Yadav Sumit, Palo Ledjo, Mahdian Mina, Upadhyay Madhur, Tadinada Aditya
Assistant professor, Division of Orthodontics, Health Center, University of Connecticut, Farmington, Conn.
Postgraduate student, School of Dental Medicine, Health Center, University of Connecticut, Farmington, Conn.
Am J Orthod Dentofacial Orthop. 2015 Mar;147(3):339-44. doi: 10.1016/j.ajodo.2014.11.017.
The temporomandibular joint (TMJ) is a complex joint that often develops degenerative joint disease. Clinical examination alone cannot usually diagnose this accurately, and a radiographic examination complements and aids in diagnosis and treatment. The osseous components of the TMJ complex are best imaged using computed tomography. The evolution of cone-beam computed tomography (CBCT) offers a low radiation dose and a high spatial resolution alternative and is becoming the imaging modality of choice for the TMJ. To further reduce the dose and yet not compromise the diagnostic task at hand, some alternative rotation acquisition protocols are available but have not been adequately evaluated. The aim of this study was to evaluate the diagnostic efficacy of 2 CBCT acquisition protocols to detect degenerative changes associated with the TMJ complex.
Thirty-four TMJs, from 17 dry human skulls, were obtained from the anatomy department at the School of Dental Medicine of the University of Connecticut. The sample consisted of complete dentate and partially dentate skulls with no identifiable markers such as age, sex, or ethnicity. Small and large lesions simulating early and established arthritic changes were created on the mandibular condyle. Each defect was randomly created on the medial pole, articulating surface, or lateral pole. After simulating the articular disc with rubber dam material, the condyle and the glenoid fossa were articulated and positioned in place by a rubber band. The skulls were scanned by using an Accuitomo CBCT scanner (J. Morita Corp, Kyoto, Japan) with 180° and 360° rotation protocols. Two operators scored the lesions and compared the results to the gold standard, which was the master list of where the lesions were made on the condyles.
On the 102 randomly selected sites, 39 large and 33 small lesions were made, and the rest of the sites had no lesions. The detection rates for areas with large lesions and areas with no lesions were 100% between the examiners. However, of the 33 small lesions, each examiner was able to identify 32 of them with the 360° scans: a 97.4% detection rate when compared with the gold standard. With the 180° scan, 94.9% of the small lesions were detected when compared with the gold standard, and 96.9% were detected with the 360° scan. The overall interexaminer reliability was over 90% for both imaging protocols (Cronbach's alpha, 92.4% for 180° and 97% for 360°).
Based on the results of this study, the 180° CBCT acquisition protocol can detect small and large arthritic lesions with high reliability and is comparable with the 360° spin acquisition.
颞下颌关节（TMJ）是一个复杂的关节，常发生退行性关节疾病。仅靠临床检查通常无法准确诊断，而影像学检查可辅助诊断和治疗。颞下颌关节复合体的骨性结构最好用计算机断层扫描成像。锥形束计算机断层扫描（CBCT）的发展提供了低辐射剂量和高空间分辨率的替代方案，正成为颞下颌关节成像的首选方式。为了进一步降低剂量且不影响手头的诊断任务，有一些替代旋转采集方案可供使用，但尚未得到充分评估。本研究的目的是评估两种CBCT采集方案检测与颞下颌关节复合体相关退行性改变的诊断效能。
从康涅狄格大学牙科学院解剖学系获取17个干燥人类头骨的34个颞下颌关节。样本包括完整牙列和部分牙列的头骨，没有年龄、性别或种族等可识别标记。在下颌髁突上制造模拟早期和已确诊关节炎改变的大小病变。每个缺损随机制造在内侧极、关节面或外侧极。用橡胶坝材料模拟关节盘后，用橡皮筋将髁突和关节窝连接并固定到位。使用Accuitomo CBCT扫描仪（日本京都森田公司）对这些头骨进行180°和360°旋转方案扫描。两名操作人员对病变进行评分，并将结果与金标准进行比较，金标准是髁突上病变位置的主列表。
在102个随机选择的部位，制造了39个大病变和33个小病变，其余部位无病变。检查人员之间对有大病变区域和无病变区域的检测率均为100%。然而，在33个小病变中，每位检查人员在360°扫描中能够识别其中32个：与金标准相比，检测率为97.4%。在180°扫描中，与金标准相比，94.9%的小病变被检测到，360°扫描中96.9%被检测到。两种成像方案的检查人员间总体可靠性均超过90%（Cronbach's alpha，180°为92.4%，360°为97%）。
基于本研究结果，180°CBCT采集方案能够以高可靠性检测大小关节炎病变，与360°旋转采集相当。
