Application of Kvaal et al.’s age estimation method to panoramic radiographs from Turkish individuals

Comparative evaluation of two different dental age estimation methods using tooth pulp: A CBCT study

AIM

To estimate the age of an individual based on 3D radiographic evaluation of pulp width of maxillary central incisor.

MATERIALS AND METHODS

This study included 185 CBCT images of individuals within age range of 14-64 years. Images were evaluated for maxillary central incisors and pulp width measurements were taken from cementoenamel junction and middle third of root. Obtained data was subjected to correlation and regression analysis from which the age of an individual was predicted. Results of the present study were compared with another study by the same authors.

RESULTS

A negative linear relationship was obtained between age and pulp width. The standard error of estimate (SEE) in sagittal section was 11.36 years and that in coronal section was 11.23 years. The coefficient of determination for sagittal section was 0.107 and for coronal section was 0.127. An obtained regression formula was highly significant. Division of samples into various age groups reduced SEE drastically.

CONCLUSION

It can be concluded that pulp width of maxillary central incisor is a reliable indicator of age estimation.

Dental age estimation using the Kvaal method-an evaluation of length and width ratios: a systematic review

This study aimed to systematically review the correlational accuracy between width ratios and length ratios based on the Kvaal methodology with chronological age. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search strategy included ProQuest, PubMed, Science Direct, and Taylor and Francis and Willey online without time or language restriction using Kvaal method of age estimation as key words for the search up to December 2021. A team of two researchers independently selected the studies and extracted the data. The Covidence platform was used to systematically organize all titles. The full texts of eligible studies were analyzed. Risk of bias (RoB) was assessed using a modified (to the specific characteristics of this systematic review) checklist based on Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement checklist for observational studies. A total of 658 articles were initially reviewed, but 22 were selected for inclusion. The risk of bias was estimated to be unclear to low overall. Among the length ratios, ratio R showed a strong association with chronological age, followed by ratio P. For the width ratios, ratio B demonstrated a close association with chronological age, followed by ratio C. The results suggest that width ratios correlate better with chronological age than length ratios. This systematic review suggests the width ratios are more strongly associated with chronological age than the length ratios. Using a width ratio could serve as a convenient and rapid way to estimate dental age. Our results apply equally to all types of ethnic groups.

Application of the Kvaal method to CBCT reconstructed panoramic images for age estimation

As the teeth are more durable than other parts of the skeleton, they provide valuable data for age estimation. Age estimation from adult teeth is mainly based on secondary dentin production. The present study aimed to devise a regression formula for age estimation specific to the Anatolian population using the Kvaal method on CBCT reconstructed panoramic images. In total, 201 individuals aged between 20 and 69 were divided into two groups: data from the study group (n = 101) were used to create the regression formulae, and data from the control group (n = 100) were used to test the formulae. Pearson's correlation coefficients and linear regression analyses were performed. Maxillary teeth provided more accurate age estimates than mandibular teeth. The regression formulae derived in this study are found to be statistically applicable and reasonably accurate. However, these results should be interpreted with caution.

Machine learning assessment of dental age classification based on cone-beam CT images: a different approach

OBJECTIVES

Machine learning (ML) algorithms are a portion of artificial intelligence that may be used to create more accurate algorithmic procedures for estimating an individual's dental age or defining an age classification. This study aims to use ML algorithms to evaluate the efficacy of pulp/tooth area ratio (PTR) in cone-beam CT (CBCT) images to predict dental age classification in adults.

METHODS

CBCT images of 236 Turkish individuals (121 males and 115 females) from 18 to 70 years of age were included. PTRs were calculated for six teeth in each individual, and a total of 1416 PTRs encompassed the study dataset. Support vector machine, classification and regression tree, and random forest (RF) models for dental age classification were employed. The accuracy of these techniques was compared. To facilitate this evaluation process, the available data were partitioned into training and test datasets, maintaining a proportion of 70% for training and 30% for testing across the spectrum of ML algorithms employed. The correct classification performances of the trained models were evaluated.

RESULTS

The models' performances were found to be low. The models' highest accuracy and confidence intervals were found to belong to the RF algorithm.

CONCLUSIONS

According to our results, models were found to be low in performance but were considered as a different approach. We suggest examining the different parameters derived from different measuring techniques in the data obtained from CBCT images in order to develop ML algorithms for age classification in forensic situations.

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.

