Alma Blásida Concepción Elizaur Benitez Catirse

Objetivo: Comparar ex vivo la eficacia de los sistemas rotatorios Neolix-NeoNiti y ProTaper Next en la desobturación y reconformación de conductos radiculares de raíces palatinas de primeros molares superiores durante el retratamiento endodóntico, incluyendo como referencia basal la calidad de la obturación de primera intención previa al retratamiento. Material y Métodos: Estudio experimental ex vivo, comparativo. De un banco de 80 molares superiores se conformó una muestra de 40 piezas maduras apicalmente con raíz palatina completa, tratadas endodónticamente de primera intención y distribuidas aleatoriamente en dos grupos de 20: Grupo 1, retratado con Neolix-NeoNiti (Francia), y Grupo 2, con ProTaper Next (Dentsply Maillefer, Suiza). En los tercios cervical, medio y apical de la raíz palatina se evaluó la presencia de restos de obturación, la transportación/desviación y la fractura de instrumentos mediante tomografía computarizada (TC), radiovisiografía digital (RVG) y microscopía operatoria Newton de 16 a 125 aumentos. Se aplicaron chi-cuadrado, prueba exacta de Fisher y ANOVA factorial (p0,05), pero sí entre tercios, con mayor incidencia de restos en el tercio apical (22,5%) que en el cervical (7,5%) y el medio (2,5%) (p=0,011). La RVG mostró mayor incidencia de restos con ProTaper Next en el tercio medio (20,0% vs. 0,0% con Neolix; p=0,035) y mayor transportación apical con ProTaper Next (25,0% vs. 10,0% con Neolix; total 11,7% vs. 3,3%). La fractura instrumental fue infrecuente y sin diferencias significativas entre grupos (Neolix 6,7%, ProTaper Next 3,3%; total 5,0%; p>0,05).

This study evaluated the effects of brushing with desensitizing and anti-erosive toothpastes on the chemical composition and morphology of eroded dentin. Four groups were tested: Colgate Sensitive Pro-Relief® (ARG), Sensodyne Repair and Protect® (CSPS), Regenerate Enamel Sci-ence® (REG) and a control (Colgate Total®). Particle size, zeta potential, dentin surface charge, chemical composition, and tubule occlusion were assessed using dynamic light scattering (DLS), ATR-FTIR, and SEM-EDS measurements. All toothpastes contained nanosized particles with diameters ranging from 86 to 597 nm and exhibited negative zeta potentials from -25.3 to −45.0 mV. Eroded dentin initially exhibited a higher Ca/P molar ratio than hydroxyapatite, indicating Ca2+ deficiency, which was restored to near-stoichiometric values (1.67) after brushing. Brushing preserved the chemical composition of dentin, as confirmed by infrared spectroscopy, which exhibited bands assigned to phosphate, carbonate, and collagen. Morphologically, all tested toothpastes significantly reduced dentinal tubule diameter compared with the unbrushed control (3.44 ± 0.57 μm). The CSPS group exhibited the most effective occlusion with a final tubule di-ameter of 1.00 ± 0.24 μm and deposit penetration of 22.6 μm, maintaining significant occlusion and penetration even after acid exposure (1.10 ± 0.28 μm and 20.8 μm, respectively). The REG group showed good initial occlusion with a tubule diameter of 1.21 ± 0.33 μm and the deepest penetration (25.0 μm). Still, it exhibited lower acid resistance, characterized by an increased tubule diameter (1.61 ± 0.40 μm) and a reduced penetration depth (10.0 μm). ARG presented intermediate occlusion with a tubule diameter of 1.49 ± 0.48 μm and penetration depth of 13.7 μm, along with good acid resistance (1.78 ± 0.57 μm diameter; 11.5 μm depth). The dentin brushed with the control group also maintained tubule occlusion before and after acid exposure (1.55 ± 0.50 μm and 1.55 ± 0.48 μm, respectively), showing high initial penetration (26.2 μm), but the lowest post-acid penetration depth (5.26 μm). In conclusion, a nanometric particle size and a slight negative charge are critical for coating deposition and tubule penetration. The for-mation of mineral coatings preserves the chemical composition of dentin and may offer a protective barrier against acidic challenges. Sensodyne Repair and Protect® exhibits the most consistent tubule occlusion after acid exposure, suggesting a potential for enhanced acid resistance. Among the tested formulations, CSPS exhibited the most consistent tubule occlusion after acid exposure, suggesting a potential for enhanced acid resistance.

