Thermal Modifications of Root Transparency and Implications for Aging: A Pilot Study

Root transparency has proven to be related to age and has been considered by different odontological methods for age estimation. Very little is known concerning possible variations of root transparency with heat, although the applicability of the method to burnt remains depends on the possible modifications of this specific variable. This pilot study presents the results of an experiment performed on 105 teeth obtained from dental patients and autopsy material, heated in an industrial oven at 50°C, 100°C, 150°C and 200°C. Root transparency was measured before and after the charring experiment. The heating process proved to radically modify root transparency, which decreased in 20% of samples at 50°C, in 34.6% at 100°C, in 50% at 150°C, in 77% at 200°C. The overall correlation index (CI) between decrease in root transparency and increase in temperature amounted to 0.96. These results show that heat may modify root transparency and suggest caution in using methods based on root transparency for age estimation.     

Age estimation methods using anthropological parameters on human teeth-(A0736)

The research was conducted on the 160 intact extracted human teeth with one and two roots of the known age and sex. The teeth were disinfected, dried and X-rayed. After that the section of the longitudinal cut through the teeth was performed in order to facilitate monitoring of all tissues and morphological characteristics of the teeth. The age was determined in three ways: Method 1 [G.Bang, E. Ramm, Determination of age in humans from root dentin transparency, Acta Odontol. Scand. 28 (1970) 3-35]--analysis of the translucency of the root dentine, Method 2 [S. Kvaal, T. Solheim, A non-destructive dental method for age estimation, J. Forensic Odonto-stomatol. 12 (1994) 6-11]--analysis of the root and the root canal from the X-ray, Method 3 [G. Johanson, Age determination from human teeth, Odontol. Revy. 22 (1971) 1-126]--analysis of six parameters on each teeth. All data were subject to the correlation and regression analysis which showed the following: all of the three applied methods were in the significant correlation with the real age, and the best of them proved to be Method 3 where the coefficient of correlation was 0.85, p<0.001. The teeth of the maxilla are more convenient for the age determination than the teeth of mandible. They are in the significant strong correlation with the known real age, and in Method 3, the coefficient of correlation is 0.78, p<0.001. Age determination of the teeth with two roots is in significant correlation with the known real age p<0.001 in relation to the determined age on the teeth with one root. The results show that sex too, is in significant correlation with the real age, p<0.001. In practice, the methods used and the results achieved in this research have been enabling the dental age estimation of human remains from mass graves after the 1991 war in Croatia.     

The use of quantitative light-induced fluorescence (QLF) to identify composite restorations in forensic examinations

There has been a large increase in the number of tooth colored restorations "white fillings" placed in recent years. An increased demand from the public for more aesthetic dental restorations causes a potential problem for forensic dentists who may find the fillings difficult to identify and hence include in postmortem odontograms. This has implications for the accuracy of dental identifications, particularly in situations where limited time is available for postmortem identification, e.g., mass casualty incidents. A new method for the detection of composite restorations is presented. Quantitative Light-induced Fluorescence (QLF) is a technique currently employed to detect small changes in enamel mineral content. An experiment was conducted to determine if the technique would afford a greater degree of contrast between composite and enamel and thus enable the accuracy of composite identification in enamel. Twenty-four previously extracted human premolars were gently cleaned with pumice and wet-and-dry paper. Twelve were subsequently randomly selected and restored on their buccal surfaces with Spectrum (a composite) following manufacturer's instructions. No attempt was made to color match the teeth and all were filled with shade B3. Twelve teeth were left unrestored. QLF and normal white light images were taken of both restored and non-restored surfaces with teeth wet and then dried. Ten forensic dentists were asked on two separate occasions (one month between each attempt) to indicate whether or not they thought the surface was: a) restored or b) unrestored. Results indicate that forensic dentists detected a significantly higher proportion (p<0.005) of filled surfaces with QLF.     

