Charles J. Burstone developed a popularly used cephalometric analysis in 1978 that’s still being commonly used by orthodontists today for patients who require Orthognathic surgery. In this analysis they use landmarks and measurements that can be altered through several common surgical procedures. The Burstone analysis can also be known as COGS (Cephalometrics for Orthognathic Surgery).
The COGS system carefully describes the patient’s horizontal and vertical positions of their facial bones by using constant coordinate systems:
- Size of the bone: represented by direct linear measurements
- Shape of the bone: represented by angular measurements
The chosen landmarks and measurements are chosen because they can be easily altered by various surgical procedures. The Burstone analysis includes all of the facial bones along with a cranial base as a reference. Once the critical facial skeletal components have been measured, the orthodontist can use these measurements in a mock surgery setting. Through this systemized approach all of the measurements can then be computerized.
Skeletal and Dental Analysis
Horizontal Skeletal Analysis
When analyzing the horizontal skeletal profile analysis a few simple measurements should be made on the skeletal profile in order to assess the amount of discrepancy among the anteroposterior direction. This is called the Horizontal Skeletal Profile Analysis simply because of all of the measurements in this set of analysis and their make up parallel to the horizontal profile.
The angle of convexity is the angle formed between N-A and A-Pg, the standard value in males ranges from 3.90 to 6.40, and 2.60 and 5.10 in females. In this case, a positive angle represents convex profiles while negative angles are an indication of concave profiles. This measurement describes the position of apical base of the maxilla in relation to the nasion. It’s measured by taking N perpendicular to A, parallel to HP. The horizontal distance is dropped from N and measured from point A.
Vertical Skeletal Analysis
The vertical skeletal discrepancy may be reflective of an anterior, posterior, or complex dysplasia of the face. This discrepancy is divided into two main components: an anterior component and a posterior component.
To measure this discrepancy, the N-ANS perpendicular to HP, the orthodontist must measure the distance between N and ANS measured perpendicularly to HP. This measurement will give the facial height for the middle third of the patient’s face. The standard value for men ranges between 51.5 to 57.9, whereas for women the standard value ranges from 47.6 to 52.4. Any slight increase or decrease in this value can indicate an increase or decrease in the middle third facial height respectively.
The Burstone Cephalometric Analysis is just but one step in a diagnosis and treatment planning process for surgical cases. This analysis can give the clinician or orthodontist greater insight into the quantitative nature of the skeletodental and soft tissue dysplasia that couldn’t be analyzed otherwise. This COGS analysis uses linear dimensions as a way of describing the size, shape, and positions of facial bones. This linearity is very practical because surgeons think measurements through in their head in millimeters opposed to angles, when planning and accomplishing these procedures.
To aid the orthodontists and surgeons in this process CephX’s cloud based platform collects all of these components and measurements to easily record and store data to easily compare these values and relationships.