Showing papers by "Fabrício Mezzomo Collares published in 2020"
TL;DR: There is an urgent need for improved biological efficacy studies in resin-based restorative dental materials containing antibacterial additives and to develop standardized methods to help understand and optimize these materials.
36 citations
TL;DR: Sol-gel-derived bioactive glasses promoted increased mineral deposition and cell viability for experimental adhesives with increased phosphate content and longitudinal μTBS values for the ABAGNb group, suggesting the potential of the studied particles to be applied as bioactive fillers for dental adhesive.
23 citations
TL;DR: P pH-responsive calcium and phosphate-ion releasing sealants with antimicrobial and rechargeable properties may be a reliable complementary approach for caries management.
22 citations
TL;DR: The dental sealant formulations formulated herein with dual functions and purpose for biointeractivity to prevent biofilm formation and mineral loss can be a reliable complementary strategy to decrease the incidence of carious lesions in children at a high risk of caries.
Abstract: Dental caries in children is a leading worldwide oral health concern. Combining antibacterial and remineralizing additives within dental sealants is a promising approach for caries prevention. Saliva contains oral bacteria that are indicative of the whole oral microbiome and may have the ability to reflect the dysbiosis present in patients with dental caries. Here, we used the saliva of children at a low and high risk of caries to culture microcosm biofilms resembling caries-associated microbial communities and investigated the changes in the biofilms promoted by the formulated dental sealants containing dimethylaminohexadecyl methacrylate (DMAHDM), a quaternary ammonium monomer, and nanoparticles of amorphous calcium phosphate (NACP). Ten volunteers were selected from each caries-risk condition for saliva collection. Biofilms were grown on the tested sealant samples using a 48 h-microcosm biofilm model. The biofilm growth, metabolic behavior, and bacterial acid production were combined with 16S rRNA sequencing analysis for the assessment of the biofilm grown over the material. The DMAHDM-NACP dental sealant formulations promoted a significant reduction in the population of mutans streptococci, total streptococci, lactobacilli, and total microorganisms in the biofilms regardless of the risk status of the donor child's saliva (p < 0.05). Metabolic and lactic acid production was greatly reduced when in contact with the DMAHDM-NACP sealants in both the sources of inoculum. The relative abundance of the Streptococcus genera derived from patients at a high risk of caries was reduced on contact with the antibacterial sealant. The dental sealant formulations were effective in modulating the growth of the biofilm derived from the saliva of children at a low and high risk of caries. The sealants formulated herein with dual functions and purpose for biointeractivity to prevent biofilm formation and mineral loss can be a reliable complementary strategy to decrease the incidence of carious lesions in children at a high risk of caries.
21 citations
TL;DR: The addition of METAC provided antibacterial activity to the experimental resin–based sealant and is an effective quaternary ammonium compound as an antibacterial agent for resin-based sealants without cytotoxic effects against human keratinocytes.
Abstract: The aim of this study was to evaluate the influence of [2-(methacryloyloxy)ethyl] trimethylammonium chloride (METAC) in the physico-chemical properties, antibacterial activity and cytotoxicity of an experimental resin–based sealant. An experimental resin-based sealant was formulated with dimethacrylates and a photoinitiator system. METAC was added at 2.5 wt.% (G2.5%) and 5 wt.% (G5%) into the experimental resin–based sealant, and one group remained without METAC as control (GCTRL). The resin-based sealants were analysed for polymerization behaviour and degree of conversion (DC), Knoop hardness (KHN) and softening in solvent (ΔKHN), ultimate tensile strength (UTS), contact angle, surface free energy (SFE), immediate and long-term micro-shear bond strength (μ-SBS) and antibacterial activity and cytotoxicity against human keratinocytes. The experimental resin–based sealants presented different polymerization behaviours without significant differences in the DC (p > 0.05). There was no significant difference for initial KHN (p > 0.05). The ΔKHN ranged from 51.62 (±3.70)% to 62.40 (±4.14)%, with higher values for G5% (p 0.05). There were no significant differences for UTS, contact angle and SFE among groups (p > 0.05). G2.5% and G5% presented immediate and long-term antibacterial activity (p 0.05). The addition of METAC provided antibacterial activity to the experimental resin–based sealant. METAC is an effective quaternary ammonium compound as an antibacterial agent for resin-based sealants without cytotoxic effects against human keratinocytes.
