Using Antimicrobial Photodynamic Therapy with Ultrasound Devices and Bioactive Glasses as a Combined Approach for Treating Dentin Caries Lesions.

Novel approaches for caries lesion removal and treatment have been proposed. This study evaluates the combined use of an experimental ultrasound, aPDT (antimicrobial photodynamic therapy) and bioactive glasses on the removal, decontamination and remineralization of dentin caries lesions. A biological model created with a duo species biofilm (Streptococcus mutans and Lactobacillus acidophilus) was used for the development of a caries-like lesion over the dentin for 7 days. Bovine dentin specimens (4 × 4 × 2 mm) were randomized according to the following caries removal techniques: bur (BUR) or ultrasound (ULT), decontamination (with or without aPDT) and remineralization materials (45S5 or F18 bioactive glasses). The following different groups were investigated: caries lesion (control); sound dentin (control); BUR; BUR + aPDT; ULT; ULT + aPDT; BUR + 45S5, BUR + F18; ULT + 45S5; ULT + F18; BUR + aPDT + 45S5; BUR + aPDT + F18; ULT + aPDT + 45S5; and ULT + aPDT + F18. Transverse microradiography (TMR), cross-sectional microhardness (CSH), FT-Raman spectroscopy and confocal microscopy (CLSM) were performed. A two-way ANOVA and Tukey's test were used (α = 0.05). (3) Results: The TMR revealed a lesion depth of 213.9 ± 49.5 µm and a mineral loss of 4929.3% vol.µm. The CSH increases as a function of depth, regardless of the group (p < 0.05). Removal with BUR (24.40-63.03 KHN) has a greater CSH than ULT (20.01-47.53 KHN; p < 0.05). aPDT did not affect the CSH (p > 0.05). No difference was observed between 45S5 or F18 (p > 0.05), but a change was observed for ULT (p > 0.05). The FT-Raman shows no differences for the phosphate (p > 0.05), but a difference is observed for the carbonate and C-H bonds. The CLSM images show that aPDT effectively inactivates residual bacteria. A combination of ULT, aPDT and bioactive glasses can be a promising minimally invasive treatment.

Effect of Biosilicate® Addition on Physical-Mechanical and Biological Properties of Dental Glass Ionomer Cements.

This study investigated the influence of incorporating Biosilicate® on the physico-mechanical and biological properties of glass ionomer cement (GIC). This bioactive glass ceramic (23.75% Na2O, 23.75% CaO, 48.5% SiO2, and 4% P2O5) was incorporated by weight (5%, 10%, or 15%) into commercially available GICs (Maxxion R and Fuji IX GP). Surface characterization was made by SEM (n = 3), EDS (n = 3), and FTIR (n = 1). The setting and working (S/W time) times (n = 3) and compressive strength (CS) were analyzed (n = 10) according to ISO 9917-1:2007. The ion release (n = 6) was determined and quantified by ICP OES and by UV-Vis for Ca, Na, Al, Si, P, and F. To verify cell cytotoxicity, stem cells from the apical papilla (SCAP) were exposed to eluates (n = 3, at a ratio of 1.8 cm2/mL) and analyzed 24 h post-exposure. Antimicrobial activity against Streptococcus mutans (ATCC 25175, NCTC 10449) was analyzed by direct contact for 2 h (n = 5). The data were submitted for normality and lognormality testing. One-way ANOVA and Tukey's test were applied for the working and setting time, compressive strength, and ion release data. Data from cytotoxicity and antimicrobial activity were submitted for Kruskal-Wallis' testing and Dunn's post hoc test (α = 0.05). Among all experimental groups, only those with 5% (wt) of Biosilicate® showed better surface quality. Only M5% showed a comparable W/S time to the original material (p = 0.7254 and p = 0.5912). CS was maintained for all Maxxion R groups (p > 0.0001) and declined for Fuji IX experimental groups (p < 0.0001). The Na, Si, P, and F ions released were significantly increased for all Maxxion R and Fuji IX groups (p < 0.0001). Cytotoxicity was increased only for Maxxion R with 5% and 10% of Biosilicate®. A higher inhibition of S. mutans growth was observed for Maxxion R with 5% of Biosilicate® (less than 100 CFU/mL), followed by Maxxion R with 10% of Biosilicate® (p = 0.0053) and Maxxion R without the glass ceramic (p = 0.0093). Maxxion R and Fuji IX presented different behaviors regarding Biosilicate® incorporation. The impacts on physico-mechanical and biological properties were different depending on the GIC, but therapeutic ion release was increased for both materials.

