ProTaper和K3预备对上颌前磨牙根管形态影响的研究

目的比较ProTaper和K3预备对根管形态的影响。方法选取正畸减数拔除含颊舌双根管的上颌前磨牙40颗,随机分为2组,分别采用机用镍钛器械ProTaper和K3预备根管,预备前、后进行三维成像,记录预先设立的根管横断面、颊舌向切面、近远中向切面三个位点的三维数据,评价根管预备的效果。结果 K3组相对于ProTaper组对牙本质的切削量少,对根管形态的影响较小,ProTaper组和K3组有显著性差异(P<0.01);结论 K3组预备后的根管形态优于ProTaper组。K3预备后能较好的保持根管形态,对根管壁牙本质的切削量少,较少地削弱了余留牙体组织的抗折力。     

锥形束CT在阻生齿拔除术中的应用

目的:应用锥形束CT(CBCT)观测及分析阻生齿与邻近解剖结构的关系,为临床手术提供参考依据.方法:在第三磨牙拔除术前摄曲面断层X线片检查,对于与下牙槽神经管接触或部分重叠的病例35例,进行锥形束CT检查.结果:锥形束CT对阻生齿拔除术能更好的进行阻力分析.结论:锥形束CT检查对于第三磨牙拔除术手术方案的选定具有一定的指导意义.     

Comparison of scattered entrance skin dose burden in MSCT,CBCT, and X-ray for suspected scaphoid injury: Regional dose measurements in a phantom model

IntroductionScaphoid radiography has poor sensitivity for acute fracture detection and often requires repeat delayed imaging. Although magnetic resonance (MR) imaging is considered the gold standard, computed tomography (CT) is often used as an alternative due to ease of access. Cone-Beam CT (CBCT) offers equivalent diagnostic efficacy to Multi Slice CT (MSCT) at reduced dose. We aimed to establish the difference in scattered dose between modalities for scaphoid imaging.MethodsAnatomical regional entrance surface dose measurements were taken at 3 regions on an anthropomorphic torso phantom positioned as a patient to a wrist phantom undergoing scaphoid imaging for three modalities (CBCT, MSCT, four-view projection radiography). Exposure factors were based on audit of clinical exposures. Each dose measurement was repeated three times per anatomical region, modality, exposure setting and projection.ResultsUnder unpaired T-test CBCT gave significantly lower mean dose at the neck (1.64 vs 18 mGy), chest (2.78 vs 8.01) and abdomen (1.288 vs 2.93) than MSCT (p < .0001). However CBCT had significantly higher mean dose than four-view radiography at the neck, chest and abdomen (0.031, 0.035, and 0.021 mGy) (p < .0001).ConclusionCBCT of the wrist carries a significantly higher scattered radiation dose to the neck, chest and abdomen than four view scaphoid radiography, but significantly lower scattered dose than MSCT of the wrist of equivalent diagnostic value.Implications for practiceThe use of CBCT for scaphoid injury carries significantly lower scattered dose to radio-sensitive structures investigated here than equivalent MSCT, and may be of greater use as an early cross-sectional investigation for suspected scaphoid fracture.     

藏族和汉族上颌第一恒磨牙近中颊根的CBCT对比研究

目的:比较藏族和汉族上颌第一恒磨牙近中颊根数据,为临床提供参考。方法:随机收集藏族和汉族患者上颌第一恒磨牙近中颊根CBCT图像440例,测量根长、弯曲度、弯曲位置、是否有第二近颊根(MB2)、MB-MB2距离。结果:藏族第一恒磨牙近中颊根长度较汉族长,差异有统计学意义(P<0.05)。近中颊根根管弯曲度比较,藏汉族有统计学差异,汉族以2级(10°<根管弯曲度<30°)居多,而藏族不仅2级较多,3级(根管弯曲度>30°)也较汉族多。根管弯曲位置方面,汉族以根管中分的弯曲居多,而藏族不仅根管中分的弯曲较多,根管口和根尖弯曲也较多,差异有统计学意义(P<0.05)。藏汉族的MB2发生率、MB-MB2距离比较差异无统计学意义。结论:藏族和汉族上颌第一恒磨牙近中颊根的根长、根管弯曲度、根管弯曲位置有差别,藏族牙根更长,弯曲度更大,特别是根尖区弯曲度,值得临床注意。而MB2发生率和MB-MB2距离藏汉族无差异。     

