Topic 7: Facebows - Prosthodontics I

Vocabulary practice flashcards covering dental facebows, historical designs, anatomical reference planes, classifications, and clinical considerations based on Topic 7 of Prosthodontics I.

Facebow

A clinical instrument used to record and transfer the spatial relationship of the maxillary dental arch to the temporomandibular joints (TMJs) from a patient's mouth to a dental articulator.

Hayes' Facebow

The earliest known facebow, which utilized two posterior reference points and an anterior reference at the interincisal point.

Snow's Facebow

A facebow designed in 1899 that transfers the position of the upper jaw relative to the porion without referencing a defined cranial plane.

Virchow Plane (Frankfort Plane)

A horizontal skull base reference plane adopted in 1942 during a conference in Frankfurt.

Axis–Orbital Plane

A cranial reference plane defined by three landmarks: the two posterior condylar centers of rotation and the suborbital point anteriorly.

Standard Rotation Axis

An average anatomical reference location for the rotation axis, defined as $12\,\text{mm}$ anterior to the tragus along a line connecting the tragus to the outer corner of the eye.

Cylinder-Type Posterior Reference

A posterior element of a standard transfer facebow positioned over the skin projection of the standard axis to fit directly over the rotational axis of the articulator.

Intra-Auricular Olives

Posterior reference components inserted into the external auditory canals that connect to articulator attachments designed to compensate for the anatomical offset to the rotation axis.

Rigid Frame Axis–Orbital Facebow

A facebow design (e.g., Dentatus) maintaining parallelism between side arms with a millimeter scale, where the facebow is fitted to the patient first and then adapted to the articulator.

Mobile Frame Axis–Orbital Facebow

A facebow design (e.g., Almore) with non-parallel side arms adapted to patient anatomy, requiring the articulator to adapt to the facebow using adjustable intercondylar extensions.

Anatomical Facebow (Artex / Bio Art A7 Plus)

A self-centering facebow using ear olives and nasion support to form a stabilization tripod based on average anatomical measurements.

Intercondylar Distance Selection Rule

When selecting among the three preset intercondylar sizes (S, M, L) in anatomical facebow registration, the smaller size should be chosen if the patient's measurement falls between two sizes to reduce interference.

Clinical Indication for Standard Axis Transfer

Transfer of the standard rotational axis using a standard facebow, which is generally sufficient for complete denture fabrication.

Clinical Indication for Real Axis Transfer

Transfer of the patient's true rotational axis, recommended for ceramic rehabilitations to achieve high accuracy.

Christensen Phenomenon

An intraoral registration technique used to measure condylar slope values, making reference plane transfer unnecessary in cases requiring only a single articulator mounting.