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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 26  |  Issue : 3  |  Page : 279-286

Dental age estimation by Demirjian's and Nolla's method: A comparative study among children attending a dental college in Lucknow (UP)


1 Department of Oral Medicine and Radiology, Saraswati Dental College and Hospital, Lucknow, Uttar Pradesh, India
2 Department of Oral Medicine and Radiology, Babu Banarasi Das College of Dental Sciences, Lucknow, Uttar Pradesh, India
3 Department of Oral Medicine and Radiology, Rungta College of Dental Sciences and Research, Bhilai, Chattisgarh, India
4 Department of Dentistry, SEGi University, Selangor, Malaysia

Date of Submission06-Jul-2014
Date of Acceptance23-Sep-2014
Date of Web Publication19-Nov-2014

Correspondence Address:
Shruti Sinha
Department of Oral Medicine and Radiology, Saraswati Dental College and Hospital, Faizabad Road, Tiwari Ganj, Lucknow, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-1363.145005

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   Abstract 

Introduction: Estimation of age is an important aspect of forensic science. The assessment of age is useful in forensic odontology and in treatments plans of orthodontic and pedodontic patients. Aims and Objectives: The aim of the study was to determine dental age from orthopantomograph using Demirjian's method and Nolla's method. It was also to evaluate the interrelationship between chronological and dental age according to both these methods and to evaluate which technique was better. Materials and Methods: The study was conducted in the Department of Oral Medicine and Radiology of Babu Banarasi Das College of Dental Sciences (UP, Northern India). A total of 300 subjects (150 girls and 150 boys) of age group from 6 years to 15 years were enrolled. These subjects were grouped by a difference of 1 year into 10 groups (each group comprised of 30 subjects: 15 males and 15 females). For every individual included in the study a panoramic radiograph was taken, with standard parameters and adequate protective measures. Results: The results imply that Demirjian's method is applicable to all age groups and for both genders with better accuracy than Nolla's method, which had a limited utility in younger age group. Thus Demirjian's method is a better method when compared to Nolla's method in Northern Indian population.

Keywords: Age estimation, Demirjian′s method, forensic odontology, forensic research, forensic science, Nolla′s method


How to cite this article:
Sinha S, Umapathy D, Shashikanth MC, Misra N, Mehra A, Singh AK. Dental age estimation by Demirjian's and Nolla's method: A comparative study among children attending a dental college in Lucknow (UP) . J Indian Acad Oral Med Radiol 2014;26:279-86

How to cite this URL:
Sinha S, Umapathy D, Shashikanth MC, Misra N, Mehra A, Singh AK. Dental age estimation by Demirjian's and Nolla's method: A comparative study among children attending a dental college in Lucknow (UP) . J Indian Acad Oral Med Radiol [serial online] 2014 [cited 2019 Mar 26];26:279-86. Available from: http://www.jiaomr.in/text.asp?2014/26/3/279/145005


   Introduction Top


Forensic odontology is a new science that has developed as a separate speciality. [1] It utilizes the knowledge of a dentist to serve the judicial system. Estimation of age is an important aspect of forensic research. The assessment of age is useful in planning treatment of orthodontic and pedodontic patients, and in forensic medicine and forensic odontology. Its use is increasing in both civil and criminal matters and is also helping in the identification of age at death of a dead individual in mass disasters and natural calamities. Age estimation also provides valuable information when the birth date is not available, as in case of illegal immigrants. Also the chronological age of living people is important in cases of employment and marriage. [2] Skeletal, dental, and psychological methods allow an approximate assessment of age and can be applied singly or in combination to assess the degree of physical maturity of individuals.

Various radiographic methods, depending on tooth calcification, have been reported. Among them the most widely used dental maturity method was described by Demirjian, et al. [3] in 1973, on French-Canadian children. It is based on the development of seven left permanent mandibular teeth. Its maturity scoring system provides for a universal application. [3] Nolla's technique (1960), is considered to be one of the methods for assessing dental calcification in a wider age range. It utilizes maturation of teeth for age assessment. [4]

Various studies for assessing the dental age have been conducted on the Western population, whereas, only a few studies have been reported in the Indian population. Thus, the present study was conducted to determine the age of children in Northern India based on both the Demirjian's method and Nolla's method.


   Aims and Objectives Top


The aim of the study is to determine the dental age from an orthopantomograph using the Demirjian's method and the Nolla's method and to evaluate the interrelationship between the chronological and dental age according to both these methods; the aim was also to evaluate which technique was better.


