Effect Of Acid Etching Research Articles

Effect of acid etching on dentin wettability and roughness: Self‐etching primers versus phosphoric acid

To compare the effect of self-etching primers and phosphoric acid on the wettability and roughness of smear layer-covered and smear layer-free dentin. Three self-etching primers (Clearfil SE Bond, AdheSE, and Xeno III) and 10% (w/w) phosphoric acid (H(3)PO(4)) solution were evaluated. The substrates were midcoronal dentin with and without smear layer. For each liquid, pH, density, and surface tension were determined. Water wettability of dentin and roughness were measured before and after each etching. Wettability of self-etching primers and phosphoric acid was measured on untreated dentin. Water wettability increased after acid conditioning similarly for all the liquids used. On smear layer-covered surfaces, self-etching primers achieved a comparable wetting but with greater contact angles than phosphoric acid. However, on smear layer-free surfaces, the increasing sequence of contact angle was Clearfil SE < AdheSE < Xeno III < Phosphoric acid. The treatment with phosphoric acid (lowest pH) produced the highest roughness increase on both dentin substrates. The roughening effect of the self-etching adhesives was more evident for AdheSE and Xeno III. Self-etching primers and phosphoric acid promote similar water wettability increase. However, self-etching primers provided lower dentin roughness increase than pretreatment with phosphoric acid. The presence of smear layer did not affect the results of self-etching and phosphoric acid treatments.

Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations

The purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE – conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN – same as Group CIE, except for acid etching of the CI surface; Group RME – same as CIE, but using a resin modified GIC (RMGIC); Group RMN – same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24°C for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (α=0.05). Dye penetration scores were as follow: CIE – 2.5; CIN – 2.5; RME – 0.9; and RMN – 0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin composite- dentin interfaces than CI.

In situ atomic force microscopy and image analysis of dentine submitted to acid etching

The effect of acid etching on root dentine was analyzed with Atomic Force Microscopy using a liquid cell that allowed image acquisition while the sample was kept in contact with the etching solution. The time evolution of the etching process was evaluated both qualitatively and quantitatively. Image sequences against etching time were obtained showing a clear trend of surface cleaning and opening of dentine tubules. Image analysis methods were employed to quantify the changes on the dentine surface, through the detection and morphological measurement of dentine tubules over time. The measurements indicated an overall increase in the diameter of the tubules against time, with a saturation value between 3.5 and 5.5 microm reached after approximately 300 seconds.

Effect of Acid Etching on Surface Chemistry and Microstructure of HA and CMP Grit-Blasted Ti Surface

Grit blasting using bioactive HA and biodegradable CMP followed by acid etching has been done. HNO3 and H3PO4 were used for the etching solution by controlling the concentration and etching time to know the effect on the surface chemistry and morphology of the Ti implant. Characterization of samples was done by using SEM, EDX and surface profilometer. The contents of residues on Ti surface decreased with increasing acid concentration and etching time. It was observed that the acidic etching rate of HA grits on Ti surface was faster than that of CMP grits. And HNO3 etched more rapidly the HA and CMP grits on Ti surface, compared to H3PO4. Therefore, the surface roughness of dental implants can be controlled by having appropriate combination of acid concentration and etching time.

Swine teeth as potential substitutes for in vitro studies in tooth adhesion: A SEM observation

Animal teeth are routinely used in studies that test dental materials; however, no studies have yet proposed the use of swine teeth in laboratory tests. The purpose of this study was to compare the effects of acid etching on the dentine and enamel of human and swine teeth, aiming at the use of swine teeth as substitutes for human teeth in adhesion tests. Four human molars and four swine molars free of caries were used. For the study of enamel, two human and two swine teeth were longitudinally sectioned with a dental handpiece and a carborundum disk. For evaluation of dentine, the remaining teeth had the occlusal third of their crowns removed using a low speed diamond saw. All specimens underwent acid etching with 37% phosphoric acid for 30s. The etched surfaces were then washed with air/water spray for 10s. The specimens were then prepared for analysis in a Sterioscan 440 scanning electron microscope. It was observed a similar morphology in human and swine teeth, despite swine enamel was thinner than human enamel. Acid etching of swine enamel promoted a demineralization similar to that observed in human enamel in which the three types of Silverstone's patterns were observed. Acid etching of dentine exposed the opening of dentinal tubules in both swine and human teeth. Peritubular dentine was removed by phosphoric acid, while collagen fibrils appeared discernible in intertubular dentine. Thus, this study showed that enamel and dentine from swine and human teeth share many structural similarities after acid etching.

