Effect of NaOCl and ToothMousse™ on hypomineralised enamel in MIH

Objectives: To evaluate the effect of: 1. 5% sodium hypochlorite (NaOCl) in removing proteins and on mechanical properties in MIH (Molar Incisor Hypomineralisation) enamel; 2.Tooth Mousse™ on hypomineralised enamel with and without treatment with 5% NaOCl. Methods: Seven teeth with MIH were sectioned mesiodistally/buccolingually (but not through the lesion) to obtain twelve samples and mounted in clear acrylic resin leaving the surface of hypomineralised enamel exposed. Enamel was polished following which the samples were divided into four study groups of three samples each: I. NaOCl treatment; II. NaOCl and Tooth Mousse™ treatment; III. No treatment; IV. Tooth Mousse™(TM) treatment. All the samples were subjected to nanoindentation and laser fluorescence (using DIAGNOdent) at the beginning of the experimental period, after use of NaOCl and/or TM and following storage in Hank's solution for 30 days. Results: Application of NaOCl appeared to result in a decrease in both the protein content and mechanical properties of MIH enamel. Subsequent storage in Hank's solution and use of TM did not result in an improvement in the mechanical properties. Storage in Hank's solution alone resulted in an unexpected improvement in the mechanical properties. Use of TM alone without treatment with NaOCl also resulted in an improvement in the mechanical properties. These results were also associated with changes in the laser fluorescence of the enamel. Conclusions: A single application of NaOCl appeared to remove protein from the surface of hypomineralised enamel, resulting in reduction of its mechanical properties. Application of TM daily for 30 days after NaOCl treatment did not result in an improvement of the mechanical properties of hypomineralised enamel while TM application alone did result in an improvement in the mechanical properties.