Evaluation of dentin microroughness and composite bond strength after multiple uses of diamond burs / Evaluación de la micro rugosidad dentinaria y la resistencia adhesiva de composites tras múltiples usos de fresas de diamante

Abstract Using a bur multiple times to prepare dental structure may produce a smoother final surface on dentin than a new one. This superficial roughness may affect adhesion with resin-based materials by modifying the substrates' characteristics. The aim of this study was to evaluate the effect of multiple uses of diamond burs on dentin's superficial microroughness and bond strength with resin composite when using a self-etch adhesive. Diamond dental burs were used to simulate a preparation (dentin flat surface) on extracted third molars. Samples were distributed into groups according to burs' number of previous uses as follows: 0, 1, 5 and 10. Scanning electron microscopy images at 70x, 350x, and 1000x were used to illustrate burs' deformation. Each specimen's dentin microroughness was measured three times to compare between experimental groups and the micro-shear bond strength test (n=15) was performed for the 0 and 10 uses groups using a universal adhesive in a self- etching mode. Diamond crystals wear and dislodgements were evident among groups where the burs were used more times. As the number of uses increased the mean microroughness of the dentin surface decreased with significant differences between the 0 and 10 uses groups. No statistical differences between experimental groups resulted from bond strength tests. When using a universal adhesive in a self-etching mode, the number of previous uses of a diamond bur seems to have no significant effect on dentin/resin composite bond strength.

Resumen El uso de una fresa múltiples veces para preparar la estructura dental puede producir una superficie final más lisa en la dentina que una fresa nueva. Esta rugosidad superficial modifica las características del sustrato y puede afectar la adhesión con materiales resinosos. El objetivo de este estudio fue evaluar el efecto de los múltiples usos de las fresas de diamante sobre la micro rugosidad superficial de la dentina y la resistencia adhesiva con la resina compuesta cuando se utiliza un adhesivo de autograbado. Se utilizaron fresas dentales de diamante para simular una preparación (superficie plana de la dentina) en terceros molares extraídos. Las muestras se distribuyeron en grupos según el número de usos previos de las fresas de la siguiente manera: 0, 1, 5 y 10. Se utilizaron imágenes de microscopía electrónica de barrido a ×70, ×350 y ×1000 para ilustrar la deformación de las fresas. Se midió la micro rugosidad de la dentina de cada espécimen tres veces para comparar entre los grupos experimentales y se realizó la prueba de resistencia a la adhesión por micro cizallamiento (n=15) para los grupos de 0 y 10 usos utilizando un adhesivo universal en modo de autograbado. El desgaste de los cristales de diamante y los desprendimientos fueron evidentes entre los grupos en los que las fresas se utilizaron más veces. A medida que aumentaba el número de usos, la micro rugosidad media de la superficie de la dentina disminuyó, con diferencias significativas entre los grupos de 0 y 10 usos. En las pruebas de resistencia adhesiva no se observaron diferencias estadísticas entre los grupos experimentales. Cuando se utiliza un adhesivo universal en modo de autograbado, el número de usos previos de una fresa de diamante no parece tener un efecto significativo en la resistencia de la unión dentina/resina del composite.

Nanoporous Titanium Enriched with Calcium and Phosphorus Promotes Human Oral Osteoblast Bioactivity.

Implant surfaces are known to influence the osseointegration process; therefore, their modifications represent an important subject of investigation. On this basis, the purpose of this study was to evaluate the response of human oral osteoblasts (hOBs) to three different GR4 titanium discs: Machined, double-etched (Osteopore), and double-etched, surface-enriched with calcium and phosphorus (CaP) (Nanopore). The superficial topography was investigated with scanning electron microscopy (SEM) and the sessile drop technique. To test cellular response and osteoinductive properties, the following points were evaluated: (i) proliferation by MTS assay after 2 and 5 days; (ii) adhesion by multiphoton microscopy at day 2; (iii) the interaction with Ti discs by blue toluidine staining at day 5; (iv) alkaline phosphatase (ALP) activity by ALP assay after 14 days; (v) calcium deposition by alizarin red staining and by cetylpyridinium chloride after 14 days. The SEM analysis showed that Nanopore and Osteopore surfaces were characterized by the same micro-topography. Nanopore and Osteopore discs, compared to Machined, stimulated higher osteoblast proliferation and showed more osteoinductive properties by promoting the ALP activity and calcium deposition. In conclusion, the CaP treatment on DAE surfaces seemed to favor the oral osteoblast response, encouraging their use for in vivo applications.

