A study of relationship between mandibular plane and the most inferior point of posterior cranial fossa in patients with normal facial height .

Document Type : original article

Authors

1 Assistant Professor, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Iran

2 Dentist

Abstract

Introduction: ِAmong several cephalometric analyses used in orthodontics, none of them could present all diagnostic and interpretative featwres. The aim of this study is to apply a simple and convenient approach which could enable the orthodontists to gain maximum information from it .
Materials and Methods: Cephalograms of 58 adults patient (40 femals and 18 males) with mean age of 15 years and 4 months, were used for analysis. After tracing , the  relationship between mandibular plane and the most inferior point of posterior cranial fossa was assessed.
Results: The data revealed that:
- SNA and SNB were less than norms which was not significant.
- In patients with normal facial height, extention of mandibular plane lay lower to posterior cranial fossa and the mean distance was 6.84 mm.
- Mp-Ar-N Angle was 42º to 55º (49 ± 6) that was 2º less than Norms.
Conclusion: Extention of mandibular plane to  posterior cranial fossa or lower, shows that there is a failure in vertical growth.

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