Studies of the chronological course of wisdom tooth eruption in a Japanese population

The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 549 male and 751 female Japanese subjects aged 14-26 years based on radiological evidence from 1300 conventional orthopantomograms. The results presented here provide useful data on the age of alveolar, gingival, and complete emergence of the third molars in the occlusal plane that can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.

Determination of D/L-amino acids by zero needle voltage electrospray ionisation

Ion formation may be made more efficient than in normal electrospray ionization (ESI) for certain classes of compounds, such as the polar amino acids Glu, Asn, His, Ser, Asp, Arg, Tyr and Lys, by adjusting the voltage of a normal ESI interface needle to zero voltage. For aspartic acid (Asp) the gain in signal-to-noise (S/N) ratio of the liquid chromatography/mass spectrometry (LC/MS) chromatograms obtained in the selective ion monitoring (SIM) mode (m/z 134) with zero needle potential was 40-50 times higher than detection at 4 kV. Ion formation at zero potential is likely to follow a mechanism related to sonic spray ionization. The utility of the zero needle voltage ESI was illustrated by determining the age of a human tooth by the aspartic acid epimerization method. The procedure involved separating the D- and L-aspartic acid of a tooth extract on a chiral HPLC column and detection by zero voltage ESI-MS3.

Accuracy of developing tooth length as an estimate of age in human skeletal remains: The deciduous dentition

Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.

Exchanged identities in a complex multiple homicide case. Identification and cause of death

We report a multiple homicide in Angola involving six Portuguese citizens. Immediately after the crime, four bodies were retrieved from the homicide site. Forensic autopsies were allegedly performed by local doctors and three bodies were transferred to Portugal, where they were buried with no extra expertise, presumably identified only by the examinations carried out in Angola. The two remaining bodies, presumably from sub-adults, were only discovered 1 year later. At that time, some bone samples of these two corpses were sent to Portugal. A multidisciplinary team of the National Institute of Legal Medicine (NILM) in Portugal, including forensic anthropologist and pathologists, and forensic geneticist, found out that the bodies were previously misidentified. In fact, the anthropological and genetic examinations on the remains of the two persons showed that they did not belong to a child and an adolescent but instead to two adult victims, at least one of them was supposed to be buried in Portugal since 1 year. The verification of this misunderstanding led to a series of exhumations, of the three victims previously buried in Portugal. In all, the identities were reconstructed and the cause of death could be established in four of them. A multiplicity of severe traumatic cranial injuries were detected, which were, undoubtedly due to a violent death.

Age Estimation From Root Development of Mandibular Third Molars in Comparison With Skeletal Age of Wrist Joint

Identification of the living person and the dead is of paramount importance for variety of reasons in forensic practice routinely. Age estimation is one of the prime factors employed to establish identity. Estimating age from teeth is generally reliable as they are naturally preserved long after all the tissues and even bones have disintegrated. A study was done to determine the age by root developmental changes, using the intraoral periapical radiographs of the mandibular third molars, adopting the Leif Kullman et al method. Three hundred forty-six girls and 389 boys of the age range 15-25 years, among the South Indian population of young adults from various schools and colleges in the vicinity of Dakshina Kannada and Udupi Districts and also among the patients visiting the outpatient department of Oral Medicine and Radiology, College of Dental Surgery, Manipal, were considered for this study. The subjects were roentgenographically examined to determine the age from the 7 stages of root development of the left mandibular third molar. Depending on the exact stage of root development as seen in the radiograph, the chronologic age was determined. This method sheds a new light on determining the ages of 15, 16, and 18 years, which has an immense medicolegal bearing.

Studies of the Chronological Course of Wisdom Tooth Eruption in a Black African Population

The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X-rays. In the present study, we determined the stage of wisdom tooth eruption in 410 male and 106 female Black South African subjects of known age (12-26 years) based on radiological evidence from 516 conventional orthopantomograms. Four eruption stages were determined (no emergence, alveolar emergence, gingival emergence, complete emergence). Statistical scores were determined for the individual stages separately for both sexes. The data presented here can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.

