Recording Maximum Mandibular Protrusion

The most important measurement is the patient’s ability to protrude the jaw. The range of normal protrusive ROM is 5 to 12 mm. For MAD therapy to successful, the patient must be able to demonstrate the ability to protrude the jaw and hold it there tolerably. For the purpose of MAD fabrication, a minimum protrusion of 5 mm is required. The measurement can be made with commercially available paper rulers, metal autoclavable rulers or any number of gauges designed for measuring protrusive capacity such as the George gauge.

Begin by measuring the degree of overjet present in millimeters. Next, ask the patient to protrude maximally and record the distance between the incisal edge of the maxillary central incisor to the incisal edge of the mandibular central incisor. Add this measurement to the amount of overjet to arrive at the maximum protrusion as measured in millimeters. Annotate this in the dental chart (Figures 8A‑B).

Figures 8. The process of recording maximum protrusion is crucial as this measurement will be referenced during the bite registration, laboratory fabrication and titration of the delivered mandibular advancement device (MAD).
Measuring protrusive capability by a disposable paper ruler.
A. Measuring protrusive capability by a disposable paper ruler.
A commercially available protrusion gauge, such as a George gauge.
B. A commercially available protrusion gauge, such as a George gauge.