Nogami Shinnosuke, Yamauchi Kensuke, Bottini Gian Battista, Kouketsu Atsumu, Otake Yoshio, Sai Yuko, Kataoka Yoshihiro, Miyashita Hitoshi, Takahashi Tetsu
Division of Oral and Maxillofacial Surgery, Department of Oral Medicine, and Surgery, Tohoku University Graduate School of Dentistry, Aoba-ku, Sendai, Miyagi, Japan.
Department of Oral and Maxillofacial Surgery, Paracelsus Medical University Salzburg, Salzburg, Austria.
J Craniofac Surg. 2018 Oct;29(7):e713-e717. doi: 10.1097/SCS.0000000000004961.
The relationship between impacted mandibular third molars with angle and condylar fractures is subject of many publications, yet their conclusions differ widely, hence the authors wanted to investigate this topic in their patients.
The authors designed a retrospective study including 241 patients who presented with angle and/or mandibular condyle fractures over a 13-year period at the authors' institution. The study variable was the presence/absence of third molars. The authors used the Pell and Gregory system to classify their position, whereas the angulation was classified using Archer classification. The outcome variables were the presence of angle and condylar fractures. Other study variables included fracture etiology.
Assaults were the most frequent cause of angle fractures (62.7%), whereas falls were mostly responsible for condylar fractures (79.6%). Angle fractures were mostly isolated (66.3%), whereas condylar fractures were mostly associated with other fractures (62.6%). The majority of the angle fractures occurred in patients with third molars (63.6%), on the contrary the majority of the condylar fractures occurred in patients without mandibular third molars (78.3%). Angle fractures were mostly associated with fully erupted or superficially impacted third molars (90,9%). Finally in the presence of mesioangulated third molars, condylar fractures did not happen in 83.8% of patients.
According to the authors' findings, fully erupted or superficially impacted mandibular third molars are a risk factor for angle fractures but at the same time a protective factor for the condyle. On the contrary, the absence of mandibular third molars "strengthens" the angle and represents a risk factor for condylar fractures.
下颌第三磨牙阻生与髁突骨折之间的关系是众多出版物的主题，但其结论差异很大，因此作者希望在其患者中研究这一课题。
作者设计了一项回顾性研究，纳入了在作者所在机构13年期间出现下颌角和/或髁突骨折的241例患者。研究变量为第三磨牙的有无。作者使用佩尔和格雷戈里系统对其位置进行分类，而角度则使用阿彻分类法进行分类。结果变量为下颌角和髁突骨折的存在情况。其他研究变量包括骨折病因。
袭击是下颌角骨折最常见的原因（62.7%），而跌倒主要导致髁突骨折（79.6%）。下颌角骨折大多为孤立性骨折（66.3%），而髁突骨折大多与其他骨折相关（62.6%）。大多数下颌角骨折发生在有第三磨牙的患者中（63.6%），相反，大多数髁突骨折发生在没有下颌第三磨牙的患者中（78.3%）。下颌角骨折大多与完全萌出或浅位阻生的第三磨牙相关（90.9%）。最后，在存在近中倾斜第三磨牙的情况下，83.8%的患者未发生髁突骨折。
根据作者的研究结果，完全萌出或浅位阻生的下颌第三磨牙是下颌角骨折的危险因素，但同时也是髁突的保护因素。相反，下颌第三磨牙的缺失“强化”了下颌角，是髁突骨折的危险因素。
