Dental Ceramic Techniques Flashcards
Name some ceramic systems.
Aluminous core (PJC) e.g. Vitadur Porcelain fused to metal (bonded crowns) e.g. Vita Platinum foil veneers Injection mounded ceramics Refractory based ceramics Ceramic restorations e.g. Belle Glass NG
What is aluminous core?
Alumina reinforced feldspathic porcelain utilising platinum foil matrix
What are the advantages of aluminous core (PJC)?
Inexpensive No specialised equipment Aesthetic matrix Biocompatible Ideally for post crowns only Platinum foil recycled
What are the disadvantages of aluminous core?
Technique sensitive Anterior teeth only Cannot be acid etched Marginal fit suspect Destructive lingual prep Not suitable for implants
What is porcelain fused to metal?
Feldspathic porcelain (glass) with high leucine crystal content increasing thermal expansion to that of metal bonding alloys
What are the advantages of porcelain fused to metal?
Relatively inexpensive May be used for bridges High strength Precision attachments Excellent marginal fit Metal occlusal possible Ideally suited to implants
What are the disadvantages of porcelain fused to metal?
Un-aesthetic margin Destructive labial prep Metal allergies? Metal to porcelain bond questionable Biocompatibility
What are platinum foil veneers?
Leucine reinforced feldspathic porcelain adapted for the foil matrix technique.
When would you use porcelain fused to metal?
Implants
Fixed prosthodontics - crowns, bridges
What are the advantages of platinum foil veneers?
Relatively inexpensive No special equipment Normal cast prep Platinum foil reclaimed Can be fabricated quickly Biocompatible
What are the disadvantages of platinum foil veneers?
Technique sensitive Prone to fracture during fabrication Must be etched with hydrofluoric acid Marginal fit suspect Not suitable for implants
What are refractory based ceramics?
Zirconia reinforced feldspathic porcelain applied to refractory models
What are the advantages of refractory based ceramics?
Aesthetic matrix
Good marginal fit
May not need to be acid etched
May be resin bonded
What are the disadvantages of refractory based ceramics?
Expensive refractory materials
Specialist equipment may be necessary
Model duplication and refractory prep may incorporate errors
Single units only
What are injection mounded ceramics?
Heat pressed leucite feldspathic porcelain with glass matrix.
Ceramic injected into a clear mould.
What are the advantages of injection mounded ceramics?
Good marginal adaptation Lost wax technique may be used for fabrication May be used for posteriors Translucent matrix Biocompatible
What are the disadvantages of injection mounded ceramics?
Expensive ceramic blocks Specialist equipment necessary Translucent matrix (shade only 40-50microns) Single units only? Not suitable for implants
What is Cad-Cam ceramics?
Factory produced machinable ceramics fabricated with computer aided design.
Uses an intra-oral scanning system (no impressions required)
What are the advantages of Cad-Cam?
Industrially produced matrix Machinable matrix Biocompatible May be used for bridges Surgery fabrication possible
What are the disadvantages of Cad-Cam?
Very expensive equipment
Expensive ceramic blocks
Uniform colour?
What are ceromeric restorations?
Ceramic optimised polymers e.g. Belle Glass
Not as rigid as pure ceramic - allow some flexibility.
Good in canine guidance area for this reason.
What are the advantages of ceromeric restorations?
High flexor all modulus Excellent aesthetics May be used for bridges Thermal coefficients of expansion v close to natural teeth Repairable intra orally Wear rate v close to natural teeth
What are the disadvantages of ceromeric restorations?
Expensive Reinforcement necessary Water absorption? Specialised equipment necessary Single units only for implants
What are the constituents of dental ceramics/porcelains?
SiO2 (57%) AlO2 (16%) KaO2 (11%) Na2 (9%) Other metal oxides