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PubMed2006

Effect of conditioners on bond durability of resin composite to Nd:YAP laser-irradiated dentin.

The aim of this study was to evaluate the effect of conditioners (sodium hypochlorite (NaOCl), Roth's ethylenediaminetetraacetic acid (EDTA), and phosphoric acid) on shear bond strength and morphology of Nd:YAP laser-irradiated dentin. In particular, the key focus was on the bond durability between resin composite and treated dentin after being subjected to thermocycling in artificial saliva between 5 degrees C and 55 degrees C. Results indicated that the application of phosphoric acid to laser-irradiated dentin produced a bond strength comparable to those using NaOCl and EDTA. Further, dentinal tubules which were closed after laser irradiation opened following the treatment with conditioners. When subjected to 3,000 thermocycles, the mean shear strength of the samples treated by the three conditioners following laser irradiation ranged from 9.7 to 12.6 MPa with a reduction of 25-33%--a reduction rate lower than that obtained using acid etching alone (50%). Among the three conditioners tested, only phosphoric acid treatment demonstrated an enhanced effect on bond durability of laser-irradiated dentin.

Acrylic Resins↗
PubMed2000

Pilot study of conditioner/primer effects on resin-dentin bonding after provisional cement contamination using SEM, energy dispersive x-ray spectroscopy, and bond strength evaluation measures.

STATEMENT OF PROBLEM: Previous studies have shown that provisional cement cannot be completely removed from the dentin surface and the remnants inhibit adhesion of resin cement to dentin. PURPOSE: This study investigated the effects of dentin conditioners on resin-dentin bonding after provisional cement contamination. MATERIAL AND METHODS: A total of 216 bovine dentin specimens were divided into 2 groups with and without provisional cement coating on the dentin surface. Each group was further divided into 3 subgroups with 2 conditioning methods and without dentin conditioning (36 specimens per subgroup). The 2 methods applied were (1) phosphoric acid etching and (2) phosphoric acid etching, followed by sodium hypochlorite gel. Provisional cement was completely removed with a curette before dentin conditioning. Stainless steel rods were luted to dentin surfaces with Panavia 21 resin cement. Tensile bond strengths were measured before and after thermocycling. The dentin surface was analyzed by SEM and energy dispersive x-ray spectroscopy. Three-way ANOVA and Scheffe's comparison test were performed (P =. 05). RESULTS: Bond strength was significantly influenced by provisional cement application, type of dentin conditioning, and thermocycling. Bond strength decreased when treated with provisional cement, but the decreased strengths were restored to their original values or higher by both dentin conditioners used. Specimens treated with sodium hypochlorite gel applied after phosphoric acid etching demonstrated the highest bond strengths with good stability after thermocycling. CONCLUSION: Application of sodium hypochlorite gel after phosphoric acid etching was more effective than etching with phosphoric acid alone to eliminate the inhibitory effect of provisional cement remnants on adhesion between resin cement and dentin.

Acid Etching, Dental↗
PubMed1992

Adhesion of dentin bonding agents after smear layer treatments.

The effect on bond strength of smear layer removal (40% polyacrylic acid or 10% phosphoric acid) versus smear layer conditioning for dentin bonding agents requiring conditioning was compared. Results indicated no difference in shear bond strength for groups in which the smear layer was conditioned or removed with phosphoric acid. Smear layer removal with polyacrylic acid resulted in lower bond strengths between DBAs and dentin than either phosphoric acid removal or conditioning (P less than 0.01). Scanning electron photomicrographs of dentin treated with each dentin bonding agent revealed various surface morphologies.

Acid Etching, Dental↗
PubMed2000

The effect of enamel air abrasion on the retention of bonded metallic orthodontic brackets.

