Dental Cements

Only available on StudyMode
  • Topic: Zinc, Acid, Phosphoric acid
  • Pages : 2 (483 words )
  • Download(s) : 73
  • Published : February 1, 2013
Open Document
Text Preview
Dental Cements
Acid-base rxn cementsResin-based cements
Phosphoric acidOrganometallic chelatePolyalkenoic
compoundacid

Zinc phosphateZOEPolycarboxylateGlass ionomercompomer Silicateconventionalcomposite
Zinc silicophosphateresin-modified

Cement| Composition| Setting rxn| Properties| Uses| Adv| Disadv| Zinc phosphate(ZP)| Powder: ZnOLiq: Phosphoric acid| 3Zn + 2H3PO4 Zn3(PO4)2 + H2O-s/f of ZnO dissolved by acid to give insoluble phosphate-set cement heterogenous (core of unreacted ZnO in a matrix of ZP)| 1. low film thickness2. high compressive strength3. low tensile strength4. sufficient thermal insulation5. may irritate pulp initially due to pH 2-46. acceptable solubility7. no chemical bond- non adhesive to enamel/dentine, depends on mechanical interlocking w/ rough s/f of cavity n restoration)8. opaque| -luting-liner| -high compressive strength-acceptable film thickness| -low initial pH lead to post-cementation sensitivity-no chemical adhesion-lack anticariogenic effect (no F-)| Silicate| Aluminosilicate glass powderAq sln of H3PO4| *acid base rxn same as ZP-set material consists of cored s/t of unreacted glass particles sheathed by s/f gel, embedded in amorphous gel| 1. Very acidic2. highly soluble, leaky3. release F| No longer use| | | Silicophosphate| Powder: ZnO & aluminosilicate glass| Same rxn as silicate but w/ fmx of ZP| Release F| Rarely use now| | | ZOE| Powder: ZnO mainRosin brittleness Zn acetate acceleratorLiquid:Eugenol mainOlive oil viscosityAcetic acid accelerator | ZnO + 2 C10H12O2 Zn(C10H12O2)2+H2O-finer particles react faster-no rxn in absence of water| 1. neutral pH2. bacteriostatic3. obtundent4. low thermal diffusivity5. good electrical insulation6. kind to pulp7. adequate WT8. x adhere to enamel/dentine9. weakest mechanical properties10. highly soluble| -liner-temp restor-temp cement for tmp/per...
tracking img