Occlusion: Clinical Procedures
Even if an occlusal status quo is envisaged, a preoperative occlusal assessment is worthwhile. Furthermore, it is instructive to know the patient’s occlusal status so that the treatment provided does not disturb the existing occlusal equilibrium. This chapter describes the salient clinical procedures of an occlusal examination.
To observe centric occlusion (CO), the patient is asked to bite on their posterior teeth, so that maximum intercuspation position (MIP) is achieved. In this position there should be maximum contact between opposing teeth, which is dependent on tooth shape and neuromuscular ‘memory’.
Centric relation (CR) is a predictably reproducible anatomical position. In order to place the mandible in CR, a transient neuromuscular amnesia is necessary so that the mandible can be freely guided into its most posterior and superior location, rather than its habitual CO. Methods to place the mandible in CR include:
- Bimanual mandibular manipulation;
- Anterior deprogramming with a jig;
- Gothic arch tracing.
Visual and Tactile Inspection
A visual examination requires the following armamentarium: photographic documentation, Shimstock foil, articulation paper and study casts to view the teeth from the lingual perspective.
Placing the mandible in CR allows the initial tooth contact to be observed, and subsequent slide (if any) into CO. Articulation paper of one colour is used to mark tooth contact in CO. Another paper of a different colour is used to superimpose contacts during various mandibular excursions. This allows clear distinction between CO and guiding contacts, as well as discriminating eccentric contacts or interferences. The supporting cusps in/>