The purpose of this study was to compare the conventional acid-etch technique with an air abrasion surface preparation technique. Eighty freshly extracted noncarious human premolar teeth were randomly divided into the following 4 groups: (1) acid etched with 37% phosphoric acid for 15 seconds (Express Dental Products, Toronto, Canada), (2) sandblasted with 50 mu aluminum oxide by a microetcher (Danville Engineering Inc, Danville, Calif), (3) polished with pumice followed by acid etched with 37% phosphoric acid for 15 seconds, (4) sandblasted with 50 mu aluminum oxide by a microetcher followed by acid etched with 37% phosphoric acid for 15 seconds. All the groups had stainless steel brackets (Dentaurum, Standard Edgewise) bonded to the buccal surface of each tooth with no-mix adhesive (Express Dental Products, Toronto, Canada). A Lloyd testing machine (Lloyd Instrument LR 30K; Segensworth West, Foreham, UK) was used to determine tensile bond strengths at a crosshead speed of 0.5 mm/sec. The mean bond strength values of these are as follows: the only sandblasted group was 38.05 +/- 9.93 N; the only acid-etched group was 62.72 +/- 11.44 N; the group that was polished with pumice followed by acid etched was 69.78 +/- 14.87 N; and the group that was sandblasted followed by acid etched was 89.31 +/- 13. 34 N. The statistical analysis was done by an analysis of variance and Scheff¿e test. The sandblasting followed by acid etching group had significantly higher bond strength values when compared to the other 3 groups. This study showed that sandblasting should be followed by acid etching to produce enamel surfaces with comparable bond strength. The current findings indicate that enamel surface preparation using sandblasting with a microetcher alone results in a significantly lower bond strength and should not be advocated for clinical use as an enamel conditioner.

Acid Etching, Dental↗
PubMed2003

Effects of tooth-conditioning agents on bond strength of a resin-modified glass-ionomer sealant to enamel.

OBJECTIVES: The purpose of this study was to evaluate the effects of tooth-conditioning agents on bond strength of resin-modified glass-ionomer sealant (Fuji III LC) to bovine enamel as well as on dissolution of calcium ions from the bovine enamel surfaces. METHODS: The enamel surfaces of bovine lower incisors were treated with 10 and 20% polyacrylic acid, 12% citric acid and 35% phosphoric acid for 20s. Fuji III LC was applied to the etched enamel surfaces, and the shear bond strength of each specimen was measured using an Instron Universal Testing Instrument. The amounts of calcium ions dissolved from the treated enamel surfaces were also measured using a polarized Zeeman atomic absorptiometer. RESULTS: In specimens pretreated with distilled water, 10% polyacrylic acid, 20% polyacrylic acid, 12% citric acid and 35% phosphoric acid, the mean values of shear bond strength were 5.5, 12.5, 15.2, 15.2 and 15.1MPa, respectively, and the amounts of Ca(2+) dissolved from the enamel surfaces were 5.6, 41.4, 88.5, 131.6 and 588.3 microg/cm(2), respectively. CONCLUSIONS: The adhesion of a resin-modified glass-ionomer sealant to bovine enamel was significantly improved by the use of tooth-conditioning agents. Especially, treatment of an enamel surface with 20% polyacrylic acid results in good shear both strength and relatively small degree of enamel erosion.

Acid Etching, Dental↗
PubMed2006

Effect of different bonding conditions on the shear bond strength of two compomers to bovine dentin.

