4. Class III Composite Restoration

amalgam composites are common in

lingual pits of elder patients

Indications for composite restoration

To replace composite or amalgam restorations

Contraindications

When the tooth cannot be adequately isolated

Advantages

- Esthetics - Tooth preparation less complex
- Preserve tooth structure
- Used almost universally
- Increase the strength of remaining tooth structure
- Repairable

Disadvantages

Polymerization shrinkage can create gaps
- More technique-sensitive
- Lower fracture toughness than indirect restorations
- Possible of greater wear

in real life preps (when referring to smoothness and size of the prep)

caries dictates the shape of the prep. floors and walls may not always be smooth, but the caries should always be removed

when should amalgam be removed

if the patient desires it or if caries formed around it

why does composite make the tooth stronger?

it is chemically bonded to the tooth

adhesive and cohesive fractures

A: during polymerization between the tooth and adhesive or adhesive and the tooth

C: in dentin bonding by itself or the composite

reasons to replace old composite

leakage, discoloration, secondary caries

Class III Composite restorations steps

Diagnosis
Checking the occlusion
Anesthesia and prophylaxis
Tooth color selection Field isolation
Cavity preparation

Proximal Caries Lesions

Caries in enamel Caries in dentin
Non-cavitated caries Cavitated caries Inactive caries
Active caries

refraction index of water, air and enamel

W: 1.33
A: 1
E: 1.62 (water and enamels close RI is why you cant see caries when the tooth is wet. closer the RI is between organic particles and inorganic filler, the better the light penetration and shade)