (EMS).MethodsClinical pictures and cone-beam computed tomography images from 47 patients (120 teeth) taken before surgery and at the follow-up appointment were included in this study. Clinical pictures were qualitatively evaluated by 2 endodontists for the gingival marginal level (GML) (recession, same position, or coronal root coverage), papillary height (same position/receded), and for presence/absence of scars for each tooth. Cone-beam computed tomography images were used to calculate the changes in the distance between the cementoenamel junction and the crestal bone level (CBL) between the preoperative and follow-up scans. Statistical analyses were performed to determine a correlation between patient-related factors (age, sex, tooth type, position, and presence/absence of a crown), incision techniques, and changes within the CBL.ResultsGingival recession was more prevalent in mandibular teeth, molar teeth, and teeth that received intrasulcular or papilla-based incisions (P < .05). Scar formation was affected by the flap design (P < .05). CRF was the only technique resulting in coronal root coverage (P < .05). There were no changes observed in the papillary height between the various flap designs. There was also no statistically significant difference in the crestal bone height between the preoperative and follow-up scan measurements (P > .05).ConclusionsSoft tissue changes are evident after EMS and can be affected by the flap design selected, as well as the site being treated. Application of CRF can improve the position of GML after EMS. There are insignificant changes within the CBL at the facial aspect of the root after EMS.     

颌面专用CT下颌骨检查技术

目的：研究颌面专用CT（QR-DVT 9000 NEWTOM）下颌骨检查技术的建立方法及技术要点,观察颌面专用CT下颌骨检查技术,在下颌骨X线检查中的优势.方法：对下颌骨疾病患者进行颌面专用CT扫描和重建成像,对其重建轴位影像进行曲面、矢状位、冠状位以及3D影像的后处理,并与常规X线片对比分析.结果：颌面专用CT下颌骨检查技术优于下颌骨常规X线检查,分别以水平位、曲面、矢状位、冠状位以及3D等多方位影像显示下颌骨的信息.结论：颌面专用CT下颌骨检查技术,在下颌骨的X线检查中有着明显的优势,并能够有效地指导临床手术.     

COMPUTED TOMOGRAPHY IMAGING STRATEGIES AND PERSPECTIVES IN ORBITAL FRACTURES

Objective:

The objective of this study was to demonstrate the sensitivity and specificity of multislice computed tomography (CT) for diagnosis of orbital fractures following different protocols, using an independent workstation.

Materials and methods:

CT images of 36 patients with maxillofacial fractures (symptomatic to orbit region) who were submitted to multislice CT scanning were analyzed, retrospectively. The images were interpreted based on 5 protocols, using an independent workstation: 1) axial (original images); 2) multiplanar reconstruction (MPR); 3) 3D images; 4) association of axial/MPR/3D images and 5) coronal images. The evaluated anatomical sites were divided according to the orbital walls: lateral (with or without zygomatic frontal process fracture); medial; superior (roof) and inferior (anterior, medial). The collected data were analyzed statistically using a validity test (Youden''s J index; p<0.05). The clinical and/or surgical findings (medical records) were considered as the gold standard to corroborate the diagnosis of the anatomical localization of the orbital fracture.

Results:

3D-CT scanning presented sensitivity of 78.9%, which was not superior to that of MPR (84.0%), axial/MPR/3D (90.5%) and coronal images (86.1%). On the other hand, the diagnostic value of axial images was considered limited for orbital fractures region, with sensitivity of 44.2%.

Conclusions:

Except for the axial images, which presented a low sensitivity, all methods evaluated in this study showed high specificity and sensitivity for the diagnosis of orbital fractures according to the proposed methodology. This protocol can add valuable information to the diagnosis of fractures using the association of axial/MPR/3D with multislice CT.     

Association between preoperative inferior rectus muscle swelling and outcomes in orbital blowout fracture

Purpose

In 18 patients with orbital blowout fracture who underwent reconstruction using a bone autograft, the association between preoperative inferior rectus muscle swelling and the outcome 1 year after the operation was evaluated.

Material and methods

The patients were classified according to outcomes into four groups: Group A without double vision showing normal ocular movements, Group B with double vision showing normal ocular movements, Group C with double vision showing improvement in ocular movements, and Group D with double vision showing no improvement in ocular movements. Inferior rectus muscle swelling was evaluated by calculating its swelling rate on the injured compared with the non-injured side on preoperative coronal CT images.

