Dentures Chapter 17

What is one of the major causes of complete denture rejection by patients?

Errors in tooth positioning, especially anterior teeth.

What two errors account for a large majority of denture rejections?

Improper tooth position and errors in vertical dimension.

What is the general goal of tooth placement in dentures?

To replicate the position of natural teeth with modifications for occlusion and improved esthetics.

Should all patients be given a Class I occlusion when placing denture teeth?

No, corrections to Class II and III malocclusions should be made within limits.

Why can't a flat incisal guidance always be achieved in retrognathic patients?

Because compromises in occlusal balance are needed to ensure proper display and function.

What does Tallgren's study indicate about ridge resorption over 25 years?

9-10 mm loss in the lower arch and 2.5-3 mm in the upper arch.

What is one artistic guide to proper anterior tooth position?

Observing attractive natural teeth to avoid excessive tooth or base display.

What are three types of pre-extraction records that help guide anterior tooth position?

Photographs, pre-extraction casts, and immediate dentures.

Which speech sounds are most useful in evaluating tooth position and vertical dimension?

Sibilant sounds ('s', 'sh', 'ch') and labiodental sounds ('f', 'v').

In a normal 's' sound, where should the mandibular central incisors be positioned relative to maxillary?

1 mm inferior and posterior to the maxillary central incisors.

What is the ideal contact point of the maxillary central incisors during 'f' and 'v' sounds?

On the inner curvature of the lower lip.

What does projecting roots from denture teeth to the ridge help evaluate?

Whether teeth are placed in a natural, functional position.

What guides the midline placement of denture teeth?

The center of the lips and lower third of the face, often aligned with the incisive papilla.

What tool helps establish initial occlusal plane orientation?

The Fox Occlusal Plane Guide.

How should the occlusal plane relate to the retromolar pad?

It should intersect near the center of the retromolar pad.

When should values from old dentures modify tooth positioning?

In long-term wearers with neuromuscular adaptations, especially older patients.

What general guideline applies to posterior tooth position over the ridge?

Central grooves of lower teeth should align over the crest of the ridge.

What should be considered if a patient has a large tongue?

Teeth should be positioned to avoid crowding or displacing the tongue.

What indicates vertical dimension may be too high?

Difficulty with lip closure or excessive upper tooth display.

What speech problems may result from teeth set too far back?

Whistling or lisping, especially during 's' sounds.

What error is suggested by a convex facial profile and whistling 's' sounds?

Teeth set too far out.

What is a likely consequence of setting maxillary anterior teeth too far down and back?

Excess base and tooth display, and improper 'f' position.

What is one sign of an overclosed vertical dimension?

Flat palatal contour or lack of lower anterior tooth display.