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.     

Application of a modified stage classification in evaluating wisdom tooth eruption in a German population

The evaluation of the eruption status of the wisdom teeth constitutes a significant component of the spectrum of dental methods available for purposes of forensic age diagnostics. In the present study, the status of wisdom tooth eruption was identified in 606 conventionally created orthopantomograms of 515 female and 91 male Germans, divided by sex and tooth, using a modified classification comprising four stages. Instead of the original stage C (gingival eruption) which cannot always be reliably identified on X-ray images of suboptimal quality, stage C of the modified classification was considered reached when the erupting wisdom tooth had reached at least half the length of the crown of the adjacent second molar, without however having yet reached the occlusal plane. The new stage classification is especially recommended for age estimation based on X-ray images in which a conclusive delimitation of the gingiva is not possible.     

Age estimation of unaccompanied minors. Part II. Dental aspects

Recent years have brought a worldwide increase in cross-border migration due to a globalized economy and ongoing belligerent conflicts. As a result, the percentage of foreigners among the general population has steadily increased not only in Germany, but also in other countries. This trend has triggered a growing demand for forensic medicine to assess the age of adolescents and young adults. The individuals examined here are unaccompanied minors without valid identification documents who do not know their age or else are suspected of not giving their correct age. The mineralization of third molars is the main criterion for dental age estimation of living subjects in the relevant age group. To date insufficient knowledge has been obtained about how ethnic origin can influence tooth mineralization. This, however, constitutes a restraint on the reliability of age estimates and hence on the forensic value of information essential to legal security. A comparative study was conducted to present comparative data on third molar mineralization in a Caucasoid, Mongoloid and African sample. In conclusion, forensic age estimates of living subjects would be more powerful tools if population-specific standards were applied to evaluations of wisdom tooth mineralization. Since the mineralization of third molars is usually completed by the age of 19 or 20 years, this feature cannot be used to ascertain whether a person has attained the forensically relevant age of 21 years. The question was whether determination based on an orthopantomogram of a combination of features relevant to dental age estimation of adults supplies forensically useful information for ascertaining whether a person has attained 21 years of age. The features considered include the DMFT index of all permanent teeth, the DMFT index of all permanent teeth excluding third molars and the DFT index of third molars projecting beyond the occlusal plane. It can be concluded that an evaluation of the variations of the DMFT index does not by itself yield sufficient data to determine with the accuracy required in criminal proceedings whether a person has attained 21 years of age. An additional X-ray examination of the medial clavicular epiphyseal cartilage is, therefore, strongly recommended when assessing whether a person is over 21.     

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.     

Age estimation in small children: reference values based on counts of deciduous teeth in Finns

The eruption of teeth in the mouth is suitable for age estimations during the period when teeth are actively emerging, in the deciduous dentition phase approximately from the age of 6 months to 2.5 years. Estimations of age can be performed simply by counting the number of teeth in the mouth. Reliability of the estimates depends on the reference data available and each population group should preferably have its own standards. In the present study timing of eruption of successive deciduous teeth was studied longitudinally in 129 Finns. The dates of clinical eruption of deciduous teeth were recorded by mothers and checked by dentists. In 40 of the 129 children emergence ages of at the most the four last teeth were based only on semiannual registrations performed by dentists. The main purpose was to provide normal timetables of tooth eruption in small children in forms that are practical in estimations of dental age. No sexual dimorphism existed in the timing of clinical eruption of successive deciduous teeth. The mean age corresponding to the presence of one tooth in the mouth was 7.1 months (S.D.=1.78) and that corresponding to tooth count 19 was 27.8 months (S.D.=3.99). If the chronological age is known, the presented distributions and means with variations make it possible to estimate the degree of advancement or delay in a child’s dental development. If the age of the child is not known, the mean and median ages can be used for estimations of chronological age. However, estimations of age should not be based only on tooth counts because of marked variation also within this homogeneous group.     

