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Dental age assessment: The applicability of Demirjian's method in South Indian children
Forensic Science International 94 (1998) 73–85
Dental age assessment: The applicability of Demirjian’s method in South Indian children Serene Koshy*, Shobha Tandon Department of Pedodontics and Preventive Dentistry, College of Dental Surgery, Manipal Academy of Higher Education (A deemed University), Manipal, India Received 3 February 1998; accepted 5 February 1998
Abstract The paper concerns the testing of Demirjian’s method of age assessment in South Indian children. Since previous studies have shown the inapplicability of Demirjian’s method on other populations, an attempt to compile a maturity standard for South Indian children was made. An additional independent indicator of age was employed, namely the skeletal age. The material was 184 South Indian children aged 5 to 15 years and an additional 34 children as the test sample. It was found that Demirjian’s method gave an overestimation of 3.04 and 2.82 years in males and females, respectively. The skeletal age was found to differ from the dental and chronologic age. It may be concluded that the accuracy of age estimation based on Demirjian’s method is not applicable for the South Indian children. For the population to be tested, it is imperative that individual assessment parameters need to be put forward because of wide ethnic differences. 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Age estimation; Dental age; Skeletal age; Demirjian
1. Introduction Age determination plays a great role in forensic medicine, pediatric endocrinology and is of particular interest in orthodontic and pedodontic treatment planning. Dental age is of particular interest to the pedodontist and orthodontist in the management of different types of malocclusions in relation to maxillo–facial growth. Dental age is estimated by comparing the dental development status in a person of unknown age with published *Corresponding author. 0379-0738 / 98 / $19.00 1998 Elsevier Science Ireland Ltd. All rights reserved. PII: S0379-0738( 98 )00034-6
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dental developmental surveys. Most of the methods employed for dental age determination were based on comparison of radiographic development of teeth with standard charts compiled from a large number of persons usually in a well defined geographic region. Nolla [1] assessed the age based on the appearance of the tooth radiographically. Demirjian et al. [2] formulated the method of dental age assessment by reference to the radiological appearances of the seven teeth on the left side of the mandible. Hagg and Matsson [3] found a high precision and accuracy with Demirjian’s method when applied to the younger age group rather than in the older ages. The authors concluded that the estimation of age is preferably done during early childhood. Nystrom et al. [4] found a more advanced dental maturation in Finnish children than the French–Canadian children and concluded that maturity standards should be based on studies made on the same population for which they are going to be used. Davis and Hagg [5] stated that Demirjian’s system could not be accurately applied to other population groups due to ethnic differences when it was tested on the Chinese population. Staaf et al. [6] concluded that the Canadian studies systematically gave an overestimate of about 6 to 10 months when used on a Scandinavian population. Besides the dental development, skeletal maturation has often been utilized for age estimations. Skeletal maturity is an important assessment in pediatric medicine, especially in orthopedic surgery and in endocrinology. The radiograph of the hand–wrist has been the most frequently used area of the skeleton due to the many centers available in this area that undergo changes at different times and rates. One of the most frequently applied methods to estimate skeletal age is the atlas of Greulich and Pyle [7]. Milner et al. [8] stated that the atlas has a valuable place in diagnosis. Chen et al. [9] found that 83–94% of the cases could be matched within 66 months discrepancy on using the atlas, resulting in a good degree of confidence for practical purposes. Relations between the dental and skeletal ages have been evaluated in order to correlate the two ages for purposes of diagnosis. Demirjian et al. [10] evaluated the interrelationships between the somatic, dental, skeletal and sexual maturity and implied that the mechanisms controlling dental development are independent of somatic or sexual maturity. Gulati et al. [11] found that the dental and skeletal ages had the maximum amount of correlation. Although various age assessment methods gave high degrees of reliability, ethnic differences between various population groups were found to affect the accuracy resulting in overestimation or underestimation of the dental age. Since the various studies for assessing the dental age have been conducted predominantly on the Western population, a similar assessment has been found to be lacking for Indian children. The aim of the present work was
1. To determine the dental developmental stages in the South Indian children and to test the applicability of Demirjian’s [2] criteria for maturity scoring in the dental age assessment of the same. 2. To compile a new maturity score for the South Indian population and test its applicability.
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3. To find the interrelationship between the obtained dental age with the respective skeletal ages.
2. Materials One hundred and eighty four children consisting of 93 males and 91 females were selected from ages 5 to 15 years in a simple stratified random sampling method. Age and sex distribution of the patients is shown in Fig. 1. The children selected were healthy, without any growth disorders and with all the mandibular permanent teeth (erupted or unerupted). The children had to be of South Indian origin of at least two generations. An additional 34 children (18% of the original samples) consisting of 23 males and 11 females were taken as the test sample. An orthopantomogram and a hand and wrist radiograph of the right and left side in a postero–anterior view was taken for each child. The radiographs selected were clear, of good quality, with all the lower permanent mandibular teeth present on the left side in the orthopantomogram, and all the carpal bones and phalanges clearly visible in the hand and wrist radiograph. The X-rays obtained were coded by a non-investigator in order to avoid bias during scoring of the radiographs. Both the orthopantomogram and the hand and wrist radiographs were given the same code for one child. The investigator did not know the chronologic age of the children when assessing the radiographs. Intra examiner variability was also avoided.
