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To evaluate the physical properties of enamel submitted to hydrogen peroxide (HP) incorporated with titanium dioxide nanoparticles (NP) co-doped with nitrogen and fluorine and irradiated with violet LED light (LT). Enamel-dentin disks were randomly allocated (T0) into groups, according to HP (HP6, HP15, or HP35) and NP (no NP, 5NP, or 10NP) concentrations, and irradiated or not with LT. A negative control (NC) group was set. After three bleaching sessions (T1, T2, and T3), specimens were stored in saliva for 14 days (T4). Enamel surface microhardness number (KHN), surface roughness (Ra), cross-sectional microhardness (ΔS), energy-dispersive spectroscopy (EDS), scanning electron (SEM), and polarized light (PLM) microscopies were performed. Surface KHN was significantly influenced by NP over time, independently of LT irradiation. At T3 and T4, gels with 5NP and 10NP exhibited no KHN differences compared to NC and baseline values, which were not observed under the absence of NP. NP incorporation did not statistically interfere with the ΔS and Ra. PLM images exhibited surface/subsurface darkening areas suggestive of demineralizing regions. SEM demonstrated some intraprismatic affection in the groups without NP. EDS reported a higher enamel calcium to phosphorus ratio following 10NP gels applications. Gels with NP maintained the enamel surface microhardness levels and seemed to control surface morphology, upholding the mineral content. None of the proposed experimental protocols have negatively influenced the enamel surface roughness and the cross-sectional microhardness.
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OBJECTIVE: The present work demonstrates the optimization of a renilla-based real-time, ultra-bright, non-disruptive, high-throughput bioluminescence assay (HTS) to assess the metabolism of intact Streptococcus mutans biofilms and its utility in screening the antibacterial efficacy of experimental nanofilled dental adhesive resins containing varying concentrations of nitrogen-doped titanium dioxide nanoparticles (N_TiO2). METHODS: Optimization of the assay was achieved by screening real-time bioluminescence changes in intact Streptococcus mutans biofilms imposed by the various experimental biofilm growth parameters investigated (bacterial strain, growth media, sucrose concentration, dilution factor, and inoculum volume). The optimized assay was then used to characterize the antibacterial efficacy of experimental nanofilled dental adhesive resins. The assay's ability to discriminate between bacteriostatic and bactericidal approaches was also investigated. RESULTS: Relative Light Units (RLU) values from the HTS optimization were analyzed by multivariate ANOVA (α = 0.05) and coefficients of variation. An optimized HTS bioluminescence assay was developed displaying RLUs values (brightness) that are much more intense when comparing to other previously reported bioluminescence assays, thereby decreasing the error associated with bioluminescence assays and displaying better utility while investigating the functionalities of antimicrobial nanofilled experimental dental adhesive resins with proven long-term properties. SIGNIFICANCE: The present study is anticipated to positively impact subsequent research on dental materials and oral microbiology because it serves as a valuable screening tool in metabolic-based assays with increased sensitivity and robustness. The assay reported is anticipated to be further optimized to be used as a co-reporter for other Luc based assays.
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OBJECTIVES: The objective of the study is to evaluate the bleaching potential of 6% hydrogen peroxide (6% HP) gels containing NF_TiO2 or Nb2O5 irradiated with a violet LED light and the effects on enamel mineral content and surface morphology. METHODS: Particles were synthesized, and experimental gels were chemically analyzed by preliminary and accelerated stability tests, pH, and HP decomposition rate. Bovine enamel blocks were treated with 6% HP gels containing (n = 10): 5% NF_TiO2, 5% Nb2O5, 2.5% NF_TiO2 + 2.5% Nb2O5 or without particles (6% HP), irradiated or not with LED, and the control was treated with 35% HP. Color (∆E00) and whitening index (∆WID) variations, surface microhardness (SH), average roughness (∆Ra), Ca-P concentration (EDS), and enamel morphology (SEM) were assessed. Bleaching was performed in 3 sessions of 30 min and 7-day intervals. Data were submitted to two- (pH, decomposition rate, ∆E00, and ∆WID) or three-way ANOVA and Bonferroni (SH), Kruskal-Wallis (∆Ra), and Dunnet tests (α = 0.05). RESULTS: No changes in the gel's color, odor, or translucency were observed. The pH (6 to 6.5) remained stable over time, and light irradiation boosted the HP decomposition rate. NF_TiO2 and Nb2O5-containing gels displayed higher ∆E00 and ΔWID when light-irradiated (p < 0.05). Nb2O5 and Nb2O5 + NF_TiO2 decreased enamel SH (p < 0.05), but no SH changes were found among groups (p > 0.05). No differences among groups were noted in ∆Ra, Ca-P content, and enamel morphology after treatments (p > 0.05). CONCLUSION: Experimental light-irradiated 6% HP gels containing NF_TiO2 or Nb2O5 were chemically stable and exhibited bleaching potential comparable with 35% HP. CLINICAL RELEVANCE: Low-concentrated HP gels containing NF_TiO2 or Nb2O5 and light-irradiated stand as a possible alternative to in-office bleaching.