Surface Characteristics of High Translucent Multilayered Dental Zirconia Related to Aging.

(1) Background: The purpose of this study was to evaluate the differences in terms of surface characteristics (roughness, topography, microhardness) among layers for multi-layered high translucent and super-high translucent zirconia and the influence of finishing and aging on surface characteristics and microstructure. (2) Methods: Three types of translucent multilayer zirconia were evaluated: STML (4Y-TZP); IPS e.maxZirCAD CEREC/in Lab MT Multi (4Y-TZP + 5Y-TZP); CeramillZolidfx ML (5Y-TZP). Ninety-six plate-shaped samples (32 for a material), 16 mm × 14 mm × 1 mm size, were cut with a precision disc, polished on both sides with sand papers and sintered respecting the manufacturer's protocol. Half of the specimens (16) were finished by polishing and the other half by glazing and then equally divided into one control group and one group subject to aging by autoclaving (1 h, 134 °C, 0.2 MPa), resulting in four groups of eight samples, for each zirconia. The specimens were evaluated in three areas: cervical, medium, incisal-of each glazed or polished surface, before and after aging. Tests were performed to determine the surface roughness using a profilometer; the surface topography by an atomic force microscope (AFM) and a scanning electron microscope (SEM). Microhardness was recorded using a microhardness tester. Statistical analyses were performed using two-way ANOVA test, unpaired sample t-Test, paired sample t-Test (α = 0.05) and Pearson's correlation. (3) Results: Before and after autoclaving, for glazed samples significance (p < 0.05) higher surface roughness, respectively lower microhardness in comparison with the polished group was assessed. No significant differences (p > 0.05) were reported between the three areas, on glazed or polished surfaces of a material. Although, after aging an increase in surface roughness was observed both on glazed and polished samples, statistical differences were found for STML (p < 0.05). No significant differences (p> 0.05) concerning microhardness among the same areas, on glazed and polished surfaces, recorded before and after aging, except CeramillZolidfx ML glazed samples. (4) Conclusions: For tested zirconia materials no significant differences among layers were registered regarding surface characteristics. Surface treatment (glazing or polishing) has a significant impact on surface roughness and microhardness. Both before and after aging, the surface roughness values for the glazed samples were higher than for those polished. The super translucent 4Y-TZP material was more affected by aging compared to the super-high translucent 5Y-TZP material. The combined material revealed similarities for each layer corresponding to the microstructure.

The effects of controlled nanotopography, machined topography and their combination on molecular activities, bone formation and biomechanical stability during osseointegration.

The initial cellular and molecular activities at the bone interface of implants with controlled nanoscale topography and microscale roughness have previously been reported. However, the effects of such surface modifications on the development of osseointegration have not yet been determined. This study investigated the molecular events and the histological and biomechanical development of the bone interface in implants with nanoscale topography, microscale roughness or a combination of both. Polished and machined titanium implants with and without controlled nanopatterning (75 nm protrusions) were produced using colloidal lithography and coated with a thin titanium layer to unify the chemistry. The implants were inserted in rat tibiae and subjected to removal torque (RTQ) measurements, molecular analyses and histological analyses after 6, 21 and 28 days. The results showed that nanotopography superimposed on microrough, machined, surfaces promoted an early increase in RTQ and hence produced greater implant stability at 6 and 21 days. Two-way MANOVA revealed that the increased RTQ was influenced by microscale roughness and the combination of nanoscale and microscale topographies. Furthermore, increased bone-implant contact (BIC) was observed with the combined nanopatterned machined surface, although MANOVA results implied that the increased BIC was mainly dependent on microscale roughness. At the molecular level, the nanotopography, per se, and in synergy with microscale roughness, downregulated the expression of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In conclusion, controlled nanotopography superimposed on microrough machined implants promoted implant stability during osseointegration. Nanoscale-driven mechanisms may involve attenuation of the inflammatory response at the titanium implant site. STATEMENT OF SIGNIFICANCE: The role of combined implant microscale and nanotopography features for osseointegration is incompletely understood. Using colloidal lithography technique, we created an ordered nanotopography pattern superimposed on screwshaped implants with microscale topography. The midterm and late molecular, bone-implant contact and removal torque responses were analysed in vivo. Nanotopography superimposed on microrough, machined, surfaces promoted the implant stability, influenced by microscale topography and the combination of nanoscale and microscale topographies. Increased bone-implant contact was mainly dependent on microscale roughness whereas the nanotopography, per se, and in synergy with microscale roughness, attenuated the proinflammatory tumor necrosis factor alpha (TNF-α) expression. It is concluded that microscale and nanopatterns provide individual as well as synergistic effects on molecular, morphological and biomechanical implant-tissue processes in vivo.

