Reliability of Dhaval–Rohan angle for assessment of vertical dysplasia

Abstract

Objectives Assessment of Dhaval–Rohan (DR) angle as a vertical dysplasia indicator. Materials and methods One hundred and forty lateral cephalometric radiographs of Egyptian orthodontic patients of both sexes with age ranging from 16 to 28 years old, collected from the record files of patients admitted for treatment of various malocclusions. The enrolled cases were subdivided based on SN/MP angle, FH/MP angle, Y-axis/FH angle, gonial angle, and LAFH/TAFH, into high angle (hyperdivergent), low angle (hypodivergent), and average (normodivergent) cases according to Aboul-Azm and colleagues. Each case had to have a minimum of three of the five parameters indicating its pattern of growth, DR angle was constructed by using three skeletal points; C (center of condyle where the angle located), M (center of premaxilla), and G (center of symphysis of mandible), the measured data were led to the computer and statistically analyzed using the Statistical Package for Social Sciences software, version 24. Quantitative data were expressed using range (minimum and maximum), mean, and SD. Significance of the obtained results was judged at P value less than 0.05. Results There is a strong correlation between the conventional parameters and DR angle. The cutoff point of the DR angle below 28° indicates a horizontal growth pattern, between 28.5 and 32.5° indicates an average growth pattern, and above 32.5° indicates a vertical skeletal growth pattern. Conclusion The DR angle is a reliable parameter in assessing vertical skeletal growth pattern with minimal cephalometric landmarks that easily and accurately located.