Impact of silanization of different bioactive glasses in simplified adhesives on degree of conversion, dentin bonding and collagen remineralization.

OBJECTIVE: To analyze simplified adhesive containing pure or silanized bioglass 45S5 (with calcium) or Sr-45S5 (strontium-substituted) fillers applied on dentin and to evaluate the microtensile bond strength (µTBS), interface nanoleakage, degree of conversion of adhesive, collagen degradation and remineralization. METHODS: Ambar Universal adhesive (FGM) was doped with 10 wt% bioactive glasses to form following groups: Control (no bioglass), 45S5 (conventional bioglass 45S5), Sr-45S5 (Sr-substituted bioglass 45S5), Sil-45S5 (silanized bioglass 45S5) and Sil-Sr-45S5 (silanized bioglass Sr-45S5). Adhesives were applied after dentin acid-etching using phosphoric acid at extracted human molars. Resin-dentin sticks were obtained and tested for µTBS, nanoleakage at 24 h or 6 months. Degree of conversion was measured using micro-Raman spectroscopy. Dentin remineralization was assessed by FTIR after 6-month storage in PBS. Hydroxyproline (HYP) release was surveyed by UV-Vis spectroscopy. Statistical analysis was performed using ANOVA and Tukey's test (p < 0.05). RESULTS: Regarding µTBS, Sr-45S5 and 45S5 presented higher and stable results (p > 0.05). Control (p = 0.018) and Sil-Sr-45S5 (p < 0.001) showed µTBS reduction after 6-month aging. Sil-Sr-45S5 showed higher HYP release than that obtained in the 45S5 group. Sil-45S5 showed mineral deposition and increase in µTBS (p = 0.028) after 6-months. All experimental adhesives exhibited higher degree of conversion compared to Control group, except for 45S5. All adhesives created gap-free interfaces, with very low silver impregnation, except for Sil-Sr-45S5. SIGNIFICANCE: The incorporation of silanized 45S5 bioglass into the universal adhesive was advantageous in terms of dentin remineralization, bonding performance and adhesive polymerization. Conversely, Sil-Sr-45S5 compromised the µTBS, interface nanoleakage and had a negative impact on HYP outcomes.

Effect of bioactive glasses used as dentin desensitizers on the dentin-pulp complex in rats.

Bioactive glasses have been recommended for the occlusion of dentinal tubules in treating cervical dentin hypersensitivity. This study evaluates an in vivo model of dentin exposure, and tests the efficacy of bioglass treatments. Thirty male Wistar rats received gingival recession surgery on the upper left first molar. The treatments were applied over the surface of the exposed dentin every 4 days for 28 days. The groups were as follows: Naive; Gingival recession; Cavity varnish; Biosilicate®; Strontium bioglass; and Potassium bioglass. Changes in the dentin-pulp complex, and the presence of substance P, were evaluated through hematoxylin-eosin and immunohistochemical staining. The groups had similar results. Teeth with exposed dentinal tubules in rats showed a typical pattern in the dentin-pulp complex and immunotracing for substance P. The materials did not cause pulp damage. The effects of gingival recession and open dentinal tubules on pulp tissue require further clarification.

Effect of bioactive glasses containing strontium and potassium on dentin permeability.

Dentin hypersensitivity (DH) is characterized by pain caused by an external stimulus on exposed dentin. Different therapeutic approaches have been proposed to mitigate this problem; however, none of them provide permanent pain relief. In this study, we synthesized and characterized experimental bioactive glasses containing 3.07 mol% SrO or 3.36 mol% K2 O (both equivalent to 5 wt% in the glass), and evaluated their effect on dentin permeability to verify their potential to treat DH. The experimental materials were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, micro-Raman spectroscopy, and X-ray diffraction to confirm the respective structures and chemical compositions. The reduction in the hydraulic conductance of dentin was evaluated at the three stages: minimum permeability; maximum permeability (24% ethylenediaminetetraacetic acid [EDTA] treatment); and final dentin permeability after treatment with the bioactive glasses. They all promoted a reduction in dentin permeability, with a significant difference for each sample and posttreatment group. Also, a significant reduction in dentin permeability was observed even after a simulated toothbrushing test, demonstrating effective action of these materials against DH. Besides, incorporating 3.07 mol% SrO was a positive factor. Therefore, strontium's desensitizing and re-mineralizing properties can be further exploited in bioactive glasses to promote a synergistic effect to treat DH.

