Biofilm related to dental implants

Cytotoxicity of dental cement on soft tissue associated with dental implants at different time intervals

Background

To investigate and compare the effect of four commercially used dental cement at 24 hours, 48 hours,72 hours (h) and 6 days on the cellular response of human gingival fibroblast (HGF).

Methods

3 cement pellet samples were made for each 4-test cement (n=12). The cement used for this study were zinc phosphate (ZP), zinc oxide non-eugenol (ZOE), RelyX U200 (RU200), and glass ionomer cement (GIC). The cytotoxicity of peri-implant tissues was investigated using one commercial cell line. All processing was done following International Organization for Standardization (ISO) methods 10993-5 and 10993-12 (MTT assay Test). Cell cultures without dental cement were considered as control. Standard laboratory procedures were followed to permit cell growth and confluence over 48 hrs after sub-cultivation. Before being subjected to analysis, the cells were kept in direct contact with the cement samples for the suggested time period. To validate the results the specimens were tested three times each. Cell death and inhibition of cell growth were measured quantitatively. Results were analyzed using 1-way ANOVA (a=0.05) followed by Tukey B post hoc test.

Results

The study showed the dental cement test material was cytotoxic. ZOE, ZP, GIC, and RU200 were cytotoxic in decreasing order, respectively, significantly reducing cell viability after exposure to HGF (p <0.001).

Conclusions

Within the limitations of this in-vitro cellular study, results indicated that HGF were vulnerable to the test the dental cement. The highest cytotoxicity was observed in ZOE, followed by ZP, GIC, and RU200.

Cytotoxicity of dental cement on soft tissue associated with dental implants at different time intervals

Background: To investigate and compare the effect of four commercially used dental cement at 24 hours, 48 hours,72 hours (h) and 6 days on the cellular response of human gingival fibroblast (HGF). Methods: 3 cement pellet samples were made for each 4-test cement (n=12). The cement used for this study were zinc phosphate (ZP), zinc oxide non-eugenol (ZOE), RelyX U200 (RU200), and glass ionomer cement (GIC). The cytotoxicity of peri-implant tissues was investigated using one commercial cell line. All processing was done following International Organization for Standardization (ISO) methods 10993-5 and 10993-12 (MTT assay Test). Cell cultures without dental cement were considered as control. Standard laboratory procedures were followed to permit cell growth and confluence over 48 hrs after sub-cultivation. Before being subjected to analysis, the cells were kept in direct contact with the cement samples for the suggested time period. To validate the results the specimens were tested three times each. Cell death and inhibition of cell growth were measured quantitatively. Results were analyzed using 1-way ANOVA (a=0.05) followed by Tukey B post hoc test. Results: The study showed the dental cement test material was cytotoxic. ZOE, ZP, GIC, and RU200 were cytotoxic in decreasing order, respectively, significantly reducing cell viability after exposure to HGF (p <0.001). Conclusions: Within the limitations of this in-vitro cellular study, results indicated that HGF were vulnerable to the test the dental cement. The highest cytotoxicity was observed in ZOE, followed by ZP, GIC, and RU200.

Anti-biofilm effect of salivary histatin 5 on Porphyromonas gingivalis

This study aimed to investigate the effects of salivary histatin 5 (Hst5) on Porphyromonas gingivalis (P. gingivalis) biofilms in vitro and in vivo and the possible mechanisms. In in vitro experiments, P. gingivalis biomass was determined by crystal violet staining. Polymerase chain reaction, scanning electron microscopy, and confocal laser scanning microscopy were used to determine the Hst5 concentration. A search for potential targets was performed using transcriptomic and proteomic analyses. In vivo experimental periodontitis was established in rats to evaluate the effects of Hst5 on periodontal tissues. Experimental results showed that 25 µg/mL Hst5 effectively inhibited biofilm formation, and increased concentrations of Hst5 increased the inhibitive effect. Hst5 might bind to the outer membrane protein RagAB. A combination of transcriptomic and proteomic analyses revealed that Hst5 could regulate membrane function and metabolic processes in P. gingivalis, in which RpoD and FeoB proteins were involved. In the rat periodontitis model, alveolar bone resorption and inflammation levels in periodontal tissues were reduced by 100 µg/mL Hst5. This study showed that 25 µg/mL Hst5 inhibited P. gingivalis biofilm formation in vitro by changing membrane function and metabolic process, and RpoD and FeoB proteins might play important roles in this process. Moreover, 100 µg/mL Hst5 inhibited periodontal inflammation and alveolar bone loss in rat periodontitis via its antibacterial and anti-inflammatory effects. KEY POINTS: • Anti-biofilm activity of histatin 5 on Porphyromonas gingivalis was investigated. • Histatin 5 inhibited Porphyromonas gingivalis biofilm formation. • Histatin 5 showed inhibitory effects on the occurrence of rat periodontitis.

The Impact of Smoking on Peri-implant Microbiota: A Systematic Review

OBJECTIVES

Peri-implantitis is associated with bacterial plaque biofilms and with patients who have a history of periodontitis. Smoking is a risk factor for periodontitis, but the relationship between smoking and peri-implantitis is unclear. The aim of this systematic review was to assess evidence ascertaining the relationship between smoking and peri-implant microbiota.

DATA SOURCES

An electronic search was conducted in the MEDLINE/PubMed, Embase and Scopus® databases in duplicate up to January 2023 without language restrictions. Studies were considered eligible for inclusion if they involved evaluation of the peri-implant microbiota of smokers and nonsmokers. Methodological quality was assessed with the adapted Newcastle-Ottawa scale.

STUDY SELECTION

Fourteen studies were identified for inclusion in the present study, and 85.7% of the studies were defined as medium to high methodological quality. Overall, the evidence presented in this review was limited to medium to high methodological quality. The data indicates that significantly higher frequencies of anaerobic pathogens are detectable in healthy peri-implant tissues of smokers. A lower diversity of microbiota was observed in healthy peri-implant sites of smokers. In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species.

CONCLUSIONS

The composition of peri-implant microbiota may be influenced by smoking. More studies are needed to determine the impact of smoking on peri-implant microbiota.