Fig. 1. Sex and age distribution of the sample.
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3. Methods
3.1. Dental method The orthopantomogram was scored according to the criteria given by Demirjian et al. [2]. Seven teeth present on the left side of the mandible were assessed. Each tooth having a stage was converted into a score using the conversion table given by Demirjian and Goldstein [12] for boys or girls, as appropriate. The scores of all seven teeth were added together to give the total maturity score. After the maturity score was calculated for the all the radiographs, the X-rays were decoded and the chronologic age of the child in years was noted according to the date of birth up to the time of taking of the radiograph. The maturity score was then converted to the dental age by referring to the table given by Demirjian [2] in order to obtain the estimated dental age in the Indian child.
3.2. Skeletal method The skeletal ages of the hand and wrist radiographs were assessed according to the criteria given in the ‘‘Radiographic Atlas’’ by Greulich and Pyle [7]. The right and left hand and wrist were assessed simultaneously. The radiograph was compared to the standard of the same sex in the atlas. The film was then compared with adjacent standards, both older and younger than the one which was to be assessed. The standard which superficially appeared to resemble the radiograph to be assessed most closely was selected. The carpal bones were studied in the order in which they usually appeared: Capitate (CAP), Hamate (HAM), Triquetral (TRI), Lunate (LUN), Scaphoid (SCA), Trapezium (TRM), Trapezoid (TRD), Pisiform (PSI). The adductor and flexor sesamoids (SES) of the thumb appeared in that order, usually several years after the Pisiform had begun to ossify [7].
3.3. Statistical analyses The chronologic age and the attained total maturity score were then assessed statistically by using the simple regression analysis with the chronologic age taken as the independent variable and the total maturity score as the dependent variable in order to obtain the estimated dental age (Table 1). For the convenience of statistical analysis, the samples were divided into ten groups for males and ten for females, according to the chronologic age. The difference between each group was 1 year. The groups were denoted with serial numbers ranging from one to ten. The various ages in both sexes were denoted as: Table 1 Regression equations Males Females
– –
Age50.115326 3 score 10.617206 Age50.115699 3 score 10.498981
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Chronologic age Obtained age Skeletal age (left) Skeletal age (right) Estimated age
– – – – –
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(CA) (OA) (SA) (SA) (EA)
The chronologic age is the age of the child in years from his date of birth to the time of taking of the radiographs. The obtained dental age is the calculated age from the regression analysis, i.e., the ages got by the regression equations after analysis of the chronologic age and the maturity scores for males and females, respectively. The estimated dental age is the age calculated on applying Demirjian’s criteria and the left and right skeletal ages are those of the respective sides on comparison with the radiographic atlas. The right and left hand wrist radiographs were tested using the correlation test and paired t-test to see if any significant difference was present. The obtained dental age was tested against the skeletal ages, the estimated dental ages and the chronologic age using the paired t-test. The maturity scores of the test sample were also assessed and the obtained dental age was substituted and the dental ages for the Indian children of the test sample were tested against their chronologic ages using a similar test.
4. Results The maturity scores of the 93 male and 91 female subjects were converted to the estimated dental age using the Demirjian’s conversion table [2] and the mean values of the various ages are presented in Tables 2 and 3 for males and females, respectively. The additional skeletal age determined was correlated between the right and left sides resulting in a high correlation coefficient of 0.997 and 0.994 in males and females, Table 2 The mean values of various ages in different age groups in males SampleNo.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Total mean
Age groups
Number of samples
EA
OA
CA
Overestimation (years) (EA2CA)
5.1–6.0 6.1–7.0 7.1–8.0 8.1–9.0 9.1–10.0 10.1–11.0 11.1–12.0 12.1–13.0 13.1–14.0 14.1–15.0
7 10 13 9 10 9 12 8 12 3
8.2460.27 8.9460.74 10.2062.28 10.1661.68 11.5561.62 12.7361.02 15.3460.43 16.8462.23 18.3061.31 18.7660.76
5.8460.50 7.1161.39 8.6361.67 8.7661.93 10.3560.91 11.0860.37 11.5060.44 11.7360.25 11.9560.16 11.9860.10
5.8060.23 6.5460.35 7.5960.34 8.6760.64 9.5660.28 10.3960.25 11.5160.31 12.6260.27 13.4660.25 14.6360.24
2.4460.04 2.4060.39 2.6461.94 1.4961.04 2.1661.34 2.3460.77 3.8360.12 4.2261.96 4.8461.06 4.1360.52
93
13.1061.23 10.0760.77
9.8960.31 3.0460.92
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Table 3 The mean values of various ages in different age groups in females SampleNo.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Total mean
Age groups
Number of samples
EA
OA
CA
Overestimation (years) (EA2CA)
5.1–6.0 6.1–7.0 7.1–8.0 8.1–9.0 9.1–10.0 10.1–11.0 11.1–12.0 12.1–13.0 13.1–14.0 14.1–15.0
6 10 13 8 12 6 10 10 12 4
7.2260.73 8.2860.77 9.1460.84 10.0861.21 12.9462.66 12.3962.78 14.4861.97 17.5861.13 17.6361.29 18.8460.42
5.6160.96 6.4961.29 8.1361.43 9.8160.98 11.0360.83 10.5961.50 11.5760.27 11.9360.16 11.9460.11 12.0460.04
5.8460.26 6.4860.35 7.4961.43 8.5660.20 9.6360.29 10.6560.28 11.4360.31 12.5160.29 13.5160.32 14.7060.21
1.8860.47 1.8060.42 1.6560.41 1.5261.01 3.3162.37 1.7462.50 3.0561.66 5.0760.84 4.1260.97 4.1460.22
91
12.8561.38 10.0860.75
9.9160.28 2.8261.10