Aim: Evaluate the roughness, microhardness and color change of different Bulk Fill resins when submitted to the condition of gastroesophageal reflux and bulimia. Methods: 60 specimens (n = 10) of Bulk-Fill composite resins were made: M1 – Filtek™; M2 – Tetric N-Ceram and M3 – OPUS, through a matrix 2x6 mm and light cured by the VALO light source. After polishing, initial analyzes (48 hours - T0) of surface roughness (Ra), microhardness (VHN) and color change (ΔE) were performed. To simulate the oral condition of severe gastroesophageal reflux and bulimia, the specimens were immersed in hydrochloric acid (S1) (pH 1.7) 4 minutes a day, for 7 days. Control group specimens were immersed in artificial saliva (S2). Subsequently to immersions, mechanical brushing was performed for 3 minutes, three times a day, simulating 7 days of brushing. And again, the analyzes of Ra, VHN and ΔE were performed (7 days - T1). Thus, hydrochloric acid immersion, mechanical brushing and Ra analysis were repeated at 14 days (T2) and 21 days (T3); and T2, T3 and T4 (3 years) for VHN and ΔE. Results: After Shapiro-Wilk statistical test, ANOVA and Tukey test with Bonferroni adjustment (p>0.05), M3 showed the lowest Ra at all times compared to the other resins, while the highest Ra was at T0. M1 and T1 showed higher VHN. And M2 and T4 showed higher ΔE. Conclusion: Bulk Fill resins can be indicated for patients with Gastroesophageal Reflux and Bulimia, nonetheless, Tetric N-Ceram resin showed the worst results.

Strontium acetate is applied for dental hypersensitivity treatment; however, the use of strontium carbonates for this purpose has not been described. The use of Sr-carbonate nanoparticles takes advantage of both the benefits of strontium on dentin mineralization and the abrasive properties of carbonates. Here in, we aimed to synthesize strontium carbonate and strontium-substituted calcium carbonate nanoparticles and test them as potential compounds in active dentifrices for treating dental hypersensitivity. For this, SrCO₃, Sr_0.5Ca_0.5CO₃, and CaCO₃ nanoparticles were precipitated using Na₂CO₃, SrCl₂, and/or CaCl₂ as precursors. Their morphology and crystallinity were evaluated by electron microscopy (SEM) and X-ray diffraction, respectively. The nanoparticles were added to a poly (vinyl alcohol) gel and used to brush dentin surfaces isolated from human third molars. Dentin chemical composition before and after brushing was investigated by infrared spectroscopy (FTIR) and X-ray dispersive energy spectroscopy. Dentin tubule morphology, obliteration, and resistance of the coatings to acid attack were investigated by SEM and EDS. The cytotoxicity and ability of the particles to trigger the mineralization of hDPSCs in vitro were studied. Dentin brushed with the nanoparticles was coated by a mineral layer that was also able to penetrate the tubules, while CaCO₃ remained as individual particles on the surface. FTIR bands related to carbonate groups were intensified after brushing with either SrCO₃ or Sr_0.5Ca_0.5CO₃. The shift of the phosphate-related FTIR band to a lower wavenumber indicated that strontium replaced calcium on the dentin structure after treatment. The coating promoted by SrCO₃ or Sr_0.5Ca_0.5CO₃ resisted the acid attack, while calcium and phosphorus were removed from the top of the dentin surface. The nanoparticles were not toxic to hDPSCs and elicited mineralization of the cells, as revealed by increased mineral nodule formation and enhanced expression of COL1, ALP, and RUNX2. Adding Sr_0.5Ca_0.5CO₃ as an active ingredient in dentifrices formulations may be commercially advantageous since this compound combines the well-known abrasive properties of calcium carbonate with the mineralization ability of strontium, while the final cost remains between the cost of CaCO₃ and SrCO₃. The novel Sr_0.5Ca_0.5CO₃ nanoparticles might emerge as an alternative for the treatment of dental hypersensitivity.