Objective measurement of dental color for age estimation by spectroradiometry

Age-related changes in tooth color have been described previously, however, the use of dental color for age estimation in forensic odontology has been limited due to the difficulty of measuring color objectively. This study presents an objective method for determining dental color to estimate the age of an individual. Dentine color in 250 teeth from patients ranging in age from 10 to 89 years was determined by spectroradiometry. Color measurements were performed as suggested in the CIE 1931 (International Commission on Illumination). Chromaticity coordinates (x, y, z), luminance (Y), whiteness index (WIC, Z%, WIC) and yellowness index (YI) were obtained. Correlations between these colorimetric variables and aging were established by linear regression analyses. All the variables fit the mathematical model with correlation coefficients ranging from 0.53 to 0.75. This method of color measurement produced an expected associated error of calibration averaging 13.7 years about the mean estimated values, at a 70% level of confidence. Two different multiple regression models for dental age estimation were tested, and variables that made the greatest contributions to age calculation were identified. To determine the effect of postmortem interval on tooth color and its influence in age estimation, 37 teeth obtained from human skeletal remains buried during an interval ranging from 21 to 37 years were also studied. In this material, the correlation between age and dental color measured by spectroradiometry was weaker than in fresh extracted teeth.It is concluded that determination of dentine color by spectroradiometry is a potentially useful objective method to estimate age in forensic studies in combination with other methods.     

Age estimation in small children: reference values based on counts of deciduous teeth in Finns

The eruption of teeth in the mouth is suitable for age estimations during the period when teeth are actively emerging, in the deciduous dentition phase approximately from the age of 6 months to 2.5 years. Estimations of age can be performed simply by counting the number of teeth in the mouth. Reliability of the estimates depends on the reference data available and each population group should preferably have its own standards. In the present study timing of eruption of successive deciduous teeth was studied longitudinally in 129 Finns. The dates of clinical eruption of deciduous teeth were recorded by mothers and checked by dentists. In 40 of the 129 children emergence ages of at the most the four last teeth were based only on semiannual registrations performed by dentists. The main purpose was to provide normal timetables of tooth eruption in small children in forms that are practical in estimations of dental age. No sexual dimorphism existed in the timing of clinical eruption of successive deciduous teeth. The mean age corresponding to the presence of one tooth in the mouth was 7.1 months (S.D.=1.78) and that corresponding to tooth count 19 was 27.8 months (S.D.=3.99). If the chronological age is known, the presented distributions and means with variations make it possible to estimate the degree of advancement or delay in a child's dental development. If the age of the child is not known, the mean and median ages can be used for estimations of chronological age. However, estimations of age should not be based only on tooth counts because of marked variation also within this homogeneous group.     

Estimation of the age of an individual based on times of eruption of permanent teeth

This is a community based study of the times of eruption of permanent teeth to establish the age of an individual. The study is based on dental examination of 1008 subjects in the age group 5-14 years, residing in Tirupati, Andhra Pradesh, India. The median age of eruption was computed based on the concept of "Ex" which is defined as the age at which a specified percentage of individuals show eruption of a given permanent tooth. The median age "E50" was computed by transformation of percentages to probits and plotting a graph between age and probits. E50 was computed graphically corresponding to a probits value of 5.0 or 50%. A mathematical regression equation [Kusri's] was computed for each graph. The age of an individual can be computed based on the E50 value of the permanent tooth which erupted last. The probability of the given individual being above or below the assessed age can be estimated by referring to graph and probit transformation table.     

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.     

The applications of MicroCT in studying age-related tooth morphological change and dental age estimation: A scoping review

Conventional dental age estimation relies on destructive methods such as sectioning and staining, which are unpreferable when the tooth is required for evidential or archeological preservation. MicroCT is a non-destructive, high-resolution imaging technique that allows for accurate morphometrical measurement. Although microCT technology has been applied in a variety of dental studies, studies focusing on dental age-related change and dental age estimation based on microCT imaging remain lacking. Based on the question: “How has microCT technology been applied in studying human age-related tooth morphological change and dental age estimation studies?”, the authors conducted a scoping review in accordance with the Arksey and O'Malley (2005) and the PRISMA-ScR guidelines. A literature search using five major scientific databases identified 452 articles, with 11 full-text articles being eligible to be included in the scoping review. Furthermore, 6 out of the 11 studies performed dental age estimation modeling. An overview of the parameters used in the selected articles revealed a variety of tooth characteristics, such as pulp cavity to whole tooth volume ratio, secondary dentin, as well as the diameter of root canal orifice. The findings of this scoping review highlight the extent microCT is used in studying dental age-related changes, as well as the effectiveness of microCT in dental age estimation studies. This review serves as a guide for future forensic odontology age estimation studies.     

