Effects of different concentrations of sodium hypochlorite on dentine adhesion and the recovery application of sodium erythorbate / 中南大学学报(医学版)

OBJECTIVES@#Root canal therapy is the most effective and common method for pulpitis and periapical periodontitis. During the root canal preparation, chemical irrigation plays a key role. However, sodium hypochlorite (NaOCl), the widely used irrigation fluid, may impact the bonding strength between dentin and restorative material meanwhile sterilization and dissolving. Therefore, it's important to explore the influence of NaOCl on the adhesion between dentin and restoration materials to ensure clinical efficacy. This study aims to explore the effect of NaOCl on dentine adhesion and evaluate the effect of dentine adhesion induced by sodium erythorbate (ERY), and to provide clinical guidance on dentin bonding after root canal therapy.@*METHODS@#Seventy freshly complete extracted human third molars aged 18-33 years old, without caries and restorations were selected. A diamond saw was used under running water to achieve dentine fragments which were divided into 10 groups with 14 fragments in each group: 2 control [deionized water (DW)±10% ERY] and 8 experimental groups (0.5%, 1%, 2.5%, and 5.25% NaOCl±10% ERY). The dentine specimens in the control group (treated with DW) and the experimental groups (treated with 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl) were immersed for 20 min using corresponding solutions which were renewed every 5 min. The other 5 groups were immersed in 10% ERY for 5 min after an initial washing with DW for 1 min. Then, we selected 4 dentine fragments from all 14 fragments in each group and the numbers and diameters of opening dentinal tubules were observed under scanning electron microscope (SEM). The other 10 dentine fragments from each group were used to make adhesive samples by using self-etch adhesive wand composite resin. All the above adhesive samples were sectioned perpendicular to the bonded interface into 20 slabs with a cross-sectional area of 1 mm×1 mm using a diamond saw under the cooling water, and then the morphology of 10 slabs in each group's bonding interface was observed from aspects of formation of resin tags, depth of tags in dentin, and formation of hybrid layer under SEM. The other 10 slabs of each group's microtensile bond strength and failure modes were also analyzed.@*RESULTS@#Among the 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules gradually increased with the rise of concentration of NaOCl solution (all P<0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules increased after using ERY, but without significant difference (all P>0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, the scores of formation of resin tags under SEM gradually increased with the increase of concentration of NaOCl solution, while the score in the 5.25% NaOCl group decreased significantly compared with the score of the 2.5% NaOCl group (P<0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (all P>0.05). The scores of length of the tags under SEM in the 5.25% NaOCl group was significantly higher than the scores of DW, 0.5% NaOCl, and 1% NaOCl groups (all P<0.05), and it was also higher than the score of the 2.5% NaOCl group, but without significant difference (P>0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (P>0.05). The scores of formation of hybrid layer under SEM in the 2.5% NaOCl and 5.25% NaOCl groups significantly decreased compared with the score of the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). Microtensile bond strength was greater in the 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, but lower in the 5.25% NaOCl group than that in the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). The incidence of type "Adhesive" of failure modes in the 5.25% NaOCl group was significantly higher than that in other groups (all P<0.05), while the incidence of type "Adhesive" in the 5.25% NaOCl+10% ERY group was lower than that in the 5.25% NaOCl group (P<0.05).@*CONCLUSIONS@#The bonding strength to dentine increases with the increase of NaOCl concentration when the concentration lower than 2.5%; whereas it is decreased at a higher concentration (such as 5.25%). 10% ERY has a definite recovery effect on attenuated bonding strength to 5.25% NaOCl-treated dentine.

