Evaluation of chronological age based on third molar development in the Spanish population

A cross-sectional study was carried out to assess chronological age estimation based on the stages of third lower molar development, following the eight stages (A–H) method of Demirjian et al. The final sample consisted of 1,054 orthopantomograms from Spanish individuals of known chronological age (range 14–21 years) and gender (462 males and 592 females). Results showed a stronger correlation for males (r²=0.54) than for females (r²=0.45). Root formation occurred earlier in males than females, in stages 5, 6 and 7. The mean difference between chronological and estimated age was –0.10 years (±1.23 SD) for left third molar, and –0.07 years (±1.22 SD) for right third molar, with slight variations regarding sex. Comparative tables are provided regarding medicolegal questions concerning age 18 prediction in the Spanish population, showing that legal age is reached in stage 7 (G) by women and in stage 8 (H) by men. No differences have been observed between sides (p<0.0001). Differences were observed between Spaniards and other previously studied populations. Third molar maturity takes place earlier in the Spanish than French-Canadian, Scandinavian, American, German, Japanese and South African populations and is more similar to US Hispanics in root development.     

Validation of common classification systems for assessing the mineralization of third molars

One major criterion for dental age estimation is the evaluation of third molar mineralization. There are various methods for evaluating tooth mineralization based on classification by stages. The aim of the present work is to assess the validity of the common classification systems. To this end, we analyzed 420 conventional orthopantomograms of German females aged 12–25 years old. The mineralization status of tooth 38 was determined using the stages defined by Gleiser and Hunt, Demirjian et al., Gustafson and Koch, Harris and Nortje and Kullman et al., respectively. Of the methods tested, the most accurate results were obtained with Demirjian et al.s classification system, which performed best not only for observer agreement but also for the correlation between estimated and true age. It is argued that this is due to the fact that Demirjian et al.s classification is based on a sufficient number of stages which are defined independently of speculative estimations of length. This leads to the conclusion that the method devised by Demirjian et al. should be used for evaluating the mineralization of third molars for purposes of forensic age determination.     

Age estimation using third molar maturation based on Demirjian’s criteria

Dental age estimation is routinely used in human identification, in both the living and the dead. Teeth follow a predictable pattern of eruption and maturation that can be assessed radiographically in the living, allowing experts to estimate an individual’s age. Third molars develop much later than the other permanent teeth, and can be used to estimate age of individuals nearing the age of maturity. Ability of third molar maturation when graded using Demirjian’s method in ascertaining whether an individual has attained the medicolegal ages of 16 and 18 years has not yet been verified. The present study involved assessing the third molar maturation of 220 individuals of a training set using Demirjian’s scoring system, generating regression models to estimate age using the third molar maturity scores, applying these models on a test set of 40 individuals, and calculating the mean difference (MD) and the mean absolute error (MAE) between the chronological and estimated ages of the test set participants. It was observed that the lowest mean difference and mean absolute error was observed for the maturation of the left mandibular third molar (MD = 1.05 years, MAE = 2.09 years). Boxplots generated in the study report that the third molar maturation stages given by Demirjian can identify whether an individual has attained the medicolegally significant ages of 16 and 18 years of age.     

Forensic age estimation in living subjects: the ethnic factor in wisdom tooth mineralization

Radiological assessment of the mineralization stage of third molars is a major criterion for age estimation of living people involved in criminal proceedings. To date insufficient knowledge has been obtained about how the ethnic origin can influence tooth mineralization. A comparative study of wisdom tooth mineralization was carried out on three population samples: one German, one Japanese and one South African. To this end, 3,652 conventional orthopantomograms were evaluated on the basis of Demirjians stages. The Japanese subjects were on average 1–2 years older than their German counterparts upon reaching stages D–F, whereas the South African subjects were on average 1–2 years younger than the Germans when displaying stages D–G. To enhance the accuracy of forensic age estimates based on wisdom tooth mineralization we recommend the use of population-specific standards.     

Comparative study on the effect of ethnicity on wisdom tooth eruption

The current knowledge base for evaluating the influence of ethnic origin on wisdom tooth eruption is still inadequate. We therefore analyzed and compared the chronology of wisdom tooth eruption in three ethnic populations—German, Japanese, and black South African—based on evidence from 2,482 conventional orthopantomograms. The investigated German population ranked in the middle in terms of the age of wisdom tooth eruption. The black South African population was the fastest and the Japanese population the slowest in terms of reaching the respective eruption stages. Population-specific reference data should be used when evaluating wisdom tooth eruption for the purpose of forensic age estimation.     

