Objective: To study the clinical efficacy of digital design combined with three-dimensional (3D) printing model minimally invasive extraction of complex impacted mandibular third molars. Methods: Eight patients who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from April 2023 to March 2024 were included, including 3 males and 5 females, aged from 27 to 57 years old. The impacted mandibular third molars of all patients were closely related to the mandibular canal, and part of the dental tissue entered the mandibular canal. Preoperative digital design was used to simulate the intraoperative tooth segmentation and bone removal operation of the power system and the segmented tooth dislocation path, and analyze the tooth extraction resistance. The mandibular teeth, mandibular canal and mandibular model were three-dimensionally printed using light-curing resin inkjet. During the operation, an endoscope was used combined with the 3D printed model to minimally invasively extract the impacted mandibular third molar. Quantitative sensory testing of the patient's lower lip skin on the operated side was performed before surgery, 2 days after surgery, and 7 days after surgery. Clinical data such as operation time were collected. A paired sample t test was performed on the 2 and 7 days postoperative data and the preoperative data to compare the data differences. Results: All 8 patients successfully completed preoperative design, model printing and minimally invasive surgery. The number of teeth segmented in the preoperative design was (4.4±1.3), and the number of teeth segmented in the actual operation was (4.0±1.1). The operation time was (33.3±13.0) min. None of the patients had postoperative numbness of the lower lip or other postoperative complication. It was observed endoscopically that the inferior alveolar neurovascular bundle was exposed in the extraction socket during the operation. The patient's pressure pain threshold 2 days after surgery (0.601±1.170) was significantly lower than before surgery (1.251±1.109) (t=2.83, P=0.025). Conclusions: For complicated impacted mandibular third molars, digital design combined with 3D printing model can be used to perform minimally invasive extraction with the assistance of an endoscope.
目的： 研究数字化设计结合内镜和三维打印模型微创拔除复杂下颌阻生第三磨牙的临床疗效。 方法： 纳入2023年4月至2024年3月就诊于北京大学口腔医学院·口腔医院口腔颌面外科门诊的患者8例，其中男性3例，女性5例，年龄为27~57岁。所有患者的下颌阻生第三磨牙均与下颌管关系密切，且部分牙体组织进入下颌管内。术前通过数字化设计，模拟术中动力系统分牙去骨操作以及牙齿分块脱位路径，分析拔牙阻力。采用光固化树脂喷墨三维打印下颌牙、下颌管及颌骨模型，术中使用内镜结合三维打印模型，微创拔除下颌阻生第三磨牙。术前、术后2 d、术后7 d对患者手术侧进行下唇皮肤定量感觉测试，采集手术时间等临床数据，并使用配对样本t检验对比分析术后2、7 d与术前的数据差异。 结果： 8例患者均顺利完成术前设计、模型打印及微创手术。术前设计牙齿分块数为（4.4±1.3）块，实际手术操作中牙齿分块数为（4.0±1.1）块；手术时间为（33.3±13.0）min，患者均无下唇麻木等术后并发症。内镜观察到术中下牙槽神经血管束均暴露于拔牙窝内。术后2 d患者的压力痛觉阈值（0.601±1.170）显著低于术前（1.251±1.109）（t=2.83，P=0.025）。 结论： 对复杂下颌阻生第三磨牙，可采用数字化设计结合三维打印模型，在内镜辅助下进行微创拔除。.