Stepby Step Procedure

1. Manipulate the mandible and mark the teeth so both the initial contact in centric relation and the extent and direction of jaw movement to in-tercuspation are seen. This movement, or slide, can be in either an anterior or a lateral direction.

2. Find any interferences that cause the condylar processes to be displaced anteriorly (protrusive interferences). These will usually be between the mesial inclines of maxillary teeth and the distal inclines of mandibular teeth (Fig. 6-28).

3. Continue the adjustment until all teeth contact evenly (except possibly the incisors). If excursive movements are guided adequately by the canines, it may be better to stop when bilateral canine-to-canine contact has been reestablished.

4. When dealing with a laterally displacing prematurity, adjust the buccal-facing inclines of the maxillary and the lingual-facing inclines of the mandibular teeth. The premature contact will usually be on either the laterotrusive or the mediotrusive side of the mandible (lateral slide or medial slide).

5. When dealing with a lateral slide, adjust the buccal inclines of the maxillary lingual cusps and the lingual inclines of the mandibular buc cal cusps until there is contact on the cusp tips (Fig. 6-29).

6. When dealing with a medial slide, adjust the buccal inclines of the mandibular buccal cusps or the lingual inclines of the maxillary lingual cusps until there is contact on the cusp tips. At this time, any further adjustments can be made through widening of the opposing central grooves by reduction of the internal inclines of

Mandible Structures
Fig. 6-28. interferences that deflect the mandible anteriorly (protrusive interferences) are found between the mesial inclines of maxillary teeth and the distal inclines of mandibular teeth.

the maxillary buccal and mandibular lingual cusps (Fig. 6-30).

Evaluation. The foregoing rules for occlusal adjustment should be followed as closely as possible while maintaining the normal anatomic form of the tooth. When the discrepancy between CR and MI has been corrected, there will be uniform contact between all posterior teeth. This can be verified with thin Mylar shim stock held in forceps (Fig. 6-31).

Elimination of Lateral and Protrusive Interferences. The second phase of occlusal adjustment concentrates on laterotrusive, mediotrusive, and protrusive interferences. Use red and blue marking

Buccal Incline Lingual Cusp

Fig. 6-29. Laterally displacing contact between the buccal incline of a maxillary lingual cusp and the lingual incline of a mandibular buccal cusp.

ribbons to distinguish between centric and eccentric contacts.

The goals of this second phase of adjustment are to eliminate contact between all posterior teeth during protrusive movements and to eliminate any interferences on the nonworking (mediotrusive) as well as the working (laterotrusive) side. In certain patients, group function of the working side contacts should be considered rather than the more

Laterotrusive Movement
Fig. 6-30. Correcting a medial slide by selective grinding. A, The contacting inclines are adjusted until the cusp tips are in contact (B). The opposing central grooves are then widened (C and D).
Mylar Shim Stock

Fig. 6-31. Verifying occlusal contacts with thin Mylar shim stock.

Fig. 6-29. Laterally displacing contact between the buccal incline of a maxillary lingual cusp and the lingual incline of a mandibular buccal cusp.

Fig. 6-31. Verifying occlusal contacts with thin Mylar shim stock.

ideal mutually protected occlusion (e.g., when there is mobility or poor bone support of the canines). In other patients, group function may be retained because of wear or malpositioning of the canines.

During this phase of adjustment, it is essential that no centric contacts be removed. In general, lateral and protrusive interferences are eliminated by creating a groove that permits escape of the centric cusp during eccentric movement (Fig. 6-32).

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    What is mesial incline of the tooth?
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