Surface properties of a new lithium disilicate glass-ceramic after grinding.

This study aimed to evaluate the effect of grinding on some surface properties of two lithium disilicate-based glass-ceramics, one experimental new product denominated LaMaV Press (UFSCar-Brazil) and another commercial known as IPS e-max Press (Ivoclar), in the context of simulated clinical adjustment. Discs (N = 24, 12 mm in diameter) were separated into four groups: LaMaV Press with no grinding (E), LaMaV Press after grinding (EG), IPS e-max Press with no grinding (C), and IPS e-max Press after grinding (CG). A 0.1-mm deep grinding was carried out on EG and CG samples (final thickness of 1.4 mm) using a diamond stone in a low-speed device. The E and C samples had the same thickness. The effect of grinding on the sample surfaces was evaluated by X-ray diffraction, mechanical and optical profilometry, scanning electron microscopy, goniometry, and Vickers hardness. The mean roughness (Ra) was evaluated by Kruskal-Wallis and Student-Newman-Keuls statistics. The surface energy (SE) by the sessile drop method and Vickers hardness (VH) were analyzed using two-way ANOVA. The Ra medians were E = 1.69 µm, EG = 1.57 µm, C = 1.45 µm, and CG = 1.13 µm with p = 0.0284. The SE and VH were similar for all materials and treatments. Grinding smoothed the surfaces and did not significantly alter the hardness and surface energy of both LaMaV Press and IPS e-max Press. These glass-ceramics presented similar surface properties, and clinical adjustments can be implemented without loss of performance of both materials. A grinding standardization device developed that allowed to control the amount of grinding, the speed of rotation speed and the force exerted on the samples.

Analysis of permeability and biological properties of dentin treated with experimental bioactive glasses.

OBJECTIVES: To evaluate obliterating capability and biological performance of desensitizing agents. METHODS: 50 dentin blocks were distributed according to the desensitizing agent used (n = 10): Control (Artificial saliva); Ultra EZ (Ultradent); Desensibilize Nano P (FGM); T5-OH Bioactive Glass (Experimental solution); F18 Bioactive Glass (Experimental solution). Desensitizing treatments were performed for 15 days. In addition, specimens were subjected to acid challenge to simulate oral environment demineralizing conditions. Samples were subjected to permeability analysis before and after desensitizing procedures and acid challenge. Cytotoxicity analysis was performed by using Alamar Blue assay and complemented by total protein quantification by Pierce Bicinchoninic Acid assay at 15 min, 24-h and 48-h time points. Scanning electron microscopy and energy dispersion X-ray spectroscopy were performed for qualitative analysis. Data of dentin permeability was analyzed by two-way repeated measures ANOVA and Tukey's test. For cytotoxicity, Kruskal-Wallis and Newman-Keuls tests. RESULTS: for dentin permeability there was no significant difference among desensitizing agents after treatment, but control group presented highest values (0.131 ± 0.076 Lp). After acid challenge, control group maintained highest values (0.044 ± 0.014 Lp) with significant difference to other groups, except for Desensibilize Nano P (0.037 ± 0.019 Lp). For cytotoxicity, there were no significant differences among groups. CONCLUSION: Bioglass-based desensitizers caused similar effects to commercially available products, regarding permeability and dentin biological properties. CLINICAL SIGNIFICANCE: There is no gold standard protocol for dentin sensitivity. The study of novel desensitizing agents that can obliterate dentinal tubules in a faster-acting and long-lasting way may help meet this clinical need.

Bactericidal activity and biofilm inhibition of F18 bioactive glass against Staphylococcus aureus.

