What is the recommended lip position for orthognathic evaluation?

The recommended lip position for orthognathic evaluation is when the lips are slightly touching. This position allows for a neutral facial appearance, which is crucial for accurately assessing dental and skeletal relationships within the oral cavity. A slight touch of the lips indicates that the mandible is in a natural and relaxed position, which is important for evaluating the occlusion and the relationship of the upper and lower jaws.

When the lips are apart, it may suggest altered jaw positions, such as an open bite or excessive overjet, which can lead to misinterpretation of the dental and skeletal relationships. Tightly closed lips could indicate excessive muscle tension or a guarded position, affecting the natural posture of the jaw. Extending the lips outward can also distort the facial aesthetics and misrepresent the normal occlusal relationships.

Maintaining the lips in a slightly touching position best serves the purpose of evaluating the functional and aesthetic factors relevant to orthognathic assessments.