Humberto Fernández-Morán (1924-1999) a pioneer in electron ultra-cryomicroscopy / Humberto Fernández-Morán (1924-1999) pionero en ultracriomicroscopía electrónica

SUMMARY: Humberto Fernández-Morán (1924-1999) a Venezuelan physician and biophysicist research, who developed the diamond knife. Furthermore he focused on improving the mechanical performance, accuracy and reliability of mocrotomes and ultramicrotomes which significantly advanced the development of electromagnetic lenses for electron microscopy based on superconducting technology. Promoter and founded of the Venezuelan Institute for Neurological and Brain Studies. He was a pioneer in electron ultra-cryomicroscopy field. Fernández-Morán taught and researched in University of Stockholm, Massachusetts Institute of Technology, Harvard University, Massachussetts General Hospital and the University of Chicago. He worked with NASA for the Apollo project in the field of physic-chemical analysis of lunar rocks.

RESUMEN: Humberto Fernández-Morán (1924-1999) médico venezolano e investigador biofísico, quien desarrolló el cuchillo de diamante. Además, se centró en mejorar el rendimiento mecánico, la precisión y la fiabilidad de los micrótomos y ultramicrótomos, lo que avanzó significativamente en el desarrollo de lentes electromagnéticos para microscopía electrónica basados en tecnología superconductora. Promotor y fundador del Instituto Venezolano de Estudios Neurológicos y Cerebrales. Fue pionero en el campo de la ultracriomicroscopía electrónica. Fernández-Morán enseñó e investigó en la Universidad de Estocolmo, el Instituto Tecnológico de Massachusetts, la Universidad de Harvard, el Hospital General de Massachussets y la Universidad de Chicago. Trabajó con la NASA para el proyecto Apollo en el campo del análisis físico-químico de rocas lunares.

Effect of dlc films with and without silver nanoparticles deposited on titanium alloy

Abstract Diamond-like carbon (DLC) film is a biocompatible hard coating material that can prevent the leaching of metal ions. This study evaluates the structural characteristics of DLC, with and without silver nanoparticles, deposited by plasma (PECVD) on titanium alloy (Ti-6Al-4V) and bone formation in contact with DLC films. Sixty Ti-6Al-4V samples were used divided in: uncoated, coated with DLC and coated with DLC-Ag. After structural characterization, samples were fixed bilaterally at the rabbit's mandible. After 15 and 90 days, samples were characterized again and bone formation in the area was analyzed by histomorphometry. Statistical analysis was performed by two-way ANOVA. Both the DLC and DLC-Ag films were firmly adhered and showed a high electrical resistance without significant changes in the Raman spectrum after in vivo integration. After 15 days, there were immature bone trabeculae in the interface and partially covering the surface. After 90 days, mature bone filled the interface and coved the surface. There was no statistically significant difference among the three groups in both periods. In conclusion, osseointegration with DLC, DLC-Ag and uncoated Ti-6Al-4V is similar. However, DLC and DLC-Ag coverings have the advantage of electrical insulation and can presumably control bacterial activity and ion leaching.

Resumo O filme de carbono semelhante a diamante (DLC) é um material de revestimento duro e biocompatível que pode impedir a corrosão com liberação de íons metálicos. Este estudo avaliou as características estruturais do filme de DLC, com e sem nanopartículas de prata (Ag), depositadas por plasma (PECVD) em liga de titânio (Ti-6Al-4V) e formação óssea em contato com filmes de DLC. Foram utilizadas 60 amostras de Ti-6Al-4V divididas em: não recobertas, recobertas com DLC e recobertas com DLC-Ag. Após caracterização estrutural, amostras foram fixadas bilateralmente na mandíbula de coelhos. Após 15 e 90 dias, as amostras foram novamente caracterizadas e a formação óssea na área foi analisada por histomorfometria. A análise estatística foi realizada por ANOVA dois fatores. Ambos os filmes DLC e DLC-Ag foram firmemente aderidos e mostraram uma alta resistência elétrica sem alterações significativas no espectro Raman após a osseointegração in vivo. Após 15 dias, havia trabéculas ósseas imaturas na interface e cobrindo parcialmente a superfície. Após 90 dias, o osso maduro preencheu a interface e a superfície. Não houve diferença estatisticamente significante entre os três grupos nos dois períodos. Em conclusão, a osseointegração com DLC, DLC-Ag e Ti-6Al-4V não revestido é similar. No entanto, os revestimentos DLC e DLC-Ag têm a vantagem do isolamento elétrico e podem presumivelmente controlar a atividade bacteriana e a corrosão com liberação de íons.