respectively. There was no statistically significant difference observed between the two ages in both sexes with a P-value of 0.15 in males and 0.50 in females. Since there was a close correlation between the two sides, the skeletal age of the left side was taken for further comparison with the chronologic age, the estimated and the obtained ages. The estimated dental age was compared against the chronologic age in an attempt to see whether the same conversion could be used on the Indian population in both males and females. In both sexes, a highly significant difference of 0.0001 was observed (Table 4). The obtained dental age was tested against the chronologic age in males and females. This showed no significant difference with a P-value of 0.998 and 0.979, respectively (Table 4). The skeletal age was tested against the estimated age and the obtained age. In both sexes, a highly significant difference with P-value of 0.0001 was observed in all comparisons except that of the skeletal age with the obtained age in females where a significant difference was noted at 0.001 level. This indicated that the skeletal age did not correlate with either the estimated or obtained dental ages, or the chronologic age (Table 4). On comparison of the skeletal age of both sexes to find any significant difference between the maturation rates, a high significant difference with P-value of 0.0001 was noted showing that the skeletal maturation of males and females differed from each other with the latter having a higher mean value for the skeletal age. The estimated age was found to overestimate the age in South Indian children. An average overestimation of 3.04 years and 2.82 years was found in males and females, respectively, indicating that Demirjian’s [2] method did not give an accurate age assessment of the South Indian child (Table 4, Fig. 2). The chronologic age is plotted against the total maturity scores for males and females in Figs. 3 and 4 , respectively Orthopantomograms, in a test sample consisting of 23 males and 11 females, were graded according to the same criteria as in the original group. The maturity scores calculated from the radiographs were plotted on the regression graphs as shown in Figs. 5 and 6 for the respective sexes and were converted to the dental age. In order to test the
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Table 4 Means and mean differences between the chronologic age (CA), estimated dental age (EA), obtained age (OA) and skeletal age (SA) for different sexes Method
Mean6S.D.
Mean difference6S.D.
Males OA CA
EA SA OA Females OA CA
EA SA OA
Fig. 2. Mean values of the various ages in males and females.
P-value
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Fig. 3. Graph showing the relation between the total maturity scores and chronologic age in males.
validity of the dental age obtained, the paired t-test was carried out to check for any significant difference between the two ages. A P-value of 0.37 and 0.78 was observed in males and females, respectively, showing no significant difference between the chronologic age and the obtained dental age. This indicated that the obtained age was more accurate in the determination of the chronologic age (Table 5).
Fig. 4. Graph showing the relation between the total maturity scores and chronologic age in females.
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Fig. 5. Regression graph showing relation between obtained dental age and maturity score.
5. Discussion Methods for the determination of a child’s growth and development are of great value from both the medical and odontologic points of view. Although various methods for the age determinations do exist, a universal system has not been achieved due to the varying differences in different ethnic population groups. This study was done with the main objective of trying to determine the dental age of an Indian child using an estimation method followed by Demirjian [2] which was used on a French–Canadian population. Due to ethnic differences in the two population groups, i.e., the French–Canadian population and the South Indian population, the applicability of the method was tested. A sample size consisting of 184 children from South Indian origin of at least two generations were taken, who had no growth disorders and were normal. This was to avoid any irregularity in the results as abnormal or delayed growth can have a significant effect in the dental as well as the skeletal age as stated by Mornstad et al. [13] and Gulati et al. [11]. The radiological study of the hand and wrist is the single most useful method of studying the skeletal age as stated by Greulich and Pyle [7]. The atlas was based on the hand wrist radiographs of Boston school children population in America. Since there is no current norm that is currently used for the assessment of skeletal age in the Indian
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Fig. 6. Regression graph showing relation between obtained dental age and maturity score.
population as seen by Gulati et al. [11], the atlas was taken as a method of comparison in this study. Due to the orderly sequence of formation, the hand wrist is taken as one of the most reliable methods of skeletal age assessment. The Greulich and Pyle ‘‘Radiographic Atlas’’ [7] was preferred to the Tanner et al. [14] technique since the latter requires thorough familiarity with the rating process, an experienced observer and is time consuming. The atlas can be used successfully in nonspecialist clinics and can give a good degree of confidence for practical purposes [8,9]. Comparison between the skeletal ages of the males and females in the present study showed that the females had a higher skeletal age assessment indicating an early Table 5 Relation between the chronologic age (CA) and the obtained age (OA) in the test sample in males and females Method
Sex
Mean6S.D.
