[Laboratory evaluation of tooth whitening agents in hydroxyapatite samples].

The paper presents laboratory model for evaluation of the effectiveness of tooth whitening agents on pure and technical hydroxyapatite (HAP) samples. HAP samples were exposed in distilled water, and colour measurements were taken after coloration in tea extract and using of "Blend-a-med delicate bleaching" ("Procter & Gamble", Germany) toothpaste. The proposed laboratory model allows imitating discoloration by food dye (tea) and measure the whitening toothpaste effect by significant change in colour characteristics in the CIE L*a*b* system.