J Am Dent Assoc. 2017 Aug;148(8):575-583. doi: 10.1016/j.adaj.2017.04.001. Epub 2017 May 19.
Clinicians generally use panoramic radiographic (PR) images to assess the proximity of the mandibular third molar to the inferior alveolar nerve (IAN). However, in cases in which a patient needs to undergo a third-molar extraction, many clinicians also assess computed tomographic (CT) images to prevent nerve damage.
Two of the authors independently searched MEDLINE (through PubMed), Cochrane Library, Scopus, and Ovid. The authors included randomized or nonrandomized longitudinal studies whose investigators had compared the number of IAN injuries after third-molar extraction in patients who had undergone preoperative CT with patients who had undergone only PR.
The authors analyzed the full text of 26 of the 745 articles they initially selected. They included 6 studies in the meta-analysis. Four of the studies had a high risk of bias, and the investigators of only 1 study had used blinding with the patients. The authors observed no statistically significant differences between groups related to the total number of nerve injuries (risk ratio, 0.96; 95% confidence interval, 0.50 to 1.85; P = .91). The prognosis of the injuries was similar for both groups.
Although having preoperative CT images might be useful for clinicians in terms of diagnosing and extracting mandibular third molars, having these CT images does not reduce patients' risk of experiencing IAN injuries nor does it affect their prognosis.
临床医生通常使用全景放射(PR)图像来评估下颌第三磨牙与下牙槽神经(IAN)的接近程度。但是,在患者需要进行第三磨牙拔除的情况下,许多临床医生还会评估计算机断层扫描(CT)图像以防止神经损伤。
两位作者独立检索了 MEDLINE(通过 PubMed)、Cochrane 图书馆、Scopus 和 Ovid。作者纳入了比较术前 CT 与仅 PR 检查的患者第三磨牙拔除后 IAN 损伤数量的随机或非随机纵向研究。
作者分析了他们最初选择的 745 篇文章中的 26 篇全文。meta 分析纳入了 6 项研究。其中 4 项研究存在高偏倚风险,只有 1 项研究的研究者对患者进行了盲法。两组之间与总神经损伤数量相关的差异无统计学意义(风险比,0.96;95%置信区间,0.50 至 1.85;P =.91)。两组的损伤预后相似。
虽然术前 CT 图像可能对临床医生诊断和拔除下颌第三磨牙有用,但这些 CT 图像并不能降低患者发生 IAN 损伤的风险,也不会影响其预后。