Department of Advanced General Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
J Adv Prosthodont. 2014 Jun;6(3):171-6. doi: 10.4047/jap.2014.6.3.171. Epub 2014 Jun 24.
The aim of this study was to determine the absolute value of the root/crown ratio (R/C ratio) using panoramic radiographs (PRGs) in a healthy Korean population.
In total, 99 patient radiographs (of 50 males and 49 females subjects; aged 16 to 24 years old) were examined, and 2,770 teeth were analyzed. Crown lengths and root lengths were measured with modified Lind's measurements using PACS tools by two examiners in two separate sessions two months apart. All data were analyzed using SPSS. The independent t-test was used to assess for gender differences, and the paired t-test was used to compare both arches with a significance level of P<.05.
The mean R/C ratios varied from 1.29 to 1.89 (male: 1.28-1.84; females: 1.31-1.94). The highest R/C ratios were recorded for the mandibular canines (1.89), followed by the maxillary canines (1.79). The lowest R/C ratios were recorded for the maxillary second molars (1.31). In comparison with the maxillary teeth (1.29-1.78), the mandibular teeth yielded the higher R/C ratio (1.47-1.89), and this difference was significant in the females (P<.05). The difference between the genders was not statistically significant, except for the maxillary central incisors, mandibular canines and mandibular first premolars.
These data may enhance the understanding of the clinical R/C ratio as a useful guideline for determining the status of teeth and the ethnic difference.
本研究旨在通过全景片（PRG）确定健康韩国人群的根冠比（R/C 比）的绝对值。
共检查了 99 例患者的放射照片（50 名男性和 49 名女性受试者；年龄 16 至 24 岁），分析了 2770 颗牙齿。使用 PACS 工具通过两位检查者在相隔两个月的两次独立检查中，对牙冠长度和牙根长度进行改良的 Lind 测量。所有数据均采用 SPSS 进行分析。采用独立 t 检验评估性别差异，采用配对 t 检验比较上下颌弓，以 P<.05 为显著性水平。
R/C 比值的平均值从 1.29 到 1.89（男性：1.28-1.84；女性：1.31-1.94）。下颌尖牙的 R/C 比值最高（1.89），其次是上颌尖牙（1.79）。上颌第二磨牙的 R/C 比值最低（1.31）。与上颌牙齿（1.29-1.78）相比，下颌牙齿的 R/C 比值更高（1.47-1.89），且女性之间存在显著差异（P<.05）。除上颌中切牙、下颌尖牙和下颌第一前磨牙外，男女之间的差异无统计学意义。
这些数据可能有助于理解临床 R/C 比作为确定牙齿状况和种族差异的有用指南。
