Effects of natural products-based dentifrices on acrylic resin for denture bases: A simulated period of 4 years.

PURPOSE: To evaluate the antimicrobial activity of dentifrices based on Malva sylvestris and propolis and the effect on the acrylic resin. METHODS: The inhibitory effect against Candida albicans, Enterococcus faecalis and Streptococcus mutans was determined. The specimens of resin were divided into groups: Control (brushing with distilled water); brushing with Colgate; brushing with Protex; brushing with Malvatricin, brushing with Proporalcare Dental Gel and brushing with Green Propolis Dental Gel. Brushing was carried out in a brushing machine. Roughness and color were assessed. The data were analyzed by ANOVA, followed by the Bonferroni post test (α= 0.05). RESULTS: The products evaluated showed antimicrobial activity against all microorganisms (P< 0.05), except Proporalcare Dental Gel, which was not effective against E. faecalis. Greater roughness (P< 0.05) was observed in the samples treated with Colgate. The samples from control and Protex groups showed the lowest color variation and the highest luminosity, with a difference in relation to the others (P< 0.05), which showed higher values, although clinically acceptable. CLINICAL SIGNIFICANCE: The dentifrices based on natural products can be indicated for cleaning prostheses, since they showed antimicrobial activity and did not cause perceptible color changes of the resin tested. The dentifrices did not produce adverse effects on the surface of the resin or did so less than the conventional dentifrice.

Development, Validation, and Evaluation of the Pediatric Inflammatory Crohn's Magnetic Resonance Enterography Index From the ImageKids Study.

BACKGROUND & AIMS: Cross-sectional imaging is important in the assessment of transmural inflammation in Crohn's disease (CD). Small bowel involvement is often more extensive in pediatric CD, requiring a panentering measuring tool. We undertook to develop a magnetic resonance enterography (MRE)-based index that would measure inflammation in all segments of the intestine, without rectal contrast. METHODS: Children with CD underwent ileocolonoscopy and MRE and half were prospectively followed for 18 months when MRE was repeated. Item generation and reduction were performed by a Delphi panel of pediatric radiologists, a systematic literature review, a cross-sectional study of 48 MREs, and a steering committee. Formatting and weighting were performed using multivariate modeling adjusted by a steering committee. MREs were read locally and centrally. Reliability, validity, and responsiveness were determined using several clinimetric and psychometric approaches. RESULTS: Thirty items were initially generated and reduced to 5 using regression analysis on 159 MREs: wall thickness, wall diffusion weighted imaging, ulcerations, mesenteric edema, and comb sign. In the validation cohort of 81 MREs, the weighted global PICMI correlated well with the radiologist global assessment (r = 0.85; P < .001) and with the simple endoscopic score in a subsample with ileocolonic disease (r = 0.63; P < .001). Interobserver and test-retest reliability were high (interclass correlation coefficients, 0.84; 95% confidence interval [CI], 0.79-0.87; and 0.81, 95% CI, 0.65-0.90, respectively; both P < .001). Excellent responsiveness was found at repeated visits (n = 116 MREs; area under the receiver operating characteristic curve 0.96; 95% CI, 0.93-0.99). Transmural healing was defined as PICMI ≤10 and response as a change of >20 points with excellent discriminative validity (area under the receiver operating characteristic curve = 0.96; 95% CI, 0.93-0.99). CONCLUSIONS: The PICMI is a valid, reliable, and responsive index for assessing transmural inflammation in pediatric CD. It scores the entire bowel length and does not require intravenous contrast or rectal enema and, therefore, is suitable for use in children. (ClinicalTrials.gov, Number: NCT01881490.).

