Variations in pulp/tooth area ratio as an indicator of age: a preliminary study

This paper details a method for age determination of adults from single rooted teeth. The sample consisted of 100 Italian white Caucasian patients (46 men, 54 women) aged between 18 and 72 years. The single rooted maxillary right canine was utilized in this preliminary study. Pulp/root ration, tooth length, pulp/tooth length ratio, pulp/tooth area and pulp/root width ratios at three different levels were computed. Pearson's correlation coefficients between age and these variables showed that the ratio between pulp and tooth area correlated best with age (r2 = 0.85). Stepwise multiple regression models yielded a linear relationship between pulp/root width at mid-root level and chronological age and a linear relationship when pulp/tooth area was compared to age. Statistical analysis indicated that these two variables explain 84.9% of variations in estimated chronological age. The median of the absolute value of residual errors between actual and estimated ages was less than four years.     

Age estimation of adults from dental radiographs

Previous studies have shown that with advancing age the size of the dental pulp cavity is reduced as a result of secondary dentine deposit, so that measurements of this reduction can be used as an indicator of age. The aim of the present study was to find a method which could be used to estimate the chronological age of an adult from measurements of the size of the pulp on full mouth dental radiographs. The material consisted of periapical radiographs from 100 dental patients who had attended the clinics of the Dental Faculty in Oslo. The radiographs of six types of teeth from each jaw were measured: maxillary central and lateral incisors and second premolars, and mandibular lateral incisors, canines and first premolars. To compensate for differences in magnification and angulation on the radiographs, the following ratios were calculated: pulp/root length, pulp/tooth length, tooth/root length and pulp/root width at three different levels. Statistical analyses showed that Pearson's correlation coefficient between age and the different ratios for each type of tooth was significant, except for the ratio between tooth and root length, which was, therefore, excluded from further analysis. Principal component analyses were performed on all ratios, followed by regression analyses with age as dependent variable and the principal components as independent variables. The principal component analyses showed that only the two first of them had significant influence on age, and a good and easily calculated approximation to the first component was found to be the mean of all the ratios. A good approximation to the second principal component was found to be the difference between the mean of two width ratios and the mean of two length ratios, and these approximations of the first and second principal components were chosen as predictors in regression analyses with age as the dependent variable. The coefficient of determination (r²) for the estimation was strongest when the ratios of the six teeth were included (r² = 0.76) and weakest when measurements from the mandibular canines alone were included (r² = 0.56). Measurement on dental radiographs may be a non-invasive technique for estimating the age of adults, both living and dead, in forensic work and in archaeological studies, but the method ought to be tested on an independent sample.     

Age-related changes in pulp cavity of incisors as a determinant for forensic age identification

To find a simple and convenient method for age identification upon age-related pulp cavity narrowing, the mesiodistal diameters of the cervical pulp chamber, the middle and terminal parts of the root canal of the pulp cavity of 620 incisors were measured on radiographs taken in situ in 80 Chinese aged from 15 to 80. It was shown that the three mesiodistal diameters significantly decreased in a negative linear relationship with age (-0.4233 ≤ r ≥ -0.8465) in all incisors, but the narrowing velocity of the cervical pulp chamber and the middle part of the root canal in the maxillary incisors (b = -0.02 mm) was faster than that in the mandibular incisors (b = -0.01 mm). Accordingly, a mathematical model describing the ages as a function of any one of the three mesiodistal diameters of the pulp cavity was deduced, which would be useful for age identification in forensic medicine or archaeology.     

Reliability in age determination by pulp/tooth ratio in upper canines in skeletal remains

Estimation of age of skeletal remains is one of the most complex questions for anthropologists. The most common macroscopic methods are based on dental wear and histological evaluation of bone remodeling. These methods are often qualitative, require great technical expertise, and have proved inexact in the estimation of ages over 50 years. Certain dental methods investigate the apposition of secondary dentine, in the study of tooth cross-sections, and X-rays to study width, height, and pulp area. The primary author previously proposed a method of estimating the age of a living person based on the pulp/tooth ratio (PTR) method in the upper canines. The aim of the present study is to verify whether the PTR method can also be used to estimate the age at death of skeletal remains. This paper investigates the study of historical samples of known age as a means to validate the proposed method.     