Evaluation of the color stability of light cured composite resins according to the resin matrices / 대한치과재료학회지

The purpose of this study was to evaluate the color stability of light cured composite resins according to the resin matrices. Three kinds of resin matrices such as Bis-GMA (Venus® Diamond; VD), Silorane (FiltekTM P90; P90), and Ormocer (Admira; Ad) were selected. Each of them were used to prepare 30 specimens. The initial CIE L*a*b* values were measured by means of a Spectrophotometer (NF999, Nippon Denshoku, Japan). For accelerated aging process, the specimens were immersed in a circulating water bath with distilled water at 60℃. Spectrophotometric analyses were made after immersion of 8, 16, 24, 41 days and the color difference (ΔE*) was calculated. The L* value increased compared with initial L* value. VD had the greatest L* value change and Ad had the smallest L* value change (p<0.05). Ad had the greatest a* value change and VD had the smallest a* value change (p<0.05). The b* value of P90 increased steadily in positive value (+)(p<0.05). ΔE* of Ad had the smallest value and that of P90 had the greatest change with time. According to this study, the value of light cured composite resins was increased with water sorption and color of those changed into greenish and yellowish. And according to the evaluation of color stability, Ad with Ormocer as resin matrices had the best color stability with time in oral environment and P90 with Silorane as resin matrices had the lowest color stability with time. And VD had the greatest initial ΔE*.

Physical characteristics of ceramic/glass-polymer based CAD/CAM materials: Effect of finishing and polishing techniques

PURPOSE: The aim of this study was to compare the effect of different finishing and polishing techniques on water absorption, water solubility, and microhardness of ceramic or glass-polymer based computer-aided design and computer-aided manufacturing (CAD/CAM) materials following thermocycling. MATERIALS AND METHODS: 150 disc-shaped specimens were prepared from three different hybrid materials and divided into five subgroups according to the applied surface polishing techniques. All specimens were subjected up to #4000 grit SiC paper grinding. No additional polishing has been done to the control group (Group I). Other polishing procedures were as follows: Group II: two-stage diamond impregnated polishing discs; Group III: yellow colored rubber based silicone discs; Group IV: diamond polishing paste; and Group V: Aluminum oxide polishing discs. Subsequently, 5000-cycles of thermocycling were applied. The analyses were conducted after 24 hours, 7 days, and 30 days of water immersion. Water absorption and water solubility results were analyzed by two-way ANOVA and Tukey post-hoc tests. Besides, microhardness data were compared by Kruskal-Wallis and Mann-Whitney U tests (P.05). CONCLUSION: Surface finishing and polishing procedures might negatively affect physical properties of hybrid ceramic materials. Nevertheless, immersion periods do not affect the microhardness of the materials. Final polishing by using diamond polishing paste can be recommended for all CAD/CAM materials.

The effects of surface grinding and polishing on the phase transformation and flexural strength of zirconia

PURPOSE: The purpose of this in vitro study was to evaluate the effect of surface grinding and polishing procedures using high speed zirconia diamond burs with different grit sizes on the phase transformation and flexural strength of zirconia.

Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation

PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05). RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P < .001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

Influence of polishing systems on roughness and color change of two dental ceramics

PURPOSE: To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution.