Biomedical image processing for age measurements of intact teeth

With increasing age the roots of teeth undergo sclerosis. The degree of dental root sclerosis can be demonstrated visually if light is transmitted through the specimen. However, this resultant image is only a two-dimensional (2-D) visualization which misrepresents what in truth is a three-dimensional (3-D) characteristic. We have described an image acquisition and computer processing system for imaging intact teeth, with special reference to the root transparency, which tends to progress from the root apex towards the neck of the teeth as a function of age. The components of our system involve: an energy source with light transmission through table-mounted dental specimens; an image processor with a digitizer; a step motor with a holder to rotate the tooth specimen; and a software package to computerize and reconstruct the sectional digital images. After rotating the position of the specimen, while at each rotation obtaining a 2-D image of the sample, we then can reconstruct the true 3-D cross-sectional or longitudinal morphology or both from these 2-D images. With this new approach, the reconstructed dental images represent segments from different angles of the tooth specimen. Picture element values in each image, quantitatively indicate the optical density, expressing the age dependent pattern of the 3-D anatomy in toto.     

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.     

The application of Kvaal's dental age calculation technique on panoramic dental radiographs

INTRODUCTION: Literature reports on a method for dental age calculation which is based only on radiological measurements on periapical dental radiographs: the relationship between chronological age and the two-dimensional dental pulpal size was analysed by means of multiple regression analyses. The purpose of the present study was to evaluate whether this approach could be feasible and could lead to statistically sound results with adequate repeatability when applied on panoramic radiographs. MATERIALS AND METHODS: One hundred and ninety seven panoramic radiographs were collected at random from patients of whom the age ranged from 19 to 75 years. According to the reported technique, six teeth were selected on the panoramic radiograph: in the maxilla the central and lateral incisor and second bicuspid, and in the mandibula the lateral incisor, cuspid and first bicuspid. The same exclusion criteria as in the original paper were respected. Statistical analysis was carried out in order to spot significant differences between the chronological age and the calculated age. RESULTS: When the age was calculated based on measurements of all six teeth or of all three mandibular teeth, no significant differences were found between the real age and the calculated one. In all other instances using the individual teeth separately or using all three maxillary teeth statistical analysis revealed significant differences. CONCLUSION: There appears to be no significant difference between applying the original technique on standard long-cone periapical radiographs or on orthopantomograms, especially when carrying out measurements on all six selected teeth.     

Developing permanent tooth length as an estimate of age.

Developing teeth are widely used to predict age in archaeology and forensic science. Regression equations of tooth length for age is a direct method, however, data for permanent teeth is incomplete. The aims of this study were: (a) to calculate regression equations predicting age from tooth length of all permanent teeth from birth to maturity, and (b) to evaluate the difference between radiographic and actual tooth length. The sample studied (N = 76, age range 0 to 19 years) was the Spitalfields juveniles of recorded age-at-death. Tooth length was measured from incisal tip to developing edge of crown or root of 354 dissected teeth. Data for upper and lower teeth were combined except for the lateral incisor. The least squares regression method was used to analyze the data for each tooth type; age being regressed against tooth length for prediction. For most tooth types, growth followed an S-shaped (polynomial) curve with initial fast growth and a further growth spurt around the time of mid root formation. No difference was found between radiographic and true tooth length. These regression equations provide an easy method of predicting age from any developing permanent tooth by measuring tooth length from isolated teeth or from unmagnified, undistorted radiographs.     

Comparison of Age Estimation in Japanese and Scandinavian Teeth Using Amino Acid Racemization*

Abstract: Racemization method is currently considered to be one of the most accurate methods for age estimation. There are many factors that affect racemization reaction velocities. We investigated ethnic differences in the racemization reaction velocities between Japanese and Scandinavian teeth. After a heating experiment, the Arrhenius equation was used to obtain a rate constant (k). Both groups presented almost identical velocities, indicating that there was no difference in the tooth racemization reaction between the two groups. However, because 14 of the 18 Scandinavian teeth had multiple roots, it is possible that accurate racemization rates of the teeth themselves were not reflected in the results. These findings reconfirm that the type of tooth selected is extremely important when evaluating age by racemization.     