基于锥形束CT对邻面接触区釉质厚度的测量与分析

目的    应用锥形束CT（cone beam computed tomography,CBCT）测量上下颌牙列邻面接触区釉质厚度及邻接点距离牙合面和釉牙骨质界的垂直高度,为临床邻面去釉提供参考数据。方法    选取2019年6—10月于吉林大学口腔医院医学影像科行CBCT检查患者50例,根据纳入标准选取符合测量条件的牙齿145颗,运用Invivo软件测量每颗牙齿邻面接触区的釉质厚度及邻接点距离牙合面和釉牙骨质界的垂直高度。结果    从切牙至第一磨牙邻面接触区釉质厚度有逐渐增大的趋势;大多数牙位的远中邻面接触区釉质厚度大于近中（P < 0.05）,仅有上颌第一前磨牙和下颌第一磨牙的近远中邻面接触区釉质厚度差异无统计学意义（P > 0.05）;上下颌左右侧同名牙邻面接触区釉质厚度差异无统计学意义（P > 0.05）;除上颌中切牙-侧切牙、上下颌侧切牙-尖牙邻面接触区外,其余相邻牙齿近远中邻面接触区釉质厚度相似,差异均无统计学意义（均P > 0.05）;上颌邻面接触区平均釉质厚度大于下颌,差异有统计学意义（P < 0.05）;上下颌近远中邻接点到牙合面的垂直距离均小于到釉牙骨质界的垂直距离（均P < 0.05）。结论    不同牙位近远中邻面接触区釉质厚度不同,邻接点距离牙合面和釉牙骨质界的垂直高度也不同,临床邻面去釉时不同牙位去釉量不能按照同一标准进行,应结合CBCT影像资料制定个体化治疗方案。     

Orthodontic management of a complete and an incomplete maxillary canine-first premolar transposition

Maxillary canine and first premolar transposition is a complicated dental anomaly to treat, especially if the clinician''s goal is to orthodontically move the canine into its normal position. Early diagnosis with cone-beam computed tomography simplifies the treatment of this pathology. This case report describes a patient with bilateral transposition, one complete and the other incomplete, involving the maxillary canine and the first premolar (Mx.C.1P). The orthodontic treatment involved the correction of both transpositions. In the complete transposition, the traction was mesial and upward to move the canine into a more apical position with a wider dentoalveolar process for easier crown interchange.     

Evaluation of condyle-fossa relationships in adolescents with various skeletal patterns using cone-beam computed tomography

Objectives:To evaluate the condyle-fossa relationship in adolescents with various skeletal patterns using cone-beam computed tomography (CBCT).Materials and Methods:CBCT images obtained in 120 adolescent patients were used for this study. The patients were divided into 3 groups according to 3 criteria: (1) age (early, middle, and late adolescence); (2) facial height ratio or Jarabak quotient (hyperdivergent, normodivergent, and hypodivergent); and (3) ANB classification (Class I, Class II, and Class III). Temporomandibular joint space (TMJS: AS, anterior space; SS, superior space; PS, posterior space; MS, medial space; LS, lateral space), width and depth of the condyle (MLT, mediolateral thickness; APT, anteroposterior thickness), articular slope (ArS) and vertical height of the fossa (VHF) were measured and compared using CBCT.Results:Differences in condyle-fossa relationships were not significantly different between male and female adolescents, but were significantly different (P < .05) between left and right sides. The mean values showed no statistical differences according to age and skeletal pattern. Most measurements in the sagittal view showed that SS was the greatest, and the mean ratio of AS to SS to PS was 1.00 to 1.27 to 1.19, respectively. The mean values of coronal MS and LS were not significantly different.Conclusions:There were almost no statistical differences in the TMJS in adolescents across various factors except between left and right sides.     

