Dr Nora sheta

Relief

The reduction of undesirable pressure from specific areas under

the denture

Defintion :

Relief area:“ Area in the fitting surface

of the denture that is reduced to eliminate excessive pressure.”

1-Median palatine raphae2-Torus palatinus {if present}

Torus mandibularis {if present}

1-Incisive papilla2-Rugae area3-Flabby ridge4-Sharp bony spicules

1-Mental foramen in resorbed ridges 2-Flabby ridge3-Sharp bony spicules

Shape of Relief AreaIt is never well defined. It merges into the surrounding

fitting denture surface.

It depends on the compressibility of the area to be relieved as wellas that of the surrounding areas.

Methods of Relief

I- Direct

1-Scrap the final

impression

2-Build tin foilon the master

cast

II- Automatic

I- Direct Relief

1- Scraping the ImpressionIn plaster of paris impression material

I- Direct Relief 2- Build on the cast

I- Direct Relief 2- Build on the cast

II- Automatic Relief (Selective Pressure Impression Technique)

A- Scraping the compound selectively.

B- Secondary impression in Zn/O eugenol or plaster.

Value of Relief • Relief of sensitive areas increases the comfort of the patient.

• Relief of hard areas improves the denture stability, so it

• Prolongs the duration of denture service by compensating for denture settling and some ridge resorption .

• Compensate for polymerization shrinkage.

Posterior palatal seal ”post dam”

Definitions

1- Posterior palatal seal :“ A slight elevation at the posterior border of

the maxillary denture .”

Definitions

2- Post damming :“ Slight compression of the soft tissues along

the posterior border of the denture whether upper or lower .”

Definitions

3- Posterior palatal seal area

“Area of resilient soft tissue at or beyond the junction between hard & soft palate, on which pressure within physiologic limits of tissue can be applied by the posterior border of the denture to aid in denture retention.”

Position of the Post dam area

Posterior vibrating line

Functions of posterior palatal seal

1. Retention of maxillary denture.2. Prevents food accumulation under the

denture.3. Compensates for polymerization

shrinkage.4. Reduces patient’s discomfort.

Requirement of the effective posterior platal seal

• Easily displaceable tissue• imovable tissue• Touch the soft palate during rest and function

Width of post dam area

Depth of Post Dam

Depends on the degree of compressibility of soft tissue in this area and on the extent of functional movement of the soft palate.

Methods of postdamming

1-Scraping method 2-Functional method

Methods of post damming

1-Scraping method

Methods of post damming

2- Functional method

Methods of post damming

2- Functional method

Post damming of the lower denture

• A lower impression may be post dammed by slightly compressing the soft tissues formming the pear shape retromolar pad