尸体玫瑰齿现象与死因的关系

目的研究尸体玫瑰齿现象与死因的关系及其法医学意义。方法采用观察法研究各种死因的大鼠尸体玫瑰齿现象。每种死因观察10只大鼠,其中8只死后即刻取牙齿观察(非腐败组),2只死后置水中腐败出现尸臭时取牙齿观察(腐败组),观察后立即将牙齿置于酒精中浸泡,分别于不同浸泡时间再进行观察。结果各种死因非腐败组即刻取牙观察均未见玫瑰齿现象,但置酒精中浸泡后均逐渐出现玫瑰齿现象,并在浸泡4h后玫瑰齿颜色显著;腐败组取牙齿后即刻观察均见玫瑰齿现象,置酒精浸泡1h后颜色不改变;腐败组较非腐败组颜色明显。结论尸体玫瑰齿现象与死因无关,不能作为法医学鉴定死因的依据。     

Model of age estimation based on dental factors of unknown cadavers among Iranians

Two hundred and ten cadavers ranging in age from 25 to 60 were studied. Thirty subjects from each five-year interval were selected, and data were collected using the mandibular anterior and premolar teeth after extraction. Sections ranging from 0.5 to 1.0 mm were measured by a stereo microscope with a precision of 0.1 mm. The following factors were determined: attrition, periodontosis, root resorption, secondary dentine apposition, cementum apposition, and translucency of the root. Statistical analysis used the sum of ranks of the dental factors as an independent variable in a linear regression model to estimate the age of the cadaver. Among the different mandibular teeth, the sum of ranks of the first premolar factors had the best correlation coefficient with age. The sum of the dental factors presented a better model than each of the factors alone. The first premolar is recommended as the first step in the estimation of age.     

上下颌牙齿磨耗推断年龄准确性的比较

目的利用牙齿磨耗不同的分类方法分别推断上、下颌的牙齿年龄,分析各种方法推断上、下颌牙齿年龄的误差,评价上、下颌牙齿用于年龄推断的准确性。方法采用分级法与数量化法分别对164名18~46岁之间的成年人进行牙龄推断,计算出推断牙龄与实际年龄的误差,输入SPSS软件对误差的数据进行统计学分析。结果分别使用不同方法对上、下颌牙齿磨耗程度进行年龄推断的结果差别不大。结论上、下颌牙齿用于牙齿磨耗推断年龄的准确性无明显差异。     

Pink teeth in a series of bodies recovered from a single shipwreck

Pink teeth have most often been observed in victims of drowning but have also been reported in subjects who died suddenly and unnaturally. There is general agreement that there is no obvious connection between the occurrence of pink teeth and the cause of death, but the condition of the surroundings (especially humidity) must certainly play an important role in the development of the pink-tooth phenomenon. The frequency and distribution of postmortem pink coloration of the teeth have been studied among a representative sample of 52 cadavers. All the bodies were victims of a single shipwreck that occurred on March 13, 1997, in the middle of the Otranto Canal (Mediterranean Sea). The bodies were recovered from the seawater after approximately 7 months. A distinct pink coloration of the teeth was found in only 18 cadavers (13 females and 5 males) of ages ranging between 13 and 60 years. The phenomenon was more pronounced in younger individuals due to age-related changes of the root canal, less penetrable by the pigment responsible for the postmortem pink staining. By histochemical methods and autofluorescence, hemoglobin and its derivatives have been identified as the most likely pigments responsible for this postmortem process that can be considered analogous to postmortem lividity. These data are consistent with previous reports on pink teeth, indicating that the diffusion of the blood in the pulp into the dentinal tubules causes the red discoloration of the teeth. Based on the results, the pigmentation is more prominent on the teeth with single roots rather than in the posterior teeth with multiple roots.     

