What mandibular position is assumed when the head is upright and the muscles are in equilibrium?

• A. Physiological Rest Position
• B. Centric Occlusion
• C. Centric Relation
• D. Maximum Intercuspation

Answer: (A)

When the head is upright and the jaw muscles are relaxed and balanced, the mandible sits in a physiological rest position. In this position the muscles are at rest, there is minimal activity, and the teeth are not in functional contact—there is a small freeway space between the arches. This contrasts with tooth-contact positions like centric occlusion or maximum intercuspation, which require the teeth to touch, and with centric relation, which is a defined skeletal jaw position (condyles seated in the fossae) used as a reference rather than a resting, muscle-balanced posture. Therefore, the described scenario best matches the physiological rest position.