CLINICAL SIGNIFICANCE

In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species. The composition of peri-implant microbiota may be influenced by smoking.

Magnetically Driven Self-Degrading Zinc-Containing Cystine Microrobots for Treatment of Prostate Cancer

Prostate cancer is the most commonly diagnosed tumor disease in men, and its treatment is still a big challenge in standard oncology therapy. Magnetically actuated microrobots represent the most promising technology in modern nanomedicine, offering the advantage of wireless guidance, effective cell penetration, and non-invasive actuation. Here, new biodegradable magnetically actuated zinc/cystine-based microrobots for in situ treatment of prostate cancer cells are reported. The microrobots are fabricated via metal-ion-mediated self-assembly of the amino acid cystine encapsulating superparamagnetic Fe₃ O₄ nanoparticles (NPs) during the synthesis, which allows their precise manipulation by a rotating magnetic field. Inside the cells, the typical enzymatic reducing environment favors the disassembly of the aminoacidic chemical structure due to the cleavage of cystine disulfide bonds and disruption of non-covalent interactions with the metal ions, as demonstrated by in vitro experiments with reduced nicotinamide adenine dinucleotide (NADH). In this way, the cystine microrobots served for site-specific delivery of Zn²⁺ ions responsible for tumor cell killing via a "Trojan horse effect". This work presents a new concept of cell internalization exploiting robotic systems' self-degradation, proposing a step forward in non-invasive cancer therapy.

In Vivo Biofilm Formation on Novel PEEK, Titanium, and Zirconia Implant Abutment Materials

The formation of biofilms on the surface of dental implants and abutment materials may lead to peri-implantitis and subsequent implant failure. Recently, innovative materials such as polyether-ether-ketone (PEEK) and its modifications have been used as abutment materials. However, there is limited knowledge on microbial adhesion to PEEK materials. The aim of this in vivo study was to investigate biofilm formation on the surface of conventional (titanium and zirconia) and PEEK implant abutment materials. Split specimens of titanium, zirconia, PEEK, and modified PEEK (PEEK-BioHPP) were manufactured, mounted in individual removable acrylic upper jaw splints, and worn by 20 healthy volunteers for 24 h. The surface roughness was determined using widefield confocal microscopy. Biofilm accumulation was investigated by fluorescence microscopy and quantified by imaging software. The surface roughness of the investigated materials was <0.2 µm and showed no significant differences between the materials. Zirconia showed the lowest biofilm formation, followed by titanium, PEEK, and PEEK-BioHPP. Differences were significant (p < 0.001) between the investigated materials, except for the polyether-ether-ketones. Generally, biofilm formation was significantly higher (p < 0.05) in the posterior region of the oral cavity than in the anterior region. The results of the present study show a material-dependent susceptibility to biofilm formation. The risk of developing peri-implantitis may be reduced by a specific choice of abutment material.

Comparison of In Vitro Biofilm Formation on Titanium and Zirconia Implants

Background

Peri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants.

Methods

Biofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants.

Results

Three-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm.

Conclusion

While early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.

Bacteriostatic Poly Ethylene Glycol Plasma Coatings for Orthodontic Titanium Mini-Implants

Titanium mini-implants are used as anchorage for orthodontic tooth movements. However, these implants present problems due to the infection of surrounding tissues. The aim of this work was to obtain a polyethylene glycol (PEG) layer by plasma in order to achieve a bacteriostatic surface. Titanium surfaces were activated by argon plasma and, after, by PEG plasma with different powers (100, 150 and 200 W) for 30 and 60 min. The roughness was determined by white light interferometer microscopy and the wettability was determined by the contact angle technique. Surface chemical compositions were characterized by X-ray photoelectron spectroscopy (XPS) and cytocompatibility and cell adhesion studies were performed with fibroblast (hFFs) and osteoblast (SAOS-2) cells. Bacterial cultures with Spectrococcus Sanguinis and Lactobacillus Salivarius were performed, and bacterial colonization was determined. The results showed that plasma treatments do not affect the roughness. Plasma makes the surfaces more hydrophilic by decreasing the contact angles from 64.2° for titanium to 5.2° for argon-activated titanium, with values ranging from 12° to 25° for the different PEG treatments. The plasma has two effects: the cleaning of the surface and the formation of the PEG layer. The biocompatibility results were, for all cases, higher than 80%. The polymerization treatment with PEG reduced the adhesion of hFFs from 7000 to 6000 and, for SAOS-2, from 14,000 to 6500, for pure titanium and those treated with PEG, respectively. Bacterial adhesion was also reduced from 600 to 300 CFU/mm² for Spetrococcuns Sanguinis and from 10,000 to 900 CFU/mm² for Lactobacillus Salivarius. The best bacteriostatic treatment corresponded to PEG at 100 W and 30 s. As a consequence, the PEG coating would significantly prevent the formation of bacterial biofilm on the surface of titanium mini-implants.

New and innovative biomaterials, techniques and therapy concepts: Biologization in maxillofacial surgery, oral surgery and dentistry is in full swing. PRF, PRGF, PRP, blood plasma-stabilized augmentations, supplementation of micronutrients and vitamins - what opportunities do such "biological" approaches actually offer? We introduce them here

Biomaterials of natural origin have recently gained increasing attention in the field of dental implantology. The requirements for such materials, however, are very high. In addition to high clinical efficiency in tissue regeneration, wound healing should be demonstrably positively influenced. The translational division for regenerative orofacial medicine of the Clinic and Polyclinic for Oral and Maxillofacial Surgery of the University Medical Center Hamburg-Eppendorf (UKE) is examining this research topic by investigating which innovative treatment methods for the reconstruction of bone defects or for augmentative procedures can be applied in the future or are already being applied in the field of oral and maxillofacial surgery.

