13
Incremental lines of dental cementum in biological age estimation R. JANKAUSKAS, S. BARAKAUSKAS, R. BOJARUN Department of Anatomy, Histology and Anthropology, Faculty of Medicine, Vilnius University, ˇ Ciurlionio 21, Vilnius LT 2009, Lithuania Summary The aim of this study is to evaluate the use of counting incremental lines of dental root cementum for biological age determination, and to compare it with alternative methods. Two samples were taken: 51 teeth from 49 individuals of known age obtained at the Stomatological Clinic, Vilnius University, as well as the canine teeth from the remains of 48 individuals from the mass graves of Tuskul˙ enai in Vil- nius (inhumed 1944–47). In the latter sample, the chronological age of 43 individuals was known through personal identification. Undecalcified teeth were sectioned with the Leica SP 1600 microtome diamond saw, and incremental line count as a blind test was made on sections of 35 to 100 μm thick- ness. Incremental line count was possible in 82–86 percent of cases. The results of three independent counts showed that intra-observer bias has no significant impact. Biological age was estimated by adding incremental line number to the average age of tooth eruption. It was found that mean absolute error was 6.46 years for the 1 st sample, 6.27 years for the 2 nd sample, and in some cases exceeded 10 years. For the 2 nd sample, the results were compared to those of other methods such as endocranial suture ossification, pubic symphysis morphology and the «combined» method of Nemeskéri. All four methods yield a similar correlation in regard to an individual’s chronological age. The highest correla- tion was found for the combined method, and the lowest one for pubic symphysis morphology. All cor- relations had a similar standard error. Thus our assessment is less enthusiastic than in some past stud- ies; it is suggested that the incremental lines rather have a similar use as other methods. Introduction Accurate determinations of the biological age of an individual remains a problem in physical anthropology. In bioarchaeology, the age of an individual is the basis for further analysis of the demographic and adaptive characteristics of skeletal populations (ACSÁDI & NEMESKÉRI 1970; UBELAKER 1989). In forensic sciences, a precise age determination is a necessary requirement for individual identification (GARMUS 1996). An entire set of age determination methods has been elaborated – both macroscopic (for summary, see SZILVÁSSY 1988) and microscopic (UYTTER- SCHAUT 1985). However, both anthropologists and forensic experts judge these methods to be far from perfect (see RÖSING & KVAAL 1998). The search for new methods thus continues. HOMO HOMO Vol. 52/1, pp. 59–71 © 2001 Urban & Fischer Verlag http://www.urbanfischer.de/journals/homo 0018-442X/01/52/01–59/$ 15.00/0

Incremental lines of dental cementum in biological age estimation

Embed Size (px)

Citation preview

Page 1: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementumin biological age estimation

R. JANKAUSKAS, S. BARAKAUSKAS, R. BOJARUN

Department of Anatomy, Histology and Anthropology, Faculty of Medicine, Vilnius University,Ciurlionio 21, Vilnius LT 2009, Lithuania

Summary

The aim of this study is to evaluate the use of counting incremental lines of dental root cementum forbiological age determination, and to compare it with alternative methods. Two samples were taken: 51teeth from 49 individuals of known age obtained at the Stomatological Clinic, Vilnius University, aswell as the canine teeth from the remains of 48 individuals from the mass graves of Tuskul ˙enai in Vil-nius (inhumed 1944–47). In the latter sample, the chronological age of 43 individuals was knownthrough personal identification. Undecalcified teeth were sectioned with the Leica SP 1600 microtomediamond saw, and incremental line count as a blind test was made on sections of 35 to 100 µm thick-ness. Incremental line count was possible in 82–86 percent of cases. The results of three independentcounts showed that intra-observer bias has no significant impact. Biological age was estimated byadding incremental line number to the average age of tooth eruption. It was found that mean absoluteerror was 6.46 years for the 1st sample, 6.27 years for the 2nd sample, and in some cases exceeded 10years. For the 2nd sample, the results were compared to those of other methods such as endocranialsuture ossification, pubic symphysis morphology and the «combined» method of Nemeskéri. All fourmethods yield a similar correlation in regard to an individual’s chronological age. The highest correla-tion was found for the combined method, and the lowest one for pubic symphysis morphology. All cor-relations had a similar standard error. Thus our assessment is less enthusiastic than in some past stud-ies; it is suggested that the incremental lines rather have a similar use as other methods.