Aim: This study aims to evaluate the surface roughness and susceptibility to staining of bleached composite resin with 22% carbamide peroxide, as well as the effect of subsequent prophylaxis with NaHCO3 powder. Material and Methods: Forty disk-shaped (2 × 6 mm) specimens of composite resin (Z250 XT) were prepared. Half of the specimens were subjected to bleaching with 22% carbamide peroxide, and the other half were stored in artificial saliva. In sequence, all specimens were immersed in acai juice (Euterpe oleracea) for 4 h for 14 days, and subdivided into two groups. Group 1 samples were subjected to prophylaxis treatment, while group 2 samples were subjected to treatment with artificial saliva. Surface roughness (Ra) and color (ΔE*) were measured after polishing (T0), bleaching (T1), immersion in acai juice (T2), and application of NaHCO3 powder (T3) using a profilometer and a spectrophotometer. Results: Statistical analyses (analysis of variance and Tukey's test, p≤0.05) revealed that regarding color there was statistically significance for the factors in isolation, except for the factor bleaching. For both color and surface roughness there was statistically significant difference for the interaction, except for the interaction between NaHCO3 power and bleaching. Conclusion: The NaHCO3 air-powder polishing decreases the staining of the composite resin; however, it increases the surface roughness. With respect to the color variable, the whitening factor had no significant effect on the tested material; however, it increases surface roughness.

Objective: Use fluorescence analysis to evaluate the effect of polishing and surface sealant on the color of composite resin bleached with carbamide peroxide and subjected to staining.Materials and methods: Forty‐eight composite resin specimens (Z250/Z350XT) were fabricated. After 24 hours stored in distilled water, all specimens were submitted to in situ bleaching with 16% home peroxide for 8 hours daily for a period of 14 days. Subsequently specimens were separated in three groups according to surface treatment proposed (group 1—polishing Sof‐Lex; group 2—BisCover; group 3—control). After this, all the specimens were stained with red wine. A spectrofluorometer was used to evaluate the fluorescence in two readouts (L0—after surface treatment and L1—after staining).Data were analyzed by applying ANOVA using a statistical software program.Results: No differences were shown for the factor treatment and other interactions. The lowest mean fluorescence value was found for Z350XT resin (1759.18 ± 0.13) when compared with Z250 (6863.92 ± 0.13). There was significant difference in the mean fluorescence values for all surface treatments between the two different readouts L0 (4820.93 ± 0.05) and L1 (3802.17 ± 0.05).Conclusion: The results suggested that all surface treatments proposed did not influenced the results of wine staining of bleached resins when compared with the control evaluated by the fluorescence method.Clinical significance: The purposes of this research was to find solutions, by means of surfaces treatment, to achieve restorations with a satisfactory and similar final aspect in relation to the teeth, and avoid discrepancies related to the esthetics and longevity of the restoration.

Objective: evaluate the bond strength of resin cements to new materials for application in intraradicular posts. Material and Methods: Five materials were evaluated: fiberglass, PET, polyethylene, polyacetal and PTFE. Two commercial resin cements (Rely X U200 and Rely X Arc) were applied on the test specimens of the materials (9x3mm) and the bonding was evaluated through the shear bond strength test, where the chisel operated with a load of 1kN and a velocity of 0.5mm/min at the cement/material interface. The data were analyzed by the Shapiro-Wilk test, followed by the two-way analysis of variance, performed with the Bonferroni post-test (?=0.05). Results: The glass fiber was statistically different from all evaluated materials (p0.05). Comparing the two cements, a statistical difference was found between Rely X U200 and Arc only for the glass fiber (p=0). Conclusion: PET, polyethylene, polyacetal and PTFE exhibited reduced bond strength compared to the glass fiber.KeywordsResin cement; PET polymer; Polytetrafluoroethylene.