Manganese Oxide Nanozyme-Doped Diatom for Safe and Efficient Treatment of Peri-Implantitis

Peri-implantitis is a major cause of dental implant failure. Bacterial biofilm contamination on the implant induces surrounding bone resorption and soft tissue inflammation, leading to severe deterioration of oral health. However, conventional biofilm removal procedures, such as mechanical decontamination and antiseptic application, are not effective enough to induce reosseointegration on decontaminated implant surfaces. This is due to (1) incomplete decontamination of the biofilm from inaccessible areas and (2) physicochemical alteration of implant surfaces caused by decontamination procedures. Herein, a safe and effective therapeutic approach for peri-implantitis is developed, which involves decontamination of implant-bound biofilms using the kinetic energy of microsized oxygen bubbles generated from the catalytic reaction between hydrogen peroxide (H₂O₂) and manganese oxide (MnO₂) nanozyme sheet-doped silica diatom microparticles (Diatom Microbubbler, DM). Rapidly moving microsized DM particles are able to penetrate narrow spaces between implant screws, exerting just the right amount of force to entirely destroy biofilms without harming the surrounding mucosa or implant surfaces, as opposed to conventional antiseptics such as chlorhexidine or 3% H₂O₂ when used alone. Consequently, decontamination with DM facilitates successful reosseointegration on the peri-implantitis-affected implant surface. In summary, our new DM-based therapeutic approach will become a promising alternative to resolve clinically challenging aspects of peri-implantitis.

The Use of the Diode Laser against the Microbiome on Composites Closing the Screw Access Hall (Sah) in the Reconstruction of Dental Implants: Ex Vivo Studies

Patients undergoing implant treatment are at risk of peri-implant bone loss, which is most often caused by the adverse effects of microorganisms, but there are few proven procedures for their reduction. The aim of the research was to identify the microorganisms inhabiting the composites used to close the screw access hole (SAH), compare them numerically with those present on the surface of crowns and teeth, and optimize the doses of the diode laser, which will reduce microorganisms and will not deteriorate the roughness of polished composites. Patients were swabbed from the surface of SAH composites, from porcelain and zirconium restorations, and from teeth, and then the number of microorganisms was determined by using a culture technique. Microorganisms were identified by MALDI–TOF MS and NGS sequencing. The effectiveness of diode laser irradiation was achieved by using four variants of exposure. After polishing and laser irradiation, the surface roughness of the composites was studied by using optical profilometry. On the surface of SAH, 10⁶ to 10⁸ microorganisms were identified at 0.4 cm², including many pathogenic species. Among the materials used for the reconstruction of dental implants, the greatest microbiological contamination was found on the composites used to close the SAH. The diode laser with a wavelength of 810 nm with an average power of 3.84 W, during 60 s and 2 × 30 s, has a biocidal effect and does not significantly change the surface roughness of composites. The best reduction of microorganisms was achieved on a composite polished with a polishing rubber and then with a Sof-Lex™ Pre-Polishing Spiral beige (3M ESPE, Ave. St. Paul., MN, USA). Studies have shown that using the optimal laser dose can help treat periimplantitis. These studies provide important information on the possibility of the effective elimination of microorganisms by using a diode laser in the treatment of peri-implant bone loss.

Light-Propelled Nanorobots for Facial Titanium Implants Biofilms Removal

Titanium miniplates are biocompatible materials used in modern oral and maxillofacial surgery to treat facial bone fractures. However, plate removal is often required due to implant complications. Among them, a biofilm formation on an infected miniplate is associated with severe inflammation, which frequently results in implant failure. In light of this, new strategies to control or treat oral bacterial biofilm are of high interest. Herein, the authors exploit the ability of nanorobots against multispecies bacterial biofilm grown onto facial commercial titanium miniplate implants to simulate pathogenic conditions of the oral microenvironment. The strategy is based on the use of light-driven self-propelled tubular black-TiO₂ /Ag nanorobots, that unlike traditional ones, exhibit an extended absorption and motion actuation from UV to the visible-light range. The motion analysis is performed separately over UV, blue, and green light irradiation and shows different motion behaviors, including a fast rotational motion that decreases with increasing wavelengths. The biomass reduction is monitored by evaluating LIVE/DEAD fluorescent and digital microscope images of bacterial biofilm treated with the nanorobots under motion/no-motion conditions. The current study and the obtained results can bring significant improvements for effective therapy of infected metallic miniplates by biofilm.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Hydroxyapatite Pellets as Versatile Model Surfaces for Systematic Adhesion Studies on Enamel: A Force Spectroscopy Case Study

Research into materials for medical application draws inspiration from naturally occurring or synthesized surfaces, just like many other research directions. For medical application of materials, particular attention has to be paid to biocompatibility, osseointegration, and bacterial adhesion behavior. To understand their properties and behavior, experimental studies with natural materials such as teeth are strongly required. The results, however, may be highly case-dependent because natural surfaces have the disadvantage of being subject to wide variations, for instance in their chemical composition, structure, morphology, roughness, and porosity. A synthetic surface which mimics enamel in its performance with respect to bacterial adhesion and biocompatibility would, therefore, facilitate systematic studies much better. In this study, we discuss the possibility of using hydroxyapatite (HAp) pellets to simulate the surfaces of teeth and show the possibility and limitations of using a model surface. We performed single-cell force spectroscopy with single Staphylococcus aureus cells to measure adhesion-related parameters such as adhesion force and rupture length of cell wall proteins binding to HAp and enamel. We also examine the influence of blood plasma and saliva on the adhesion properties of S. aureus. The results of these measurements are matched to water wettability, elemental composition of the samples, and the change in the macromolecules adsorbed over time on the surface. We found that the adhesion properties of S. aureus were similar on HAp and enamel samples under all conditions: Significant decreases in adhesion strength were found equally in the presence of saliva or blood plasma on both surfaces. We therefore conclude that HAp pellets are a good alternative for natural dental material. This is especially true when slight variations in the physicochemical properties of the natural materials may affect the experimental series.

Succession of oral bacterial colonizers on dental implant materials: An in vitro biofilm model

OBJECTIVES

Oral bacterial adhesion on dental implant materials has been extensively studied using in vitro systems but has yielded results restricted to in vitro growth patterns due to limitations in species selection, sustained fastidious anaerobe growth, and mixed culture longevity. The aim of this study was to develop an oral bacterial biofilm model consisting of colonizers representative of the oral microbiome exhibiting temporal shifts characteristic of plaque development and maturation in vivo.

