Shigeeda Toru
Department of Orthodontics, Nihon University School of Dentistry.
J Oral Sci. 2014 Mar;56(1):59-65. doi: 10.2334/josnusd.56.59.
This study aimed to investigate a causal relationship between the stability of orthodontic anchor screws (screws) and the degree of their proximity to the root (root proximity) using mobility test device (Periotest) and cone-beam computed tomography (CBCT). In total, 165 (diameter 1.6 mm; length 8 mm) screws in 58 patients (average age, 24.4 ± 8.5 years) were evaluated. After screw placement, CBCT was used for diagnostic imaging of the area around the site. Root proximity was evaluated and categorized into three groups: A, no contact; B, single contact; and C, multi-contact. The Periotest value was used to assess screw stability. The screw failure rate according to root proximity significantly differed between categories A and C. In addition, failure rate significantly differed between mandibular screws with and without root contact. Periotest values in categories A and C were significantly higher in the mandible than in the maxilla. Mandibular screws had greater mobility than maxillar screws, even when the screw avoided root contact. The lower stability of mandibular screws with root contact might be related to their greater mobility.
本研究旨在使用松动度测试装置（牙动度测试仪）和锥形束计算机断层扫描（CBCT），探讨正畸支抗螺钉（螺钉）的稳定性与其与牙根的接近程度（牙根接近度）之间的因果关系。共评估了58例患者（平均年龄24.4±8.5岁）的165颗螺钉（直径1.6 mm；长度8 mm）。螺钉植入后，使用CBCT对植入部位周围区域进行诊断成像。评估牙根接近度并将其分为三组：A组，无接触；B组，单接触；C组，多接触。使用牙动度测试仪值评估螺钉稳定性。根据牙根接近度分类，A组和C组的螺钉失败率有显著差异。此外，下颌有牙根接触和无牙根接触的螺钉失败率也有显著差异。A组和C组在下颌的牙动度测试仪值显著高于上颌。下颌螺钉即使避免与牙根接触，其松动度也比上颌螺钉大。下颌有牙根接触的螺钉稳定性较低可能与其更大的松动度有关。