Introduction

Accurate determinations of the biological age of an individual remains a problemin physical anthropology. In bioarchaeology, the age of an individual is the basisfor further analysis of the demographic and adaptive characteristics of skeletalpopulations (ACSÁDI & NEMESKÉRI 1970; UBELAKER 1989). In forensic sciences, aprecise age determination is a necessary requirement for individual identification(GARMUS 1996). An entire set of age determination methods has been elaborated –both macroscopic (for summary, see SZILVÁSSY 1988) and microscopic (UYTTER-SCHAUT 1985). However, both anthropologists and forensic experts judge thesemethods to be far from perfect (see RÖSING & KVAAL 1998). The search for newmethods thus continues.

HOMOHOMO Vol. 52/1, pp. 59–71© 2001 Urban & Fischer Verlaghttp://www.urbanfischer.de/journals/homo

0018-442X/01/52/01–59/$ 15.00/0

Page 2: Incremental lines of dental cementum in biological age estimation

60 R. Jankauskas et al.

Dentition is the most durable and often a very informative system for vertebrateorganisms, and many age determination methods are based on teeth. The colourand fluorescence, although correlated with age, are of limited use in bioarchaeol-ogy as teeth are prone to discoloration due to soil conditions (RÖSING & KVAAL

1998). Attrition of the masticatory surface, often used in bioarchaeology, dependson dietary patterns (MILES 1978; UBELAKER 1989), and, unless the calibration for aparticular population is performed (MAYS 1998), provides only approximateresults. Use of other traits such as periodontal resorption or thickening of thecement of the root (LAMENDIN et al. 1992) also may result in large errors. DentalX-rays are technically complicated, and the standard error is substantial (KVAAL &SOLHEIM 1994). The root cement thickening only moderately correlates with ageand depends on an individual’s sex (SOLHEIM 1990), as well as periodontal disease(see HÜRZELLER & ZANDER 1959, but disputed by GROSSKOPF et al. 1996). Sincethe 1950s, undecalcified thin sections of teeth have been used (GUSTAFSON 1950,1966; LAMPE & RÖTZSCHER 1994) for the evaluation of six traits on longitudinalsections – crown attrition, secondary dentine, periodontal change, dental rootcement apposition, resorption of the root, and root translucency. According toKILIAN (1975), this method has a low error of only 3.6–1.8 years, although otherspecialists are more sceptical (MAPLES & RICE 1979; LUCY & POLLARD 1995). Sev-eral attempts have been made to improve and/or to modify Gustafson’s method(MAPLES 1978; KASHYAP & KOTESWARA RAO 1990; XU et al. 1991; LUCY et al.1996; for others see RÖSING & KVAAL 1998).

Layer structures in teeth have been known for many years (Malpighi noted lay-ers in cementum in the 17th c., Retzius and Owen in dentine in the 19th c.) andstudied in various mammals (e.g., SCHEFFER 1950; SERGEANT & PIMLOTT 1959;RAUSCH 1961; SAXON & HIGHAM 1968; STOTT et al. 1981, ZVJAGIN & STANCHEV

1986). Sometimes these three-dimensional, cone-like layers are called «rings»,because in cross-section they do appear as concentric annulations. Although theprecise mechanism of their appearance is still disputed, it is thought that they arerelated to ontogenetic growth, thus the term «incremental lines» is frequentlyused. As layers of secondary dentine are deposited in the dental pulp cavity, theprocess is restricted by the limited space, which later complicates the attempt tocount the lines. Thus, dental root cementum seems more attractive, as layers aredeposited on the external surface, and there are no restrictions for the incrementalline number increase. Annual deposition lines are composed from a wide and light«summer» layer rich in cementocytes, and a narrow and darker «winter» layer,constituted almost exclusively of calcium salts. Investigations on animals revealedthat the regularities of deposition are influenced by the environment (climaticchanges, quantity and quality of food), as well as metabolic fluctuations includingreproduction cycle and feeding habits (GRUE & JENSEN 1979; STALLIBRASS 1982;GORDON 1993). Thus, the annulations are extremely pronounced for animals withmarked seasonal differences in activity and feeding (KLEVEZAL 1970; STOTT et al.1981). The method was employed for age estimation of various wild mammals(SERGEANT & PIMLOTT 1959; MCEWAN 1963; WADA et al. 1975; KLEVEZAL &KLEINEBERG 1976; MORRIS 1978). In such age determinations, annual rings arecounted and average tooth eruption ages added (ZUHRT et al. 1978); the additionof the age attained at a specific root length (RÖSING & KVAAL 1998) might be more

Page 3: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 61

precise but has not been tested so far. In human age estimation both demineralisedand mineralised, stained and unstained teeth sections can be used. A majority ofresearchers found a high correlation between the number of incremental lines andchronological age (STOTT et al. 1981; CONDON et al. 1986; KVAAL & SOLHEIM

1995). Undecalcified ground sections of teeth are recommended (NAYLOR et al.1985), especially when the quantity of organic components is diminished due tovarious factors such as cremation and soil conditions (GROSSKOPF 1989, 1990).Some studies, however, have failed to find relations between the number of cemen-tal annulations and the age of the individual and consider the use of the methodimpossible (MILLER et al. 1988).

