Colchicine reduces the activation of NLRP3 inflammasome in COVID-19 patients.

OBJECTIVE: To evaluate whether colchicine treatment was associated with the inhibition of NLRP3 inflammasome activation in patients with COVID-19. METHODS: We present a post hoc analysis from a double-blinded placebo-controlled randomized clinical trial (RCT) on the effect of colchicine for the treatment of COVID-19. Serum levels of NOD-like receptor protein 3 (NLRP3) inflammasome products-active caspase-1 (Casp1p20), IL-1ß, and IL-18-were assessed at enrollment and after 48-72 h of treatment in patients receiving standard-of-care (SOC) plus placebo vs. those receiving SOC plus colchicine. The colchicine regimen was 0.5 mg tid for 5 days, followed by 0.5 mg bid for another 5 days. RESULTS: Thirty-six patients received SOC plus colchicine, and thirty-six received SOC plus placebo. Colchicine reduced the need for supplemental oxygen and the length of hospitalization. On Days 2-3, colchicine lowered the serum levels of Casp1p20 and IL-18, but not IL-1ß. CONCLUSION: Treatment with colchicine inhibited the activation of the NLRP3 inflammasome, an event triggering the 'cytokine storm' in COVID-19. TRIAL REGISTRATION NUMBERS: RBR-8jyhxh.

In vitro characterization of Trichophyton rubrum and T. mentagrophytes biofilms.

Dermatophytes are fungi responsible for a disease known as dermatophytosis. Biofilms are sessile microbial communities surrounded by extracellular polymeric substances (EPS) with increased resistance to antimicrobial agents and host defenses. This paper describes, for the first time, the characteristics of Trichophyton rubrum and T. mentagrophytes biofilms. Biofilm formation was analyzed by light microscopy, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) as well as by staining with crystal violet and safranin. Metabolic activity was determined using the XTT reduction assay. Both species were able to form mature biofilms in 72 h. T. rubrum biofilm produced more biomass and EPS and was denser than T. mentagrophytes biofilm. The SEM results demonstrated a coordinated network of hyphae in all directions, embedded within EPS in some areas. Research and characterization of biofilms formed by dermatophytes may contribute to the search of new drugs for the treatment of these mycoses and might inform future revisions with respect to the dose and duration of treatment of currently available antifungals.

Comparison of Blue and Infrared Light Transmission Through Dental Tissues and Restorative Materials.

OBJECTIVES: The depth of cure using blue-light photocuring units (BL) is limited by tooth structure and qualities of the restorative material through which the activating wavelength must pass. Recent developments incorporate an infrared (IR) activated upconversion (UC) fluorescence of a lining agent filled with nanocrystals of NaYF4 and doped with YB+3 and Tm+3 that emit both blue and violet light locally at the interface of the liner and restorative resin. The purpose of this study was to evaluate the BL and 975 nm infrared (IR) light power transmission through dental tissues and restorative materials. METHODS AND MATERIALS: Power transmissions of the IR laser (975 nm) and a monowave blue-only light-curing unit (Bluephase 16i) through dental tissues (enamel, dentin, and enamel/dentin junction, or DEJ), eight (8) various dental resin composites, and eight (8) dental ceramics, each at four thicknesses (1, 2, 3 and 4 mm) were evaluated (n=5) using a thermopile sensor (PM10, Coherent Inc) connected to a laser power meter (Fieldmate, Coherent Inc). Power transmission values of each light source and restorative material were subjected to analysis of variance and Tukey test at a pre-set alpha of 0.05. RESULTS: A linear correlation (r=0.9884) between the supplied current and emitted IR power of the laser diode was found, showing no statistical power reduction with increased distances (collimated beam). For tooth tissues, the highest power transmissions for both light sources were observed using 1.0 mm enamel while the lowest values were found for 2.0 mm dentin and an association of 2.0 mm DEJ and 1.0 mm dentin. The only group where IR demonstrated significantly higher transmission when compared to BL was 1.0 mm enamel. For all resin composites and dental ceramics, increased thickness resulted in a reduction of IR power transmission (except for EverX Posterior fiber-reinforced composite and e.max HT ceramic). IR resulted in higher transmission through all resin composites, except for Tetric EvoCeram White. The highest BL transmission was observed for SDR Flow, at all thicknesses. Higher IR/BL ratios were observed for EverX Posterior, Herculite Ultra, and Lava Ultimate, while the lowest ratio was observed for Tetric EvoCeram White. Reduced translucency shades within the same material resulted in lower power ratio values, especially for BL transmission. Higher IR/BL ratios were observed for e.Max LT, VitaVM7 Base Dentin, and e.max CAD HT, while the lowest values were found for VitaVM7 Enamel and Paradigm C. CONCLUSION: IR power transmission through enamel was higher when compared to blue light, while no difference was observed for dentin. The power transmission of IR was higher than BL for resin composites, except for a high value and low chroma shade. Fiber-reinforced resin composite demonstrated the highest IR/BL power transmission ratio. A greater IR/BL ratio was observed for lower translucency ceramics when compared to high translucency.

