Different Impact of Suspended Al2O3 Nanoparticles on Microbial Communities: Formation of 2D-Networks (Without Humic Acids) or 3D-Colonies (With Humic Acids).

The use of metal-based and, particularly, Al2O3 nanoparticles (Al2O3-NP) for diverse purposes is exponentially growing. However, the growth of such promissory market is not accompanied by a parallel extensive investigation related to the impact of this pollution on groundwater and biological systems. Pseudomonas species, ubiquitous, environmentally critical microbes, frequently respond to stress conditions with diverse strategies that generally include extracellular polymeric substances (EPS) formation. The aim of this study is to report that changes in the aqueous environment, particularly, the addition of Al2O3-NP without and with humic acids, induce different adaptive strategies of Pseudomonas aeruginosa early biofilms. To this purpose, early biofilms were incubated in diluted culture media without (control) and with Al2O3-NP, and with humic acids (HA-control, HA-Al2O3-NP) for 24 h. 3D colonies with EPS strings and isolated bacteria in their surroundings were detected in the control biofilms. Unlikely, an unusual adaptive behaviour was developed in the presence of Al2O3-NP. Bacteria opt to disassemble the 3D arrangements and to implement a 2D network promoting morphological and size changes of bacterial cells (small coccoid shapes). Remarkably, this strategy allows their temporarily non-EPS-depending survival without decreasing the number of cells. This behaviour was not observed with ZnO-NP, HA-Al2O3-NP, or HA-ZnO-NP. Physicochemical analysis revealed that HA were adsorbed on Al2O3-NP and promoted the Al(III) ions complexation. This supports the hypothesis that the reduction of toxicity of Al ions and the 3D colony formation in the presence of HA-Al2O3-NP is promoted by the complexation of the metal ions with HA components.

Complications and treatment errors in root coverage procedures.

Root coverage procedures have become very common in clinical dental practice. Even though these techniques are considered safe, the clinician may face several issues during the therapy due to their surgical nature. Some of these issues can be defined strictly as complications inherent to the procedure, whereas others are medical errors or treatment errors. This review will focus on describing treatment errors and complications that may arise during different phases of the root coverage therapeutic process and on how to prevent and manage them.

Patient-reported outcome measures after periodontal surgery.

OBJECTIVES: The present study aimed to explore the impact of different periodontal surgical treatments on the quality of life and postoperative morbidity. MATERIALS AND METHODS: The present study is a single-center, prospective, observational cohort trial. One hundred fifty-five patients, referred to the Periodontal Department of Bologna University who needed periodontal surgical treatment, were recruited. The self-reported perception of the postoperative course was assessed using the following anonymous questionnaires: Italian oral health impact profile (I-OHIP-14), visual analog scale (VAS) to evaluate the intensity of the pain, and 5-point Likert scale. RESULTS: Patients reported a mean OHIP-14 total score of 9.87±8.5 (range 0-42), significantly influenced by the female sex, flap extension, and periodontal dressing. A mean VAS score of 2.96±2.39 (range 0-9) was calculated, and was found to be influenced by the presence of vertical releasing incisions and palatal flap extension. Of the 155 subjects, 40 (25.8%) patients reported bleeding as a post-surgical complication, 96 (61.9%) swelling, 105 (67.7%) eating discomfort, and 44 (28.4%) reported speech discomfort. CONCLUSIONS: Within the limitations of the nature of the present study, periodontal surgical procedures have a low impact on patients' quality of life evaluated through the OHIP-14 and VAS pain questionnaires. CLINICAL RELEVANCE: Periodontal surgical procedures are safe procedures, with a limited duration of postoperative discomfort as well as the incidence of complications.

Staphylococcus aureus biofilm eradication by the synergistic effect exerted by PEG-coated silicon dots immobilized in silica films and light irradiation.