Forensic human identification: Investigation into tooth morphotype and DNA extraction methods from teeth

When a body is decomposed, hard tissues such as teeth may provide the only DNA source for human identification. There is currently no consensus as to the best DNA extraction method, and there is a lack of empirical data regarding tooth morphotype and condition that may impact DNA recovery. Therefore, this study sought to investigate which variables significantly improved DNA concentration, integrity and profiling success. A total of 52 human teeth were assessed, representing all tooth morphotypes from three deceased individuals. DNA was extracted using both the QIAamp® DNA Investigator Kit and the phenol-chloroform method. DNA concentration and degradation index were assessed using real time PCR, prior to conventional DNA profiling. Contrary to international guidelines promoting the use of molars, DNA profiling from molars was the least successful, with premolars, followed by canines, performing the best. The presence of fillings reduced the DNA quantity and quality obtained and may explain the poor performance of molars. DNA from the maxillae were significantly less degraded when the QIAamp® was used, although this did not influence DNA profiling success. A significant increase in DNA concentration, integrity and profiling success was observed in diseased teeth (periodontitis) compared to those without disease. This may be due to increased white blood cell presence at the site. There was no significant difference in DNA profiling success between the two DNA extraction methods. However, different teeth yielded failed DNA profiles for each extraction method, suggesting that repeated attempts, using alternative DNA extraction methods, is recommended. The recovery of additional DNA profiling information from degraded samples may help to ultimately reduce the burden of unidentified human remains.     

The relationship between the soft tissues and the skeletal detail of the mouth

The estimation of mouth width and lip thickness from the skull for facial reconstruction has traditionally relied upon scant scientific research and "rules of thumb" laid down by subjective interpretation and experience. This study tested these assumptions by taking caliper and photographic measurements of mouth width and interpupillary and interlimbus distances of 96 subjects and lip thickness and teeth height measurements of 95 subjects. The most reliable indicator of mouth width was found to be the interlimbus distance, and lip thickness was positively related to the height of the teeth. There were no differences in these relationships between men and women. Standards for predicting the lip thickness from the teeth height were suggested for White Europeans and Asians from the Indian subcontinent.     

An Evaluation of Statistical Methods for the Determination of Age of Death Using Dental Root Translucency and Periodontosis

Abstract: Lamendin and colleagues (1992) proposed to assess age‐at‐death from root translucency and periodontosis. Several teeth from the same individual were included in their study. In our work, we evaluate the reliability of their formulas without introducing this bias. Our sample was constituted of 214 individuals (114 males and 100 women) selected from the Terry collection (U.S.A.). The R² between age and both indicators is equal to 0.33 and 0.08 (p < 0.001). Based on linear regression, the mean of standard error for individual age prediction was equal to 13.67 years, and the mean interval length is equal to 53.89 years. Multinomial logistic regression and Bayesian approach failed to give satisfactory results when classifying the individuals in age categories. Therefore, the use of root translucency and periodontosis may lead to incorrect age‐at‐death assessment, and it is thus necessary to complement this approach with other techniques to assess age‐at‐death.     

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.     

The Effects of Household Corrosive Chemicals on Human Dentition*

Abstract: There is a gap in the literature concerning the chemical effects that household products may produce on human remains. The present study examines the effects of household chemical products on teeth. A total of eight chemicals were utilized for this experiment. The corrosive chemical categories include: hydrochloric acid, sulfuric acid, phosphoric acid, and sodium hydroxide. Two products with each chemical were used, each representing varying concentrations of the corrosive product. Two human teeth were allocated for emergence in the chemical throughout a 24‐h period of exposure. Results demonstrate hydrochloric acid as the most detrimental chemical to the dental samples. Sulfuric acid enacted minimal alterations to the teeth, although some etching and discoloration were noticeable. Phosphoric acid resulted in variable changes of the organic and inorganic contents of teeth. Lastly, exposure of sodium hydroxide resulted in little to no change. As hypothesized, distinct effects are observable of each chemical.     