Application of Kvaal et al.'s age estimation method to panoramic radiographs from Turkish individuals

Age estimation of living adult individuals can be accomplished with limited methods. Radiographic dental methods based on the pulpal narrowing with secondary dentin formation have been presented. In the present study, Kvaal et al.'s method, one of the radiographic dental age estimation methods, was applied to panoramic radiographs from Turkish individuals. The correlation between chronological and estimated ages was examined and the feasibility of length and width measurements of pulp cavity was evaluated for age estimation. The study population consisted of 123 patients with ages ranging from 14 to 57 years. The measurements of the length and width of six types of teeth on digitized panoramic radiographs were performed, and the ratios between tooth and pulp cavity measurements were calculated. Age was estimated using the linear regression models presented by Kvaal et al. and Paewinsky et al. High differences were observed between chronological and estimated ages. Measurement ratios showed no significant or weak correlation with age. The linear regression models were derived using variables that were significantly correlated with age. The determination coefficients of the models varied from 0.035 to 0.345. In conclusion, a difference of more than 12 years in the chronological and estimated ages derived using regression models in literature was found on panoramic radiographs in Turkish individuals. The length and width of the pulp cavity, measured according to the method of Kvaal et al. using panoramic radiographs, were insufficient to precisely estimate the age of Turkish individuals.     

Pulp volume quantification methods in cone-beam computed tomography for age estimation: A critical review and meta-analysis

The secondary dentin deposition that occurs after the tooth formation process results in a decrease in pulp cavity volume in adolescents and adults. The purpose of this critical review was to correlate pulpal and/or dental volume on cone-beam computed tomography (CBCT) with chronological age approximation. A subobjective was to investigate which methodology and CBCT technical parameters would be most appropriate to evaluate this correlation. This critical review followed the PRISMA guidelines, and it was conducted by a search through PubMed, Embase, SciELO, Scopus, Web of Science, Cochrane Library databases, as well as gray literature. Primary studies that used pulp volume, or pulp chamber to tooth volume ratio measured using CBCT were included. Seven hundred and eight indexed and 31 non-indexed records were identified. A qualitative analysis was performed including 25 selected studies with a total of 5100 individuals, age ranging from 8 to 87 years without sex predilection. The most used method was pulp volume/tooth volume. CBCT voxel size ranged between 0.09 and 0.5. Manual segmentation associated with threshold algorithms was used in most of the studies. Correlation between the pulp volume/tooth volume ratio was moderate: −0.66 for the upper central incisors, −0.59 for upper canines and −0.56 for lower canines. High heterogeneity was observed among the studies. It is concluded that pulp volume should be used with caution in age estimation. Evidence supports the preferable use of upper incisors with pulp volume/tooth volume ratio for age estimation. There is not enough evidence that voxel size interferes in age estimation by pulp volume.     

Age calculation using X-ray microfocus computed tomographical scanning of teeth: a pilot study

To correlate dental age with an individual's chronological age based on the calculated volume ratio of pulp versus tooth volume measured, an X-ray microfocus computed tomography unit (microCT) with 25 microm spatial resolution was used to non-destructively scan 43 extracted single root teeth of 25 individuals with well-known chronological age. Custom-made analysis software was used by two examiners to obtain numerical values for pulpal and tooth volume. The ratio of both was calculated and statistically processed. No significant intra- or inter-examiner differences were found. In fact, a very strong concordance correlation coefficient was found. Linear regression analysis showed a coefficient of determination (r) of 0.31 which suggests that there is a rather weak correlation between the volume ratio of pulp versus tooth and biological age. Although rather time consuming, this technique shows promising results for dental age estimation in a non-destructive manner using X-ray microfocus computed tomography.     

A simple technique for age estimation in adult corpses: the two criteria dental method.

A method for age determination of adults from single rooted teeth is presented. It is based on the measurement of two dental features: periodontosis height times 100/root height (P) and transparency of the root height times 100/root height (T). These measurements are made on the labial surface of the entire tooth without section and do not require special equipment or training. The application of multiple regression analysis to a working sample of 306 teeth of known age, sex and race provided the following equation: Age (years) = 0.18 x P + 0.42 x T + 25.53. The mean error between the actual and estimated age was +/- 10 years on the working sample and +/- 8.4 years on a control sample made of 45 forensic science cases. Upper incisors showed a better precision than the other single rooted teeth and accuracy was not sex related. A comparison of the Gustafson and Lamendin methods on a control sample of 39 teeth resulted in an advantage of the latter considering the mean error on the estimation (14.2 +/- 3.4 years for Gustafson versus 8.9 +/- 2.2 for Lamendin). The Lamendin method can be practical interest for any forensic pathologist or dentist as it is fast, easy to use, and reasonably accurate except for cases of individuals under age 40 where other methods must be preferred.     

