Age estimation using Orthopantomograph and Willems method in Chitwan population: an original study
Abstract: Utilization of age estimation has increased manifold in recent years. Various methods available for age estimation before the complete dentition has erupted and matured till the root closure stage include Nolla’s stages, Demirijan”s method, modified Demirijan’s method by Willems, Haavikko’s method. So, in this study we have tested that on Chitwan population of Nepal.
Materials and methods: 60 patients between the ages 6-16 were selected and digital orthopantomographs of each of the patients was taken and then Demerijian method was applied and age estimation done by Willems method. Whereas the chronolical age was known and the reliability of this method on this population checked.
Results : The study shows correlation between chronological age CA and estimated dental age DA in males – .965 while in females – .861 and it is statistically significant
Conclusion: There was an underestimation of age i.e. the dental age was found out to be less than the actual chronological age of the sample. This shows the dental growth lag in the Chitwan population. It was also found that when a comparison is done between the males and females it is found out that the females mature earlier than the males.
Keywords: OPG, Willems method, Chitwan population, Demirijans Method, Age Estimation, Forensic odontologist
Dental age estimation can serve as a very important tool in the identification of remains when done by a forensic odontologist.1 Forensic sciences deal with acquisition, documentation and evaluation of the evidence available so as to be presented in the court of trial.2 The word forensic has been derived from a Latin word Forensus and it relates to law and the evidence to be presented in court or a debate. In recent years there are many cases which need the age estimation to be done to find out the real age of the perpetrator of the crime so as to find out the law and the sections under which he falls as the laws and punishments are usually less for children before a certain age.3 These cases include burglary, rape, certain civil cases etc. Also when in case of murders or mass disasters, dead bodies or the skeletal remains are found age estimation can be done by dental methods so it is necessary that we find how reliably dental age is close to the chronological age.
Various methods available for age estimation before the complete dentition has erupted and matured till the root closure stage include Nolla’s stages, Demirijan”s method, modified Demirijan’s method by Willems, Haavikko’s method.4-8
Demerijan’s method was used to do age estimation in Caucasian studies but was found to overestimate the age so Willems8 has come forward with a modification which has been shown to be more accurate. So, in this study we are going to test that on Chitwan population of Nepal.
Materials and methods
This study was conducted in the department of Pedodontics, College of Medical sciences, Bharatpur, Chitwan, Nepal. The radiographs were done with the cooperation of the Oral medicine & Radiology Department.
The sample size was 60 patients between the ages 6-16 were taken and digital orthopantomographs of each of the patients was made by GENDEX ORTHORALIX 9200 following all the standard protocols and radiographs. These OPGs were done by a single radiographer to avoid any bias. Informed consent was taken from all the individuals taken in the study.
An inclusion criteria was selected and satisfied while taking the individuals for the study
(1) with non contributory medical history of systemic diseases or nutritional disorders (2) absence of any missing left mandibular teeth.
Whereas the exclusion criterion was taken to be (a) any serious psychiatric problems or endocrine diseases (b) history of extraction of permanent teeth, (c) Trauma to the face, (d) impacted or ankylosed teeth, (e) congenital developmental abnormalities.
All the 60 patients were examined clinically and the name, sex, birthdate and the date at which radiograph is taken was recorded by an individual not involved in doing the examination and performance of Willems Method on radiograph.
Then the digital panoramic radiographs were used to assess the calcification stages of the permanent teeth in left mandibular side from the central incisor to the second molar, using the Demirijan’s method modified by Willems. Using the Willems criterion, the age was calculated by summing up the various values and the dental age was calculated by this method.
The chronological age was calculated by subtracting the date of birth from the date on which the OPG is taken.
TABLE 1. The tooth formation stages as given by Demirijan and used in this study are as follows:
A- Calcified cusp tips that are not fused.
B- Calcified cusp tips that are fused with well-defined occlusal surface outline.
C- Complete formation of enamel at occlusal surface. Commencement of dentinal deposition.
D- Completion of crown formation upto cement enamel junction. Root formation is seen and pulp horns begin to differentiate.
E- Pulp horns and pulp chamber are more differentiated. Root length is less than crown length. Radicular bifurcation is visible in molars.
F- Funnel shaped apex is seen. Crown length is equal and greater than root length.
G- Root canal walls are parallel and the apical ends are still open.
H- Apical ends are closed and uniform periodontal ligament space is seen around the tooth.
