Cd priniciple

CD parts and thier Mechanism - Denture should fit in the oral cavity by retention(fiting) - Occlusal rims or gums should in jaw relation(movements) - Teeth should in occlusion

Denture Mechanisms for Retention¶

1. Capillary Action¶

Experiment: - Materials: Two glass slabs, water. - Procedure: Pour water on the surface of one glass slab and place the second slab on top. The slabs will stick together and be difficult to separate.

Analogy: - The two glass slabs represent the denture and the palate (or tissue). - The water represents saliva.

Explanation: - Surface Tension: The surface tension of the water creates an attraction between the glass surfaces. Surface tension is related to the interaction between liquid molecules and the surface area. - Adhesion and Cohesion: Adhesion (water molecules sticking to the glass) and cohesion (water molecules sticking to each other) play key roles. These forces are enhanced by the viscosity of saliva, which helps maintain the seal between the denture and the tissue.

Formula: Surface tension = Surface tension is directly proportional to surface area

Cohesion =

Cohesion directly proportional to viscosity of saliva

2. Suction¶

There is a pressure across all areas retained by capillary action but this pressure can't bearable in some sensitive areas called stress reliefing areas.which is painful for patient so,we need to create a space between denture and palate(or tissue) by spacer

Experiment: - Materials: A glass(modified glass slabe making space), a glass slab, water. - Procedure: Fill the glass halfway with water, place the glass slab on top, and turn the glass upside down. The water and glass slab stay in place due to the pressure difference. - Explanation: When the glass slab is placed over the water and the glass is inverted, the water creates a seal, trapping air and forming a partial vacuum. This results in lower atmospheric pressure inside the glass compared to outside.

Analogy: - The glass represents the denture, and the space inside the glass represents the relief areas to reduce stress on the tissue. - The water represents saliva.

Have ever suck an empty glass stick into your mouth which will seperate until the glass border kept opened

Explanation: Border Molding: Proper border molding in dentures ensures the edges seal well against the gums, maintaining the low atmospheric pressure inside i.e vaccum thereby retention

3. Muscular Movements¶

Denture won't to be come out by muscular moments so,

Experiment: - Materials: clay, A glass, a glass slab,water. - Procedure: Add clay around the rim of the glass, extending the borders to form a holding attachment. Fill the glass with water and cover it with the glass slab, sealing the borders with clay.

Analogy: - The clay represents the lips and muscles of the mouth, which form a holder around the outer part of denture.

Explanation: - Muscular Control: The muscles of the mouth, including the lips, cheeks, and tongue, help to keep the denture in place by forming a hold and adjusting the position during use. This dynamic fit contributes to the overall retention and stability of the denture.

Conclusion¶

Each mechanism is crucial for ensuring that dentures fit securely and comfortably:

Capillary Action: Utilizes the physical properties of saliva and surface interaction to create retention.
Suction: Depends on the principle of low atmospheric pressure created by a vacuum.
Muscular Movements: Relies on the natural movements and positioning of the mouth's muscles to maintain denture placement.

By understanding these mechanisms, dental professionals can design and fit dentures that provide better comfort and functionality for the wearer.

Occlusial rims mechanism for jaw relation¶

TMJ is cause of movements.The fact of TMJ is we can only move mandible.It makes maxillo-mandible relation or jaw relation

The movements are in three dimensions or planes - Sagittal Plane - Coronal Plane - Transverse Plane

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Axis is not towards face it is towards head vertically

Transverse plane¶

Superior/Vertical Dimension of Occlusion (VDO): The mandible is moved up Inferior/Vertical Dimension of Strech(VDS):The mandible is moved down Vertical Dimension of Rest (VDR): The mandible at rest i.e open bite/freeway sapce

Coronal plane¶

Anterior/Protrusive Relation: The mandible is moved forward. Posterior/Retrieve Relation: The mandible is moved backward(not possible) Central relation: The mandible at rest(it is centric relation) i.e overjet

Sagittal plane¶

Right Relation: The mandible is moved to the right Left Relation: The mandible is moved to the left Centre relation: The mandible at mid i.e coincidence midline

oriental=So the biting plane is straight to cranial plane i.e eyes as reference Centrical=bitted and rest position

Teeth mechanism for Occlusion¶

Difference table

Occlusion is defined as "any contact between the incising or masticating surfaces of the maxillary and mandibular teeth".

Occlusion is an important factor which governs the retention and stability of the complete denture in vivo.

Five factors for balanced Occlusion