Human dental age estimation combining third molar(s) development and tooth morphological age predictors

In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23?years, 25 gender-specific radiographs were collected within each age category of 1?year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by K?hler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals’ left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R ²) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6?% R2 increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15–23?year) should only be based on third molar development.     

Prediction of premolar tooth lengths based on their panoramic radiographic lengths

OBJECTIVE: Establishing a linear regression model for the determination of first premolar lengths based on panoramic radiographs. MATERIALS AND METHODS: The real lengths of 112 first premolars extracted for orthodontic reasons were measured and compared with their panoramic lengths. The teeth were divided into four groups according to their intraoral quadrant locations (T14, T24, T34, T44) and regression analysis was conducted for each group. RESULTS: A linear regression model for the prediction of tooth length (mm) based on the panoramic length was established (P < 0.0001): For group T14 the predicted length = (panoramic length x 0.698) + 2.61. For group T24 the predicted length = (panoramic length x 0.5056) + 7.844. For group T34 the predicted length = (panoramic length x 0.5075) + 9.282. For group T44 the predicted length = (panoramic length x 0.436) + 11.298. CONCLUSION: Prediction of all first premolar lengths using their panoramic images is both feasible and reliable.     

Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults

Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15–23?years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22?years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars’ eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.     

Development of formulae for dental age estimation using digital radiographs in the Mongolian population

This study aimed to examine the applicability of the pulp/tooth ratio (PTR) method for age estimation in Mongolian populations using panoramic radiographs and derive new regression formulae. Moreover, we aimed to assess the accuracy of these formulae in other subjects from the Mongolian population and compare them with the other formulae derived from different Asian populations.The total sample size of the study was 381. The formulae were derived from the examination of panoramic radiographs of 271 individuals aged 15–62 years. Following Cameriere’s method, PTR was calculated for the upper and lower canine teeth. Linear regression analyses were performed between the actual age and that obtained from upper-lower canine PTR and established formulae for age estimation. To verify the formulae, two types of test samples were collected: 73 panoramic radiographs and 37 periapical radiographs. The estimated age was calculated using our new formulae and three other formulae derived from Asian populations.The correlation coefficient between the actual age and that obtained by PTR was significantly negative for both canines. According to our new regression formulae, the differences between the estimated age and actual age showed a bell-shaped curve distribution in both test groups. While using the other formulae derived from the Asian population, the distribution patterns obtained were significantly different in the Mongolian population.This study was the first to examine the relationship between actual age and PTR in Mongolian population, and these results advance the field of forensic science in Mongolia.     

Pre-operative radiographic evaluation of lower third molars with computed tomography

OBJECTIVES: To report radiographic findings of examinations with computed tomography (CT) of impacted lower third molars with an intimate relation to the mandibular canal and to investigate how findings of a dark band across the roots of the lower third molar on panoramic views correspond to the CT findings. METHODS: CT images of 90 lower third molars (64 patients, mean age 34.6 years) in which plain radiography was insufficient to allow determination of the precise anatomical relations were reviewed retrospectively. Panoramic views of 88 teeth existed; these images were interpreted independent of the CT examinations with respect to presence of a dark band across the roots. RESULTS: In 31% of the CT images, the course of the mandibular canal was buccal, in 33% lingual, in 26% inferior, and in 10% inter-radicular. The tooth was in contact with the mandibular canal in 94% and with the lingual cortex in 86%. In 23%, grooving of the root by the canal was judged to be present. In 63% of the cases where a dark band across the roots was observed on panoramic radiographs, CT revealed grooving of the root. CONCLUSIONS: Pre-operative CT of lower third molars is motivated in selected cases when plain radiography is inconclusive. The finding of a dark band across the roots on panoramic radiographs is an indicator of grooving of the tooth by the canal and justifies a pre-operative CT examination. The absence of dark bands on panoramic views does not exclude grooving of the roots.     

