Dr Nora sheta

Relief

The reduction of undesirable pressure from specific areas under the denture

Relief area: “ Area in the fitting surface of the denture that is reduced to eliminate excessive pressure.”

Defintion :

Relief areas Hard areas Sensitive areas Maxillary 1-Median palatine raphae 2-Torus palatinus {if present} Mandibular Maxillary Mandibular Torus mandibularis {if present} 1-Incisive papilla 2-Rugae area 3-Flabby ridge 4-Sharp bony spicules 1-Mental foramen in resorbed ridges 2-Flabby ridge 3-Sharp bony spicules

Shape of Relief Area

It is never well defined. It merges into the surrounding fitting denture surface.

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

Methods of Relief I- Direct II- Automatic 1-Scrap the final impression 2-Build tin foil on the master cast

I- Direct Relief 1- Scraping the Impression

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

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 shrinkage.

for polymerization 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