Mandibular molar C-shaped root canals in 5th millennium BC China. (September 2020)

• Record Type: Journal Article
• Authors: Ren, Hui Ying; Zhao, Yong Sheng; Yoo, Yeon-Jee; Zhang, Xiao Wen; Fang, Hui; Wang, Fen; Perinpanayagam, Hiran; Kum, Kee-Yeon; Gu, Yu
• Is Part Of: Archives of oral biology. Volume 117(2020)
• Publication Date: 2020-09
• Subjects: micro-CT microcomputed tomography -- CBCT cone-beam computed tomography -- C1 Category 1 -- C2 Category 2 -- C3 Category 3 -- C4 Category 4 -- C5 Category 5; C-shaped root canal -- Cone-Beam computed tomography -- Craniofacial bone remains -- Mandibular second molar; Mouth -- Periodicals; Mouth -- Diseases -- Periodicals; Dentistry -- Periodicals; Electronic journals; 617.6005
• DOI: 10.1016/j.archoralbio.2020.104773
• Languages: English
• ISSNs: 0003-9969

Abstract

Highlights: Anatomic study of a prehistoric Chinese population from the Neolithic era. High prevalence of C-shaped canals in the mandibular second molars. C-shaped canals and their variants of prehistoric and contemporary clinical cases. Abstract: Objective: The aim of this study was to analyze the occurrence and variations in C-shaped canals in ancient Chinese teeth and compare the differences of these features between ancient and age-matched modern populations. Design: Approximately 5000-year-old craniofacial bone remains were collected from the fossils of 38 individuals (total: 68 mandibular second molars) excavated from the Jiaojia site. The control group comprised of an equal number of randomly selected modern samples. We used cone-beam computed tomography to scan the mandible along the apex-crown axis and analyzed the canal morphology, based on Fan's categorization criterion, at 2 mm, 5 mm, and 8 mm to the apical level. Grooves on the lingual and buccal sides were also recorded. Results: The proportion of C-shaped roots among ancient samples on the left and right sides were 48.57 % (17/35 teeth) and 54.55 % (18/33 teeth), respectively, and 51.47 % (35/68 teeth) in the total sample. Conversely, in the control group, 44.12 % (15/34) and 38.24 % (13/34) occurred on the left and right sides, respectively, and 41.18 % (28/68) in the total sample. Among the C-shaped canals from the Jiaojia site samples, the classification type changed between two adjacent levels in 84.31 % of samples. Approximately 35 (51.5 %) teeth had a fused root, 20 (29.41 %) had one shallow buccal and one deep lingual groove. The occurrence of C-shape variation was not significantly correlated with time ( p ＞0.05). Conclusions: This study identified a high rate of C-shaped root canals among individuals of Jiaojia who lived approximately 5000 years ago.