The differences in panoramic mandibular indices and fractal dimension between patients with and without spinal osteoporosis

OBJECTIVES: The aims of this study were to evaluate the relationship between osteoporosis, oral signs, body mass index and age; and to assess the possibility of using these parameters as an indicator of post-menopausal osteoporosis. The oral signs were panoramic-based mandibular indices, such as cortical width, cortical index, panoramic mandibular index and mandibular crest resorption degree; the number of teeth and fractal dimension analysis. METHODS: Forty-eight post-menopausal women between the ages of 40 years and 64 years were evaluated. Mandibular indices and the number of mandibular teeth were measured and evaluated from panoramic radiographs and fractal dimension was calculated from the direct digital periapical radiographs of the mandibular premolar-molar region in box-counting method. Weight, height, menopausal status and age of the patients were recorded by questionnaire. Bone mineral densities of the patients were measured with dual energy X-ray absorptiometry. RESULTS: In this study there were no statistically significant differences between the osteoporotic and non-osteoporotic patients for cortical width, panoramic mandibular index, alveolar crest resorption degree, fractal dimension and the number of mandibular teeth, but there was a difference for cortical index. Binary logistic regression analyses demonstrated that age (P = 0.015) was an important risk factor for osteoporosis. CONCLUSION: The results of this study demonstrated that osteoporotic patients were more likely to have altered inferior cortex morphology than non-osteoporotic patients and age is an important risk factor for osteoporosis.     

Quantification of secondary dentine formation from orthopantomograms—a contribution to forensic age estimation methods in adults

The accuracy of most age determination methods in adults is unsatisfactory and therefore more precise methods are required. Teeth provide several useful points about an individuals age. With advancing age secondary dentine is deposited along the wall of the dental pulp chamber leading to a reduction in the size of the pulp cavity. These age-related changes can be determined and measured from dental radiographs. The aim of this study was to explore if measurements of the size of the pulp cavity performed on orthopantomograms can be used for individual age estimation. Measurements were made digitally for 6 types of teeth from orthopantomograms of 168 individuals aged between 14 and 81 years old. To compensate for errors due to the technique of radiography—for instance differences in angulation—ratios of distances were calculated: pulp/root length, pulp/tooth length and pulp/root width at three different root levels. The width ratios of the pulp cavity showed significant correlation to the chronological age and the coefficient of determination (r²) was highest in the upper lateral incisors (r²=0.913) when an exponential or a logistic regression model was constructed. At the same distance with a linear regression model the coefficient of determination (r²) reached 0.839.     

A comparison of the diagnostic utility of two image receptors for panoramic radiography

OBJECTIVE: To compare the diagnostic utility of two screen-film systems for panoramic radiography, one based on green and the other on ultraviolet light. MATERIALS AND METHODS: Two hundred consecutive adult patients with teeth in all four quadrants requiring panoramic radiographs were randomly allocated to one of two groups. One group was imaged with OGA L (CEA AB, Str?ngn?s, Sweden) film using Lanex Regular (Eastman Kodak, Rochester, NY, USA) screens (the Lanex group). The other group was imaged using Ultra-Vision (Dupont UK Limited, Hertfordshire, UK) film and screens (the Ultra-vision group). Two different panoramic machines were used, a Planmeca (Planmeca OY, Helsinki, Finland) and Cranex (Soredex Orion Corporation, Helsinki, Finland). The radiographs were evaluated by two radiographers for overall quality and any faults recorded. Two dental radiologists evaluated the crestal and apical areas of every standing tooth on a 4-point scale. The likelihood of getting a high-quality image with the different films was modelled using logistic regression, adjusting for the radiologist and the area of the tooth being examined. Inter- and intra-examiner agreement was calculated using Kappa and weighted Kappa where appropriate. RESULTS: The radiographers recorded no significant differences in positioning errors between the two groups of film. However, the films produced on the Cranex were less likely to be recorded as excellent. The radiologists' interexaminer agreement for the lower molars and upper incisors was only moderate at best (kappa = 0.56). No significant differences were found between the likelihood of the two types of film providing a high-quality image. Crestal areas were more likely to be scored well than apical areas. CONCLUSION: There were no differences in ease of discerning apical and crestal areas between the two screen-film systems. There was only poor to moderate agreement between the two radiologists. Ultra-Vision can be recommended as an alternative to existing rare earth systems for panoramic radiography.     