Hybrid membrane with controllable surface microroughness by micro-nano structure processing for diluted PM2.5 capture.

Tremendous efforts have been devoted by researchers on air particulate matter pollution for the increasing harm, however, the Air Pollution Index (API) from "good" to "excellent" is something hard to achieve. Here, halloysite nanotubes/polyvinyl alcohol (HNTs/PVA) hybrid membrane with surface micro-nano structure processing using a one-step method for efficient PM2.5 capture was prepared. The filtration efficiency is 45.35% and the pressure drop is 41.57 Pa of composite membrane with a 60 wt% halloysite dosage. Specially, it resulted in a relatively safer PM index value of about 16.54, which tends to be more stringent than the restriction by Government of China (PM2.5 < 35 µg/m3). The filtration performance was mainly attributed to the controllable microroughness surface as well as the hierarchical structure constructed by one-step method, which has a functional role in obstruction and adsorption for diluted PM2.5. The methodology can employ halloysite onto various polymers, like polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN) and also polycaprolactone (PCL) to yield hybrid membranes with the similar modification of surface and structure. Such versatile membrane filters can be purposely designed and scaled up, which endows the existing hybrid membrane with great potentials in both residential and public areas pollution control to achieve a healthier living environment.

Surface Modification of Lightweight Mortars by Nanopolymers to Improve Their Water-Repellency and Durability.

The paper explores the possibility of covering the mortar with the lightweight aggregate by the nanopolymer silane and siloxane as surface hydrophobisation. The investigation involved the mortars with two types of hydrophobic agents diluted with water in a ratio of 1:4 and 1:8. Mortar wetting properties were determined by measuring the absorbability, water vapor diffusion, contact angle (CA) and surface free energy (SFE) of their structure. Surface micro-roughness and 2D topography were evaluated. Scanning electron microscopy (SEM) has shown the microstructure and distribution of pores in mortars. The reduction in absorbency after the first day of testing by 87% was shown. An improvement in frost resistance after 25 cycles by 97% and an 18-fold decrease in weight loss after the sulphate crystallization test were observed. The hydrophobic coating reduces the SFE of mortars and increases the CA. In the case of using silanes, a 9-fold increase CA was observed.

Physical Properties of Mineral and Recycled Aggregates Used to Mineral-Asphalt Mixtures.

This article presents test results and examines the possibilities of using aggregate from ceramic waste for mineral-asphalt mixtures. In addition, the mineral composition, physical and mechanical properties of aggregates from natural raw materials such as dolomite, granodiorite and waste ceramic aggregate (introduced as a partial substitute for the main aggregate) were analyzed. The shape of grains was examined by determining the shape and flatness index of aggregates, resistance to grinding and frost resistance. The tested properties have a direct impact on the durability of road surfaces. To this end, the adhesion of asphalt to the surface of the aggregates used was additionally determined. Determination of surface roughness and two-dimensional (2D) topography of tested aggregates was carried out. The aggregates microstructure examination, coupled with the energy-dispersive X-ray spectroscopy (EDS) analysis, was conducted to determine the morphology and texture of the aggregates as well as to identify the basic chemical components.

[Effect of sandblasting on the microroughness of ceramic restorations]. / Vliianie aéroabrazivnoi obrabotki na mikrosherokhovatost' konstruktsii iz stomatologicheskoi polevoshpatnoi keramiki.

The influence of aero-abrasive technology on the microroughness of the ceramic samples standardized in shape, structure, and manufacturing method was studied by comparing the results obtained from the action of alumina particles of 27 and 50 µm size under a pressure of 0.5 and 2 atm for 5 seconds at a distance of 3 cm. To objectify the features of the treated surface relief its micro-roughness has been studied. With the help of a scanning electron microscope the morphology of studied samples was visualized. The data confirming the reliable absence of differences in the microroughness between the sandblasting methods under the given conditions was obtained. Microphotographs of samples surface obtained using the mode of reflected electrons detection showed no significant structural differences between all groups of samples. Thus, sandblasting can be integrated into the general algorithm as a stage of ceramics preparation for adhesive fixation since it does not cause mechanical damage to the surface, does not fundamentally change its structure and cleans the surface from contamination.

Remineralizing Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate and Sodium Fluoride on Artificial Tooth Enamel Erosion: An In Vitro Study.

