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PubMed2000

Effect of etching and sandblasting on bond strength to sintered porcelain of unfilled resin.

This study determined the bond strength of an unfilled resin joined to a feldspathic porcelain for the purpose of evaluating the retentive performance of the prepared material surfaces. Porcelain disks (VMK 68 dentin) were either air abraded with alumina (AAA) or etched with one of the following five etchants: (1) ammonium hydrogen bifluoride (AHB); (2) acidulated phosphate fluoride (APF); (3) hydrofluoric acid (HFA); (4) phosphoric acid (PHA); and (5) sulfuric acid-hydrofluoric acid (SHF). Specimens ground with abrasive paper were also used as controls. After surface preparation, the two different sized porcelain disks were bonded together with a methyl methacrylate-based resin initiated with tri-n-butylborane (MMA-TBB resin). Shear bond strengths were determined both before and after thermocycling. Before the thermocycling, the greatest bond strengths (21.3 and 23.7 MPa) were generated with the use of the SHF and HFA agents, followed by the AHB agent (18.4 MPa). Reduction in bond strength after thermocycling was significant for all groups, although the SHF- and HFA-treated groups exhibited bond strengths greater than 15 MPa even after the thermocycling. The results indicated the effectiveness of the SHF- or HFA-etching for retaining the acrylic resin to the porcelain. However, ageing testing also revealed insufficient retentive characteristics of the acrylic resin by etching alone.

Acid Etching, Dental↗

PubMed1985

Pyruvic acid as an etching agent in clinical dentistry.

The objective of this study was to evaluate the use of pyruvic acid as an alternative etching agent to phosphoric acid (H3PO4). Solutions containing 5, 10, 15, 20, 25, and 30 m/m % pyruvic acid and 50% m/m H3PO4 were prepared. The tensile bond strengths of a composite resin to enamel surfaces etched with the respective etching agents were determined. The rates of etching of enamel surfaces by each of the etching solutions were evaluated. Unground and polished enamel surfaces were etched with the respective etching solutions and the surfaces examined by scanning electron microscopy. The tensile bond strengths of the resin to enamel surfaces etched with 10-30% pyruvic acid exceeded those obtained on enamel surfaces etched with 50% H3PO4. The rates of etching of all the pyruvic acid solutions were significantly less than of H3PO4. Well-defined etching patterns were observed on the enamel surfaces etched with all the etching solutions. The results of this laboratory study suggest that pyruvic acid may be a suitable alternative to phosphoric acid as an etching agent in clinical dentistry.

Acid Etching, Dental↗

PubMed2006

Scanning electron microscopy evaluation of the effect of etching agents on human enamel surface.

Acid etching promotes microporosities on enamel surface, which provide a better bonding surface to adhesive materials. The purpose of this study was to comparatively analyze the microstructure of enamel surface after etching with 37% phosphoric acid or with two self-etching primers, Non-rinse conditioner (NRC) and Clearfil SE Bond (CSEB) using scanning electron microscopy. Thirty sound premolars were divided into 3 groups with ten teeth each: Group 1: the buccal surface was etched with 37% phosphoric acid for 15 seconds; Group 2: the buccal surface was etched with NRC for 20 seconds; Group 3: the buccal surface was etched with CSEB for 20 seconds. Teeth from Group 1 were rinsed with water; teeth from all groups were air-dried for 15 seconds. After that, all specimens were processed for scanning electron microscopy and analyzed in a Jeol 6100 SEM. The results showed deeper etching when the enamel surface was etched with 37% phosphoric acid, followed by NRC and CSEB. It is concluded that 37% phosphoric acid is still the best agent for a most effective enamel etching.

Acid Etching, Dental↗

PubMed2005

A severe peak tailing of phosphate compounds caused by interaction with stainless steel used for liquid chromatography and electrospray mass spectrometry.

A severe peak tailing was observed for adenosine 5'-monophosphate in flow injection analysis with stainless steel tubing and water/methanol mixture (1:1, v/v) as carrier. The cause of the peak tailing was investigated by focusing on the chemical structure of the analytes, the material used for the analytical systems and the composition of the carrier. We clarified that the peak tailing was caused by the interaction between phosphate residues in the analytes and stainless steel. The severe peak tailing did not occur with stainless steel tubing when the phosphate compounds were analyzed with carrier containing phosphoric acid or phosphate buffer. The findings indicate that such ill peak profiles are usually not considerable in conventional HPLC separation because phosphoric acid or phosphate buffer is quite commonly used in eluents. In LC-MS, however, the use of phosphoric acid and phosphate buffer is usually avoided because of their non-volatility; therefore this interaction between stainless steel and phosphate compound becomes predominant and results in severe peak tailings. We also found an effective method for avoiding the interaction. When stainless parts, such as LC tubing and ESI spray capillary, were treated with phosphoric acid prior to analysis, the peak profiles of the phosphate compounds were dramatically improved, even when non-phosphate buffer is used as carrier.

