Training in the use of the water jet and cold atmospheric plasma jet for the decontamination of dental implants.

OBJECTIVES: Clinical trials testing new devices require prior training on dummies to minimize the "learning curve" for patients. Dentists were trained using a novel water jet device for mechanical cleaning of dental implants and with a novel cold plasma device for surface functionalisation during a simulated open flap peri-implantitis therapy. The hypothesis was that there would be a learning curve for both devices. MATERIALS AND METHODS: 11 dentists instrumented 44 implants in a dummy-fixed jaw model. The effect of the water jet treatment was assessed as stain removal and the effect of cold plasma treatment as surface wettability. Both results were analysed using photographs. To improve treatment skills, each dentist treated four implants and checked the results immediately after the treatment as feedback. RESULTS: Water jet treatment significantly improved from the first to the second implant from 62.7% to 75.3% stain removal, with no further improvement up to the fourth implant. The wettability with cold plasma application reached immediately a high level at the first implant and was unchanged to the 4th implant (mean scores 2.7 out of 3). CONCLUSION: A moderate learning curve was found for handling of the water jet but none for handling of the cold plasma. CLINICAL RELEVANCE: Scientific rational for study: Two new devices were developed for peri-implantitis treatment (Dental water jet, cold plasma). Dentists were trained in the use of these devices prior to the trial to minimize learning effects. PRINCIPAL FINDINGS: Experienced dentists learn the handling of the water jet very rapidly and for cold plasma they do not need much training. PRACTICAL IMPLICATIONS: A clinical study is in process. When the planned clinical study will be finished, we will find out, if this dummy head exercise really minimised the learning curve for these devices.

In-Vitro Biofilm Removal Efficacy Using Water Jet in Combination with Cold Plasma Technology on Dental Titanium Implants.

Peri-implantitis-associated inflammation can lead to bone loss and implant failure. Current decontamination measures are ineffective due to the implants' complex geometry and rough surfaces providing niches for microbial biofilms. A modified water jet system (WaterJet) was combined with cold plasma technology (CAP) to achieve superior antimicrobial efficacy compared to cotton gauze treatment. Seven-day-old multi-species-contaminated titanium discs and implants were investigated as model systems. The efficacy of decontamination on implants was determined by rolling the implants over agar and determining colony-forming units supported by scanning electron microscopy image quantification of implant surface features. The inflammatory consequences of mono and combination treatments were investigated with peripheral blood mononuclear cell surface marker expression and chemokine and cytokine release profiles on titanium discs. In addition, titanium discs were assayed using fluorescence microscopy. Cotton gauze was inferior to WaterJet treatment according to all types of analysis. In combination with the antimicrobial effect of CAP, decontamination was improved accordingly. Mono and CAP-combined treatment on titanium surfaces alone did not unleash inflammation. Simultaneously, chemokine and cytokine release was dramatically reduced in samples that had benefited from additional antimicrobial effects through CAP. The combined treatment with WaterJet and CAP potently removed biofilm and disinfected rough titanium implant surfaces. At the same time, non-favorable rendering of the surface structure or its pro-inflammatory potential through CAP was not observed.

Reliability of probing depth assessments at healthy implant sites and natural teeth.

AIM: To evaluate the intra- and inter-examiner reliability in the assessment of probing depth (PD) measurements at healthy dental implant sites and periodontally healthy natural teeth. MATERIALS AND METHODS: Five patients exhibiting 21 dental implants were enrolled in the study. Eight experienced examiners performed duplicate PD measurements at six sites of all implants and of preselected natural teeth. Intra-examiner accuracy was estimated using intra-examiner correlation coefficients (ICCs) with 95% confidence intervals (CI). A gold standard (GS) examiner was set. Inter-examiner accuracy compared to the GS examiner was assessed using pairwise inter-examiner ICCs. RESULTS: The intra-examiner ICC ranged from 0.759 (95% CI, 0.692-0.812) to 0.863 (95% CI, 0.826-0.892) for the measurements at teeth and from 0.712 (95% CI, 0.580-0.800) to 0.841 (95% CI, 0.774-0.888) for the PDs assessed at implants. The inter-examiner ICCs for tooth measurements varied from 0.197 (95% CI, - 0.280 to 0.511) to 0.791 (95% CI, 0.560-0.892). The corresponding values for the assessments at implants varied from 0.576 (95% CI, 0.286-0.734) to 0.794 (95% CI, 0.708-0.855). CONCLUSIONS: The intra- and inter-examiner reproducibility of repeated PD measurements assessed by experienced examiners tended to be higher for the measurements at periodontally healthy teeth compared to healthy dental implant sites. CLINICAL RELEVANCE: Experienced examiners demonstrated a higher degree of reliability of probing measurements around teeth compared to dental implants.

Efficiency of biofilm removal by combination of water jet and cold plasma: an in-vitro study.