Immobilization of PEG-covered silicon dots, PEGSiDs, on glass substrates was performed following a simple strategy involving particle embedding by a sol-gel process forming a silica film on glass slides. The obtained films, denoted as fSiO x -PEGSiD, constitute a water-wettable, strongly supported, photoluminescent glass coating. The films showed high capacity for photosensitizing singlet oxygen (1O2) in the UVA when immersed in water. Staphylococcus aureus colonies formed on fSiO x -PEGSiDs modified glasses revealed the inhibition of bacterial adhesion and bacterial growth leading to the formation of loosely-packed and smaller S. aureus colonies. Upon 350 nm light irradiation of the biofilmed fSiO x -PEGSiDs -modified glasses, S. aureus growth was inhibited and bacteria killed reducing the number of living bacteria by three orders of magnitude. Eradication of attached bacteria was achieved by the synergistic effect exerted by a less adherent fSiO x -PEGSiDs surface that inhibits biofilm formation and the ability of the surface to photosensitize 1O2 to kill bacteria.

Esthetic treatment of altered passive eruption.

Altered passive eruption is described as a condition in which the relationship between teeth, alveolar bone and soft tissues creates an excessive display of gingiva, commonly known as a 'gummy smile'. While there are authors who consider altered passive eruption to be a risk to periodontal health, its impact is greatest in terms of oral esthetics. The aim of periodontal management in such cases is not only to improve patient esthetics but also to restore periodontal health by re-establishing the normal relationship between the gingival margin, alveolar bone crest and cemento-enamel junction. The aim of this article is to present a narrative review of the etiology, classification and management of altered passive eruption.

Polyethylene glycol-coated blue-emitting silicon dots with improved properties for uses in aqueous and biological environments.

Grafting of polyethylene glycol (PEG) to ultrasmall photoluminescent silicon dots (SiDs) is expected to improve and expand the applications of these particles to aqueous environments and biological systems. Herein we report a novel one-pot synthesis of robust, highly water compatible PEG-coated SiDs (denoted as PEG-SiDs) of (3.3 ± 0.5) nm size. The nanoparticles' synthesis is based on the liquid phase oxidation of magnesium silicide using PEG as reaction media and leading to high PEG density grafting. PEG-SiDs enhanced photophysical, photosensitising, and solution properties in aqueous environments are described and compared to those of 2 nm size PEG-coated SiDs with low PEG density grafting (denoted as PEG-NHSiDs) obtained from a multistep synthesis strategy. PEG-SiDs form highly dispersed suspensions in water showing stable photoluminescence and quantum yields of Φ = 0.13 ± 0.04 at 370 nm excitation in air-saturated suspensions. These particles exhibited the capacity of photosensitising the formation of singlet molecular oxygen, not observed for PEG-NHSiDs. PEG robust shielding of the silicon core luminescent properties is further demonstrated in bio-imaging experiments stressing the strong interaction between PEG-SiDs and Staphylococcus aureus smears by observing the photoluminescence of particles. PEG-SiDs were found to be nontoxic to S. aureus cells at concentrations of 100 mg ml-1, though a bacteriostatic effect on S. aureus biofilms was observed upon UV-A irradiation under conditions where light alone has no effect.

Time-Lapse Evaluation of Interactions Between Biodegradable Mg Particles and Cells.

Mg-based implants have promising applications as biodegradable materials in medicine for orthopedic, dental, and cardiovascular therapies. During wear and degradation microdebris are released. Time-lapse multidimensional microscopy (MM) is proposed here as a suitable tool to follow, in fixed intervals over 24-h periods, the interaction between cells and particles. Results of MM show interactions of macrophages (J774) with the magnesium particles (MgPa) that led to modifications of cell size and morphology, a decrease in duplication rate, and cell damage. Corrosion products were progressively formed on the surface of the particles and turbulence was generated due to hydrogen development. Changes were more significant after treating MgPa with potassium fluoride. In order to complement MM observations, membrane damage as detected by a lactase dehydrogenase (LDH) assay and mitochondrial activity as detected by a WST-1 assay with macrophages and osteoblasts (MC3T3-E1) were compared. A more significant concentration-dependent effect was detected for macrophages exposed to MgPa than for osteoblasts. Accordingly, complementary data showed that viability and cell cycle seem to be more altered in macrophages. In addition, protein profiles and expression of proteins associated with the adhesion process changed in the presence of MgPa. These studies revealed that time-lapse MM is a helpful tool for monitoring changes of biodegradable materials and the biological surrounding in real time and in situ. This information is useful in studies related to biodegradable biomaterials.

Photodynamic inactivation induced by carboxypterin: a novel non-toxic bactericidal strategy against planktonic cells and biofilms of Staphylococcus aureus.