Microplate alamarBlue assay for Paracoccidioides susceptibility testing.

CLSI method M27-A3 is not available for use with dimorphic fungi, such as those of the Paracoccidioides genus. In this study, we developed a microdilution method and added the alamarBlue reagent to test the responses of Paracoccidioides brasiliensis and Paracoccidioides lutzii against amphotericin B and itraconazole antifungals. The test proved to be sensitive, practical, and inexpensive and can be used to monitor the activity of low-growth microorganisms and their response to various drugs.

Cryptococcosis: epidemiology, fungal resistance, and new alternatives for treatment.

Cryptococcosis is an important systemic mycosis and the third most prevalent disease in human immunodeficiency virus (HIV)-positive individuals. The incidence of cryptococcosis is high among the 25 million people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. In Cryptococcus neoformans, resistance to azoles may be associated with alterations in the target enzyme encoded by the gene ERG11, lanosterol 14α-demethylase. These alterations are obtained through mutations, or by overexpressing the gene encoding. In addition, C. gattii and C. neoformans present a heteroresistance phenotype, which may be related to increased virulence. Other species beyond C. neoformans and C. gattii, such as C. laurentii, have been diagnosed mainly in patients with immunosuppression. Infections of C. albidus have been isolated in cats and marine mammals. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth, which is also related with increased resistance to antifungal agents. Therefore, there is a great need to search for alternative antifungal agents for these fungi. The search for new molecules is currently occurring from nanoparticle drugs of plant peptide origin. This article presents a brief review of the literature regarding the epidemiology of cryptococcosis, as well as fungal resistance and new alternatives for treatment.

Effect of High-radiant Emittance and Short Curing Time on Polymerization Shrinkage Vectors of Bulk Fill Composites.

PURPOSE: To evaluate the effect of short curing time using a high-radiant emittance light on polymerization shrinkage vectors in different consistency bulk-fill composites (BFRCs) using micro-computed tomography. METHODS AND MATERIALS: Radiopaque zirconia fillers were homogeneously incorporated and functioned as radiopaque tracers into two regular-paste: TBFill (Tetric EvoCeram Bulk Fill) and TPFill (Tetric PowerFill), and two flowable (n=6): TBFlow (Tetric EvoFlow Bulk Fill) and TPFlow (Tetric PowerFlow) resin composites. Class I cavities (4 mm depth × 4 mm length × 4 mm width) were 3D-printed and filled in a single increment: TBFill and TBFlow were light-activated using a Bluephase Style 20i (10 seconds in high-mode); TPFill and TPFlow were light-activated using a Bluephase PowerCure (three seconds). The same adhesive system (Adhese Universal) was used for all groups. Microcomputed tomography scans were obtained before and after light-activation. Filler particle movement was identified by polymerization shrinkage vectors at five depths (from 0-4 mm): top, top-middle, middle, middle-bottom and bottom. RESULTS: TPFlow showed the lowest total vector displacement, followed by TBFlow, TBFill and TPFill, significantly different among each other (p<0.05). Generally, BFRCs showed decreased vector displacement with increased depth, and higher displacement at the top-surface (p<0.05). Qualitative analysis showed a similar pattern of vector magnitude and displacement for groups TBFill and TPFill, with displacement vectors on occlusal (top) surfaces toward the center of the restoration from the top to middle areas, and relatively limited displacement at the bottom. TBFlow and TPFlow showed more displacement on the occlusal (top). CONCLUSIONS: Short curing time with high-radiant emittance on fast-curing BFRCs was shown to be a feasible option in terms of vector displacement. Flowable BFRCs presented lower vector displacement than their regular-viscosity versions.