P-value
Males
CA OA
9.3462.91 9.6162.22
0.37
Females
CA OA
9.4361.69 9.3361.85
0.78
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maturation in Indian females. Pryor [15] and Roche [16] conducted studies where males and females were assessed separately and showed that there is a wide difference in dental calcification as well as the skeletal development. The orthopantomogram and hand and wrist radiographs were coded to avoid any bias on the part of the investigator by knowing the exact chronologic age as done by Davis and Hagg [5]. The dental age was calculated according to Demirjian’s [2] scoring criteria. The Demirjian [2] method is the dental counterpart of Tanner et al. [14] and its applicability has been tested on various other western populations. Hagg and Matsson [3] found high accuracy and precision in the method of age estimation on Swedish children. But Nystrom et al. [4] found a more advanced dental development in Finnish children and stated that a difference in the overall maturity exists among the white populations. In the present study, the estimated age was found to overestimate the age in the South Indian child. An average overestimation of 3.04 years and 2.82 years was found in males and females, respectively (Tables 2 and 3). Similar overestimation of the dental age was found in other population groups, probably due to cultural and ethnic differences between populations. Other probable causes of differences are the environmental factors such as the socio-economic status nutrition and dietary habits that vary in different population groups. Gulati et al. [11] stated that malnutrition can have an adverse effect on the dental and skeletal maturation. All the children in this study were healthy and taken from the same socio-economic group in order to minimize the differences between the samples. The estimated age was found to be much higher than the chronologic age and the obtained age in males and females (Table 4). Therefore the estimated age of the South Indian children was observed to be at a higher level than the French–Canadian population on whose dental development, Demirjian’s values for the estimated age were based. In males and females, a higher amount of overestimation was seen in the older age groups ranging from 12 to 15 years (Tables 1 and 2). The higher overestimation of the dental age observed on the older age groups could probably be due to the pre–pubertal or pubertal growth changes pertinent during this age period. Hagg and Taranger [17] found more dental advancement in relation to the pubertal growth spurt. In the present study, on comparison between the mean values of the chronologic and estimated ages in both the sexes, females showed a lesser amount of overestimation of age when compared to the males. This indicated that the females showed an earlier maturation in the dental development than the males, which can be comparable to the early maturation of skeletal age also seen in females. It can be inferred from these observations that the South Indian females were more advanced than the males which was found to be in agreement with the study of Demirjian and Levesque [18]. Figs. 5 and 6 gives the regression graphs plotted against the obtained age and the maturity score in males and females of the main sample. The test sample showed no significant difference between the chronologic age and the obtained age indicating that the obtained ages calculated from the graphs are closer to the chronologic age of the South Indian child than the estimated age which is according to Demirjian’s conversion. Ethnic differences between populations dictate that new scores and grading criteria are needed for individual populations as it is observed in the present study for Indian
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children. However, further studies are needed with extensive and large numbers of samples in order to compile the full table of the dental age conversion from the maturity scores. Studies are also required in order to formulate new scoring measures for the Indian children.
6. Conclusion From this study, it can be inferred that the assessment of dental age is dependent on the ethnic group on which it is to be tested. The Demirjian conversion of the maturity score to the dental age was not applicable in the South Indian children. An attempt to formulate new norms for the maturity score and conversion of the same to the dental age was made. The assessed skeletal age did not relate with the dental age indicating that the determination of one of the ages is not a satisfactory method of knowing the other age. Although various methods of age assessment are used, the applicability can vary due to the wide ethnic differences between populations which can influence the tooth formation, development and eruption upon which the assessment parameters are based. It is therefore imperative, that the population to be tested has to be assessed on a scale devised on the same population group.
Acknowledgements The authors would like to thank Dr. Kenneth Brown, Director, Forensic Odontology Unit, University of Adelaide, Australia, for his valuable guidance in promoting the field of Forensic Odontology research in our department.
References [1] C.M. Nolla, The development of permanent teeth, J. Dent. Child. 27 (1960) 254. [2] A. Demirjian, H. Goldstein, J.R. Tanner, A new system of dental age assessment, Hum. Biol. 45 (1973) 211–227. [3] U. Hagg, L. Matsson, Dental maturity as an indicator of chronological age: the accuracy and precision of three methods, Eur. J. Orthod. 7 (1985) 25–34. [4] M. Nystrom, J. Haataja, M. Kataja, M. Evalahti, L. Peck, E. Kleemola-Kujala, Dental maturity in Finnish children, estimated from the development of seven permanent mandibular teeth, Acta. Odontol. Scand. 44 (1986) 193–198. [5] P.J. Davis, U. Hagg, The accuracy and precision of the ‘‘Demirjian System’’ when used for age determination in Chinese children, Swed. Dent. J. 18 (1994) 113–116. [6] V. Staaf, H. Mornstad, U. Welander, Age determination with the aid of tooth development: a test of the reliability and validity, Scand. J. Dent. Res. 99 (1991) 281–286. [7] W.W. Greulich, S.I. Pyle, Radiographic Atlas of Skeletal Development of the Hand and Wrist, 2nd Ed., Stanford University Press, CA, USA, 1959. [8] G.R. Milner, R.K. Levick, R. Kay, Assessment of bone age: A comparison of the Greulich and Pyle and the Tanner and Whitehouse methods, Clin. Radiol. 37 (1986) 119–121.