Serum MOG-IgG in children meeting multiple sclerosis diagnostic criteria.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is now recognized as distinct from multiple sclerosis (MS). OBJECTIVE: To evaluate the importance of considering myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin-G (IgG) serology when applying MS diagnostic criteria in children. METHODS: Within a prospective cohort of children meeting MS criteria (median follow-up = 6 years, interquartile range (IQR) = 4-9), we measured MOG-IgG in serial archived serum obtained from presentation, and compared imaging and clinical features between seropositive and seronegative participants. RESULTS: Of 65 children meeting MS criteria (median age = 14.0 years, IQR = 10.9-15.1), 12 (18%) had MOG-IgG at disease onset. Seropositive participants were younger, had brain magnetic resonance imaging (MRI) features atypical for MS, rarely had cerebrospinal fluid (CSF) oligoclonal bands (2/8, 25%), and accumulated fewer T2 lesions over time. On serial samples, 5/12 (42%) were persistently seropositive, 5/12 (42%) became seronegative, and 2/12 (17%) had fluctuating results. All 12 children experienced a disease course different from typical MS. CONCLUSION: While children with MOG-IgG can have clinical, CSF, and MRI features conforming to MS criteria, the presence of MOG-IgG is associated with atypical features and predicts a non-MS disease course. Given MOG-IgG seropositivity can wane over time, testing at first attack is of considerable importance for the diagnosis of MOGAD.

Scaling Exponent of Human Gait: A Scoping Review.

Nonlinear analysis such as detrended fluctuation analysis (DFA) and power spectrum density are often used to describe the gait motor behavior. This is an interdisciplinary effort to understand and evaluate human movement by the complexity field lenses. However, there are conflicting interpretations about the measures. For instance, the same alpha value could be a better adaptation or sign of pathology. Therefore, the purposes of this scope review are: to map scientific production in the application of the scaling exponent for gait and running analysis, identify the scaling methods used in these studies and the results interpretation, and identify knowledge gaps for future studies. Eleven methods and six metrics associated with them were found. Most of the papers use DFA and explain the results through hypotheses about the supraspinal influence and origin of long-range correlations, adaptability and stability during gait and running. Comparing studies and interpretations, we found a broad designation of terms for the same metric. This reflects the lack of agreement and language uniformity in this literature.

Comparison of oral microbiome profile of polymers modified with silver and vanadium base nanomaterial by next-generation sequencing.

This study aimed to evaluate two methods of the incorporation of nanostructured silver vanadate decorated with silver nanoparticles (AgVO3) into acrylic resin and characterize the profile of early and late microbial communities in class and family taxonomic level by pyrosequencing. The specimens were made by adding different concentrations of AgVO3 (1, 2.5, and 5%) to the heat-activated acrylic resin by two methods: vacuum spatulation (VS) and polymeric film (PF). A control group (0%) without AgVO3 was also obtained for both methods. After 24 h and 7 days of incubation in human saliva, biofilm samples were collected, DNA was extracted, and 16S rRNA genes were sequenced by the 454-Roche sequencing platform. Seventeen classes and 51 families of bacteria were identified. The abundance of Bacteroidia, Bacilli, Negativicutes, Fusobacteria and Betaproteobacteria classes decreased after 7 days of incubation, and Clostridia, Gammaproteobacteria, and unclassified bacteria increased. The Negativicutes and Betaproteobacteria classes were more abundant when the PF method was used, and Gammaproteobacteria was more abundant when VS was used. The incorporation of 5% AgVO3 promoted a reduction in the prevalence of Bacilli, Clostridia, Negativicutes, Betaproteobacteria, and unclassified bacteria, and increased Gammaproteobacteria. The addition of AgVO3 to acrylic resin altered the early and mature microbiome formed on the specimen surface, and the PF method presented a more favorable microbial profile than the VS method.

Effect of saliva and beverages on the surface roughness and hardnessof acrylic resin modified with nanomaterial.