Age Estimation by a Dental Method: A Comparison of Lamendin?s and Prince & Ubelaker?s Technique

Lamendin et al. (J Forensic Sci 1992;37:1373) developed a general technique to estimate age of adults at death using two dental features: periodontosis and translucency of the tooth root. Prince and Ubelaker (J Forensic Sci 2002;47:107) modified this method, creating a formula for each sex and for different ancestries, and obtained more precise age estimations. In the present study, the validity of each method was tested in 45 males and 34 females of Spanish Caucasian origin, and a novel formula, based on Prince and Ubelaker method, was specifically developed for a population of mixed racial origin (mestizo) from Colombia, and findings obtained were again compared with those yielded by Lamendin adult dental aging technique. The Prince and Ubelaker method proved more accurate than the Lamendin technique in the Spanish Caucasian population, and our Prince and Ubelaker-based formula was also more accurate than the Lamendin et al. In both populations, the Lamendin method showed a higher mean error in estimations of the age of youngest and oldest individuals. These findings confirm the need to create specific formulas for each human group in order to obtain more accurate age estimates.

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).

[Accuracy of age estimation from orthopantomograph using Demirjian's method]

OBJECTIVE

Developing teeth are used to assess maturity and estimate age in a number of disciplines. The aim of this study was to determine the accuracy of Demirjian method (Panoramic radiographs were examined and seven mandibular teeth staged according to Demirjian's dental maturity scale) in the forensic clinical medicine.

METHODS

Tooth formation was assessed with orthopantomographs in healthy children in dental teaching hospital. There were total 828 children, with 279 boys and 549 girls, aged from 11 to 19 years. The difference between dental and real age was compared and measured, using t-test.

RESULTS

The Demirjian method overestimated age in the aged 11-16 years group and had limitations in aged group over 17 years.

CONCLUSION

The 95% confidence interval of the mean was least for mean of all developing teeth using Demirjian method (age 11-16 years).

The chronology of third molar mineralization in the Austrian population—a contribution to forensic age estimation

The aim of the present study was to determine the chronology of third molar mineralization and to establish Austrian reference data. Therefore, a cross-sectional study was undertaken by evaluating 610 panoramic radiographs in order to assess the mineralization status of the mandibular third molars of Austrian male and female individuals (275 males and 335 females) between the ages of 12 and 24. The evaluation was carried out using the eight grade scheme of Demirjian et al. (1973). Mean ages, standard deviations, standard errors and percentile distributions are presented for each stage of development. Significant differences between the left and right mandibular third molars were not found. Males reach the developmental stages earlier than females, statistically significant differences were noted in stages E and F. Both mandibular third molars were observed in the majority of the individuals of the Austrian sample (477 individuals, 78.2%). For medicolegal purposes the likelihood of whether an Austrian individual is older than 18 years or not was determined.

[Immunohistochemical proof of amelogenin in teeth--a contribution to the evaluation of the age in the identification of unknown corpses]

When a corpse is found that cannot be identified, one of the forensic tasks is to determine how old the person was when she or he died. To solve this frequently asked question in forensic practice, the enamel protein amelogenin was marked immunohistochemically in 249 extracted teeth. Amelogenin is already produced during prenatal development and is gradually used up throughout life into old age. Hence, the demonstrability decreases with age. The extent of the labelling can be quantified by measuring the mean optical density (MOD). While it is not possible to determine the age on the basis of the mean optical density measurements alone, logistic regression of the MOD together with dichotomisation of the teeth according to age allows statements as to whether the person was younger or older than 30 years.

The application of amino acid racemization in the acid soluble fraction of enamel to the estimation of the age of human teeth

Estimation of age-at-death for skeletonised forensic remains is one of the most significant problems in forensic anthropology. The majority of existing morphological and histological techniques are highly inaccurate, and show a bias towards underestimating the age of older individuals. One technique which has been successful in forensic age estimation is amino acid racemization in dentine. However, this method cannot be used on remains where the post-mortem interval is greater than 20 years. An alternative approach is to measure amino acid racemization in dental enamel, which is believed to be more resistant to change post-mortem. The extent of amino acid racemization in the acid soluble fraction of the enamel proteins was determined for modern known age teeth. A strong correlation was observed between the age of the tooth and the extent of racemization. No systematic bias in the direction of age estimation errors was detected. For the majority of teeth analyzed, the presence of dental caries did not affect the results obtained. In a minority of cases, carious teeth showed a higher level of racemization than would be expected given the age of the individual. These results indicate that amino acid racemization in enamel has the potential to be used in age estimation of skeletal remains.