Chromatography, Liquid↗

PubMed1997

Effects of acid etching on dentin surface: SEM morphological study.

The aim of this in vitro study was to evaluate, using scanning electron microscopy (SEM), the effects of acid solutions on dentin surface, and to analyze the depth of demineralization that the acid solutions cause on dentin, using different acids. Fifteen 3-mm thick dentin discs were prepared from the middle third of human molars. Standard smear layer was prepared on the dentin surface using 600 grit sandpaper, for 1 minute. The acids used were 10%, 35% and 37.5% phosphoric acid and 10% maleic acid, for 15 seconds, washed and dried. The control group received no treatment. Dentin discs were fractured, observed on the horizontal surface and also on the fractured surface to evaluate the depth of demineralization. Specimens were immersed in 4% glutaraldehyde in phosphonate buffer, and prepared for SEM examination at 2000X and 4000X magnification. Acid etching of dentin, regardless of the concentration of phosphoric acid, caused removal of the smear layer, exposing the apertures of dentinal tubules. This was not observed when 10% maleic acid was used. At the fractured surface, one could observe an increase in demineralization of the width of dentinal tubules, to a specific depth of about 8.19 to 11 mm, except for 10% maleic acid.

Acid Etching, Dental↗

PubMed2005

Effect of self-etching adhesives on dentin permeability in a fluid flow model.

STATEMENT OF PROBLEM: Numerous self-etching bonding systems exist, with composition differing from one product to another. It is important for the clinician to know if they are all equally effective, and whether they provide an effective seal between dentin and restorative materials. PURPOSE: This study was designed to measure the hydraulic conductance of physiologic saline across dentin after application of various self-etching bonding systems or of a 1-bottle adhesive system preceded by a phosphoric acid etch. MATERIAL AND METHODS: One hundred extracted noncarious human third molars from patients 18-25 years old were used for this study. Dentin disks were cut from crown segments parallel to the occlusal surface at the top of the pulp cavity. The 100 disks, each 1 mm thick, were divided into 10 groups (n=10 per group), each of which was treated with 1 of 9 self-etching systems-AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, Etch & Prime 3.0, Prime & Bond NRC Nt, One-Up Bond F, optiBond solo Plus Self Etch, Prompt L-Pop, or Xeno III-or a control bonding system (Prime & Bond NT) preceded by a phosphoric acid etch. Hydraulic conductance, the volume of fluid transported across a known area of surface (0.28 cm2) per unit time under a unit pressure gradient (200 cm H2O), was analyzed for the adhesive systems using a fluid flow apparatus (Flodec). First, both sides of each specimen were etched with 36% phosphoric acid for 30 seconds, and the hydraulic conductance was measured every 30 seconds for 15 minutes. The initial set of measurements served as the reference value for each specimen. The measurements were repeated when a smear layer had been formed and, finally, after 1 of the 10 bonding systems had been applied. The data were analyzed using a 1-way ANOVA and Duncan's multiple range test (alpha=.05). RESULTS: The control 1-bottle adhesive used with a phosphoric acid pre-etch did not provide the largest reduction in penetration (42.3%). The greatest mean reduction (68.9%, P<.05) was observed with the self-etching product Xeno III. The mean reduction for the other materials tested were: One-Up Bond F, 60.5%; AdheSE, 58.2%; Etch & Prime 3.0, 56.8%; Adper Prompt L-Pop, 51%; optiBond solo Plus Self Etch, 45%; Clearfil SE Bond, 35.5%, Prime & Bond NRC Nt, 16.4%; and Prompt L-Pop, 16.3%. CONCLUSION: Within the limitations of this study, the self-etching systems tested produced different reductions in dentin permeability. For some, the reduction was much greater than the decrease in dentin permeability provided by the bonding system with a phosphoric acid pre-etch; for others, the reduction was small.

Adolescent↗

PubMed1994

Adhesion of a total-etch phosphate ester bonding agent.