PURPOSE: To evaluate the surface roughness and hardness of thermopolymerized acrylic resin incorporated with nanostructured silver vanadate (AgVO3) subjected to saliva and beverages. METHODS: The 128 specimens (5×5×2 mm) were prepared in thermopolymerized acrylic resin, according to the AgVO3 concentrations (n=32): 0%, 2.5%, 5% and 10%. The roughness and hardness were analyzed before and after immersion in saliva, Coca-Cola, orange juice and red wine, for 12 and 24 days. 2-way ANOVA and Bonferroni test (α= 0.05) were performed. RESULTS: After 12 days, Coca-Cola caused the highest roughness increase in the 2.5% group. The 10% group with saliva presented a higher roughness increase (P= 0.009). The control presented a decrease in roughness when in beverages (P< 0.05). After 24 days, orange juice and Coca-Cola produced a higher decrease in roughness in the control group (P< 0.05). After 12 days, saliva and wine produced a higher decrease in hardness of the 2.5% group (P< 0.05). Coca-Cola produced a decrease in hardness and wine an increase in hardness in the group with 10% AgVO3 concentration (P< 0.05). After 24 days, the group with 2.5% presented the highest decrease in hardness (P< 0.05). The immersions produced decreased hardness in the acrylic resin. Initially, there was an increase in roughness, however, over time, it decreased. CLINICAL SIGNIFICANCE: The control of oral biofilm is fundamental for the maintenance of the patient's oral health; however the incorporation of antimicrobial nanomaterial into prosthetic materials frequently exposed to saliva and beverages in the oral cavity interfered with the physical-mechanical properties of the products tested.

Cytotoxicity and release ions of endodontic sealers incorporated with a silver and vanadium base nanomaterial.

The modification of endodontic sealers with nanoparticles to confer antimicrobial activity allow greater effect, with interaction at a molecular level. The nanostructured silver vanadate decorated with silver nanoparticles (AgVO3) is a nanomaterial unprecedented in dentistry for this application. This study incorporated the AgVO3 into three endodontic sealers of different compositions and evaluate the cytotoxicity and release of compounds. The groups of commercially available AH Plus, Sealer 26, and Endomethasone N and groups of the same sealers with incorporated AgVO3 (at concentrations 2.5, 5, 10%) were prepared, and extracts of the specimens were obtained for 24 h. The cell viability (cytotoxicity) of human gingival fibroblasts (HGF) was assessed after 24 h, 7 and 14 days. Silver (Ag+) and vanadium (V4+/V5+) ion release was quantified after 24 h by ICP-MS. Data were analyzed by Kruskal-Wallis and Dunn's post-hoc (α = 0.05). The cell viability was inversely proportional to treatment time. The Sealer 26 and Endomethasone N groups were cytotoxic for HGF cells, regardless of the incorporation of the AgVO3 (p > 0.05), and the incorporation reduced cell viability of AH Plus (p < 0.05). The release of ions was proportional to the concentration of AgVO3. AH Plus released more Ag+ ions, and Sealer 26 and Endomethasone N releases more V4+/V5+ ions. In conclusion, it was not possible to confirm the influence of AgVO3 on HGF cell viability to Sealer 26 and Endomethasone N, however, nanomaterial influenced cell-viability to AH Plus, so the commercial sealers can be cytotoxic in synergy with the nanomaterial. The release of Ag+ and V4+/V5+ was proportional to the AgVO3 incorporated.

Influence of Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin.

This in vitro study evaluated the influence of the Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin. Eighty dentin specimens were selected and divided into eight groups (n = 10): G1: negative control; G2: positive control (5% fluoride varnish-FV); G3: Er,Cr:YSGG laser; G4: FV + laser; G5: 3% potassium oxalate; G6: 3% potassium oxalate + laser; G7: biphasic calcium silicate/phosphate gel (gel); G8: gel + laser. Laser parameters: 0.5 W, 6.25 J/cm2 at 1-mm distance. The erosive drink used was a cola soft-drink (pH = 2.42 at 4 °C), lasting 5 min, twice a day, with 6-h intervals between the challenges, during 14 days. Kolmogorov-Smirnov and Levene's tests were satisfied. The surface roughness data were submitted to ANOVA and Tukey post hoc tests. For the wear profile, Kruskal-Wallis and Dunn post hoc tests were used. Afterwards, the Spearman correlation test was performed. All statistical tests assumed a significance level of 5% (α = 0.05). G1 presented the highest surface roughness value after the erosive challenge (3.586 µm2 ± 0.205 µm2) and the G7 presented the lowest surface roughness value after the erosive challenge (1.071 µm2 ± 0.180 µm2). For the lost volume, G4 presented the lowest percentage (9.7% ± 0.9%), while G1 had the highest percentage (41.8% ± 2.5%), both with p < 0.05. There was a weak correlation between the response variables (ρ = 0.33). All groups presented lower values of surface roughness and loss of volume when compared to the negative control group. For the surface roughness, the biphasic calcium silicate/phosphate gel presented the best result. For volume loss, the 5% fluoride varnish + Er,Cr:YSGG laser showed the best results compared to the other groups.