Age estimation in children by measurement of open apices in teeth: a European formula

The aim of the present paper was to improve and expand research with a larger number of children from various European countries and to provide a common formula useful for all these countries. Orthopantomographs taken from 2,652 European Caucasian children (1,382 boys, 1,270 girls) aged between 4 and 16 years were analyzed. The children came from Croatia, Germany, Kosovo, Italy, Slovenia, Spain, and the UK. Following the pilot study, subjects' age was modeled as a function of gender (g), morphological variables (predictors) x 5(second premolar), s (sum of normalized open apices) N 0, and the first-order interaction between s and N 0. The results showed that all these variables contributed significantly to the fit, so that all were included in the regression model, yielding the following linear regression formula: Age = 8.387 + 0.282 g - 1.692 x 5 + 0.835 N 0 - 0.116 s - 0.139 s x N 0, where g is a variable, 1 for males and 0 for females. The equation explained 86.1% (R2 = 0.861) of total deviance. The median of the residuals (=observed age minus predicted age) was -0.114 years, with (RefB.2) interquartile range = 1.22 years.

Thickness of the dental (radicular) cementum: a parameter for estimating age

The present study used 127 extracted teeth from people aged 16 to 90 years old. The aim of this research was to verify the reliability of the method using a single dental parameter based on the correlation of the radicular cementum thickness and the chronological age of the subject. The thickness was measured both on the lingual side and on the vestibular side of the tooth, at two different levels: apex and one third of the root length from the apex. The data were reported through a Cartesian graph with the X-axis showing the cementum thickness and the Y-axis showing the subject's age. The correlation between age and the increase of the cementum thickness is more statistically evident when the measurement is taken at the apex (R2=0.67), in comparison with the measurement taken at approximately one third of the root length from the apex (R2=0.56).

Dental age in Central Poland

Precise evaluation of the developmental stage of a child is an integral part of both diagnosis and treatment of pediatric patients; it is also essential in forensic medicine and dentistry. Among radiological methods for dental age estimation in children the Demirjian's method is widely used, however original standards elaborated for the French-Canadian population are mostly not suitable for other populations. The aim of the study was to compare the dental age of children from the region of Mazovia (Central Poland) with the developmental standards presented by Demirjian, to analyse sexual dimorphism of dental age in the studied group and to estimate validity of the Demirjian's standards for the studied Polish population. The material consisted of clinical files and panoramic X-ray images of 994 children aged from 6 to 16 in good general health, without development impairments. Chronological ages of the patients were established. Next dental ages were estimated by means of the Demirjian method based on developmental maturity of seven left mandibular permanent teeth. It was found that the standards were significantly different from the chronological ages in the studied population, which means that dental development was considerably accelerated. The most significant acceleration was observed in girls aged 11 and 12, as well as in 13-year-old boys; in both groups a considerable acceleration of the dental age was seen in 6-year-olds. No statistically significant differences between dental ages of girls and boys were observed in particular age groups. There were devised gender-specific equations allowing for adaptation of original Demirjian's scores for estimation of dental age in the population of Mazovia (Central Poland). In conclusion, the developmental standards used by Demirjian are not suitable in the case of the population of children of Central Poland. Therefore, it is necessary to establish new tables for this population.

The measurement of open apices of teeth to test chronological age of over 14-year olds in living subjects

Age determination in living subjects is a problem of increasing interest in our community, due to the increasing numbers of individuals without identification papers, who have immigrated illegally or committed crimes, and for whom it is necessary to verify whether they have reached the age of 14 years in order to be charged legally. Although the most widespread methods for age estimation refer to skeletal or dental analysis, these methods do present some drawbacks for identification of the age of 14. The aim of the present study is to discriminate between children who are or are not 14 years of age or older by measuring the open apices of teeth. We evaluated the OPGs of 447 persons aged between 12 and 16 years, of Italian, Croatian and Slovenian nationality. For each individual, dental maturity was estimated using the number of the seven left permanent mandibular teeth with root development complete, and normalized measurement of the open apices of the third molar. The results revealed that an individual is considered to be 14 years of age or older if all seven left permanent mandibular teeth have closed apices and the normalized measurement of open apices of the third molar is lower than 1.1.