A Literature Review of Research on Medical Service Design in Korea / 간호행정학회지

PURPOSE: Purpose of this study was to analyze research on the service design process applied to domestic medical service areas. METHODS: A review was made through domestic databases including RISS, KISS, DBpia, and NDSL and for the analysis framework: a medical service classification code which integrated the medical service area and the design fields. RESULTS: In the healthcare service field there were 9 studies (69.2%) in the medical area, 1 study (7.7%) each in nursing and oriental medicine, and 2 studies (15.4%) in healthcare. According to analysis results based on the medical service classification code, there were 5 studies in prevention and management, 6 studies in curative care, 1 each in rehabilitation and ancillary care. Double diamond process was used in 8 studies. CONCLUSION: Service design was applied mainly to the curative care in the domestic medical settings but little research on service design in the long-term nursing care area was identified. As a strategy to improve the quality of nursing service, it is necessary to adopt the service design process for various nursing service areas in Korea.

What is the changing frequency of diamond burs?

PURPOSE: The purpose of this study was to determine the changing frequency of a diamond bur after multiple usages on 3 different surfaces. MATERIALS AND METHODS: Human premolar teeth (N = 26), disc shaped direct metal laser sintered CoCr (N = 3) and zirconia specimens (N = 3) were used in this study. Groups named basically as Group T for teeth, Group M for CoCr, and Group Z for zirconia. Round tapered black-band diamond bur was used. The specimens were randomly divided into three groups and placed with a special assembly onto the surveyor. 1, 5, and 10 preparation protocols were performed to the first, second, and third sub-groups, respectively. The subgroups were named according to preparation numbers (1, 5, 10). The mentioned bur of each group was then used at another horizontal preparation on a new tooth sample. The same procedure was used for CoCr and zirconia disc specimens. All of the bur surfaces were evaluated using roughness analysis. Then, horizontal tooth preparation surfaces were examined under both stereomicroscope and SEM. The depth maps of tooth surfaces were also obtained from digital stereomicroscopic images. The results were statistically analyzed using One-Way ANOVA, and the Tukey HSD post-hoc tests (α=.05). RESULTS: All of the groups were significantly different from the control group (P < .001). There was no significant difference between groups Z5 and Z10 (P=.928). Significant differences were found among groups T5, M5, and Z5 (P < .001). CONCLUSION: Diamond burs wear after multiple use and they should be changed after 5 teeth preparations at most. A diamond bur should not be used for teeth preparation after try-in procedures of metal or zirconia substructures.

Effect of Surface Roughness on the Mechanical Properties of Ceramic-Polymer Blocks for CAD/CAM Dental Restoration / 대한치과재료학회지

The effect of surface roughness of ceramic-polymer CAD/CAM blocks on the mechanical properties was investigated in this study. Commercially available Polyglass (Vericom, Korea) and Enamic (Vita, Germany) were selected for this purpose. They were cut into either (4.0×2.1×17.0) mm and (3.0×4.0×17.0) mm, followed by grinding, and polished sequentially with 6 µm and 1 µm diamond paste. Flexural strength, fracture toughness, and Weibull analysis were determined according to ISO 6872 Dentistry-Ceramic materials. The elastic moduli were calculated from a stress-strain curves under flexural loading. The statistical significances of the mechanical properties between the products and surface roughness were analyzed with ANOVA and pared t-test at a significance level of 0.05. After grinding with 6 µm diamond paste after cutting by observing with an atomic force microscope, the arithmetic average roughness decreased to 47~49% and the maximum roughness decreased to 68~69%. When polishing with 1 µm diamond paste, The average roughness decreased to 13~22% and the maximum roughness decreased to 16~19%. When the flexural load was applied, stress increased linearly and fractured without plastic deformation both Polyglass and Enamic. As the surface roughness decreased, the mechanical properties were increased both Polyglass and Enamic. However, the mechanical properties of Polyglass increased up to P3, while Enamic showed almost maximal values at E2, after that there was no significant differences between E2 and E3. It could be due to the different microstructure between two blocks used in this experiment.