Influence of Er,Cr:YSGG laser on dentin acid resistance after erosive challenge.

PURPOSE: To evaluate the influence of the Er,Cr:YSGG laser with or without the 5% fluoride varnish on the acid resistance of dentin after erosive challenge. METHODS: 36 incisors were selected and sectioned, obtaining 72 specimens of 4 mm × 4 mm and randomly divided into eight groups (n = 9). In G1: application of Er,Cr:YSGG (0.1W; 5Hz, air 55%); G2: laser (0.25W; 5Hz, air 55%); G3: fluoride varnish + laser (0.1W; 5Hz, air 55%); G4: fluoride varnish + laser (0.25W, 5Hz, air 55%); G5: fluoride varnish + laser (0.1W; 5Hz, without air); G6: fluoride varnish + laser (0.25W, 5Hz, without air); G7: fluoride varnish and G8: no treatment. When used, the laser was irradiated without water cooling, scanning mode during 10 seconds. The surface roughness data were subjected to ANOVA. For wear profile, we used Kruskal-Wallis test and Dunn post-hoc, all with α= 0.05. RESULTS: The results showed no statistically significant difference when comparing the groups as regards to the surface roughness (P> 0.05). Regarding the percentage of lost volume, the G5 and G6 groups presented the best results (G5 = 7.8% and G6 = 8.5%), with the lowest loss of dentin volume compared to other groups (P< 0.05). The G8 group (no treatment) had the highest lost volume (G8 = 39.1% followed by the G7 group (fluoride varnish), which had 25.9%. CLINICAL SIGNIFICANCE: The use of Er,Cr:YSGG laser and fluoride varnish can be an effective method to increase the acid resistance of dentin after erosive challenges, and limit problems related to hypersensitivity.

Development of an Impression Material with Antimicrobial Properties for Dental Application.

PURPOSE: To evaluate the antimicrobial activity and physico-mechanical properties of an irreversible hydrocolloid in which nanostructured silver vanadate decorated with silver nanoparticles (AgVO3 ) was added at various concentrations (0% - control, 2.5%, 5%, and 10% by weight). MATERIALS AND METHODS: The agar diffusion method (n = 10) was used to evaluate the inhibitory effect on the following species: Streptococcus mutans, Staphyloccocus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The gelation time, flow capacity and plastic deformation were verified (n = 10). The data were analyzed using the Kruskal-Wallis test followed by the Dunn post-test, or via one-way ANOVA with multiple comparisons with a Bonferroni adjustment depending on the distribution (α = 0.05). RESULTS: All percentages of the nanomaterial were able to promote the antimicrobial activity of a hydrocolloid, with the formation of an inhibition zone (p < 0.05). In general, there was a dose-dependent effect on antimicrobial activity: higher concentrations of the nanomaterial promoted greater action except in the cases of P. aeruginosa (p < 0.001; F = 51.74) and S. aureus (p < 0.001), where the highest inhibition was for the 2.5% group. No difference was found in the gelation time when the control was compared with the groups with AgVO3 (p > 0.05). The difference was between the 5% and 10% groups (p = 0.007), and the latter promoted an increase in time. The flow capacity of the hydrocolloid with 5% of AgVO3 was significantly lower when compared with the control (p = 0.034). The AgVO3 influenced the plastic deformation (p < 0.001) in such a way that concentrations of 5% (p = 0.010) and 10% (p < 0.001) promoted an increase in this property when compared with the control. CONCLUSIONS: AgVO3 can be incorporated into an irreversible hydrocolloid as an antimicrobial agent without promoting adverse effects on physical-mechanical properties when used in concentrations of 2.5%.