18 citations
TL;DR: The addition of 0.5 wt % of myristyltrimethylammonium bromide did not alter the physical and chemical properties of the dental resin and provided antibacterial activity without cytotoxic effect.
Abstract: This in vitro study evaluated the effect of myristyltrimethylammonium bromide (MYTAB) on the physical, chemical, and biological properties of an experimental dental resin. The resin was formulated with dental dimetacrylate monomers and a photoinitiator/co-initiator system. MYTAB was added at 0.5 (G0.5%), 1 (G1%), and 2 (G2%) wt %, and one group remained without MYTAB and was used as the control (GCtrl). The resins were analyzed for the polymerization kinetics, degree of conversion, ultimate tensile strength (UTS), antibacterial activity against Streptococcus mutans, and cytotoxicity against human keratinocytes. Changes in the polymerization kinetics profiling were observed, and the degree of conversion ranged from 57.36% (±2.50%) for G2% to 61.88% (±1.91%) for G0.5%, without a statistically significant difference among groups (p > 0.05). The UTS values ranged from 32.85 (±6.08) MPa for G0.5% to 35.12 (±5.74) MPa for GCtrl (p > 0.05). MYTAB groups showed antibacterial activity against biofilm formation from 0.5 wt % (p 0.05). In conclusion, the addition of 0.5 wt % of MYTAB did not alter the physical and chemical properties of the dental resin and provided antibacterial activity without cytotoxic effect.
15 citations
11 Aug 2020
TL;DR: The antimicrobial effects of aPDT with nano-based platforms on oral bacterial disinfection will help to advance the design of combination strategies that increase the rate of complete and durable clinical response in oral infections.
Abstract: Objective: This review clusters the growing field of nano-based platforms for antimicrobial photodynamic therapy (aPDT) targeting pathogenic oral biofilms and increase interactions between dental r...
14 citations
TL;DR: Niobium silicate particles may be used as an alternative inorganic filler to achieve an adequate balance between physical-chemical and biological properties for the development of bioactive composite resins.
13 citations
TL;DR: Sol-gel derived CS particles developed with potential to applied for the production of bioactive ceramic cements with adequate properties and bioactivity being an alternative for regenerative endodontic treatments are evaluated.
13 citations
TL;DR: Experimental dental adhesives containing cerium dioxide (CeO2) were formulated and CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dentalAdhesives.
Abstract: The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives' radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.
13 citations
TL;DR: The physicochemical properties of adhesives were not affected by SKT incorporation, and the filler provided antibacterial activity against S. mutans without changes in the pulp cells' viability, suggesting this hybrid zinc-based particle with ionic liquid coating may be a promising filler to improve dental restorations.
TL;DR: The results indicated that the denture liners preserved their mechanical property after the maximum contact time with the solution at the highest tested concentration, and the PHMGH aqueous solutions at 0.125 wt% could be applied to promote interim denture liner disinfection without promoting the loss of materials’ mechanical property.
TL;DR: The investigated sealing material holds valuable dual antibacterial and antifungal activities associated with a reduced mineral loss against the cariogenic challenge promoted by ECC key pathogens.
Abstract: Herein, we investigated a biointeractive tooth sealing material consisted of dimethylaminohexadecyl methacrylate (DMAHDM) and amorphous calcium phosphate nanoparticles (NACPs) to address the above issues simultaneously Of note, 5% DMAHDM was incorporated into the resin blend, and 20% NACP was added to inorganic filler content of dental formulations intended as dental sealants The sealing materials were used to seal human extracted teeth The sealed teeth were subjected to an early childhood caries (ECC) key pathogen (Candida albicans and Streptococcus mutans) biofilm model using a dynamic caries tooth model (CDC reactor) The biofilm growth over the sealed teeth was assessed via colony-forming unit counting metabolic activity assays The enamel surface hardness loss, degree of conversion, shear bond strength (SBS), and cytotoxicity were also investigated Formulations having DMAHDM displayed antibacterial efficiency of 28-35 and 14-40 log inhibition for Streptococcus mutans and Candida albicans, respectively Furthermore, the metabolic activity was reduced on the top of the sealed tooth with the biointeractive sealing materials (p < 05) The degree of conversion values was acceptable The enamel surface hardness loss decreases (36 ± 98%) when in contact with the biointeractive tooth sealing material The SBS of the combined formulation (5% DMAHDM + 20% NACP) was lower than commercial sealant but similar to experimental control The investigated sealing material holds valuable dual antibacterial and antifungal activities associated with a reduced mineral loss against the cariogenic challenge promoted by ECC key pathogens
TL;DR: Wollastonite is a promising filler to improve the biological properties of adhesives and assist in dentin-restoration stability and improved the mechanical behavior of the adhesive without changing the analyzed chemical properties.