Age Estimation of Korean Adults by Occlusal Tooth Wear

The aim of the present study was to evaluate the validity of the modified Kim's scoring system as a practical method of recording occlusal tooth wear and estimating age. For this purpose, 1092 pairs of maxillary and mandibular full-arch casts were randomly selected, scored, and analyzed. The results showed that the modified Kim's scoring system had excellent reliability, and that occlusal tooth wear had a positive correlation with age. Tooth wear scores of all teeth except the two lower central incisors were higher in males than in females. Calculating tables for age estimation were designed by multiple linear regression analysis. Estimated ages were within +/-5 years of actual ages in 63.5% of male subjects, and 64.0% of female subjects. The accuracy of age estimation was increased when the subjects were divided into two age groups and data were re-analyzed. Collectively, it was shown that the modified Kim's scoring system is a reliable and accurate method for age estimation, and that the data from these 1092 individuals can be used as a standard for age estimation of Korean adults.

Cervical vertebral and dental maturity in Turkish subjects

INTRODUCTION

The aim of this study was to investigate the relationships between the stages of calcification of teeth and the cervical vertebral maturity stages in Turkish subjects.

METHODS

A retrospective cross-sectional study was designed. The final study population consisted of 590 Turkish subjects. Statistical analysis of the data was performed with computer software. Spearman rank order correlation coefficients were used to assess the relationship between cervical vertebral and dental maturation. For a better understanding of the relationship between cervical vertebral maturation indexes and dental age, percentage distributions of the studied teeth were also calculated.

RESULTS

Strict correlations were found between dental and cervical vertebral maturation of Turkish subjects. For males, the sequence from lowest to the highest was third molar, central incisor, canine, first premolar, second premolar, first molar, and second molar. For females, the sequence from lowest to the highest was third molar, canine, second premolar, first premolar, central incisor, first molar, and second molar.

CONCLUSIONS

Dental maturation stages can be used as a reliable indicator of facial growth.

On the applicability of secondary dentin formation to radiological age estimation in young adults

The literature provides linear regression formulas for dental age estimation that is based on radiological two-dimensional measurements of the pulp size. The aim of the present study was to explore whether the previously presented regression formulas could lead to statistically sound results and to appropriate repeatability when applied to young individuals. Orthopantomograms (OPGs) of 44 Austrian individuals, aged between 13 and 24 years, were selected at random. In accordance with the reported method, six teeth on each OPG were chosen to carry out the measurements. Statistical analysis was performed in order to assess the difference between the estimated and the true chronological age. The regression formulas reported by Kvaal et al. (1995) led to a consistent underestimation; the regression formulas reported by Paewinsky et al. (2005) resulted in a constant overestimation of age. The statistical analysis of intraobserver and interobserver variation revealed a variation width below 2%, respectively.

A Test of the Differential Accuracy of the Maxillary Versus the Mandibular Dentition in Age Estimations of Immature Skeletal Remains Based on Developing Tooth Length

Liversidge and colleagues developed a method for predicting the age of immature skeletal remains based on the length of developing teeth. This quantitative method combines dental data from both jaws, except for the permanent lateral incisor, and because there are reasons to suspect that these two types of data are not identical and should not be combined, it raises concerns regarding the accuracy of the technique when applied differently to each jaw. In this study, the differential accuracy of the method was test when applied to the maxillary and mandibular dentition. The test sample is comprised of 57 Portuguese subadult skeletons of known age at death. Results suggest an overall high consistency between estimates obtained from both jaws, but for the permanent dentition only. In the deciduous dentition the age estimates obtained from the maxillary teeth tend to be greater than the age estimates obtained from the mandibular pair, and the differences are significant for the incisors and canine. Additionally, ages obtained from the maxillary deciduous canine also differ significantly from true chronological age. In the permanent dentition there were no differences between the ages provided by both jaws but both the maxillary and mandibular second molars show a significant tendency to underestimate true chronological age. Although this study cannot validate completely the method presented by Liversidge and colleagues, it does provide an important test to its accuracy and calls for further research into its overall performance, particularly with respect to the results obtained from both jaws.

Third molar development in the estimation of chronologic age in american blacks as compared with whites

Third molar (M3) development determined from dental radiographs in American blacks (African Americans; n=637) aged 14-24 years was contrasted against American whites (n=563) from a previous study using the method of Demirjian et al. Differences were assessed using descriptive statistics and the parametric proportional hazards model. For each developmental stage, the probability of an individual being at least 18 years old was evaluated. As in other M3 studies, there were highly significant modal differences, but the age ranges at each stage overlapped considerably. Black-white differences were highly significant with developmental stages occurring in blacks a year or so earlier. Gender differences also varied significantly, both with increasing age and between races. The empirical likelihood that an African American male with fully developed M3's is at least 18 years old is 93% and that for African American female is 84%. Corresponding risks for whites are 90% and 93%.