Surface treatment of implant materials with antimicrobial nanoparticulates.

This study analyzed nanostructured silver vanadate (AgVO3) films on certain substrate surfaces found in dental implant devices in order to see if these films promote antimicrobial activity. Enamel and glaze vehicles were used to apply the nanomaterial (0.0% [control], 2.5%, 5.0%, and 10.0% concentrations) on 3 substrates (280 specimens per substrate): polytetrafluoroethylene (PTFE), polyacetal, and acrylic resin. An agar diffusion method was performed in triplicate to determine the antimicrobial activity against 8 microorganisms. Physical behavior and morphologic properties were also analyzed. The growth of Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, and Staphylococcus aureus was inhibited with the application of AgVO3. For Candida albicans, Porphyromonas gingivalis, and Prevotella intermedia, no antimicrobial activity was observed. Except for S mutans, the type of substrate did not influence the microbiologic results. The glaze showed greater antimicrobial efficacy against S aureus, E faecalis, and S mutans than did the enamel vehicle (P < 0.05). Films with 10% AgVO3 showed greater antimicrobial activity (P < 0.05). The choice of substrate or vehicle did not influence the surface roughness (P > 0.05); however, the application of 10% AgVO3 caused greater surface change (P < 0.05). The application of the nanomaterial did not influence the surface hardness of substrates when compared with the control group (P > 0.05). The use of the glaze as a vehicle provided higher hardness values (P < 0.05).

Perianal Pediatric Crohn Disease Is Associated With a Distinct Phenotype and Greater Inflammatory Burden.

OBJECTIVES: Data on the outcomes of children with perianal Crohn disease (pCD) are limited, although its presence is often used for justifying early use of biologics. We aimed to assess whether pCD in children is associated with more severe outcomes as found in adults. METHODS: Data were extracted from the ImageKids database, a prospective, multicenter, longitudinal cohort study. The study enrolled 246 children at disease onset or thereafter. All patients underwent comprehensive clinical, endoscopic, and radiologic evaluation at enrollment; 98 children had repeat evaluation at 18 months. RESULTS: Of the 234 included patients (mean age 14.2 ±â€Š2.4 years; 131 [56%] boys), 57 (24%) had perianal findings, whereas only 21 (9%) had fistulizing perianal disease. Children with pCD had reduced weight and height z scores compared with non-pCD patients (-0.9 vs -0.35, P = 0.03 and -0.68 vs -0.23, respectively; P = 0.04), higher weighted pediatric CD activity index (32 [interquartile range 16-50] vs 20 [8-37]; P = 0.004), lower serum albumin (3.6 ±â€Š0.7 vs 4.5 ±â€Š0.8, P = 0.016), and higher magnetic resonance enterography global inflammatory score (P = 0.04). Children with pCD had more rectal (57% vs 38%, P = 0.04), and jejunal involvement (31% vs 11% P = 0.003) and a higher prevalence of granulomas (64% vs 23%, P = 0.0001). Magnetic resonance enterography-based damage scores did not differ between groups. Patients with skin tags/fissures only, had similar clinical, endoscopic, and radiologic characteristics as patients with no perianal findings. CONCLUSIONS: Pediatric patients with pCD with fistulizing disease have distinct phenotypic features and a predisposition to a greater inflammatory burden.

Effect of casting atmosphere on the marginal deficiency and misfit of Ni-Cr alloys with and without beryllium.

