with limited evidence based information in literature about using Strawberry extract for teeth bleaching in patients with extrinsic staining , it is beneficial to evaluate this new material using a randomized controlled clinical trial to test the null hypothesis that this extract will have the same effect as Hydrogen peroxide regarding the bleaching effect and hypersensitivity.

The whitening effect of strawberry is due to the presence of malic acid, which acts as a natural astringent to remove surface discoloration. The ellagic acid content in strawberry is ranging from 0.43 to 4.64 mg/g dry weight. The more amount of ellagic acid will produce more potential OH clusters as a powerful oxidizer thus make the more effective bleaching process. Ellagic acid releases the OH and H radicals which will react with the tooth enamel organic molecules and disrupt the electron conjugation, as well as changing the energy absorption in the tooth enamel organic molecules to form smaller organic molecules with a lighter color. Ellagic acid has an OH cluster, not COOH cluster like any other acids. The electronegativity of the OH group will be easier to break and react with the organic molecules of tooth enamel.

Inclusion Criteria:

Participant inclusion criteria:

1. At least 18 years old.
2. Good general and oral health.
3. six present maxillary anterior teeth.

Tooth inclusion criteria:

1. yellowing of teeth due to age.

2. stains due to coffee or tea.

3. light tetracycline stain.

   • Exclusion Criteria:

participant exclusion criteria:

1. patients undergoing radiotherapy or chemotherapy.
2. Pregnant females or breast feeders.
3. Bruxism and patients who reported tooth sensitivity.

Tooth exclusion criteria:

1. Hypoplastic enamel.
2. carious lesion.
3. sensitive recession area or sensitive tooth.
4. Amalgam staining.
5. Non vital tooth.
6. Discolration due to pulp trauma or necrosis.
7. presence of non carious cervical lesion.