METHODS

Streptococcus oralis, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis were grown in monoculture prior to combination in mixed culture. Commercially pure titanium (cpTi) and yttria-stabilized zirconia (ZrO₂) disks with polished, acid-etched, or sandblasted surfaces were prepared to evaluate oral bacterial adhesion. After 6 h, 1, 3, 7, 14 and 21 days, genomic DNA from planktonic and adherent bacteria was isolated. Quantitative polymerase chain reaction (qPCR) was used to enumerate the amount and proportion of each species.

RESULTS

Early-colonizing S. oralis and A. actinomycetemcomitans, dominated after 6 h prior to secondary colonization by F. nucleatum and V. parvula in planktonic (1 day) and sessile (3 days) form. A. naeslundii maintained relatively low but stable bacterial counts throughout testing. After 14 days, late-colonizing P. gingivalis became established in mixed culture and persisted, becoming the dominant species after 21 days. The composition of adherent bacteria across all substrates was statistically similar at all timepoints with notable exceptions including lower S. oralis bacterial counts on polished cpTi (3 days).

SIGNIFICANCE

Within the present model's limitations, multispecies oral bacterial attachment is similar on surface-treated cpTi and ZrO₂.

Cytotoxicity of Dental Cements on Soft Tissue Associated with Dental Implants

Purpose

To investigate and compare the cellular host response of human gingival fibroblasts (HGF) on four currently used cements. Methods and Material. 5 cement pellet samples were made for each of the 4 test cements (n = 20). The cements used for this study were zinc phosphate, zinc oxide noneugenol (ZOE), RelyX U200, and glass ionomer cement (GIC). One commercially available cell line was used to investigate the cytotoxicity of peri-implant tissues. Direct contact cell culture testing was conducted following International Organization for Standardization (ISO) methods 10993-5 and 10993-12 (MTT assay test). Cell cultures without dental cement were considered as control. Cells were allowed to grow and confluence over 48 hours after subcultivation according to standard laboratory procedures. The cells were kept in direct contact with the cement samples for 24 hours before being subjected to analysis. All specimens were tested in triplicate to validate the results. Quantitative evaluation of cytotoxicity was done to measure cell death and inhibition of cell growth. Results were analyzed using 1-way ANOVA (a = 0.05) followed by Tukey B post hoc test.

Results

The results of the study showed that HGF was vulnerable to the dental cement test material. GIC, zinc phosphate, ZOE, and resin cement were cytotoxic in decreasing order, respectively, and significantly reduced the cell viability after exposure to HGF (p < 0.001).

Conclusions

Within the limitations of this in vitro cellular study, results indicated that the test dental cements were cytotoxic to HGF. The highest cytotoxicity was observed in GIC followed by zinc phosphate, ZOE, and resin cement.

Antimicrobial effects of a new brushing solution concept on a multispecies in vitro biofilm model growing on titanium surfaces

OBJECTIVES

To evaluate the antibiofilm and antibacterial effects of a new brushing solution concept, in a validated peri-implant biofilm model.

MATERIALS AND METHODS

A multispecies in vitro biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum, was used. To evaluate the antibiofilm capacity, titanium discs (Ti-SLA) were immersed in 1 ml of the tested solution (one tablet dissolved in warm water) for 2 min, prior and every 24 h during a 3-day biofilm development. Negative (water) and positive (0.12% chlorhexidine/0.05% cetylpyridinium chloride mouth rinse) controls treated discs were run in parallel. To evaluate the antibacterial effects, planktonic cells and 72-h biofilms on sterile Ti-SLA discs were exposed (2 min) to the mentioned treatments. Biofilm structure was analysed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Bacterial load was measured by quantitative polymerase chain reaction and by culture in planktonic cells.

RESULTS

The tested product showed antibiofilm effects, impacting on the 48-h and 72-h biofilm thickness and significantly reducing viability of all bacterial species, except A. actinomycetemcomitans. Antibacterial effects were observed against the six bacterial species in planktonic state and in 72-h biofilms, especially for F. nucleatum and A. actinomycetemcomitans.

CONCLUSION

The tested brushing solution demonstrated antibacterial and antibiofilm properties, mainly against the peri-implant pathogens included in the validated in vitro biofilm model used.

The Use of a Diode Laser for Removal of Microorganisms from the Surfaces of Zirconia and Porcelain Applied to Superstructure Dental Implants

The aim of this paper was to study the effectiveness of a diode laser (LD) for removal of microorganisms isolated from porcelain and zirconia crown surfaces used in implantoprosthetics in order to minimize infections around dental implants. In order to optimize biocidal efficacy of the process (at the same time, avoiding increasing the surface roughness during decontamination) the effects of diode laser doses were investigated. The irradiation was performed with a diode laser at the wavelength of λ = 810 nm in three variants with a different number of repetitions (1 × 15 s, 2 × 15 s, 3 × 15 s). The quantitative microbial contamination of the surface of teeth, porcelain and zirconia crowns assessment was made using the culture-dependent method. The identification of microorganisms took place using the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and next-generation sequencing (NGS) methods. The studies of the surface morphology and roughness were carried out by means of the optical profilometry, scanning electron microscopy (SEM) and optical microscopy with the C1 confocal attachment. The most important conclusion from the research is the fact that the laser operation, regardless of the exposure time, effectively eliminates the microorganisms from the surfaces used for dental implant rebuilding and does not have a destructive effect on the tested material.

