Department of Stomatology, Changzhi People's Hospital, Shanxi, China.
Department of Oral and Maxillofacial Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.
Technol Health Care. 2023;31(S1):497-504. doi: 10.3233/THC-236043.
Retromolar canal (RMC) arises from the mandibular canal (MC) behind the second or third molar and travels anterosuperiorly to a retromolar foramen (RMF). RMCs and RMFs have generally been ignored in anatomical textbooks and have rarely been reviewed or studied in the anatomical and dental literature until the last decades.
This study aimed to characterize RMF in a Chinese population concerning its incidence, origin, and classification via anatomical study and periapical radiography.
123 dry adult Chinese mandibles were collected to observe the incidence of RMFs. RMFs were determined using a steel wire 0.5 mm in diameter. The passways or origins of the retromolar canal (RMC) were determined and classified via periapical radiography. For each RMF, two dentists independently measured the diameter and its distances to the lingual cortex, the buccal cortex, and the distal edge of the last tooth (or the alveolar fossa) using a vernier caliper.
The incidence of RMFs was 31.71%. The average RMF diameter was 0.78 ± 0.27 mm. From RMF, the distance was 4.27 ± 1.87 mm to the lingual cortex, 8.61 ± 2.23 mm to the buccal cortex, and 7.84 ± 3.87 mm to the distal edge of the last tooth (or the alveolar fossa). RMCs were classified into MC type originating from the mandibular canal and AF type originating from the alveolar fossa. The diameters of MC ones were more significant than those of AF ones. There was no apparent correlation between the existence of the third molar and the presence of an RMF.
The incidence of RMFs in Chinese may be about one-third, which is a potential factor in the onset of surgery accidents. RMCs can be classified into two types by their origins. One of them is MC, which originates from the mandibular canal, and the other is AF, which originates from the alveolar fossa.
Retromolar 运河 (RMC) 起源于下颌管 (MC) 后面的第二或第三磨牙，并向前上运行至 Retromolar 孔 (RMF)。直到最近几十年，RMC 和 RMF 才在解剖学教科书中被普遍忽略，并且在解剖学和牙科文献中很少被回顾或研究。
本研究旨在通过解剖学研究和根尖放射线照相术来描述中国人群中 RMF 的特征，包括其发生率、起源和分类。
收集 123 例成人干燥中国下颌骨，观察 RMF 的发生率。使用直径为 0.5 毫米的钢丝确定 RMF。通过根尖放射线照相术确定和分类 Retromolar 运河 (RMC) 的通道或起源。对于每个 RMF，两位牙医使用游标卡尺独立测量其直径及其与舌侧皮质、颊侧皮质和最后一颗牙齿（或牙槽窝）远端边缘的距离。
RMF 的发生率为 31.71%。平均 RMF 直径为 0.78 ± 0.27 毫米。从 RMF 到舌侧皮质的距离为 4.27 ± 1.87 毫米，到颊侧皮质的距离为 8.61 ± 2.23 毫米，到最后一颗牙齿（或牙槽窝）远端边缘的距离为 7.84 ± 3.87 毫米。RMC 分为起源于下颌管的 MC 型和起源于牙槽窝的 AF 型。MC 型的直径大于 AF 型。第三磨牙的存在与 RMF 的存在之间没有明显的相关性。
中国人 RMF 的发生率约为三分之一，这是手术事故发生的潜在因素。RMC 可根据其起源分为两种类型。一种是起源于下颌管的 MC，另一种是起源于牙槽窝的 AF。