Antimicrobial treatment failure has been increasing at alarming rates. In this context, the bactericidal properties of biocompatible antimicrobial agents have been widely studied. F18 is a recently developed bioactive glass that presents a much wider working range when compared to other bioactive glasses, a feature that allows it to be used for coating metallic implants, sintering scaffolds or manufacturing fibers for wound healing applications. The aim of this study was to investigate the in vitro bactericidal and anti-biofilm activity of F18 glass as a powder and as a coating on steel samples, and to explore the effects of its dissolution products at concentrations from 3 mg/mL to 50 mg/mL against the Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Furthermore, we intend to verify whether changes in the medium pH could influence the bactericidal activity of F18. The results indicated that F18 presented bactericidal activity in preformed S. aureus and MRSA biofilms, reducing more than 6 logs of the viable cells that remained in contact with 50 mg/mL for 24 h. Moreover, an anti-biofilm activity was observed after 12 h of direct contact, with a drop of more than 6 logs of the viable bacterial population. Neutralization of the F18 solution pH decreased its bactericidal efficacy. These results indicate that the F18 glass could be considered as an alternative material for controlling and treating infections by S. aureus.

Biocompatibility, Biomineralization, and Maturation of Collagen by RTR®, Bioglass and DM Bone® Materials.

This study evaluated the biocompatibility, biomineralization, and collagen fiber maturation induced by Resorbable Tissue Replacement (RTR®; ß-tricalcium phosphate [TCP]), Bioglass (BIOG; bioactive glass), and DM Bone® (DMB; hydroxyapatite and ß-TCP) in vivo. Sixty-four polyethylene tubes with or without (control group; CG) materials (n=8/group/period) were randomly implanted in the subcutaneous tissue of 16 male Wistar rats (four per rat), weighting 250 to 280 g. The rats were killed after 7 and 30 days (n=8), and the specimens were removed for analysis of inflammation using hematoxylin-eosin; biomineralization assay using von Kossa (VK) staining and polarized light (PL); and collagen fiber maturation using picrosirius red (PSR). Nonparametric data were statistically analyzed by Kruskal-Wallis and Dunn tests, and parametric data by one-way ANOVA test (p<0.05). At 7 days, all groups induced moderate inflammation (p>0.05). At 30 days, there was mild inflammation in the BIOG and CG, and moderate inflammation in the RTR and DMB groups, with a significant difference between the CG and RTR (p<0.05). The fibrous capsule was thick at 7 days and predominantly thin at 30 days in all groups. All materials exhibited structures that stained positively for VK and PL. Immature collagen fibers were predominant at 7 and 30 days in all groups (p>0.05), although DMB exhibited more mature fibers than BIOG at 30 days (p<0.05). RTR, BIOG, and DMB were biocompatible, inducing inflammation that reduced over time and biomineralization in the subcutaneous tissue of rats. DMB exhibited more mature collagen fibers than BIOG over a longer period.

Biofilm Formation and Expression of Virulence Genes of Microorganisms Grown in Contact with a New Bioactive Glass.

Bioactive glass F18 (BGF18), a glass containing SiO2-Na2O-K2O-MgO-CaO-P2O5, is highly effective as an osseointegration buster agent when applied as a coating in titanium implants. Biocompatibility tests using this biomaterial exhibited positive results; however, its antimicrobial activity is still under investigation. In this study we evaluated biofilm formation and expression of virulence-factor-related genes in Candida albicans, Staphylococcus epidermidis, and Pseudomonas aeruginosa grown on surfaces of titanium and titanium coated with BGF18. C. albicans, S. epidermidis, and P. aeruginosa biofilms were grown on specimens for 8, 24, and 48 h. After each interval, the pH was measured and the colony-forming units were counted for the biofilm recovery rates. In parallel, quantitative real-time polymerase chain reactions were carried out to verify the expression of virulence-factor-related genes. Our results showed that pH changes of the culture in contact with the bioactive glass were merely observed. Reduction in biofilm formation was not observed at any of the studied time. However, changes in the expression level of genes related to virulence factors were observed after 8 and 48 h of culture in BGF18. BGF18 coating did not have a clear inhibitory effect on biofilm growth but promoted the modulation of virulence factors.