Three-dimensional modeling of the various volumes of canines to determine age and sex: a preliminary study

Canines are usually used in anthropological and forensic sciences for sex and age determination. The best methods to estimate age are based on secondary dentine apposition, evaluated from periapical X-rays. The aim of this study was to propose a new method of sex and age estimation using 3D models to obtain more precise predictions using tooth volumes. Fifty-eight dental CT scans of patients aged 14-74 with a well-balanced sex ratio composed the sample. One hundred and thirty-three healthy canines were modeled (Mimics 12.0). The sample was divided into a training sample and a validation sample. An age formula was determined using the "pulp volume/tooth volume" ratio. Sex prediction was adjusted with total volumes. Applying the equations to the validation sample, no significant difference was found between the real and predicted ages, and 100% of the sex predictions were correct. This preliminary study gives interesting results, and this method is worth being tested on a larger data sample.     

Dental age estimation through volume matching of teeth imaged by cone-beam CT

A custom-made voxel counting software for calculating the ratio between pulp canal versus tooth volume based on cone-beam CT tooth images was developed and evaluated. The aim of this study was to attempt establishing a correlation between the chronological age of a certain individual and the pulp/tooth volume ratio of one of the teeth. Twenty-eight single rooted teeth of 19 individuals with well-known chronological age were scanned by the cone-beam CT (3D Accuitomo, J. Morita, Kyoto, Japan). Next the images were analyzed using the custom-made software. Linear regression analysis was performed. The results of the analysis showed a moderate correlation between the pulp/tooth volume ratio and biological age with a coefficient of determination (R2) of 0.29. Although the present work was limited to a pilot study, the developed technique showed promising results for dental age estimation in a non-invasive manner using cone-beam CT images in living individuals.     

Age estimation by pulp/tooth ratio in canines by mesial and vestibular peri-apical X-rays

Changes in the size of the pulp canal, caused by apposition of secondary dentine, are the best morphometric parameters for estimating age by X-rays. The apposition of secondary dentine is the most frequently used method for age estimation in adult subjects. In two previous papers, we studied the application of the pulp/tooth area ratio by peri-apical X-rays as an indicator of age at death. The aim of the present study was to test the accuracy of age evaluation by combined analysis of labio-lingual and mesial peri-apical X-rays of lower and upper canines. A total of 200 such X-rays were assembled from 57 male and 43 female skeletons of Caucasian origin, aged between 20 and 79 years. For each skeleton, dental maturity was evaluated by measuring the pulp/tooth area ratio according to labio-lingual and mesial X-rays on upper (x(1), x(2)) and lower (x(3), x(4)) canines. Very good agreement was found between intra-observer measurements. Statistical analysis showed that all variables x(1), x(2), x(3), and x(4) and the first-order interaction between x(1) and x(3) contributed significantly to the fit, so that they were included in the regression model, yielding the following regression formula: Age = 120.737 - 337.112x(1) - 79.709x(2) - 364.534x(3) - 65.655x(4) + 1531.918x(1)x(3) . The residual standard error of estimated ages was 3.62 years, with 94 degrees of freedom, and the median of the residuals was -0.155 years, with an interquartile range of 4.96 years. The accuracy of the method was ME = 2.8 years, where ME is the mean prediction error. The model also explained 94% of total variance (R(2) = 0.94).     

上、下尖牙髓腔/牙体表面积比值的年龄判定价值研究

目的 通过三维重建测量上、下颌尖牙髓腔/牙体表面积比值(Pulp/Tooth area Ratio,PTR)来推断个体年龄,为临床年龄推断的应用提供科学依据.方法 收集口腔门诊患者年龄在16～65岁200例锥形束CT(Cone beam computed tomography,CBCT)影像资料,以4个尖牙为测量对象并...     