Two new oro-cervical radiographic indexes for chronological age estimation: A pilot study on an Italian population

Chronological age (CA) plays a fundamental role in forensic dentistry (i.e. personal identification and evaluation of imputability). Even though several studies outlined the association between biological and chronological age, there is still great variability in the estimates. The aim of this study was to determine the possible correlation between biological and CA age through the use of two new radiographic indexes (Oro-Cervical Radiographic Simplified Score – OCRSS and Oro-Cervical Radiographic Simplified Score Without Wisdom Teeth – OCRSSWWT) that are based on the oro-cervical area. Sixty Italian Caucasian individuals were divided into 3 groups according to their CA: Group 1: CAG 1 = 8–14 yr; Group 2: CAG 2 = 14–18 yr; Group 3: CAG 3 = 18–25 yr; panorexes and standardised cephalograms were evaluated according Demirjian's Method for dental age calculation (DM), Cervical Vertebral Maturation method for skeletal age calculation (CVMS) and Third Molar Development for age estimation (TMD). The stages of each method were simplified in order to generate OCRSS, which summarized the simplified scores of the three methods, and OCRSSWWT, which summarized the simplified DM and CVMS scores. There was a significant correlation between OCRSS and CAGs (Slope = 0.954, p < 0.001, R-squared = 0.79) and between OCRSSWWT and CAGs (Slope = 0.863, p < 0.001, R-squared = 0.776). Even though the indexes, especially OCRSS, appear to be highly reliable, growth variability among individuals can deeply influence the anatomical changes from childhood to adulthood. A multi-disciplinary approach that considers many different biomarkers could help make radiological age determination more reliable when it is used to predict CA.     

Age estimation among Brazilians: Younger or older than 18?

The age estimation of living or dead individuals is an important part of forensic science because it can be used in various situations, including mass disasters, or for civil or criminal reasons, such as adoption or asylum. Teeth play a major role in this context because they are more resistant than bones in extreme environmental conditions and their development is hardly affected by exogenous or endogenous factors. Because the third molars (3rdM) are still in development from the age of 14, they are useful for determining whether an individual has reached the legal age of 18 years. This study aims to verify the method of Cameriere et al. (2008) in Brazil to discriminate whether an individual is under or over 18 years from the maturity index of the 3rdM (I3m). The analysis of 444 panoramic radiographs resulted in a sensitivity of 78.3%, a specificity of 85.1% and a correct classification of 87%. Significant differences in sexual dimorphism in the early mineralization of males were found only for the average age with I3m ≥ 0.08, except for the range (0.7, 0.9). Due to the high miscegenation ratio of the Brazilian population the ancestry was not one of the studied variables. The method is suitable for estimating adulthood for forensic purposes in Brazil, although it must be applied carefully and judiciously. We recommend a combination of several methods that are available to increase accuracy as well as the establishment of different parameters that are likely to determine whether a person is more or less than 18 years of age, depending on the different legal requirements, whether civil or criminal.     

牙种植体挤压植人后早期界面骨骨密度的X线影像分析

目的观察牙种植体挤压植入后界面骨的骨密度变化。方法在小型猪双侧前磨牙区挤压植入CompressR种植体(IGZ)。拍摄种植体/骨的数码X线根尖片影像。垂直于种植体长轴提取分析平面,统计分析基础骨密度分别与挤压后的骨密度和骨密度变化区域的相关性。结果挤压后的骨密度增加,基础骨密度与挤压后骨密度的相关系数r=0.8,P=0.00,与骨密度变化区域的相关系数r=-0.49,P=0.00;在同一分析平面种植体两侧的骨组织配对,基础骨密度与骨密度变化区域负相关占79.2%。结论骨挤压增加种植体界面骨的密度,提高初期稳定性。手术前的骨密度分析有助于种植方案的制定,植入前的基础骨密度影响种植体的稳定性;相同挤压距离下基础骨密度越大初期稳定性越好,但疏松骨质较密质骨能耐受更大的挤压距离。     

Demirjian’s stages and Cameriere’s third molar maturity index to estimate legal adult age in Peruvian population