A Novel Porous Diamond - Titanium Biomaterial: Structure, Microstructure, Physico-Mechanical Properties and Biocompatibility

ABSTRACT With the aim of introducing permanent prostheses with main properties equivalent to cortical human bone, Ti-diamond composites were processed through powder metallurgy. Grade 1 titanium and mixtures of Ti powder with 2%, 5% and 10 wt% diamond were compacted at 100MPa, and then sintered at 1250°C/2hr/10-6mbar. Sintered samples were studied in the point of view of their microstructures, structures, yield strength and elastic modulus. The results showed that the best addition of diamonds was 2 wt%, which led to a uniform porosity, yield strength of 370MPa and elastic modulus of 13.9 GPa. Samples of Ti and Ti-2% diamond were subjected to in vitro cytotoxicity test, using cultures of VERO cells, and it resulted in a biocompatible and nontoxic composite material.

Analyses of Biofilm on Implant Abutment Surfaces Coating with Diamond-Like Carbon and Biocompatibility

Abstract The aim of this study was to evaluate the surface free energy (SFE), wetting and surface properties as well as antimicrobial, adhesion and biocompatibility properties of diamond-like carbon (DLC)-coated surfaces. In addition, the leakage of Escherichia coli through the abutment-dental implant interface was also calculated. SFE was calculated from contact angle values; R a was measured before and after DLC coating. Antimicrobial and adhesion properties against E. coli and cytotoxicity of DLC with human keratinocytes (HaCaT) were evaluated. Further, the ability of DLC-coated surfaces to prevent the migration of E. coli into the external hexagonal implant interface was also evaluated. A sterile technique was used for the semi-quantitative polymerase chain reaction (semi-quantitative PCR). The surfaces showed slight decreases in cell viability (p<0.05), while the SFE, R a, bacterial adhesion, antimicrobial, and bacterial infiltration tests showed no statistically significant differences (p>0.05). It was concluded that DLC was shown to be a biocompatible material with mild cytotoxicity that did not show changes in R a, SFE, bacterial adhesion or antimicrobial properties and did not inhibit the infiltration of E. coli into the abutment-dental implant interface.

Resumo O objetivo deste trabalho foi avaliar a energia livre de superfície (ELS), molhabilidade e propriedades de superfície assim como propriedades antimicrobianas, de adesão e biocompatibilidade de superfícies recobertas com Diamond-Like Carbon (DLC). Além disso, investigou-se a infiltração de Escherichia coli por meio da interface abutment-implante dentário. ELS foi calculada a partir dos valores de ângulo de contato; Ra foi medida antes e depois do revestimento com DLC. Foram avaliadas propriedades antimicrobianas e de adesão contra E. coli e citotoxicidade do DLC utilizando queratinócitos humanos (HaCaT). Além disso, também avaliamos a capacidade para impedir a migração de E. coli na interface do implante hexágono externo. Uma técnica estéril foi utilizada para a reação em cadeia da polimerase semi-quantitativa (PCR semi-quantitativo). As superfícies mostraram uma ligeira diminuição da viabilidade celular (p<0,05), enquanto a ELS, R a , adesão bacteriana, testes antimicrobianos e de infiltração não apresentaram diferenças estatisticamente significativas (p>0,05). Concluiu-se que o DLC demonstrou ser um material biocompatível levemente citotóxico que não mostra alterações na Ra , ELS, adesão bacteriana ou propriedades antimicrobianas e não inibiu a infiltração de E. coli na interface abutment-implante dentário.

CartoMerge using SoundStar Catheter and Time Force Integral-Based Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation is based on pulmonary vein (PV) isolation, but this procedure is thought to be demanding. The visualization of 3-dimensional information that is provided by CartoMerge® (BioSense Webster Inc., Diamond Bar, CA, USA) makes the ablation procedure easier. The SoundStar® catheter (BioSense Webster Inc., Diamond Bar, CA, USA)became available in Korea in September 2016. CartoMerge® using a SoundStar® catheter, which we termed as SoundMerge, is a simple way to obtain good CartoMerge® results. In addition, information on catheter stability and ablation intensity at each site are provided by a new ablation annotation system (CARTO® 3 System, VisiTag™ Module [BioSense Webster Inc., Diamond Bar, CA, USA]), which would be helpful for accomplishing durable PV isolation. In this article, we introduce the methodology of SoundMerge and the setting of the VisiTag™ module that we are performing currently. Effective practical use of these new technologies would improve the quality of ablation procedures.

