Dental Cements Flashcards
What is a liner?
A paste material applied in a thin layer on dentine before placement of a restorative material
What is a base?
A material applied in a thicker layer on dentine, used to replace missing dentine
What are the functions of liners and bases?
- Sealing dentine tubules to reduce possible pulpal injury resulting from microleakage
- Thermal insulation (intolerable changes in pulp temp due to metallic fillings)
- Chemical insulation (to protect pulp against irritants in some fillings)
- Electrical insulation (galvanic current/shock - meeting of 2 dissimilar metals)
What is Calcium Hydroxide used for?
- Lining a deep cavity over a pulpal wall
- Indirect pulp capping (some softened dentine may be left over pulp)
- Direct pulp capping (deep carious lesions involving exposure of the pulp or traumatic pulp exposure)
What is the composition of Calcium Hydroxide?
Base
1. 50% Ca(OH)2 - main reactive ingredient
2. 10% ZnO - (main reactive ingredient)
3. 0.5% Zinc stearate (accelerator)
4. 39.5% Ethyl toluene sulphonamide (oil compound acts as a carrier)
Catalyst
1. 40% Glycol salicylate (main reactive ingredient)
2 Inert filler pigments and radio pacifiers - Titanium dioxide, calcium sulphate, calcium tungstate.
What is the action of Calcium Hydroxide?
- Stimulates dentine deposition
- High alkalinity irritates odontoblasts causing stimulation for reparative dentine to be laid down.
- Does not seal dentinal tubules causing microleakage (unlike GIC)
What are the advantages of Calcium Hydroxide?
- Stimulation of reparative dentine
- Physical barrier
What are the disadvantages of Calcium Hydroxide?
- Low compressive strength
- Soluble
- Non-adherent to dentine
- High pH
- Exothermic reaction
What is the mixing time of Calcium Hydroxide?
10s
What is the working time of Calcium Hydroxide?
2 mins 20s
What is the setting time of Calcium Hydroxide?
2.5-3.5 mins
?What are the uses of Zinc Oxide Eugenol?
- Temporary restorations
- Bases
- Temporary luting cements
- Endodontic sealers
- Impressional material
What is the composition of Zinc Oxide Eugenol?
Powder:
• Zinc oxide (main reactive ingredient)
• Rosin (reduces brittleness)
• Zinc acetate (accelerator)
• Zinc stearate (plasticiser)
Liquid
• Eugenol (main reactive ingredient)
• Olive oil (to control viscosity)
• Acetic acid (accelerator)
What are the advantages of Zinc Oxide Eugenol?
Sedative
Bactericidal
Adequate mechanical properties
Inexpensive
Good track record
What are the disadvantages of Zinc Oxide Eugenol?
Difficult to mix
Opaque
Does not bond to tooth
Interacts with resin composite
Soluble in the mouth
What is the mixing time of Zinc Oxide Eugenol?
1-1.5 mins
What is the working time of Zinc Oxide Eugenol?
2 mins
What is the setting time of Zinc Oxide Eugenol?
3.5-4.5 mins
What is the powder:liquid ratio of Zinc Oxide Eugenol?
5:1 by weight
What are the uses of Zinc Phosphate cement?
- Base (but avoid if in close proximity to pulp)
- Long-term temporary restoration
- Cementation of: Inlays, Onlays, Metal-based crowns & bridges (not ceramic)
What is the composition of Zinc Phosphate cement?
Powder
Zinc oxide (90%) (main reactive ingredient)
Metal oxides (10%):
• Magnesium oxide (colour & strength)
• Aluminium oxide (strength)
• Silicone dioxide (colour & reaction)
Liquid
Aqueous solution of Phosphoric aid (50-60% conc)
Phosphoric acid + aluminium (buffer)
Phosphoric acid + zinc (stabilizer, reduces reactivity & increases working time)
What are the advantages of Zinc Phosphate Cement?
Relatively easy to mix
Sufficient working time
Acceptable properties for purpose
Cheap
Long successful track record
What are the disadvantage of Zinc Phosphate Cement?
Possibly irritant to pulp – exothermic reaction
Does not bond to tooth tissue or restorative materials
Brittle
No antibacterial effects
Opaque
What is the mixing time of Zinc phosphate cement?
1.5 mins
What is the working time of Zinc phosphate cement?
2.5 mins
What is the setting time of Zinc Phosphate cement?
5-6 mins for cementation; 3 mins for base
What are the uses of Zinc Polycarboxylate?
- Temporary restorations
• Useful for non-retentive cavities
• Sedative – doesn’t enter dentine tubules
• Good under resin-based composite restorations - Bases
• Good adherence - Luting of metal & metal-ceramic crowns or bridges
What is the composition of Zinc Polycarboxylate?