The purpose of this paper is to count incremental lines of dental root cementumin two samples of teeth of individuals of known and of diagnosed chronologicalage and to compare the results with other methods of biological age determina-tion.

Materials and methods

Two samples were chosen for analysis:Sample 1. 51 teeth of 49 individuals that were extracted at the Stomatological

Clinic, Vilnius University (table 1). The patients’ ages were known but the reasonsfor extraction were not known for all cases.

Table 1: Incremental line counts in the sample of clinically extracted teeth (Sample 1).

Refer. Age Tooth Line Line Line Average** Age according Difference fromCase (years) (FDI count – count – count – average line chronologicalNo. No.) 1* 2* 3* count age

1 56 43 41 48 57 51.00 61.30 +5.302 33 42 24 30 26 26.67 34.07 +1.073 54 13 30 27 26 27.67 38.97 –15.034 20 15 8 7 7 7.33 18.43 –1.575 26 18 6 4 8 6.00 23.00 –3.006 36 28 9 12 8 9.67 26.67 –9.337 39 18 15 14 13 14.00 31.00 –8.008 24 18 17 24 15 18.67 35.67 +11.679 24 38 7 11 10 9.33 26.33 +2.33

10 36 48 12 14 12 12.67 29.67 –6.3311 41 38 15 18 20 17.67 34.67 –6.3312 30 41 22 16 20 19.33 25.83 –4.1713 16 32 12 14 13 13.00 20.40 +4.4014 65 26 54 62 60 58.67 65.17 +0.1715 53 17 50 45 52 49.00 61.60 +8.6016 27 46 24 18 23 21.67 28.07 +1.0717 26 47 Count failure18 29 48 Count failure

Page 4: Incremental lines of dental cementum in biological age estimation

62 R. Jankauskas et al.

Sample 2. Canine teeth of 48 individuals from the Stalin era mass grave ofTuskul ˙enai in Vilnius. The calendar age of 43 of these individuals had been previ-ously established after personal identification. The canines were preferred as therewas no postmortal loss during exhumation and no antemortal stomatologicalinterventions. In this sample, biological age was determined in the majority of indi-viduals by means of endocranial suture ossification (ZVJAGIN 1982), morphologyof the pubic symphysis (GARMUS 1996) and a «combined» method (ACSÁDI &NEMESKÉRI 1970, SJØVOLD 1975) (table 2).

Table 1: (Continued).

Refer. Age Tooth Line Line Line Average** Age according Difference fromCase (years) (FDI count – count – count – average line chronologicalNo. No.) 1* 2* 3* count age

19 66 48 Count failure20 12 24 7 9 10 8.67 19.77 +7.7721 31 36 21 25 26 24.00 30.40 –0.6022 30 38 24 16 26 22.00 39.00 +9.0023 48 14 39 38 42 39.67 49.97 +1.9724 12 24 8 4 7 6.33 16.63 +4.6325 17 36 10 14 9 11.00 17.40 +0.4026 46 38 Count failure27 23 36 21 17 23 20.33 26.73 +3.7328 72 31 51 52 43 48.67 55.17 –16.8329 61 21 70 76 58 66.75 74.05 +13.0530 57 47 38 37 39 38.00 50.10 –6.9031 51 17 32 36 38 35.33 47.93 –3.0732 41 25 58 52 42 50.67 61.77 +20.7733 69 48 Count failure34 68 46 81 87 82 83.33 89.73 +21.7335 17 35 9 10 12 10.33 21.73 +4.7336 17 41 8 7 8 7.67 14.17 –2.8337 35 47 23 28 27 26.00 38.10 +3.1038 35 28 34 35 35 34.67 51.67 +16.6739 38 48 22 21 20 21.00 38.00 0.0040 63 47 Count failure41 23 23 15 13 13 13.67 24.97 +1.9742 30 18 Count failure43 45 46 36 40 41 39.00 45.40 +0.4044 54 12 39 31 36 35.33 43.63 –10.3745 52 44 44 46 41 43.67 54.07 +2.0746 32 38 Count failure47 62 37 52 49 55 52.00 64.10 +2.1048 30 48 26 24 23 24.33 41.33 +11.3349 44 37 42 43 44 43.00 55.10 +11.1050 50 23 44 43 40 42.33 53.63 +3.6351 45 43 45 44 41 43.33 53.63 +8.63

Total (N): 42 42 42 42 42 42Average difference (and standard deviation) from chronological age 6.46 (5.63)Maximal difference from chronological age 21.73

* – results of the first, second and third blind count**– average from three counts

Page 5: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 63

Table 2: Age determination on individuals from the Tuskul ˙enai mass graves in Vilnius (four methods)(Sample 2).

