1. RETENTION, STABILITY & SUPPORT IN COMPLETE DENTURE

2. Factor affecting Successful denture fabrication

3. RETENTION
It is the resistance to removal in a direction opposite to that of insertion.
BOUCHER described retention as the most spectacular yet probably the least important of all complete denture objectives. This property may indeed be least important, it provides psychologic comfort to patient.

4. Factors affecting retention
. Anatomical factors . Physiological factors . Physical factors . Mechanical factors . Oral& facial musculature . Psychological effects and patient’s tolerance

5. ANATOMICAL FACTORS
1.Size of the denture bearing area 2.Quality of the denture bearing area

6. PHYSIOLOGICAL FACTORS
Saliva- Quality and viscosity

7. The most commonly listed factors of retention include-
A) PHYSICAL FACTORS
Adhesion
Cohesion
Interfacial surface tension
Capillary attraction
Atmospheric pressure.

8. B) BIOLOGIC FACTORS
Intimate tissue contact
Neuromuscular control

9. PHYSICAL FACTORS Adhesion
It is the physical force involved in the attraction between unlike molecules.

10. Cohesion
It is the physical attraction of like molecules for each other.

11. Interfacial surface tension
It is the resistance to separation possessed by the film of liquid between two well adapted surfaces.

12. Atmospheric pressure
It is the physical factor of hydrostatic pressure due to the weight of the atmosphere on the earth’s surface.

13. Mechanical factors
. Undercuts . Rotational insertion path . Parallel walls

14. Biologic factors
Intimate tissue contact - It is the biologic factor that refers to the close adaptation of the denture base to the underlying soft tissues.

15. Neuromuscular Control– It refers to the functional forces exerted by the musculature of the patient that can affect to retention.

16. STABILITY
“the resistance against horizontal movements and forces that tends to alter the relationships between the denture base and its supporting foundation in horizontal or rotatory direction.”

17. SUPPORT IN COMPLETE DENTURE
Complete denture support is “the resistance to vertical movement of the denture base towards the ridge.”
Support counteracts the forces at right angles to the occlusal surface directed towards the ridge.

18. FACTORS AFFECTING SUPPORT
Effective support is obtained when-
The denture is extended to cover maximum surface area without impinging on movable tissues.
Tissues most capable of resisting resorption are selectively loaded during function.
The initial denture support is achieved by using impression procedures that provide optimal extension & functional loading of supporting tissues.
Long term support is obtained by directing the forces of occlusal loading towards those tissues most resistant to remodelling & resorptive changes.

19. MCQs
1. Adequate retention in complete denture provides- a. Physiologic comfort b. Psychological comfort c. Physical comfort d. Longivity

20. 2. Which of the following factor is primarily essential for longevity of complete denture-
Retention
Stability
Support
Esthetics

21. 3. The factor necessary in complete denture to be firm , stable and constant while resisting horizontal and chewing forces is-
Retention
Stability
Support
Esthetics

22. 4. BOUCHER described which factor as the most spectacular yet probably the least important of all complete denture objectives-
Retention
Stability
Support
Esthetics

23. 5. Physical force involved in the attraction between unlike molecules is known as-
Cohesion
Adhesion
Surface tension
Capillary attraction