This study evaluated the shear bond strengths of a phosphate ester bonding agent, Clearfil Photo Bond, using different phosphoric acid gels to etch dentin. The study also tested the shear bond strength of the Clearfil Liner Bond system. Sixty extracted human molars were ground to expose mid-coronal dentin and were randomly assigned to six treatment groups. The first group was left unetched as a control. In the next four groups, dentin was etched with phosphoric acid gels: K-etchant (40% with silica thickener); Uni-Etch (polymer-thickened 32%); All-Etch (10%, polymer thickener); or Ultra-Etch (10%, silica thickener). Specimens in the sixth group were etched with 10/20 Ca, a gel with 10% citric acid and 20% calcium chloride. All specimens were bonded with Clearfil Photo Bond and XRV Herculite resin composite. Specimens in the final group also received SA Primer and Protect Liner. After thermocycling, shear bond strengths were determined using an Instron universal testing machine. Mean shear bond strengths ranged from 1.3 MPa (control) to 15.9 MPa (Clearfil Liner Bond). The shear bond strengths of specimens that had been etched with phosphoric acid gels were in the range of 5-8 MPa, and were not significantly affected by either acid concentration or thickener type. SEM examination showed that phosphoric acid demineralized dentin to a depth of 5 microns, while 10/20 Ca demineralized dentin to a depth of only 1-1.5 microns.

Acid Etching, Dental↗

PubMed1976

Cortisol effect on collagen biosynthesis in embryonic explants and in vitro hydroxylation of protocollagen.

The effect of increasing doses of hydrocortisone acetate, hydrocortisone phosphoric acid complex, and hydrocortisone sodium succinate on collagen biosynthesis was assayed in two different systems. I. Explants of chicken embryo tibiae showed decreased biosynthesis of [14C]hydroxyproline and total and glycosylated [14C]hydroxylysine under the influence of high doses of hydrocortisone. With the lower doses of hydrocortisone acetate, no effect was noticed. The total uptake of the precursor amino acids followed patterns similar to those of collagen biosynthesis. II. Hydroxylation of [14C]proline labelled protocollagen by protocollagen proline hydroxylase was inhibited by high doses of hydrocortisone acetate, hydrocortisone phosphoric acid complex, and hydrocortisone sodium succinate. III. A decreased diffusion of collagen to the medium with increasing doses of hydrocortisone acetate, hydrocortisone phosphoric acid, and hydrocortisone sodium succinate was noticed. IV. No further hydroxylation of new-synthesized collagen was obtained under the influence of hydrocortisone phosphoric acid and hydrocortisone sodium succinate, when the undialyzable material was used as a substrate for protocollagen proline hydroxylase.

Animals↗

PubMed1993

Clinical effects of reduction of acid concentration on direct bonding of brackets.

A total of 600 metal mesh-backed brackets were directly bonded to the anterior teeth of randomly selected orthodontic patients. Prior to bonding, enamel etching was carried out with 37% phosphoric acid on one side and with 2% phosphoric acid on the other side. The etch duration was 30 seconds. After 1 year no statistically significant difference was found between the failure rates of the two etching procedures. The assessment of the Adhesive Remnant Index (ARI) after debonding, however, revealed that the application of 37% acid resulted in significantly higher amounts of residual adhesive left on the teeth. The present study demonstrates that a phosphoric acid concentration of 2% can be sufficient for bracket bonding on anterior teeth.

Adhesives↗

PubMed2001

Effect of enamel pretreatments on bond strength of compomer.

OBJECTIVES: The objective of this study was to evaluate the effect of various enamel surface treatments on the bond strength of a compomer to enamel. METHODS: Ground bovine enamel specimens were divided into four groups. A compomer (F2000, 3M) was bonded to the specimens using different enamel surface treatments. Two groups examined the effect of application of the F2000 self-etching primer/adhesive (3M) with respect to static or dynamic priming. A third examined use of the primer/adhesive after phosphoric acid etching, and the fourth (control) group provided bond strength of the compomer to phosphoric acid etched enamel with a resin bonding system (Single Bond, 3M). Shear bond strengths for the specimens were measured after 24h storage in water at 37 degrees C. Effects of the various surface treatments on enamel were examined by SEM. RESULTS: Significant differences in bond strength of compomer to enamel were found that were related to the various surface pretreatments. Dynamic priming resulted in higher enamel bond strengths than static priming, and the best bond strengths were obtained when the enamel was etched with phosphoric acid. SEM analysis showed that depth of etch and resin penetration was also directly related to the bond strengths measured. SIGNIFICANCE: Bond strength of compomer to enamel is significantly affected by the method of pretreatment of the enamel.

Acid Etching, Dental↗

PubMed2000

Effects of acids and additives on the susceptibility of human dentine to denaturation.