Forensic Age by Age Age Age according the incremental Chrono-case No. endocranial according according lines of cementum logical

suture pubic «combined» ageclosing symphysis method Tooth Incremental Age(deviation (deviation (deviation FDI line count (deviationfrom from from No. fromcalendar calendar calendar calendarage) age) age) age)

44 26.10 29.41 30.50 23 16 29.00 27.00(–1.10) (+2.41) (+3.50) (+2.00)

56 22.68 29.63 34.00 23 23 36.00 20.00(+22.68) (+9.63) (+14.00) (+16.00)

80 35.61 – 37.00 13, 23 22 35.00 30.00(+5.61) (+7.00) (+5.00)

86 31.70 – 33.00 13 17 30.00 41.00(–9.30) (–7.00) (–11.00)

161 22.68 – 23.00 13 8 21.00 23.00(–0.32) (0.00) (–2.00)

204 38.45 – 33.00 23 16 29.00 42.00(–3.55) (–9.00) (–13.00)

214 23.39 30.12 31.00 13 14 27.00 27.00(–3.61) (+3.12) (+4.00) (0.00)

337 44.32 47.10 53.75 23 36 49.00 57.00(–12.68) (–9.90) (–3.25) (–8.00)

481 40.60 – 34.00 23 23 36.00 38.00(+2.60) (–4.00) (–2.00)

484 22.70 – 27.50 13 13 26.00 28.00(–5.30) (–.050) (–2.00)

488 – 24.50 27.50 13 10 23.00 22.00(+2.50) (+5.50) (+1.00)

491 43.40 47.10 51.75 13, 23 22 35.00 52.00(–8.60) (–4.90) (–0.25) (–17.00)

492 44.00 39.39 32.00 23 18 31.00 31.00(+13.00 (+8.39) (+1.00) (0.00)

493 35.43 47.10 47.75 23 21 34.00 34.00(+1.43) (+13.10) (+13.75) (0.00)

495 39.87 47.10 47.57 23 16 29.00 31.00(+8.87) (+16.10) (+16.57) (–2.00)

507 45.50 49.00 55.75 43 31 44.00 63.00(–17.50) (–14.00) (–7.25) (–19.00)

510 37.80 – 34.00 23 22 35.00 24.00(+13.80) (+10.00) (+11.00)

511 44.70 44.42 44.25 33 35 48.00 59.00(–14.30) (–14.58) (–14.75) (–11.00)

514 48.94 38.61 43.25 23, 33 28 41.00 36.00(+12.94) (+2.61) (+7.25) (+5.00)

515 45.40 – 51.75 33 28 41.00 43.00(+2.40) (+8.75) (–2.00)

518 34.20 – 31.00 43 10 23.00 25.00(+9.20) (+6.00) (–2.00)

Page 6: Incremental lines of dental cementum in biological age estimation

64 R. Jankauskas et al.

Table 2: (Continued).

Forensic Age by Age Age Age according the incremental Chrono-case No. endocranial according according lines of cementum logical

suture pubic «combined» ageclosing symphysis method Tooth Incremental Age(deviation (deviation (deviation FDI line count (deviationfrom from from No. fromcalendar calendar calendar calendarage) age) age) age)

520 24.58 57.52 52.75 23 – – 31.00(–6.42) (+26.52) (+21.75)

538 33.30 – 34.00 15 23 36.00 34.00(–0.70) (0.00) (+2.00)

543 22.68 28.22 26.50 13, 23 15 28.00 26.00(–3.32) (+2.22) (+0.50) (+2.00)

552 31.19 47.10 41.50 23 – – 37.00(–5.81) (+10.10) (+4.50)

553 39.60 – 34.00 33 – – 28.00(+11.60) (+6.00)

554 – – 34.00 23 20 33.00 26.00(+8.00) (+7.00)

559 22.70 19.89 27.50 33 19 32.00 20.00(+2.70) (–0.11) (+7.50) (+12.00)

560 41.07 – 47.25 23 23 36.00 48.00(–6.93) (–0.25) (–12.00)

561 42.60 – 50.00 23 38 51.00 50.00(–7.40) (0.00) (+1.00)

563 22.70 – 23.00 33 10 23.00 19.00(+3.70) (+4.00) (+4.00)

564 28.90 – 23.00 23 16 29.00 22.00(+6.90) (+1.00) (+7.00)

566 – – 27.50 23 8 21.00 19.00(+8.50) (+2.00)