ObjectiveTo compare the accuracy of Demirjian’s stages (DS) and Cameriere’s third molar maturity index cut-off value (I_3M < 0.08) to estimate the age of majority on panoramic radiographs (OPTs) from the dental clinic of the Scientific University of the South (UCSUR), Lima, Peru.MethodsAn observational cross-sectional study was conducted on the sample of 208 digital panoramic radiographs of patients aged 14–22 years examined during 2015 in UCSUR. The left lower third molars were analyzed using Adobe Photoshop® CS6. An effectiveness of specific DS and I_3M < 0.08 was evaluated by using accurate classification, sensitivity, specificity, positive (LR+) and negative (LR−) likelihood ratios and Bayes post-test probability (p).ResultsOnly G and H stages were practical for classify adults and minors in the tested sample, while I_3M < 0.08 showed the best performance in both sexes. For I_3M < 0.08, the accurate classification, sensitivity and specificity were 0.96, 0.96, 0.96 and 0.90, 0.84 and 0.95 in males and females, respectively. Values of LR+, LR− and p were 24.96, 0.04, 0.97 and 15.68, 0.17, 0.95 in males and females, respectively.ConclusionThe specific cut-off value of third molar maturity index (I_3M < 0.08) showed to be more accurate in discriminating adults and minors in Peruvian sample when a test with high sensitivity and specificity is required.     

Above or below 14 years? An orthopantomographic study based on chronological course of eruption of mandibular premolars and second molars in a sample of south Indian children

In the context of dental age assessment, two significant factors can be studied; tooth mineralisation and tooth emergence. Little is known about the role of a second molar eruption in forensic age estimation. This paper aims to contribute to forensic age estimation using an age threshold of 14 years, studying the eruption stages of permanent mandibular premolars and second molars. Totally 640 orthopantomograms (OPGs) of south Indian children, aged between 10 and 18 years, were evaluated using Olze et al. staging of tooth eruption stages (A–D). Spearman's rho correlation showed a strong, positive, and statistically significant correlation between the chronological age and the eruption stages of both sexes' teeth. Accuracy, sensitivity, specificity, likelihood ratios, and post-test probability values were calculated for all tested teeth. The best performance to discriminate individuals above or below 14 years showed stage D in second molars. The sensitivity varied between 89% and 94% and specificity between 75% and 84%, respectively. Receiver operating characteristic curve analysis revealed high diagnostic performance for stage D, with area under the ROC curve (AUC) values of 84% and 85% for tooth 37 and 85% and 83% for tooth 47 in males and females, respectively. In conclusion, it is possible to predict age over 14 years in south Indian children using tooth emergence stages from OPGs with a relatively high interobserver agreement and good diagnostic accuracy. However, there are some limitations and, therefore, must be used in conjunction with other methods.     

Diagnostic yield of ink-jet prints from digital radiographs for the assessment of approximal carious lesions: ROC-analysis

Aims

To investigate the diagnostic quality of different quality, individually calibrated ink-jet printers for the very challenging dental radiographic task of approximal carious lesion detection.

Materials and methods

A test-pattern evaluating resolution, contrast and homogeneity of the ink-jet prints was developed. 50 standardized dental radiographs each showing two neighbouring teeth in natural contact were printed on glossy paper with calibrated, randomly selected ink-jet printers (Canon S520 and iP4500, Epson Stylus Photo R2400). Printing size equalled the viewing size on a 17″ cathode-ray-tube monitor daily quality-tested according to German regulations. The true caries status was determined from serial sectioning and microscopic evaluation. 16 experienced observers evaluated the radiographs on a five-point confidence scale on all prints plus the viewing monitor with respect to the visibility of a carious lesion. A non-parametric Receiver-Operating Characteristics (ROC-) analysis was performed explicitly designed for the evaluation of readings stemming from identical samples but different modality. Significant differences are expressed by a critical ratio z exceeding ±2. Diagnostic accuracy was determined by the area (Az) underneath the ROC-curves.

Results

Average Az-values ranged between 0.62 (S520 and R2400) and 0.64 (monitor, iP4500), with no significant difference between modalities (P = 0.172). Neither significant (range mean z: −0.40 (S520) and −0.11 (iP4500)) nor clinically relevant differences were found between printers and viewing monitor.

Conclusions

Our results for a challenging task in dental radiography indicate that calibrated, off-the-shelf ink-jet printers are able to reproduce (dental) radiographs at quality levels sufficient for radiographic diagnosis in a typical dental working environment.     

Age estimation in dental pulp DNA based on human telomere shortening

Age estimation based on evidence found in teeth has received considerable attention within the field of forensic science. We determined the terminal restriction fragment (TRF) length, as telomere length, to estimate age. Using dental pulp DNA we found the average TRF length showed a tendency to shortening with aging. Our findings show that telomere shortening, based on dental pulp DNA is a new and useful approach to estimate age of the subject at the time of death.