|Year : 2013 | Volume
| Issue : 2 | Page : 63-68
Estimation and comparison of dental, skeletal and chronologic age in Bangalore south school going children
PH Shilpa, RS Sunil, K Sapna, NC Kumar
Departments of Pedodontics and Preventive Dentistry, A.E.C.S. Maaruti College of Dental Sciences and Research Centre, Bangalore, Karnataka, India
|Date of Web Publication||26-Jul-2013|
P H Shilpa
Department of Pedodontic and Preventive Dentistry, A.E.C.S. Maaruti College of Dental Sciences And Research Centre, 108 Hulimavu Tank Band Road, BTM 6th Stage, 1st Phase, Off Bannerghatta Road, Kammanhalli (Near Meenakshi Temple), Bangalore, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective : Precise evaluation of the developmental stages of a child is an integral part of both diagnosis and treatment planning of pediatric patients and also essential in forensic medicine and dentistry. As human growth shows considerable variation in chronological age, physiological maturity is preferred over chronological age in the estimation of person's exact age. Materials and Methods : Two hundred and fifty children consisting of 124 girls and 126 boys were selected randomly from the age group of 6-15 years. They were divided into 10 groups based on their age. The chronological age was determined by their date of birth as per the school records. An orthopantomogram and left hand-wrist radiographs was taken for each child to assess the dental age through Demirjian's method and skeletal age through the atlas of Greulich and Pyle's method respectively. Result : The dental age showed a significant correlation (P < 0.05) with chronological age in group 1 and 5 in males and group 3 and 7 females, whereas skeletal age showed a significant correlation with chronological age in group 3, 5, 9, and 10 in males and 1, 2, 5, 9, and 10 years in females. Conclusion : Demirjian's method of dental age estimation and Greulich and Pyle's method of skeletal age estimation showed accuracy only in certain age groups in the school children of Bangalore.
Keywords: Age estimation, chronological age, Demirjian′s dental age, Greulich and Pyle′s atlas
|How to cite this article:|
Shilpa P H, Sunil R S, Sapna K, Kumar N C. Estimation and comparison of dental, skeletal and chronologic age in Bangalore south school going children. J Indian Soc Pedod Prev Dent 2013;31:63-8
|How to cite this URL:|
Shilpa P H, Sunil R S, Sapna K, Kumar N C. Estimation and comparison of dental, skeletal and chronologic age in Bangalore south school going children. J Indian Soc Pedod Prev Dent [serial online] 2013 [cited 2020 Feb 24];31:63-8. Available from: http://www.jisppd.com/text.asp?2013/31/2/63/115696
| Introduction|| |
"Growth and development of a child has long fascinated poets, parents and paediatricians, but the diversity in its expression has left a lot unsatisfied."
Physiologic age or developmental age are measures for describing the status of an individual child, whereas chronologic or calendric age convey only a rough approximation of this status because of the range in the development observed for any given age. Physiologic age is defined as progress toward completeness of development or maturity in the individual child. The concept of physiologic age is based upon the degree of maturation of different tissue systems in the human body, like-skeletal age, morphological age, secondary sexual character age, age assessed by amino acid racemization, dental age, and stature or weight. These criteria can be applied separately or together to assess the degree of physiological maturity of an individual. 
In 1837, Dr. Edwin Saunder established the eruption pattern of the teeth as a better criterion for age estimation than height. Thereafter, examination of the teeth became the official method for determining the age. Dental age is of particular interest to the pedodontist and orthodontist in the management of different types of malocclusions in relation to maxillofacial growth. It can be determined by the stage of tooth eruption or the stage of tooth calcification. 
Besides dental development, skeletal maturity is also an important tool for age estimation. The fully developed human adult skeleton has 206 bones. The genesis, growth and degradational changes in these bones throughout life can be used to estimate the age of the individual. Much like dental development, many of these changes occur in an observable consistent sequence during a reasonably definite time period in the development of the human body. The changes are age related and occur during a limited and distinct time frame common to most human beings. It is these properties that allow us to use these changes to estimate the age of an individual.
The hand-wrist radiograph is commonly used for skeletal developmental assessment as skeletal developmental stages of the hand and wrist have been shown to be closely associated with pubertal growth. It is also used more frequently due to the many centers available in this area that can undergo changes at different times and rates. 
Relation between the dental and skeletal ages have been evaluated in order to correlate the two ages for the purpose of diagnosis and treatment planning. 
