Teeth bleaching has different effects on different types of teeth, teeth surfaces, restorations and other materials. It can bleach the teeth but not the restorations. These effects are discussed as under:

1. Effect on Enamel  

Carbamide peroxide decreases hardness of the enamel.

2. Effect on Dentine

It can cause uniform color change.

3. Effect on Pulp 

The teeth bleaching agents penetrates from enamel and dentine into the pulp. Thus will cause – slow decrease in blood flow (pulpal), and pulpal blood vessels occlusion.

4. Effects on Cementum 

Home bleaching materials or agents do not affect cementum but there are patients where due to intracoronal bleaching by 30–35% hydrogen peroxide causes cervical resorption and external root resorption.

5. Effect on Restorative Materials  

On Composites: surface roughness & gives etched appearance, decrease in tensile strength, increase in surface hardness, and increase in micro leakage.

6. On Other Materials: no effect on gold restoration, in case of amalgam it causes changes in micro structure occurs, in glass ionomers there is alteration of the matrix, in interim restorative material due to hydrogen peroxide there is cracking of the restoration, the crowns made from methyl methacrylate they undergo color change and turns orange.

Effect on Mucosa 

Hydrogen Peroxide (30 – 35 %) causes mucosal irritation & burning sensation.

Causes Gentotoxicity & Carcinogenicity

Toxicity can result if taken in higher concentration.