Surface Characterization and Assessment of Biofilm Formation on Two Titanium-Based Implant Coating Materials

Implant-related oral diseases such as peri-implantitis and peri-mucositis are largely initiated by bacterial colonization on artificial implant surfaces. Therefore, implant and abutment material characteristics that minimize bacterial attachment and subsequent biofilm formation are important factors in reducing the risk of infection-related implant failure. This study compares the properties of two different titanium-based implant coating materials, titanium nitride (TiN) and titanium carbon nitride (TiCN). Surface hydrophilicity/ hydrophobicity and roughness were evaluated via contact angle measurements and surface profiling with white light interferometry, respectively. TiN-coated surfaces were hydrophobic according to its contact angle higher than 72.7°, whereas TiCN-coated surfaces were hydrophilic with its contact angle of 53.6°. The average roughness (Ra) was greater for TiCN than TiN with the root mean square roughness (Rq) being significantly higher. These findings are in contrast to the common understanding for titanium-based materials that surface roughness and hydrophobicity are positively correlated. A well-established saliva-based oral microbial biofilm model was employed to compare bacterial attachment and biofilm formation on TiN and TiCN. Growth conditions included relevant host components such as blood as well as the presence or absence of dietary carbohydrates. The accumulated biomass was measured by crystal violet staining and the bacterial community profiles of the attached biofilms were determined via 16S rRNA gene microbiome sequencing at different time points over a 7-day period. At all time points, TiCN showed significantly less bacterial attachment and biofilm formation compared to TiN. This implied the importance of the hydrophilic state over surface roughness as parameter for the prevention of oral microbial attachment. Although, the biofilm community composition was very similar on both materials, environmental growth conditions resulted in significantly different bacterial profiles independent of the surface. In conclusion, TiCN coating produced a unique titanium surface which is rougher but more hydrophilic. TiCN-coated surfaces exhibited reduced bacterial attachment and biofilm formation in comparison to TiN coating. This coating technique can be further explored to improve implant and abutment success.

Use of wide-field optical fluorescence for visualization of oral biofilm in a patient with peri-implant mucositis: a new approach

Peri-implant diseases, caused by bacteria from biofilm related to dental implants, are one of the main causes of late loss of implants. In this sense, peri-implant diseases are divided into peri-implant mucositis, when it affects only the soft tissues, and peri-implantitis, when there is a bone involvement, which can lead to the failure of dental implant therapy. Thus, biofilm removal is essential for peri-implant health, allowing long-term success in implant therapy. To improve the visualization of oral biofilm, which is usually transparent or colorless, disclosing agents have been routinely used. However, disclosing agents have allergenic potential and can cause staining extrinsically in restorative and prosthetic materials, leading to aesthetic impairment. Thus, the use of fluorescence has been studied as an alternative for visualization of oral biofilm. Therefore, this report describes the use of wide-field optical fluorescence for visualization of oral biofilm associated with implants and teeth, in a routine appointment and follow-up of a partially edentulous patient with peri-implant mucositis. In addition, this report showed wide-field optical fluorescence can be used in a clinical routine of care of patients with dental implants. In this sense, wide-field optical fluorescence allowed easy and immediate visualization of the mature oral biofilm for its adequate removal, evaluation of the quality of restoration to sealing of screw access-hole of implant and identification of cariogenic lesions, without risk of allergic reactions or staining of prostheses and restorations.

Properties of silver contained coatings on CoCr alloys prepared by vacuum plasma spraying

The silver contained coatings on cast Cobalt Chrome (CoCr) alloys were prepared by vacuum plasma spraying technique. The Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), energy dispersive spectrometry (EDS), properties of corrosion resistance, wear resistance and effect of vitro antibacterial on the surface of silver contained coating were investigated. The cytotoxicity of the coatings was performed with L-929 fibroblasts by MTT assay. SEM showed that the surfaces of the coatings were dense, smooth, no obvious cracks except only a few pores. XRD analysis indicated that the contents of the surface were mainly Ag and Cr except a small amount of Ag₂O, Cr₂O₃. EDS analysis indicated that the distributions of Cr and Ag were uniform without any large-scale clustering. The wear resistance of silver coatings is similar to that of CoCr alloys, and the corrosion resistance is slightly better than that of CoCr alloys. The Ag coating had no significant effect on the proliferation of L929 cells. The antibacterial results indicated that the number of S. mutans and C. albicans were significantly reduced on the surface of silver contained coating than that of CoCr alloys. All the results indicated that the silver contained coatings can be achieved by vacuum plasma spraying technique with good surface characteristic and antibacterial properties and have promising applications in biomedical area.

In vitro biofilm formation on different ceramic biomaterial surfaces: Coating with two bactericidal glasses

OBJECTIVES

To compare biofilm formation on the surface of different ceramic biomaterials to be used in implant dentistry.

METHODS

In vitro biofilm formation was investigated from mixtures of standard reference strains of Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Sterile ceramic calcium hydroxyapatite discs (HA) as control, sterile Al₂O₃/Ce-TZP nanocomposite sandblasted discs (material A1) and sterile Al₂O₃/Ce-TZP nanocomposite sandblasted discs and coated with two types of antimicrobial glasses (materials A2 and A3) were used. Biofilms were grown on the four surfaces and evaluated after 12, 24, 48 and 72 h of incubation. Biofilms were examined by confocal laser scanning microscopy (CLSM). In addition, counts of live bacterial cells of the target species A. actinomycetemcomitans, F. nucleatum and P. gingivalis were calculated by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA). For data analysis, bacterial counts were compared with a multivariate general lineal model.

RESULTS

Using CLSM, cell vitality decreased in A2 and A3. With qPCR-PMA, significant differences in vitality were observed forA. actinomycetemcomitans in A3 after 48 and 72 h of incubation. With respect to the development of the biofilms, a significant increase in counts on HA and materials A1 and A2 was observed for A. actinomycetemcomitans and F. nucleatum. Conversely, for P. gingivalis, no differences were found for HA and materials A1 and A2.

SIGNIFICANCE

Differences in biofilm formation were detected among the different tested materials. The ceramic material A3 has an effect on the vitality of A. actinomycetemcomitans growing in an in vitro biofilm model.

Multifunctional Coatings and Nanotopographies: Toward Cell Instructive and Antibacterial Implants

In biomaterials science, it is nowadays well accepted that improving the biointegration of dental and orthopedic implants with surrounding tissues is a major goal. However, implant surfaces that support osteointegration may also favor colonization of bacterial cells. Infection of biomaterials and subsequent biofilm formation can have devastating effects and reduce patient quality of life, representing an emerging concern in healthcare. Conversely, efforts toward inhibiting bacterial colonization may impair biomaterial-tissue integration. Therefore, to improve the long-term success of medical implants, biomaterial surfaces should ideally discourage the attachment of bacteria without affecting eukaryotic cell functions. However, most current strategies seldom investigate a combined goal. This work reviews recent strategies of surface modification to simultaneously address implant biointegration while mitigating bacterial infections. To this end, two emerging solutions are considered, multifunctional chemical coatings and nanotopographical features.