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[9] S.T. Chen, F.C. Jee, T.B. Mohamed, Bone age of Malaysian children aged 12 to 28 months, J. Singapore Pediatr. Soc. 32 (1990) 97–101. [10] A. Demirjian, P.H. Buschang, R. Tanguay, D.P. Patterson, Interrelationships among measures of somatic, skeletal, dental and sexual maturity, Am. J. Orthod. 88 (1985) 433–438. [11] A. Gulati, J.R. Taneja, S.L. Chopra, S. Madan, Interrelationship between dental, skeletal and chronological ages in well-nourished and mal-nourished children, J. Indian. Soc. Pedo. Prev. Dent. 8 (1990) 19–23. [12] A. Demirjian, H. Goldstein, New systems for dental maturity based on seven and four teeth, Ann. Hum. Biol. 3 (1976) 411–421. [13] H. Mornstad, H. Staaf, U. Welander, Age estimation with the aid of tooth development: A new method based on objective measurements, Scand. J. Dent. Res. 102 (1994) 137–143. [14] J.M. Tanner, R.H. Whitehouse, M.J.R. Healy, A new system for estimating skeletal maturity from the hand and wrist with standards derived from a study of 2,600 healthy British children, Centre International de l’Enfance, Paris, 1962. [15] J.W. Pryor, The hereditary nature of variation in the ossification of bones, Anat. Rec. 1 (1907) 84–88. [16] A.F. Roche, Associations between the bones of the handwrist, Am. J. Phys. Anthropol. 33 (1970) 341–348. [17] U. Hagg, J. Taranger, Maturation indicators and the pubertal growth spurt, Am. J. Orthod. 82 (1982) 309. [18] A. Demirjian, G.Y. Levesque, Sexual differences in dental development and prediction of emergence, J. Dent. Res. 59 (1980) 1110–1122.
Dental age assessment: The applicability of Demirjian’s method in South Indian children Serene Koshy*, Shobha Tandon Department of Pedodontics and Preventive Dentistry, College of Dental Surgery, Manipal Academy of Higher Education (A deemed University), Manipal, India Received 3 February 1998; accepted 5 February 1998
Abstract The paper concerns the testing of Demirjian’s method of age assessment in South Indian children. Since previous studies have shown the inapplicability of Demirjian’s method on other populations, an attempt to compile a maturity standard for South Indian children was made. An additional independent indicator of age was employed, namely the skeletal age. The material was 184 South Indian children aged 5 to 15 years and an additional 34 children as the test sample. It was found that Demirjian’s method gave an overestimation of 3.04 and 2.82 years in males and females, respectively. The skeletal age was found to differ from the dental and chronologic age. It may be concluded that the accuracy of age estimation based on Demirjian’s method is not applicable for the South Indian children. For the population to be tested, it is imperative that individual assessment parameters need to be put forward because of wide ethnic differences. 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Age estimation; Dental age; Skeletal age; Demirjian
1. Introduction Age determination plays a great role in forensic medicine, pediatric endocrinology and is of particular interest in orthodontic and pedodontic treatment planning. Dental age is of particular interest to the pedodontist and orthodontist in the management of different types of malocclusions in relation to maxillo–facial growth. Dental age is estimated by comparing the dental development status in a person of unknown age with published *Corresponding author. 0379-0738 / 98 / $19.00 1998 Elsevier Science Ireland Ltd. All rights reserved. PII: S0379-0738( 98 )00034-6
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dental developmental surveys. Most of the methods employed for dental age determination were based on comparison of radiographic development of teeth with standard charts compiled from a large number of persons usually in a well defined geographic region. Nolla [1] assessed the age based on the appearance of the tooth radiographically. Demirjian et al. [2] formulated the method of dental age assessment by reference to the radiological appearances of the seven teeth on the left side of the mandible. Hagg and Matsson [3] found a high precision and accuracy with Demirjian’s method when applied to the younger age group rather than in the older ages. The authors concluded that the estimation of age is preferably done during early childhood. Nystrom et al. [4] found a more advanced dental maturation in Finnish children than the French–Canadian children and concluded that maturity standards should be based on studies made on the same population for which they are going to be used. Davis and Hagg [5] stated that Demirjian’s system could not be accurately applied to other population groups due to ethnic differences when it was tested on the Chinese population. Staaf et al. [6] concluded that the Canadian studies systematically gave an overestimate of about 6 to 10 months when used on a Scandinavian population. Besides the dental development, skeletal maturation has often been utilized for age estimations. Skeletal maturity is an important assessment in pediatric medicine, especially in orthopedic surgery and in endocrinology. The radiograph of the hand–wrist has been the most frequently used area of the skeleton due to the many centers available in this area that undergo changes at different times and rates. One of the most frequently applied methods to estimate skeletal age is the atlas of Greulich and Pyle [7]. Milner et al. [8] stated that the atlas has a valuable place in diagnosis. Chen et al. [9] found that 83–94% of the cases could be matched within 66 months discrepancy on using the atlas, resulting in a good degree of confidence for practical purposes. Relations between the dental and skeletal ages have been evaluated in order to correlate the two ages for purposes of diagnosis. Demirjian et al. [10] evaluated the interrelationships between the somatic, dental, skeletal and sexual maturity and implied that the mechanisms controlling dental development are independent of somatic or sexual maturity. Gulati et al. [11] found that the dental and skeletal ages had the maximum amount of correlation. Although various age assessment methods gave high degrees of reliability, ethnic differences between various population groups were found to affect the accuracy resulting in overestimation or underestimation of the dental age. Since the various studies for assessing the dental age have been conducted predominantly on the Western population, a similar assessment has been found to be lacking for Indian children. The aim of the present work was
1. To determine the dental developmental stages in the South Indian children and to test the applicability of Demirjian’s [2] criteria for maturity scoring in the dental age assessment of the same. 2. To compile a new maturity score for the South Indian population and test its applicability.