TL;DR: Intense and episodic ethanol intake decreased alveolar bone quality in all microstructural parameters analyzed which may be considered a modifying factor of periodontitis, intensifying the already installed disease.
Abstract: BACKGROUND Periodontitis is a multifactorial inflammatory disease of tooth supporting tissues caused by oral biofilms, influenced by environmental and genetic factors, among others. Ethanol consumption has been considered a factor that enhances alveolar bone loss, especially in high doses. The present study aims to investigate the changes promoted by ethanol binge drinking per se or associated with ligature-induced periodontal breakdown on alveolar bone loss. MATERIALS AND METHODS Thirty-two Wistar rats were randomly allocated into four groups: control (C), ethanol (3g/kg/day; 3 days On-4 days Off protocol by gavage for 28 days, EtOH), experimental periodontitis (EP) and experimental periodontitis plus ethanol administration (EP+EtOH). On day 14th, periodontitis was induced by ligatures that were placed around the lower first molars. On day 28th, the animals were euthanized and mandibles were submitted to stereomicroscopy for exposed root area analysis and micro-computed tomography (micro-CT) for the evaluation of alveolar bone loss and microstructural parameters. RESULTS The results revealed that ligature-induced alveolar bone loss is aggravated by ethanol binge drinking compared to controls (1.06 ± 0.10 vs 0.77 ± 0.04; p<0.0001). In addition, binge drinking per se altered the alveolar bone quality and density demonstrating a reduction in trabecular thickness, trabecular number parameter and bone density percentual. Periodontal disorder plus ethanol binge drinking group also demonstrated reduction of the quality of bone measured by trabecular thickness. CONCLUSIONS In conclusion, intense and episodic ethanol intake decreased alveolar bone quality in all microstructural parameters analyzed which may be considered a modifying factor of periodontitis, intensifying the already installed disease.
TL;DR: Non-agglomerated Ta2O5QDs synthesized from an imidazolium ionic liquid provided antibacterial activity to the experimental adhesive resin against biofilm formation of Streptococcus mutans.
Abstract: Purpose To synthesize tantalum oxide quantum dots (Ta2O5QDs) using an imidazolium ionic liquid as a precursor and evaluate the effect of its addition to an experimental adhesive resin on the degree of conversion (DC) and antibacterial activity. Materials and methods Ta2O5QDs was synthesized from the hydrolysis of an imidazolium ionic liquid (1-n-decyl-3-methylimidazolium hexachlorotantalate [DMI.TaCl6]) and evaluated by transmission electron microscopy (TEM). The adhesive was formulated with 66.7 wt% bisphenol A-glycidyl methacrylate (bis-GMA), 33.3 wt% 2-hydroxyethyl methacrylate (HEMA) with a photoinitiator/co-initiator system. In one group, Ta2O5QDS was added to the adhesive at 1 wt% Ta2O5QDs) and one group remained without Ta2O5QDS as control (CTRL). The adhesives were evaluated for DC by Fourier Transform Infrared spectroscopy. Direct contact inhibition assay was used to evaluate the antibacterial activity of the experimental adhesive resins against biofilm formation and planktonic bacteria. Results Ta2O5QDs had a particle size distribution of 1.52 ± 0.73 nm. DC was 50.91 ± 4.94% for CTRL and 55.4 ± 4.58% for Ta2O5QDs (p = 0.310). Ta2O5QDs showed less Streptococcus mutans biofilm formation on adhesive surfaces (p = 0.013). There was no statistically significant difference in terms of antibacterial activity against planktonic bacteria (p = 0.079). Conclusion Non-agglomerated Ta2O5QDs synthesized from an imidazolium ionic liquid provided antibacterial activity to the experimental adhesive resin against biofilm formation of Streptococcus mutans.