A triclosan-containing compomer reduces Lactobacillus spp. predominant in advanced carious lesions

To assess the antimicrobial effect of acid etching or a triclosan-containing compomer on the cultivable microflora of incompletely excavated dentinal carious lesions. Thirty detinal lesions were opened with a diamond burr. Subsequent to removal of the softened biomass a sample of dentin was taken from the cavity floor with a round bur. Ten cavities each were treated with 36% phosphoric acid (PH) for 15s, covered with a triclosan-containing compomer (TC) or received no treatment as control (CO). All lesions were restored with a compomer composite. Sampling was performed directly after etching in the PH group and at re-entry after 6 weeks in all groups. Aliquots were plated on blood agar and selective media for Lactobacilli (Rogosa) and mutans Streptococci (MSB). Cultures were incubated anaerobically for 7 days at 37 degrees C prior to quantitative assessment and biotyping of the isolates. Application of phosphoric acid resulted in initial reduction of the totally cultivable microflora (p=0.006). Evaluation of the total number of cultivable microflora after 6 weeks revealed no differences between the groups (p>0.05). Lactobacilli counts were significantly lower in the TC group compared to the PH and CO groups (p<0.05). No difference was detected between the PH and CO groups after 6 weeks. Phosphoric acid initially reduces the number of microorganisms in carious dentin but not in the longer term. The experimental triclosan composite suppresses Lactobacilli species over a period of 6 weeks.

Effect of Concentrated Sulfuric Acid-Etching on Apatite-Forming Ability of Alkaline-Treated Titanium

Concentrated H2SO4 acid was applied to pretreatment for the alkaline treatment of commercially pure titanium, and the effect of acid-etching on apatite-forming ability of alkaline-treated titanium in a simulated body fluid (SBF) was investigated. Characterization analysis revealed that the concentrated H2SO4 etching formed much amount of sodium titanate, resulting a large amount of formation of apatite in SBF. It is confirmed that the etching in concentrated H2SO4 enhance apatite-forming ability of alkaline-treated titanium.

Fluid Movement across the Resin-Dentin Interface during and after Bonding

This study evaluated the extent of water penetration through resin-dentin interfaces before and after being sealed with adhesives. Four adhesive resin systems (2 total-etch adhesives and 2 self-etching primer adhesives) were used in this study. Dentin disks were placed in a split-chamber device, and in situ fluid movement across dentin was measured, with and without physiological pressure, during bonding procedures or 24 hrs after bonding. The fluid movement across dentin occurs via dentin tubules after acid-etching. Large outward or inward fluid shifts across dentin were observed during air-drying and light-curing for resin application. The amount of fluid movement across resin-bonded dentin when total-etch adhesives were used was significantly greater than that with self-etching adhesives. The milder acid-etching effects of self-etching primers may retain hybridized smear plugs within the tubules that reduce outward fluid flow, resulting in superior dentin sealing.

Concentration dependence of superconductivity and the order-disorder transition in the hexagonal rubidium tungsten bronzeRbxWO3:Interfacial and bulk properties

We revisited the problem of the stability of the superconducting state in ${\mathrm{Rb}}_{x}{\mathrm{WO}}_{3}$ and identified the main causes of the contradictory data previously published. We have shown that the ordering of the Rb vacancies in the nonstoichiometric compounds have a major detrimental effect on the superconducting temperature ${T}_{c}.$ The order-disorder transition is of first order only near $x=0.25,$ where it cannot be quenched effectively and ${T}_{c}$ is reduced below 1 K. We found that the high ${T}_{c}'\mathrm{s}$ that were sometimes deduced from resistivity measurements and attributed to compounds with $0.25\ensuremath{\lesssim}x\ensuremath{\lesssim}0.30,$ are to be ascribed to interfacial superconductivity that generates spectacular nonlinear effects. We also clarified the effect of acid etching and set more precisely the low-rubidium-content boundary of the hexagonal phase. This work makes clear that ${T}_{c}$ would increase continuously (from $\ensuremath{\approx}2 \mathrm{K}$ up to $\ensuremath{\approx}5.5 \mathrm{K})$ as we approach this boundary $(x\ensuremath{\approx}0.20),$ if no ordering would take place---as it is approximately the case in ${\mathrm{Cs}}_{x}{\mathrm{WO}}_{3}.$ This behavior is reminiscent of the tetragonal tungsten bronze ${\mathrm{Na}}_{x}{\mathrm{WO}}_{3}$ and asks the same question: what mechanism is responsible for this large increase in ${T}_{c}$ despite the considerable associated reduction of the electron density of state ${\mathcal{D}}_{\mathrm{FE}}?$ By reviewing the other available data on these bronzes we conclude that the theoretical models that are able to answer this question are probably those where the instability of the lattice plays a major role and, particularly, the model that calls upon local structural excitations, associated with the missing alkali atoms.