Age estimation from structural changes of teeth and buccal alveolar bone level

Forensic odontology plays a vital role in the identification and age estimation of unknown deceased individuals. The purpose of this study is to estimate the chronological age from Cone-Beam Computed Tomography (CBCT) images by measuring the buccal alveolar bone level (ABL) to the cemento-enamel junction and to investigate the possibility of employing the age-related structural changes of teeth as studied by Gustafson. In addition, this study will determine the forensic reliability of employing CBCT images as a technique for dental age estimation. A total of 284 CBCT images of Malays and Chinese patients (150 females and 134 males), aged from 20 years and above were selected, measured and stages of age-related changes were recorded using the i-CAT Vision software. Lower first premolars of both left and right side of the jaw were chosen and the characteristics described by Gustafson, namely attrition, secondary dentine formation and periodontal recession were evaluated. Linear regression analysis was performed for the buccal bone level and the R values obtained were 0.85 and 0.82 for left and right side respectively. Gustafson's characteristics were analysed using multiple regression analysis with chronological age as the dependent variable. The results of the analysis showed R values ranged from 0.44 to 0.62. Therefore it can be safely concluded that the buccal bone level highly correlated with the chronological age and is consequently the most suitable age-related characteristic for forensic age estimation.     

Dental radiographic information of term newborn babies within the first month: Analyzing five radiographic cases along with physical attributes in Japan

BackgroundAlthough dental radiography is a valuable tool for age estimation in forensic anthropology and odontology, very limited radiological data are available regarding tooth development in healthy newborn babies during the first month of life.AimThis study aimed to describe the radiological findings of tooth development in babies aged 0 days to 1 month.DesignWe analyzed the postmortem findings of five newborn babies with no known natural cause of death who had undergone autopsy, computed tomography (CT), and dental radiography. We estimated the gestational age for the babies aged 0 days and analyzed the condition of mandibular symphysis, existence of tooth germs, and presence or absence of calcification of the first permanent molars of all the babies.ResultsThe calcified form of 20 deciduous teeth, tooth germs of the permanent upper and lower first molars, and non-calcified mandibular symphysis were observed in each case. However, calcification of the first permanent molar was observed in only two 1-month-old babies.ConclusionThe dental radiographic findings and anthropometric measurements of non-skeletonized, non-mummified term babies confirmed calcification of all the deciduous teeth and the first permanent molar at the age of 0 days and 1 month, respectively.     

Relationship between bone mineral density and tooth loss in elderly Japanese women.

OBJECTIVE: To evaluate the relationship between vertebral bone mass and tooth loss and jaw bone mass in elderly Japanese women. METHODS: Mandibular cortical bone mass, alveolar bone height and number of teeth present (total, anterior, and posterior) were compared with the 3rd lumbar vertebral bone mineral density (L3BMD), measured by dual energy computed tomography (DEQCT), in 90 Japanese women by means of multiple regression analysis, controlling for body mass index, menopausal status, years since menopause and self-reported periodontal condition. RESULTS: Mandibular cortical bone mass and number of posterior teeth were associated with both alveolar bone height and L3BMD, but there was no association between alveolar bone height, number of anterior teeth present and L3BMD. CONCLUSION: Our results suggest that the loss of posterior teeth may be associated with a decrease not only in alveolar bone height, but also alveolar bone mineral density (BMD). The latter may be related to a decrease of lumbar vertebral BMD.     

Sex estimation based on tooth measurements using panoramic radiographs

Background

Sex determination is an important step in establishing the biological profile of unidentified human remains.