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Clareadores Dentários , Clareamento Dental , Animais , Bovinos , Clareadores Dentários/farmacologia , Peróxido de Hidrogênio/farmacologia , Ácido Hipocloroso , GéisRESUMO
This study developed an experimental flowable composite incorporated with niobium pentoxide (Nb2O5) combined or not with titanium dioxide co-doped with fluorine and nitrogen (NF_TiO2) and evaluated the mechanical and antibacterial properties. The experimental flowable composite (TEGDMA + BisGMA 1:1 + 60%wt - inorganic filler - borosilicate 0.7 µm) was formulated according to the type and concentration of Nb2O5 and NF_TiO2 (0.5, 1, 1.5 and 2 wt%) or NF_TiO2 + Nb2O5 (0.25, 0.5, 0.75 and 1 wt% - 1:1). The control groups were formed by the experimental composite without the incorporation of Nb2O5 and/or NF_TiO2 (GC-E) and by a commercial flowable composite (GC). The characterization of the surface of the composite and its particles was carried out using scanning electron microscopy (SEM) and energy dispersive x-rays (EDX). Specimens were manufactured and subjected to mechanical tests of flexural strength (FS) (n = 12), flexural modulus (FM) (n = 12), roughness (Ra) (n = 10), microhardness (n = 10), and contact angle (n = 10); and, to evaluate the antibacterial activity, they were submitted to tests of biofilm formation against S. mutans (CFU/mL) (n = 5), biofilm biomass by dry weight (n = 5) and confocal laser microscopy (%LIVE/DEAD) (n = 5). Data were submitted to one-way ANOVA and Tukey's post-hoc and, those that were not homoscedastic, but with normality, were submitted to Welch's ANOVA and Games-Howell's post-hoc. Dunnet's test was used to compare the controls with the other experimental groups (α = 5). The Nb2O5 particles had an average size of 32.4 µm and the nanoparticles (NPs) of NF_TiO2, 10 nm. EDX analysis identified isolated peaks of N, F, Ti, and Nb confirming the presence of these particles in the resin matrix. The 1.5% NF_TiO2 group had a higher FS and FM than the controls (p < 0.05). GC showed higher microhardness between groups (p < 0.05). There was no difference between the experimental groups regarding contact angle and roughness (p > 0.05), except for GC, which had the highest Ra values and the lowest contact angle between groups (p < 0.05). Composites containing 0.5%, 1%, 1.5%, and 2% Nb2O5, 1%, 1.5%, and 2% NF_TiO2 and 2% Nb2O5 + NF_TiO2 showed lower biofilm formation (p < 0.05), lower total biofilm biomass (p < 0.05), and a higher percentage of dead cells (44%, 52%, 52%, 79%, 42% 43%, 62%, 65%, respectively) than GC and GC-E (5% and 1%, respectively). It is concluded that the incorporation of 1.5% NF_TiO2 promoted a greater FS and FM among the experimental composites and that the addition of Nb2O5 particles (0.5%, 1%, 1.5%, and 2%), NF_TiO2 (1%, 1.5% and 2%) and the combination Nb2O5 + NF_TiO2 (2%) showed significant antibacterial effects.
