Kaylor Dental Lab, Inc.
619 N. Florence
Wichita, KS 67212-2136
316-943-3226 -- out of Wichita, call 1-800-657-2549

Denture Department

Neutral Zone (Edentulous) Dentures

Note the black lines starting at the cuspid areas and extending distally following the crest of the lower ridge. Dentistry has taught that the buccal cusp be placed over the crest of the lower ridge when positioning the posterior teeth
For most patients this is OK, but for some it may position the lingual cusp so far lingually that it creates undercuts the tongue can get under.

The posterior teeth on this setup need to be moved bucally to remove the undercut created by the teeth position.

Note the first and second molars set on this baseplate. The 4 molar teeth’s buccal cusps are over the crest of the ridge, the lingual cusps of the molar teeth have created undercuts large enough for the tongue to unseat the lower denture during talking, swallowing and when the patient is chewing food.
Note on the these teeth the lingual cusps are in line with the crest of the ridge. There are no lingual undercuts. The tongue would not be restricted on this case by any of the posterior teeth.

When it’s necessary to position the lingual cusp of the lower teeth over the crest of the ridge. To eliminate the undercut we must be concerned about cheek biting when setting the upper teeth.

Setting the upper teeth in a cross bite position, when it is necessary, will solve cheek biting problems. Cross bite set ups rarely cause problems for the patient.

A. The mandibular neutral zone is an area where the lower teeth can be positioned between the tongue and cheek without infringing on the tongue.
B. The maxillary neutral zone is an area where the upper teeth are positioned to occlude with the lower teeth between the tongue and cheek without infringing on the cheek.
C. Setting teeth in the neutral zone position will assist the denture patient to be more comfortable wearing dentures.
I contend when we position lower teeth that don't capture the patient’s tongue, and then position the upper teeth in occlusal contact with the lower that won’t cause cheek biting. We have set the teeth in a neutral zone position for the patient.

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