Compasso De Willls

The Compasso De Willls is a flat sliding gauge instrument constructed from high-grade stainless steel with a mirror-polished scale surface. Unlike every instrument preceding it in this catalog, this is a purely measurement device, no working tip, no jaw, no bending function. The body consists of a fixed upper arm with a horizontal reference bar and a sliding lower arm controlled by a knurled locking nut visible at the instrument mid-body. Both faces of the sliding ruler carry millimeter graduation marks from 0 to 100mm, laser-etched for long-term legibility. The Leader Surgical brand mark is engraved on the ruler body.

The locking nut fixes the sliding arm at any measured position, allowing the clinician to transfer a facial landmark measurement from one reference point to another without losing the set value between comparisons. The Willis method uses this instrument to confirm that the distance from the outer corner of the eye to the labial commissure equals the distance from the subnasale to the gnathion, the two measurements should match at correct vertical dimension. The instrument is fully autoclavable at 134°C and meets CE and ISO 13485 standards.

Prosthodontists and restorative dentists use the Compasso De Willls during complete and partial denture fabrication, recording the patient’s Vertical Dimension of Occlusion (VDO) before tooth extraction or during wax rim adjustment, and verifying VDO at trial denture insertion. The instrument is also used during implant-supported prosthesis planning to confirm occlusal vertical dimension against facial proportions. Ortocentral and Biodental supply networks list this instrument as a standard VDO assessment tool across Latin American prosthodontic markets.

Leader Surgical produces this gauge with verified millimeter-scale accuracy and consistent locking nut tension, ensuring the sliding arm holds its set position without drift during facial landmark transfer. This is the Compasso de willis standard format used across dental schools and prosthetic clinics globally.

How does it help in determining the “Ideal” bite height?
Clinicians use it to measure the distance between the nose (subnasal) and the chin (menton) in two states: at rest and with teeth touching. The difference between these two measurements, known as the Free Functional Space, should typically be between 2 to 4 mm for optimal patient comfort and function.