Biocompatibility, biomineralization, and maturation of collagen by rtr®, bioglass and dm bone® materials

Abstract This study evaluated the biocompatibility, biomineralization, and collagen fiber maturation induced by Resorbable Tissue Replacement (RTR®; β-tricalcium phosphate [TCP]), Bioglass (BIOG; bioactive glass), and DM Bone® (DMB; hydroxyapatite and β-TCP) in vivo. Sixty-four polyethylene tubes with or without (control group; CG) materials (n=8/group/period) were randomly implanted in the subcutaneous tissue of 16 male Wistar rats (four per rat), weighting 250 to 280 g. The rats were killed after 7 and 30 days (n=8), and the specimens were removed for analysis of inflammation using hematoxylin-eosin; biomineralization assay using von Kossa (VK) staining and polarized light (PL); and collagen fiber maturation using picrosirius red (PSR). Nonparametric data were statistically analyzed by Kruskal-Wallis and Dunn tests, and parametric data by one-way ANOVA test (p<0.05). At 7 days, all groups induced moderate inflammation (p>0.05). At 30 days, there was mild inflammation in the BIOG and CG, and moderate inflammation in the RTR and DMB groups, with a significant difference between the CG and RTR (p<0.05). The fibrous capsule was thick at 7 days and predominantly thin at 30 days in all groups. All materials exhibited structures that stained positively for VK and PL. Immature collagen fibers were predominant at 7 and 30 days in all groups (p>0.05), although DMB exhibited more mature fibers than BIOG at 30 days (p<0.05). RTR, BIOG, and DMB were biocompatible, inducing inflammation that reduced over time and biomineralization in the subcutaneous tissue of rats. DMB exhibited more mature collagen fibers than BIOG over a longer period.

Resumo Este estudo avaliou a biocompatibilidade, biomineralização e maturação das fibras de colágeno induzidas por Resorbable Tissue Replacement (RTR®; fosfato β-tricálcico [TCP]), Bioglass (BIOG; vidro bioativo) e DM Bone® (DMB; hidroxiapatita e β-TCP) in vivo. Sessenta e quatro tubos de polietileno com ou sem (grupo controle; GC) os materiais (n=8/grupo/período) foram implantados aleatoriamente em tecido subcutâneo de 16 ratos machos Wistar (quatro por rato), pesando entre 250 a 280g. Os ratos foram mortos após 7 e 30 dias (n=8), e as amostras foram removidas para análise da inflamação utilizando hematoxilina-eosina; avaliação da biomineralização utilizando coloração de von Kossa (VK) e luz polarizada (LP); e maturação das fibras colágenas, utilizando picrosirius red (PSR). Os dados não-paramétricos foram analisados pelos testes de Kruskal-Wallis e Dunn, e os paramétricos pelo teste de one-way ANOVA (p<0.05). Aos 7 dias, todos os grupos induziram inflamação moderada (p>0,05). Aos 30 dias, houve inflamação leve nos grupos BIOG e GC, e inflamação moderada nos grupos RTR e DMB, com diferença significativa entre os GC e RTR (p<0,05). A cápsula fibrosa foi espessa aos 7 dias, e predominantemente fina aos 30 dias em todos os grupos. Todos os materiais exibiram estruturas positivas para VK e LP. Fibras colágenas imaturas foram predominantes aos 7 e 30 dias em todos os grupos (p>0,05), embora o DMB exibiu fibras mais maduras do que o BIOG aos 30 dias (p<0,05). RTR, BIOG e DMB foram biocompatíveis, induzindo inflamação que reduziu com o tempo, e biomineralização no tecido subcutâneo de ratos. O DMB exibiu mais fibras colágenas maduras do que o BIOG em período mais longo.

Conical Biosilicate Implant for Volume Augmentation in Anophthalmic Sockets.