Tooth eruption times of permanent teeth in male and female adolescents in Niedersachsen

The aim of this study was to determine the eruption times of permanent teeth, excluding third molars, in a defined area population of a country district in Lower Saxony. The authors investigated 2495 oral findings of 664 patients (male 315, female 349) in a longitudinal study. The minimum age was 3.00 years and the maximum age 24.00 years. The dental findings were collected over a period of about 20 years (1980-2002). The oral findings per child/adolescent were assessed between one and 16 times. The eruption times of teeth in females are earlier than those for the same teeth in males. Further, the permanent dentition in females is completed earlier than in males. The tooth eruption occurs symmetrically in both jaws. The comparison of both jaws revealed a slightly advanced eruption of the lower jaw teeth for both sexes. There is a noteworthy change in the eruption sequence of the teeth. In contrast to other reports we determined that the eruption of the canine proceeds the eruption of the second premolar. We found no acceleration of the dentition when compared to other reports and confirmed the rules of tooth eruption in man. Oral examination of teeth is a simple tool to calculate tooth eruption intervals. This first investigation on a population of Lower Saxony revealed a change in the eruption sequence of permanent teeth. The findings are relevant for dental treatment planning and should be reconfirmed at certain intervals.     

Age Estimation Based on Pulp Cavity to Tooth Volume Ratio Using Postmortem Computed Tomography Images

Pulp cavity size is known to decrease with age and can therefore serve as an indicator for age estimation. Here, we evaluated whether reconstructed images of multidetector‐row computed tomography (MDCT) acquired before forensic autopsy are useful for estimating age at death. Images of 136 mandibular first premolars obtained from bodies of known age at death were analyzed, and the volume of the regions corresponding to pulp cavity and that of the whole tooth were determined using a voxel counting function. The pulp cavity was clearly distinguishable from dental hard tissue on the reconstructed images when using a cutoff value of 1400 Hounsfield units. Regression analysis adjusted for sex showed that estimated age correlated significantly with the pulp cavity to tooth volume ratio (r = 0.76). MDCT is gaining more widespread use in forensic medicine, and analyzing dental images to obtain parameters for age prediction is a practical approach for postmortem identification.     

Age estimation by occlusal tooth wear

The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individual's age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation.     

Forensic age estimation on digital X-ray images: Medial epiphyses of the clavicle and first rib ossification in relation to chronological age

In recent years, there has been a renewed interest in forensic sciences about forensic age estimation in living subjects by means of radiological methods. This research was conducted on digital thorax X-rays to test the usefulness of some radiological changes in the clavicle and first rib. The sample consisted in a total of 123 subjects of Spanish origin (61 men and 62 women; age range: 5-75 years). From all subjects, a thorax posterior-anterior radiograph was obtained in digital format. Scoring for fusion of medial epiphyses of the clavicle was carried out by Schmeling's system and ossification of the costal cartilage of the first rib by Michelson's system. Degree of ossification and epiphyseal fusion were analyzed in relation with known age and sex of these subjects. The results give a minimum age of >20 years for full fusion of the medial epiphysis of the clavicle (Stages 4 and 5). Concerning the first rib, all subjects with the final Stage 3 of ossification were above 25 years of age. These results suggest that the first rib ossification might become an additional method to the ones so far recommended for forensic age estimation in subjects around 21. New research would be desirable to confirm this suggestion.     

Age estimation of Korean children based on dental maturity

The aim of this study was to evaluate the relationship between age and dental maturity and to establish the standard database of dental maturity based on the Demirjian's stages, which can be used for the age estimation of Korean children. For this purpose, dental maturity was measured by the Demirjian's stages on a randomly selected sample of panoramic radiographs taken from 2706 patients between 1 and 20 years of age and analyzed by multiple linear regression analysis based on the method of least squares. The results showed that, except for the third molars, the development of permanent teeth in Korean children was more advanced in females. The Demirjian's stage G of the second molar appeared last in both male and female subjects by age 18, showing 95th percentile at age in the male and female subjects between 16.7-17.4 years and 17.1-17.3 years, respectively. Coefficients of determination (r(2)) of the Demirjian's stages relative to age in regression analysis were 0.9721 in male and 0.9740 in female subjects. The standard error was 0.63 years in male and 0.62 years in female subjects. The estimated age according to regression analysis was within +/-1.0 year of the actual age in 92.0% of male and 92.5% of female subjects. Collectively, the data of the present study can be used as a reference for dental maturity and a standard for age estimation of Korean children.     

