Hydroxyapatite and Self-Assembling Peptide Matrix for Non-Oxidizing Tooth Whitening

The aim of this combined in vitro and in vivo study was to evaluate the efficacy of tooth whitening using a mixture of Self- Assembling Peptide Matrix (SAPM) and hydroxyapatite (HA).

The mixture was applied on stained bovine teeth, and the tooth color was measured using a spectrophotometer; mean changes in L*a*b values between measurements were expressed as DE. Additionally, the nature of the surface layer was investigated by ATRFTIR and EDX. The optical changes due to the additional surface layer were measured using a goniometer. Finally, a proof-of-concept clinical study was performed investigating the mixture of SAPM+HA.

The results verified that the SAPM remained on the tooth surface and acted as a temporary adhesive to attach the HA particles to the tooth surface. Further, the optical changes due to the additional surface layer indicated a diffuse reflection to be the origin of the optical whitening. Lastly, the mixture of SAPM+HA showed significant and visible whitening after one application, increasing throughout the first week of home application (DE = 4.9 ± 3.3) and remaining stable for 30 days (DE = 4.8 ± 3.6).

The combination of SAPM+HA particles caused optical whitening based on diffuse reflection by the HA particles on the tooth surface. The whitening effect and its magnitude observed in vitro were also seen in vivo.