Combining the third molar mineralization to further improve the accuracy of the Kvaal's method in dental age estimation of subadults in northern China

The morphological changes based on deposition of secondary dentin and mineralization of the third molar have been proven to be related to chronological age. However, Kvaal's method on the theory of deposition of secondary dentin was controversial with respect to dental age estimation in the recent research. The aim of this study was to combine the parameters of Kvaal's method with relatively high correlation coefficients and mineralization stages of the third molar to improve the accuracy of predicting the dental age of subadults in northern China. A total of 340 digital orthopantomograms of subadults aged from 15 to 21 years were analysed. A training group was used to test the accuracy of the original Kvaal's method and to establish novel methods for subadults in northern China. A testing group was used to compare the accuracy of the newly established methods with the Kvaal's original method and with published method specifically used in northern China. To increase the feasibility of our estimation model, we combined the mineralization of the third molar to build a combined specific formula. The results showed that the combined specific model increased the coefficient of determination to 0.513, and the standard error of the estimate was reduced to 1.482 years. We concluded that the combined specific model based on the deposition of secondary dentin and mineralization of the third molar could improve the accuracy of dental age assessment of subadults in northern China.

KEY POINTS

The decrease in the dental pulp cavity based on deposition of secondary dentin is a useful variable for assessing age.A total of 340 orthopantomographs were used in this research, including 278 in training groups and 62 in testing groups.Original Kvaal's method underestimated the dental age for subadults in northern China.The equation of combined specific method constructed in our study was proved more suitable to calculate dental age for subadults in northern China.

Age Estimation Using Maxillary Central Incisor Analysis on Cone Beam Computed Tomography Human Images

Forensic dentistry plays an important role in human identification, and dental age estimation is an important part of the process. Secondary dentin deposition throughout an individual's lifetime and consequent modification in teeth anatomy is an important parameter for age estimation procedures. The aim of the present study was to develop regression equations to determine age in adults by means of linear measurements and ratios on sagittal, coronal and axial slices of maxillary central incisors using cone bean computed tomography (CBCT). Multiplanar measurements of upper central incisors were taken for a sample of 373 CBCTs. Subsequently, one-way analysis of variance (ANOVA) and multivariate linear regressions were performed for age estimation. The equations obtained from axial linear measurements and ratios presented a standard error of the estimate (SEE) of ±10.9 years (R² = 0.49), and a SEE of ±10.8 years (R² = 0.50), respectively. The equation obtained for multiplanar linear measurements presented a SEE of ±10.9 years (R² = 0.52), while the equation for multiplanar ratios presented a SEE of ±10.7 years (R² = 0.51). Thus, CBCT measurements on upper central incisors were found to be an acceptable method for age estimation. Horizontal measurements, especially pulp measurements, improve the accuracy of age estimate equations.

Application of the Kvaal Method in Age Estimation of the Serbian Population Based on Dental Radiographs

This study aimed to evaluate the applicability of the Kvaal method in determining the age of a Serbian population. In this retrospective descriptive study, 170 dental patients (age range 16–77 years) were included. The measurements of six types of teeth were performed on digital orthopantomography radiographs according to the Kvaal method. Statistical inter-observer and intra-observer reliabilities were calculated to evaluate the reproducibility of the measurements, as well as to examine the correlation between chronological age and measured values. The evaluation revealed a substantial difference (over 12 years) between chronological and estimated age. The P ratio had the strongest correlation with chronological age for the maxillary central (r = ±0.293) and lateral incisors (r = ±0.240), whereas the pulp/root width ratio at level A had the strongest correlation for the mandibular first premolars (r = ±0.270). The lowest SD values, for measurements on teeth 15/25 (SD = 125,787), had the most accurate correlation with age. Thus, we can conclude that the original Kvaal method is not applicable in the age estimation of the Serbian population. For future research, we suggest using cone beam computer tomography as a precise technology to evaluate the applicability of Kvaal and other methods for age estimation.

A retrospective institutional study of human age determination by evaluating the pulp length and width ratio of the maxillary lateral incisor on panoramic radiographs in Indonesian subjects

Purpose

The pulp length to width (PL/W) ratio of the maxillary lateral incisor can be used as an age determination method. This study aimed to investigate the correlation between the PL/W ratio of the maxillary lateral incisor on panoramic radiographs and human chronological age in Indonesian subjects.

Materials and Methods

This study analyzed with 134 maxillary lateral incisors on 113 panoramic radiographs from patients who visited the Oral and Maxillofacial Radiology Unit of Dental Hospital Universitas Padjadjaran, Bandung, Jawa Barat, Indonesia, from 2013 to 2018 (age range: between 11 to 60 years). The pulp length was measured from the pulp chamber roof to the apical foramen, and the pulp width was measured on the cervical area of the cementoenamel junction in millimeters using Fiji ImageJ open-source software. Simple linear regression (in SPSS) was used to analyze the results. The reliability of the observers was evaluated.