基于CBCT的下颌第一磨牙区即刻种植相关的影像学研究

目的利用CBCT研究下颌第一磨牙区即刻种植适宜的植入位点、植入角度与植入深度,为术前数字化设计和临床操作提供参考依据。方法选取100例符合纳入标准的患者CBCT影像学资料,测量下颌第一磨牙区的牙槽骨厚度、颊侧及舌侧骨板厚度、牙根间隔宽度,同时测量下颌第一磨牙与下颌神经管及舌侧骨倒凹的关系,并进行统计学分析。结果由近中至远中,下颌第一磨牙的牙槽骨厚度及颊侧骨板厚度逐渐增大,舌侧骨板厚度逐渐减小;由牙槽嵴顶至根尖,牙根间隔宽度逐渐增大,最大为(5.00±1.42)mm;近中根、远中根、远舌根、牙根间隔顶至下颌神经管的距离分别为(7.47±2.38)mm、(7.19±2.49)mm、(9.59±1.94)mm、(15.90±2.39)mm;由近中至远中,下颌神经管颊侧及舌侧骨板最大厚度分别为(6.54±1.25)mm、(2.53±0.84)mm;下颌舌侧骨倒凹角度为(149.67±8.30)°,倒凹深度为(1.51±0.43)mm。结论在下颌第一磨牙区即刻种植前可通过CBCT规划合适的种植路径,注意避开下颌神经管和舌侧骨倒凹。若根尖至下颌神经管的安全距离足够,可从牙根间隔处植入,若安全距离不足,植入位点可偏近中舌侧,植入角度可适当舌倾。     

CBCT对下颌第三磨牙手术术式选择的影响作用

目的:评估CBCT对下颌第三磨牙拔除术式选择的影响。方法:选择130例符合手术适应症的下颌第三磨牙,通过使用两种放射学检查方法作为术前检查:(1)全景片检查;(2)CBCT检查。在经放射学检查之后,手术方案即被确定下来:拔除术或者截冠术。第一步治疗计划根据全景片拟定,第二步根据CBCT确定。记录经拍摄CBCT后,选择使用截冠术的倾向因素。结果:手术方案是根据第二步治疗计划所执行的。113例(86.9%)样本的第一步治疗计划和第二步治疗计划是一致的,而经拍摄CBCT后的17例(13.1%)样本的治疗计划发生了改变。数据使用SPSS 22分析并应用5%的部分有统计学意义。下颌第三磨牙与下牙槽神经管直接接触时,会极大的影响治疗方案并最终选择使用截冠术。然而,直接接触并非一个充分的影响因素;另外,根的数量、根与神经管之间有无皮质骨、神经管是否位于根的凹陷处以及牙根与神经管接触的长度,也是对于选择截冠术的重要影响因素。结论:CBCT影响了13.1%的治疗计划。CBCT影像中观察到的下颌第三磨牙与神经管管腔的直接接触、神经管在根尖复合体附近弯曲或凹陷的位置、根与神经管之间有无皮质骨以及牙根与神经管接触的长度,对于决定使用截冠术是重要的影响因素。     

骨性Ⅱ类患者上气道形态及舌骨位置与颅颌面骨形态的相关性研究

目的　通过锥形束CT（CBCT）探究骨性Ⅱ类患者上气道形态及舌骨位置与颅颌面骨形态的相关性。方法  按纳入标准选取2016—2019年就诊于山西医科大学第一医院口腔科的60例患者的CBCT影像资料,并将其分为骨性Ⅰ类组、骨性Ⅱ类上颌前突组和骨性Ⅱ类下颌后缩组,每组20例。应用Dolphin11.95软件进行上气道的三维重建,测量颌骨形态、上气道形态及舌骨位置,对数据进行统计学分析。结果　上气道鼻咽段和腭咽段的容积及最小横截面积与SNA（蝶鞍中心、鼻根点及下齿槽座点所构成角）、ANS-PNS距（前后鼻棘点间距）呈正相关,骨性Ⅱ类上颌越前突上气道鼻咽段和腭咽段的容积及最小横截面积越大。上气道舌咽段和喉咽段的容积及最小横截面积与SNB（蝶鞍中心、鼻根点及下齿槽座点所构成角）、Go-Gn（下颌体长度）呈正相关,骨性Ⅱ类下颌越后缩上气道舌咽段和喉咽段的容积及最小横截面积越小。舌骨位置的测量指标H-VPS三组之间比较差异有统计学意义（P＜0.05）。结论　上气道各段的形态与其周围的颅颌面骨形态有着紧密的关联,上气道、颌骨及舌骨之间的关系密不可分。