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Nanopartículas , Nióbio , Teste de Materiais , Resinas Compostas , Antibacterianos/farmacologia , Propriedades de SuperfícieRESUMO
INTRODUCTION: Tooth whitening procedures are under continuous investigation to improve esthetic outcomes and reduce bleaching sensitivity (BS) precipitating from treatments. During the dental bleaching process it is known that the release of free radicals degrades the organic pigment molecules of the tooth and with this an amount of energy is released. Nonetheless, previous studies have never investigated the temporal correlation between of pH and electric potential (EP) generated in this treatment. OBJECTIVES: Therefore, the objective of the present study was to investigate temporal variations of pH and EP associated with three different commercially available bleaching gels and the correlation levels between parameters of interest to provide relevant information regarding the kinetics of oxidation reactions in dental bleaching procedures. METHODS: The study was divided into 3 groups (n = 9) in function of hydrogen peroxide concentration (either 6%, 15% and 35%). The temporal evolution of pH and EP values were determined using a highly-accurate and previously calibrated pH meter at specific time-points (5, 10, 15 and 30 min). RESULTS: Data obtained were submitted to one-way ANOVA of repeated measures with Bonferroni post-test (α = 0.05). The results of the study showed difference in the factor gel concentration (p < 0,0001), time (p < 0,0001) and interaction (gel/time) (p = 0.002) while throughout the intervals evaluated the groups remained relatively stable and without significant difference in the intragroup variation of pH (p < 0.05) and in EDP only with significant difference in the 5 min interval of the 35% concentration. A 2nd order polynomial relationship test showed high correlation levels. CONCLUSION: It can thus be concluded that there is a negative relationship between EP and pH variation in the different gel concentrations. CLINICAL SIGNIFICANCE: The findings of the present study suggest that bleaching gels of higher concentration may provoke BS that are more intense and durable due to significant electric depolarization of neuronal extensions of pulpal tissues.
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The coronavirus disease 2019 pandemic has imposed unprecedented occupational challenges for healthcare professionals. In dentistry, handheld instruments such as air and electric handpieces, ultrasonic scalers, and air/water syringes are capable of generating aerosols, droplets, and splatter, thereby exposing dental professionals to airborne contaminants such as viruses, bacteria, and fungi. The objective of the present study was to determine the spatial distribution of aerosols by size (0.30 to 20.00 µm) and the efficacy of a novel aerosol containment device (ACD) in a large operatory room with 12 dental chairs. Real-time portable laser aerosol spectrometers were used to measure the size-resolved number concentration of aerosols generated by a collision nebulizer. Results reported demonstrate that aerosol number concentrations significantly decreased as a function of distance with or without the utilization of the ACD. The ACD was able to efficiently decrease (up to 8.56-fold) the number and size distribution of particles in a large dental clinic. The novel device demonstrated higher efficiency for particles shown to contain the highest levels of severe acute respiratory syndrome coronavirus 2 in Chinese hospitals, thereby showing great promise to potentially decrease the spreading of nosocomial pathogens in dental settings.
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The present pilot study had the objective to determine the effects of transcutaneous and transmucosal laser irradiation on arterial blood pressure (ABP), glucose (Glu) triglycerides (Tg), total cholesterol (Ch), high-density level cholesterol (HDL) and low-density cholesterol (LDL) immediately after treatment (T0) and after 30 (T30) and 60 (T60) days. Patients (n = 36) were selected and randomly distributed into 6 groups (n = 6/group; [G1] negative control, [G2] radial artery transcutaneous laser irradiation [G3] radial artery transcutaneous irradiation, [G4] transmucosal sublingual irradiation, [G5] transmucosal intra-nasal irradiation and [G6] extended radial artery transcutaneous irradiation). Blood exams were performed at T0, T30 and T60. Systolic and diastolic pressure results have indicated that patients' pressures ranged from 90 mmHg (P22, T30, G4) to 189 mmHg (P16, T0, G3) and 54 mmHg (P21, T60, G4) to 175 mmHg (P16, T30, G3). Levels of Glu at T30 and T60 varied from 5.53% (G1) to -5.78% (G6) and 1.21 (G2) to -8.69 (G6), respectively. Data was statistically assessed for normality and homogeneity of variances using the F-statistic and Bartlett's tests. Significant differences were determined using One-Way ANOVA and Fischer post hoc tests. Results indicated that treatments investigated can be safely used as an adjunct method to regulate blood pressure, glucose, triglycerides and cholesterol.
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OBJECTIVES: To evaluate the bleaching efficacy of a violet radiation (VR) combined or not with bleaching gels on the color and mineral content of stained teeth. MATERIAL AND METHODS: Enamel/dentin blocks were obtained and stained (n = 50) with coffee, red wine, tobacco smoke, or were left non-stained. The stained or not-stained blocks (n = 10) were distributed into five bleaching groups (n = 10): VR, CP (37 % carbamide peroxide), VR/CP, HP (35 % hydrogen peroxide), and VR/HP. Color (ΔE00, ΔL, Δa, and Δb) and whiteness index (ΔWID) changes were evaluated after staining and after bleaching using a spectrophotometer. Calcium (Ca), phosphorous (P), and Ca/P contents (in wt%) were measured after bleaching using energy-dispersive X-ray spectroscopy (EDS). Data was statistically analyzed (α = 0.05) using two-way ANOVA and Tukey tests (ΔE00, ΔWID, ΔL, Δb, wt%) or Kruskal-Wallis and Dunn tests (Δa). RESULTS: VR alone caused higher colorimetric changes on coffee, tobacco and red wine-stained groups compared to non-stained enamel (p < 0.05). VR/CP exhibited higher colorimetric changes compared to CP in coffee and non-stained groups. The VR/CP, HP and VR/HP groups exhibited no change differences (p > 0.05). No differences were observed for the wt% of Ca, P and Ca/P between the groups. CONCLUSIONS: The violet radiation was more effective in bleaching stained rather than non-stained teeth. VR combined with 37 % carbamide peroxide was as effective as the HP agent. Besides, no adverse effects could be observed in the enamel mineral content, regardless of the bleaching protocol tested, according to the EDS semi-quantitative analysis.