Effect of Cu on microstructure, mechanical properties, corrosion resistance and cytotoxicity of CoCrW alloy fabricated by selective laser melting

In the study, CoCrWCu alloys with differing Cu content (2, 3, 4 wt%) were prepared by selective laser melting using mixture powders consisting of CoCrW and Cu, aiming at investigating the effect of Cu on the microstructures, mechanical properties, corrosion behavior and cytotoxicity. The SEM observations indicated that the Cu content up to 3 wt% caused the Si-rich precipitates to segregate along grain boundaries and in the grains, and EBSD analysis suggested that the Cu addition decreased the recrystallization degree and increased the grain diameter and fraction of big grains. The tensile tests found that the increasing Cu content led to a decrease of mechanical properties compared with Cu-free CoCrW alloy. The electrochemical tests revealed that the addition of Cu shifted the corrosion potential toward nobler positive, but increased the corrosion current density. Also, a more protective passive film was formed when 2 wt% Cu content was added, but the higher Cu content up to 3 wt% was detrimental to the corrosion resistance. It was noted that there was no cytotoxicity for Cu-bearing CoCrW alloys to MG-63 cell and the cells could spread well on the surfaces of studied alloys. Meanwhile, the Cu-bearing CoCrW alloy exhibited an excellent antibacterial performance against E.coli when Cu content was up to 3 wt%. It is suggested that the feasible fabrication of Cu-bearing CoCrW alloy by SLM using mixed CoCrW and Cu powders is a promising candidate for use in antibacterial oral repair products. This current study also can aid in the further design of antibacterial Cu-containing CoCrW alloying powders.

Effects of d-valine on periodontal or peri-implant pathogens: Porphyromonas gingivalis biofilm

BACKGROUND

When presented with a surface or an interface, bacteria often grow as biofilms in which cells are held together by an extracellular matrix. Biofilm formation on implants is an initiating factor for their failure. Porphyromonas gingivalis is the primary etiologic bacteria of initiation and progression of periodontal disease. This microorganism is also the risk factor of many systemic diseases, such as cardiovascular disease, diabetes, and pulmonary infection. To date, no medication that can remove such biofilm has been accepted for clinical use. D-valine (D-val) can reportedly inhibit the formation of biofilm and/or trigger the scattering of mature biofilm. Accordingly, this study investigated the effects of d-val on single-species P. gingivalis biofilms in vitro.

METHODS

P. gingivalis grown in brain heart infusion culture with or without d-val was inoculated in 24- or 96-well plates. After incubation for 72 hours, biomass via crystal violet staining, extracellular polysaccharide production by biofilms, and scanning electron microscopy (SEM) were used to determine the d-val concentration that can effectively prevent P. gingivalis biofilm formation.

RESULTS

Experimental results showed that d-val effectively inhibited biofilm formation at concentrations ≥50 mM (mMol/L), and that d-val inhibition increased with increased concentration. Moreover, at high concentrations, the bacterial form changed from the normal baseball form into a rodlike shape. d-val also notably affected extracellular polysaccharide production by P. gingivalis.

CONCLUSIONS

d-val can inhibit P. gingivalis biofilm formation, and high concentrations can affect bacterial morphology.

Anti-Bacteria and Microecosystem-Regulating Effects of Dental Implant Coated with Dimethylaminododecyl Methacrylate

The effects of dimethylaminododecyl methacrylate (DMADDM) modified titanium implants on bacterial activity and microbial ecosystem of saliva-derived biofilm were investigated for the first time. Titanium discs were coated with DMADDM solutions at mass fractions of 0 mg/mL (control), 1, 5 and 10 mg/mL, respectively. Biomass accumulation and metabolic activity of biofilms were tested using crystal violet assay and MTT (3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. 16S rRNA gene sequencing was performed to measure the microbial community. Live/dead staining and scanning electron microscopy (SEM) were used to value the structure of biofilm. The results showed that the higher mass fraction of DMADDM the coating solution had, the significantly lower the values of metabolic activity and accumulated biofilms got, as well as fewer live cells and less extracellular matrix. Moreover, 5 mg/mL of DMADDM was the most effective concentration, as well as 10 mg/mL. In microecosystem-regulation, the DMADDM modified titanium implant decreased the relative abundance of Neisseria and Actinomyces and increased the relative abundance of Lactobacillus, a probiotic for peri-implant diseases. In conclusion, via inhibiting growth and regulating microecosystem of biofilm, this novel titanium implant coating with DMADDM was promising in preventing peri-implant disease in an ‘ecological manner’.

Inhibition of malodorous gas formation by oral bacteria with cetylpyridinium and zinc chloride

OBJECTIVE

The antimicrobial efficacy of zinc- (ZnCl₂) and cetylpyridinium-chloride (CPC) and their inhibition capacity on volatile sulfur compound (VSC) production by oral bacterial strains were investigated.

DESIGN

Minimum inhibitory concentrations (MIC) and growth curves were determined for ZnCl₂, CPC, and CPC with ZnCl₂ solutions against eight oral microorganisms (Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, Tannerella forsythia, Staphylococcus aureus and Streptococcus mutans) known to be involved in the pathophysiology of both halitosis and periodontal disease. Gas chromatography was applied to measure VSCs (H₂S, CH₃SH, (CH₃)₂S) production levels of each strains following exposure to the solutions.

RESULTS

ZnCl₂ and CPC effectively inhibited growth of all eight strains. ZnCl₂ was generally more effective than CPC in suppressing bacterial growth excluding A. actinomycetemcomitans, P. intermedia, and T. forsythia. Synergism between CPC and ZnCl₂ was shown in A. actinomycetemcomitans. The MIC for CPC was significantly lower than ZnCl₂. VSC production was detected in five bacterial strains (A. actinomycetemcomitans, F. nucleatum, P. gingivalis, T. denticola, and T. forsythia). Each bacterial strain showed unique VSCs production profiles. H₂S was produced by F. nucleatum, P. gingivalis, and T. denticola, CH₃SH by all five strains and (CH₃)₂S by A. actinomycetemcomitans, F. nucleatum, P. gingivalis, and T. denticola. Production of CH₃SH, the most malodorous component among the three major VSCs from mouth air was evident in F. nucleatum and T. forsythia.