Microbial related contamination is of major concern and can cause substantial economic losses. Photodynamic inactivation (PDI) has emerged as a suitable approach to inhibit microorganism proliferation. In this work, PDI induced by 6-carboxypterin (Cap), a biocompatible photosensitizer (PS), was analyzed. The growth inhibition of Staphylococcus aureus exposed to artificial UV-A radiation and sunlight in the presence of Cap was investigated. After UV-A irradiation, 50 µM Cap was able to decrease by three orders (with respect to the initial value) the number of S. aureus cells in early biofilms. However, this concentration was 500 times higher than that needed for eradicating planktonic cells. Importantly, under solar exposure, 100 µM Cap was able to suppress sessile bacterial growth. Thus, this strategy is able to exert a bactericidal effect on sessile bacteria and to eradicate planktonic cells by exposing the Cap-containing sample to sunlight.

Does the dimension of the graft influence patient morbidity and root coverage outcomes? A randomized controlled clinical trial.

AIM: Primary aim of this study was to evaluate if patient morbidity was improved by diminishing graft thickness and height; secondary objective was to evaluate if such graft modifications influence root coverage and aesthetic outcomes. METHODS: 60 Miller class I and II gingival recessions (GR) (≥ 3 mm in depth) were treated with the coronally advanced flap plus extraoral de-epithelialized free gingival graft (FGG). In 30 randomly selected control GRs ("big graft group"), the FGG thickness was ≥ 2 mm and the height was equal to bone dehiscence (BD); in the other 30 test defects ("small graft group"), the thickness of the FGG was <2 mm and the height was 4 mm. The post-operative patient morbidity was assessed 1 week after the surgery. The clinical and aesthetic evaluations were performed 1 year after the surgery. RESULTS: Lower analgesic assumption, better post-operative course evaluations, better patient colour match scores and better periodontist aesthetic assessments were reported in the "small graft" group. No statistically significant differences were demonstrated between the two groups in terms of recession reduction, CRC and increase in KTH. Greater GT increase was obtained in the control-treated sites. CONCLUSIONS: Coronally advanced flap plus CTG of reduced thickness and height was associated with less patient morbidity, better aesthetic evaluations with no difference in RC outcomes.

Innovative Anodic Treatment to Obtain Stable Metallic Silver Micropatches on TiO2 Nanotubes: Structural, Electrochemical, and Photochemical Properties.

Electrochemical modification of the Ti surface to obtain TiO2 nanotubes (NT-Ti) has been proposed to enhance osseointegration in medical applications. However, susceptibility to microbial adhesion, linked to biomaterial-associated infections, and the high TiO2 band gap energy, which allows light absorption almost exclusively in the ultraviolet (UV) region, limit its applications. Modifying the TiO2 semiconductor with metals such as Ag has been suggested both for antimicrobial purposes and for absorbing light in the visible region. The formation of NT-Ti with Ag micropatches (Ag-NT-Ti) is pursued with the objective of enhancing the stability of the deposits and preventing cytotoxic levels of Ag cellular uptake. The innovative process proposed here involves immersing NT-Ti in a AgNO3 solution as the initial step. Diverging from previously reported electrochemical methods, this process incorporates anodization within the TiO2 oxide formation region instead of cathodic reduction generally employed by other researchers. The final step encompasses an annealing treatment. The treatments result in the in situ Ag1+ reduction and formation of stable and active micropatches of metallic Ag on the NT-Ti surface. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman, diffuse reflectance spectroscopy (DRS), wettability assessment, and electrochemical characterizations were conducted to evaluate the modified surfaces. The well-known properties of NT-Ti surfaces were enhanced, leading to improved photocatalytic activity across both visible and UV regions, significant stability against detachment, and controlled release of Ag1+ for promising antimicrobial effects.

A novel surgical-prosthetic approach for soft tissue dehiscence coverage around single implant.