The ideal implant for anophthalmic socket reconstruction has yet to be developed. Biosilicate, a highly bioactive glass-ceramic, has been used in the composition of conical implants, which were initially tested in rabbit orbits with excellent results. However, the use of this material and the conical shape of the implants require further study in the human anophthalmic socket. Thus, we propose the use of a new conical implant composed of Biosilicate for orbital volume augmentation in anophthalmic sockets. This prospective, randomized study included 45 patients receiving conical implants composed of either Biosilicate or polymethylmethacrylate (control). Patients were evaluated clinically before and 7, 30, 60, 120, and 180 days after implantation. Systemic evaluations, laboratory tests, and computed tomography of the orbits were performed preoperatively and 180 days postoperatively. Both groups had good outcomes with no significant infectious or inflammatory processes. Only 1 patient, in the Biosilicate group, had early implant extrusion. Laboratory tests were normal in both groups. Computed tomography scans showed that the implants in both groups were well positioned. The new conical implant composed of Biosilicate was successfully used for anophthalmic socket reconstruction. This implant may provide a good alternative to the only conical implant currently available on the market, which is composed of porous polyethylene.

Experimental gel containing bioactive glass-ceramic to minimize the pulp damage caused by dental bleaching in rats.

OBJECTIVES: This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2). METHODOLOGY: The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). RESULTS: At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). CONCLUSION: A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.

Marine spongin incorporation into Biosilicate® for tissue engineering applications: An in vivo study.

Biomaterials and bone grafts, with the ability of stimulating tissue growth and bone consolidation, have been emerging as very promising strategies to treat bone fractures. Despite its well-known positive effects of biosilicate (BS) on osteogenesis, its use as bone grafts in critical situations such as bone defects of high dimensions or in non-consolidated fractures may not be sufficient to stimulate tissue repair. Consequently, several approaches have been explored to improve the bioactivity of BS. A promising strategy to reach this aim is the inclusion of an organic part, such as collagen, in order to mimic bone structure. Thus, the present study investigated the biological effects of marine spongin (SPG)-enriched BS composites on the process of healing, using a critical experimental model of cranial bone defect in rats. Histopathological and immunohistochemistry analyzes were performed after two and six weeks of implantation to investigate the effects of the material on bone repair (supplemental material-graphical abstract). Histological analysis demonstrated that for both BS and BS/SPG, similar findings were observed, with signs of material degradation, the presence of granulation tissue along the defect area and newly formed bone into the area of the defect. Additionally, histomorphometry showed that the control group presented higher values for Ob.S/BS (%) and for N.Ob/T.Ar (mm2) (six weeks post-surgery) compared to BS/SPG and higher values of N.Ob/T.Ar (mm2) compared to BS (two weeks post-surgery). Moreover, BS showed higher values for OV/TV (%) compared to BS/SPG (six weeks post-surgery). Also, VEGF immunohistochemistry was increased for BS (two weeks post-surgery) and for BS/SPG (six weeks) compared to CG. TGFb immunostaining was higher for BS compared to CG. The results of this study demonstrated that the BS and BS/SPG scaffolds were biocompatible and able to support bone formation in a critical bone defect in rats. Moreover, an increased VEGF immunostaining was observed in BS/SPG.

Biomaterials for orthopedics: anti-biofilm activity of a new bioactive glass coating on titanium implants.

This study evaluated adhesion and biofilm formation by Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis on surfaces of titanium (Ti) and titanium coated with F18 Bioactive Glass (BGF18). Biofilms were grown and the areas coated with biofilm were determined after 2, 4 and 8 h. Microscopy techniques were applied in order to visualize the structure of the mature biofilm and the extracellular matrix. On the BGF18 specimens, there was less biofilm formation by C. albicans and S. epidermidis after incubation for 8 h. For P. aeruginosa biofilm, a reduction was observed after incubation for 4 h, and it remained reduced after 8 h on BGF18 specimens. All biofilm matrices seemed to be thicker on BGF18 surface than on titanium surfaces. BGF18 showed significant anti-biofilm activity in comparison with Ti in the initial periods of biofilm formation; however, there was extensive biofilm after incubation for 48 h.

Experimental gel containing bioactive glass-ceramic to minimize the pulp damage caused by dental bleaching in rats

Abstract Objectives This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2). Methodology The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). Results At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). Conclusion A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.

Scaffolds of bioactive glass-ceramic (Biosilicate®) and bone healing: A biological evaluation in an experimental model of tibial bone defect in rats.