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Fotoquimioterapia , Clareadores Dentários , Clareamento Dental , Animais , Bovinos , Cor , Esmalte Dentário , Fotoquimioterapia/métodos , Fármacos FotossensibilizantesRESUMO
Previous reports demonstrated the utility of systemic application of growth hormone (GH) in the treatment of bone defects. Very few studies correlated bone repair efficacy with hepatic and renal side effects promoted by locally-delivered GH. The objectives of this study were to assess the bone repair properties along with hepatic and renal adverse effects promoted by local application of GH in a rat model. Thirty-two rats were randomly divided (4 groups; n = 8/group), as follows: (i) AB (autogenous bone + local application of saline solution [SS]), (ii) AB+ (autogenous bone + SS local application + SS irrigation), (iii) AB/GH+ (autogenous bone + SS local application + GH irrigation) and (iv) AB/GHL+ (autogenous bone + GH local application + GH irrigation). Critical-sized defects (diameter = 5.0 mm) were surgically created by a single operator in the calvaria of rats. Defects were filled with ground autogenous bone. Defects pertaining to AB+ and AB/GH+ received a mixture of autogenous bone and a SS-saturated (0.02 mL) collagen sponge covered with bovine cortical membrane. Defects in group AB/GHL+, were filled with the same biomaterials saturated with GH (0.02 mL). SS (0.1 mL) or GH (0.1 mL, equivalent to 0.4 IU) were applied locally on alternate days (8 weeks) in animals in groups AB, AB+ and AB/GH+ or AB/GHL+, respectively. Bone repair properties was determined in hematoxylin/eosin-stained slices using traditional histologic and histomorphometric techniques along with optical microscopy and digital image analysis. Statistical differences among groups was determined using Kruskal-Wallis and Tukey post hoc tests (α = 0.05). Histology results indicated that AB and AB+ displayed greater presence of autogenous bone as compared to AB/GH+ and AB/GHL+. Histomorphometric results indicated significantly higher osteoid matrix formation in AB and AB+ when compared to AB/GHL+ (p = 0.009). Kidneys and livers were found to have their glomeruli preserved in AB and AB+. Strong glomeruli necrosis and large areas of protein deposition were found in AB/GH+. Abnormal small-sized glomeruli were found in AB/GHL+. The utilization of autogenous bone graft associated with local application and irrigation with GH was shown to not improve the bone repair in calvarial critical-sized defects in a rat model.
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Dental adhesives hydrolyze in the mouth. This study investigated the water sorption (SOR), solubility (SOL) and cytotoxicity (CYTO) of experimental adhesives containing nitrogen-doped titanium dioxide nanoparticles (N_TiO2). Specimens (n = 15/group [SOR, SOL]; n = 10/group [CYTO]) of unaltered Clearfil SE Protect (CSP), OptiBond Solo Plus (OSP), Adper Scotchbond (ASB) and experimental adhesives (OSP + 25% or 30% of N_TiO2) were fabricated, desiccated (37 °C) and tested for SOR and SOL according to ISO Specification 4049 (2009). CYTO specimens were UV-sterilized (8 J/cm2) and monomer extracted in growth medium (1, 3 or 7 days). Human pulp cells were isolated and seeded (0.5 × 104) for MTT assay. SOR and SOL data was analyzed using GLM and SNK (α = 0.05) and CYTO data was analyzed with Kruskal-Wallis and SNK tests (α = 0.05). SOR and SOL values ranged from 25.80 µg/mm3 (30% N_TiO2) to 28.01 µg/mm3 (OSP) and 23.88 µg/mm3 (30% N_TiO2) to 25.39 µg/mm3 (25% N_TiO2). CYTO results indicated that pulp cells exposed to experimental materials displayed comparable viabilities (p > 0.05) to those of OSP. Experimental materials displayed comparable SOR, SOL and CYTO values (p > 0.05) when compared to unaltered materials. N_TiO2 incorporation have not adversely impacted SOR, SOL and CYTO properties of unaltered adhesives.
