In-vivo colour stability of enamel after ICON® treatment at 6 years of follow-up: a prospective single center study

Objectives: This in-vivo clinical study provides subjective and objective documentation on colour stability of enamel after resin infiltration at a mean observation time of six years after treatment. Methods: 76 teeth previously treated with ICON® due to hypomineralized lesions of enamel were recalled for a follow-up at ………(………..). Colour stability was assessed: i) subjectively by patients using FDI-colour matching criteria; ii) objectively by calculating CIEDE2000 colour differences between the affected/treated and sound enamel in each tooth at T0 (baseline), T1 (one year) and T2 (six years) based on spectrophotometric data. Analysis of correlation between FDI and CIEDE2000 data was performed. Results: Two teeth were lost to follow-up prior to 72 months. No unwanted effects were reported by patients. Number of FDI scores 1 and 2 were 13.5%, 90.6% and 93.2% at T0, T1 and T2, respectively. ΔE00 was evaluated at 6.8 (SD3.8) at T0. ΔE00 was 5.8 (SD3.1) between T0 and T1 and 1.3 (SD0.6) between T1 and T2. ΔE00 reduction (T1-T0) was significantly but only fairly correlated with FDI scores at any follow-up. Conclusions: This study shows that caries infiltration satisfactorily masks aesthetically relevant lesions after longer follow-up. Subjective and objective outcomes showed a fair correlation mainly for the initial masking effect. Clinical significance: This prospective clinical trial demonstrates the excellent subjective and objective colorimetric stability of enamel treated with ICON® 6 years after treatment.