AIM: To compare in vitro the remineralizing effect of toothpastes with casein phosphopeptide-amorphous calcium phosphate (FPC-FCA) and sodium fluoride on the artificial erosion of tooth enamel. MATERIALS AND METHODS: For the first phase of artificial erosion, group I was considered as the control group without treatment or erosion. For groups II and IV, the drink was used (Coca-Cola®), for groups III and V, the drink (Inca-Kola®), and the four groups were demineralized four times a day (every 3 hours for 2 minutes) for 5 days. In the treatment phase in groups II and III, brushing was performed with sodium fluoride paste (Colgate®), groups IV and V received brushing with FPC-FCA complex (MiPaste®), and for all groups, the same procedure was performed four times a day (every 3 hours for 5 minutes) for 90 days. At the end, the microroughness of the surfaces of all the groups was evaluated by means of a Rugosimeter (Mitutoyo). RESULTS: It was evidenced that the group of sodium fluoride presented a microroughness of 2.79 µm being the group of least remineralization, but the FPC-FCA complex showed a microroughness of 1.96 µm; however, the control group presented a microroughness of 3.20 µm, and the groups sodium fluoride, FPC-FCA compared to the control group proved to be statistically significant with a p < 0.05. CONCLUSION: The remineralizing effect of FPC-FCA (MiPaste®) complex proved to be greater than sodium fluoride paste (Colgate®) under artificial enamel erosive conditions. CLINICAL IMPORTANCE: The results of this research serve as a basis for industries to generate products that have the potential for remineralization against various erosive beverages that are consumed daily. How to cite this article: Pirca K, Balbín-Sedano G, Romero-Tapia P, et al. Remineralizing Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate and Sodium Fluoride on Artificial Tooth Enamel Erosion: An In Vitro Study. J Contemp Dent Pract 2019;20(11):1254-1259.

Diatom-Inspired Silica Nanostructure Coatings with Controllable Microroughness Using an Engineered Mussel Protein Glue to Accelerate Bone Growth on Titanium-Based Implants.

Silica nanoparticles (SiNPs) have been utilized to construct bioactive nanostructures comprising surface topographic features and bioactivity that enhances the activity of bone cells onto titanium-based implants. However, there have been no previous attempts to create microrough surfaces based on SiNP nanostructures even though microroughness is established as a characteristic that provides beneficial effects in improving the biomechanical interlocking of titanium implants. Herein, a protein-based SiNP coating is proposed as an osteopromotive surface functionalization approach to create microroughness on titanium implant surfaces. A bioengineered recombinant mussel adhesive protein fused with a silica-precipitating R5 peptide (R5-MAP) enables direct control of the microroughness of the surface through the multilayer assembly of SiNP nanostructures under mild conditions. The assembled SiNP nanostructure significantly enhances the in vitro osteogenic cellular behaviors of preosteoblasts in a roughness-dependent manner and promotes the in vivo bone tissue formation on a titanium implant within a calvarial defect site. Thus, the R5-MAP-based SiNP nanostructure assembly could be practically applied to accelerate bone-tissue growth to improve the stability and prolong the lifetime of medical implantable devices.

Surface geometry of poly(ether imide) boosts mouse pluripotent stem cell spontaneous cardiomyogenesis via modulating the embryoid body formation process.

The permanent loss of cardiomyocytes may lead to the irreversible damage of myocardium in cardiovascular diseases. The induced pluripotent stem cells (iPSCs) with the capacity of differentiation into a variety of cell types including cardiomyocytes showed high potential for efficient heart regeneration. The iPSCs and iPSC-derived embryoid bodies (EBs) as well as the differentiated cardiomyocytes are highly sensitive to the biophysical cues of their microenvironment, and accordingly their behavior and function can be largely modulated by microstructure of the cell culture surface. In this study, we investigated the regulatory effect of microscale roughness on both cardiomyogenesis and secretion of EBs using poly(ether imide) (PEI) cell culture inserts with different levels of bottom roughness (R0: flat surface; R1: rough surface, Rq ∼ 4 µm; R2: rough surface, Rq ∼ 23 µm). The proliferation rate and cardiomyogenesis of EBs increased with the increase of surface roughness. The EB secretome derived from R2 surface remarkably enhanced the in vitro new vessel formation of endothelial cells, as compared to those from R0 and R1. These findings highlight the potential to improve the iPSC/EB-based restoration of cardiovascular function via microstructured biomaterials.

Analysis of Fatigue Crack Paths in Cold Drawn Pearlitic Steel.