CONCLUSION

Both ZnCl₂ and CPC effectively inhibit bacterial growth causative of halitosis and periodontal disease, resulting in a direct decrease of bacterial VSCs production.

Regenerating Bone via Multifunctional Coatings: The Blending of Cell Integration and Bacterial Inhibition Properties on the Surface of Biomaterials

In dentistry and orthopedics, it is well accepted that implant fixation is a major goal. However, an emerging concern is bacterial infection. Infection of metallic implants can be catastrophic and significantly reduce patient quality of life. Accordingly, in this work, we focus on multifunctional coatings to simultaneously address and mitigate both these problems. We have developed a tailor-made peptide-based chemical platform that integrates the well-known RGD cell adhesive sequence and the lactoferrin-derived LF1-11 antimicrobial peptide. The platform was covalently grafted on titanium via silanization and the functionalization process characterized by contact angle, XPS, and QCM-D. The presence of the platform statistically improved the adhesion, proliferation and mineralization of osteoblast-like cells compared to control surfaces. At the same time, colonization by representative bacterial strains was significantly reduced on the surfaces. Furthermore, the biological potency of the multifunctional platform was verified in a co-culture in vitro model. Our findings demonstrate that this multifunctional approach can be useful to functionalize biomaterials to both improve cell integration and reduce the risk of bacterial infection.

Is it safe to reuse dental implant healing abutments sterilized and serviced by dealers of dental implant manufacturers? An in vitro sterility analysis

PURPOSE

This study was undertaken to investigate the sterility of used healing abutments sterilized and serviced by dealers of dental implant manufacturers.

MATERIALS AND METHODS

Sixty used but sterilized healing abutments in sealed sterilization pouches were obtained from 6 manufacturers unaware of the study design and equally grouped from A to F. The sterilization pouches were examined for perforation. The driver slots and screw grooves of healing abutments were examined for calculus and scratches under a ×5 LED magnifying lamp, without opening the pouches. Each abutment was immersed in brain heart infusion broth in test tubes and incubated.

RESULTS

Macroscopic observation of 57 healing abutments revealed dirty screw grooves (10.5%) and partially filled driver slots (5.2%). None of the group C, E, and F samples showed turbidity. Penicillium variabile was morphologically identified in 3 abutments of group A. Enterococcus faecalis and E faecium were detected in 1 abutment each of groups B and D, respectively.

CONCLUSION

Reuse of healing abutments can be cost effective in dental practice. However, used abutments sterilized and serviced by dental implant dealers might be a source of cross-infection. They should therefore be cleaned and resterilized before reuse as a precaution.

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

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.

Investigation of the in vitro photocatalytic antibacterial activity of nanocrystalline TiO2 and coupled TiO2/Ag containing copolymer on the surface of medical grade titanium

Antibacterial surfaces have been in the focus of research for years, driven by an unmet clinical need to manage an increasing incidence of implant-associated infections. The use of silver has become a topic of interest because of its proven broad-spectrum antibacterial activity and track record as a coating agent of soft tissue implants and catheters. However, for the time being, the translation of these technological achievements for the improvement of the antibacterial property of hard tissue titanium (Ti) implants remains unsolved. In our study, we focused on the investigation of the photocatalysis mediated antibacterial activity of silver (Ag), and Ti nanoparticles instead of their pharmacological effects. We found that the photosensitisation of commercially pure titanium discs by coating them with an acrylate-based copolymer that embeds coupled Ag/Ti nanoparticles can initiate the photocatalytic decomposition of adsorbed S. salivarius after the irradiation with an ordinary visible light source. The clinical isolate of S. salivarius was characterised with MALDI-TOF mass spectrometer, while the multiplication of the bacteria on the surface of the discs was followed-up by MTT assay. Concerning practical relevance, the infected implant surfaces can be made accessible and irradiated by dental curing units with LED and plasma arc light sources, our research suggests that photocatalytic copolymer coating films may offer a promising solution for the improvement of the antibacterial properties of dental implants.

An in vitro study on disinfection of titanium surfaces

OBJECTIVE

The aim of this in vitro study was to evaluate the efficacy of different methods used for the decontamination of titanium surfaces previously infected with a Staphylococcus aureus biofilm.

MATERIALS AND METHODS

S. aureus biofilms were grown on three different titanium surfaces (n = 114); polished, sandblasted large-grit acid-etched (SLA) and SLActive. The experimental groups were divided into six different disinfection modalities as follows: (i) rinsing with phosphate-buffered saline, (ii) rinsing with chlorhexidine digluconate 0.2% (CHX), (iii) application of photodynamic therapy (PDT), (iv) use of cotton pellet, (v) use of titanium brush (TiB) and (vi) the use of TiB and PDT. The decontamination effect of each modality was evaluated by microbial culture analysis and by scanning electron microscopy imaging. Two-way analysis of variance (ANOVA) and Bonferroni's post hoc comparisons were used to compare mean differences between colony-forming units per millilitre (CFU/ml) values, surfaces and treatments (P < 0.025).

RESULTS

This study demonstrated that the combination protocol (TiB and PDT) was the most effective in reducing S. aureus (P < 0.025) on polished (2.0 × 10³  CFU/Disc) and SLA surface (6.9 × 10³  CFU/Disc). On the SLActive surface, the combination treatment was not significantly different to the TiB group (1.0 × 10⁵ CFU/Disc) or the PDT group (2.0 × 10⁵ CFU/Disc).

CONCLUSION

The combined technique of TiB and PDT was shown to be an efficient method in reducing the number of S. aureus in both polished and rough titanium surfaces. These findings prompt further investigations in titanium decontamination techniques with a combination of TiB and PDT within a natural microcosm bacterial environment.

Influence of biomaterial nanotopography on the adhesive and elastic properties of Staphylococcus aureus cells

Despite the well-known beneficial effects of biomaterial nanopatterning on host tissue integration, the influence of controlled nanoscale topography on bacterial colonisation and infection remains unknown.