This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a model of tibial bone defect. Sixty male Wistar rats were distributed into bone defect control group (CG) and Biosilicate® scaffold group (BG).  Animals were euthanized 15, 30 and 45 days post-surgery. Stereomicroscopy, scanning electron microscopy, histopathological, immunohistochemistry and biomechanical analysis were used. Scaffolds had a total porosity of 44%, macroporosity of 15% with pore diameter of 230 µm. Higher amount of newly formed bone was observed on days 30 and 45 in BG. Immunohistochemistry analysis showed that the COX-2 expression was significantly higher on days 15 and 30 in BG compared with the CG. RUNX-2 immunoexpression was significantly higher in BG on days 15 and 45. No statistically significant difference was observed in RANKL immunoexpression in all experimental groups. BMP-9 immunoexpression was significantly upregulated in the BG on day 45. Biomechanical analysis showed a decrease in the biomechanical properties of the bone callus on days 30 and 45. The implantation of the Biosilicate® scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair.

Effect of titanium surface functionalization with bioactive glass on osseointegration: An experimental study in dogs.

PURPOSE: The purpose of this study was to evaluate the effect of surface functionalization with bioactive glass BSF18 on the osseointegration of sandblasted and dual acid-etched surface (AE) implants. METHODS AND MATERIALS: Forty Morse taper implants with an AE surface as controls (C) or with an AE surface functionalized with BSF18 (BF) were placed in the mandibles of 10 beagles. Implants were analyzed after 2 and 4 weeks of healing. Implant stability quotient (ISQ) values were registered immediately after installation and prior to sacrifice. Samples were analyzed for bone-to-implant contact (BIC) and bone density (BD). The characterization of BF implants included surface roughness analysis with atomic force microscopy and contact angle (CA) analysis to evaluate wettability. Data were analyzed using two-way ANOVA followed by Tukey's test (p < 0.05). RESULTS: Surface roughness was not affected by BF treatment. CA was lower in the BF group compared to the C group. No significant difference was observed in ISQ values between surfaces (p = 0,231), irrespective of time. Significantly higher ISQ values were observed for both implants after 4 weeks when compared with baseline (p = 0.04). Significantly higher BIC (p = 0.011) and BD (p = 0.025) values were observed for the BF compared to the C group at 2 weeks. Significantly higher BIC (p = 0.030) and BD (p = 0.015) values for the C group were observed at 4 weeks compared to 2 weeks. No significant difference was observed in the BF group between 2 and 4 weeks. CONCLUSIONS: Implant functionalization with BSF18 improved the wettability of the implant surface; enhancing BIC and BD at 2 weeks.

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses-A 45-Year Overview.

X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses.

Effect of a Bioactive Glass Ceramic on the Control of Enamel and Dentin Erosion Lesions.

This study evaluated the effect of a bioactive glass ceramic for the control of erosion and caries lesions. Fragments (n=10) of bovine enamel and root dentin received daily application of different treatments (Biosilicate; Acidulated Phosphate Fluoride- APF; Untreated - control) during the performance of erosive cycles. Surfaces were analyzed with 3D optical profilometry to quantify the superficial loss in four periods (1, 7, 14 and 21 days), as well as the lesion depth with confocal laser scanning microscopy. For caries progression assessment, initial Knoop microhardness was measured on enamel bovine fragments. Initial carious lesions were developed and specimens were divided into three groups (n=10), according to the daily topical application (Biosilicate; APF; no application - control), during the de-remineralization cycles for 14 days. Final microhardness was obtained to calculate the change of surface microhardness. Subsurface demineralization was analyzed using cross-sectional microhardness (depths 10, 30, 50, 70, 90, 110 and 220 µm). Data were tested using ANOVA and Tukey's test (a=5%). Results of erosive evaluation showed that Biosilicate promoted the lowest (p<0.05) values of surface loss, regardless of time, for both enamel and dentin; APF promoted lower (p<0.05) surface loss than control; analyzing different periods of time, APF did not show difference (p>0.05) between 14 and 21 days of demineralization. Results of enamel caries assessment showed that Biosilicate resulted in higher (p<0.05) surface and subsurface microhardness than both APF and control-applications. It may be concluded that Biosilicate application showed a higher potential to reduce surface loss and development of erosion and caries lesions.