S. Koshy, S. Tandon / Forensic Science International 94 (1998) 73 – 85
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3. To find the interrelationship between the obtained dental age with the respective skeletal ages.
2. Materials One hundred and eighty four children consisting of 93 males and 91 females were selected from ages 5 to 15 years in a simple stratified random sampling method. Age and sex distribution of the patients is shown in Fig. 1. The children selected were healthy, without any growth disorders and with all the mandibular permanent teeth (erupted or unerupted). The children had to be of South Indian origin of at least two generations. An additional 34 children (18% of the original samples) consisting of 23 males and 11 females were taken as the test sample. An orthopantomogram and a hand and wrist radiograph of the right and left side in a postero–anterior view was taken for each child. The radiographs selected were clear, of good quality, with all the lower permanent mandibular teeth present on the left side in the orthopantomogram, and all the carpal bones and phalanges clearly visible in the hand and wrist radiograph. The X-rays obtained were coded by a non-investigator in order to avoid bias during scoring of the radiographs. Both the orthopantomogram and the hand and wrist radiographs were given the same code for one child. The investigator did not know the chronologic age of the children when assessing the radiographs. Intra examiner variability was also avoided.
Fig. 1. Sex and age distribution of the sample.
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3. Methods
3.1. Dental method The orthopantomogram was scored according to the criteria given by Demirjian et al. [2]. Seven teeth present on the left side of the mandible were assessed. Each tooth having a stage was converted into a score using the conversion table given by Demirjian and Goldstein [12] for boys or girls, as appropriate. The scores of all seven teeth were added together to give the total maturity score. After the maturity score was calculated for the all the radiographs, the X-rays were decoded and the chronologic age of the child in years was noted according to the date of birth up to the time of taking of the radiograph. The maturity score was then converted to the dental age by referring to the table given by Demirjian [2] in order to obtain the estimated dental age in the Indian child.
3.2. Skeletal method The skeletal ages of the hand and wrist radiographs were assessed according to the criteria given in the ‘‘Radiographic Atlas’’ by Greulich and Pyle [7]. The right and left hand and wrist were assessed simultaneously. The radiograph was compared to the standard of the same sex in the atlas. The film was then compared with adjacent standards, both older and younger than the one which was to be assessed. The standard which superficially appeared to resemble the radiograph to be assessed most closely was selected. The carpal bones were studied in the order in which they usually appeared: Capitate (CAP), Hamate (HAM), Triquetral (TRI), Lunate (LUN), Scaphoid (SCA), Trapezium (TRM), Trapezoid (TRD), Pisiform (PSI). The adductor and flexor sesamoids (SES) of the thumb appeared in that order, usually several years after the Pisiform had begun to ossify [7].
3.3. Statistical analyses The chronologic age and the attained total maturity score were then assessed statistically by using the simple regression analysis with the chronologic age taken as the independent variable and the total maturity score as the dependent variable in order to obtain the estimated dental age (Table 1). For the convenience of statistical analysis, the samples were divided into ten groups for males and ten for females, according to the chronologic age. The difference between each group was 1 year. The groups were denoted with serial numbers ranging from one to ten. The various ages in both sexes were denoted as: Table 1 Regression equations Males Females
– –
Age50.115326 3 score 10.617206 Age50.115699 3 score 10.498981
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Chronologic age Obtained age Skeletal age (left) Skeletal age (right) Estimated age
– – – – –
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(CA) (OA) (SA) (SA) (EA)
The chronologic age is the age of the child in years from his date of birth to the time of taking of the radiographs. The obtained dental age is the calculated age from the regression analysis, i.e., the ages got by the regression equations after analysis of the chronologic age and the maturity scores for males and females, respectively. The estimated dental age is the age calculated on applying Demirjian’s criteria and the left and right skeletal ages are those of the respective sides on comparison with the radiographic atlas. The right and left hand wrist radiographs were tested using the correlation test and paired t-test to see if any significant difference was present. The obtained dental age was tested against the skeletal ages, the estimated dental ages and the chronologic age using the paired t-test. The maturity scores of the test sample were also assessed and the obtained dental age was substituted and the dental ages for the Indian children of the test sample were tested against their chronologic ages using a similar test.