Effect of grinding and heat treatment on the mechanical behavior of zirconia ceramic

Abstract The present study investigated the effect of grinding on roughness, flexural strength, and reliability of a zirconia ceramic before and after heat treatment. Seven groups were tested (n = 15): a control group (labeled CG, untreated), and six groups of samples ground with diamond discs, simulating diamond burs, with grits of 200 µm (G80); 160 µm (G120), and 25 µm (G600), either untreated or heat-treated at 1200°C for 2 h (labeled A). Yttria tetragonal zirconia polycrystal discs were manufactured, ground, and submitted to roughness and crystalline phase analyses before the biaxial flexural strength test. There was no correlation between roughness (Ra and Rz) and flexural strength. The reliability of the materials was not affected by grinding or heat treatment, but the characteristic strength was higher after abrasion with diamond discs, irrespective of grit size. The X-ray diffraction data showed that grinding leads to a higher monoclinic (m) phase content, whereas heat treatment produces reverse transformation, leading to a fraction of m-phase in ground samples similar to that observed in the control group. However, after heat treatment, only the G80A samples presented strength similar to that of the control group, while the other groups showed higher strength values. When zirconia pieces must be adjusted for clinical use, a smoother surface can be obtained by employing finer-grit diamond burs. Moreover, when the amount of monoclinic phase is related to the degradation of zirconia, the laboratory heat treatment of ground pieces is indicated for the reverse transformation of zirconia crystals.

The effect of standardised implantoplasty protocol on titanium surface roughness: an in-vitro study

Abstract: To analyse the changes of surface characteristics of machined and moderately roughened titanium disks following a standardised implantoplasty protocol. Forty titanium discs (machined: n = 20; moderately roughened: n = 20) were instrumented with one half of each disc maintained as the control (non-instrumented). The standardised implantoplasty protocol was carried out using a custom jig with the sequential change of burs: 1) Regular grit diamond [10s], 2) Super-fine grit diamond [10s], 3) Brownie(tm) silicone polisher [15s], 4) Greenie(tm) silicone polisher [15s]. Surface topography was analysed using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Energy dispersive x-ray spectroscopy (EDS) was used to measure the elemental profiles of each disc. Quantitative analysis showed similar changes in level of roughness between the machined and moderately roughened titanium discs. CLSM demonstrated an increased roughness (Ra and Sa values) after polishing with a regular grit diamond bur when compared to the uninstrumented surfaces. Although the roughness decreased after the further polishing with the super-fine grit diamond bur, subsequent instrumentation using silicon burs tended to increase the roughness, albeit being statistically insignificant. There was a residue of silicon particles despite the irrigation after each polishing stage. The proposed implantoplasty protocol did not achieve a sufficient level of smoothness on the machined or moderately roughened titanium surfaces when compared to the Ra threshold. Further research is recommended to test the efficacy of each bur on titanium surfaces with longer duration using actual oral implants to allow better comparison.