568 22.70 – 26.00 33 25 38.00 23.00(–0.30) (+3.00) (+15.00)

569 42.80 – 50.00 13 – – 40.00(+2.80) (+10.00)

572 45.30 – 61.00 23 27 40.00 56.00(–10.70) (+5.00) (–16.00)

573 28.30 – 23.00 23 20 33.00 23.00(+5.30) (0.00) (+10.00)

574 22.70 – 30.50 23 21 34.00 27.00(–4.30) (+3.50) (+7.00)

576 26.10 – 30.50 23 13 26.00 26.00(+0.10) (+4.50) (0.00)

577 22.68 19.89 27.50 23 12 25.00 22.00(+0.68) (–2.11) (+5.50) (+3.00)

579 44.32 – 63.00 13 – – 62.00(–17.68) (+1.00)

580 28.50 – 30.50 13 14 27.00 26.00(+2.50) (+4.50) (+1.00)

666 39.50 – 31.00 23 – – 35.00(+4.50) (–4.00)

353 44.80 40.00 38.50 13 29 42.00 –

Page 7: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 65

Before sectioning, the teeth were embedded in special forms in polymere MedimK-Plast™ and left for hardening in room temperature for 2–3 days. The blockswere fixed in the support of the microtome. Undecalcified teeth were sectionedwith the Leica SP 1600 microtome diamond saw. Three to four transverse cutswere made of each tooth root at the mid-upper region. Prior data (ZVJAGIN &STANCHEV 1986) and our own experience indicated that the use of 3–4 sectionswas sufficient – independent incremental line counts on different sections of thesame tooth were highly correlated. Thickness of sections were 35 to 100 µm. Eachsection was washed under a weak stream of tap water, dried on filter paper for15–20 minutes and mounted on pre-marked objective glass with the glue E®. Sec-tions were covered with mounting glass and left for final fixation for 8–12 hours.Using a light microscope on each section where the lines were best distinguishable,the direct count of incremental lines was performed as a blind test, three times foreach section at one day intervals. Results of all three calculations are presented intable 1, while table 2 shows the average number. Dentine/cementum junction linewas not taken into account. Biological age was determined summing up the aver-age number of incremental lines and the average age of tooth eruption (ZUHRT etal. 1978; STALLIBRASS 1982; GROSSKOPF 1990). Regretfully, the method of so-called«gliding correction» (adding the developmental age of exact section position)(RÖSING & KVAAL 1998) appeared to be hardly applicable, as the exact location(distance from enamel-cementum junction) of each section was not fixed.

Table 2: (Continued).

Forensic Age by Age Age Age according the incremental Chrono-case No. endocranial according according lines of cementum logical

suture pubic «combined» ageclosing symphysis method Tooth Incremental Age(deviation (deviation (deviation FDI line count (deviationfrom from from No. fromcalendar calendar calendar calendarage) age) age) age)

360 34.89 47.10 47.75 13 20 33.00 –423 47.20 51.00 49.00 23 – – –485 40.17 47.10 51.25 13 30 43.00 –706 52.43 47.60 49.25 23 37 50.00

–Total (N): 45 22 48 52 41 41 43

Absolute difference from chronological age (years):

Average 6.32 8.37 5.90 – – 6.27 0.00Maximal 17.68 26.52 21.75 – – 19.00 0.00

Page 8: Incremental lines of dental cementum in biological age estimation

66 R. Jankauskas et al.

Results and discussion

Results of Sample 1 analysis

An incremental line count was possible in 42 teeth, or 82.3% of the sample (seetable 1), which is less than CONDON et al. (1986) found in their study. The averagedifference from the chronological (calendar) age, the mean absolute error was 6.46years, and in some cases exceeded 10 years. The results of three independentcounts are highly correlated (r > 0.95; table 3). This means that intra-observer biashas no significant impact on the results. Most other studies also note that intra-observer error is minimal. The incremental line number is highly correlated to

Table 3: Pearson’s correlation coefficients between chronological age, incremental lines and estimatedage (complete Sample 1). Confidence of all coefficients p < 0.01.

Chronological Line count Line count Line count Averageage – 1 – 2 – 3

Line count – 1 0.854Line count – 2 0.852 0.976Line count – 3 0.861 0.963 0.963Average 0.866 0.989 0.990 0.988Estimated age 0.879 0.966 0.966 0.965 0.977

Figure 1: Scatterplot of chronological age versus estimated age (complete sample 1)

Page 9: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 67

chronological age. The correlation between chronological and estimated age is alsohigh (r = 0.879). The scatterplot of estimated versus chronological age revealed asignificant dispersion without detectable regularities of under- or overestimation,increasing slightly with increasing calendar age (figure 1). The most significant lin-ear regression model (with F = 105.915, at 41 degrees of freedom) was:

Y = 0.770 x + 6.686,

where Y = chronological age, x = estimated age, and the standard error of esti-mates is 8.633 years.