TL;DR: Overall, the incorporation of ZnO-NN provided an antibacterial effect against Enterococcus faecalis without a significant detrimental impact on the physical and chemical functionality of the material.
Abstract: This study aimed to evaluate the effect of needle-like zinc oxide nanostructures (ZnO-NN) on the physical, chemical, and antibacterial properties of experimental methacrylate-based dental sealers. ZnO-NN was synthesized and characterized. ZnO-NN was added to a co-monomer blend at 20, 30, and 40 wt.%. One group without ZnO-NN was used as a control. The dental resin sealers were evaluated for their flow, film thickness, water sorption, solubility, radiopacity, degree of conversion (DC), dental-sealer interface characterization via micro-Raman, and antibacterial activity. ZnO-NN presented a mean needle diameter of 40 nm and 16 m2/g of surface area. There was no difference among groups containing ZnO-NN regarding their flow. The ZnO-NN addition significantly increased the film thickness. Water sorption and solubility tests showed no difference among groups. The radiopacity increased, and DC decreased with higher concentrations of ZnO-NN. Micro-Raman suggested that ZnO-NN was in close contact with root canal dentin. Overall, the incorporation of ZnO-NN provided an antibacterial effect against Enterococcus faecalis without a significant detrimental impact on the physical and chemical functionality of the material. The use of ZnO-NN as an inorganic filler is a potential application within dental materials intended for root canal treatment.
TL;DR: Niobium silicate particles could promote the remineralization of dentin hard tissues without compromising the physico-mechanical properties on these materials.
TL;DR: Results showed that CS was able to change the blood oxidative biochemistry in CS and CS+EP groups, decrease GSH activity in the blood, and increase the NO and TBARS concentrations.
Abstract: We aimed to investigate the effects of chronic stress (CS) on experimental periodontitis (EP) in rats. For this, 28 Wistar rats were divided into four groups: control, ligature-induced experimental periodontitis (EP), chronic stress (CS; by physical restraint model) and CS+EP (association of chronic stress and ligature-induced periodontitis). The experimental period lasted 30 days, including exposure to CS every day and ligature was performed on the 15th experimental day. After 30 days, the animals were submitted to the behavioral test of the elevated plus maze (EPM). Next, rats were euthanized for blood and mandible collection in order to evaluate the oxidative biochemistry (by nitric oxide (NO), reduced-glutathione activity (GSH), and thiobarbituric acid reactive substance levels (TBARS)) and alveolar bone characterization (by morphometric, micro-CT, and immunohistochemistry), respectively. The behavioral parameters evaluated in EPM indicated higher anxiogenic activity in the CS and CS+EP, groups, which is a behavioral reflex of CS. The results showed that CS was able to change the blood oxidative biochemistry in CS and CS+EP groups, decrease GSH activity in the blood, and increase the NO and TBARS concentrations. Thus, CS induces oxidative blood imbalance, which can potentialize or generate morphological, structural, and metabolic damages to the alveolar bone.
TL;DR: A strategy to endow antibacterial ability to resin infiltrants, a new and conservative class of material for microinvasive treatments, and the polyhexamethylene guanidine hydrochloride conveys biofilm inhibition to resin infiltration while not adversely affect the critical physical properties of this material is reported.
TL;DR: The formulation of dental sealants containing TAT and α-TCP can be characterized by improved mechanical and antibacterial properties, and shows greater antibacterial activity in comparison to GCTRL.