AIM: Despite the improvements to compomer materials, the bond strength of these materials remains inferior to "composite/resin bonding" systems and limits their clinical use. The purpose of this study was to evaluate the effect of acidic conditioning with phosphoric acid and Prompt L-Pop (PLP) on the shear bond strength of two compomers Dyract AP (DAP) and Composan Glass (CG) to dentin. METHODS AND MATERIALS: Sixty extracted bovine teeth were used to test the shear bond strength of two compomers to flat dentin labial surfaces. The dentin specimens were randomly assigned to six groups of ten specimens each: Group 1: DAP and Prime & Bond NT (PBNT); Group 2: DAP/PBNT with a 15 second dentin etch prior to bonding; Group 3: DAP placed with PLP adhesive; Group 4: CG and Compobond NE (CBNE); Group 5: CG/CBNE with a 15 second dentin etch; and Group 6: CG placed with PLP adhesive. The specimens were stored at 37 masculineC with 100% humidity for 24 hours then mounted and sheared using an Instron Universal Testing Machine at a cross head speed of 0.5 mm/min. The results were recorded in Mega Pascals (MPa). The sheared specimens were examined under a light microscope, and the type of failure (adhesive, cohesive, or mixed) was recorded. RESULTS: The mean dentin shear bond strength value (MPa) for the groups was: Group 1 (11.6+/-3.9); Group 2 (13.2+/-3.3); Group 3 (12.4+/-2.0); Group 4 (13.0+/-4.3); Group 5 (19.3+/-3.7); and Group 6 (13.1+/-3.0). One way analysis of variance (ANOVA) and Tukey HSD post-hoc tests detected a significantly higher bond strength (P = 0.003) for group 5. For groups 1, 3, 4, and 6, the mode of failure was mostly adhesive. When acid etching of dentin was performed (groups 2 and 5), cohesive fracture within dentin was the predominant mode of failure. Acid etching and the use of PLP significantly reduced the number of adhesive fractures and reduced variability in the shear bond strength results. CONCLUSIONS: Acid etching significantly increased the shear bond strength of CG to dentin but did not affect DAP. The application of PLP resulted in a shear bond strength not statistically different from PBNT or CPNE. CG bond to dentin is improved with acid etching using phosphoric acid. However, PLP provided no significant improvement in the shear bond strength of DAP and CG.

Acid Etching, Dental↗
PubMed2002

Simultaneous analysis of oxidized and reduced glutathione in cell extracts by capillary zone electrophoresis.

Glutathione (GSH) and glutathione disulfide (GSSG) levels in cells constitute a thiol redox system. They can be used as an indicator of oxidative stress of the cell. In this study, a capillary zone electrophoresis (CZE) method is described that enables quantitation of GSH and GSSG from cellular extracts. The CZE buffer used was 20 mM ammonium acetate containing 5% (v/v) acetic acid at pH 3.1 in conjunction with a polybrene coated capillary operated in reverse polarity mode. Effects of different acids used to prepare cell samples were investigated on CZE performance. The acids include meta phosphoric acid (MPA), trichloroacetic acid (TCA), phosphoric acid (PA) and sulfosalicylic acid (SSA) and are used to stabilize GSH and GSSG before performing CZE analysis. The method features a limit of detection of 4 microM and a limit of quantitation of 12 microM for both GSSG and GSH and recoveries of 94% for GSH and 100% for GSSG. Quantitative analysis of GSSG and GSH in HaCaT cell extracts (5% SSA, w/v) was performed with this method and changes in the ratio of GSH to GSSG in N-ethylmaleimide treated cell sample was observed by comparing with control cell samples.

Cell Extracts↗
PubMedDate not supplied

Micromorphological study of resin-dentin interface of non-carious cervical lesions.

This study examined the interfaces between two dentin adhesives, namely, One Coat Bond, Clearfil SE Bond and a resin-modified glass ionomer cement (Fuji II LC) and the dentin of non-carious cervical lesions (NCCLs) with FE-SEM, and compared them with the interfaces produced with "normal" dentin. Fifteen human premolars each with a buccal NCCL were used. Cervical cavities were prepared on the lingual surface of the same teeth for the normal (control) dentin. All lesions and prepared cavities were cleaned with a slurry of pumice and water. The teeth were randomly divided among the three products that were applied according to the manufacturers' instructions. For the resin-bonded specimens, the cavities were restored with resin composite. All specimens were stored in 37 degrees C tap water. Resin-bonded specimens were observed using FE-SEM after treatment with 10% phosphoric acid, and 10% phosphoric acid and 5% sodium hypochlorite (NaOCl). The resin-modified glass ionomer cement (RM-GIC) specimens were observed after 10% phosphoric acid and 5% NaOCl treatment. The hybrid layer could be observed for the two adhesive systems in all specimens, but the thickness varied depending on the bonding system used and the dentin substrate. The results suggested that the hybrid layer produced in normal dentin was slightly thicker than that of NCCLs. Further, the hybrid layer thickness decreased in all specimens after NaOCl treatment.

Bicuspid↗
PubMed2006

Distribution of natural radionuclides in the production and use of phosphate fertilizers in Brazil.