STATEMENT OF PROBLEM: The marginal adaptation of prosthetic crowns is still a significant clinical problem. PURPOSE: The purpose of this in vitro study was to evaluate the marginal deficiency and misfit of Ni-Cr alloys with and without beryllium under different casting conditions. MATERIAL AND METHODS: Four casting conditions were selected: flame-torch, induction/argon, induction/vacuum, and induction/air; and 2 alloys were used, Ni-Cr-Be and Ni-Cr. For each group, 10 metal specimens were prepared. Silicone indirect impressions and analysis of the degree of rounding were used to evaluate the marginal deficiencies of metal copings, and a standardized device for the setting pressure associated with optical microscopy was used to analyze the marginal misfit. Results were evaluated with 2-way ANOVA (α=.05), followed by the Tukey honest significant difference post hoc test, and the Pearson correlation test (α=.05). RESULTS: Alloy (P<.001) and casting technique (P<.001) were shown to affect marginal deficiencies. The Ni-Cr cast using the torch technique showed the highest marginal deficiency, and the Ni-Cr-Be cast in a controlled argon atmosphere showed the lowest (P<.001). Alloy (P=.472) and casting techniques (P=.206) did not affect the marginal misfit, but significant differences were found in the interaction (P=.001); the lowest misfit was achieved using the Ni-Cr-Be, and the highest misfit occurred with the molten Ni-Cr, using the cast torch technique. No correlation was found between deficiency and marginal misfit (r=.04, P=.69). CONCLUSIONS: The interactions demonstrated that the alloy containing beryllium that was cast in an argon atmosphere led to reduced marginal deficiency. Improved marginal adaptation can be achieved for the same alloy by using the torch technique.

Elemental ion release and cytotoxicity of antimicrobial acrylic resins incorporated with nanomaterial.

OBJECTIVES: This study evaluated the release of ions and the cytotoxicity of acrylic resins incorporated with silver vanadate decorated with silver nanoparticles (AgVO3 ). BACKGROUND: The inhibition of the accumulation of microorganisms on the resins is critical in preventing diseases. However, the hypothesis is that the release of ions from the incorporation of AgVO3 may be important in biocompatibility. MATERIALS AND METHODS: Specimens of autopolymerising (AP) and heat-polymerising resin (HP) with AgVO3 were prepared and immersed in culture medium. The release of silver ions (Ag) and vanadium (V) was evaluated by mass spectrometry with inductively coupled plasma (ICP-MS) (n=9) and the cell viability of fibroblasts L929 by MTT (3-[4,5-dimethylthiazol- 2yl]-2,5-diphenyltetrazolium bromide) (n=12). The results were evaluated with analysis of variance (ANOVA), Tukey and Pearson correlation test (α=.05). RESULTS: The groups containing AgVO3 presented a difference in relation to the control (0%) regarding the release of Ag and V (P<.0001). All groups showed a reduction in L929 viability when compared with the cellular control (100%) (P<.0001). In comparison with the control resins for HP, a reduction in the metabolism of cells occurred starting at 2.5% and for AP at 5% (P<.0001). A positive correlation was found between the concentration of AgVO3 and the ion release, and a negative between the ion release and the cell viability. CONCLUSIONS: Significant numbers of Ag and V ions were released from resins with higher concentrations of AgVO3 , presenting cytotoxicity for cells, suggesting that the use of low concentrations is indicated to avoid risks to patients.

In vitro study of the antibacterial properties and impact strength of dental acrylic resins modified with a nanomaterial.

STATEMENT OF PROBLEM: The accumulation of bacteria on the surface of dental prostheses can lead to systemic disease. PURPOSE: The purpose of this in vitro study was to evaluate the growth of Staphylococcus aureus and Pseudomonas aeruginosa on the surface of autopolymerizing (AP) and heat-polymerizing (HP) acrylic resins incorporated with nanostructured silver vanadate (ß-AgVO3) and its impact strength. MATERIAL AND METHODS: For each resin, 216 circular specimens (9 × 2 mm) were prepared for microbiologic analysis and 60 rectangular specimens (65 × 10 × 3.3 mm) for mechanical analysis, according to the percentage of ß-AgVO3: 0%, control group; 0.5%; 1%; 2.5%; 5%; and 10%. After a biofilm had formed, the metabolic activity of the bacteria was measured using the XTT reduction assay (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) (n=8), and the number of viable cells was determined by counting colony forming units per milliliter (CFU/mL) (n=8). Confocal laser scanning microscopy (CLSM) was used to complement the analyses (n=2). The mechanical behavior was evaluated by impact strength assays (n=10). Data were analyzed by 2-way ANOVA, followed by the Tukey honestly significant difference (HSD) post hoc test (α=.05). RESULTS: The addition of 5% and 10% ß-AgVO3 significantly decreased the metabolic activity of P. aeruginosa for both resins (P<.05). The HP resin promoted a greater reduction in metabolic activity than the AP resin (P<.05). No difference was found in the metabolic activity of S. aureus according to the XTT (P>.05). The number of CFU/mL for S. aureus and P. aeruginosa decreased significantly when 5% and 10% ß-AgVO3 were added (P<.001). These concentrations significantly reduced the impact strength of the resins (P<.001) because the system was weakened by the presence of clusters of ß-AgVO3. CONCLUSION: The addition of ß-AgVO3 can provide acrylic resins with antibacterial activity but reduces their impact strength. More efficient addition methods should be investigated.