Este artigo analisa a formação de professores universitários, no contexto da pesquisa Curso Pedagogia Universitária: os professores e sua prática pedagógica desenvolvida pelo Grupo de Apoio Pedagógico do Campus USP-Ribeirão Preto/Universidade de São Paulo – Brasil – (GAPRP). Trata de pesquisa descritivo-exploratória, de natureza qualitativa que se propõe a analisar as reflexões de professores, participantes do I e II Curso de Pedagogia Universitária realizado em Ribeirão Preto em 2008 e 2009, acerca de sua prática pedagógica. Os dados revelam que as reflexões desses professores contemplam a revisitação de suas práticas pedagógicas, os limites contextuais e administrativos e a gestão do projeto político pedagógico com possibilidades de mudanças. Evidenciam-se também alguns pontos de tensão que necessitam ser trabalhados: aprendizagem da docência como perspectiva individual versus docência como perspectiva coletiva; formação pedagógica como prática sócio-política versus prática instrumental e valorização da pesquisa em detrimento do ensino.

University pedagogy has been promoted in the context of the policy for valuing undergraduate training at the University of São Paulo (USP). In this regard, one action of the Undergraduate Pro-Rectory was the creation of pedagogic support groups. The objective of this study is to report and analyze the strategies for university teacher training developed by the Pedagogic Support Group at the Ribeirão Preto Campus (GAPRP/USP–Grupo de Apoio Pedagógico do Campus de Ribeirão Preto), during the period from 2002 to 2015. The group takes on a conception of teacher training that extrapolates the technical dimension, considering political-social and historical determinants that have shaped the university, undergraduate teaching, and the faculty, as well as the valorization of strategies promoting reflection, theoretical-practical articulation, and collective learning. During the day-to-day monitoring of these education strategies, a few aspects are highlighted and analyzed: identification of the need for pedagogic training as an individual initiative of the teaching staff, despite the policies for valuing undergraduate training; investment in continuous educational strategies and the education undergone by the faculty that compose GAPRP/USP. To conclude, teacher training means to value the construction of a political project so as to qualify university teachers.

Objective: To evaluate the surface roughness of resin composite and ceramic material after immersion in mouthwashes. Methodology: Thirty specimens of resin composite and ceramic material were prepared with a stainless steel matrix (6 mm × 2 mm). The samples of each material were divided into three groups (n = 10), according to the mouthwashes: Distilled water (DW), chlorhexidine (CL) 0.12%, and cetylpyridinium chloride (CC). Specimens were individually submitted to the immersion cycle in 15 mL of mouthwash for 30 days, three times per day, for 1 min/cycle. Surface roughness measurements were performed at three different time intervals: Before the first cycle (T0), after 7 (T1), and 30 days (T2) of immersion. Data were analyzed by the two-way ANOVA and Tukey tests (P ≤ 0.05). Results: There was no statistically significant difference in surface roughness of resin composite among mouthwashes (DW - 1.4 ± 0.13 μm; CL - 1.16 ± 0.13 μm; CC - 1.18 ± 0.13 μm). Surface roughness was statistically significantly lower after 30 days (T2-0.56 ± 0.60 μm) compared with the initial period (T0-1.63 ± 0.60 μm) and after 7 days (T1-1.57 ± 0.60 μm). For ceramic material, CC (3.75 ± 0.60 μm) caused a higher level of surface roughness compared with DW (2.57 ± 0.60 μm) and CL (3.39 ± 0.60 μm). There was no statistically significant difference among the different time intervals (T0-3.05 ± 0.18 μm; T1-3.41 ± 0.18 μm; T2-3.26 ± 0.18 μm). Conclusion: Mouthwashes did not promote a significant change in surface roughness of composite resin. Cetylpyridinium chloride promoted an increase in surface roughness of dental ceramic.