   Materials and Methods Top


The study was conducted in the Department of Oral Medicine and Radiology of the Babu Banarasi Das College of Dental Sciences (UP, Northern India). Ethical clearance for the study was obtained from the Institutional Ethical Committee. A total of 300 subjects (150 girls and 150 boys) between the age group of six and fifteen years were enrolled. These subjects were grouped by a difference of one year into 10 groups (each group comprised of 30 subjects: 15 males and 15 females).

For examination of the patient, a dental chair with illuminating facility, a pair of sterile disposable gloves, a mouth mask, and a stainless steel kidney tray containing a mouth mirror, straight probe, tweezer, and explorer were used.

For radiographic procedures, a panoramic machine (Rotagraph plus, panoramic and cephalometric machine, VILLA SISTEMI MEDICALI, 2002, Made in Italy) with kVp of 70 (adult), −65 (children), and standard 10 mA provided with a total filtration of 2.5 mm aluminum, a 5 × 12 inch rigid, curved aluminum cassette with green light-sensitive intensifying screens (Kg4 Kiran), 5 × 12 inch Kodak T-MAT G/RA green light-sensitive panoramic dental films made in USA by Eastman Kodak, Rochester, New York, and lead aprons were used.

For interpretation of radiographs, a radiographic view box, opaque material (thick black chart paper) cut to fit the entire view box, leaving an opening for one film and a vernier caliper were used.

Examination of the patient

The study subjects were made to sit comfortably in a dental chair. The patients were examined under artificial illumination. A clinical examination was carried out. Each patient and their parents/guardians were informed about the protocol and were given appropriate instructions. An informed consent was obtained before the start of procedure and appropriate instructions were given to each patient. The criteria used for subject selection were:

Inclusion criteria

The inclusion criteria were, a full complement of mandibular permanent teeth (erupted or unerupted); physically healthy and well-nourished subjects; nonsyndromic children; patients with normal growth and development; no history of surgical or medical diseases that could affect the presence and development of mandibular permanent teeth; and radiographs of diagnostic quality.

Exclusion criteria

The exclusion criteria were, an unclear orthopantomograph or image deformity affecting mandibular permanent tooth visualization; patients with systemic disease; congenital anomalies (oral maxillofacial anomalies, such as, cleft lip and cleft palate); dental abnormalities (aplasia, hypodontia, hyperdontia, supernumerary teeth, impaction, missing, transposition of teeth, and malocclusion); any permanent teeth extractions; history of trauma or injury to face; and gross dental pathology.

For every individual included in the study, a panoramic radiograph (OPG) was taken with standard parameters and adequate protective measures [Figure 1]. The interpretation of the panoramic radiographs was done using an x-ray radiographic view box. The OPGs were analyzed for the developmental stages of teeth according to the criteria given by both the Demirjian's method and the Nolla's method [Figure 2]. [3],[4],[5]
Figurre 1: Patient positioned in orthopantomogram

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Figure 2: Radiographic analysis using orthopantomograph

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Demirjian's method

Seven teeth present on the left side of the mandible were assessed. Eight stages of development (A to H), from calcification of the tip of the cusp to the closure of the apex, were determined for each tooth by precisely following the written and pictorial criteria set out by Demirjian. The developmental stage of each tooth was converted into a score using the conversion table given by Demirjian for boys and girls. The scores of all the seven teeth were added together to give the total maturity score. After the maturity score was calculated, it was converted to the dental age by referring to the table given by Demirjian, to obtain the dental age. [3]

Nolla's method

Seven teeth present on the left side of the mandible were taken into consideration. Nolla had divided the stages of dental development into ten stages through each of which every tooth passed. These stages were determined for all the teeth. Each stage also had a numerical score. The scores were totaled to give a combined 'sum of stages' score, that was then divided by the number of teeth taken into consideration to give the dental age. [5]

The chronological age was determined from the date of birth and recorded as years and months. All the relevant data were entered in the proforma. It was then sorted, tabulated, and statistically analyzed to draw a conclusion.

Statistical analysis

The statistical analysis was done using the SPSS (Statistical Package for Social Sciences) Version 15.0 statistical analysis software. The values were represented in Number (%) and Mean ± SD. The paired t-test and Chi square test were applied and the level of significance was calculated.


   Results Top


A total of 300 subjects (150 girls and 150 boys) in the age group of six to fifteen years were enrolled. These subjects were grouped by a difference of one year into 10 groups (each group comprised of 30 subjects: 15 males and 15 females).