Effect of Ceramic Conditioners on Surface Morphology, Roughness, Contact Angle, Adhesion, Microstructure, and Composition of CAD/CAM Ceramics.

The objective of this study was to investigate the effect of surface treatments in maximum profile valley depth (Rv), surface roughness (Sa), contact angle (Ca), shear bond strength (SBS) of a light-cured resin cement, microstructure, and composition of two CAD/CAM ceramics: Cerec Blocs/Dentsply Sirona (feldspathic - FEL) and Empress CAD/Ivoclar Vivadent (leucite-reinforced - LEU). The ceramic specimens were submitted to six surface treatments: (1) 5% hydrofluoric acid (HF) - 20 seconds; (2) 5% HF - 60 seconds; (3) 10% HF - 20 seconds; (4) 10% HF - 60 seconds; (5) self-etching ceramic primer (MEP) - 20 seconds; and (6) MEP - 60 seconds. Specimens treated with HF received silane application for 1 minute. Rv and Sa were evaluated in a confocal laser microscope (n=10) and the Ca in a goniometer (n=6). For the SBS test, two resin cement cylinders were bonded to each specimen, one tested after 24 hours in distilled water storage (37°C) and the other after one year (n=10). The microstructures and compositions were analyzed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n=4). Rv, Sa, and Ca data were analyzed by two-way ANOVA, and the SBS data by three-way ANOVA, all followed by post-hoc Tukey's test (α=0.05). Results: Surface treatments with HF always produced higher Rv and Sa, and lower Ca than MEP 60s for both ceramics. After 1-year water storage, FEL ceramic treated with MEP for 60 seconds produced higher SBS values than HF treatments, whereas for LEU ceramic there were no differences among treatments. Application of MEP for 20 or 60 seconds produced no difference in Rv, Sa, Ca, and SBS for both ceramics. Surface treatments produced considerable differences in ceramic topography, but subtle ones in composition, for both ceramics. Conclusions: The results indicated that for FEL ceramic, MEP application for 60 seconds yielded higher SBS compared with HF etching, while for LEU ceramic the surface treatments did not influence the SBS results.

No association between chronic cerebrospinal venous insufficiency and pediatric-onset multiple sclerosis.

OBJECTIVE: Chronic cerebrospinal venous insufficiency (CCSVI) was hypothesized to play a causative role in multiple sclerosis (MS). The assessment of pediatric-onset MS (POMS) may provide a unique window of opportunity to study hypothesized risk factors in close temporal association with the onset of the disease. METHODS: Internal jugular veins, vertebral veins and intracranial veins were evaluated with extracranial and intracranial ultrasound in 15 POMS and 16 healthy controls. Assessor's blinding was maintained during the study. We considered subjects positive to CCSVI when at least two criteria were fulfilled. RESULTS: CCSVI frequency was comparable between POMS and controls (p > 0.05). Clinical features were not significantly different between CCSVI-positive and CCSVI-negative patients. CONCLUSIONS: Our findings add to previous data pointing against a causative role of CCSVI in MS.

Adhesion of Histoplasma capsulatum to pneumocytes and biofilm formation on an abiotic surface.

The pathogenic fungus, Histoplasma capsulatum, causes the respiratory and systemic disease 'histoplasmosis'. This disease is primarily acquired via inhalation of aerosolized microconidia or hyphal fragments of H. capsulatum. Evolution of this respiratory disease depends on the ability of H. capsulatum yeasts to survive and replicate within alveolar macrophages. It is known that adhesion to host cells is the first step in colonization and biofilm formation. Some microorganisms become attached to biological and non-biological surfaces due to the formation of biofilms. Based on the importance of biofilms and their persistence on host tissues and cell surfaces, the present study was designed to investigate biofilm formation by H. capsulatum yeasts, as well as their ability to adhere to pneumocyte cells. H. capsulatum biofilm assays were performed in vitro using two different clinical strains of the fungus and biofilms were characterized using scanning electron microscopy. The biofilms were measured using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay. The results showed that both the H. capsulatum strains tested were very efficient at adhering to host cells and forming biofilm. Therefore, this is a possible survival strategy adopted by this fungus.