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Antibacterianos/química , Antibacterianos/toxicidade , Nanoestruturas/química , Resinas Sintéticas/química , Resinas Sintéticas/toxicidade , Adesividade , Sobrevivência Celular/efeitos dos fármacos , Polpa Dentária/citologia , Humanos , Solubilidade , Água/químicaRESUMO
Nanotechnology can improve the performance of dental polymers. The objective of this study was to modify the surfaces of nanoparticles with silanes and proteins, characterize nanoparticles' agglomeration levels and interfaces between nanoparticles and the polymeric matrix. Undoped (n-TiO2), nitrogen-doped (N_TiO2) and nitrogen-fluorine co-doped titanium dioxide nanoparticles (NF_TiO2) were synthesized and subjected to surface modification procedures in preparation for Small-Angle X-Ray Scattering (SAXS) and Small-Angle Neutron Scattering (SANS) characterizations. Experimental adhesives were manually synthesized by incorporating 20% (v/v) of n-TiO2, N_TiO2 or NF_TiO2 (as-synthesized or surface-modified) into OptiBond Solo Plus (OPTB). Specimens (n = 15/group; d = 6.0 mm, t = 0.5 mm) of OPTB and experimental adhesives were characterized using Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), 2-D ToF-SIMS chemical imaging and SANS. SAXS results indicated that surface-modified nanoparticles displayed higher scattering intensities in a particle-size dependent manner. ToF-SIMS results demonstrated that nanoparticles' incorporation did not adversely impact the parental polymer. 2-D ToF-SIMS chemical imaging demonstrated the distribution of Ti+ and confirmed nitrogen-doping levels. SANS results confirmed nanoparticles' functionalization and revealed the interfaces between nanoparticles and the polymer matrix. Metaloxide nanoparticles were successfully fabricated, incorporated and covalently functionalized in a commercial dental adhesive resin, thereby supporting the utilization of nanotechnology in dentistry.
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AIM: This in vitro study assessed the effects of in-office bleaching with gels (35% hydrogen peroxide [HP] or 37% cabamide peroxide [CP]) and two activation sources (violet radiation [LED] or nonthermal atmospheric plasma [NTAP]) on the mineral content of bovine enamel. MATERIAL AND METHODS: Dental blocks (nâ¯=â¯90) were assessed for initial microhardness before random distribution into nine groups: LED, LEDâ¯+â¯HP, LEDâ¯+â¯CP, NTAP, NTAPâ¯+â¯HP, NTAPâ¯+â¯CP, HP, CP and control (without treatment). Specimens were subjected to bleaching (2 clinical sessions, 7 days apart) using LED [20x/session, 1-min/each, 30â¯s apart] or NTAP [1x/session, 10â¯min]. µRaman determined contents of phosphate (PO43) and carbonate (CO32). Micro-energy dispersive X-ray fluorescence (µEDXRF) and spectrophotometry of enamel microbiopsy evaluated the calcium to phosphorous ratios (Ca/P). Two-way ANOVA and Tukey tests analyzed µRAMAN and µEDXRF results. Spectrophotometry results were analyzed using Kruskal-Wallis and Dunn tests. Pearson correlation tested µEDXRF and spectrophotometry results (αâ¯=â¯5%). RESULTS: NTAP and NTAPâ¯+â¯HP exhibited greater PO43- content than LED, LEDâ¯+â¯HP and control (pâ¯<â¯0.05). No statistical differences were detected between CO32- among groups. While µEDXRF evaluation demonstrated that NTAP and LED did not alter Ca/P ratio of enamel (pâ¯>â¯0.05), spectrophotometry showed that Ca/P reduced for LEDâ¯+â¯HP (pâ¯<â¯0.05). No correlation was found between µEDXRF and enamel microbiopsy spectrophotometry (pâ¯>â¯0.05). CONCLUSIONS: Activation sources did not adversely impact enamel's phosphate and carbonate concentrations after specimens' exposure to bleaching gels (either HP or CP). Visible light radiation emitted by a LED source was shown to adversely impact specimens' Ca/P ratios when treated with HP-containing bleaching gels.