OBJECTIVES: The aim of the study was to evaluate soft-tissue coverage and patient aesthetic satisfaction of a novel surgical-prosthetic approach to soft tissue dehiscence (STD) around single endosseous implant. MATERIAL AND METHODS: Twenty patients with buccal soft tissues dehiscence around single implants in the aesthetic area were consecutively enrolled. Treatment consisted in: removal of the implant supported crown, reduction in the implant abutment, coronally advanced flap in combination with connective tissue graft (CTG) and final restoration. The unrestored contralateral tooth normally positioned without recession defect was used as a reference. The soft tissue coverage and patient satisfaction were evaluated 1 year after the final restoration. RESULTS: One-year mean STD coverage was 96.3%, and complete coverage was achieved in 75% of the treated sites. The increase (1.54 ± 0.21 mm) in buccal soft tissue thickness (STT) at 1 year was significantly correlated with CTG thickness at time of the surgery. The mean difference between graft thickness and STT increase was 0.09 ± 0.14 mm, corresponding to the 5.8% of the original graft thickness. The aesthetic analysis showed a significant improvement between the baseline (median, 3.8; 95% CI, 2-4) and the 1-year (median, 8.0; 95% CI, 8-10) visual analogue scale (VAS) scores. CONCLUSION: The results from the present study demonstrated that the proposed bilaminar technique was effective in the coverage of buccal STD around single dental implant and the suggested prosthetic-surgical approach was aesthetically successful.

Root coverage in molar teeth: a comparative controlled randomized clinical trial.

AIM: To compare the clinical outcomes of laterally moved, coronally advanced flap (LMCAF) versus Bilaminar technique (BT) in the treatment of single gingival recession on molar teeth. MATERIAL AND METHODS: Fifty patients showing Miller I and II gingival recessions at first molar teeth were treated: 25 were randomly assigned to the BT group and 25 belonged to the LMCAF group. Patient's post-operative morbidity was assessed 1 week after the surgery, while aesthetic evaluation and the clinical evaluation were made 1 year later. RESULTS: No statistically significant difference was demonstrated in terms of recession and PPD reduction. Statistically greater probability of complete root coverage (CRC, Odds Ratio 22.1) and greater increase in gingival thickness were observed in the BT group. Greater increase in keratinized tissue was obtained in the LMCAF. Patient satisfaction with aesthetics was very high in both treatment groups. Better post-operative course was observed in the LMCAF, while better post-operative sensitivity and root coverage evaluation were demonstrated in patients treated with BT. CONCLUSIONS: Gingival recession at first molar teeth can be successfully treated with LMCAF and BT. Better CRC was achieved with BT, while more comfortable post-operative course was associated with the LMCAF.

Vertically Coronally Advanced Flap (V-CAF) to Increase Vestibule Depth in Mandibular Incisors.

Treatment of gingival recessions affecting mandibular incisors is scarcely documented. Despite a shallow vestibule depth being considered a poor anatomical condition, it has never been measured nor deemed a clinical parameter affecting the outcome of root coverage procedures. This study describes a vertically and coronally advanced flap (V-CAF) + connective tissue graft (CTG) technique to obtain root coverage and increased vestibule depth in the treatment of gingival recessions affecting mandibular incisors. Twenty patients with single gingival recessions were treated. The results showed that V-CAF+CTG is effective in increasing residual vestibule depth and in reducing recession depth. Immediately after surgery, a vestibule-depth increase of 5.9 ± 1.2 mm was reported, which was statistically significant compared to baseline, and it remained stable after 12 months (4.8 ± 1.1 mm). The mean percentage of root coverage was 98.3% ± 5.2% for all treated recessions, and complete root coverage (CRC) was achieved in 90% of cases (18 of 20). V-CAF+CTG could be considered a successful technique in terms of vestibule depth increase and CRC for the treatment of single gingival recessions in the mandibular incisors.

Environmentally Induced Changes of Commercial Carbon Nanotubes in Aqueous Suspensions. Adaptive Behavior of Bacteria in Biofilms.