Although various age assessment methods have given high degrees of reliability, ethnic differences between various population groups were found to affect the accuracy. Various studies for assessing the dental and skeletal age have been conducted predominantly on the Western population; however a similar assessment has been lacking for Indian children. Hence, the present study is designed to determine whether the standards of dental maturation given by Demirjian et al. and the atlas given by Greulich and Pyle's skeletal maturation are applicable to the school children of Bangalore South zone and also to assess the relationship between the obtained dental, skeletal age, and chronological age.
The present study was conducted in the Department of Pedodontics and Preventive Dentistry, A.E.C.S. Maaruthi College of Dental Sciences and Research Centre, Bangalore. The study consisted of 250 children (124 girls and 126 boys) who were selected randomly from the age group of 6-15 years. The selected children were well- nourished cooperative, caries free, and clinically free from any developmental, endocrine, nutritional or mental disorders, which might affect the development of the subject. Children were also free from any past medical illness. Only those children who had all mandibular permanent teeth (erupted and unerupted) were included in the study. Subjects who have undergone previous orthodontic treatment or extraction of any permanent teeth were excluded from the study.
Their chronological age was determined as per records by their date of birth or as per the school records. An orthopantomogram and hand-wrist radiograph of the left hand in postero-anterior view was taken for each child. The radiographs selected were clear, of good quality, with all the permanent mandibular teeth present and all the carpal bones and phalanges clearly visible. The orthopantomogram was scored according to the criteria given by Demirjian et al.  [Figure 1] Seven teeth present on the left side of the mandible were assessed. The developmental stages of each tooth were converted into a score using the conversion table given by Demirjian and Goldstein for boys and girls as appropriate. The scores of all seven teeth were added together to give the total maturity score, which was converted to dental age by referring to the table given by Demirjian (1973) in order to get the dental age.  The skeletal age of the hand and wrist radiographs were assessed according to the criteria given in the radiographic atlas by Greulich and Pyle [Figure 2]. 
|Figure 1: OPG image of a child depicting the various developmental stages of mandibular teeth scored according to Demirjian's criteria. D - The crown formation is completed down to the cemento-enamel junction; beginning of root formation is seen in the form of a spicule, E - The root length is less than the crown height, F - The root length is equal to or greater than the crown height, G - The walls of the root canal are parallel and are still partially open|
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|Figure 2: Hand wrist radiograph of the same child. The order of appearance of the individual carpal bones is: Capitate, Hamate, Triquetral, Lunate, Trapezium, Trapezoid, Navicular or Scaphoid and Pisiform|
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Simple linear regression analysis was carried out for prediction of chronologic age, skeletal age and dental age
Pearson correlation co-efficient analysis is used for analyzing chronologic age, dental age and skeletal age
Student t-test has been used to compare the different values
| Results|| |
The estimated dental age through Demirjian's method and estimated skeletal age through Greulich and Pyle's method was compared to the chronologic age in 126 boys and 124 girls of Bangalore south school going children.
[Table 1] depicts the chronologic age, dental and skeletal age of male, female and combined population of various age groups. The P value and the mean difference values in male, female, and combined population of various age groups are also presented in [Table 1].
|Table 1: Dental, chronological and skeletal age in male, female, and combined population|
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When chronological age was compared to dental age a significant co-relation was seen in group 1 and group 5 in the male, group 3 and group 7 in female and groups 3, 5, and 7 in the combined population respectively.
Similarly skeletal age was compared against chronological age in individual age groups. A significant accuracy was observed in the age groups 3, 5, 9, and 10 in male, groups 1, 2, 5, 9, and 10 years in female and groups 2, 3, 5, 7, 9, and 10 in the combined population.
| Discussion|| |
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 determination do exist, a universal system has not been developed due to the varying differences in different ethnic population groups. 
Age estimation by means of tooth development is a well-established predictor of age during childhood. Tooth development is an accurate measure than chronologic age and is independent of exogenic factors, e.g. diseases or malnutrition, unlike skeletal age, body height and weight measurement.  Demirjian's method of dental age estimation is most widely researched and applied technique, because of its simplicity as well as radiographic and schematic illustrations of the tooth development and accompanying description. 
Bone age is frequently used as a diagnostic tool for the evaluation of endocrine, orthopedic and various genetic disorders. As regards bone mineralization, the growth of several parts of the body and also the appearance of ossification centers, their morphology, size, and fusion can also be used for age estimation. Clavicle, knee, hand-wrist and the cervical bone are the most frequently studied. The Greulich and Pyle's atlas was based on the hand wrist radiographs of Boston school children population in America.  The Greulich and Pyle "radiographic atlas" was preferred over other method of skeletal age estimation as the atlas does not require thorough familiarity with the rating process, does not require an experienced observer and is not time consuming.
