Appendix 1

Acknowledgement

“Decontamination of impression materials and prosthetic and orthodontic appliances” from BDA Advice Sheet A12 “Infection Control in Dentistry”. Reproduced with permission from the British Dental Association (www.bda.org). Please note that these guidelines are subject to regular review.

This is an example of the advice given by National Dental Organisations to dental practitioners about cross-infection. In addition to the generic measures mentioned in this book the reader would be well advised to seek such national guidance as this will change from time to time.

Decontamination of impression

Materials and Prosthetic and Orthodontic Appliances. Extract from Advice Sheet A12: Infection Control in Dentistry, revised April 2006, reproduced with kind permission from the British Dental Association.

The responsibility for ensuring impressions and appliances have been cleaned and disinfected prior to dispatch to the laboratory lies solely with the dentist –

•Immediately on removal from the mouth, the impression or appliance should be rinsed under

running water to remove saliva, blood and debris. Continue the process until it is visibly clean. If an appliance is grossly contaminated, it should be cleaned in an ultrasonic bath containing detergent and then rinsed. The impression or appliance should be disinfected according to the manufacturer’s recommendations. Generic materials such as sodium hypochlorite (household bleach) may no longer be suitable for disinfecting impressions unless specifically recommended by the manufacturer. Disinfectants should not be sprayed onto the surface of the impression; it lessens the effectiveness and creates an inhalation risk. Immersion of the impression is recommended. The impression or appliance should be rinsed again in water before sending to the laboratory accompanied by a confirmation that it has been disinfected.

Products that are suitable for the disinfection of impressions or appliances are CE marked to demonstrate conformity to European Directives. The manufacturer’s recommendations for the dilution of the disinfectant and immersion time must be followed.

nickel-chromium alloys, see porcelain fused to metal

nickel, in alloys, 68, 72, 84 notch sensitivity, 11

orthodontic cements, 271, 287 orthodontics, bonding, 240

palladium, in alloys, 65, 69 Paramonochloropheno1, 290 passivating effect, for steel, 85 pearlite, see steel

phosphate cements, 273 composition, 274 manipulation, 273 properties, 275 setting, 273

plaster, see gypsum products platinum foil, see porcelain fused to

metal Poissons ratio, 8

polyalkenoates, see glass ionomers polycarboxylate cements, 24 polyethers, impression materials,

172 polymerisation, 101

activation, 102 addition reaction, 101

condensation reaction, 104 contraction, 107

free radicals, 101 heat of reaction, 107 initiation, 102

light-activated, 199, 204, 206 physical changes caused by, 105 propogation, 102

ring-opening, 104, 207 termination, 104, 197 see also polymers

polymers, 101

chain branching, 104 copolymers, 107 cross-linking, 104 crystalline, 109 fabrication, 109

glass transition temperature, 104

molecular weight, 104, 104 plasticiser effect, 104 structure and properties, 104 see also acrylics, denture base

polymers, polymerisation polysulphides, impression materials,

163

polyvinylsiloxane, impression materials, 169

porcelain

compaction and firing, 90 composition, 89

denture teeth, 133 properties, 91 veneers, 97

see also ceramics, procelain fused to metal

porcelain fused to metal, 97 bonded platinum foil, 100 capillary technology, 100 gold alloys for, 98

nickel-chromium alloys for, 99 silver-palladium alloys for, 99 tooth preparation for, 99

posts, 214

primers, for dentine bonding, 230, 234

proof stress, 9

proof stress of gold alloys, 63 proportional limit, 8 pseudoplastic, impression material,

136

pulp capping, 282

radiopacity, 110, 122 recrystallisation temperature, 55 refractory dies, see investments resilience, 9

resin-modified glass ionomers, 257

adhesion, 262 classification, 257

clinical handling notes, 264 composition, 94, 257 dimensional changes, 261 fluoride release, 263

for luting and lining, 287 mechanical properties, 262 setting, 261

water absorption, 261 radial pressure, 261

reversible hydrocolloids, agar, 154 rheology, 18

Bingham, 19 dilatant, 19 Newtonian, 19

of filling materials, 178 pseudoplastic, 19 rotary mixing, 247

setting time, 4, 19

setting characteristics, 175 of impression materials, 142

shelf life, 4

silicate cements, 180

silicone elastomers, soft lining materials, 129

silicones

addition type, 168 condensation type, 167

silicophosphate cements, 277 silver, alloy with palladium, 69 silver in endodontics, 291 silver-palladium alloys, see

porcelain fused to metal smart behaviour, 251

smear layer, in dentine bonding, 233

soft lining materials, see denture liners

soldering, 69

solid solutions, see alloys solubility, 27

stainless steel, 85 denture base, 86 see also wires

steel, 84 composition, 84 structure, 84 structure, 84

stone, see gypsum products strain, 7

strength, 7 compressive, 8 diametral 7 tensile, 8

transverse (flexural), 6 stress, 6

stress relaxation, 17 surface roughness, 211, 212 syneresis, of agar, 157

tarnish, 31

temporary soft liners, 128 thermal packing, 294 thermal properties, 21

coefficient of thermal, 23 expansion, of amlagam, 188 reaction exotherm, 22 thermal conductivity, 21 thermal diffusivity, 21

tissue conditioners, 126 titanium, see implants, wires titanium, 77

toughness, 10

veneers, see porcelain viscoelasticity, 14, 131 Maxwell model, 14 Voigt model, 14 viscosity, see rheology