drm313mac
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The "old fashioned" dentures were cold cure systems, the new systems, according to the literature, are thermoplastic. Each has plus and minus. Therefore, please correct me on all points where I am wrong.
First and foremost I want the denture to be homogenous, a continuity of all the same material throughout, and in this regard thermoplastic processing rules. Or does it? Is it the mixing process that gives homogeneity or is it the temperature of cure?
Second, according to the literature the cold cure results in between 5% and 11% distortion (shrinkage) upon polymerization, whereas thermoplastics have < 0.01% distortion. Then again, the literature that cited this was biased, as it is selling Flexite --- research bought and paid for by one company will usually favor that company.
Therefore, does thermoplastic polymerization result in less distortion?
Using engineering principals (undergraduate fields were primarily mathematical physics and engineering physics),common sense tells us that when we heat an item it will expand and when we cool it, it will contract. If item A is heated more than item B, if the items are the same in structure, item A will expand and contract more, usually. Therefore, will not thermoplastic polymerization result in greater distortion?
OR, will thermoplastic processing result in better structure IF that processing remains at a specific temperature? That is, instead of heating the acrylic to 400 degrees F, we do far less, what will be the trade-offs?
I want the denture to have as little porosity as possible. Thermoplastic curing is best here. Correct?
I want no micro-cracks. Here, it seems that how fast the denture cooled determines this. Some labs toss the heated denture into ice water, and based on experience (my brother and I were in the polar bear club),everything gets a whole lot smaller, and cold-cured metal, while harder becomes more brittle as well.
The reasons for all these questions? The answers will determine the equipment lists, as well as the engineering of the lab space.
I thank you in advance.
First and foremost I want the denture to be homogenous, a continuity of all the same material throughout, and in this regard thermoplastic processing rules. Or does it? Is it the mixing process that gives homogeneity or is it the temperature of cure?
Second, according to the literature the cold cure results in between 5% and 11% distortion (shrinkage) upon polymerization, whereas thermoplastics have < 0.01% distortion. Then again, the literature that cited this was biased, as it is selling Flexite --- research bought and paid for by one company will usually favor that company.
Therefore, does thermoplastic polymerization result in less distortion?
Using engineering principals (undergraduate fields were primarily mathematical physics and engineering physics),common sense tells us that when we heat an item it will expand and when we cool it, it will contract. If item A is heated more than item B, if the items are the same in structure, item A will expand and contract more, usually. Therefore, will not thermoplastic polymerization result in greater distortion?
OR, will thermoplastic processing result in better structure IF that processing remains at a specific temperature? That is, instead of heating the acrylic to 400 degrees F, we do far less, what will be the trade-offs?
I want the denture to have as little porosity as possible. Thermoplastic curing is best here. Correct?
I want no micro-cracks. Here, it seems that how fast the denture cooled determines this. Some labs toss the heated denture into ice water, and based on experience (my brother and I were in the polar bear club),everything gets a whole lot smaller, and cold-cured metal, while harder becomes more brittle as well.
The reasons for all these questions? The answers will determine the equipment lists, as well as the engineering of the lab space.
I thank you in advance.