4. Results The maturity scores of the 93 male and 91 female subjects were converted to the estimated dental age using the Demirjian’s conversion table [2] and the mean values of the various ages are presented in Tables 2 and 3 for males and females, respectively. The additional skeletal age determined was correlated between the right and left sides resulting in a high correlation coefficient of 0.997 and 0.994 in males and females, Table 2 The mean values of various ages in different age groups in males SampleNo.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Total mean
Age groups
Number of samples
EA
OA
CA
Overestimation (years) (EA2CA)
5.1–6.0 6.1–7.0 7.1–8.0 8.1–9.0 9.1–10.0 10.1–11.0 11.1–12.0 12.1–13.0 13.1–14.0 14.1–15.0
7 10 13 9 10 9 12 8 12 3
8.2460.27 8.9460.74 10.2062.28 10.1661.68 11.5561.62 12.7361.02 15.3460.43 16.8462.23 18.3061.31 18.7660.76
5.8460.50 7.1161.39 8.6361.67 8.7661.93 10.3560.91 11.0860.37 11.5060.44 11.7360.25 11.9560.16 11.9860.10
5.8060.23 6.5460.35 7.5960.34 8.6760.64 9.5660.28 10.3960.25 11.5160.31 12.6260.27 13.4660.25 14.6360.24
2.4460.04 2.4060.39 2.6461.94 1.4961.04 2.1661.34 2.3460.77 3.8360.12 4.2261.96 4.8461.06 4.1360.52
93
13.1061.23 10.0760.77
9.8960.31 3.0460.92
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Table 3 The mean values of various ages in different age groups in females SampleNo.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Total mean
Age groups
Number of samples
EA
OA
CA
Overestimation (years) (EA2CA)
5.1–6.0 6.1–7.0 7.1–8.0 8.1–9.0 9.1–10.0 10.1–11.0 11.1–12.0 12.1–13.0 13.1–14.0 14.1–15.0
6 10 13 8 12 6 10 10 12 4
7.2260.73 8.2860.77 9.1460.84 10.0861.21 12.9462.66 12.3962.78 14.4861.97 17.5861.13 17.6361.29 18.8460.42
5.6160.96 6.4961.29 8.1361.43 9.8160.98 11.0360.83 10.5961.50 11.5760.27 11.9360.16 11.9460.11 12.0460.04
5.8460.26 6.4860.35 7.4961.43 8.5660.20 9.6360.29 10.6560.28 11.4360.31 12.5160.29 13.5160.32 14.7060.21
1.8860.47 1.8060.42 1.6560.41 1.5261.01 3.3162.37 1.7462.50 3.0561.66 5.0760.84 4.1260.97 4.1460.22
91
12.8561.38 10.0860.75
9.9160.28 2.8261.10
respectively. There was no statistically significant difference observed between the two ages in both sexes with a P-value of 0.15 in males and 0.50 in females. Since there was a close correlation between the two sides, the skeletal age of the left side was taken for further comparison with the chronologic age, the estimated and the obtained ages. The estimated dental age was compared against the chronologic age in an attempt to see whether the same conversion could be used on the Indian population in both males and females. In both sexes, a highly significant difference of 0.0001 was observed (Table 4). The obtained dental age was tested against the chronologic age in males and females. This showed no significant difference with a P-value of 0.998 and 0.979, respectively (Table 4). The skeletal age was tested against the estimated age and the obtained age. In both sexes, a highly significant difference with P-value of 0.0001 was observed in all comparisons except that of the skeletal age with the obtained age in females where a significant difference was noted at 0.001 level. This indicated that the skeletal age did not correlate with either the estimated or obtained dental ages, or the chronologic age (Table 4). On comparison of the skeletal age of both sexes to find any significant difference between the maturation rates, a high significant difference with P-value of 0.0001 was noted showing that the skeletal maturation of males and females differed from each other with the latter having a higher mean value for the skeletal age. The estimated age was found to overestimate the age in South Indian children. An average overestimation of 3.04 years and 2.82 years was found in males and females, respectively, indicating that Demirjian’s [2] method did not give an accurate age assessment of the South Indian child (Table 4, Fig. 2). The chronologic age is plotted against the total maturity scores for males and females in Figs. 3 and 4 , respectively Orthopantomograms, in a test sample consisting of 23 males and 11 females, were graded according to the same criteria as in the original group. The maturity scores calculated from the radiographs were plotted on the regression graphs as shown in Figs. 5 and 6 for the respective sexes and were converted to the dental age. In order to test the
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Table 4 Means and mean differences between the chronologic age (CA), estimated dental age (EA), obtained age (OA) and skeletal age (SA) for different sexes Method
Mean6S.D.
Mean difference6S.D.
Males OA CA
EA SA OA Females OA CA
EA SA OA
Fig. 2. Mean values of the various ages in males and females.
P-value
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Fig. 3. Graph showing the relation between the total maturity scores and chronologic age in males.
validity of the dental age obtained, the paired t-test was carried out to check for any significant difference between the two ages. A P-value of 0.37 and 0.78 was observed in males and females, respectively, showing no significant difference between the chronologic age and the obtained dental age. This indicated that the obtained age was more accurate in the determination of the chronologic age (Table 5).
Fig. 4. Graph showing the relation between the total maturity scores and chronologic age in females.
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Fig. 5. Regression graph showing relation between obtained dental age and maturity score.