BACKGROUND: Peri-implantitis therapy is a major problem in implantology. Because of challenging rough implant surface and implant geometry, microorganisms can hide and survive in implant microstructures and impede debridement. We developed a new water jet (WJ) device and a new cold atmospheric pressure plasma (CAP) device to overcome these problems and investigated aspects of efficacy in vitro and safety with the aim to create the prerequisites for a clinical pilot study with these medical devices. METHODS: We compared the efficiency of a single treatment with a WJ or curette and cotton swab (CC) without or with adjunctive use of CAP (WJ + CAP, CC + CAP) to remove biofilm in vitro from rough titanium discs. Treatment efficacy was evaluated by measuring turbidity up to 72 h for bacterial re-growth or spreading of osteoblast-like cells (MG-63) after 5 days with scanning electron microscopy. With respect to application safety, the WJ and CAP instruments were examined according to basic regulations for medical devices. RESULTS: After 96 h of incubation all WJ and CC treated disks were turbid but 67% of WJ + CAP and 46% CC + CAP treated specimens were still clear. The increase in turbidity after WJ treatment was delayed by about 20 h compared to CC treatment. In combination with CAP the cell coverage significantly increased to 82% (WJ + CAP) or 72% (CC + CAP), compared to single treatment 11% (WJ) or 10% (CC). CONCLUSION: The newly developed water jet device effectively removes biofilm from rough titanium surfaces in vitro and, in combination with the new CAP device, biologically acceptable surfaces allow osteoblasts to grow. WJ in combination with CAP leads to cleaner surfaces than the usage of curette and cotton swabs with or without subsequent plasma treatment. Our next step will be a clinical pilot study with these new devices to assess the clinical healing process.

Minimal synthetic cells to study integrin-mediated adhesion.

To shed light on cell-adhesion-related molecular pathways, synthetic cells offer the unique advantage of a well-controlled model system with reduced molecular complexity. Herein, we show that liposomes with the reconstituted platelet integrin αIIb ß3 as the adhesion-mediating transmembrane protein are a functional minimal cell model for studying cellular adhesion mechanisms in a defined environment. The interaction of these synthetic cells with various extracellular matrix proteins was analyzed using a quartz crystal microbalance with dissipation monitoring. The data indicated that integrin was functionally incorporated into the lipid vesicles, thus enabling integrin-specific adhesion of the engineered liposomes to fibrinogen- and fibronectin-functionalized surfaces. Then, we were able to initiate the detachment of integrin liposomes from these surfaces in the presence of the peptide GRGDSP, a process that is even faster with our newly synthesized peptide mimetic SN529, which specifically inhibits the integrin αIIb ß3 .

Does perthionitrite (SSNO(-)) account for sustained bioactivity of NO? A (bio)chemical characterization.

Hydrogen sulfide (H2S) and nitric oxide (NO) are important signaling molecules that regulate several physiological functions. Understanding the chemistry behind their interplay is important for explaining these functions. The reaction of H2S with S-nitrosothiols to form the smallest S-nitrosothiol, thionitrous acid (HSNO), is one example of physiologically relevant cross-talk between H2S and nitrogen species. Perthionitrite (SSNO(-)) has recently been considered as an important biological source of NO that is far more stable and longer living than HSNO. In order to experimentally address this issue here, we prepared SSNO(-) by two different approaches, which lead to two distinct species: SSNO(-) and dithionitric acid [HON(S)S/HSN(O)S]. (H)S2NO species and their reactivity were studied by (15)N NMR, IR, electron paramagnetic resonance and high-resolution electrospray ionization time-of-flight mass spectrometry, as well as by X-ray structure analysis and cyclic voltammetry. The obtained results pointed toward the inherent instability of SSNO(-) in water solutions. SSNO(-) decomposed readily in the presence of light, water, or acid, with concomitant formation of elemental sulfur and HNO. Furthermore, SSNO(-) reacted with H2S to generate HSNO. Computational studies on (H)SSNO provided additional explanations for its instability. Thus, on the basis of our data, it seems to be less probable that SSNO(-) can serve as a signaling molecule and biological source of NO. SSNO(-) salts could, however, be used as fast generators of HNO in water solutions.

Crystal structure of bis-(µ2-4-tert-butyl-2-formyl-phenolato)-1:2κ(3) O (1),O (2):O (1);3:4κ(3) O (1),O (2):O (1)-bis-(4-tert-butyl-2-formyl-phenolato)-2κ(2) O (1),O (2);4κ(2) O (1),O (2)-di-µ3-methoxido-1:2:3κ(3) O;1:3:4κ(3) O-di-µ2-methoxido-1:4κ(2) O;2:3κ(2) O-tetra-copper(II).

The structure of the title compound, [Cu4(CH3O)4(C11H13O2)4], consists of dimeric dinuclear copper(II) complexes oriented around a centre of inversion. Within each dinuclear fragment, the two Cu(II) atoms are in a distorted square-planar coordination sphere. Two neighbouring fragments are linked by four apical Cu-O contacts, yielding an overall square-pyramidal coordination environment for each of the four Cu(II) atoms. The mol-ecules are arranged in layers parallel to (101). Non-classical C-H⋯O hydrogen-bonding inter-actions are observed between the layers.