CeO nanorods are functional mimics of natural haloperoxidases. They catalyze the oxidative bromination of phenol red to bromophenol blue and of natural signaling molecules involved in bacterial quorum sensing. Laboratory and field tests with paint formulations containing 2 wt% of CeO nanorods show a reduction in biofouling comparable to Cu O, the most typical biocidal pigment.

Even at low energy densities, the Er:YAG laser has a high bactericidal potential on common implant surfaces. Clinical studies are justified to evaluate the applicability and efficacy of the Er:YAG laser in the treatment of peri-implantitis.

Titanium platelets with a sand-blasted and acid-etched surface were coated with bovine serum albumin and incubated with a suspension of Porphyromonas gingivalis (ATCC 33277). Four groups with a total of 48 specimens were formed. Laser irradiation of the specimens (n = 12) was performed on a computer-controlled XY translation stage at pulse energy 60 mJ and frequency 10 pps. Twelve specimens were treated with an air powder system. After the respective treatment, human gingival fibroblasts were incubated on the specimens. The proliferation rate was determined by means of fluorescence activity of a redox indicator (Alamar Blue Assay) which is reduced by metabolic activity related to cellular growth. Proliferation was determined up to 72 h. Contaminated and non-treated as well as sterile specimens served as positive and negative controls. Proliferation activity was significantly (Mann-Whitney U-test, P < 0.05) reduced on contaminated and non-treated platelets when compared to sterile specimens. Both on laser as well as air powder-treated specimens, cell growth was not significantly different from that on sterile specimens. Air powder treatment led to microscopically visible alterations of the implant surface whereas laser-treated surfaces remained unchanged. Both air powder and Er : YAG laser irradiation have a good potential to remove cytotoxic bacterial components from implant surfaces. At the irradiation parameters investigated, the Er : YAG laser ensures a reliable decontamination of implants in vitro without altering surface morphology.

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Numerous studies have confirmed the potential of erbium laser irradiation for increasing the acid resistance of dental enamel. The objective of the present paper was to investigate the effect of subablative erbium laser irradiation on the structure and acid resistance of dental enamel by means of confocal laser scanning microscopy (CLSM). To this end, 12 samples of human dental enamel were irradiated with subablative energy densities (Φ) of an Er:YAG (λ = 2.94 µm, Φ = 6 J/cm²) and an Er:YSGG laser (λ = 2.79 µm, Φ = 8 J/cm²). The enamel surfaces of 6 samples were polished prior to irradiation. The remaining 6 samples were left intact (without polishing procedures) and, in the further course of the study, they were subjected to 1-week in situ demineralisation. All irradiated test surfaces were assigned a control surface on the same sample. The changes following laser irradiation and the in situ wearing time were assessed qualitatively using a confocal laser scanning microscope. The irradiation of dental enamel with subablative erbium laser irradiation produces fine cracks in the enamel surface. These cracks act as starting points for acid attack and favour deep demineralisation. These changes reduce or eliminate the positive effect of subablative erbium laser irradiation observed in connection with caries-preventive use. The clinical use of subablative erbium laser irradiation to prevent caries would appear not to make sense under the conditions studied.