As 11 teeth in this sample were third molars (18, 28, 38, 48 according to FDI),whose eruption age varies significantly, we made an attempt to recalculate thedata. Table 4 shows that the results were only slightly better. The average differ-ence from the chronological age was 6.05 years (standard deviation 5.91 years). Insome cases, the difference from chronological age again exceeded 10 years. Thelinear regression model (F = 94.692, at 30 degrees of freedom) in this case is:

Y = 0.801 x + 5.501.

Exclusion of third molars in this regression, however, leads to an even highererror of estimate (8.995 years). Exclusion of the third molars therefore onlyslightly improves the result.

Results of Sample 2 analysis

Canine teeth were the focus of this sample. An incremental line count was made in37 cases, or 86.0% (table 2). Average difference from the chronological age was6.27 (standard deviation 5.69) years, so it does not differ substantially from othermethods. In some cases, the difference from actual age exceeds 10 years, and themaximal difference was 19 years. The scatterplot of incremental line number versuschronological age also revealed significant dispersal of data around the linear regres-sion line (figure 2). The linear regression (F = 41.756 at 36 degrees of freedom):

Y = 1.214 x + 8.656

gives a standard error of estimate of 8.612 years. This does not differ from resultsobtained during the Sample 1 analysis, which included teeth with different erup-tion ages.

Table 4: Pearson’s correlation coefficients between chronological age, incremental lines and estimatedage (Sample 1, third molars excluded). Confidence of all coefficients p < 0.01.

Chronological Line count Line count Line count Averageage – 1 – 2 – 3

Line count – 1 0.891Line count – 2 0.882 0.978Line count – 3 0.900 0.956 0.965Average 0.902 0.987 0.991 0.987Estimated age 0.905 0.980 0.979 0.982 0.992

Page 10: Incremental lines of dental cementum in biological age estimation

68 R. Jankauskas et al.

In an attempt to compare all four age estimation methods, we performed a Pear-son correlation analysis (table 5). All four methods show a reliable correlationwith the individual’s chronological age. The highest correlation was represented bythe «combined» method, and the lowest correlation with the pubic symphysismorphology.

Figure 2: Scatterplot of incremental lines versus chronological age (sample 2)

Table 5: Pearson’s correlation coefficients between age estimations in the Tuskule·nai mass grave sam-ple.

Chronological age Biological age by incremental lines

Biological age according 0.773 0.741endocranial suture closure (p <0.01) (p <0.01)Biological age according 0.671 0.732pubic symphysis (p <0.01) (p <0.01)Biological age according 0.840 0.738«combined» method (p <0.01) (p < 0.01)Biological age according 0.765 1.000incremental lines (p <0.01)

Page 11: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 69

Conclusions

This study revealed both positive and negative aspects of the incremental linecount method. First, incremental line count is possible in about 80–85 percent ofexamined cases (a frequency that is lower than in previous studies). A probablefactor is pathological changes of the cementum (i.e. massive and numerous cemen-tocytes obscuring the lines). Such a large number of count failures could also berelated to the simple technique employed, which was a direct count using lightmicroscopy. One might expect that the use of more sophisticated techniques, e.g.,phase contrast with digital image analysis, could improve the results. The experi-ence of other analysts (BUBA 2000; KAGERER & GRUPE 2000) points to substantialdifficulties in the application of the method in case of pathological periodontalprocesses. However, minor pathologies do not affect results substantially, asshown by our analysis of both samples. It was found that the correlation tochronological age and average errors of biological age estimation are similar to theerrors established by the majority of other studies (see RÖSING & KVAAL 1998 fordiscussion) and the errors of other methods. Only GROSSKOPF (1990) and KAGERER

& GRUPE (2000) obtained substantially lower errors. Differences in opinion aboutthe reliability of the method reflect the use of different techniques (undecalcified ordecalcified sections; stained or unstained slices; longitudinal or transverse sections;simple light or phase contrast microscopy). One might speculate that seasonal fluc-tuation in metabolism rate for humans born in the 20th c. is less pronounced thanthat of archaeological populations, and therefore the incremental lines of dentalcementum do not demonstrate expected simple regularity. As RÖSING & KVAAL

(1998) have mentioned, there are possibilities that some humans appose more thanone layer every year, and in older individuals some layers could be skipped. Thehypothesis that a larger sample and calculation of multiple regression equationsfor each tooth (ZVJAGIN & STANCHEV 1986) could increase the reliability of themethod still needs verification. We conclude that the incremental line countmethod can be used as an independent verification of conventional methods, and,in the case of very fragmentary skeletons, it is the method of choice.