Effect of dentin surface roughness on the shear bond strength of resin bonded restorations

PURPOSE: This study aimed to investigate whether dentin surface preparation with diamond rotary instruments of different grit sizes affects the shear bond strength of resin-bonded restorations. MATERIALS AND METHODS: The buccal enamel of 60 maxillary central incisors was removed with a low speed diamond saw and wet ground with silicon carbide papers. The polished surfaces of the teeth were prepared with four groups of rotary diamond burs with super-coarse (SC), coarse (C), medium (M), and fine (F) grit sizes. Following surface preparation, 60 restorations were casted with nickel-chromium alloy and bonded with Panavia cement. To assess the shear bond strength, the samples were mounted on a universal testing machine and an axial load was applied along the cement-restoration interface at the crosshead speed of 0.5 mm/min. The acquired data was analyzed with one way ANOVA and Tukey post hoc test (α=.05). RESULTS: The mean ± SD shear bond strengths (in MPa) of the study groups were 17.75 ± 1.41 for SC, 13.82 ± 1.13 for C, 10.40 ± 1.45 for M, and 7.13 ± 1.18 for F. Statistical analysis revealed the significant difference among the study groups such that the value for group SC was significantly higher than that for group F (P<.001). CONCLUSION: Dentin surface roughness created by diamond burs of different grit sizes considerably influences the shear bond strength of resin bonded restorations.

Recomendações e práticas dos comportamentos saudáveis entre indivíduos com diagnóstico de hipertensão arterial e diabetes no Brasil: Pesquisa Nacional de Saúde (PNS), 2013 / Recommendations and practice of healthy behaviors among patients with diagnosis and diabetes in Brazil: National Health Survey (PNS), 2013

Resumo: Objetivo: Analisar as recomendações relacionadas aos comportamentos saudáveis e a adoção das práticas recomendadas entre indivíduos hipertensos e diabéticos. Métodos: Foram analisadas recomendações relacionadas aos comportamentos saudáveis segundo local do último atendimento (atenção básica; outros estabelecimentos públicos; estabelecimentos do setor privado). Os efeitos de ter um diagnóstico de hipertensão ou diabetes sobre a adoção das práticas recomendadas foram analisados por modelos de regressão logística multivariada, usando sexo, idade, e grau de escolaridade como variáveis de controle, e os seguintes desfechos: uso atual de produtos de tabaco; prática regular de atividade física no lazer; consumo recomendado de hortaliças e frutas; percepção de baixo consumo de sal; consumo frequente de doces; consumo excessivo de álcool. Resultados: Aproximadamente, 88% dos hipertensos receberam recomendações de ter uma alimentação saudável, 91% de ingerir menos sal, 83% de praticar atividade física regular, e 76% de não fumar. Entre os diabéticos, todas as recomendações relacionadas à alimentação foram muito frequentes, 95% para o hábito de ter uma alimentação com frutas e hortaliças. O efeito de ter um diagnóstico de hipertensão foi significativo para o não uso de produtos de tabaco e percepção de baixo consumo de sal. O diagnóstico de diabetes influenciou principalmente o hábito de não consumir doces frequentemente. Conclusão: Evidenciou-se que os hipertensos e diabéticos dão prioridade a não usar hábitos nocivos à saúde do que adotar práticas que lhe trarão benefícios. É preciso promover não só os efeitos adversos dos hábitos nocivos, mas também os benefícios dos comportamentos saudáveis para o envelhecimento com qualidade.

Abstract: Objective: To analyze healthy life style recommendations given in health care and the adoption of healthy behaviors among hypertension and diabetes patients. Methods: We analyzed the recommendations according to the place of the last health care visit (primary health care, other public facilities, and private health care facilities). The effects of having a diagnosis of hypertension or diabetes on the adoption of healthy practices were analyzed by multivariate logistic regression models, using sex, age, and educational level as control variables, and the following outcomes: current use of tobacco products; regular physical activity during leisure time; recommended intake of fruits and vegetables; perception of low salt intake; frequent consumption of sweets; and excessive alcohol consumption. Results: Approximately 88% of hypertension patients received recommendations to have a healthy diet, 91% to eat less salt, 83% to practice regular physical activity, and 76% to not to smoke. Among diabetic patients, all recommendations related to nutrition were very frequent, reaching 95% for the habit of having fruits and vegetables regularly. The effect of having a diagnosis of hypertension was significant for non-use of tobacco products and perception of low salt intake. The diagnosis of diabetes mainly influenced the habit of not consuming sweets often. Conclusion: Results evidenced that people with diagnosis of hypertension and diabetes give priority to not use (stop) harmful health behaviors than to adopt practices that will bring benefits to their health. It is necessary to promote not only the adverse effects of harmful habits, but also the benefits of healthy behaviors to aging well.

