Module 5 - Cement Flashcards
Materials made from two components, powder, and
liquid, mixed together.
Dental cements
Component of dental cement
liquid = acid
powder = base
mixing –> acid-base reaction
Use of dental cements (3)
- luting agent
- pulp protection/cavity sealer
- cavity varnish
- liner
- base
- filling
- temporary filling
- permanent filling
General requirements for cement
- biocompatibility
- retention
- high tensile strength, fracture toughness, fatigue strength
- good marginal seal
- low film thickness
- ease of use
- radiopacity
- esthetics
how much layer of cement for base is applied under restoration to protect pulp against injuries
> 0.75mm
classification of cement bases
- type I - luting cement
- type II - permanent cementation
- type III - temporary restoration
- type IV - cavity liner
types of dental cements (5)
- zinc oxide eugenol
- Glass ionomer
- Calcium hydroxide
- Polycarboxylate
- Zinc phophate
working time and setting time of type 1 fine grain
3-6 minutes, 2.5-8 minutes
used for the permanent cementation of cast restorations such as crowns, inlays, onlays, and bridges
type I (fine grain)
recommended for use as insulating base for deep cavity preparations
type II (medium grain)
how to increase the setting time
- reducing powder/liquid ratio (not recommended)
- mixing on the cool glass slab (no moisture)
- Mixing over a large area. Mixing cements by increments
composition of ZOE powder
- zinc oxide (principal)
- rosin (to reduce the brittleness of the set cement)
- zinc stearate (plasticizer)
-zinc acetate (improve strength)
Composition of ZOE liquid
eugenol and olive oil
Types of ZOE Cement
- Reinforced ZOE
- Simple ZOE
- EBA (ethoxy benzoic acid) and Alumina Modified Zinc oxide Cement
this is classify as sedative effect
reinforced ZOE
Lower strength than zinc phosphate cement. Usually used as temporary filling.
Simple ZOE
this tests for proper consistency for luting
string test
Also called zinc polyacrylate cement
Polycarboxylate cement
The first adhesive cement . Bond to tooth structure and metal
Polycarboxylate cement
composition of Polycarboxylate cement (powder & liquid)
Powder
- zinc oxide
- magnesium oxide
- stannous fluoride
Liquid
- Aqueous solution of polyacrylic acid
- other carboxylic acid
This is used as permanent cement for cast restorations, stainless steel crowns, and orthodontic bands
polycarboxylate
used as nonirritating base under both composite or amalgam restorations
polycarboxylate
used as an intermediate restoration
polycarboxylate
Zinc phosphate cement ratio of type 1 - luting cement
Ratio 4 - 4