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Fotoquimioterapia , Clareadores Dentários , Clareamento Dental , Animais , Bovinos , Esmalte Dentário , Minerais , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes , Clareadores Dentários/farmacologiaRESUMO
Novel biomaterials capable of accelerating the healing process of skeletal tissues are urgently needed in dentistry. The present in vivo study assessed the osteoconductive and osteoinductive properties of experimental biphasic bioceramics (HA-TCP) modified or not by a nacre extract (marine organic extract, MOE) in a sheep model. Fabrication of MOE involved mixing ground nacre (0.05 g, particle sizes < 0.1 mm) with glacial ethanoic acid (5 mL, pH 7) for 72 hours using external magnetic stirring (25°C). Nonreactive carriers (sterile polythene tubes; 3/animal, radius: 2.5 mm, length: 10.0 mm) pertaining to the control (empty) or experimental groups (HA-TCP or MOE-modified HA-TCP) were implanted intramuscularly into the abdominal segment of the torso in sheep (n = 8, age: 2 years, weight: 45 kg). Euthanization of animals was performed at 3 and 6 months after surgery. Tissues harvested were subjected to macroscopic and radiographic assessments. Specimens were then stained for histological analysis. Both control and experimental animals were capable of inducing the neoformation of fibrous connective tissue at both time points where superior amounts of tissue formation and mineralization were detected for experimental groups (unaltered (at 3 and 6 mos) and MOE-modified HA-TCP (at 3 mos)). Histological results, however, revealed that mature bone formation was only observed for specimens fabricated with MOE-modified HA-TCP in a time-dependent manner. The present study has successfully demonstrated the in vivo utility of experimental biphasic bioceramics modified by MOE in an ectopic grafting sheep model. Promising osteoconductive and osteoinductive properties must be further developed and confirmed by subsequent research.
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Materiais Biocompatíveis , Regeneração Óssea/efeitos dos fármacos , Nácar , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Cerâmica/química , Feminino , Hidroxiapatitas/química , Nácar/química , Nácar/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Projetos Piloto , OvinosRESUMO
OBJECTIVE: The present work shows the optimization of a high-throughput bioluminescence assay to assess the metabolism of intact Streptococcus mutans biofilms and its utility as a screening method for nanofilled antibacterial dental materials. METHODS: The assay was optimized by monitoring changes in bioluminescence mediated by variation of the experimental parameters investigated (growth media and sucrose concentration, inoculum:D-Luciferin ratio, dilution factor, inoculum volume, luminescence wavelength, replicate and luciferase metabolic activity). Confocal microscopy was then used to demonstrate the impact of biofilm growth conditions on the 3-D distribution of extracellular polymeric substance (EPS) within Streptococcus mutans biofilms and its implications as confounding factors in high-throughput studies (HTS). RESULTS: Relative Luminescence Unit (RLU) values from the HTS optimization were analyzed by multivariate ANOVA (α = 0.05) and coefficients of variation, whereas data from 3-D structural parameters and RLU values of biofilms grown on experimental antibacterial dental adhesive resins were analyzed using General Linear Models and Student-Newman-Keuls post hoc tests (α = 0.05). Confocal microscopy demonstrated that biofilm growth conditions significantly influenced the quantity and distribution of EPS within the 3-D structures of the biofilms. An optimized HTS bioluminescence assay was developed and its applicability as a screening method in dentistry was demonstrated using nanofilled experimental antibacterial dental adhesive resins. SIGNIFICANCE: The present study is anticipated to positively impact the direction of future biofilm research in dentistry, because it offers fundamental information for the design of metabolic-based assays, increases the current levels of standardization and reproducibility while offering a tool to decrease intra-study variability.
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Cimentos Dentários , Streptococcus mutans , Antibacterianos , Biofilmes , Matriz Extracelular de Substâncias Poliméricas , Humanos , Reprodutibilidade dos TestesRESUMO
The objective of this systematic review was to compare the conical internal connection (IC) with the external hexagonal connection (EH) on the occurrence of marginal bone loss (ΔMBL). Different databases were used to carry out the selection of the elected studies. The studies were judged according to the risk of bias as "high", "low" and "unclear" risk. For the meta-analysis we included only studies that could extract the data of ΔMBL, survival rate (SR) and probing depth (PD). No statistically significant differences were found for ΔMBL data at one, three- and five-year survival rates between implant connections (p <0.05), however statistically significant differences were found for PD between EH and IC implants (1-year follow-up) -0.53 [95%CI -0.82 to -0.24, p = 0.0004]. This present systematic review demonstrated that there are no significant differences between IC and EH implants for both ΔMBL and SR at 1, 3 e 5 years after functional loading, although better PD values were observed for implants pertaining to the IC connections. Considering the high heterogeneity, more well-delineated, randomized clinical trials should be conducted.
