Retention, Stability And Support Of Complete Denture
Stability and support in complete dentures.
Answer:
Stability is defined as, “The quality of a denture to be firm, steady, or constant, to resist displacement by functional stresses and not to be subject to change of position when forces are applied.” GPT
Factors Affecting Stability
- The vertical height of the residual ridge:
- A parallel well rounded vertical ridge form offers better stability than resorbed ridges.
- Quality of soft tissue covering the ridge:
- Firm resilient tissue is able to withstand masticatory forces with better stability than thin or flabby tissues.
- Quality of the impression:
- An impression should be accurate and should duplicate all the details without any voids. The impression should be made of dimensionally stable materials and should be poured immediately.
- Occlusal plane:
- The occlusal plane should be oriented parallel to the ridge maintaining adequate interocclusal distance, this enhances stability.
- Teeth arrangement:
- The teeth should be arranged in a balanced occlusion and neutral zone.
Read And Learn More: Complete Dentures Question and Answers
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- Balanced occlusion is the simultaneous contacting of the maxillary and mandibular teeth on the right and left and in the anterior and posterior occlusal areas when the jaws are in either centric or eccentric relation.
- Balanced occlusion facilitates the even distribution of forces across the denture. The absence of balanced occlusion leads to a loss of stability.
- Thick saliva decreases complete denture retention, creates hydrostatic pressure in the area anterior to the posterior palatal seal, and results in a downward dislodging force.
- Thick saliva also complicates impression-making by forming voids in the impression surface. Hence before impression making the palatal surface should be wiped free of saliva and the mucus glands massaged with a piece of gauze to eliminate as much mucus as possible.
- The teeth in the denture should be arranged in the neutral zone. The neutral zone is defined as, “The potential space between the lips and cheeks on one side and the tongue on the other. Natural or artificial teeth in this zone are subject to equal and opposite forces from the surrounding musculature.” –GPT
Factors Affecting Stability The contour of the Polished Surface
From the cuspid to the posterior aspect the denture surface slopes slightly inward creating space for a buccal corridor. The overall contour of the denture should be in terms of the Neutral zone concept.
Factors Affecting Stability Support is defined as, “The resistance to vertical forces of mastication, occlusal forces, and other forces applied in a direction towards the denture-bearing area.”
- Maximum coverage provides the “snowshoe” effect, which distributes applied forces over wide an area as possible.
- Confining the occlusal forces to stress-bearing areas and reliving the non-stress-bearing areas will aid to improve support.
Factors affecting stability and support
- Maximum coverage of the basal seat within the limits of the health and functions of the supporting and limiting tissues.
- Borders that are in harmony with the anatomic and physiologic limitations of the oral structures.
- A physiologic type of border-molding procedure.
- Proper space is ensured in the tray for final impression material.
- Selective pressure technique for the final impression.
- Ideal impression material to be used depending on the clinical situation.
- A guiding mechanism for correct positioning of the impression tray in the mouth.
- The tray and final impression should be of dimensionally stable materials.
- The completed final impression form is similar to the external form of the completed denture.
- Accurately fitting final impression tray.
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