The effects of environmental factors such as sunlight irradiation and the presence of humic acid (HA) on the physicochemical properties of commercial multiwall carbon nanotubes (MWCNT) suspended in a simulated inorganic matrix (SIM) and their impacts on bacteria growing in biofilms were evaluated. Both solar irradiation and the presence of HA lead to the dissolution of adsorbed metals on the MWCNT, which are residues of synthesis catalysts. Also, preferential adsorption of certain HA components on the MWCNT induces important modifications in the aliphatic/aromatic relationship of HA components in solution and the generation and release of new moieties. Results demonstrated that the variation of such physicochemical parameters strongly affects the interactions of MWCNT with Pseudomonas aeruginosa sessile bacteria. Thus, the number of attached bacteria increased, and stress responses such as decrease in bacterial size were found in the presence of sunlight-irradiated MWCNT with a particular distribution of extracellular polymeric substances (EPS) strands. A shielding effect was observed when HA was added. It was concluded that physicochemical alterations caused by environmental conditions (with/without irradiation, presence/absence of HA) on MWCNT-containing SIM trigger distinctive adaptive behavior of bacteria in biofilms. This information must be taken into account in the development of biologically assisted treatments for organic metal co-contamination of MWCNT-containing media since MWCNT discharge alters the physicochemical properties and composition of the aqueous environment and the response of the biofilms that interact with it.

Patient morbidity and root coverage outcome after subepithelial connective tissue and de-epithelialized grafts: a comparative randomized-controlled clinical trial.

AIMS: The aim of this randomized-controlled clinical trial was to compare the patient morbidity and root coverage outcomes of a coronally advanced flap (CAF) with connective tissue (CTG) or de-epithelialized gingival (DGG) grafts. METHODS: Fifty patients with one recession each were treated. In the control group, the CTG was harvested using the trap-door approach while in the test group the CTG resulted from the de-epithelialization of a free gingival graft. RESULTS: No statistically significant differences were demonstrated between groups in patients's pain killer consumption, post-operative discomfort and bleeding. Lower stress and better ability to chew were demonstrated in the CTG group. Analgesic consumption increased with increasing height of the graft and in the case of dehiscence/necrosis of the primary flap. Pain was negatively correlated with the residual thickness of soft tissue covering the palatal bone. A statistically greater increase in buccal soft tissue thickness was observed in the DGG group. CONCLUSIONS: No differences were demonstrated in the post-operative pain and root coverage outcome in patients subjected to CAF with CTG or DGG.

Characterization and antimicrobial effect of a bioinspired thymol coating formed on titanium surface by one-step immersion treatment.

OBJECTIVE: To develop an antimicrobial and anti-adherent thymol (TOH)-containing coating on titanium (Ti) by a bioinspired one-step biocompatible method. METHODS: A nanolayer of adsorbed TOH (TOH-NL-Ti) was formed by an easy deep coating method on Ti surface. The treatment consists in a simple one-step immersion process in a TOH-containing solution. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), potentiodynamic electrochemical technique, open circuit potential records, Atomic Force Microscopy (AFM) and measurements of TOH release were used to characterize TOH-NL-Ti. Live/Dead staining and plate counting were employed to quantify attached and living adhered bacteria, respectively. Biocompatibility and cytotoxicity in fibroblastic and pre-osteoblastic cell lines were evaluated by acridine orange staining and MTT assay, respectively. RESULTS: TOH adsorbed on TOH-NL-Ti was detected by ATR-FTIR and electrochemical techniques. ATR-FTIR results showed that TOH nanofilms development involves spontaneous production of ketonic structures on Ti surface. AFM analysis revealed that the thickness of the TOH-NL was below 80 nm. Finally, microbiological assays confirmed that TOH-NL-Ti can inhibit the adhesion and kill attached bacteria leading to the eradication of leaving cells on its surface. After 24 h of biocidal release, the antimicrobial effect is also significant (a decrease of 3 orders in the number of attached bacteria). SIGNIFICANCE: The formation of TOH-NL-Ti nanolayer is a simple strategy able to be applied by not specially trained personnel, to reduce implant infection risks, ensure highly effective antimicrobial action and inhibition of bacterial adhesion on Ti surfaces without showing toxic effects for pre-osteoblastic and fibroblastic cells.

Synergistic effect of carboxypterin and methylene blue applied to antimicrobial photodynamic therapy against mature biofilm of Klebsiella pneumoniae.