Effect of acid-etching on remineralization of enamel white spot lesions

This in vitro study aimed at investigating whether full remineralization would occur in white spot lesions when the surface porosity was increased by acid-etching. The effect of fluoride was also investigated. Enamel blocks with in vitro produced white spot lesions were used. Group A was exposed to a remineralizing solution only. In group B, the lesions were etched with 35% phosphoric acid for 30 s, then treated as in group A. Group C was treated as group A + daily treatment with a fluoride toothpaste slurry (1000 ppm) for 5 min. Group D was treated as group B + the daily fluoride treatment of group C. The remineralization was measured weekly with Quantitative Light-induced Fluorescence during the experimental period. After 10 weeks of remineralization, mineral profiles were assessed with transverse microradiography. The enamel fluorescence was partly regained. There were significant differences in the lesion depth, mineral content at the surface layer, and integrated mineral loss between the groups. Addition of fluoride accelerated the remineralization only in the beginning; in later stages the process leveled out and even reached a plateau in all the groups. It was concluded that full remineralization was not achieved by etching, by the addition of fluoride, nor by the combination of both treatments in this in vitro study.

Effect of acid etching and collagen removal on dentin wettability and roughness

Effect of acid etching and collagen removal on dentin wettability and roughness

Effect of acid etching and collagen removal on dentin wettability and roughness.

It was recently reported that removal of the collagen network from etched dentin does not affect dentin bond strengths. The aim of this study was to determine if the removal of the collagen fibers results in changes in dentin roughness and wettability. Twenty cary-free extracted human third molars were sectioned parallel to the occlusal surface to expose either superficial or deep dentin. Dentin was ground flat through 600-grit SiC abrasive paper under water to provide uniform surfaces. Observed contact angle measurements were performed to assess wettability by using the axisymmetric drop shape analysis technique using water and a water-based primer. Average roughness was determined with a profilometer. The specimens were analyzed just after being ground, after etching with 35% H(3)PO(4) gel for 15 s, and after etching and deproteinization with 5% NaOCl for 2 min. Data were analyzed with two-way ANOVA and Newman-Keuls multiple comparison t test procedure. Etching resulted in an increase in surface roughness and dentin wettability. For deep dentin, collagen removal did not influence the average roughness, but it resulted in a significantly greater degree of wettability. The degree of wettability for deep dentin was greater than for superficial dentin.

Glow curves and emission spectra of burnt flints

The thermoluminescence (TL) behaviour of a group of burnt flints from a prehistoric site in North Italy has been studied. Due to incomplete burning or non-reproducible results only three samples could be reliably dated. The flints have been studied through electron microscopy with microprobe, X-ray diffraction and TL, also wavelength resolved. A new type of preparation using a hydraulic press avoids modifications of the natural TL signal. The effects of acid etching were also studied. All the samples turned out to be composed of microquartz and megaquartz. The glow-curves gave indication of incomplete burning through the appearance of a peak at about 450°C (heating rate 8°C s -1), contrary to the well-annealed samples that presented a composite peak in the 280–380°C region. Encouraging results have been obtained in the analysis of the TL emission spectra. Three emission regions have been detected: 260–330 nm, 350–500 nm and 580–640 nm. While only the middle one is usually detected by conventional 2D instrumentation, also the UV region could be probably proposed for dating burnt flint.

Effects of acid-etching on the tensile properties of demineralized dentin matrix

Objectives. Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity ( E) of human coronal dentin matrix. Methods. Small hour-glass shaped (for UTS) or I-beam shaped (for determination of E) were prepared from mid-coronal dentin of extracted human third molars. After protecting the ends with varnish, the middle of the specimens was completely demineralized in 0.5 M EDTA (pH 7). UTS was determined by tensile stressing to failure. Modulus of elasticity was calculated from stress strain curves. The results were analyzed by ANOVA and Student–Neuman–Keuls test at the 95% confidence level. Results. Brief ( ca. 1–2 min) exposure of demineralized dentin matrix to acids had no measurable effects on its tensile properties. Ten-minute exposures to 2.5% and 17.5% nitric acid lowered ( p<0.05) the UTS compared to phosphate buffered saline (PBS)-exposed controls. Exposure of the decalcified dentin to 10% citric acid containing 3% ferric chloride, 10% citric acid, 37% phosphoric acid or 17.5% nitric acid containing 3% ferric chloride for 10 min had no effect on UTS. None of these acids consistently lowered stiffness. Significance. The results indicate that relatively long exposures to acids are required to alter the tensile properties of demineralized dentin. It is unlikely that the brief exposures to acids that are used in adhesive dentistry would acutely weaken the physical properties of demineralized dentin. However, long-term studies should be done to determine if such treatment increases the susceptibility of the matrix to hydrolysis.