Abstract: Quaternary ammonium compounds and calcium phosphates have been incorporated into dental materials to enhance their biointeractivity and preventive effects. This study aimed at evaluating the physical and chemical properties and effects against Streptococcus mutans of a dental sealant containing 1,3,5-tri acryloyl hexahydro-1,3,5-triazine (TAT) and α-tricalcium phosphate (α-TCP). A methacrylate-based dental sealant was initially formulated. α-TCP and TAT (Gα-TCPTAT) were added to the experimental sealant at 2 wt.% each. One group was formulated without α-TCP and TAT and used as control (GCTRL). All tested resins were analyzed for polymerization kinetics and degree of conversion (DC %), Knoop hardness (KHN), softening in solvent (∆KHN%), ultimate tensile strength (UTS), the contact angle with water or with α-bromonaphthalene, surface free energy (SFE) and antibacterial activity against Streptococcus mutans in biofilm and in planktonic cells. The polymerization kinetic was different between groups, but without statistical differences in the DC % (p 0.05), but Gα-TCPTAT presented greater UTS compared to GCTRL (p 0.05) or SFE (p > 0.05). Gα-TCPTAT showed greater antibacterial activity in comparison to GCTRL (p < 0.05). The formulation of dental sealants containing TAT and α-TCP can be characterized by improved mechanical and antibacterial properties.
TL;DR: GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging.
Abstract: Purpose The aim of this study was to evaluate the chemomechanical properties, antibacterial activity, and cytotoxicity of an experimental adhesive resin containing halloysite nanotubes (HNT), doped with alkyl trimethyl ammonium bromide (ATAB). Materials and methods A filler of HNT doped with ATAB was obtained (ATAB:HNT) and incorporated (5 wt%) into a resin blend made of bisphenol A glycerolate dimethacrylate, 2-hydroxyethyl methacrylate and a photoinitiator/co-initiator system (GATAB:HNT). The same resin blend without ATAB:HNT was used as control (Ctrl). The ATAB:HNT filler was assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two tested adhesives were evaluated for degree of conversion (DC) in vitro and in situ, softening in alcohol, dentin microtensile bond strength (µTBS), antibacterial activity, and cytotoxicity (n = 5). Results SEM showed that the nanotubes had a characteristic tubular-needle morphology, while the TEM analysis confirmed the presence of ATAB inside the lumens of HNT. The incorporation of ATAB:HNT induced no reduction (p > 0.05) of the DC either in situ or in vitro. No difference was encountered after the softening challenge test (p > 0.05) and no difference was found in µTBS between the two adhesives, both at 24 h (p > 0.05) and after 6 months of storage in distilled water (p > 0.05). However, ATAB:HNT reduced Streptococcus mutans viability (p 0.05). Conclusions GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging. Moreover, the ATAB:HNT filler can provide antibacterial activity to the adhesive resin without affecting pulp cell viability.
TL;DR: It was possible to observe that eugenol could negatively affect the bonding of resin-based restorative materials to dentin, and further evidence is necessary in order to acquire more accurate information about this issue and confirm that the residual presence of Eugenol in dentin compromises the bond strength of resin -based materials.
Abstract: The aim of this study was to determine whether the residual presence of eugenol in coronal dentin may compromise the bond strength of resin-based restorative materials. A search was performed on MEDLINE/Pubmed, Scopus, and by hand search for relevant papers. No restriction was applied for language and publication date. The studies selected for analysis tested specimens with reduced size (micro-shear bond strength (µSBS) and micro-tensile bond strength (µTBS)) of adhesive systems and resin-based restorative materials applied to coronary dentin “contaminated” with eugenol-based materials. The search provided 335 articles, but only 10 studies met the inclusion criteria. The pooled global analysis showed a significant influence of eugenol, as it negatively influenced the bond strength of resin-based restorations (5.79 (3.31–8.28) MPa, p < 0.00001). The subgroup analyses for conventional etch-and-rinse (p = 0.003) and self-etch (p < 0.0004) adhesive systems, as well as for µSBS (p = 0.01) and µTBS (p < 0.0001), showed a negative influence of eugenol on the bond strength. Data were statistically heterogeneous. However, it was possible to observe that eugenol could negatively affect the bonding of resin-based restorative materials to dentin. Further evidence is necessary in order to acquire more accurate information about this issue and confirm that the residual presence of eugenol in dentin compromises the bond strength of resin-based materials.
TL;DR: Reliable bond strength to prosthetic substrates can be achieved with specific universal resin-luting cements and may be an alternative to glass ionomer cements when luting alloy substrates.