The control of multidrug-resistant (MDR) bacteria is a growing public health problem, and new strategies are urgently needed for the control of the infections caused by these microorganisms. Notoriously, some MDR microorganisms generate complex structures or biofilms, which adhere to surfaces and confer extraordinary resistance properties that are fundamental challenges to control infections. One of the promising strategies for the control of MDR bacteria is antimicrobial photodynamic therapy (aPDT), which takes advantage of suitable photosensitizers (PS), oxygen and radiation to eradicate microorganisms by the generation of highly reactive species, including reactive oxygen species (ROS) that cause cytotoxic damage and cell death. Habitual aPDT treatments use only methylene blue (MB), but MDR microorganism eradication is not completely achieved. The key result of this study revealed that a combination of two known PSs, 6-carboxypterin (Cap, 100 µM) and MB (2.5-10 µM) exposed to ultraviolet and visible radiation, presents a synergistic effect on the eradication of a MDR Klebsiella pneumoniae strain. Similar effect was observed when the treatment was performed either with planktonic or biofilm growing cells. Moreover, it was found that after treatment the killing action continues in the absence of irradiation leading to the eradication of the microorganisms growing in biofilm. Therefore, the combined aPDT represents a promising strategy for the management of clinical contact surfaces, disinfection of surgical instruments, biofouling and even antimicrobial wastewater treatment.

Effect of degradation products of iron-bioresorbable implants on the physiological behavior of macrophages in vitro.

The degradation of bioresorbable metals in vivo changes the physicochemical properties in the environment of an implant, such as a stent in the artery wall, and may induce the alteration of the functions of the surrounding cells. The Fe-degradation, from bioresorbable stents, is a particularly intricate process because it leads to the release of soluble (SDP) and insoluble degradation products (IDP) of varied composition. Macrophages are involved in the resorption of the exogenous agents coming from degradation of these materials. In the present work an Fe0 ring, made with a pure Fe wire, in contact with macrophage cell cultures was used to simulate the behaviour of a biodegradable Fe-based implant in a biological environment. Non-invasive time-lapse optical microscopy was applied to obtain images of macrophages exposed to Fe-degradation products, without using staining to avoid distortions and artefacts. It was noticed that as metal degraded, the IDP formed in situ accumulated close to the Fe0 ring. In this zone, the macrophages showed a dynamic process of uptake of dark Fe-containing products, confirmed by SEM-EDX. These macrophages showed alterations in the morphology and decrease in the motility and viability. The inability of the macrophages to move and to degrade the engulfed products caused a long persistence of IDP in the zone closest to the metal. The deleterious effects of IDP accumulated close to the ring, were significantly worse than those observed in the experiments made with (1) concentrated salt solutions (Fe3+ salt 3 mM), with the same amount of precipitates but uniformly distributed in the well, and (2) diluted salt solutions (Fe3+ salt 1 mM) with mainly soluble species. The results were confirmed by standard staining protocols that revealed dead cells close to the Fe0 ring and oxidative stress in cells exposed to both soluble and insoluble species.

Influence of surface sub-micropattern on the adhesion of pioneer bacteria on metals.

Most of the implantable medical devices are prone to infection caused by microorganisms that form biofilms. Pseudomonads are frequently used as model species for studying bacterial adhesion. The initial stages of biofilm formation are influenced by different factors including, among others, the chemistry of the surface, the roughness, and topography. The aim of this work was to assess the early stages of Pseudomonas fluorescens biofilm formation on sub-microstructured surfaces (SMS) that are in tune with bacterial size. Copper and gold were used as the substrata. It was concluded that SMS influenced bacterial length, alignment, and distribution, whereas the chemistry of the surfaces affected bacterial length and distribution. However, the effect of the SMS was the most significant. The shape of the bacterial colonies and the polymeric substances production were also influenced by SMS and the chemistry of the surface and both factors may be considered to reduce the susceptibility of a surface to biofilm formation.

Osseous resective surgery: long-term case report.

This case report evaluated the long-term effects of osseous resective therapy in the treatment of a patient with moderately advanced periodontal disease. In 1984, the patient underwent initial therapy followed by a periodontal surgical phase consisting of osseous recontouring with an apically positioned flap. After 20 years, in 2003, the patient presented with a traumatic complication. An exploratory surgery revealed a fracture on the roof of the pulp chamber on the maxillary left first molar. The buccal roots were resected, preserving the palatal root, and a reevaluation of the long-term outcome of osseous resective surgery was performed. It is suggested that the positive treatment result is the consequence of the reestablishment of tissue morphology favorable for oral hygiene and plaque control by the patient.