Brasil Danieli Moura, Nascimento Eduarda H L, Gaêta-Araujo Hugo, Oliveira-Santos Christiano, Maria de Almeida Solange
PhD Student, Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, Brazil.
PhD Student, Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, Brazil.
J Oral Maxillofac Surg. 2019 Oct;77(10):1968-1974. doi: 10.1016/j.joms.2019.03.041. Epub 2019 Apr 11.
Preoperative recognition of the relative position of the mandibular third molars may contribute to more reliable treatment planning, avoiding injuries and decreasing surgical and recovery times. The research questions for this study were as follows: 1) Is panoramic radiography (PR) equivalent to cone-beam computed tomography (CBCT) in determining the degree of mandibular third molar impaction? 2) For PR, is the external oblique ridge a more reliable reference to determine the degree of mandibular third molar impaction?
This retrospective case-series study assessed whether the imaging modalities (primary predictor variable) are equivalent in determining the degree of impaction of third molars (primary outcome variable) according to the parameters of the Pell and Gregory classification. Two oral and maxillofacial radiologists evaluated PR and CBCT images presenting at least 1 mandibular third molar. The degrees of impaction related to the ascending ramus and related to the external oblique ridge (secondary outcome variables) also were assessed. The agreement rates between PR and CBCT were presented, and the imaging modalities were compared by the McNemar-Bowker test (α = .05).
A total of 173 patients were included (66 male and 107 female patients). Among these patients, 313 mandibular third molars were assessed. In relation to the occlusal plane, the agreement rate between PR and CBCT was 82.1% for Pell and Gregory class A, 90.5% for class B, and 65.6% for class C (P = .116). The overall agreement rate between the classifications in relation to the mandibular ramus on PR and CBCT ranged from 66.8% (considering the ascending ramus, P < .001) to 76.4% (considering the external oblique ridge, P < .001).
PR performs similarly to CBCT in the classification of impaction in relation to the occlusal plane. However, PR shows a tendency to underestimate the space for accommodation of the third molar compared with CBCT. Furthermore, the external oblique ridge is not a reliable alternative landmark on PR.
术前识别下颌第三磨牙的相对位置有助于制定更可靠的治疗计划，避免损伤并缩短手术和恢复时间。本研究的研究问题如下：1）全景放射摄影（PR）在确定下颌第三磨牙阻生程度方面是否等同于锥形束计算机断层扫描（CBCT）？2）对于PR，外斜线是否是确定下颌第三磨牙阻生程度更可靠的参考？
本回顾性病例系列研究根据佩尔和格雷戈里分类参数评估成像方式（主要预测变量）在确定第三磨牙阻生程度（主要结局变量）方面是否等效。两名口腔颌面放射科医生评估了至少有1颗下颌第三磨牙的PR和CBCT图像。还评估了与升支相关以及与外斜线相关的阻生程度（次要结局变量）。给出了PR和CBCT之间的一致率，并通过麦克内马尔-鲍克检验（α = 0.05）比较成像方式。
共纳入173例患者（66例男性和107例女性患者）。在这些患者中，评估了313颗下颌第三磨牙。关于咬合平面，PR和CBCT之间佩尔和格雷戈里A类的一致率为82.1%，B类为90.5%，C类为65.6%（P = 0.116）。PR和CBCT上与下颌升支相关分类的总体一致率在66.8%（考虑升支，P < 0.001）至76.4%（考虑外斜线，P < 0.001）之间。
PR在与咬合平面相关的阻生分类方面与CBCT表现相似。然而，与CBCT相比，PR有低估第三磨牙容纳空间的趋势。此外，外斜线在PR上不是可靠的替代标志。
