管电压、管电流和相邻钛种植体对锥形束CT评估根管治疗后牙根纵裂的影响

Influence of Tube Voltage,Tube Current,and Adjacent Titanium Implant on Detection of Vertical Root Fractures after Root Canal Therapy using Cone-beam Computed Tomography

目的:探究不同管电压、管电流和不同数目相邻钛种植体对锥形束CT(cone-beam computed tomography,CBCT)评估根管治疗后牙根纵裂(vertical root fracture,VRF)的影响。方法:将20颗单根管下颌前磨牙体外完成根管预备后随机选择10颗模拟VRF。每颗牙根管内放入牙胶尖并放置在人下颌骨标本的右下第一前磨牙牙槽窝内,在不同管电压(60 kV、80 kV)、不同管电流(3 mA、6 mA和10 mA)和不同数目相邻钛种植体(对照组、1颗相邻钛种植体和2颗相邻钛种植体)的条件下,共采集360例CBCT图像数据,5名观察者均采用5分评分量表判读所有图像。使用双因素方差分析和Turkey事后检验比较灵敏度、特异度和ROC曲线下面积(area under the ROC curve,AUC)。结果:根管治疗后VRF诊断的特异度受管电压和管电流的影响,当管电流一定,管电压从60 kV增至80 kV时,特异度增加,有统计学意义(P<0.05),当管电压一定时,管电流从3 mA增至6 mA或10 mA时,特异度增加,有统计学意义(P<0.05),而相邻钛种植体数目对诊断无影响。结论:管电压的增加有利于根管治疗后VRF的诊断,但基于合理可行尽量低(as low as reasonably achievable,ALARA)的原则,在不影响诊断的前提下,增加管电压的同时,尽量选择较低的管电流;不同数目相邻钛种植体并不会影响CBCT对根管治疗后VRF的评估。

Objective:To investigate the effect of tube voltage,tube current,and different numbers of adjacent titanium implants on the assessment of vertical root fracture(VRF)after root canal therapy by cone beam computed tomography(CBCT).Methods:Twenty single rooted mandibular premolars were collected and 10 were randomly induced VRF after root canal preparation in vitro.Each tooth canal was placed with a gutta-percha and each tooth was placed in the alveolar socket of right lower first premolar of the human mandible specimen.A total of 360 images were acquired using CBCT at different tube voltages(60 kV and 80 kV),different tube currents(3 mA,6 mA,and 10 mA),and different adjacent titanium implants(control group,1 adjacent titanium implant,and 2 adjacent titanium implants).Images were interpreted by 5 observers on a 5-point scoring scale for all images,and sensitivity,specificity,and area under the ROC curve(AUC)were compared using 2-way ANOVA and the turkey post hoc test.Results:The specificity of VRF diagnosis after root canal treatment was affected by tube voltage and tube current,which increased to statistical significance when the tube current was certain,tube voltage increased from 60 kV to 80 kV(P<0.05),and when the tube voltage was certain,tube current increased from 3 to 6 mA or 10 mA(P<0.05),whereas the number of adjacent titanium implants had no influence on diagnosis.Conclusion:An increase in the tube voltage is beneficial for the diagnosis of VRF after root canal treatment,but based on the as low as reasonably achievable(ALARA)principle,without compromising the diagnosis,while increasing the tube voltage,try to select a lower tube current.Different numbers of adjacent titanium implants did not affect the evaluation of VRF after root canal treatment by CBCT.