Polymer4\ Flashcards
Non- metallic denture
base Properties
1-polymrizition shrinkage:
Polymrizition of the monemer results in 25% voulmtric shrinkage
When mixing the polymer with the monemer the voulmtric shrinkage free 6%
2-residual shrinkage: thers no 100% polymrizition thers always will be remenante monemers which will cause irrititon
And the plastizers causes the denture to be weaker and flexible and less meachnical proprties
3-water sorption: the denture after proscessing will expaned due to te water w 1% and linal expantion 0.23%
And when the denture dries it will shrink
Thermal shrinkage also is possible due to the dif in the tem between the prosxssing and the room temperature ( 75C to 20C)
4- solubility: PMMA is soulble in the solvent and insoluble in the fluids
5- Mechanical Properties: its weak and the impact strength should be high to prevent the denture from breaking
6-thermal Properties: when the thermal conductivity is the denture will absorb all the heat and will cause increasing in the tm and will isolate the tissue
7-porosities:
1-shrinkage poristy: caused by under packing before the dough stage and ecses monomer and lack of sapriting medium
Found on the surface of the dent and its irredular
2-gauses porsity: caused boiling monomer
Found on the bulckest portion of the dent and its round regular
8-crazing:
Mechancal> repetaed weting and drying out
Thermal> dif of thermal expantion between the dent and teeth
Bleachig
Cleaning
When theres no sapriting medium
