Tooth-whitening activity of a novel home-bleaching system utilising thermal diffusion : a multifactorial simultaneous evaluation of efficacy at cervical, body and incisal tooth sites

Introduction The ability of a thermal diffusion system (TDS) to promote the tooth-whitening actions of a bleaching gel/bleaching activator combination product (containing a final hydrogen peroxide (H2O2) content of 10.0% (w/v)) towards discoloured 'smile-zone' teeth was examined. Methods Fifty teeth in 15 participants aged 18-62 years were investigated. The CIE tooth shade parameters L*, a* and b*, together with Vitapan shade scores (VSSs), were simultaneously recorded at three separate tooth areas (cervical, body and incisal sites) with a novel spectrophotometric monitoring system before treatment, and also at 14 days after completion of a 10-day treatment period in which the product was applied 'at-home' (twice daily). Results The tooth-whitening treatment administered gave rise to extremely significant increases in L*, and decreases in the a* and b* shade parameters for each of the tooth areas investigated (p <10−10). Post-treatment mean decreases in the VSS values were 8.26, 9.70 and 9.14 for the cervical, body and incisal areas respectively (p <10−8 in each case). Mean ΔE values determined post-treatment were also very highly significant for each tooth region examined (p <10−10 in each case). Conclusions The tooth-whitening system tested exerted extremely powerful bleaching actions in all tooth areas investigated. The order of tooth-whitening effectiveness was body > incisal > cervical for Δb* and ΔE, and incisal > body > cervical for Δa* and ΔL*, and this may reflect the TDS's ability to promote the penetration of H2O2 to intrinsic stain sites