Age Estimation by Pulp/Tooth Ratio in Canines by Peri-Apical X-Rays

Estimation of age in individuals has received considerable attention in forensic science, in which it is a widely used method for individual identification, together with paleo-demographic analyses to establish mortality patterns in past populations. The present investigation, which is a continuation of a previously published pilot study, was conducted to examine the possible application of the pulp/tooth area ratio by peri-apical images as an indicator of age at death. A total of 200 peri-apical X-rays of upper and lower canines were assembled from 57 male and 43 female skeletons of Caucasian origin, aged between 20 and 79 years. They belong to the Frassetto osteological collection of Sassari (Sardinia) and are housed in the Museum of Anthropology, Department of Experimental and Evolutionistic Biology, University of Bologna. For each skeleton, dental maturity was evaluated by measuring the pulp/tooth area ratio on upper (x(1)) and lower (x(2)) canines. Very good agreement was found between intraobserver measurements. Statistical analysis was performed in order to obtain multiple regression formulae for dental age calculation, with chronological age as dependent variable, and gender, and upper and lower canines as independent variables. Stepwise regression analysis showed that gender did not contribute significantly to the fit (p=0.881) whereas variables x(1) and x(2) and the first-order interaction between them did. These two variables explained 92.5% of variations in estimated chronological age and the residual standard error was 4.06 years. Lastly, two simple linear regression equations were obtained for age estimation using canines from the maxilla and mandible separately. Both models explained 86% of variations in estimated chronological age and allowed an age-at-death estimate with a residual standard error of about 5.4 years.

Radiographic evaluation of third molar development in relation to chronological age among Turkish children and youth

A sharp increase in forensic age estimation of living persons has been observed in recent years. However, ethnic populations residing in different countries have been insufficiently analyzed. According to 2004 data compiled by the Essen-based Turkey Research Center, there are 3.8 million Turkish people living abroad, and 3.2 million of them reside in European Union countries. Despite the high number of Turks living abroad, little is known about third-molar development for forensic application in this population. Hence, it was considered worthwhile to determine the developmental stages of the third molar in a group of Turkish population, to assess chronological age estimation based on the developmental stages, and to compare third molar development according to sex, age and location. Orthopantomograms of 1134 Turkish patients, ages 4-20 years were examined and third-molar developmental stages were evaluated based on Demirjian's classifications. Orthopantomograms were scored by two different observers, and Wilcoxon matched-pairs signed-ranks test used to test intra- and inter-observer reliability revealed a strong agreement between both intra- and inter-observer measurements. Linear regression analysis was performed to correlate third-molar development and chronological age, and further statistical analysis was performed to determine the relation between sex, age and location. Results showed a strong linear correlation between age and molar development (males: r(2)=0.57; females: r(2)=0.56). Mineralizations of left and right third molars were compared using Wilcoxon tests, and no statistical differences were found. No significant differences were found in third-molar development between males and females. Mandibular third molar crypt formation was observed in 2.4% of patients at age seven and maxillary third molar crypt formation was observed in 1.3% of patients at age seven. A strong correlation was found between third-molar development and chronological age. Among the Turkish population, third molar crypt formation is observable at as early as 7 years in both the mandible and maxilla. Agenesis can be determined conclusively if no radiolucent bud is present by age 14.

Usefulness of Combining Clinical and Radiological Dental Findings for a More Accurate Noninvasive Age Estimation

The aim of this study was to establish correlations of clinical and radiological dental findings, alone or in combination, with chronological age in adults. Dental findings and orthopantomograms of 984 patients (aged 20-60 years; 524 females/460 males) were analyzed. DMF-T index and distance (alveolar bone level, ABL) between cemento-enamel junction and alveolar bone margin were recorded. Additionally, clinical and radiological findings at each tooth crown and root were collected according to the actual status of destruction and restoration, and a total score for each dentition (TSD) was calculated. After univariate correlation analysis, correlation coefficients for ABL and TSD were improved by using square root (sqrt). However, the determination accuracy was still not satisfactory; 90% of the residuals were in the range of about +/-10. The present study showed that clinical and radiological dental findings could not be used, not even in combination, for accurate age estimation as a single method, but that they could support other methods.