The overall mean age of the subjects was 10.94 ± 2.88 years. The overall mean age of males was 10.93 ± 2.88 years, whereas, the overall mean age of females was 10.95 ± 2.90 years. Among males, in all the age groups, the mean age was below midpoint, except for the age groups of seven years and fifteen years, where it was slightly above the midpoint level. Among females, in all the age groups, the mean age was below midpoint, except for the age groups of 10, 11, 12, and 14 years, where it was slightly above the midpoint level. Overall, the mean age was below the midpoint for all the age groups.

When Demirjian's method for both males and females was applied, it showed that the mean chronological age was 10.94 ± 2.88 and the mean estimated age was 10.92 ± 2.84. A significant difference in chronological age and estimated age was observed in the age groups 6, 7, 10, 11, and 13 years (P < 0.05). The maximum mean age difference between the chronological age and the estimated age was 0.24 ± 0.43 years for the 13 year age group, which was underestimated [Table 1], [Graph 1] [Additional file 1].
Table 1: Combined comparison of mean chronological age and mean estimated age in both males and females (Demirjian's method)

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The combined range of variation (in months) between the chronological age and estimated age in both males and females when the Demirjian's method was used showed that the majority of subjects in all the age groups, that is, 230 (76.7%), had ≤3 months difference between the chronological age and estimated age. In the younger age groups (6-12 years) the difference of ≥6 months was observed, in the range of 0 to 10% only. However, in subjects above 12 years, the difference of ≥6 months ranged from 3.3 to 23.3%. Statistically, there was a significant association between the age group and extent of difference between the chronological age and estimated age (P = 0.002) [Table 2], [Graph 2] [Additional file 2].
Table 2: Combined range of variation (in months) between chronological age and estimated age in both males and females (Demirjian's method)

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Using the Nolla's method for both males and females, the mean chronological age was 10.94 ± 2.88 years and the mean estimated age was 9.98 ± 2.04 years. No significant difference between the chronological age and estimated age was observed up to the age group of nine years; however, from the age group of nine years onward, the mean estimated age was significantly lower as compared to the chronological age (P < 0.001). In the 15-year age group, the mean difference between the estimated and chronological age was 3.193 ± 0.546 years [Table 3], [Graph 3] [Additional file 3].
Table 3: Combined comparison of mean chronological age and mean estimated age in both males and females (Nolla's method)

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The combined range of variation in months between the chronological age and estimated age in both males and females, using the Nolla's method, showed that the majority of subjects had three or more months of difference between the chronological age and estimated age, except the subjects in the age group of eight years. With increasing age, the difference between chronological age and estimated age was found to be increasing. For age groups of 13 years and above, all the subjects had a difference of ≥6 months between the chronological age and estimated age. Statistically, there was a significant association between the age group and extent of difference between the chronological age and estimated age (P = 0.002) [Table 4], [Graph 4] [Additional file 4].
Table 4: Combined range of variation (in months) between chronological age and estimated age in both males and females (Nolla's method)

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The proportion of subjects with range of variation between the chronological age and estimated age within three months was significantly higher in the Demirjian's method, that is, 230 (76.7%) as compared to that in the Nolla's method, which was 86 (28.7%). The proportion of subjects with range of variation between chronological age and estimated age >6 months was significantly higher in the Nolla's method, that is, 181 (60.3%) as compared to that in the Demirjian's method, which was, 17 (5.7%) (P < 0.001) [Table 5], [Graph 5] [Additional file 5].
Table 5: Combined comparative predictive accuracy of Demirjian's
and Nolla's methods


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On combined comparison of the mean difference (of estimated age) from chronological age, using Demirjian's and Nolla's methods (males and females) for younger age groups (up to nine years of age), there was no significant difference between the two methods; however, for older age groups (≥10 years), the difference between the two methods was statistically significant. Overall too, there was a significant difference between the two methods (P < 0.05) [Table 6], [Graph 6] [Additional file 6].
Table 6: Combined comparison of mean difference from chronological age for males and females between Demirjian's and Nolla's methods

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   Discussion Top


Age determination pertains to many fields including treatment planning in orthodontics and pediatric dentistry. It is also useful to identify individuals who provide inaccurate details of age, as in case of illegal immigrants, or a corpse with an unknown identity.

The aim of an ideal age estimation method is to arrive at an age as close to the chronological age as possible. Various age estimation methods have been tested and reported in literature on different ethnic populations. Only few studies on the Indian population have been reported. [6],[7] Thus, the need was felt, to determine the age using Demirjian's and Nolla's methods on the Lucknow population.

