Lecture 10- Temporary direct restorations materials

Materials for temporary direct restorations: protective restorations (4)

• zinc- oxide eugenol

• calcium- sulfate

• light cured resin

• gic

1) zinc oxide eugenol (ZOE)

• Z O E (reinforced with PMMA)

• self cured 

• base protective restoration

• eugenol inhibits polymerization

2) Calcium sulfate based

• calcium sulfate zinc oxide sulfate  

• hygroscopic setting

• high expansion

• setting time 2 hrs

• ex: Cavit

• harden through hydration, not polymerization (water like saliva)

• used for small cavities (use spoon exavator or carbide bur or cavitron to remove to avoid touching tooth structure), endo access and small inlays (no need for bur to remove)

3) resin base materials

• light cured polymerization reaction

• contains flouride

• uses: inlays/ onlays/ impant screw sealing

• cure the resin base temp filling for 20 seconds

4) glass ionomer cements (GIC)

• used in conjunction with protective coatings or sealants to improve its wear resistance and durability

• temp cement: glass (base) mixed with acid reaction

• calcium aluminosilicate with polyacrylic acid 

• bonds to tooth

• uses: protective restoration, endo access, class v

GIC indications

• luting cements

• ortho cements

• fissure sealants

• direct restorations

• core build up

• base/ restorative foundations

• liners

cavity liner

• It is in the coating, varnish, or other protective material to cover the dental cavity wall and protect dentin and pulp from sensitivity

• Usually a resinous film-forming agent in a volatile solvent, or a suspension of hydroxide in a solution of a synthetic resin.

base/ restorative foundation

• Substance placed under a restoration that blocks out undercuts in the preparation, acts as a thermal or chemical barrier to the pulp, and/or controls the thickness of the overlying restoration.

core build up

Foundation restoration which restores sufficient coronal anatomy of a vital or endodontically treated tooth

The setting reaction of glass-ionomer cement is characterized by an ______.

This involves the reaction between the polyacrylic acid (an acid) and the calcium-fluoro-aluminosilicate glass powder (a base), acid attacks glass particles which releases ions (calcium, aluminium, flouride), leads to the formation of a salt matrix and the setting of the cement.

acid-base reaction

Gic flouride release

• fluorapatite is less soluble to acid than hydroxyapatite so more resistant to acid attack

• flouride release decreases overtime

applying temporary protective varnish (glycerin gel) over gic:

• bec moisture sensitive

• do not have too much water or too dry while setting

• light cure after last increment before polishing

• cure for 40 seconds

GIC: fuji ix (will use this)

• self cured

• for protective restorations, endo access, base/ build up

• mixing time: 10 sec

• working time: 2 min

• setting time: 6 min

Resin Modified Glass Ionomer Cements - composition

• GIC are tooth colored but not strong enough → RMGIC introduced

resin composition: Methacrylate polyacid Hydroxyethylmethacrylate (HEMA) Activator/Initiators/Stabilizers

Resin Modified Glass Ionomer Cements- setting reactions

• 3-step reaction

• 1) acid base reaction

• 2) polymerization (combines many small molecules (monomers) into long chains (polymers))

• 3) Esterification 

RMGIC - Fuji 2 LC

• dual cured

• resin modified

• used for: protective restoration, class iii/ v base

• mixing time: 10 sec

• working time: 3 min 15 sec

• depth of cure: 1.8 mm

RMGIC- Fuji triage

• acid base reaction

• pink

• used for: protective restoration, sealant

• mixing time: 10 sec

• working time: 1 min 40 sec

• setting time: 2 min 30 sec

• shortest working time

cavity conditioner

• consists of 20% polyacrylic acid

• apply for 10 sec BEFORE GIC

• rinse, dry, but do not desicate

application of GIC:

1. cavity cleaning

2. activate (Unpack, shake, push button, Activate capsule in dispensing gun)

3. mix (7 sec)

4. dispense

Rank the fluoride release of GIC, RMGIC, and composite from most fluoride release to least

1. GIC

2. RMGIC

3. resin composite