Results

The PL/W ratio of the maxillary lateral incisor was significantly correlated with chronological age (P<0.01). No statistically significant difference was found in the PL/W ratio between the left and right maxillary lateral incisors (P=0.333). There was a very strong correlation (r=0.939) between the PL/W ratio of the maxillary lateral incisor and human chronological age, with the following formula: age= -3.057+1.875×PL/W ratio (R²=0.882, standard error of estimate: 4.659).

Conclusion

The PL/W ratio of the maxillary lateral incisor on panoramic radiograph can be used for age determination in Indonesian subjects.

Development of an automatic multiplanar reconstruction processing method for head computed tomography

BACKGROUND

Head computed tomography (CT) is a commonly used imaging modality in radiology facilities. Since multiplanar reconstruction (MPR) processing can produce different results depending on the medical staff in charge, there is a possibility that the antemortem and postmortem images of the same person could be assessed and identified differently.

OBJECTIVE

To propose and test a new automatic MPR method in order to address and overcome this limitation.

METHODS

Head CT images of 108 cases are used. We employ the standardized transformation of statistical parametric mapping 8. The affine transformation parameters are obtained by standardizing the captured CT images. Automatic MPR processing is performed by using this parameter. The sphenoidal sinus of the orbitomeatal cross section of the automatic MPR processing of this study and the conventional manual MPR processing are cropped with a matrix size of 128×128, and the value of zero mean normalized correlation coefficient is calculated.

RESULTS

The computed zero mean normalized cross-correlation coefficient (Rzncc) of≥0.9, 0.8≤Rzncc < 0.9 and 0.7≤Rzncc < 0.8 are achieved in 105 cases (97.2%), 2 cases (1.9%), and 1 case (0.9%), respectively. The average Rzncc was 0.96±0.03.

CONCLUSION

Using the proposed new method in this study, MPR processing with guaranteed accuracy is efficiently achieved.

The impact of age mimicry bias on the accuracy of methods for age estimation based on Kvaal's pulp/tooth ratios: a bootstrap study

INTRODUCTION

Methods based on pulp/tooth ratios proposed by Kvaal et al. (1995) have been widely used for age estimation in adults. The tendency of age estimates to mimic the age structure of the reference population, i.e. age mimicry bias, is a possible source of controversy in the results of studies. The primary objective of the present study was to evaluate the effect of age mimicry bias on the accuracy of the original Kvaal's method and its recent modification proposed by Roh et al. (2018).

METHOD AND MATERIAL

The study sample comprised 240 cone-beam computed tomography scans of an Iranian population. The bootstrap procedure was used to study the impact of age mimicry bias on age estimates by constructing reference populations with different age structures. The accuracy of Kvaal's and Roh's variables for age estimation was assessed using a twofold cross-validation technique and principal component analysis.

RESULTS

The application of original equations resulted in SEE values highly greater than the acceptable threshold for forensic purposes (10 years). The population-specific equations obtained SEE values of 9.18, 11.03, and 9.22 years using Kvaal's variables and 9.19, 11.13, and 9.14 years using Roh's variable for the maxillary, mandibular, and all teeth, respectively. The bootstrap procedure revealed that using uneven reference populations to formulate the equation resulted in significantly greater SEEs (almost all >10 years) that were not acceptable for forensic purposes. Moreover, using an older (a younger) reference population contributed to a sharp rise in the amount of over- (under-) estimation for younger (older) age groups.

CONCLUSION

Age mimicry bias had an undesirable impact on the accuracy of dental age estimation based on Kvaal's and Roh's methods. The accuracy of the original equations was low for age estimation in the Iranian sample. However, the performance of the population-specific equations was reasonably acceptable for the maxillary and all six teeth.

Age estimation in the living: A scoping review of population data for skeletal and dental methods

Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues. This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living. Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries. For most of the western and central African countries there are currently no data on the rate of skeletal and dental maturation. The same applies to the countries of the Middle East, as well as the eastern European countries, especially as regard the skeletal development.