Human dental age estimation by calculation of pulp-tooth volume ratios yielded on clinically acquired cone beam computed tomography images of monoradicular teeth

Abstract: Secondary dentine is responsible for a decrease in the volume of the dental pulp cavity with aging. The aim of this study is to evaluate a human dental age estimation method based on the ratio between the volume of the pulp and the volume of its corresponding tooth, calculated on clinically taken cone beam computed tomography (CBCT) images from monoradicular teeth. On the 3D images of 111 clinically obtained CBCT images (Scanora^®3D dental cone beam unit) of 57 female and 54 male patients ranging in age between 10 and 65 years, the pulp–tooth volume ratio of 64 incisors, 32 canines, and 15 premolars was calculated with Simplant^® Pro software. A linear regression model was fit with age as dependent variable and ratio as predictor, allowing for interactions of specific gender or tooth type. The obtained pulp–tooth volume ratios were the strongest related to age on incisors.     

Postmortem pink teeth.

A series of cases is reported in which pink teeth were observed during the postmortem period. Most cases were associated with decomposition in a moist environment. Experimental procedures led to the extraction of pink material from dentin and demonstration that hemoglobin and serum proteins were present. The pink-tooth phenomenon was duplicated in human teeth by instilling into the pulp chambers whole blood and blood with the red cells hemolyzed. The change was manifested in teeth of dogs after freezing, heating, and decomposition in a moist environment. The authors postulate that pink teeth occur as a result of breakdown of red blood cells in the pulp chamber of the tooth and diffusion of hemoglobin and other serum proteins into the dentin via the dential tubules. Histochemical studies show that the brown or gray material in some teeth subjected to postmortem aging is probably hemoglobin and serum proteins. Factors of age, vascularity of the pulp chamber, and postmortem conditions are discussed in relation to the postmortem development of pink teeth.     

Individual age determination using growth rings in the cementum of buried human teeth

Incremental lines of the dental cementum were used for individual age determination in 102 teeth. 66 of them come from different historic periods, 15 teeth were cremated. 36 modern teeth of known age were use as controls. The incremental lines were investigated by use of 100 microns thin cross-sections of the root. Age determination by this method was possible in every tooth, independent of incinaration of various burial conditions. The individual age was determined by adding the mean value of the repeatedly counted incremental lines to the sex-specific eruption age of the tooth in question. Since average deviation from known age is +/- 3.23 years only, counting the incremental lines represent a very advantageous, quantitative method for individual age determination.     

Age estimation by pulp/tooth ratio in lower premolars by orthopantomography

Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Since 2004, in order to examine patterns of secondary dentine apposition, Cameriere et al. have been extensively studying the pulp/tooth area ratio of the canines by panoramic and peri-apical X-ray images. The main aim of this paper is to examine the relationship between age and age-related changes in the pulp/tooth area ratio in monoradicular teeth, with the exception of canines, by orthopantomography. A total of 606 orthopantomograms of Spanish white Caucasian patients (289 women and 317 men), aged between 18 and 75 years and coming from Bilbao and Granada (Spain), was analysed. Regression analysis of age of monoradicular teeth indicated that the lower premolars were the most closely correlated with age. An ANCOVA did not show significant differences between men and women. Multiple regression analysis, with age as dependent variable and pulp/tooth area ratio as predictor, yielded several formulae. R(2) ranged from 0.69 to 0.75 for a single lower premolar tooth and from 0.79 to 0.86 for multiple lower premolar teeth. Depending on the available number of premolar teeth, the mean of the absolute values of residual standard error, at 95% confidence interval, ranged between 4.34 and 6.02 years, showing that the pulp/tooth area ratio is a useful variable for assessing age with reasonable accuracy.     

根据颅骨特征推断中国东北地区汉族成年男性眼外形

目的研究颅骨影像学指标与眼外形之间的相关性。方法对101例20~40周岁中国东北地区汉族成年男性,拍摄头面部正面相片和正侧位X线片,对面宽(x1)、上面宽(x2)、两眶宽(x3)、全面高(x4)、上面高(x5)、颅骨最大宽(x6)、额骨最小宽(x7)、眶宽Ⅱ(x8)、前眶间宽(x9)、全颅最大高(x10)、鼻骨最小宽(x11)、眶高(x12)进行测量及统计学分析。结果通过线性回归分析,建立的推定眼内眦间距(y1)、眼外眦间距(y2)的回归方程分别为y1=0.025 x2+0.291 x3-0.011 x7+0.041 x10-0.525(R=0.613,SEE=0.222 cm)、y2=1.703-0.08 x2+0.573 x3-0.142 x4+0.421 x5+0.096 x7-0.256 x8+0.149 x9+0.071 x10(R=0.745,SEE=0.341 cm)。经回代检验,两方程在±1SEE的准确率分别为75.2%和80.2%。结论所建立的眼外形的回归方程具有较高的推定精度,可以用于实际颅骨面貌复原工作。     