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Perda do Osso Alveolar/etiologia , Dente Suporte/efeitos adversos , Projeto do Implante Dentário-Pivô/efeitos adversos , Implantes Dentários/efeitos adversos , Humanos , Valores de Referência , Medição de Risco , Fatores de Risco , Fatores de TempoRESUMO
Gingivitis is still considered a major risk factor for the occurrence and progression of periodontal disease. The aim of the present study was to compare the long-term (1, 12, and 18 weeks) antiplaque and antigingivitis efficacies of two commercially available toothpastes, Colgate Total® (CT) and BlueM® (BM), against attached supragingival dental plaque and gingival inflammation in an experimental gingivitis model. A parallel double-blinded randomized clinical trial including 39 dental students who refrained from all plaque control methods (manual or chemical) for 7 days was conducted. After the establishment of clinical gingivitis, participants were randomized into two experimental groups (CT and BM). Plaque index (PI) and gingival index (GI) were then calculated according to Turesky's modified Quigley and Hein index. Participants were assessed in four time periods (preclinical trial phase (W -1), gingivitis phase (W0), one week (W1), twelve weeks (W12), and eighteen weeks (W18)). Participants' stimulated saliva was collected and cultured (either aerobically or anaerobically, 37°C, 48 hours) in each time period (W -1, W0, W1, W12, and W18) for the count of viable colonies. Obtained data were analyzed using 2-way ANOVA and Tukey's test (α = 0.05). No significant differences were found (p > 0.05) between experimental groups at W -1. Significant differences between groups were observed at W0 (p < 0.05) for the parameter time period, but not for the interaction between parameters (time period ∗ toothpastes). Lower bacterial counts were observed in both groups after one week of toothbrushing; however, no significant differences were found between investigated dentifrices. Intra- and intergroup comparisons revealed that significant differences were not found (p > 0.05) between dentifrices at W1, W12, and W18 for both GI and PI. The present study demonstrated that toothpastes containing active oxygen and lactoferrin (BM) have comparable antiplaque and antigingivitis efficacies with triclosan-containing toothpastes (CT).
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Abstract The objective of this systematic review was to compare the conical internal connection (IC) with the external hexagonal connection (EH) on the occurrence of marginal bone loss (ΔMBL). Different databases were used to carry out the selection of the elected studies. The studies were judged according to the risk of bias as "high", "low" and "unclear" risk. For the meta-analysis we included only studies that could extract the data of ΔMBL, survival rate (SR) and probing depth (PD). No statistically significant differences were found for ΔMBL data at one, three- and five-year survival rates between implant connections (p <0.05), however statistically significant differences were found for PD between EH and IC implants (1-year follow-up) -0.53 [95%CI -0.82 to -0.24, p = 0.0004]. This present systematic review demonstrated that there are no significant differences between IC and EH implants for both ΔMBL and SR at 1, 3 e 5 years after functional loading, although better PD values were observed for implants pertaining to the IC connections. Considering the high heterogeneity, more well-delineated, randomized clinical trials should be conducted.
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Humanos , Implantes Dentários/efeitos adversos , Perda do Osso Alveolar/etiologia , Dente Suporte/efeitos adversos , Projeto do Implante Dentário-Pivô/efeitos adversos , Valores de Referência , Fatores de Tempo , Fatores de Risco , Medição de RiscoRESUMO
The development of dental adhesive resins with long-lasting antibacterial properties is a possible solution to overcome the problem of secondary caries in modern adhesive dentistry. OBJECTIVES: (i) Synthesis and characterization of nitrogen-doped titanium dioxide nanoparticles (N_TiO2), (ii) topographical, compositional and wettability characterization of thin-films (unaltered and experimental) and, (iii) antibacterial efficacy of N_TiO2-containing dental adhesives against Streptococcus mutans biofilms. MATERIALS AND METHODS: Nanoparticles were synthesized and characterized using different techniques. Specimens (diameterâ¯=â¯12â¯mm, thicknessâ¯â â¯15⯵m) of OptiBond Solo Plus (Kerr Corp., USA) and experimental adhesives [50, 67 and 80% (v/v)] were fabricated, photopolymerized (1000â¯mW/cm2, 1â¯min) and UV-sterilized (254â¯nm, 800,000⯵J/cm2) for microscopy, spectroscopy, wettability and antibacterial testing. Wettability was assessed with a contact angle goniometer by dispensing water droplets (2⯵L) onto four random locations of each specimen (16 drops/group). Drop profiles were recorded (1â¯min, 25â¯frames/s, 37⯰C) and contact angles were calculated at timeâ¯=â¯0â¯s (θINITIAL) and timeâ¯=â¯59â¯s (θFINAL). Antibacterial testing was performed by growing S. mutans (UA159-ldh, JM10) biofilms for either 3 or 24â¯h (anaerobic conditions, 37⯰C) with or without continuous light irradiation (410⯱â¯10â¯nm, 3â¯hâ¯=â¯38.75â¯J/cm2, 24â¯hâ¯=â¯310.07â¯J/cm2) against the surfaces of sterile specimens. RESULTS: N_TiO2 was successfully prepared using solvothermal methods. Doped-nanoparticles displayed higher light absorption levels when compared to undoped titania. Experimental adhesives demonstrated superior antibacterial efficacy in dark conditions. CONCLUSIONS: The findings presented herein suggest that N_TiO2 is a feasible antibacterial agent against cariogenic biofilms.
