Abstract

Introduction: Frankfort horizontal (FH) plane and Sella-Nasion (SN) plane are commonly used reference planes in orthodontic cephalometry. Any variation in this angulation from its accepted 7 degree can affect the cephalometric diagnosis. The objective of the study was to determine an average FH-SN angle among patients seeking orthodontic treatment.

Materials and Methods: One hundred lateral cephalograms were obtained from the records of patients who came for orthodontic treatment in Orthodontics and Dentofacial Orthopaedic Unit. Cephalometric tracing was done on acetate tracing paper of 0.004 inch thick using 3H pencil of 0.5 mm. Mean and standard deviation of FH-SN angle of the samples was calculated. One way analysis of variance and independent-samples t-test were used for assessing the relationship between dependent and independent variables at P-value of 0.05.

Results: Average FH-SN angle was found to be 7.57° (SD = 2.57°). FH-SN angle was found to be 7.97° (SD = 2.66°) in Class I subjects, 7.44° (SD = 3.10°) in Class II subjects and 7.25° (SD = 2.45°) in Class III subjects. FH-SN angle did not vary significantly among different sagittal skeletal patterns (P value > 0.05). There was no gender variation of FH-SN angle (P value > 0.05). The angle between the posterior vertical maxillary plane and Frankfort plane (PM-FH) was found to be 102.94° (SD = 5.10°) in Class I subjects, 102.57° (SD = 4.64°) in Class II subjects and 103.62° (SD = 4.23°) in Class III subjects. Similarly, the angle between the posterior vertical maxillary plane and sella-nasion plane (PM-SN) was found to be 110.91° (SD = 6.07°) in Class I subjects, 110.01° (SD = 5.07°) in Class II subjects and 110.88° (SD = 4.30°) in Class III subjects.

Conclusion: The average FH-SN angle was found to be 7.57° (SD = 2.57°). There was no variation in FH-SN angle in different sagittal skeletal patterns. FH-SN angle did not exhibit sexual dimorphism. The use of the PM line in evaluating the positioning of the horizontal FH and SN planes can help us establish which of the two planes is more reliable.

Keywords: Cephalometric Study; FH-SN Angle; Variation; Sagittal Skeletal Patterns; Posterior Vertical Maxillary Plane

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Citation

Citation: Avinash Chaudhary., et al. “A Cephalometric Study of FH-SN Angle in Different Sagittal Skeletal Patterns among Patients Seeking Orthodontic Treatment". Acta Scientific Dental Sciences 4.11 (2020): 115-119.

Copyright

Copyright: © 2020 Avinash Chaudhary., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.