Can Orthopantomogram (OPG) be a Reliable Diagnostic Aid for Mandibular Measurements over Lateral Cephalogram: A Cross-Sectional Study

Aim: To find the reliability of OPG over Lateral Cephalogram for Mandibular Body Length, Mandibular Ramal Height and Total Mandibular Length.

Materials and Methods: Pre-treatment lateral cephalogram and orthopantomogram of 60 patient records within the age group of 12 to 25years were selected from the department of orthodontics and dentofacial orthopaedics, Noorul Islam College of dental science. The linear measurements of mandible such as Ramal height are measured from Condylion(Co) to Gonion(Go), total mandibular length from Condylion(Co) to Menton(Me)and body length from Gonion(Go) to Menton(Me).To improve the measurement accuracy, a digital vernier calliper will be used to measure and record the values.

Statistical Analysis: Study data obtained were entered into Microsoft Excel Software and exported to Statistical Package for Social Sciences (SPSS) Version 21, IBM Statistics, USA. Descriptive Statistics (Mean, Standard Deviation and Percentages) were obtained. Intergroup F quantitative analysis was done using the Independent-t-Test and Mann-Whitney Test with the level of significance set at 5% (p < 0.05 = Statistically Significant)

Results: The average age of the entire study group was 18.2 years. Average Mandibular body Length (ML), Ramal Height (RH), and Total Mandibular Length (TML) were traced on OPG with the Mean and Standard Deviation calculated at 87.14±4.14, 52.97±5.92 and 121.26±5.31 respectively. Whereas for the Lateral Cephalogram ML, RH, and TML were 70.16±4.70, 52.14±5.27, 107.31±5.80 respectively. Upon statistical analysis there was a significant mean difference between mandibular body length (ML) and total mandibular length (TML) with P value of 0.01 for both the parameters respectively. However, Ramal height (RH) showed no statistical difference in OPG and lateral cephalogram with P value of 0.41.

Conclusion: It can be concluded that Orthopantomogram (OPG) can be used as a reliable diagnostic aid for measuring Ramal Height compared to lateral cephalogram while OPG cannot be used as a reliable diagnostic aid for measuring mandibular body length and total mandibular length.