Precision and reliability of pulp/tooth area ratio (RA) of second molar as indicator of adult age

This paper discusses a method for assessing adult age based on the relationship between age and measurement of the pulp/tooth area ratio (RA) of the second molar teeth. The sample consisted of 312 Italian white Caucasian patients (135 men, 177 women) aged between 14 and 24 years. Orthopantomograph samples (OPGs) were analyzed by the same observer and calibrated by kappa statistics. Probabilities of an individual being older than 18 years of age (adult age) were derived using measurements of the ratio pulp/tooth area (RA) of the second molar teeth and the dichotomized stages of third molar development (Tm) as explanatory variables. These results were exploited to establish a threshold value to assign an individual to juvenile or adult age. A cut-off value of RA* = 0.088 was applied if Tm = 0 and RA* = 0.097 if Tm = 1. The sensitivity of this test was 91% and its specificity 94.5%. The proportion of individuals with correct classifications was 92%.     

Sex determination by discriminant analysis of patella measurements

The authors have analyzed 80 skeletons (40 males and 40 females) from the collection at the Institute of Legal Medicine of the University of Bari belonging to a known contemporary Southern Italian population; time of death was around 1970 and ages ranged from 25 to 80 years. Seven measurements taken on 80 intact, undeformed right patellae (max height, max width, thickness, height and width of the external facies articularis, height and width of the internal facies articularis) were used to determine sex by multivariate discriminant analysis. One function associating two parameters (max width and thickness) obtained the highest value of correct sex determination with a rate of 83.8%; other functions showed a higher percentage of misclassification (up to 17.5%). This study tests the success rate of correct sex prediction based exclusively on patellar dimensions. The discriminant functions carried out by statistical analysis may aid the forensic anthropologist when no other human skeletal remains suitable for sex determination are available.     

Application of Lamendin's adult dental aging technique to a diverse skeletal sample

Lamendin et al. (1) proposed a technique to estimate age at death for adults by analyzing single-rooted teeth. They expressed age as a function of two factors: translucency of the tooth root and periodontosis (gingival regression). In their study, they analyzed 306 singled rooted teeth that were extracted at autopsy from 208 individuals of known age at death, all of whom were considered as having a French ancestry. Their sample consisted of 135 males, 73 females, 198 whites, and 10 blacks. The sample ranged in age from 22 to 90 years of age. By using a simple formulae (A = 0.18 x P + 0.42 x T + 25.53, where A = Age in years, P = Periodontosis height x 100/root height, and T = Transparency height x 100/root height), Lamendin et al. were able to estimate age at death with a mean error of +/- 10 years on their working sample and +/- 8.4 years on a forensic control sample. Lamendin found this technique to work well with a French population, but did not test it outside of that sample area. This study tests the accuracy of this adult aging technique on a more diverse skeletal population, the Terry Collection housed at the Smithsonian's National Museum of Natural History. Our sample consists of 400 teeth from 94 black females, 72 white females, 98 black males, and 95 white males, ranging from 25 to 99 years. Lamendin's technique was applied to this sample to test its applicability to a population not of French origin. Providing results from a diverse skeletal population will aid in establishing the validity of this method to be used in forensic cases, its ideal purpose. Our results suggest that Lamendin's method estimates age fairly accurately outside of the French sample yielding a mean error of 8.2 years, standard deviation 6.9 years, and standard error of the mean 0.34 years. In addition, when ancestry and sex are accounted for, the mean errors are reduced for each group (black females, white females, black males, and white males). Lamendin et al. reported an inter-observer error of 9+/-1.8 and 10+/-2 sears from two independent observers. Forty teeth were randomly remeasured from the Terry Collection in order to assess an intra-observer error. From this retest, an intra-observer error of 6.5 years was detected.