Prosthetic restorations, dental root fillings and periodontal bone resorptions as a forensic-odontologic aid for determining the age above 18 years: A radiographic study of orthopantomograms from a group of teenagers and yount adults

The human teeth are a valuable source of information concerning identification and age calculation in forensic sciences. Dental treatment often causes permanent alteration of the teeth, which is visible on radiographs. The correlation of prosthetic restorations, root canal fillings and periodontal bone loss with chronological age has not yet been used for determining the completed 18th year of life in teenagers and young adults, e. g. for legal and anthropological purposes. The aim of this study was to determine whether the evaluation of such findings on radiographs correlates with the chronological age in teenagers and young adults. MATERIAL AND METHODS: The dental X-rays (orthopantomogram, OPG) of 1053 outpatients (age: 14 to 24 years) were avaluated. The values "prosthetically restored", "filled dental root", or "periodontal bone loss" were recorded for each tooth present. The data were then evaluated using statistical tools. RESULTS: The correlation between the number of prosthetically restored teeth and the chronological age is high. The positive predictive value of determining an age of at least 18 years proved to be very high. However, these findings are rarely present in this age group. The number of endodontically treated teeth correlated less exactly with age. On the other hand, the determination of periodontal bone loss gave reasonable positive predictive values for the threshold value "chronological age of 18 years or more". DISCUSSION: This study provides for the first time predictive values for the estimation whether a person is 18 years of age, based on the evaluation of teeth with prosthetic restorations, root canal fillings or periodontal bone loss on OPGs only. Whereas the number of patients with such findings is generally low in this age group, some of the positive findings can be used for age estimation as an adjunct to other sources of age calculation. The sole application of these criteria is not recommended, as sanitary conditions of the teeth depend on both social and individual circumstances. Therefore, the calculated values also reflect the culture of the sample studied. Finally, they are time-dependent and have to be compared to data from other populations. These results have some bearing on the field of forensic odontology.     

Measuring the distance of the wisdom teeth from the occlusal plane as forensic-odontological method for chronological age determination

As part of an epidemiological study on tooth eruption it was attempted to define easily accessible criteria for age estimation in living human beings based on the distance of the wisdom teeth from the occlusal plane. 253 cast models of 149 female and 104 male patients were used for evaluation. Due to the great variability observed in the eruption of the wisdom teeth, only a small fraction of the total number of 10,924 cast models was suitable for investigation. Only teeth with the axis being perpendicular to the plane of occlusion during eruption according to radiological and clinical findings were included. After defining these inclusion criteria, the distance of the wisdom teeth from the plane of occlusion was determined and correlated to the age of the subjects. The results confirmed the known large variability concerning wisdom tooth eruption and did not show any reliable relation between age and distance values. Nevertheless, a remarkable finding that may be relevant for forensic odontostomatology was seen in one case where the lower wisdom teeth were taller than the occlusal plane, although the female patient was younger than 14 years. The upper molars were retained and root development was incomplete.     

中国汉族6-18周岁男性牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿钙化程度推断中国汉族6～18周岁男性年龄的办程。方法通过对6568名6～18周岁汉族男性全口曲面断层影像上牙齿的钙化程度进行评分;将分级值及其对应年龄输入SPSS软件进行分析,建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本160例进行卣测,,结果同名牙齿钙化评分值侧别间秩合检验结果P〉0．05;下颌左侧恒牙钙化评分值与年龄相关分析结果r值均存0．7以上,下颌同名牙间相关系数r均在0．9以上;所建回归模型拟合优度R^2=0．828,估计值标准误为1．23岁;阿测平均洪差为0．423±0．269岁。结论本研究所建立的方法准确可靠,可用于中国汉族6～18周岁男性人群的年龄推断。