Demirjian's method is one of the simplest, most practical, and widely employed methods to predict age and maturation, as it comprises of clearly defined changes in shape that do not require speculative estimation. [2],[3],[8] Nolla's method is based on 10 stages of tooth development. It has been the method of choice over the years. It gives the possibility of scoring the degree of tooth development. [9]

Tooth formation stages are better than emergence of tooth for age estimation, as tooth emergence can be disturbed by various factors such as infection or extraction, crowding, and ankylosis. Therefore, determination of the exact time is very difficult, whereas, calcification is a continuous process; hence, the age can be estimated using a radiographic study of this calcification process. [6]

In the present study, panoramic radiographs were made by using standard parameters with adequate protective measures. They were analyzed for the developmental stages of teeth according to the criteria given by both the Demirjian's and Nolla's methods.

Panoramic images were taken as they are more comfortable for the subjects who do not tolerate intraoral procedures well (young nervous children). Also the subjects are exposed to less radiation in comparison to a full-mouth intraoral periapical radiographic (IOPA) series and there is less distortion in the mandibular region. [2]

Although there is 3 to 10% enlargement of the mandible, this is not a serious drawback, because the rating system we have used in our study is based on shape criteria and relative values rather than on the absolute length.

In the present study, the overall mean age of males was 10.93 ± 2.88 years, whereas, the overall mean age of females was 10.95 ± 2.90 years.

Demirjian's method

In combined population (males and females), the mean chronological age was 10.94 ± 2.88 years and the mean estimated age was 10.92 ± 2.84 years.

The present study showed no significant differences between the actual and estimated age. Similar results were seen in a study done by Hagg and Matson in 1985, who found high accuracy and precision in the methods of age estimation on Swedish children. [10] The results in the studies done by Farah, et al., in 1995, [11] and Nykanen, et al., in 1998, [12] were in accordance with the present study. Similar results were seen in a study done by Liversidge, et al. in 1999, in which the mean (±SD) advancement in girls was 0.51 ± 0.79 years and in boys was 0.73 ± 0.73 years, which was not significant, and thus, the Demirjian's method was found to be an accurate method. [13]

However, the observations of the present study are not in agreement with the study by Koshy S and Tandon S of 1998, wherein, an overestimation of age in South Indian children was observed. [7] Prabhakar et al., in 2002, [14] Hegde and Sood, in 2002, [15] Mani et al., in 2008 [16] , and Bagic et al., in 2008 [2] obtained a dental age that was found to be higher than the chronological age in both males and females.

Overestimation of age by the Demirjian's method may probably be because of cultural and ethnic differences between the populations. Also, it may be because of environmental factors such as socioeconomic status, nutrition, and dietary habits that vary in different population groups.

Nolla's method

In a combined population (males and females), the mean chronological age was 10.94 ± 2.88 years and the mean estimated age was 9.98 ± 2.04 years.

No significant difference between the chronological age and estimated age was observed up to the age of nine years; however, from the age of nine years onward, the mean estimated age was significantly lower as compared to chronological age (P < 0.001). In the present study, Nolla's method showed a significant difference between the actual age and estimated age overall as well as for both the genders separately, mainly in subjects aged nine years or above. This was in agreement with the study done by Briffa et al., in 2005, which showed that the Nolla's method overestimated the chronological age by up to six months in boys and underestimated the chronological age up to one year in girls. [17] In the present study, Nolla's method showed underestimation of age in the group of nine years and above. The differences in the results may be because of differences in the quality of the reference material, reliability of the measurement method, geographical factors, nutrition, socioeconomic levels, urbanization, and a wide biological variability in dental development among individuals. [17]

The comparison between both the methods for both the genders in a majority of the subjects in Demirjian's method had a variation of <3 months, whereas, in Nolla's method, the majority of subjects showed a variation of >6 months between the actual age and estimated age. However, this variation in Nolla's method was observed in the age group of nine years and above. The possible reason could be that the varying mineralization time of all the teeth is not covered in Nolla's method and also it is an ordinal scale; therefore, it could be assumed that the quantitative amounts of tooth material laid down during one stage were the same during another.

Our results were in agreement with the results of the study done by Maber et al., in 2006, in which they showed that the Demirjian's method was found to be the most accurate method for estimating age in the given sample when compared with the Nolla's method. [18] However, it was not in agreement with the results of the study done by Rai B and Anand SC, in 2006, in which they concluded that the Nolla's method yielded a mean estimation of 0.07 for boys and 0.08 for girls, which showed a significant difference from the chronological age, whereas, Demirjian's method was found to overestimate the age, with a mean accuracy of 0.25 years for boys and 0.24 years for girls. Thus, they concluded that the Nolla's method was a more accurate method as compared to the Demirjian's method. [9]


   Conclusion Top


The present results imply that the Demirjian's method is applicable to all the age groups and in both the genders, with a better accuracy than the Nolla's method, which had a limited utility in the younger age group only. Thus, it can be concluded that Demirjian's method is a better method when compared to Nolla's method in North Indian population. This variation may be because of the cultural and ethnic difference between populations involved in Demirjian's and Nolla's study. [6] The results of the present study confirm the validity of the dental age estimation methods. However, further research should be aimed at, with a larger sample to further acknowledge the accuracy of Demirjian's method and Nolla's method.


