Different effects of whitening treatment on natural teeth and teeth treated with Icon resin: an experimental study in vitro.

Background: It is quite common for white spots to develop on a tooth, due sometimes to a defective formation of the enamel layer, and sometimes to patches of demineralisation as a result of poor oral hygiene during orthodontic treatment with fixed braces. ICON DMG is currently the only noninvasive treatment for white spots. After a preliminary etching, it infiltrates the enamel, filling the spaces between the prisms with a resinous material that has a refraction coefficient very similar to that of healthy tooth enamel. The aim of this study was to test the efficacy of professional whitening procedures on teeth previously treated with ICON. The study hypothesis was that infiltration with ICON resin creates a barrier capable of preventing the bleaching action of the whitening agent.

Materials: White spots were artificially created on one half of the vestibular surface of 12 human teeth, while the other half was protected with a composite adhesive. The white spots were infiltrated with ICON and the protective adhesive was subsequently removed. A professional teeth whitening procedure was then completed on both halves of the teeth. A statistical analysis was performed to compare spectrophotometric recordings obtained before and after the ICON infiltration and teeth whitening procedures.

Conclusion: The whitening procedure modified the colour of the teeth on the half not infiltrated with ICON (p<0.05), but there was no statistically significant change in colour on the half infiltrated with ICON. The presence of the ICON resin seems to act as a partial barrier to the action of the whitening agent.