Kullman L, Johanson G, Akesson L
Department of Oral Diagnostics, Faculty of Odontology, Huddinge, Sweden.
Swed Dent J. 1992;16(4):161-7.
Methods based on radiological, distinguishable stages of tooth formation can be used to estimate chronological age in young persons. The best precision and accuracy of these methods of age estimation is obtained when many teeth are under development and when the individual growth rate is rapid. That is during early years-in childhood. After an age of about 14 years it becomes more difficult since all permanent teeth but the wisdom teeth have completed their development and only these remain to be used for age estimation. The aim of this study was to examine the radiological development of the root of the mandibular third molar and to explore its usefulness in age estimation. Also the differences between two independent observers were studied. The observers classified the development of the mandibular third molars, as seen in a panoramic radiograph, into seven defined stages. The two observers agreed in about 84% of the cases in their registration of the different stages, but a significant difference was found between the observers. The mineralisation of the third molar's root was found to start at the age of 15 years and the root was fully formed at about 20 years. Some minor differences were found between sexes in the time sequence of the mineralisation. The study also shows that there is a rather low precision in the age estimation with the method used. In general, a standard deviation of about 1 to 2 years was found around the mean age of the different developmental stages.
基于牙齿发育放射学上可区分阶段的方法可用于估计年轻人的实足年龄。当许多牙齿处于发育阶段且个体生长速度较快时，即童年早期，这些年龄估计方法能获得最佳的精度和准确性。在大约14岁之后，由于除智齿外的所有恒牙都已完成发育，只剩下智齿可用于年龄估计，因此难度增大。本研究的目的是检查下颌第三磨牙牙根的放射学发育情况，并探讨其在年龄估计中的作用。同时还研究了两位独立观察者之间的差异。观察者将全景X线片中可见的下颌第三磨牙发育情况分为七个明确阶段。两位观察者在不同阶段的记录中约84%的情况一致，但观察者之间存在显著差异。发现第三磨牙牙根的矿化始于15岁，约20岁时牙根完全形成。在矿化的时间顺序上，两性之间存在一些细微差异。该研究还表明，所使用的年龄估计方法精度相当低。总体而言，在不同发育阶段的平均年龄周围发现约1至2年的标准差。