Aim

The aims of the study were, firstly, to assess the degree of sexual dimorphism in permanent teeth, based on digital tooth measurements performed on panoramic radiographs. Secondly, to identify sex-related tooth position-specific measurements or combinations of such measurements, and to assess their applicability for potential sex determination.

Materials and methods

Two hundred digital panoramic radiographs (100 males, 100 females; age range 22–34 years) were retrospectively collected from the dental clinic files of the Dentomaxillofacial Radiology Center of the University Hospitals Leuven, Belgium, and imported in image enhancement software. Tooth length- and width-related variables were measured on all teeth in upper and lower left quadrant, and ratios of variables were calculated. Univariate and multivariate analyses were performed to quantify the sex discriminative value of the tooth position-specific variables and their combinations.

Results

The mandibular and maxillary canine showed the greatest sexual dimorphism, and tooth length variables had the highest discriminative potential. Compared to single variables, combining variables or ratios of variables did not improve substantially the discrimination between males and females.

Discussions and conclusions

Considering that the discriminative ability values (area under the curve (AUC)) were not higher than 0.80, it is not advocated to use the currently studied dental variables for accurate sex estimation in forensic practice.

     

Measurements of tooth length in panoramic radiographs. 1. The use of indicators.

The aim of this study was to investigate both the actual and the radiographic tooth lengths of the maxillary first molar and second premolar and the mandibular premolars in panoramic radiographs. The actual length of 64 extracted teeth was measured. Steel balls were then attached to the cusp and apex and the teeth embedded in plastic moulds. Each pair of plaster casts with their set of teeth was radiographed with an Orthopantomograph twice at an interval of 1 month. The actual and the radiographic tooth length was measured twice by one observer. The mean tooth length of the molar was shorter than that of the premolars. The mean difference between the repeated measurements of the actual tooth length was small and ranged between 0.47 and 1.16% of the tooth length. The mean difference between repeated measurements of the radiographic tooth length was also small, with a method error of 0.13-0.21 mm. The vertical magnification in panoramic radiography was lower for mandibular premolars (13-15%) than for the maxillary second premolar and first molar (17-28%). The palatal root of the maxillary first molar had the highest vertical magnification (28%). Following the second set of radiographs, the mean difference between the measurements was small, except for the palatal root of the maxillary first molar (P < 0.001). Radiographic measurements of this root should therefore be used with caution. The results for the other roots examined indicate that these could be measured with high reproducibility.     

数字曲面体层X片在评价非负荷期种植体周围骨吸收的临床应用

目的:评价数字曲面体层X片在测量非负荷期种植体周围牙槽骨吸收的应用情况。方法:观测、分析对比26例患者50枚Camlog系统种植体临床应用非负荷期间数字化曲面体层X片和X线牙片上种植体周围牙槽骨吸收的情况。结果:50枚Camlog种植体植入后10 d,两种X片骨吸收测量结果分别为0.65 mm、0.81 mm,两者之间无明显差异;第4个月(或6月\下颌)分别为0.12 mm、0.19 mm,两者之间无明显差异。结论:本研究显示数字化曲面体层X片在测量非负荷期种植体周围牙槽骨吸收的应用中有操作简单、重复性好、精确度高、变形可补偿等优点,有实际应用价值,值得推广。     

