RESUMEN
BACKGROUND: Invasion of periodontal pockets with persistent microorganisms and subsequent development of a biofilm are the main cause of periodontal infections. In severe cases, additional use of antibiotics to the standard therapy of scaling and root planing (SRP), is necessary, but the use of antibiotics may lead to resistance. As an alternative, the combination of SRP and adjunct photodynamic therapy (PDT) is applied in the treatment of periodontal infections to improve periodontal therapy. The aim of this study was to determine possible side effects of PDT on human gingival fibroblasts (GF) and human osteoblasts (OB). METHODS: GF and OB were either untreated or treated with methylene blue (MB) only, with MB and subsequently irradiation with a soft laser (PDT) or irradiated with a soft laser only. All cells were analyzed for viability using the MTT test, migration capacity using Boyden chambers, and the scratch wound assay. RESULTS: Viability and migration capacity of GF and OB were not affected by PDT (for GF: p = 0.48, for OB: p = 0.08 compared to control group) whereas soft laser irradiation only improved cell viability and migration and MB treatment only reduced cell viability and migration. After 72 hours of incubation of both GF and OB, the gaps were almost closed. CONCLUSIONS: In vitro, PDT did not affect viability and migration capacity of GF and OB whereas soft laser treatment only had a positive effect on GF and OB. Therefore, PDT seems to be a safe method in the treatment of periodontal infections without significant side effects.