Abstract: This study aimed at evaluating the shear bond strength (SBS) of modern self-adhesive resin cements and resin-modified glass ionomer cements applied to different prosthetic substrates. Zirconia, lithium-disilicate glass-ceramic and a noble metal alloy were used as bonding substrates. They were all sand-blasted with alumina, while LD was further etched with 9.6% hydrofluoric acid (10 s). A light-curing resin-modified glass ionomer cement (3M-GIC: Ketac Cem Plus) and a self-curing resin-modified glass ionomer cement (GC-GIC: FujiCEM 2) were compared to self-adhesive resin cements (PAN: Panavia SA Universal) and (3M-RES: Rely X Unicem 2). Ten specimens for each substrate were produced and up to five cylinders of each cement were bonded to each substrate. The shear bond strength (SBS) was evaluated after 24 h or after thermocycling (TC) aging (5000 cycles). The data was statistically analysed by two-way ANOVA and Student–Newman–Keuls test (α = 0.05). Failure modes were analysed through stereoscopic microscopy. The greatest SBS was attained with PAN, whilst 3M-GIC showed the lowest SBS and failed prevalently in adhesive mode. No difference in SBS was observed between GC-GIC and 3M-RES. After TC aging, all cements showed significant drop (p < 0.05) in SBS, but PAN showed the greatest SBS. Reliable bond strength to prosthetic substrates can be achieved with specific universal resin-luting cements and may be an alternative to glass ionomer cements when luting alloy substrates.
TL;DR: LiNbO3 was successfully incorporated in dental adhesives, increasing the radiopacity and their resistance to degradation and encourages new tests to better investigate the antimicrobial action of LiNb O3 through temperature variation.
Abstract: The aim of the present study was to formulate dental adhesives with different concentrations of LiNbO3 and to evaluate their physicochemical and antibacterial properties. A dental adhesive was formulated using methacrylate monomers and photoinitiators and used as a control filler-free group. Subsequently, three experimental adhesives doped with LiNbO3 at different concentrations (1 wt.%, 2 wt.%, and 5 wt.%) were also formulated. All the experimental adhesives were assessed to evaluate the degree of conversion (DC), softening in solvent, immediate and long-term microtensile bond-strength (μ-TBS), radiopacity, ultimate tensile strength, and antibacterial activity. The incorporation of 1 wt.% of LiNbO3 had no negative effect on the DC of the adhesive resin compared to the control group (p > 0.05). We observed a decrease in the percentage of softening in solvent in the group LiNbO3 at 1 wt.% (p 0.05). After six months, the group with 5 wt.% still presented the highest μ-TBS (p 0.05). LiNbO3 was successfully incorporated in dental adhesives, increasing the radiopacity and their resistance to degradation. Although LiNbO3 offered no antibacterial properties, the reliability of LiNbO3 incorporation in the adhesive encourages new tests to better investigate the antimicrobial action of LiNbO3 through temperature variation.
TL;DR: DFT with the Local Density Approximation and norm-conserving pseudopotentials is used to analyze the energetic stability as well the electronic properties when titanium dioxide quantum dots are added to an adhesive resin, suggesting that the ionic liquid is important to stabilize the TiO2QDs/BMI.BF4.
TL;DR: HAp was the calcium phosphatethat most adversely affected the surface roughness and themechanical property of the material, mainly when exposed toan acid medium, and its valued increased after lactic acid storage.
Abstract: Aim: To evaluate the behavior of experimental dental adhesiveswith hydroxyapatite (HAp), alpha-tricalcium phosphate (α-TCP)or octacalcium phosphate (OCP) after storing them in threedifferent media: dry storage, distilled water, or lactic acid.Methods: An experimental adhesive resin was formulated withbisphenol A glycol dimethacrylate, 2-hydroxyethyl methacrylate,and photoiniciator/co-initiator system. HAp (GHAp), α-TCP(Gα-TCP), or OCP (GOCP) were added to the adhesive resin at 2wt.%, and one group remained without calcium phosphates tobe used as a control (GCtrl). The adhesives were evaluated forsurface roughness, scanning electron microscopy (SEM), andultimate tensile strength (UTS) after storing in distilled water(pH=5.8), lactic acid (pH=4) or dry medium. Results: The initialsurface roughness was not different among groups (p>0.05).GHAp showed increased values after immersion in water(p<0.05) or lactic acid (p<0.05). SEM analysis showed a surfacevariation of the filled adhesives, mainly for Gα-TCP and GHAp. GHApshowed the highest UTS in dry medium (p<0.05), and its valuedecreased after lactic acid storage (p<0.05). Conclusions:The findings of this study showed that HAp, OCP, and α-TCPaffected the physical behavior of the experimental adhesiveresins in different ways. HAp was the calcium phosphatethat most adversely affected the surface roughness and themechanical property of the material, mainly when exposed toan acid medium.