TABLE 2 8Developmental tooth stages with corresponding age scores expressed directly in years for each of the seven left mandibular teeth in boys and girls
This study took the sample size to be 60 individuals amongst which 36 were females and 24 males. The mean chronological age of 60 samples – 13.36, while the mean estimated age of 60 samples-13.7 (TABLE 3)
TABLE 3. MEAN CHRONOLOGICAL AGE AND MEAN ESTIMATED AGE OF 60SAMPLES
1. CHRONOLOGICAL AGE.
The difference that have been found out between the actual chronological age and the estimated dental age is statistically significant with a p value <0.05. TABLE 4. Mean Chronological Age And Mean Estimated Age Of Males And Females GENDER N MEAN STANDARD DEVIATION CORELATION P-VALUE MALE CHRONOLOGICAL AGE 24 13.14 2.10 0.965 0.000 ESTIMATED AGE 24 13.83 1.63 FEMALE CHRONOLOGICAL AGE 36 13.56 1.72 0.861 0.000 ESTIMATED AGE 36 13.82 2.12 The correlation between chronological age CA and estimated dental age DA in males - .965 while in females - .861 and it is statistically significant p value < 0.05 DISCUSSION: Age estimation has become an indispensible part of forensics these days because of its role in many different types of crimes and in times of mass disasters like tsunami. Forensic odontologists use the dentition to estimate the age of the deceased. Though there are many different methods for age estimation in adults like amino acid estimation mainly d-amino acid estimation, Gustafson's method, dental cementum increment analysis etc but developing teeth can be used to give a dental age estimation by seeing the developing teeth. Ages 6 years till 12-13 years comprises the mixed dentition period when the teeth are developing and thus by seeing the mineralization of these teeth, the age estimation techniques have been used.9 Digital orthopantomograms are a reliable source where a single radiograph can be effectively used to see the developmental status of whole dentition and use it for the purpose of dental age estimation. Certain problems like systemic diseases such as endocrine problems which can lead to delay in the eruption or mineralization of teeth have been excluded from the studies. Also, patients were asked for a history of previous trauma in the region which could have impeded the growth in some way. The methods presently available for the age estimation seeing The various methods of age assessment using the tooth development show an ethnic variation In 2001, Willems et al.,evaluated the accuracy of Demirjian's method on a Belgian population and they concluded that no two individuals grow and develop at the same rate.8 So it can be concluded that there are variation in tooth development amongst populations and ethnic groups.10-11 So, this study was performed to compare the DA assessment in children of Chitwan district in Nepal. In this study it was found out there was an underestimation of age i.e. the dental age was found out to be less than the actual chronological age of the sample.12 This shows the dental growth lag in the Nepalese population. It was also found that when a comparison is done between the males and females it is found out that the females mature earlier than the males. 13-15 We should always keep in mind that till date there is no method of estimation of age which is totally accurate since the development varies between individuals naturally. DA is not same for all the people in the same chronological age. References 1. Bagic IC, Sever N, Brkic H, Kern J. Dental age estimation in children using orthopantomograms. Acta Stomatol Croat2008;42:11-8. 2. Willems G. A review of the most commonly used dental age estimation techniques. J Forensic Odontostomatol 2001;19:9-17. 3. Lewis AB, Garn SM. The relationship between tooth formation and other maturational factors. Angle Orthod 1960;30:70-7. 4. Koshy S, Tandon S. Dental age assessment: the applicability of Demirjian's method in South Indian children. Forensic Sci Int 1998;94(1-2):73-85. 5. Liversidge HM , Speechly T , Hector MP. Dental maturation in British children: are Demirjian's standards applicable? Int J Paediatr Dent 1999;9(4):263-269. 6. Frucht S , Schnegelsberg C , Schulte-Mönting J , Rose E , Jonas I. Dental age in southwest Germany: a radiographic study. J Orofac Orthop 2000;61(5):318-329. 7. 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(2):54-62. 8. Willems G, Olmen AV, Spiessens B, Carels C. Dental age estimation in Belgian children: Demirjian's technique revisited. J Forensic Sci 2001;46(4):893-895 9. Singh N, Grover N, Puri N, Singh S, Arora S. Age estimation from physiological changes of teeth: A reliable age marker? Journal of Forensic Dental Sciences. 2014;6(2):113-121. doi:10.4103/0975-1475.132541. 10. Asaba SA, Noorb SNFM . The accuracy of Demirjian's method in dental age estimation of Malay children. Singapore Dent J 2011;32(1):19-27. 11. Grover S. Estimation of dental age and its comparison with chronological age: accuracy of two radiographic methods. Med Sci Law January 2012;52(1):32-35. 12. Maber M, Liversidge HM, Hector MP. Accuracy of age estimation of radiographic methods using developing teeth. Forensic Sci Int 2006;15(l):68-73. 13. Maber M, Liversidge HM, Hector MP. Accuracy of age estimation of radiographic methods using developing teeth. Forensic Sci Int 2006;159 Suppl 1:S68?73. 14. Liversidge HM. Dental age revisited. In: Irish JD, ditors. Technique and Application in Dental Anthropology. Cambridge: Cambridge University Press; 2008. p. 234?52. 15. Cameriere R, Ferrante L, Liversidge HM, Prieto JL, Brkic H. Accuracy of age estimation in children using radiograph of developing teeth. Forensic Sci Int 2008;176:173?7