Effect of temperature on the degree of conversion and working time of dual-cured resin cements exposed to different curing conditions.

OBJECTIVES: This study evaluated the degree of conversion (DC) and working time (WT) of two commercial, dual-cured resin cements polymerized at varying temperatures and under different curing-light accessible conditions, using Fourier transformed infrared analysis (FTIR). MATERIALS AND METHODS: Calibra (Cal; Dentsply Caulk) and Variolink II (Ivoclar Vivadent) were tested at 25°C or preheated to 37°C or 50°C and applied to a similar-temperature surface of a horizontal attenuated-total-reflectance unit (ATR) attached to an infrared spectrometer. The products were polymerized using one of four conditions: direct light exposure only (600 mW/cm(2)) through a glass slide or through a 1.5- or 3.0-mm-thick ceramic disc (A2 shade, IPS e.max, Ivoclar Vivadent) or allowed to self-cure in the absence of light curing. FTIR spectra were recorded for 20 min (1 spectrum/s, 16 scans/spectrum, resolution 4 cm(-1)) immediately after application to the ATR. DC was calculated using standard techniques of observing changes in aliphatic-to-aromatic peak ratios precuring and 20-min postcuring as well as during each 1-second interval. Time-based monomer conversion analysis was used to determine WT at each temperature. DC and WT data (n=6) were analyzed by two-way analysis of variance and Tukey post hoc test (p=0.05). RESULTS: Higher temperatures increased DC regardless of curing mode and product. For Calibra, only the 3-mm-thick ceramic group showed lower DC than the other groups at 25°C (p=0.01830), while no significant difference was observed among groups at 37°C and 50°C. For Variolink, the 3-mm-thick ceramic group showed lower DC than the 1-mm-thick group only at 25°C, while the self-cure group showed lower DC than the others at all temperatures (p=0.00001). WT decreased with increasing temperature: at 37°C near 70% reduction and at 50°C near 90% for both products, with WT reduction reaching clinically inappropriate times in some cases (p=0.00001). CONCLUSION: Elevated temperature during polymerization of dual-cured cements increased DC. WT was reduced with elevated temperature, but the extent of reduction might not be clinically acceptable.

Influence of the curing mode on fluoride ion release of self-adhesive resin luting cements in water or during pH-cycling regimen.

This study evaluated the effects of curing modes and storage conditions on fluoride release of resin cements. In phase 1, the cumulative fluoride release rate from samples of the resin cements (Panavia F 2.0, RelyX Unicem, MaxCem, and BisCem) was quantified after 15 days storage in water (n=4). In phase 2, the fluoride release profiles from the same materials were analyzed during pH cycling (n=4). In this second phase, fluoride was measured at specific times (one, two, three, five, eight, and 15 days). Disk-shaped specimens were prepared (10 mm × 0.5 mm), and the materials were either light activated or allowed to autopolymerize. For both phases, the fluoride release was measured using a fluoride ion-specific electrode. The fluoride release in water was not affected by the curing mode of RelyX Unicem and Maxcem resin cements. Panavia F. 2.0 and BisCem resin cements, either light cured or autopolymerized modes, released higher amounts of fluoride in water than the other self-adhesive cements. In phase 2, the concentration of fluoride released decreased from the first day of pH cycling until the 15th day for all resin cements, for both curing modes, regardless of the storage solution used (demineralizing/remineralizing). The fluoride release rate during pH cycling by Panavia F 2.0 and MaxCem was not affected by the curing mode. The effect of the curing mode on fluoride ion release in water or during pH cycling was product dependent.

Effect of Argon Plasma Surface Treatment on Repair of Resin Composite Aged Two Years.