Effect of acid etching on the flexural strength of a feldspathic porcelain and a castable glass ceramic

This project studied the effect of altering surface topography by chemical etching on the strength of a feldspathic porcelain and castable glass ceramic. Fifty specimens of each ceramic material were subjected to five different etch times (in groups of 10). A silane coupling agent and composite resin cement were applied. Specimens were then subjected to a three-point flexural strength test. Representative specimens were examined under scanning electron microscope to elucidate more information on the effect and the depth of etch. There was no significant difference in the mean flexural strengths between the etched and nonetched groups and no significant difference between the different etching times for either material. Photomicrographs revealed dissimilar etch depths and selective dissolution of the phases. It appears that chemical etching can improve the retention of ceramic laminate veneers without significant loss of strength.

Microleakage of indirect inlays placed on different kinds of glass ionomer cement linings.

The objective of this study is to compare the marginal seal of Class II cavities restored with indirect inlays constructed on glass ionomer cement linings having different curing properties. Also the effect of acid-etching of these liners on microleakage was investigated. Mesio-occlusal and disto-occlusal cavities in 80 extracted human molars having the cervical floor below the cementoenamel junction were prepared (n:160). Half of the preparations were restored with Ceramco II porcelain and the rest with SR-Isosit resin inlay material. Liners as light curing Ionoseal light+chemically curing LCL 8 and Zionomer and chemically curing Ketac-Bond glass ionomer cements (GICs) were used. On mesial preparations GICs were acid-etched but were not on distal preparations. All inlays were cemented with Ultrabond composite material. After thermocycling the teeth were placed in a basic fuchsin dye solution for 24 h, then each tooth was sectioned. By using a stereomicroscope the extent of marginal leakage was scored and statistically evaluated. Microleakage was observed beneath all GIC linings and was more extensive between light curing GIC/dentine interface. By acid-etching of GICs the microleakage between GIC/dentine interface was increased significantly. Whether acid-etching was applied or not a significantly increased microleakage was recorded between chemically curing GIC/composite interfaces. Although the marginal microleakage was witnessed in both inlays, it appeared that porcelain inlays provided a better marginal seal, in comparison to SR-Isosit inlays.

The effect of etching on glass polyalkenoate cements

The effect of acid etching on the surface appearance and flexural strength of four glass polyalkenoate cements was investigated. Specimens were etched for intervals of 10-60 s, both at the recommended time after mixing and after a 24-h delay. The surface texture was examined microscopically. Further specimens were subjected to a 4-point bend test following etching 1 h and 24 h after mixing. Deterioration of the surface appearance occurred as the etching time was increased beyond 10 s following immediate etching. Etching after 24 h reduced surface damage, but a 10-s etch still gave the most favourable surface appearance without loss of particulate material. Etching beyond 10 s significantly reduces flexural strength.

ウシ象牙細管の細菌通過性 第１報

The penetration by bacteria through dentinal tubules was studied using a device that included portion of bovine anterior teeth. Strains of 4 genera, Streptococcus mutans, Lactobacillus casei, Staphylococcus aureus and Escherichia coli, were used for the experiment, and the effects of acid etching of dentin on the penetration of bacteria through the dentin was examined. The time required for penetration through dentinal tubules of acid-etched samples was shorter than that of unetched samples. The minimum time required for half the samples to become positive for bacterial penetration through dentin MPT50 was 4 hours for all strains chosen when the acid-etched dentin was the target. In non-acid etched samples, the MPT50 varied among the genera and ranged from 20 hours to 48 hours; the speed of penetration was Sta. aureus = L. casei greater than Str. mutans greater than E. coli. Observation under the scanning electron microscope indicated that the smeared layer was completely coated on the surface of the prepared cavity, and when bacterial penetration occurred, a portion of the smear layer on the dentin disappeared. In longitudinal sections, the penetration by the bacteria into the tubules was visible. From these results, it is suggested that the smeared layer have an important effects on bacterial penetration through these tubules.

Effect of Acid Etching on the Primary Enamel Smooth Surfaces

Effect of Acid Etching on the Primary Enamel Smooth Surfaces

Effect of Acid Etching on the Ground Primary Enamel

Effect of Acid Etching on the Ground Primary Enamel