Age estimation in Brazilian adults by Kvaal's and Cameriere's methods

The aim of this study was to verify the precision and applicability of two methods of age estimation, Kvaal's and Cameriere's methods, among Brazilian adults. A sample composed of periapical radiographs of canine teeth belonging to 320 Brazilian adults was analyzed, divided into groups according to sex (male and female) and age group (20-29 years, 30-39 years, 40-49 years and 50-59 years). Kvaal's method presented better results when compared to the results of Cameriere's method in the general evaluation of each canine tooth, except for the upper left canine (tooth 23), which presented a mean error (ME) with no statistically significant difference between the methods (Kvaal: ME = 7.43, p = 0.4991, Cameriere: ME = 7.55, p = 0.6982). In the evaluation by age groups, Kvaal's method presented a lower variation between the real age and estimated age when applied to the age groups of 20-29 years and 30-39 years compared to the results provided by Cameriere's method. With respect to the groups aged 40 to 49 years and 50 to 59 years, Cameriere's method presented better performance than the results provided by Kvaal's method. The methods of estimating age proposed by Kvaal and Cameriere are simple and nondestructive and have demonstrated reproducibility and reliability. The Kvaal method was more accurate for the age groups of 20-29 and 30-39 years, and for those over 40 years, the Cameriere method was the most accurate.

Can canines alone be used for age estimation in Chinese individuals when applying the Kvaal method?

Due to the secondary dentin formation, the dental pulp undergoes changes in shape throughout life. Based on this phenomenon, the Kvaal method has been applied to various populations for age estimation, and its usefulness has been verified. When applying the Kvaal method to Chinese subjects, we observed a relatively strong correlation between mandibular canines and age. This study notes the correlation between canines and chronological age and is the first to identify which canine is most closely related to chronological age. In addition, a new, simpler formula is determined based on canines according to Kvaal's methodology. The radiographs of 360 individuals from northern China were selected, from which the widths and lengths of the pulp from four canines were measured according to the Kvaal method. Next, inter- and intra-observer reliabilities were analyzed in order to assess the repeatability of these measurements. The correlation between measurements and age was examined, and Chinese-specific age estimation formulae were derived. The results revealed that the ratios from the left maxillary canine exhibited the strongest correlation with age compared to the other canines, whereas the left mandibular canine showed the weakest correlation, which may contribute to the overall poor correlation of mandibular canines with age. What's more, the formula derived from the left maxillary canine in this study displayed the highest coefficients of determination, and the formula derived from all canines showed the lowest residuals. Both of these formulae performed better than the Chinese-specific formula derived from six different types of teeth in our previous study, which had formerly possessed the highest coefficients of determination and the lowest residuals. Thus, we concluded that canines do play an important role in age estimation in the Chinese population, and the correlation between maxillary canines and chronological age is stronger than that of mandibular canines, although no distinct trend as to which side is better correlated with age was established. Going forward, we recommend the analysis of additional samples from different geographical regions and populations to further verify the importance of canines in age estimation.

Digitized Morphometric Analysis using Maxillary Canine and Mandibular First Molar for Age Estimation in South Indian Population

Background:

In recent years, the estimation of age in living individuals have become important to solve judicial or civil problems. Secondary dentin deposition occurs as the age advances and can be measured by calculating the reduction in pulp chamber through Noninvasive radiograph techniques.

Aim:

The aim is to derive precise population specific formulae for age estimation.

Materials and Methods:

Digitalized Orthopantomography of 150 subjects, was retrieved. The subjects were divided into study and test group. Pulp tooth area ratio was recorded from the maxillary canine and pulp chamber crown root trunk height ratio was recorded from a mandibular first molar.

Statistical Analysis:

Regression equation was derived from study group subjects and this equation was used to estimate the age of subjects in the test group.

Results:

No significant differences were seen between mean chronological age and mean estimated age (p-value- 0.157). Mean Absolute Error (MAE) was estimated to be 2.76 years. The percentage of estimated ages in test sample < ± MAE was 72%. The difference was higher in the group I and II (p-value- 0.001 and 0.002)

Conclusion:

The equation derived from the anterior and posterior teeth together gave more accurate results in the present study. The prediction accuracy can further be enhanced by using multiple teeth or by utilizing other linear measurements in the same teeth.

Applicability of Cameriere's and Drusini's age estimation methods to a sample of Turkish adults

OBJECTIVES

The aim of this study was to investigate the applicability of Drusini's and Cameriere's methods to a sample of Turkish people.

METHODS

Panoramic images of 200 individuals were allocated into two groups as study and test groups and examined by two observers. Tooth coronal indexes (TCI), which is the ratio between coronal pulp cavity height and crown height, were calculated in the mandibular first and second premolars and molars. Pulp/tooth area ratios (ARs) were calculated in the maxillary and mandibular canine teeth. Study group measurements were used to derive a regression model. Test group measurements were used to evaluate the accuracy of the regression model. Pearson's correlation coefficients and regression analysis were used.