The Brazilian phosphate fertilizer is obtained by wet reaction of igneous phosphate rock with concentrated sulphuric acid, giving as final product, phosphoric acid and dehydrated calcium sulphate (phosphogypsum) as by-products. Phosphoric acid is the starting material for triple superphosphate (TSP), single superphosphate (SSP), monoammonium phosphate (MAP) and diammonium phosphate (DAP). The phosphate rock used as raw material presents in its composition radionuclides of the U and Th natural series. Taking this into account, the main aim of this paper is to evaluate the fluxes of natural radionuclides and radioactive disequilibria involved in the Brazilian industrial process of phosphoric acid production; to determine the content of radioactivity in several commercial fertilizers produced by this industry; to estimate their radiological impact in crop soils and the long term exposure due to their application. Radiological characterization of phosphate rock, phosphogypsum and phosphate fertilizers was performed by alpha and gamma spectrometry. The fertilizer samples, which are derived directly from phosphoric acid, MAP and DAP, presented in their composition low activity concentrations for 226Ra, 228Ra and 210Pb. As for U and Th, the concentrations found in MAP and DAP are more significant, up to 822 and 850Bqkg(-1), respectively. SSP and TSP, which are obtained by mixing phosphoric acid with different amounts of phosphate rock, presented higher concentrations of radionuclides, up to 1158Bqkg(-1) for (238)U, 1167Bqkg(-1) for (234)U, 1169Bqkg(-1) for 230Th, 879Bqkg(-1) for 226Ra, 1255Bqkg(-1) for 210Pb, 521Bqkg(-1) for 232Th, 246Bqkg(-1) for 228Ra and 302Bqkg(-1) for 228Th. Long term exposure due to successive fertilizer applications was evaluated. Internal doses due to the application of phosphate fertilizer for 10, 50 and 100 years were below 1mSvy(-1), showing that the radiological impact of such practice is negligible.

Brazil↗
PubMed1997

Dentin demineralization: effects of dentin depth, pH and different acids.

OBJECTIVES: This investigation sought to determine: 1) if dentin demineralization rates are proportional to acid concentration for demineralization in phosphoric acid (10% or 1.76 M, 0.025 M, 0.0001 M, with pH = 0.95, 2.0, 4.0 respectively); 2) if the etching characteristics are independent of dentin depth; and 3) if the etching characteristics for phosphoric acid were comparable to those for citric acid over a similar pH range. METHODS: Highly polished dentin disks from freshly extracted, non-carious, third molars were prepared with a reference layer. Samples were prepared from either superficial or deep coronal dentin. The samples were etched for periods of up to 30 min using phosphoric acid solutions (pH = 0.95, 2.0, 4.0) in a wet cell of an atomic force microscope (AFM). Depth changes with respect to the reference layer were determined for the intertubular and peritubular dentin to quantify structural changes. The results were compared with similar studies using citric acid (pH = 1.0, 2.15 or 3.4). Etching characteristics were statistically compared using 2-way repeated measures ANOVA at p < 0.05 and the Tukey's multiple comparison test. RESULTS: The relation between time and recession for peritubular dentin was initially linear. The intertubular dentin recession started rapidly but then reached a plateau within a very short interval for etching solutions at pH = 2.0 and 4.0. At the highest concentration, the recession decreased with time, but a clear plateau was not established. There was no statistical difference between peritubular etching rates of superficial and deep dentin surfaces with phosphoric acid at any concentration. There was also no difference in the intertubular dentin recession at the location of the plateau that depended on dentin depth. Etching rates increased dramatically with decreased pH for both phosphoric and citric acids, but were higher for citric acid than for phosphoric acid. SIGNIFICANCE: The AFM allowed quantification of changes during etching of wet dentin. Peritubular dentin etching rates increased with decreasing pH, as expected, but changes were not linear and were different for the two acids studied over a similar pH range. Intertubular dentin surface recession was small and plateaued for low concentrations. The peritubular etching rate and intertubular dentin recession did not depend on dentin depth.

Acid Etching, Dental↗
PubMed1990

[Relationship between length of resin tag and bond strength of bonding adhesive].

