Download - Dr Nora sheta
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