Context: Age estimation allows the identification of living individuals, dead victims and estimation of age in children using maxillofacial radiographs.
Aim: To compare age estimation by mandibular third molar developmental stages using modified Demirjian's method on OPG with age estimation by mandibular linear dimensions on lateral cephalogram.
Setting and design: A total of 200 randomly selected subjects (100 males and 100 females), with age range from 9 to 20 years, and 200 Digital Orthopantomograms and 200 Digital Lateral Cephalograms were utilized for the study.
Methods and material: Radiographs were taken with Kodak 8000C Digital Panoramic and Cephalometric machine operating at 60-90 kvp, with exposure time of 8-18 s at 2-15 mA, with an inbuilt magnification factor. A flat screen Compaq TFT-LCD monitor was used to view the OPG images. Linear mandibular dimensional measurements were made on each Digital Lateral Cephalogram using Trophy Dicom Software.
Statistical analysis used: Regression analysis and regression coefficient for establishing gender-specific equation were observed. Evaluation of results and statistical analysis was carried by using Student's 't' test. For all test, 'P' value of 0.05 or less was utilized for measuring the degree of significance. Intra-observer variability was detected using reliability analysis.
Results: The accuracy of age estimation by OPG was 93.8% and by lateral cephalogram was 79.7%.
Conclusion: The OPG analysis is more reliable than the cephalometric parameters.
Keywords: Age estimation; OPG; lateral cephalogram.