The purpose of this study was to evaluate the efficacy of a number of additives to acid conditioners at reducing the denaturation of dentine collagen. Dentine collagen is normally not very susceptible to trypsin attack. After denaturation, however, it becomes more susceptible to the action of trypsin. Slabs of human dentine were dipped in water or acidic conditioners (10% citric acid or 37% phosphoric acid) containing no additives, 5 or 10% NaCl, 3 or 6% ferric chloride or 50% hydroxyethylmethacrylate (HEMA) for 15 or 60 s, followed by rinsing. The slabs were then exposed to trypsin for 24 h to solubilize any denatured collagen. The solubilized collagen was hydrolysed to liberate hydroxyproline that was quantitated spectrophotometrically. The amount of hydroxyproline (HOP) liberated was indicative of the amount of dentine collagen that was denatured by the test solutions. The only additive that consistently reduced HOP release was 50% HEMA, and this only occurred in the 60 s exposure group. Thus, the use of salt additives to acidic conditioners has little protective effect.

Acid Etching, Dental↗

PubMed1993

Bond strength of resin-reinforced glass ionomer cements after enamel etching.

This study evaluated the shear bond strength of resin-reinforced glass ionomers to enamel etched or unetched. Human, non-carious extracted permanent molars stored in distilled water were used. Flat buccal and lingual enamel surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into six groups of 5 teeth (10 surfaces) each: Group 1: Fuji II LC, no enamel etching; Group 2: Fuji II LC, enamel etched with 10% phosphoric acid for 10 seconds; Group 3: Dyract, no enamel etching; Group 4: Dyract, enamel etched with 10% phosphoric acid for 10 seconds; Group 5: Photac-Fil, no enamel etching; Group 6: Photac-Fil, enamel etched with 10% phosphoric acid for 10 seconds. Cylindrical samples of the glass ionomers were prepared in plastic molds and bonded to the enamel surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, and sheared with an Instron at a crosshead speed of 0.5 mm/minute. The results (in MPa) were: Group 1: 11.29 +/- 4.84; Group 2: 19.64 +/- 5.43; Group 3: 8.26 +/- 3.61; Group 4: 22.04 +/- 5.40; Group 5: 2.05 +/- 3.05; Group 6: 9.12 +/- 6.61. ANOVA and Student-Newman-Keuls procedure revealed that on etched enamel, Fuji II LC and Dyract had a significantly higher bond strength than all the other groups tested (P < 0.0001), but not significantly different between each other. With these two groups, cohesive failure within the material was recorded in all samples while in the unetched samples, all specimens displayed an adhesive failure (glass ionomer-enamel interface). All samples with Photac-Fil, with or without enamel etching had adhesive failures.

Acid Etching, Dental↗

PubMed1978

[Reaction mechanism of succinyl CoA synthetase from pigeon thoracic muscle].

The ability of succinyl-CoA-synthetase from pigeon thoracic muscle to interact with ATP is investigated. gamma-32P-ATP and 8-14C-ATP were used in experiments. It is found that the enzyme, when reacting with ATP in the presence of Mg2+, forms a complex containing 2 moles of ATP residue and 2 moles of phosphoric acid residue (splitted from ATP) per 1 mole of protein. After 2 hours of incubation at 0-4 degrees C, the complex is converted into another one, containing 4 residues of phosphoric acid per 1 mole of @protein. Both complexes are active, and their incubation with succinate and CoA results in the formation of succinyl-CoA. The reaction capacity of these enzyme complexes with some reaction substrates is investigated. The enzyme complex containing 2 phosphoric acid residues and 2 nucleotide residues is found to interact neither with CoA, nor with succinate. The enzyme complex containing 4 phosphoric acid residues does not react with CoA, but it interacts with 14C-succinate, releasing inorganic phosphate in the amount equivalent to the equimolar amount of protein-binding succinic acid.

Adenosine Triphosphate↗

PubMed1991

[Ergotropic effects through the nutritive use of organic acids].

Experimental data showed a significant improvement of growth rate and efficiency of feed utilization of young animals (piglets) by the dietary inclusion of organic acids. These ergotropic effects were mainly observed with citric acid, fumaric acid and formic acid as well as with Ca and Na formate. The merely dietary pH lowering with an inorganic acid (ortho-phosphoric acid) failed to show a nutritive efficacy. Studies on the mode of action of organic acids indicated a higher protein and energy digestibility, a lower stomach pH and reduced levels of NH3 and lactic acid in the stomach and duodenal digesta. Furthermore, the duodenum mainly contained a significant lower bacterial population for E. coli and enterococci. By this way the burden of metabolism of the host may be reduced which results in a higher overall performance.