OBJECTIVES: To evaluate the effect of argon plasma treatment (PLA) when combined with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) on the shear bond strength (SBS) of a two-year water-aged resin composite bonded to a newly placed composite after 24 hours and one year of water-storage. METHODS AND MATERIALS: Thirty-six light-cured composite plates (20mm x 20mm x 4mm thick) were obtained and stored at 37°C in distilled water for 2 years. These aged plates were distributed into 6 groups (n=6) according to the surface treatment: no treatment (Negative Control); SAN+SIL+HBR (Positive Control); SAN+PLA+SIL+HBR; PLA+ SIL+HBR; PLA+SIL; PLA+HBR. Fresh resin composite cylinders were built up using silicone molds (hole: 1.5 mm high x 1.5 mm diameter) positioned over the aged plates. Half of the SBS samples were stored in distilled water for 24 hours and loaded until failure, while the other half were stored for 1 year before being tested. Data were submitted to two-way analysis of variance and post-hoc Tukey Test (preset alpha of 0.05). RESULTS: Positive Control, SAN+PLA+SIL+HBR and PLA+SIL+HBR groups presented higher SBS means at the 24 hour evaluation. After 1 year of water storage, all groups demonstrated significant SBS reduction, with the SAN+PLA+SIL+HBR group presenting the highest SBS. CONCLUSIONS: Resin plasma treatment in combination with other surface treatments can improve the SBS of composite repairs after one year of water storage. The SBS of the composite repair was not stable over time regardless of the surface treatment.

Cognitive impairment and event-related potentials in paediatric multiple sclerosis: 2-year study.

Approximately, 3-10% of patients with multiple sclerosis (MS) present a disease onset before the age of 18 years. Although growing attention is dedicated to cognitive impairment and its functional consequences in paediatric MS, so far no study has explored possible neurophysiologic correlates. The study's aim was to describe event-related potentials in relationship with cognitive performance in children and adolescents with MS compared with demographically matched healthy controls (HC), providing two-year follow-up data. Six MS subjects aged between 9 and 17 years were assessed through an extensive neuropsychological battery at two time points. Event-related potentials with an odd-ball acoustic paradigm were also recorded in the patients and in nine HC. At baseline, four out of six patients failed three or more cognitive tasks and were classified as cognitively impaired. In all the cognitively impaired patients, we found abnormal latencies and amplitudes of the P300. After 2 years, five patients exhibited a deteriorating cognitive performance and a corresponding deterioration of the P300 parameters. In our group of children and adolescents with MS, changes in P300 parameters proceeded in parallel with deteriorating cognitive performance. P300 might represent an objective parameter to monitor cognitive changes in paediatric MS.

Intrapulpal Concentration of Hydrogen Peroxide of Teeth Restored With Bulk Fill and Conventional Bioactive Composites.

This study evaluated intrapulpal concentration and hydrogen peroxide (HP) penetration at the interface of teeth restored with bioactive composites, using conventional or bulk-fill composites. Cylindrical cavities were prepared on the buccal surface of bovine incisor crowns (n=20) and restored with: resin modified glass-ionomer (RMGI, Riva Light Cure, SDI), non-bioactive bulk-fill composite (FB, Filtek Bulk, 3M Oral Care), non-bioactive conventional composite (FZ, Filtek Z350, 3M Oral Care), bioactive bulk-fill composite (AC, Activa BioActive, Pulpedent), and bioactive conventional composite (BII, Beautifil II, Shofu). After 5,000 thermal cycles, restorations (n=10) were exposed to high (35% HP [4 applications of 8 min/session-4 sessions]) or low (9.5% HP [30 min/day-14 days]) concentration bleaching protocols. After the last bleaching application, the HP intrapulpal concentration was determined. Additional teeth were restored, pigmented with rhodamine B solution, and HP penetration around the interface was observed under laser scanning confocal fluorescence microscopy (LSCFM, n=3). The presence of gaps at the interface was observed on replicas of the cross-sectioned samples under scanning electron microscopy (SEM, n=5). Data were submitted to one-way (gap analysis) and twoway analysis of variance (ANOVA; HP intrapulpal concentration) and Tukey test (α=0.05). The LSCFM images were qualitatively analyzed. The restored teeth submitted to 35% HP presented higher HP intrapulpal concentration than teeth submitted to 9.5% HP (p<0.05). No differences in HP intrapulpal concentration was observed among groups (p>0.05) when exposed to 9.5% HP. Lower HP intrapulpal concentration was observed for teeth restored with RMGI exposed to HP 35%, when compared with teeth restored with nonbioactive conventional (FZ; p=0.004) and bulk-fill composites (FB; p=0.01). No gap formation was observed at the outer enamel adhesive interface for all restorative materials. LSCFM images showed that 35% HP promoted greater degradation of rhodamine B at the enamel, except for RMGI. In this context, RMGI promoted lower HP intrapulpal concentration than non-bioactive conventional and bulk-fill composites.

