Self-Curing
Write a short note on self-cure acrylic resin.
Answer:
It is also known as chemically activated denture base acrylic resin or cold cure or autopolymerizing resin.
Composition Of self-cure acrylic resin:
Liquid:
- Methyl methacrylate monomer − Dissolves/plasticizes
- Dimethyl-p-toluidine − Activator
- Dibutyl phthalate − Plasticizes polymer
- Glycol methacrylate (1–2%) − Cross-linking agent
- Hydroquinone − (0.006%) Inhibitor
Powder
- Poly (methyl methacrylate) other co-polymers — 5% − Dissolved by and monomer to form a dough
- Benzoyl peroxide − Initiator
- Compounds of mercuric sulfide, cadmium sulfide − Dyes
- Zinc or titanium oxide − Opacifirs
- Dibutyl phthalate − Plasticizer
- Dyed organic filers and inorganic particles like glass fibers or beads − For esthetics
Properties Of self-cure acrylic resin:
- Its flexural strength is low.
- It has low compressive strength, i.e. 65 MPa, and low tensile strength, i.e. 60 MPa.
- Its surface hardness is 16 to 18 KHN.
- It exhibits lower dimensional changes.
- Its water sorption is 0.5 to 0.7 mg/cm2
- It has a higher solubility rate, i.e. 0.05 mg/cm2
- It has poor color stability so esthetics are compromised.
- Yellowing of material occurs.
Uses Of self-cure acrylic resin:
- For making temporary crowns and FPDs.
- For denture repair, relining, and rebates.
- For making removable orthodontic appliances.
- For the construction of special trays.
- For fabrication of temporary and permanent denture bases.
- For fabricating inlay and post-core patterns.
Advantages Of self-cure acrylic resin:
- The initial fi is good.
- Helps in repairing dentures and does not lead to warpage.
- It is easy to manipulate.
- It exhibits less shrinkage.
- Its dimensional accuracy is high.
Disadvantages Of self-cure acrylic resin:
- Color stability is inferior
- Properties are inferior compared to heat-cure acrylic resin.
- Polymerization is incomplete.
- Its flxural strength is low.
- Residual monomer leads to tissue irritation.
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