Acknowledgements

We thank PD Dr. Ursula Wittwer-Backofen, Justus-Liebig-Universität Gießen, for practical training andadvice. We are also grateful to the reviewers Prof. Dr. G. Grupe and PD Dr. I. Schröder, for their thor-ough analysis of the manuscript and useful suggestions. Credits should be given also to RaymondSidrys for the editing of the English version of the paper. This research was supported by grants fromDAAD and Lithuanian State Science Foundation (grant no. 344/98).

References

ACSÁDI G, NEMESKÉRI J (1970) History of Human Life Span and Mortality. Akadémiai Kiado, Budapest.BUBA H (2000) Berücksichtigung der Parodontose bei der Methode der Zahnzementannulation. Homo

51/Suppl.: 13.CONDON K, CHARLES DK, CHEVERUD JM, BUIKSTRA JE (1986) Cementum annulation and age determi-

nation in Homo sapiens II. Estimates of accuracy. Am J Phys Anthrop 71: 321–330.

Page 12: Incremental lines of dental cementum in biological age estimation

70 R. Jankauskas et al.

GARMUS A (1996) Lithuanian Forensic Osteology. Baltic Medico-Legal Association, Vilnius.GORDON BC (1993) Archaeological tooth and bone seasonal increments: the need for standardised

terms and techniques. Archaeozoologia V/2: 9–16.GROSSKOPF B (1989) Incremental lines in prehistoric cremated teeth. A technical note. Z Morph

Anthrop 77: 309–311.GROSSKOPF B (1990) Individualaltersbestimmung mit Hilfe von Zuwachsringen im Zement bodenge-

lagerter menschlicher Zähne. Z Rechtsmed 103: 351–359.GROSSKOPF B, DEUDEN JM, KRÜGER W (1996) Untersuchung zur Zementapposition bei Parodontitis

marginalis profunda. Dt Zahnärztl Z 51: 295–297.GRUE H, JENSEN B (1979) Review of the formation of incremental lines in tooth cementum of terrestrial

mammals. Danish Review of Game Biology 117: 2–49.GUSTAFSON G (1950) Age determination on teeth. J Am Dent Ass 41: 45–54.GUSTAFSON G (1966) Forensic Odontology. Staples Press, London.HÜRZELER B, ZANDER HA (1959) Cementum apposition in periodontally diseased teeth. Helv. Odont

Acta 3: 1–3.KAGERER P, GRUPE G (2000) Zahnzementzuwachsringe: Dechiffrierbare Annalen in der Paläopathologie,

Paläodemographie und Rechtsmedizin. Homo 51/Suppl.: 62.KASHYAP VK, KOTESWARA RAO NR (1990) A modified Gustafson method of age estimation from teeth.

Forensic Sci Int 47: 237–247.KILIAN J (1975) Age determination on teeth by means of Gustafson’s method. Scripta Medica (Brno) 48:

197–201.KLEVEZAL GA (1970) A retrospective evaluation of the individual features of mammal growth based on

the structure of dentine and bone layers. Ontogenez 1: 362–372.KLEVEZAL GA, KLEINEBERG SE (1976) Opredelenije vozrasta mlekopitajuscich po sloistym strukturam

zubov i kosti. Nauka, Moskva.KVAAL S, SOLHEIM T (1994) A non-destructive dental method for age estimation. J For Odonto-Stomatol

12: 6–11.KVAAL S, SOLHEIM T (1995) Incremental lines in human cementum in relation to age. Europ J Oral Sci

103: 225–230.LAMENDIN H, BACCINO E, HUMBERT JF, TAVERNIER JC, NOSSINTCHOUK RM, ZERILLI A (1992) A simple

technique for age estimation in adult corpses: the two criteria dental method. J Forensic Sci 37:1373–1379.

LAMPE H, RÖTZSCHER K (1994) Forensic odontology: age determination from adult human teeth. MedLaw 13: 623–628.

LUCY D, AYKROYD RG, POLLARD AM, SOLHEIM T (1996) A Bayesian approach to adult human age esti-mation from dental observations by Johanson’s age changes. J For Sci 41: 189–194.

LUCY D, POLLARD AM (1995) Further comments on the estimation of error associated with theGustafson dental age estimation method. J For Sci 40: 222–227.

