Incremental lines in root cementum of human teeth: An approach to their role in age estimation using polarizing microscopy

Objectives: Cementochronology based on annual deposition of acellular cementum is acknowledged for its superior performance for estimating age-at-death but is also disregarded because of its suspicious effectiveness. This article aims to provide a standardized framework for the validation of the technique and to define and test cementochronology's performance and limitations. Materials and methods:To determine the boundaries of the cementum aging technique, we applied a certified protocol on a sample of 200 healthy canines from individuals of known age, sex, postmortem, and inhumation intervals from anthropological and anatomical collections. We scored readability and preservation of cementum and measured the agreement between estimates, i.e., the precision, and assessed the quality of the accordance between estimates and chronological age, i.e., the accuracy. To investigate the applicability on ancient material, 200 additional canines extracted from archeological assemblages were included. Accuracy and precision were analyzed for each age group in considering postmortem intervals and taphonomical conditions.Results: A strong correlation was found between chronological age and estimates (r = .927; p = .000) but results reveal an association between readability of incremental lines and chronological age (p < .05) and a notable difference in both precision and accuracy between individuals under and over 50 years. Results also demonstrate that taphonomy can be a serious obstacle increasing imprecision by a factor of three.Discussion: Improperly adopted, cementochronology can lead to precise but inaccurate estimations. If methodological, physiological, and taphonomical factors are taken into account, then, and only then, cementochronology will serve as a versatile and powerful tool for age-at-death estimation. K E Y W O R D Sage-at-death estimation, cementochronology, dental cementum, taphonomy

Section: Resultssupporting

confidence: 91%

Age at death estimation by cementochronology: Too precise to be true or too precise to be accurate?

Bertrand

Cunha

Bécart

et al. 2019

“…TCA incremental bands under the lens of a light microscope, are revealed as alternating dark and translucent (see Grosskopf & McGlynn, ; Kagerer & Grupe, ; Stott, Sis, & Levy, ; Wittwer‐Backofen, ; Wittwer‐Backofen, Gampe, & Vaupel, ) (Figure ). The appositional growth of each of the two bands is driven by a robust circannual (literally, about a year) biological rhythm, which has been confirmed in many studies in population samples of known‐age individuals from different ethnic groups (Aggarwal, Saxena, & Bansal, ; Avadhani, Tupkari, Khambaty, & Sardar, ; Bojarun, Jankauskas, & Garmus, ; Broucker, Colard, Penel, Blondiaux, & Naji, ; Charles, Condon, Cheverud, & Buikstra, ; Dias, Beaini, & Melani, ; Gocha & Schutkowski, ; Gupta, Kaur, Shankari, Jawanda, & Sahi, ; Kagerer & Grupe, ; Kasetty, Rammanohar, & Raju Ragavendra, ; Meinl et al, ; Naji et al, ; Obertová & Francken, ; Pundir, Saxena, & Aggrawal, ; Stott et al,; Wittwer‐Backofen et al, ). As such, the close relationship between TCA estimated age and CA is not disputed.…”

Section: Tooth Cementum Annulationsmentioning

confidence: 64%

Differences between biological and chronological age‐at‐death in human skeletal remains: A change of perspective

Couoh

2017

TCA can be used to estimate CA and its differences with BA, being less than 10 years, are similar to those found in living populations. Differences between CA and BA are due to intra-population variability, which could be the consequence of individual differences in aging. More research is needed to have confidence that under- and overestimations of BA are indicators of aging variability at the level of the individual.

“…Moreover, usefulness of TCA should be explored in historical/ancient samples coming from different environmental and taphonomic conditions (e.g. isolated buried teeth or teeth protected in the jawbones) (Aggarwal et al, ; Gupta et al, ). DNA‐based methods for age estimation, such as testing for a specific 4,977 bp deletion of mitochondrial DNA (mtDNA) or for shortening of telomeres, are usually not suitable for analysis of samples with long death‐to‐sampling postmortem intervals as they have very limited accuracy (Meissner and Ritz‐Timme, ).…”

mentioning

confidence: 99%

Inferring chronological age from DNA methylation patterns of human teeth

Giuliani

Cilli

Bacalini

et al. 2015