Comparative effects of hydrogen peroxide- and indocyanine green- mediated photodynamic therapy on the viability and adhesion of human gingival fibroblasts to root cementum: An invitro study.

OBJECTIVES: This study assessed the effect of photodynamic therapy (PDT) with hydrogen peroxide (H2O2) and indocyanine green (ICG) on the viability and adhesion of human gingival fibroblasts (HGFs) to root cementum. MATERIALS AND METHODS: In this in vitro study, 64 root sections of extracted molar and premolar teeth were randomly divided into 4 groups (n=16) of (I) scaling and root planing (SRP; control), (II) SRP+40% citric acid, (III) SRP+H2O2+ laser irradiation (980 nm, 2.5 W), and (IV) SRP+ICG+ laser irradiation (808 nm, 200 mW). HGFs were cultured at a density of 5×104 cells. Cell viability was assessed after 24, 48, and 72 hours while cell adhesion was evaluated after 24 hours using the methyl thiazolyl tetrazolium (MTT) assay. Comparisons were made using ANOVA and Tukey HSD test (alpha=0.05). RESULTS: The H2O2 group showed the highest cell viability at all time points. The ICG group showed the highest cell adhesion, followed by the H2O2 group. The citric acid group showed the lowest cell adhesion, and moderate cell viability while the control group had the poorest performance. The difference in both cell viability and adhesion was significant among the groups (P<0.05), with the H2O2 group being significantly superior in cell viability, and the ICG group being significantly superior in cell adhesion (P<0.05). CONCLUSION: PDT specially with H2O2 significantly enhanced the viability of HGFs under in vitro conditions. H2O2 provided a suitable environment for cell proliferation while ICG enhanced cell adhesion.