Assuntos
Antibacterianos , Biofilmes/efeitos dos fármacos , Cimentos Dentários , Nanopartículas/química , Nitrogênio , Streptococcus mutans/fisiologia , Titânio , Antibacterianos/química , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Cimentos Dentários/química , Cimentos Dentários/farmacologia , Nitrogênio/química , Nitrogênio/farmacologia , Titânio/química , Titânio/farmacologiaRESUMO
BACKGROUND: Novel multifunctional biomaterials were recently designed to allow for an optimized tissue regeneration process. PURPOSE: To comprehensively assess (photographic, radiographic and histological) the in vivo functionality of demineralized bovine bone matrix (DBM) associated with an experimental marine organic extract (MOE) from nacre in a sheep ectopic grafting model. MATERIALS AND METHODS: Synthesis of MOE was based on mixing powdered nacre (0.05 g, particles average size <0.1 mm) with acetic acid (5 mL, pH 7) under constant stirring for 72 hours (25 °C). Polyethylene tubes (3/animal, n = 4, diameter: 5.0 mm × length: 10.0 mm) from the control (empty) or experimental groups (DBM or DBM + MOE) were then intramuscularly implanted into the lumbar regions of sheep (n = 8, 2-years old, ≈45 kg). Animals were euthanized at 3 and 6 months to allow for the collection of tissue samples. Tissue samples were fixed in formalin 10% (buffered, 7 days) in preparation for photographic, radiographic and histological assessments. Acquired images were then analyzed using digital image analysis software to quantify the amount of neoformed tissues, whereas radiographic and histological analyses were performed to determine radiopacity and classification of tissues deposited inside of the tubes. RESULTS: Photographic and radiographic analyses have shown that both pure (unaltered) and MOE-modified DBM were capable of depositing neoformed tissues (at 3 and 6 months), where higher levels of deposition and radiopacity were observed on groups treated with experimental materials. Histological results, however, demonstrated that tissues formed from both unaltered and MOE-modified DBM were only fibrous connective in origin. CONCLUSIONS: As an ectopic grafting in sheep, the experimental organo-biomaterial association applied did not reveal any osteoinductive property but led to a fibrous tissue repair only.
RESUMO
OBJECTIVE: A non-destructive and real-time bioluminescence (BL) assay was used to determine the utility of antimicrobial photodynamic therapy (aPDT) treatments mediated by methylene blue (MB) and laser irradiation (LI) against intact biofilms that are capable of producing caries (cariogenic). The efficacy of antibacterial photodynamic treatments has been currently determined by using either viable colony counts (VCC) or metabolic assays (Alamar Blue) that were demonstrated to have critical limitations when used on microcolony-forming bacteria such as Streptococcus mutans. MATERIALS AND METHODS: Resin composite specimens were fabricated, wet-polished, ultraviolet-sterilized, and stored in water (72 h). S. mutans (strain JM10) biofilms were grown [24 h; 0.65 × THY with 0.1% (w/v) sucrose] on the surfaces of sterile specimens. Antibacterial treatments were performed by using MB (0.0005% and 0.001%) with or without LI (660 ± 10 nm, 6 J/cm2). Specimens treated with chlorhexidine gluconate served as the negative control group. The efficacy of aPDT treatments was determined in terms of BL for intact biofilms and VCC for sonicated bacteria. RESULTS: BL results were corrected by using the Greenhouse-Geisser method and were analyzed with repeated-measures analysis of variance and post hoc Bonferroni test (α = 0.05). VCC results were analyzed by using Kruskal-Wallis and Dunn's multiple-comparisons post hoc tests (α = 0.05). Our findings demonstrated that experimental treatments significantly decreased the viability of S. mutans biofilms (p < 0.05). Moderate reductions in cellular viability were observed on biofilms subjected to aPDT treatments. CONCLUSIONS: This study demonstrated that aPDT has promising potential to be used as an additional method to control oral cariogenic biofilms.