Cognitive impairment in early stages of multiple sclerosis.

Cognitive dysfunction involves 40-65% of multiple sclerosis patients and can have a great functional impact. It can be detected in all the disease phenotypes since the early stages of the disease, and tends to progress over time. Memory, complex attention, information-processing speed and executive functions are most commonly involved. The relationship between cognitive changes and magnetic resonance imaging (MRI) findings may involve changes in different areas, including white matter lesions, cortical and deep grey matter and normal appearing brain tissue on conventional MRI. The search for effective therapeutic strategies is a major undertaking, involving the use of both pharmacologic and rehabilitative approaches. Early treatment with disease-modifying drugs that can contain the disease burden in the brain seems to be highly advisable in order to prevent or delay the development of cognitive impairment.

Incidence of allergic diseases in an elderly population.

Recent years have shown a progressive increase of allergic disease in the elderly population worldwide. Naturally, this phenomenon has coincided with attempts to guarantee the best possible quality of life for this age group. As a result, diseases that were previously overlooked are attracting ever greater attention. An epidemiological study of allergic manifestations in the elderly conducted in all consecutive patients referred to an Allergology Unit over a three-month period at the beginning of 2008 showed that 15% belonged to the elderly population and among these, 51.8 % were suffering from an allergic reaction to drugs. Skin manifestations, including both urticaria and eczema, accounted for 71.4% of cases but only in 13.8% of these patients was there a diagnosis of an allergic reaction made and the allergen responsible individuated. Rhinitis was present in 16.8 % of the patients and food allergy in 8 %. Certainly, age-induced modifications in the immunological system can be responsible for allergic reactions. In fact, non specific immunity components such as the production of mucus or a reduced function of the T- and IL-2 cells can induce the onset of symptoms referable to allergic disease. Further studies are ongoing to gain a better understanding of the pathogenic mechanisms that could justify the development in the elderly population of a cytokine phenotype that is more prone to develop allergic manifestations, and to assess the true incidence of respiratory, food and drug allergies in this stage of life.

Effect of Curing Light and Exposure Time on the Polymerization of Bulk-Fill Resin-Based Composites in Molar Teeth.

OBJECTIVES: This study examined the influence of different light-curing units (LCUs) and exposure times on the microhardness across bulk-fill resin-based composite (RBC) restorations in a molar tooth. METHODS AND MATERIALS: Tip diameter, radiant power, radiant exitance, emission spectra, and light beam profile were measured on two single-emission-peak LCUs (Celalux 3 and DeepCure-S) and two multiple-peak LCUs (Bluephase 20i and Valo Grand). A mold was made using a human molar that had a 12-mm mesial-distal length, a 2.5-mm deep occlusal box, and two 4.5-mm deep proximal boxes. Two bulk-fill RBCs (Filtek Bulk Fill Posterior and Tetric EvoCeram Bulk Fill) were photoactivated for 10 seconds and for 20 seconds, with the light guide positioned at the center of the occlusal surface. Microhardness was then measured across the transverse surface of the restorations. The light that reached the bottom of the proximal boxes was examined. Data were statistically analyzed with the Student t-test, two-way analysis of variance, and the Tukey post hoc test (α=0.05). RESULTS: The four LCUs were different regarding all the tested characteristics. Even when using LCUs with wide tips and a homogeneous beam profile, there were significant differences in the microhardness results obtained at the central and proximal regions of the RBCs (p<0.05). LCUs with wider tips used for 20 seconds produced higher microhardness values (p<0.05). The multiple-peak LCUs produced greater hardness values in Tetric EvoCeram Bulk Fill than did the single-emission-peak LCUs (Celalux 3 and DeepCure-S). Results for the light measured at the bottom of proximal boxes showed that little light reached these regions when the light tip was positioned at the center of restorations. CONCLUSIONS: Curing lights with wide tips, homogeneous light beam profiles, and longer exposure times are preferred when light-curing large MOD restorations. Light curing from more than one position may be required for adequate photopolymerization.