5. Discussion Methods for the determination of a child’s growth and development are of great value from both the medical and odontologic points of view. Although various methods for the age determinations do exist, a universal system has not been achieved due to the varying differences in different ethnic population groups. This study was done with the main objective of trying to determine the dental age of an Indian child using an estimation method followed by Demirjian [2] which was used on a French–Canadian population. Due to ethnic differences in the two population groups, i.e., the French–Canadian population and the South Indian population, the applicability of the method was tested. A sample size consisting of 184 children from South Indian origin of at least two generations were taken, who had no growth disorders and were normal. This was to avoid any irregularity in the results as abnormal or delayed growth can have a significant effect in the dental as well as the skeletal age as stated by Mornstad et al. [13] and Gulati et al. [11]. The radiological study of the hand and wrist is the single most useful method of studying the skeletal age as stated by Greulich and Pyle [7]. The atlas was based on the hand wrist radiographs of Boston school children population in America. Since there is no current norm that is currently used for the assessment of skeletal age in the Indian
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Fig. 6. Regression graph showing relation between obtained dental age and maturity score.
population as seen by Gulati et al. [11], the atlas was taken as a method of comparison in this study. Due to the orderly sequence of formation, the hand wrist is taken as one of the most reliable methods of skeletal age assessment. The Greulich and Pyle ‘‘Radiographic Atlas’’ [7] was preferred to the Tanner et al. [14] technique since the latter requires thorough familiarity with the rating process, an experienced observer and is time consuming. The atlas can be used successfully in nonspecialist clinics and can give a good degree of confidence for practical purposes [8,9]. Comparison between the skeletal ages of the males and females in the present study showed that the females had a higher skeletal age assessment indicating an early Table 5 Relation between the chronologic age (CA) and the obtained age (OA) in the test sample in males and females Method
Sex
Mean6S.D.
P-value
Males
CA OA
9.3462.91 9.6162.22
0.37
Females
CA OA
9.4361.69 9.3361.85
0.78
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maturation in Indian females. Pryor [15] and Roche [16] conducted studies where males and females were assessed separately and showed that there is a wide difference in dental calcification as well as the skeletal development. The orthopantomogram and hand and wrist radiographs were coded to avoid any bias on the part of the investigator by knowing the exact chronologic age as done by Davis and Hagg [5]. The dental age was calculated according to Demirjian’s [2] scoring criteria. The Demirjian [2] method is the dental counterpart of Tanner et al. [14] and its applicability has been tested on various other western populations. Hagg and Matsson [3] found high accuracy and precision in the method of age estimation on Swedish children. But Nystrom et al. [4] found a more advanced dental development in Finnish children and stated that a difference in the overall maturity exists among the white populations. In the present study, the estimated age was found to overestimate the age in the South Indian child. An average overestimation of 3.04 years and 2.82 years was found in males and females, respectively (Tables 2 and 3). Similar overestimation of the dental age was found in other population groups, probably due to cultural and ethnic differences between populations. Other probable causes of differences are the environmental factors such as the socio-economic status nutrition and dietary habits that vary in different population groups. Gulati et al. [11] stated that malnutrition can have an adverse effect on the dental and skeletal maturation. All the children in this study were healthy and taken from the same socio-economic group in order to minimize the differences between the samples. The estimated age was found to be much higher than the chronologic age and the obtained age in males and females (Table 4). Therefore the estimated age of the South Indian children was observed to be at a higher level than the French–Canadian population on whose dental development, Demirjian’s values for the estimated age were based. In males and females, a higher amount of overestimation was seen in the older age groups ranging from 12 to 15 years (Tables 1 and 2). The higher overestimation of the dental age observed on the older age groups could probably be due to the pre–pubertal or pubertal growth changes pertinent during this age period. Hagg and Taranger [17] found more dental advancement in relation to the pubertal growth spurt. In the present study, on comparison between the mean values of the chronologic and estimated ages in both the sexes, females showed a lesser amount of overestimation of age when compared to the males. This indicated that the females showed an earlier maturation in the dental development than the males, which can be comparable to the early maturation of skeletal age also seen in females. It can be inferred from these observations that the South Indian females were more advanced than the males which was found to be in agreement with the study of Demirjian and Levesque [18]. Figs. 5 and 6 gives the regression graphs plotted against the obtained age and the maturity score in males and females of the main sample. The test sample showed no significant difference between the chronologic age and the obtained age indicating that the obtained ages calculated from the graphs are closer to the chronologic age of the South Indian child than the estimated age which is according to Demirjian’s conversion. Ethnic differences between populations dictate that new scores and grading criteria are needed for individual populations as it is observed in the present study for Indian
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children. However, further studies are needed with extensive and large numbers of samples in order to compile the full table of the dental age conversion from the maturity scores. Studies are also required in order to formulate new scoring measures for the Indian children.
6. Conclusion From this study, it can be inferred that the assessment of dental age is dependent on the ethnic group on which it is to be tested. The Demirjian conversion of the maturity score to the dental age was not applicable in the South Indian children. An attempt to formulate new norms for the maturity score and conversion of the same to the dental age was made. The assessed skeletal age did not relate with the dental age indicating that the determination of one of the ages is not a satisfactory method of knowing the other age. Although various methods of age assessment are used, the applicability can vary due to the wide ethnic differences between populations which can influence the tooth formation, development and eruption upon which the assessment parameters are based. It is therefore imperative, that the population to be tested has to be assessed on a scale devised on the same population group.
Acknowledgements The authors would like to thank Dr. Kenneth Brown, Director, Forensic Odontology Unit, University of Adelaide, Australia, for his valuable guidance in promoting the field of Forensic Odontology research in our department.
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