In this paper, a fracto-metallographic analysis was performed on the cracked specimens of cold drawn pearlitic steel subjected to fatigue tests. Fatigue cracks are transcollonial and exhibit a preference for fracturing pearlitic lamellae, with non-uniform crack opening displacement values, micro-discontinuities, branchings, bifurcations and frequent local deflections that create microstructural roughness. At the micro-level, the cold drawn pearlitic steel exhibits higher micro-roughness than the hot rolled bar (this is a consequence of the manufacturing process by cold drawing), so that the actual fractured surface in the cold drawn wire is greater than that in the hot rolled bar, due to the fact that the crack deflection events are more frequent and with higher angle in the former (the heavily drawn prestressing steel wire). These findings show the relevant role on the manufacturing process by cold drawing in the fatigue crack propagation in pearlitic steel.

Role of α2ß1 integrins in mediating cell shape on microtextured titanium surfaces.

Surface microroughness plays an important role in determining osteoblast behavior on titanium. Previous studies have shown that osteoblast differentiation on microtextured titanium substrates is dependent on alpha-2 beta-1 (α2ß1) integrin signaling. This study used focused ion beam milling and scanning electron microscopy, combined with three-dimensional image reconstruction, to investigate early interactions of individual cells with their substrate and the role of integrin α2ß1 in determining cell shape. MG63 osteoblast-like cells on sand blasted/acid etched (SLA) Ti surfaces after 3 days of culturing indicated decreased cell number, increased cell differentiation, and increased expression of mRNA levels for α1, α2, αV, and ß1 integrin subunits compared to cells on smooth Ti (PT) surfaces. α2 or ß1 silenced cells exhibited increased cell number and decreased differentiation on SLA compared to wild-type cells. Wild-type cells on SLA possessed an elongated morphology with reduced cell area, increased cell thickness, and more apparent contact points. Cells on PT exhibited greater spreading and were relatively flat. Silenced cells possessed a morphology and phenotype similar to wild-type cells grown on PT. These observations indicate that surface microroughness affects cell response via α2ß1 integrin signaling, resulting in a cell shape that promotes osteoblastic differentiation.

Does surface roughness influence the primary stability of acetabular cups? A numerical and experimental biomechanical evaluation.

Most acetabular cups implanted today are press-fit impacted cementless. Anchorage begins with the primary stability given by insertion of a slightly oversized cup. This primary stability is key to obtaining bone ingrowth and secondary stability. We tested the hypothesis that primary stability of the cup is related to surface roughness of the implant, using both an experimental and a numerical models to analyze how three levels of surface roughness (micro, macro and combined) affect the primary stability of the cup. We also investigated the effect of differences in diameter between the cup and its substrate, and of insertion force, on the cups' primary stability. The results of our study show that primary stability depends on the surface roughness of the cup. The presence of macro-roughness on the peripheral ring is found to decrease primary stability; there was excessive abrasion of the substrate, damaging it and leading to poor primary stability. Numerical modeling indicates that oversizing the cup compared to its substrate has an impact on primary stability, as has insertion force.

Effects of various surface treatments for titanium on surface micro roughness, static wettability, fibronectin adsorption / 대한치과보철학회지

Purpose: This study aims to get the fundamental data which is necessary to the development direction of implant surface treatment hereafter, based on the understanding the surface structure and properties of titanium which is suitable for the absorption of initial tissue fluid by researching effects of additional surface treatments for sandblasted with large grit and acid-etched(SLA) titanium on surface micro-roughness, static wettability, fibronectin adsorption. Materials and Method: In the Control groups, the commercial pure titanium disks which is 10mm in diameter and 2mm in thickness were treated with HCI after sandblasting with 50micrometer Al2O3. The experiment groups were made an experiment each by being treated with 1) 22.5% nitric acid according to SLA+ASTM F86 protocol, 2) SLA+30% peroxide, 3) SLA+NaOH, 4) SLA+Oxalic acid, and 5) SLA+600degree C heating. In each group, the value of Ra and RMS which are the gauges of surface roughness was measured, surface wettability was measured by analyzing with Sessile drop method, and fibronectin adsorption was measured with immunological assay. The significance of each group was verified by (SPSS, ver.10.0 SPSS Inc.) Kruskal-Wallis Test.(alpha=0.05) And the correlation significance between Surface micro-roughness and surface wettability, surface roughness and fibronectin adsorption, and surface wettability and fibronectin adsorption was tested by Spearman's correlation analysis. Result: All measure groups showed the significant differences in surface micro-roughness, surface wettability, and fibronectin adsorption.(p0.05) Conclusion: Surface micro-roughness and surface wettability rarely affected the absorption of initial tissue fluid on the surface of titanium.