Does the Type of Solvent in Dental Adhesives Influence the Clinical Performance of Composite Restorations Placed in Noncarious Cervical Lesions? A Systematic Review and Meta-analysis.

CLINICAL RELEVANCE: According to the clinical and scientific evidence presented in this systematic review and meta-analysis, dental adhesives containing either organic solvent (acetone or alcohol) can be used to achieve similar clinical performance and longevity of composite restorations. SUMMARY: Objectives: This systematic review and meta-analysis compared the clinical performance and survival rates of composite restorations placed in noncarious cervical lesions (NCCLs) using dental adhesives containing acetone or alcohol-based solvents.Methods and Materials: PubMed, Scopus, Web of Science, Virtual Health Library (VHL) LILACS, Cochrane Library, OpenGrey, Clinical Trials, and Rebec were searched. MeSH terms, supplementary concepts, synonyms, and free keywords were used in the search strategy. All references were crosschecked by two independent investigators following the PICOS strategy (population, NCCLs; intervention, acetone-based bonding agent; comparison, alcohol-based bonding agent; outcome, clinical evaluation parameters and survival rates; study design, randomized controlled clinical trials). Cochrane Collaboration's tool was used to assess risk of bias, and two distinct meta-analyses were performed using the RevMan software. The prevalence of success and the total number of restorations for each group (acetone- or alcohol-based) were used to calculate the risk difference at a confidence interval of 95%. Random-effects models were applied, and heterogeneity was assessed using the I2 index in the pooled and subgrouped meta-analyses. The certainty of evidence was evaluated through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.Results: A total of 7876 studies were retrieved, from which 27 studies were selected for the systematic review. Ten studies were classified as "low risk of bias" and included in the meta-analyses. Overall heterogeneity was not significant (I2 = 0.00%). The clinical performance of restorations placed with bonding agents based on both solvents for each of the available parameters presented no statistical significance for any of the meta-analyses (p>0.05).Conclusion: Scientific evidence suggests composite restorations placed with acetone or alcohol-based dental adhesives present similar clinical performance and survival rates in NCCLs.

Influence of Multiple Peak Light-emitting-diode Curing Unit Beam Homogenization Tips on Microhardness of Resin Composites.

This study evaluated the effect of light curing unit (LCU) guide type (regular or homogenizing) on top and bottom microhardness of conventional and bulk-fill resin-based composites (RBCs). A polywave light-emitting-diode (LED) LCU (Bluephase Style, Ivoclar Vivadent AG) was used with two different light guides: a regular tip (RT, 935 mW/cm2 emittance) and a homogenizer tip (HT, 851 mW/cm2 emittance). Two conventional RBCs (Herculite Ultra [HER], Kerr Corp; Tetric EvoCeram [TEC], Ivoclar Vivadent AG) and two bulk-fill RBCs (SonicFill [SOF], Kerr Corp; Tetric EvoCeram Bulk Fill [TBF], Ivoclar Vivadent AG) were tested. Disc-shaped samples (10 mm Ø), 2-mm thick for conventional composites and 4-mm thick for bulk-fill composites were prepared. Samples were light cured according to manufacturer-recommended times. Knoop microhardness values (KHN) were obtained on the top and bottom surfaces of each specimen at locations correlated with the output of the three LED chips emitting blue (456 nm) or violet light (409 nm). Beam profile analysis using both light guides was also performed. Microhardness of each composite was analyzed using three-way analysis of variance and Tukey honestly significant difference post hoc test (α=0.05). Beam profile images showed better light distribution across the surface of the HT light guide. Use of the HT decreased KHN of HER at the locations of the blue LED chips at bottom of the sample but had no effect on the top surface. For TEC, use of HT increased KHN of all three LED locations at the top surface. Use of the HT increased KHN of SOF at locations corresponding to one of the blue and the violet LED chips at the bottom surface. For TBF, HT increased KHN at all top surface locations. All RBCs showed higher mean KHN at the top compared with the bottom surfaces. In general, all composites presented a higher KHN at the blue LED areas regardless of the surface or the tip used. Results suggest that the homogenizer light guide resulted in significantly increased microhardness at the top, in composite resins containing alternative photoinitiators; however, that effect was not observed at the bottom surfaces.