Mechanical properties of silorane-based and methacrylate-based composite resins after artificial aging.

The aim of this study was to compare the compressive strength of a silorane-based composite resin (Filtek P90) to that of conventional composite resins (Charisma, Filtek Z250, Fill Magic, and NT Premium) before and after accelerated artificial aging (AAA). For each composite resin, 16 cylindrical specimens were prepared and divided into 2 groups. One group underwent analysis of compressive strength in a universal testing machine 24 hours after preparation, and the other was subjected first to 192 hours of AAA and then the compressive strength test. Data were analyzed by analysis of variance, followed by the Tukey HSD post hoc test (α = 0.05). Some statistically significant differences in compressive strength were found among the commercial brands (P < 0.001). The conventional composite resin Fill Magic presented the best performance before (P < 0.05) and after AAA (P < 0.05). Values for compressive strength of the silorane-based composite were among the lowest obtained, both before and after aging. Comparison of each material before and after AAA revealed that the aging process did not influence the compressive strength of the tested resins (P = 0.785).

Analysis of the influence of implant shape on primary stability using the correlation of multiple methods.

OBJECTIVES: The purpose of this study was to analyze the influence of the shape of various implants and the density of substrate on primary stability using a combination of methods. MATERIALS AND METHODS: Fifty-four Neodent® brand cylindrical and conical implants with different prosthetic platforms were used. Implants were inserted into a pork rib bone and polyurethane blocks. Primary stability was assessed by insertion torque (IT), resonance frequency analysis (RFA), and pullout strength. Screws were also analyzed by scanning electron microscopy (SEM) before insertion and after removal to justify their use for inserting in different substrates. RESULTS: The conical cone morse implant had the highest average for all of the assays performed and was significantly different (p < 0.05) from the cylindrical implants for IT in the bone, pullout strength in the 40 per cubic foot (PCF) polyurethane, and the bone. The internal hex cylindrical implant had the lowest averages, which were significantly different (p < 0.05) from the conical implants for IT and RFA in the bone, pullout strength in the 40 PCF polyurethane, and the bone. The IT, RFA, and pullout strength assays were moderately correlated, and the photomicrographs did not reveal changes in the implants. CONCLUSIONS: The analysis of different implants showed a better primary stability of tapered implants; the density of the substrate influences the primary stability and the 15 PCF polyurethane was not adequate to evaluate primary stability; correlation was obtained between the different methodologies of analysis of primary stability. CLINICAL RELEVANCE: The study shows the influence of different implant macro-geometries and densities of substrates on primary stability.

The role of diagnostic imaging and liver biopsy in the diagnosis of focal nodular hyperplasia in children.