TL;DR: Large disparities among state research outputs have been described and must be addressed by research and development policies, but research workforce and general education variables seem to be good predictors.
Abstract: Aim: To explore socioeconomic, educational and research factors associated with dental research productivity at the state level in Brazil. Methods: The authors used the Scopus database to identify dental articles published from 2006 to 2016 associated with Brazilian universities at the state level. Several social, economic, educational and research structure variables were obtained from the census and National Research Council to predict the rate of articles per 100 thousand inhabitants among the 27 Brazilian states. Rates were fitted in linear weighted least-squared regression with stepwise technique. Twenty-two variables were grouped in six blocks (social, economic, general education, dental education, research workforce and structure). Results: A total of 21189 articles were published, and the state of Sao Paulo accounted for 46%, followed by Rio Grande do Sul with 9.4%; four states did not publish any articles. There were an average (± standard deviation) of 2.6 (±1.98) published articles per 100 researchers and 13.4 (±9.6) articles per 100 thousand inhabitants. Research structure and workforce explained 92.4% and 87.2% of state variability, respectively, while the final model explained 94.5%. One extra PhD and one extra undergraduate researcher per 100 thousand inhabitants were associated with 11.3 more and 3.5 fewer articles, respectively, while every 10 points (range 0-100) on the Human Development Index (Education Component) was associated with 3.3 more articles. Conclusion: State scientific output has several associated factors, but research workforce and general education variables seem to be good predictors. Large disparities among state research outputs have been described and must be addressed by research and development policies.
TL;DR: This new strategy fits with ongoing dental caries preventive and minimally invasive approaches by preventing biofilm growth over-restored carious root lesions and improving the lifespan of dental restorations.
Abstract: Resin composites are the material of choice for dental restorative treatment in oral health care. However, the inherent composition of this class of material commonly results in microbial adherence and colonization, which carries the potential risk of recurrent carious lesions around dental restorations. The high risk of dental composites failure complicates the treatment of root caries, defined as the onset of tooth decay over the prone root surface of a tooth. The restorative treatment of root caries among high caries risk individuals, especially for senior patients, is a challenging, painful, and costly. This study assesses the antibiofilm performance of a surface contact killing antibacterial dental resin composites on the growth of microcosm biofilms using dental plaque sampled from patients with active root carious lesions as an inoculum. The designed formulations contain dimethylaminohexadecyl methacrylate (DMAHDM), a tailored quaternary ammonium monomer with an alkyl chain length of 16, at 3-5 wt.% in a base resin with and without 20 wt.% nanoparticles of amorphous calcium phosphate (NACP). Biofilms were grown on the tested resin composites using a 48 h plaque-derived microcosm biofilm model. Dental plaque collected from active root carious lesions was used as an inoculum to emulate the microbiota present in those lesions. The biofilm growth was assessed via the colony-forming unit (CFU) counts in four culture media, metabolic behavior, lactic acid production, and confocal microscopy. The percentage of reacted double bonds of the formulations was also investigated. The dental resin composites formulated with 3-5 wt.% DMAHDM and 20 wt.% NACP were effective at eradicating surface-attached biofilms from the total microbial load and each relevant cariogenic group: total streptococci, mutans streptococci, and lactobacilli. The metabolic activities and lactic acid production of the plaque-derived microcosm biofilms were reduced by 80-95%, respectively. Fewer viable microorganisms were observed over resin composites containing DMAHDM and NACP. Besides, all the experimental formulations demonstrated an acceptable degree of conversion values. This new strategy fits with ongoing dental caries preventive and minimally invasive approaches by preventing biofilm growth over-restored carious root lesions and improving the lifespan of dental restorations.
TL;DR: Investigating the effects of caffeine on alveolar bone damage induced by an ethanol binge drinking paradigm during adolescence showed that caffeine prevented the periodontal disorder caused by ethanol binge Drinking during adolescence, an effect that was not mediated by adenosine A2A receptor blockade.