Age determination of an unknown body in early adulthood

The authors report on the estimation of the age of an unidentified deceased adolescent in connection with the body's identification. A physical examination by a forensic physician and an examination by a forensic dentist, including determination of the dental status and an X-ray of the teeth were used to estimate the age. In addition, an X-ray of the left hand as well as an X-ray and MRT scan of the clavicles were carried out by forensic radiologists. Combining the results of the individual examinations, the age of the deceased was estimated to range between 18 and 21 years. In the course of the police investigation it was found out that the deceased was 20 years and 7 months old. This has led to the conclusion that combined use of methods allows the age even of adolescents to be determined with relatively high accuracy and a minimum of time and effort.     

Reliability of the methods applied to assess age minority in living subjects around 18 years old. A survey on a Moroccan origin population

We present a review of a population of 114 immigrant Moroccan males for which an age estimation was requested. The subjects' real chronological age was confirmed by the Moroccan Embassy in Spain. The confirmed age range was between 13 and 25, with an average age of 18.1 years and a standard deviation of 2.03. The following tests were performed to arrive at the forensic estimation of age: general physical examination, carpus X-ray (Greulich and Pyle method) and dental orthopantomography to determine the degree of maturity of the third inferior molars (Demirjian's method). Carpus X-ray (skeletal age) was the most useful method, followed by Demirjian's method (dental age), as prediction factors of a chronological age of over or under 18. The combination of skeletal and dental age variables represented a significant improvement in the prediction of the chronological age of the subjects in this population, reducing the number of ethically unacceptable test errors to a minimum.     

The identification of a dismembered human body: a multidisciplinary approach

A criminal case was directed to a multidisciplinary forensic team for identification, concerning a victim whose head, having two gunshot wounds, had been separated by a sharp instrument and was recovered 6 months later. The purpose of this research was to determine the sex and age of the victim for human identification. Primarily, macroscopic examination of the skull, tooth, and DNA analysis was conducted for sex determination. A rough assessment of age was made from the skull based on anthropological findings, however a more definitive result of age estimation was determined utilizing dental morphology. The dental data showed an age range of 32-37 from the mineral examination and the formulation of microscopic measurements. The results obtained from the skull and dental analysis matched with the physical characteristics of the victim's body, the known personal data of this person, and with the superposition of the photos gathered by a formal request. Besides, the result of DNA profiling of the victim showed male gender and direct relationship with the victim's presumed wife and daughter. Generally, research on human identification consists of sex and age determination. The sex characteristics can be precisely proved from DNA tests. However, age can be estimated by skeletal, and dental analysis. In this case the performed sex and age analysis lead the research to the selective matching of the missing person's identity.     

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.     

Third molar development according to chronological age in populations from Spanish and Magrebian origin

Spain is frequently the entrance country into the European Union for undocumented immigrants, especially those from the Magreb (Northern Africa). Forensic age estimates for these persons are difficult because systematic studies of dental maturity are lacking. Three different populations were analyzed to determine the pattern of development of third molars as a tool for age estimation in people of different ethnic and geographic origin. Orthopantomograms from two different populations of Spanish origin (Galicia in northwestern continental Spain, and Ceuta, a Spanish province in Northern Africa) were compared to radiographs of molars from a Magrebian population (Northern Africa) resident in Ceuta. Orthopantomograms were obtained from a private dental clinic (n=344) in Galicia and from the Public Oral Health Services (n=228) in Ceuta. We looked for differences in third molar mineralization (determined with the Demirjian scale) that might serve as age indicators (older versus younger than 18 years). Differences in maturation patterns were found between sexes and populations of origin. Mineralization of tooth 38 was more advanced in males than females among subjects 18 years of age and older in all three populations. Moreover, mineralization of tooth 38 in subjects aged 18 years and older was significantly slower in the Spanish-Galicia population than in the Magrebian-Ceuta population. We found no significant differences between Magrebian and Spanish individuals from Ceuta. We conclude that differences in tooth 38 mineralization may be related more with socio-geographical than ethnic origin (ancestry), and thus constitute evidence of the relevance of socio-geographic rather than genetic factors in third molar development. We used ROC analysis to determine the accuracy of the examiner's ability to correctly estimate age as younger or older than 18 years. The results suggest that Demirjian stage for tooth 38 can be considered a good indicator of age in all three populations.