BACKGROUND & AIMS: Focal nodular hyperplasia (FNH), a benign liver tumour, has a characteristic appearance on diagnostic imaging (DI) and histology. The role of liver biopsy in children for the diagnosis of FNH is unclear. This study investigates the diagnostic accuracy of DI for FNH in children without comorbidities, compared to liver biopsy. METHODS: A total of 304 consecutive patients (age <18 years) with a biopsied liver mass were retrospectively ascertained (1990-2010). Individuals with a history of malignancy, liver disease or syndromes with increased malignancy risk were excluded. DI and biopsy data were reviewed. RESULTS: After excluding 205 cases, 99 liver masses were studied. Based on histology, the most common diagnosis was hepatoblastoma (46/99, 44%) followed by FNH (23/99, 23%). The mean age at FNH diagnosis was 11.1 ± 5.2 years, with female preponderance (78%), and a median follow-up of 1.35 years (interquartile range 0.54, 4.20 years). 19/23 biopsy-proven FNH met standard criteria for FNH on DI. In 4/23 cases of biopsy-proven FNH, imaging did not suggest FNH. Two false positive cases included adenoma and fibrolamellar hepatocellular carcinoma. On review of original reports, DI had 82.6% sensitivity and 97.4% specificity for the diagnosis of FNH. On blind review, the sensitivity of DI for FNH diagnosis was 81.3% for MRI (13/16), and 53.3% for CT (8/15). CONCLUSIONS: In this cohort of children with liver masses and no comorbidities, a diagnosis of FNH by imaging was highly specific, and MRI was the most sensitive study for its diagnosis. Liver biopsy may be deferred in selected children if the DI, particularly MRI, is indicative of FNH.

Influence of Er:YAG and ND:YAG laser irradiation and fluoride application on surface roughness and dentin surface wear after erosive challenge - An in vitro study.

Background: To evaluate the effectiveness of Er:YAG and Nd:YAG laser on dentin hypersensitivity prevention, associated or not to acidulated phosphate fluoride (APF) after erosive challenge. Material and Methods: 104 specimens were obtained from bovine dentine and divided into groups (n=13): G1: Er:YAG; G2: Er:YAG followed by application of APF; G3: application of APF followed by Er:YAG, simultaneously; G4: Nd:YAG; G5: Nd:YAG followed by application of APF; G6: application of APF followed by Nd:YAG, simultaneously; G7:application of APF; G8: untreated. The parameters for Er:YAG were:10s, distance of 4mm, water cooling flow of 2mL/min, 2Hz, 3.92J/cm2. For the Nd:YAG: 10s, distance of 1mm, without cooling, 10Hz, 70.7J/cm2. The erosive drink was a cola at 4°C, 3×/day for 1 minute, for 5 days. Roughness and wear analysis were done in confocal laser microscope. Data were statistically analyzed (α=0.05). Results: As regards roughness, there was no statistically difference among the groups. The groups irradiated with Er:YAG had a volume loss lower. G6 showed higher values than the groups irradiated with Er:YAG and lower than the other groups. The other groups irradiated with Nd:YAG showed similar wear results to the control. Conclusions: The Er:YAG laser showed the lowest volume loss from wear analysis, suggesting the increased the acid resistance of dentin. Key words:Dentine sensitivity, Lasers, Sodium fluoride.

Influence of preventive remineralizing techniques on surface roughness and volume loss of dentin submitted to erosive and/or abrasive challenges.

Background: The objective this study was to evaluate the influence of preventive remineralizing techniques on surface roughness and volume loss of dentin submitted to erosive and/or abrasive challenges. Material and Methods: One hundred and eighty specimens of bovine root dentin were made; half of each was isolated (without treatment - WT) and half was subjected to the following remineralizing techniques: fluoride varnish (FV); Regenerate Boosting Serum® (RBS); Er,Cr:YSGG laser (L); fluoride varnish+laser (FV+L); Regenerate Boosting Serum®+laser (RBS+L). The specimens were submitted to erosive, abrasive and erosive followed by abrasive challenge. Erosion was carried out for 5 minutes, twice a day for 10 days. Abrasion was performed with an electric toothbrush and slurry solution for 60 seconds. The evaluation was performed by confocal laser scanning microscopy. Analysis of variance and Tukey tests were used for surface roughness; volume loss comparison was performed using the Kruskal-Wallis test and Dunn's post-hoc (p<0.05). Results: There was no statistically significant difference in the surface roughness of the reference area in relation to the areas submitted to different types of treatment and challenges (p>0.05). Regarding volume loss, the untreated group submitted to erosive/abrasive challenges showed greater percentage of volume loss compared to the other groups (p<0.05). Conclusions: It is concluded that preventive remineralizing techniques are effective in maintaining dentin volume after erosive/abrasive challenges. Key words:YSGG lasers, Dentin, Erosion, Tooth Abrasion.