Document Type : Original Article


1 Resident, Department of Orthodontics and Dentofacial Orthopaedics, AMC Dental College and Hospital, Ahmedabad, India

2 Dean and Head of the Department, Department of Orthodontics and Dentofacial Orthopaedics, AMC Dental College and Hospital, Ahmedabad, India

3 Lecturer, Department of Orthodontics and Dentofacial Orthopaedics, AMC Dental College and Hospital,Ahmedabad,India


Aim: To validate Pi angle with other sagittal discrepancy indicators like Beta angle, Yen angle and W angle in skeletal Class I, II and III patients, to correlate the Pi angle with the size and position of the mandible, and to evaluate the reliability of Dolphin imaging software.
Methods: One hundred fifty subjects were nominated based on the inclusion criteria and their lateral cephalograms were traced based on their ANB angle, they were placed into skeletal Class I, II and III groups. A-P discrepancy indicators and parameters of the size and position of the mandible were traced manually and digitally.
Results: Pi angle had 85% and 100% accuracy in identifying skeletal Class II and III groups, respectively. Parameters of the morphology of the mandible were found to have statistically significant correlation with Pi angle e.g., mandibular base length (-0.265), SNB (-0.408), articular angle (0.277), facial angle (-0.800), and Y axis (0.728), etc.  When data was compared between manual and digital tracing, there was no difference in the mean values of Pi angle (P=0.87), Beta angle (P=0.73), and Yen angle (P=0.64) between the two techniques, suggesting good accuracy of Dolphin imaging software.
Conclusion: The Pi angle could accurately differentiate the sample into skeletal Class I, II and III groups. A statistically significant correlation was determined between Pi angle and most of the parameters of the size and position of the mandible. It was found that the imaging software Dolphin 3D is dependable to the analysis of cephalometric variables, which are not available in the software.


Main Subjects

  1. Piombino P, Esposito E, Committeri U, Barone S, Arena A, Cataldo R, et al. Facial soft tissue thickness measurement method and relationship with BMI, age and sex. J Stomatol Oral Maxillofac Surg. 2023 Sep;124(4):101420.
  2. Aparna P, Kumar DN, Prasad M, Shamnur N, G AK, K R S, et al. Comparative assessment of sagittal skeletal discrepancy: a cephalometric study. J Clin Diagn Res JCDR. 2015 Apr;9(4):ZC38-41.
  3. CLEALL JF, BEGOLE EA. Diagnosis and Treatment of Class II Division 2 Malocclusion. Angle Orthod. 1982 Jan 1;52(1):38–60.
  4. Baik CY, Ververidou M. A new approach of assessing sagittal discrepancies: the Beta angle. Am J Orthod Dentofac Orthop Off Publ Am Assoc Orthod Its Const Soc Am Board Orthod. 2004 Jul;126(1):100–5.
  5. Bishnoi A, Kamat NV. New Method to Assess Sagittal Jaw Position: TWM and TWG Angles: A Cephalometric Study. J Indian Orthod Soc. 2023 Aug 24;03015742231188207.
  6. Neela PK, Mascarenhas R, Husain A. A new sagittal dysplasia indicator: the YEN angle. World J Orthod. 2009;10(2):147–51.
  7. Bhad WA, Nayak S, Doshi UH. A new approach of assessing sagittal dysplasia: the W angle. Eur J Orthod. 2013 Feb 1;35(1):66–70.
  8. Asudaria B, Jadav D, Srinivasulu D, Swamy D, Mothe D. Reliability of W-angle to assess sagittal skeletal dysplacia in Class I, Class II, Class III, patients: A Cephalometric study. Int J Appl Dent Sci. 2021 Jan 1;7:414–7.
  9. Kumar S, Valiathan A, Gautam P, Chakravarthy K, Jayaswal P. An evaluation of the Pi analysis in the assessment of anteroposterior jaw relationship. J Orthod. 2012 Dec;39(4):262–9.
  10. Naoumova J, Lindman R. A comparison of manual traced images and corresponding scanned radiographs digitally traced. Eur J Orthod. 2009 Jun;31(3):247–53.
  11. Polat-Ozsoy O, Gokcelik A, Toygar Memikoglu TU. Differences in cephalometric measurements: a comparison of digital versus hand-tracing methods. Eur J Orthod. 2009 Jun;31(3):254–9.
  12. Power G, Breckon J, Sherriff M, McDonald F. Dolphin Imaging Software: an analysis of the accuracy of cephalometric digitization and orthognathic prediction. Int J Oral Maxillofac Surg. 2005 Sep;34(6):619–26.
  13. Tsolakis IA, Tsolakis AI, Elshebiny T, Matthaios S, Palomo JM. Comparing a Fully Automated Cephalometric Tracing Method to a Manual Tracing Method for Orthodontic Diagnosis. J Clin Med. 2022 Nov 20;11(22):6854.
  14. Sanjeliwala A, Mehta F, Patel R, Bhattacharya A, Parekh H, Trivedi R. An Assessment and Comparison of Pi Analysis with Other Sagittal Discrepancy Indicators.
  15. Bohra S, Udeshi PS, Sinha SP, Saidath K, Shetty KP, Nayak UK. Predictability of pi angle and comparison with anb angle, w angle, yen angle, and beta angle in South Indian Population. J Indian Orthod Soc. 2018 Jan 1;52(1):22-8.
  16. Mehta PH, Bansal N, Singh G, Sunda S, Choudhary A, Chuchra A. Evaluation of Beta, Yen, and W Angle in Assessment of Anteroposterior Jaw Relationship in North Indian Population: A Cephalometric Study. J Mahatma Gandhi Univ Med Sci Technol. 2021 Aug 31;6(2):60–3.
  17. Soni G, Goel S, Gupta N, Kotecha T, Yadav N, Datar S. Comparative Evaluation of Yen Angle and W Angle with ANB Angle and Wits Appraisal for Predicting Sagittal Jaw Dysplasia. Eur J Mol Clin Med. 2021 Jan 15;8(2):2234–43.
  18. Paixão MB, Sobral MC, Vogel CJ, de Araujo TM. Comparative study between manual and digital cephalometric tracing using Dolphin Imaging software with lateral radiographs.
  19. Khan FA, Joneja P, Choudhary DS, Ahmed R, Tikekar S. Differentiation of evaluation of reliability of cephalometric analysis of cephalometrically diagnosed skeletal Class i malocclusion using readily available digital imaging software such as IMAGE J and ICY and traditional manual tracing. Indian J Dent Sci. 2021 Apr 1;13(2):80.