   Acknowledgment Top


The authors thank the faculty, the nonteaching staff, and radiology technicians of the Department of Oral Medicine and Radiology, Babu Banarasi Das College of Dental Sciences, Faizabad Road, Lucknow, Uttar Pradesh, India.

 
   References Top

1.Shafer WG, Hine MK, Levy BM. A Textbook of Oral Pathology. 5 th ed. Pennsylvania: WB Saunders; 2003. p. 1196-227.  Back to cited text no. 1
    
2.Bagiæ IC, Sever N, Brkiæ H, Kern J. Dental age estimation in children using orthopantomograms. Acta Stomatol Croat 2008;42:11-8.  Back to cited text no. 2
    
3.Demirjian A, Goldstein H, Tanner JM. A new system of dental age assessment. Hum Biol 1973;45:211-27.  Back to cited text no. 3
    
4.El-Yazeed MA, Zeid WA, Tawfik W. Dental maturation assessment by Nolla's technique on a group of Egyptian children. Aust J Basic Appl Sci 2008;2:1418-24.  Back to cited text no. 4
    
5.Ash MM. Wheeler's Dental Anatomy, Physiology and Occlusion. 6 th ed. Philadelphia: WB Saunders Publishing; 1996. p. 23-39.  Back to cited text no. 5
    
6.Warhekar AM, Wanjari PV, Phulambrikar T. Correlation of radiographic and chronological age in human by using Demirjian's method: A radiographic study. J Indian Acad Oral Med Radiol 2011;23:1-4.  Back to cited text no. 6
    
7.Koshy S, Tandon S. Dental age assessment: The applicability of Demirjian's method in south Indian children. Forensic Sci Int 1998;94:73-85.  Back to cited text no. 7
    
8.Liversidge HM, Chaillet N, Mörnstad H, Nyström M, Rowlings K, Taylor J, et al. Timing of Demirjian's tooth formation stages. Ann Hum Biol 2006;33:454-70.  Back to cited text no. 8
    
9.Rai B, Anand SC. Tooth development: An accuracy of age estimation of radiographic methods. World J Med Sci 2006;1:130-2.  Back to cited text no. 9
    
10.Hägg U, Matsson L. Dental maturity as an indicator of chronological age: The accuracy and precision of three methods. Eur J Orthod 1985;7:25-34.  Back to cited text no. 10
    
11.Farah CS, Booth DR, Knott SC. Dental maturity of children in Perth, Western Australia, and its application in forensic age estimation. J Clin Forensic Med 1999;6:14-8.  Back to cited text no. 11
    
12.Nykänen R, Espeland L, Kvaal SI, Krogstad O. Validity of the Demirjian method for dental age estimation when applied to Norwegian children. Acta Odontol Scand 1998;56:238-44.  Back to cited text no. 12
    
13.Liversidge HM. Dental maturation of 18 th and 19 th century British children using Demirjian's method. Int J Paediatr Dent 1999;9:111-5.  Back to cited text no. 13
    
14.Prabhakar AR, Panda AK, Raju OS. Applicability of Demirjian's method of age assessment in children of Davangere. J Indian Soc Pedod Prev Dent 2002;20:54-62.  Back to cited text no. 14
[PUBMED]    
15.Hegde RJ, Sood PB. Dental maturity as an indicator of chronological age: Radiographic evaluation of dental age in 6 to 13 years children of Belgaum using Demirjian methods. J Indian Soc Pedod Prev Dent 2002;20:132-8.  Back to cited text no. 15
[PUBMED]    
16.Mani SA, Naing L, John J, Samsudin AR. Comparison of two methods of dental age estimation in 7-15-year-old Malays. Int J Paediatr Dent 2008;18:380-8.  Back to cited text no. 16
    
17.Briffa K, Dougall NB, Galea J, Misfud D, Camilleri S. Chronologic and dental ages of Maltese school children: A pilot study. Malta Medical Journal 2005;17:31-5.  Back to cited text no. 17
    
18.Maber M, Liversidge HM, Hector MP. Accuracy of age estimation of radiographic methods using developing teeth. Forensic SciInt 2006;159(Suppl 1):S68-73.  Back to cited text no. 18
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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