Powder
• Zinc oxide (main reactive ingredient)
• Stannous fluoride (improves set, fluoride release)
• Magnesium oxide (densifier, colour)
• Silica (improves sintering in manufacture)
• Alumina (forms complex with acid)
Liquid
• Polyacrylic acid (main reactive indredient)
• Itaconic acid (stabilises liquid)
• Maleic acid (reactive)
What are the advantages of Zinc Polycarboxylate cement?
Bonds to tooth or restorative materials
Long term durability
Acceptable mechanical properties
Relatively inexpensive
Long & successful track record
What are the disadvantages of Zinc Polycarboxylate cement?
Difficult to mix
Opaque
Soluble (particularly if stannous fluoride included)
Ill defined set
What is the mixing time for Zinc Polycarboxylate cement?
15-20 secs
What is the working time for Zinc Polycarboxylate cement?
2-2.5 mins
What is the setting time for Zinc Polycarboxylate cement?
4.5-7 mins
What is the mixing ratio (powder:water) for a base/temporary made of zinc polycarboxylate cement?
2 scoops: 2 drops
What is the mixing ratio (powder:water) for a luting cement made of zinc polycarboxylate cement?
1 scoop: 2 drops
What are the general properties of biodentine?
Bioactive & biocompatible dentine substitute
Natural micro-mechanical anchorage in the dentine tubules for excellent sealing properties without surface preparation
Similar mechanical properties as dentine
What is the composition of biodentine?
Powder
1. Tricalcium silicate (main component)
2. Dicalcium silicate (second core component)
3. Calclium carbonate (filler)
4. Calcium oxide (filler)
5. Iron dioxide (shade)
6. Zirconium dioxide (radiopacifier)
Liquid:
1. Water
2. Super plasticising agents (reduces
water content)
What are the indications of biodentine in the crown?
- Temporary enamel restoration
- Permanent enamel restoration
- Deep or large carious lesions
- Deep cervical lesions
- Pulp capping
- Pulpotomy
What are the indications of biodentine in the root?
- Root & furcation perforations
- Internal/ external resorptions
- Apexification
- Retrograde surgical filling
What is the mixing and placement time of biodentine?
6 mins
What is the setting time in the mouth of biodentine?
6 mins
How long should be waited before you place a permanent restoration over biodentine?
48 hrs
What is Tempbond (ZnOE) used for?
- Self curing temporary cement
- Temporary crowns, bridges or splints of trial cementation of permanent restorations
How do you mix Tempbond?
Equal lengths of accelerator and base on mixing pad
What is the mixing time of Tempbond?
30s
What is the working time of Tempbond?
3.5 mins
What is the setting time of Tempbond?
2 mins
What are the uses of Aquacem?
Permanent luting cement for Crowns, Bridges, Inlays, Onlays & Orthodontic bands.
What is the composition of Aquacem?
Powder
• Calcium-sodium-fluoro-phosphoroaluminium-silicate
• Polyacrylic acid
• Tartaric acid
• Ferricoxide
Liquid
• Distilled water
What are the advantages of Aquacem?
Safe & easy to use
Anticariogenic – fluoride release
High compressive strength
Low solubility
Low film thickness
Radiopacity
Translucency
What are the disadvantages of Aquacem?
Opaque
Not suitable for short/ unretentive tooth preparations
What is the mixing time of Aquacem?
15s
What is the working time of Aquacem?
2.5 mins
What is the setting time of Aquacem?
3.5-5 mins
What is the mixing ratio of Aquacem? (Powder:water)
1 scoop powder: 2 drops liquid
What are the indications of Panavia?
- Cementation of metal crowns and bridges, inlays and onlays
- Cementation of porcelain crowns, inlays, onlays and veneers
- Cementation of composite resin crowns, inlays and onlays
- Cementation of adhesion bridges
- Cementation of endodontic cores and pre-fabricated posts
- Amalgam bonding
What are the contraindications of Panavia?
- Patients with allergies to methacrylate polymers
- Patients with an allergy to acetone (alloy primers)
What are the possible side effects of Panavia?
Mucous membrane may turn white if in contact with the primer due to protein coagulation. (Will resolve in a few days)
In which situation is Panavia incompatible?
- Eugenol containing materials should not be used to protect the pulp or for temporary sealing as they retard the curing process
- Haemostatics containing ferric compounds since they may impair adhesion and remaining ferric ion may cause discolouration in margin or surrounding gingivae.
- Do not mix Panavia F with Panavia 2.0 as paste will not fully set on light curing.