The effects of diode laser on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide adherent to titanium oxide surface of dental implants. An in vitro study. Issue 8 (November 2016)

• Record Type: Journal Article
• Authors: Giannelli, Marco; Landini, Giulia; Materassi, Fabrizio; Chellini, Flaminia; Antonelli, Alberto; Tani, Alessia; Zecchi-Orlandini, Sandra; Rossolini, Gian; Bani, Daniele
• Is Part Of: Lasers in medical science. Volume 31:Issue 8(2016)
• Page Start: 1613
• Page End: 1619
• Publication Date: 2016-11
• Subjects: Diode laser -- Dental implants -- Titanium oxide -- Staphylococcus aureus -- Lipopolysaccharide; Lasers in medicine -- Periodicals; 610.28
• DOI: 10.1007/s10103-016-2025-5
• Languages: English
• ISSNs: 0268-8921

Abstract

Abstract Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This in vitro study aims at providing the experimental basis for possible use of diode laser (λ 808 nm) in the treatment of peri-implantitis.Staphylococcus aureus biofilm was grown for 48 h on titanium discs with porous surface corresponding to the bone-implant interface and then irradiated with a diode laser (λ 808 nm) in noncontact mode with airflow cooling for 1 min using a Ø 600-μm fiber. Setting parameters were 2 W (400 J/cm2 ) for continuous wave mode; 22 μJ, 20 kHz, 7 μs (88 J/cm2 ) for pulsed wave mode. Bactericidal effect was evaluated using fluorescence microscopy and counting the residual colony-forming units. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, the titanium discs were coated withEscherichia coli lipopolysaccharide (LPS), laser-irradiated and seeded with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Diode laser irradiation in both continuous and pulsed modes induced a statistically significant reduction of viable bacteria and nitrite levels. These results indicate that in addition to its bactericidal effect laser irradiation can also inhibit LPS-induced macrophage activation and thus blunt the inflammatory response. Theλ 808-nm diode laser emerges as a valuable tool for decontamination/detoxification of the titanium implant surface and may be used in the treatment of peri-implantitis.