Installing multifunctionality on titanium with RGD-decorated polyurethane-polyurea roxithromycin loaded nanoparticles: toward new osseointegrative therapies

A novel class of polyurethane-polyurea nanoparticles (PUUa NPs) to install multifunctionality on biomaterials is presented. Biofunctionalization of titanium with roxithromycin loaded RGD-decorated PUUa NPs results in an outstanding improvement of osteoblast adhesion and strong suppression of bacterial attachment. This strategy represents a powerful approach to enhance the osseointegration of implant materials.

Effect of UV-photofunctionalization on oral bacterial attachment and biofilm formation to titanium implant material

Bacterial biofilm infections remain prevalent reasons for implant failure. Dental implant placement occurs in the oral environment, which harbors a plethora of biofilm-forming bacteria. Due to its trans-mucosal placement, part of the implant structure is exposed to oral cavity and there is no effective measure to prevent bacterial attachment to implant materials. Here, we demonstrated that UV treatment of titanium immediately prior to use (photofunctionalization) affects the ability of human polymicrobial oral biofilm communities to colonize in the presence of salivary and blood components. UV-treatment of machined titanium transformed the surface from hydrophobic to superhydrophilic. UV-treated surfaces exhibited a significant reduction in bacterial attachment as well as subsequent biofilm formation compared to untreated ones, even though overall bacterial viability was not affected. The function of reducing bacterial colonization was maintained on UV-treated titanium that had been stored in a liquid environment before use. Denaturing gradient gel-electrophoresis (DGGE) and DNA sequencing analyses revealed that while bacterial community profiles appeared different between UV-treated and untreated titanium in the initial attachment phase, this difference vanished as biofilm formation progressed. Our findings confirm that UV-photofunctionalization of titanium has a strong potential to improve outcome of implant placement by creating and maintaining antimicrobial surfaces.

Nanoadhesion of Staphylococcus aureus onto Titanium Implant Surfaces

Adhesion of bacteria to dental implant surfaces is the critical initial step in the process of biofilm colonization; however, the specific nanoadhesive interactions occurring during the first contact between bacterial cells and biomaterial substrates remain poorly understood. In this report, we utilize single-cell force spectroscopy to characterize the dynamics of the initial interaction between living Staphylococcus aureus cells and machined titanium surfaces at the nanoscale. Values for maximum adhesion force were found to increase from 0-s (-0.27 ± 0.30 nN) to 60-s (-9.15 ± 0.78 nN) surface delays, with similar results observed for total adhesion work (7.39 ± 2.38 and 988.06 ± 117.08 aJ, respectively). Single unbinding events observed at higher surface delays were modeled according to the wormlike chain model, obtaining molecular contour-length predictions of 314.06 ± 9.27 nm. Average single-bond rupture forces of -0.95 ± 0.04 nN were observed at increased contact times. Short- and long-range force components of bacterial adhesion were obtained by Poisson analysis of single unbinding event peaks, yielding values of -0.75 ± 0.04 and -0.58 ± 0.15 nN, respectively. Addition of 2-mg/mL chlorhexidine to the buffer solution resulted in the inhibition of specific adhesive events but an increased overall adhesion force and work. These results suggest that initial attachment of S. aureus to smooth titanium is mostly mediated by short-range attractive forces observed at higher surface delays.

Antibiotic prophylaxis for preventing infectious complications in orthognathic surgery

BACKGROUND

Orthognathic surgery (OS) is a term that refers to many elective surgical techniques to correct facial deformity; the associated malocclusion and functional disorders related to the stomatognathic system. Whilst such surgery is classed as "clean-contaminated", the usefulness of and the most appropriate regimen for antibiotic prophylaxis in these patients are still debated.

OBJECTIVES

To assess the effects of antibiotic prophylaxis for preventing surgical site infection (SSI) in people undergoing orthognathic surgery.

SEARCH METHODS

In June 2014, we searched the Cochrane Wounds Group Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. We also searched Google Scholar and performed manual searches in journals relevant to the topic, conference proceedings and lists of references of potentially included articles. We did not restrict the search and study selection with respect to language, date of publication or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving people undergoing orthognathic surgery comparing one regimen of antibiotic prophylaxis with any other regimen or placebo. The primary outcome was SSI, and secondary outcomes were systemic infections, adverse events, duration of hospital stay and health-related quality of life. Two review authors screened articles independently.

DATA COLLECTION AND ANALYSIS

Data were abstracted independently by two review authors, and agreement was checked. Risk of bias was assessed using the Cochrane risk of bias tool. Antibiotic regimens were classified as preoperative (one dose before surgery), short-term (before or during surgery and/or during the same day of surgery) and long-term (before or during surgery and longer than one day after surgery) antibiotic prophylaxis. Random-effects meta-analyses using inverse variance methods were undertaken when possible. We report risk ratios (RRs) and their corresponding 95% confidence intervals (CIs).

MAIN RESULTS

A total of 11 trials were included in this review. Most of the studies had an unclear risk of bias prompting us to downgrade the quality of evidence for our outcomes. Seven of these trials provided evidence for the main comparison and the primary outcome and these were pooled. Overall, long-term antibiotic prophylaxis probably reduces the risk of SSI (plausible effects range between a 76% to a 0.26% relative reduction in SSI with long-term antibiotic prophylaxis) (472 participants; RR 0.42, 95% CI 0.24 to 0.74; moderate-quality evidence). There is uncertainty surrounding the relative effects of short-term antibiotics compared with a single dose (220 participants; RR 0.34, 95% CI 0.09 to 1.22; low-quality evidence). No reports described adverse effects associated with the drugs in those trials that reported in this outcome. None of these trials assessed or reported data regarding other outcomes, and information was insufficient to show whether a specific antibiotic is better than another.

AUTHORS' CONCLUSIONS

For people undergoing orthognathic surgery, long term antibiotic prophylaxis decreases the risk of SSI compared with short-term antibiotic prophylaxis and the is uncertainty of whether short-term antibiotic prophylaxis decreases SSi risk relative to a single pre-operative dose of prophylactic antibiotics.