Determinants of mandibular movements are the influences determining the envelope of possible movements of the mandible. These influences may be:
• Posterior determinants (i.e. the temporomandibular joints and anatomical structures associated with them, also termed condylar guidance/posterior guidance).
The tooth surfaces that are in contact during an excursive movement are said to 'guide' movement of the mandible. The type of guidance may be divided as below, the divisions broadly describing the teeth that provide the guiding surface:
• Anterior guidance - the tooth surfaces that are in contact during a protrusive excursion. This is normally the incisor teeth, and hence is then termed incisal guidance: in some cases (for example an occlusion with an anterior open bite) it may actually be the posterior occlusal tooth surfaces that provide the anterior guidance.
• Canine guidance - when a lateral excursion is made, the canines on the working side are the only teeth to make contact.
• Group function - when a lateral excursion is made, multiple pairs of teeth on the working side make contact.
Tooth contacts during dynamic excursive movements that do not provide a smooth guidance, or separate guiding surfaces, may be termed an interference.
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