What is the SNA angle?

SNA: the angle between the sella/nasion plane and the nasion/A plane (normal value at the end of growth 82 ± 2°). This angle assesses the antero-posterior position of the maxilla relative to the upper cranial structures.

What are the advantages of cephalometric analysis?

A cephalometric analysis identifies defined anatomical landmarks on the film and measures the angular and linear relationships between them. This numerical assessment can provide detailed information on the relationship of skeletal, dental and soft tissue elements within the craniofacial region.

What can be measured by cephalometric tracing?

Cephalometric analysis can be performed to evaluate the cranial base, the relationship of the maxilla to the cranial base, the mandible’s size and position relative to the cranial base, the relationship between the maxilla and the mandible, the vertical dimension, maxillary and mandibular dentition, and soft tissue.

What is Steiners analysis?

The Steiner numerical analysis, which was developed in the 1950s (7–9) suggests a series of measurements not only to diagnose the problem but it also provides guidelines for treatment planning based on the pre- diction of changes that take place as a result of growth and/or orthodontic therapy.

What is the purpose of a cephalometric radiograph?

A cephalometric X-ray uses a specially adapted film holder mounted on a mechanical arm to capture images of your entire oral structure, including the nasal and sinus passageways to providing a comprehensive view of your jaw, mouth and head.

What are Cephalostat used for?

An instrument used to position the head for measurement and radiographic examination.

What is the correlation between SNA and SNB?

The correlation coefficient between the SNA and SNB angles is 0.7693 for males and 0.8220 for females, showing that these two measures of prognathism tend to increase and decrease together; opening (closing) one of the angles tends to open (close) the other.

Are the SNA and SNB angles useful in cephalometric analysis?

On the use of the SNA and SNB angles in cephalometric analyses Geoffrey F. Walker, B.D.S., and Charles J. Kowalski, Ph.D. Ann Arbor, Mi&. T he SNA and SNB angles have long been recognized as informative indicators of upper and lower facial prognathism and as useful guides in the diagnosis and treatment of malocclusion.

What is the normal range of the XNA and SNB angles?

He found a mean value of 81 degrees for the XNA angle (ranging from 78 to 84 degrees) and a mean value of 78 degrees (ranging from 75 to 81 degrees) for the SNB angle, and these figures have been generally accepted as representative of ormal variationdespite the fact that they are based on a small sample from a rather special population.

How does nasion position affect ANB and SNB?

Therefore, a posteriorly positioned nasion will increase ANB and more anterior positioned nasion can decrease ANB. In addition, short S–N plane or steeper S–N plane can also lead to greater numbers of SNA, SNB and ANB which may not reflex the true position of the jaws compare to the cranial base.