中国老年人群牙齿缺失与全因死亡风险关联的前瞻性队列研究

 目的 探讨中国老年人群余留牙齿数量与全因死亡的关联。方法 基于2011－2018年中国老年健康影响因素跟踪调查(CLHLS)纵向随访资料,通过调查问卷获取调查对象的基线特征、既往病史、余留牙齿数量等信息,采用Katz量表和简易智能状态检查量表评估日常活动能力和认知功能。采用多因素Cox等比例风险模型评估余留牙齿数量与全因死亡的关联。结果 共纳入8658例老年人,男3895例(45.0%),女4763例(55.0%),平均年龄为(85.7±11.2)岁,经7年随访,死亡4488例(51.8%),牙齿余留数量与年龄增长呈负相关(P<0.05)。多因素Cox回归结果显示,在调整年龄、性别、身体质量指数(body mass index,BMI)、吸烟、饮酒、锻炼、高血压、呼吸道疾病、心血管疾病、日常活动能力失能、认知功能受损等因素后,余留牙齿数量每增加一个,全因死亡风险下降1%,与余留牙齿数量为0的老年人相比,≥20颗余留牙齿的老年人的全因死亡风险下降22%。结论 中国老年人群余留牙齿数量的减少可能增加全因死亡风险,应预防老年人群牙齿脱落。     

Dental age estimation from the developmental stage of the third molars in Iranian population

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. The aim of this study was to achieve a referral database and regression equations for dental age estimation of unaccompanied minors of Iran nationality. A total of 1200 orthopantomograms were collected from original Iran and equally divided in age categories between 10 and 27 years. On the radiographs, the developmental stage of the third molars was scored applying a Demirjian et al. scoring technique. Inter- and intra-observer reliabilities were tested using kappa statistics. Correlation between the scores of all four wisdom maxillary and mandibular third molars teeth and left/right symmetry were evaluated with spearman correlation coefficient. Student’s t-test on asymmetry was performed and regression formulas were calculated. The present database was the first to assemble third molar developmental scores on radiographs of Iran individuals and provided more appropriate dental age estimation of unaccompanied Iran minors. To enhance the accuracy of forensic age estimates based on third molars mineralization, the use of population-specific standards is recommended.     

Evaluation of volumetric changes of teeth in a Brazilian population by using cone beam computed tomography

The purpose of this study was to test the usefulness of some morphometric parameters of the teeth in 5 different age groups through images of Cone Beam CT. 118 upper central incisors clinically acquired of 60 women and 58 men aged between 22 and 70 years were selected. The hard tissue volume and the pulp cavity volume of each tooth was obtained and computed by the software DentalSlice^® and the measures were assessed (pulp cavity volume, hard tissue volume, tooth volume and pulp cavity/tooth volume ratio). The pulp cavity volume and the pulp cavity/tooth volume ratio showed significant differences between age groups (p < 0.001). Linear regression analysis showed a coefficient of determination of 0.21 which suggests that there is a weak correlation between the pulp cavity/tooth volume ratio and age.     

Dental age estimation in Malaysian adults based on volumetric analysis of pulp/tooth ratio using CBCT data

Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher’s Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.     

Observer performance in the assessment of periapical pathology: a comparison of panoramic with periapical radiography.

Observer performance in the assessment of the periapical pathology from panoramic and periapical radiography was examined. Five endodontists, five general practitioners and five oral radiologists were asked to assess the periapical status of 117 teeth. The observers assessed the panoramic and periapical radiographs of the teeth, which were evenly distributed throughout the jaws with a 50% probability that either an osteolytic or sclerotic lesion was present. The results of the comparison between panoramic and periapical radiography were influenced by the selection of observers. When the oral radiologists acted as observers, the mean P(A) value for periapical radiography was higher than for panoramic radiography (P less than 0.001), resulting in periapical radiography presenting a higher overall diagnostic accuracy than panoramic radiography for all 15 observers (P less than 0.01). There was, however, no difference between panoramic and periapical radiography when the two groups of endodontists and general practitioners acted as observers. The comparison of the three groups of observers showed no difference between their diagnostic accuracy when assessing panoramic radiographs. With periapical radiography, the oral radiologists demonstrated a higher diagnostic accuracy than the endodontists (P less than 0.05). The observers in each group with the highest diagnostic accuracy also had the highest intra-observer agreement. The mean intra-observer agreement of the five general practitioners was higher than those of the other two groups of observers for panoramic radiography. For periapical radiography, the mean agreement rates of the groups were comparable.