The Orthopantomogram and hand wrist radiographs were coded to avoid any bias on the part of the investigator. The international agreement for the unification of anthropometric measurements to be made on living subjects drawn up at the Monaco and Geneva Conferences of Physical Anthropologists in 1906 and 1912, respectively, specified that measurements be made of the left rather than the right side of the body and of the left extremities. It was stated that in case of right and left extremities, the number of right handed person in a population is much larger than the number of left handed ones and therefore left hand is somewhat less likely to be maimed or injured than the right hand;  hence, the left side of the body that is left hand-wrist and left side of the mandible were considered.
In the present study, the individual age groups of the male and female population were assessed for correlation and comparison between the dental and the chronological age. Demirjian's standards of dental age estimation showed inaccuracy when applied to the total male and female population; however, it showed significant accuracy in specific age group 1 and group 5 in male and group 3 and group 7 in female respectively. This infers that, the standards given by Demirjian for dental age estimation may not be suitable for this population, which is in accordance to various studies done on different population. ,,,,,, Demirjian's methodology has shown overestimation of dental age in males between 12 years and 13 years age group. The higher overestimation of the dental age observed in the older age groups could probably be due to the pre-pubertal or pubertal growth changes pertinent during this period. Hagg and Taranger found more dental advancement in relation to the pubertal growth spurts. , The older age groups that is group 9 and group 10 showed less variation in dental age estimation in both male and female study samples, which could be due to the less disparity seen in that particular stage of tooth development where the root development with closure of apex and formation of a well-defined periodontal ligament has occurred. It further implies that, though specific age groups in both the sexes showed high accuracy, it did not show significant co-relation in the entire population. Hence, questioning the applicability of this method on Bangalore South zone school children as was similar to previous studies. ,,,,,,
Similarly, when the skeletal age and the chronological age were compared, a significant accuracy was observed in the group 3, 5, 9, and 10 in male and in females, a significant accuracy was observed in the age group 1, 2, 5, 9, and 10. The above result inferred that the female showed more accuracy when skeletal age was compared with chronological age in comparison with male. This was in accordance with the findings of Krailassiri et al., wherein he found that the hand-wrist radiographs of male subjects clearly differed from the standard plates/atlas more frequently than those of the female subjects.  He attributed these variations to environmental factors and racial differences. The skeletal age assessment in the total sample showed higher accuracy compared to the dental age assessment, suggesting that it is preferable to use skeletal age alone as a predictor for the younger age groups as stated by Kullman.  Though Greulich and Pyle's method of skeletal age assessment is used widely, the skeletal age is derived from only one part of the skeleton and that the hand wrist is not necessarily representative of the whole skeleton.
In the combined population when dental age was compared to chronological age, a significant accuracy could be elicited only in the group 3, 5, and 7 and when skeletal age was compared to chronological age, accuracy was noted in groups 1, 2, 5, 9, and 10. This shows that neither Demirjian's method of dental age estimation or Greulich and Plye's Atlas of skeletal age estimation showed any correlation in the entire population.
The variations in the results seen in the present study could be attributed to the fact that the original Demirjian study, which was carried out on the French-Canadian population, which may explain the difference in the race and ethnicity. The normal distribution of the differences between skeletal age, chronologic age, and dental age in this study could be caused by biologic variation. Other probable causes of differences are environmental factors such as a socio-economic status, malnutrition, and dietary habits that may vary in different populations.  Further, differences can be explained by natural variations between individuals in their rates of skeletal maturation, systemic error inherent in the method used to assess skeletal age, difference in sample size, method of age calculation, age groups, the age and sex distribution of the original study population, variation in the observer, and statistical methodology. It could also be due to the fact that the present sample size was relatively small and not fully comparable to material in reference study. Nystrom et al., suggested that differences in maturity exist not only between nations, but also between groups of children in a nation with a relatively homogenous population. Probably some mathematical alterations could be carried out to adapt the Demirjian's maturity scoring table to better suited the population of interest. 
| Conclusion|| |
It can be concluded from the present study that Demirjian's method of dental age estimation and Greulich and Pyle's method of skeletal age estimation showed accuracy in only certain age groups in Bangalore South zone children. A possible explanation for marked difference in the present study may be due to the differences in populations that is, differences in the genetic ancestry with the interbreeding of the populations. Therefore, environment and genetic makeup of an individual plays a considerable influence on maturation of dentition and skeleton and estimation of physiologic age. 
However, a further study with a large population is required in order to formulate a customised chart for Indian children in the field of both dental and skeletal age estimation.
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[Figure 1], [Figure 2]