title: 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.
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 with Escherichia 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. The λ 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.
authors.affiliation: Odontostomatologic Laser Therapy Center, Via dell' Olivuzzo 162, 50143, Florence, Italy. dott.giannellimarco@gmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Giannelli
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Santa Maria alle Scotte University Hospital, Viale Bracci, Siena, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Landini
authors.affiliation: Odontostomatologic Laser Therapy Center, Via dell' Olivuzzo 162, 50143, Florence, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Materassi
authors.affiliation: Department of Experimental and Clinical Medicine - Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Flaminia
authors.initials: F
authors.lastname: Chellini
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Santa Maria alle Scotte University Hospital, Viale Bracci, Siena, Italy.|Department of Experimental and Clinical Medicine, Section of Critical Care and Specialistic Medicine, University of Florence, and 5Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Via San Damiano, 50134, Florence, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Antonelli
authors.affiliation: Department of Experimental and Clinical Medicine - Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Tani
authors.affiliation: Department of Experimental and Clinical Medicine - Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Zecchi-Orlandini
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Santa Maria alle Scotte University Hospital, Viale Bracci, Siena, Italy.|Department of Experimental and Clinical Medicine, Section of Critical Care and Specialistic Medicine, University of Florence, and 5Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Via San Damiano, 50134, Florence, Italy.|Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Via San Damiano, 50134, Florence, Italy.
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
authors.affiliation: Department of Experimental and Clinical Medicine - Section of Anatomy and Histology, Largo Brambilla 3, University of Florence, 50134, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Bani
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000528:radiation effects*; D018441:Biofilms / Q000187:drug effects*; D003666:Decontamination; D015921:Dental Implants / Q000382:microbiology*; D004926:Escherichia coli / Q000737:chemistry*; D005453:Fluorescence; D054023:Lasers, Semiconductor; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects / Q000528:radiation effects; D051379:Mice; D050296:Microbial Viability / Q000528:radiation effects; D000067996:RAW 264.7 Cells; D013211:Staphylococcus aureus / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*
chemical_list: D015921:Dental Implants; D008070:Lipopolysaccharides; C009495:titanium dioxide; D014025:Titanium
keywords: Dental implants; Diode laser; Lipopolysaccharide; Staphylococcus aureus; Titanium oxide