It is well known that the bond strength of direct bonding adhesive to etched enamel is dependent upon the formation of resin tags. So it is considered that there is a significant correlation between the bond strength and the length and shape of resin tags. However, there are very few reports on this correlation. In this study, a method of combining halogenated methacrylate and electron-probe microanalyzer (EPMA) was applied for measurement of resin tag length in order to investigate the correlation between the bond strength and resin tag length. Two experimental light cured adhesives were prepared for this study. One (CI-U) was prepared by blending microfiller (30 wt%) to the mixture of di (1-methacryloyl-oxyethyl-2-chloromethyl)-2,2,4-trimethylhexamethylene dicarbamate (50 wt%) and triethylene glycol dimethacrylate (TEGDMA: 59 wt%) and the other (Br-B) was prepared by blending microfiller (30 wt%) to the mixture of Bis-GMA (22.2 wt%), TEGDMA (65.9 wt%) and tetrabromobisphenol-A-glycidyl methacrylate (4Br-Bis GMA: 11.9 wt%). Preparation of 2%, 10%, 37%, and 60% phosphoric acid solutions, 2%, 5%, 10%, and 30% maleic acid solutions and 2%, 5%, 10%, and 30% citric acid solutions was carried out for use as etchants. The consistency and the bond strength to etched enamel for the adhesives and the amount of decalcification for the etchants were measured. The etched enamel surfaces, the resin tags on resin surfaces and the interfaces between the resin and enamel were observed with a SEM. The results were as follows: 1) The consistency of Cl-U was higher than that of Br-B. 2) The amount of decalcification was proportional to acid concentration, except for phosphoric acid solution. The amount of decalcification decreased in the order of citric acid solution, maleic acid solution and phosphoric acid solution when the concentration was 2% and 10%. 3) The SEM micrographs revealed that the enamel surface treated with the etchants containing a high concentration of acid was rougher. 4) The bond strength increased with increasing the concentration of the etchants except for the bond strength of Cl-U after being immersed in 37 degrees C water for 30 days and being thermal cycled. The bond strength for Cl-U was reduced greater than that of Br-B by long-term water immersion and thermal cycling.(ABSTRACT TRUNCATED AT 400 WORDS)

Acid Etching, Dental↗
PubMed2005

Raman spectroscopic study of noncarious cervical lesions.

The surface of noncarious cervical lesions (NCCLs) consists of sclerosed dentin. This type of dentin may affect the ability of adhesive restorative materials to bond well to its surface, but little information exists on the chemical nature of this dentin surface and how it may be affected during acidic treatment. The inorganic part of normal dentin and dentin from NCCLs before and after acid conditioning with phosphoric acid or polyacrylic acid was investigated. Ten premolars with NCCLs and four human third molars (control) were used. Replicas of NCCLs were examined using scanning electron microscopy (SEM). Surfaces and longitudinal sections of four NCCLs and control dentin discs were analyzed using Raman spectroscopy. The discs and NCCLs were sectioned, and treated with 35% phosphoric acid or 20% polyacrylic acid/3% aluminum chloride, and Raman spectra obtained. The area under phosphate nu1 of the dentin spectrum was computed to obtain a ratio with the area under the second-order spectrum of a silicon phonon comparative standard. Mean phosphate nu1 and silicon phonon ratios from normal dentin and NCCLs were compared using a linear model with repeated measurements and Tukey's pairwise tests. Mean ratios from different locations of the NCCLs were compared using one-way analysis of variance (ANOVA) and Tukey's pairwise tests. SEM micrographs of NCCL surfaces showed variation from relatively smooth with no dentinal tubule openings to surfaces with occluded tubules. The mean phosphate nu1 and silicon phonon ratios for NCCLs were higher than those of normal dentin in all treatment groups (P < 0.05). Ratios from the untreated specimens were higher than those of the polyacrylic acid-treated specimens, and those for the phosphoric acid-treated group were the lowest (P < 0.05). The ratios obtained for the surfaces of NCCLs were higher than those halfway towards the pulp, and those adjacent to the pulp were the lowest (P < 0.05).