Results

Concerning outcomes, 12, 2, and 4 patients were classified as Groups A, B, and C, respectively, and no patient was classified as Group D. The inferior rectus muscle swelling rate was ≤1.2 in Group A, and 1.6–2.4 in Groups B and C.

Conclusion

In patients in whom inferior rectus muscle swelling on the injured is ≥1.6 times that on the non-injured side on preoperative coronal CT images, double vision and slight impairment of eye movements may remain after surgery.     

Relationship among Schneiderian Membrane,Underwood's Septa,and the Maxillary Sinus Inferior Border

Background: Osseo‐integrated implants are increasingly being used to restore functional dentition; however, in the posterior region, implant placement can be problematic because of inadequate bone height. In this condition, maxillary sinus floor elevation surgery has become the treatment of choice. The presence of anatomic variations within the maxillary sinus such as Underwood's septa and thin schneiderian membrane decreases the success of the sinus floor elevation. Purpose: In this study, we tried to determine the relationship between the anatomic variations of the maxillary sinus: Underwood's septa, schneiderian membrane thickness, and the cortical thickness of the inferior border of the maxillary sinus. Material and Methods: The left and right maxillary sinus images of 74 patients were obtained by using dental computed tomography (CT). The schneiderian membrane and the cortical thickness of the inferior border of the maxillary sinus were measured on the coronal images of dental CT scans at the deepest portion of the sinus cavity. The presence of Underwood's septa was identified on the axial images. The correlations between these variables were assessed. Results: We found that there was only a negative correlation between the schneiderian membrane thickness and the presence of Underwood's septa (r = –0.168 p = .042). Conclusion: It is suggested that Underwood's septa may be the reason for the thinness of the schneiderian membrane. However, future studies among larger groups are necessary for confirming the finding by using well‐designed clinical studies.     

EVALUATION OF SIMULATED BONE LESION IN THE HEAD OF THE MANDIBLE BY USING MULTISLICE COMPUTED TOMOGRAPHY

Conventional radiography has shown limitation in acquiring image of the ATM region, thus, computed tomography (CT) scanning has been the best option to the present date for diagnosis, surgical planning and treatment of bone lesions, owing to its specific properties. Objective: The aim of the study was to evaluate images of simulated bone lesions at the head of the mandible by multislice CT. Material and methods: Spherical lesions were made with dental spherical drills (sizes 1, 3, and 6) and were evaluated by using multislice CT (64 rows), by two observers in two different occasions, deploying two protocols: axial, coronal, and sagittal images, and parasagittal images for pole visualization (anterior, lateral, posterior, medial and superior). Acquired images were then compared with those lesions in the dry mandible (gold standard) to evaluate the specificity and sensibility of both protocols. Statistical methods included: Kappa statistics, validity test and chi-square test. Results demonstrated the advantage of associating axial, coronal, and sagittal slices with parasagittal slices for lesion detection at the head of the mandible. Results: There was no statistically significant difference between the types of protocols regarding a particular localization of lesions at the poles. Conclusions: Protocols for the assessment of the head of the mandible were established to improve the visualization of alterations of each of the poles of the mandible''s head. The anterior and posterior poles were better visualized in lateral-medial planes while lateral, medial and superior poles were better visualized in the anterior-posterior plane.     

锥形束CT影像非目标检查区的诊断意义

目的:讨论对颌面部行锥形束CT有目的检查的同时,注意观察非目的检查区异常影像的临床意义。方法:使用QR DVT 9000 New Tom锥形束CT(简称锥形束CT),在口颌面部成像的基础上,在轴位、冠状、矢状、任意位重建影像上,建立座标点,并进行定位定性测量。结果:发现在2764例受检患者中,分别有种植牙、颞下颌关节、茎突测量、埋伏牙定位、牙体牙髓病变、颌骨肿瘤、共分六种有目的检查组成。其中非目的检查区发现影像异常者四例,分别为舌体静脉瘤结石、舌下腺导管结石、左下颌升支前内侧金属异物及面后静脉区血管瘤结石影像。结论:使用锥形束CT对颌面部进行有目的检查诊断的同时,应提高全面评价其他组织内异常影像的意识,警惕遗漏非目标检查区异常影像信息的观察,并评估其性质,指导临床诊断治疗。