Efficiency of different protocols for enamel clean-up after bracket debonding: an in vitro study

Objective: This study aimed to assess the efficiency of six protocols for cleaning-up tooth enamel after bracket debonding.Methods:A total of 60 premolars were divided into six groups, according to the tools used for clean-up: 12-blade bur at low speed (G12L), 12-blade bur at high speed (G12H), 30-blade bur at low speed (G30L), DU10CO ORTHO polisher (GDU), Renew System (GR) and Diagloss polisher (GD). Mean roughness (Ra) and mean roughness depth (Rz) of enamel surface were analyzed with a profilometer. Paired t-test was used to assess Ra and Rz before and after enamel clean-up. ANOVA/Tukey tests were used for intergroup comparison. The duration of removal procedures was recorded. The association between time and variation in enamel roughness (∆Ra, ∆Rz) were evaluated by Pearson's correlation test. Enamel topography was assessed by scanning electron microscopy (SEM).Results:In Groups G12L and G12H, original enamel roughness did not change significantly. In Groups G30L, GDU, GR and GD, a smoother surface (p < 0.05) was found after clean-up. In Groups G30L and GD, the protocols used were more time-consuming than those used in the other groups. Negative and moderate correlation was observed between time and (∆Ra, ∆Rz); Ra and (∆Ra, ∆Rz); Rz (r = - 0.445, r = - 0.475, p < 0.01).Conclusion:All enamel clean-up protocols were efficient because they did not result in increased surface roughness. The longer the time spent performing the protocol, the lower the surface roughness.

Objetivo: esse estudo objetivou avaliar a eficiência de seis protocolos de remoção de resina do esmalte após a descolagem de braquetes.Métodos:sessenta (60) pré-molares foram divididos em seis grupos conforme as ferramentas utilizadas: broca de 12 lâminas em baixa rotação (G12L), broca de 12 lâminas em alta rotação (G12H), broca de 30 lâminas em baixa rotação (G30L), polidor DU10CO-ORTHO (GDU), Renew System (GR) e polidor Diagloss (GD). As médias de rugosidade (Ra) e profundidade média de rugosidade (Rz) da superfície do esmalte foram analisadas com perfilômetro. Teste t pareado foi utilizado para avaliar Ra e Rz antes e depois da limpeza do esmalte; testes de ANOVA/Tukey foram utilizados para avaliar a diferença intergrupos. A duração dos procedimentos de remoção da resina foi registrada. Ainda, a associação entre o tempo e a variação da rugosidade do esmalte (ΔRa, ΔRz) foi avaliada pelo teste de correlação de Pearson. A topografia do esmalte também foi avaliada, por microscopia eletrônica de varredura (MEV).Resultados:nos grupos G12L e G12H, a rugosidade do esmalte original não se alterou significativamente. Nos Grupos G30L, GDU, GR e GD, foi verificada superfície mais lisa após a limpeza (p< 0,05). Nos Grupos G30L e GD, os protocolos utilizados foram mais demorados que nos demais grupos. Foi observada correlação negativa e moderada entre tempo, ΔRa e ΔRz (r = -0.445, r = -0.475, p< 0,01).Conclusão:todos os protocolos de limpeza do esmalte foram eficientes, pois não resultaram no aumento da rugosidade superficial. Quanto maior o tempo gasto, menor a rugosidade da superfície.

Loosening torque of Universal Abutment screws after cyclic loading: influence of tightening technique and screw coating

PURPOSE: The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS: Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at 106 cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). RESULTS: The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). CONCLUSION: The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.