RESULTS

The correlations between TCIs and age were -0.230, -0.301, -0.344 and -0.257 for mandibular first premolar, second premolar, first molar and second molar, respectively. Those for the maxillary canine (MX) and mandibular canine (MN) ARs were -0.716 and -0.514, respectively. The MX ARs were used to build the linear regression model that explained 51.2% of the total variation, with a standard error of 9.23 years. The mean error of the estimates in test group was 8 years and age of 64% of the individuals were estimated with an error of <±10 years which is acceptable in forensic age prediction.

CONCLUSIONS

The low correlation coefficients between age and TCI indicate that Drusini's method was not applicable to the estimation of age in a Turkish population. Using Cameriere's method, we derived a regression model.

Relationship between pulp-tooth volume ratios and chronological age in different anterior teeth on CBCT

Background

The CBCT imaging technique exhibits proper accuracy to determine the internal anatomy of teeth. Therefore, this technique can use to estimate age by measuring the amount of decrease in the volume of the pulpal cavity of teeth. The aim of the present study was to evaluate the correlation between chronological age and pulp-to-tooth volume ratios in anterior teeth with the use of the CBCT technique and to determine a regression model to estimate human age.

Material and Methods

In this present descriptive-analytical study, 122 subjects (46 males and 76 females), with an age range of 13-70 years, were evaluated. The MIMICS software program was used to determine the pulp-to-tooth volume ratios in 732 anterior teeth. Regression analysis was used to assess the correlation between age and pulp to tooth volume ratios.

Results

In all the teeth evaluated, there was an inverse and significant correlation between age and the pulp-to-tooth volume ratios in males and females, with a stronger correlation in males. In addition, such a correlation was stronger in maxillary central incisors and canines. In the model in which the mean of ratios in anterior teeth was used to estimate age the correlation was stronger compared to that in single tooth.

Conclusions

In general, the results of the present study showed that it is advisable to use the mean of all the ratios of anterior teeth in forensics to estimate age.

Key words:Age estimation , cone-beam CT, forensic dentistry, secondary dentin, pulp cavity.

Age estimation in adults by dental imaging assessment systematic review

IMPORTANCE

The need to rely on proper, simple, and accurate methods for age estimation in adults is still a world-wide issue. It has been well documented that teeth are more resistant than bones to the taphonomic processes, and that the use of methods for age estimation based on dental imaging assessment are not only less invasive than those based on osseous analysis, but also have shown similar or superior accuracy in adults.

OBJECTIVES

To summarise the results of some of the recently most recently cited methods for dental age estimation in adults, based on odontometric dental imaging analysis, to establish which is more accurate, accessible, and simple.

EVIDENCE REVIEW

A literature search from several databases was conducted from January 1995 to July 2016 with previously defined inclusion criteria.

CONCLUSION

Based on the findings of this review, it could be possible to suggest pulp/tooth area ratio calculation from first, upper canines and other single rooted teeth (lower premolars, upper central incisors), and a specific statistical analysis that considers the non-linear production of secondary dentine with age, as a reliable, easy, faster, and predictable method for dental age estimation in adults. The second recommended method is the pulp/tooth width-length ratio calculation. The use of specific population formulae is recommended, but to include data of individuals from different groups of population in the same analysis is not discouraged. A minimum sample size of at least 120 participants is recommended to obtain more reliable results. Methods based on volume calculation are time consuming and still need improvement.

Dental age estimation in the living after completion of third molar mineralization: new data for Gustafson's criteria

There is a need for dental age estimation methods after completion of the third molar mineralization. Degenerative dental characteristics appear to be suitable for forensic age diagnostics beyond the 18th year of life. In 2012, Olze et al. investigated the criteria studied by Gustafson using orthopantomograms. The objective of this study was to prove the applicability and reliability of this method with a large cohort and a wide age range, including older individuals. For this purpose, 2346 orthopantomograms of 1167 female and 1179 male Germans aged 15 to 70 years were reviewed. The characteristics of secondary dentin formation, cementum apposition, periodontal recession and attrition were evaluated in all the mandibular premolars. The correlation of the individual characteristics with the chronological age was examined by means of a stepwise multiple regression analysis, in which the chronological age formed the dependent variable. Following those results, R ² values amounted to 0.73 to 0.8; the standard error of estimate was 6.8 to 8.2 years. Fundamentally, the recommendation for conducting age estimations in the living by these methods can be shared. The values for the quality of the regression are, however, not precise enough for a reliable age estimation around regular retirement date ages. More precise regression formulae for the age group of 15 to 40 years of life are separately presented in this study. Further research should investigate the influence of ethnicity, dietary habits and modern health care on the degenerative characteristics in question.