Animal Feed↗

PubMed1981

Loss of surface enamel after acid etching procedures and its relation to fluoride content.

The etching of an enamel surface with a strong acid causes loss of surface contour together with a roughening of the enamel, which is necessary for proper adhesion of the bonding agent. It is known that the fluoride concentration plays an important role in the reduction of enamel solubility. The objective of this investigation was to measure the bulk enamel loss because of acid etching with phosphoric acid, with special emphasis on the fluoride content of tooth enamel. It was shown that fluoridated enamel has a high acid-resistant layer 2 to 4 microns in thickness. In some teeth the enamel is locally so resistant that, even after a 3-minute etching period, practically no material is removed. Since considerable amounts of topically applied fluoride ions are known to leak out, it is advisable to omit fluoride application shortly prior to the bonding procedure.

Acid Etching, Dental↗

PubMed1989

The effect of various surface treatments on the shear strength between composite resin and glass-ionomer cement.

The effect of various surface treatments on the shear bond strength of composite resin to a glass-ionomer cement has been studied. Acid etching with phosphoric acid and polyacrylic acid, roughening by way of grinding or air drying, the use of a dentine bonding system and a silane coupling agent were the variables. Acid etching, grinding or air drying the surface of the cement had a significant effect on the bond strength. The use of a dentine bonding system led to a significant improvement in the resulting bonding. Silane coupling agent did not improve the bonding. Composite resin did not adhere to a smooth cement surface, but the application of the dentine bonding system on such a surface produced a moderate bond.

Acid Etching, Dental↗

PubMed2004

An evaluation and comparison of orthodontic bracket bond strengths achieved with self-etching primer.

The bonding of orthodontic brackets to enamel is a multistep process. To simplify bonding and decrease chair time, Transbond Plus Self-Etching Primer (3M Unitek, Monrovia, Calif) has been introduced; the primer combines the etching, rinsing, and priming steps. This in vitro study evaluated the shear bond strengths and interoperator variability of self-etching primer, as compared with conventional phosphoric acid etching with 2 common orthodontic resins. A total of 214 teeth were bonded, according to the following protocols: group A: self-etching primer plus Transbond XT light-cured resin (3M Unitek); group B: 35% phosphoric acid (15 seconds) plus Transbond XT resin; and group C: 37% phosphoric acid (15 seconds) plus Enlight bonding resin (Ormco, Glendora, Calif). Significantly higher bond strengths were seen in group B than in group A (P =.004) and group C (P =.002). The mean shear bond strengths of group A were not significantly different from those of group C (P =.99). When 3 orthodontists bonded a total of 60 premolars using the protocols of groups A and B, significant differences in shear bond strengths and strength ranking were found. The mean values they obtained using the self-etching primer were not significantly different, but significant differences in mean values were found between operators when the phosphoric acid-etching technique was used.

Acid Etching, Dental↗

PubMedDate not supplied

Direct pulp capping with a dentin bonding system in human teeth: a clinical and histological evaluation.

This study evaluated the pulpal response in human dental pulp to direct pulp capping with the Single Bond Adhesive System (SBAS) after 10% or 37% phosphoric acid etching and after capping with Calcium Hydroxide (CH). The degree of bleeding and hemostasis conditions was considered during the adhesive technique. The pulps of 78 sound premolars were capped with SBAS after 37% phosphoric acid etching (Group I) or 10% phosphoric acid etching (Group II) and CH (Group III-control). The cavities were restored with a resin composite (Charisma). After 1, 3, 7 and 30 days, the teeth were extracted and processed for light microscopical examination (H/E, AgNOR silver stain and Brown-Brenn). The patients were followed for postoperative symptomatology evaluation. Clinical results showed the possibility of hemostasis with saline solution only. There was no statistical difference between bleeding generated by 10% and 37% acid solutions. In some cases, contact of the pulp tissue with SASB started the bleeding process, thus damaging the adhesive technique. The histological response was similar in Groups I and II, without signs of cellular differentiation and dentin neoformation up to 30 days. Bacteria were not observed in any specimens. In the control group (CH) at day 7, the pulps exhibited cells with high synthetic activity (Ag-NOR-positive) underneath the area of coagulation necrosis. Dentin bridging was observed at the thirtieth day. The postoperative period was asymptomatic for all groups. In conclusion, SBAS should be avoided for vital pulp therapy, while CH remains the capping agent of choice for mechanically exposed human dental pulp.

Acid Etching, Dental↗