MAYS S (1998) The archaeology of human bones. Routledge, London and New York.MAPLES WR (1978) An improved technique using dental histology for estimation of adult age. J For Sci

23: 764–770.MAPLES WR, RICE PM (1979) Some difficulties in the Gustafson dental age estimations. J For Sci 24:

168–172.MCEWAN EH (1963) Seasonal annuli in the cementum of the teeth of Barren Ground caribou. Can J

Zool 41: 111–113.MILES AEW (1978) Teeth as an indicator of age in man. In BUTLER PM, JOYSEY KA (eds) Development,

function and evolution of teeth. Academic Press, London, 455–464.MILLER CS, DOVE SB, COTTONE JA (1988) Failure of use of cemental annulations in teeth to determine

the age of humans. J For Sci 33: 137–143.MORRIS P (1978) The use of teeth for estimating the age of wild mammals. In BUTLER PM, JOYSEY KA

(eds) Development, function and evolution of teeth. Academic Press, London, 483–494.NAYLOR JW, MILLER WG, STOKES GN, STOTT GG (1985) Cemental annulation enhancement: a tech-

nique for age determination in man. Am J Phys Anthrop 69: 197–200.RAUSCH RL (1961) Notes on the black bear Ursus americanus pallus, in Alaska, with particular refer-

ence to dentition and growth. Z Säugetierkde 26: 77–107.RÖSING FW, KVAAL SI (1998) Dental age in adults. A review of estimation methods. In ALT KW, RÖSING

FW, TESCHLER-NICOLA M (eds) Dental Anthropology. Fundamentals, Limits, and Prospects. Springer,Wien, 443–468.

Page 13: Incremental lines of dental cementum in biological age estimation

Incremental lines of dental cementum in biological age estimation 71

SAXON A, HIGHAM CFW (1968) Identification and interpretation of growth rings in the secondary den-tal cementum of Ovis aries L. Nature 219: 634–635.

SCHEFFER VB (1950) Growth layers on the teeth of Pinnipedia as an indication of age. Science 112:309–311.

SERGEANT DE, PIMLOTT DH (1959) Age determination in moose from sectioned incisor teeth. J. ofWildlife Management 23: 315–321.

SJØVOLD T (1975) Tables of the combined method for determination of age at death given byNemeskéri, Harsányi and Acsádi. Anthrop Közl 19: 9–22.

SOLHEIM T (1990) Dental cementum apposition as an indicator of age. Scand. J Dent Res 98: 510–519.STALLIBRASS S (1982) The use of cementum layers for absolute ageing of mammalian teeth: a selective

review of the literature with suggestions for further studies and alternative applications. In WILSON

B, GRIGSON C, PAYNE S (eds) Aging and sexing animal bones from archaeological sites. BAR, BS 109,Oxford, 109–126.

STOTT GG, SIS RF, LEVY BM (1981) Cemental annulation as an age criterion in forensic dentistry J DentRes 61: 814–817.

SZILVÁSSY J (1988) Altersdiagnose am Skelett. In KNUSSMAN R (ed) Anthropologie: Handbuch der ver-gleichenden Biologie des Menschen. Gustav Fischer Verlag, Stuttgart, 421–443.

UBELAKER DH (1989) Human Skeletal Remains: Excavation, Analysis, Interpretation. 2nd ed. Tarax-acum, Washington DC.

UYTTERSCHAUT HT (1985) Determination of skeletal age by histological methods. Z Morph Anthrop75: 331–340.

WADA K, OHTAISHI N, HACHIYA N (1975) Determination of age in the Japanese monkey from growthlayers in the dental cementum. Primates 19: 775–784.

XU XH, PHILIPSEN HP, JABLONSKI NG, WEATHERHEAD B, PANG KM, ZHU JZ (1991) Preliminary reporton a new method of human age estimation from single adult teeth. For Sci Int 51: 281–288.

ZUHRT T R, ROTTSTOCK F, WINTERFELD RI (1978) Möglichkeiten und Methoden der Stomatologie beider Identifizierung. In HUNGER H, LEOPOLD D (Hrg) Identifikation. Springer-Verlag, Berlin, p.287–340.

ZVJAGIN VN (1982) Individuelle Altersbestimmung des Menschen an Hand des Schädels unter Anwen-dung von Gleichungen der multiplen Regression. Kriminalistik und forensische Wissenschaften 44:33–44.

ZVJAGIN VN, STANCHEV NA (1986) Diagnostika vozrasta cheloveka po mikrostrukturnym osobennos-tiam tviordykh tkanej zubov. Sudebno-medicinskaja ekspertiza 29: 54–57.

Authors address: Prof Dr RIMANTAS JANKAUSKAS, Department of Anatomy, Histology and Anthropol-ogy, Faculty of Medicine, Vilnius University, Ciurlionio 21, Vilnius LT2009, Lithuania, tel. (+370 2)651764, fax (+370 2) 263167, e-mail: [email protected]

Received 4 Sept 2000, accepted 31 Oct 2000, resubmitted 20 Nov 2000