Incremental lines in root cementum of human teeth —A reliable age marker?
Introduction
Teeth are the most durable structures in human and animal bodies, and they are sometimes the only and often the best-preserved remains of corpses. Therefore, forensic medicine and paleoanthropology evidently have a great interest in deducing from these remains as much information as possible about the individual.
When slices are cut from the roots of human teeth and ground to a thickness of about 80–100 μm, thin alternating dark and light lines become visible in the band of cementum under the light microscope. Their sometimes nearly concentric appearance is reminiscent of the annual rings of trees. Since there is also a life-long apposition of root cementum in teeth (Zander and Hürzeler, 1958), it seemed likely that the number of these lines might be age-dependent (Stott et al., 1982). This would be of particular interest, because counting lines in root cementum would be the first method to determine the real chronological age without being influenced by the maturation state of the individual. Numerous investigators obtained different results when using teeth of known age to check the reliability of this method for age determination. Some were not able to find any connection between the age and the number of lines (Lipsinic et al., 1986; Lucas and Loh, 1986; Miller et al., 1988), while others found only a moderate correlation between the two parameters and remained skeptical (Jankauskas et al., 2001; Kvaal and Solheim, 1995; Stein and Corcoran, 1994). However, many of the investigators found a good correlation between the number of lines in cementum and the age of the tooth (Charles et al., 1986; Condon et al., 1986; Großkopf, 1990; Stott et al., 1982). Moreover, very recent publications have proposed cementum line counting as a feasible method for determining the age-at-death of an individual (Kagerer and Grupe, 2001; Rao and Rao, 1998; Wittwer-Backofen et al., 2004). But an increasing divergence between predicted and actual age was found with increasing age (Kvaal and Solheim, 1995; Stein and Corcoran, 1994). Pilloud (2004) found a correlation () between counted lines and known age in a group of individuals aged from 21 to 45 yrs but no correlation () in a group of individuals aged from 57 to 90 yrs.
Some critical questions still remain unanswered. The ultra-structural nature of these lines in human root cementum is still unclear (Renz et al., 1997) e.g., and the underlying biological rhythm is not understood.
In our study, we counted cementum lines in different sections from the middle third of the root of the same tooth. Since annually recurring external factors leaving their imprint in dental root cementum should be visible in every part of it, the same number of cementum lines should be found in different sections of the same root and, of course, in each region of these sections. This alone would justify the terms “cementum rings” or “cemental annulations”. If the numbers of lines varied in different regions of root cementum of the same tooth, there would be no way to determine which line number is the “correct” one, and counting lines in root cementum as a method for age determination would be at least dubious.
Section snippets
Preparation of sections
Eight premolars P1 and P2 (T1=14; T2=15; T3=44; T4=45; T5=34; T6=35; T7=45; T8=14), extracted for clinical reasons from patients of known age (T1=90 yrs; T2=48 yrs; T3=50 yrs; T4=71 yrs; T5=50 yrs; T6=32 yrs; T7=69 yrs; T8=65 yrs), were collected and stored in 5% formaldehyde in water. Attention was paid to the integrity of root cementum after extraction. Premolars from patients with obvious periodontal problems were not used in this study, and this was the only criterion for excluding teeth; no other
Difficulties in preparation and evaluation
Publications on age determination by counting cementum lines suggest this method would be technically most simple and unproblematic. We could not in the least confirm this view. We would therefore like to direct some attention to the description of specimen preparation and, particularly, to the appearance of the lines in dental root cementum and the difficulties involved in counting these lines.
During sectioning or grinding, some of the sections broke completely or parts of the cementum broke
Discussion
If we assume that root cementum of teeth is formed in an annual rhythm and that the microscopically visible lines in tooth sections reflect this annual rhythm, we would expect to find a comparable number of lines in all regions of the root of the same tooth or at least in a definable region where such regular cementum formation would occur. All studies on age determination using cementum lines are based on this assumption and, with the aid of statistics, conclude from the number of counted
Acknowledgements
We thank Kurt W. Alt and Werner Götz for helpful discussions, Vanessa Schaefer for collecting the teeth and preparing the sections, Anne Kähler for counting (observer 2) and Joanne Weirowski for her help with the English manuscript.
References (23)
- et al.
Correlation between age and thickness of cementum in impacted teeth
Oral Surg.
(1974) - et al.
Incremental lines of dental cementum in biological age estimation
Homo
(2001) - et al.
Age-at-death diagnosis and determination of life-history parameters by incremental lines in human dental cementum as an identification aid
Forensic Sci. Int.
(2001) The biological basis for seasonal increments in dental cementum and their application to archaeological research
J. Archaeol. Sci.
(1994)- et al.
Paradicular cementum deposition as a criterion for age estimation in human beings
Oral Surg. Oral Med. Oral Path.
(1994) - et al.
Cementum annulation and age determination in Homo sapiens: I. tooth variability and observer error
Am. J. Phys. Anthropol.
(1986) - et al.
Cementum annulation and age determination in Homo sapiens: II. estimates and accuracy
Am. J. Phys. Anthropol.
(1986) Individualaltersbestimmung mit Hilfe von Zuwachsringen im Zement bodengelagerter menschlicher Zähne
Z. Rechtsmed.
(1990)- et al.
Incremental lines in human dental cementum in relation to age
Eur. J. Oral Sci.
(1995) - et al.
Evaluation of preparation, staining and microscopic techniques for counting incremental lines in cementum of human teeth
Biotech. Histochem.
(1996)
Life history variables preserved in dental cementum microstructure
Science
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