Acid Etching, Dental↗
PubMed2004

In vitro testing of all-in-one adhesives as fissure sealants.

PURPOSE: To evaluate the clinical efficacy of all-in-one adhesives as fissure sealants. METHODS: Resin-enamel bonded specimens were fabricated between polished and ground enamel surfaces using two all-in-one adhesives (One-Up Bond F and Xeno CF Bond) and two resin sealants (Teethmate F-1 and Helioseal F). Specimen beams were prepared and microtensile bond tests were performed at a crosshead speed of 1 mm/minute. The bond strengths obtained were subjected to one-way ANOVA and Scheffe's F test (P < 0.05: n=12 for each group). To evaluate the etching effect of phosphoric acid and the all-in-one adhesives, the treated enamel surfaces (37% phosphoric acid, 40% phosphoric acid, or all-in-one adhesives) were examined by FE-SEM. RESULTS: The bond strengths of the two all-in-one adhesives tested to the polished enamel surface were significantly lower (P < 0.05) than to ground enamel. However, no significant differences (P > 0.05) were found between the polished and ground enamel surfaces for resin sealants using phosphoric acid. Under SEM examination, 37% or 40% phosphoric acid etched the enamel surface more than all-in-one adhesives.

Acid Etching, Dental↗
PubMed2003

Effects of different acid and sodium hypochlorite treatments on dentin collagen: a FEISEM analysis.

PURPOSE: To evaluate if different acid treatments of dentin surface might remove different amount of mineralized dentin, thus exposing and modifying the CF network. METHODS: Dentin disks prepared from human third molars with a low-speed diamond saw were etched for 15 seconds with the tested acids: citric acid 10%, maleic acid 10%, 2.5% oxalic acid, 35% phosphoric acid and 24% EDTA gel. Specimens were then submitted to a 5% solution of NaOCl for 2 minutes or 5 minutes, fixed, and observed utilizing a field emission in lens SEM (FEISEM). Control specimens were also prepared by omitting the etching agent and/or the NaOCl solution. RESULTS: The different acid treatments created specific dentin morphological pattern. CF exposure was in relationship with the acid used. The NaOCl solution greatly affects the acid etched dentin by removing the CF, nevertheless the effect of NaOCl was greatly influenced by the previous acid treatment.

Acid Etching, Dental↗
PubMed1998

The effect of pretreatment with an oxalic acid solution on marginal adaptation to enamel in vivo.

STATEMENT OF PROBLEM: New acids such as oxalic acid have been introduced as a conditioning agent in the total-etch technique. There is concern about long-term retention of the acid on enamel in relation to the superficial etch effect. PURPOSE: This in vivo study evaluated the marginal adaptation to enamel conditioned with either and oxalic acid solution or a phosphoric acid with SEM replica technique. MATERIAL AND METHODS: Twenty-four patients received one of each of three class III restorations. Two cavity preparations were pretreated with aluminum nitrate/oxalic acid/glycine solution 1 of the Gluma 2000 system. The first cavity was primed and sealed with Gluma 2000 solution 2, the second cavity with Gluma 3 and 4. The third cavity was conditioned with phosphoric acid (Gluma 1) and sealed with the bonding resin Gluma 4. All three cavities were restored with a hybrid resin composite (Pekafill). At baseline and after 1 year, replica impressions were made to study the margins with SEM. Semiquantitative analysis of the enamel interfaces was performed (x200 and x1000 magnifications). Marginal quality of the three restorative systems were compared and tested intraindividually. RESULTS: The three restorations exhibited good enamel marginal adaptation and a high percentage of gap-free margins at baseline, 96% to 97% of the total length of margins investigated. Marginal quality decreased significantly after 1 year for all three groups. Gap-free margins were observed in 81% to 85% of the marginal length. No significant differences were found among the groups. CONCLUSION: Despite a less pronounced etch pattern created by conditioning of enamel with the oxalic acid solution, a good enamel marginal quality was observed at both evaluation times, comparable to the marginal adaptation of the phosphoric acid conditioned cavities.

Acid Etching, Dental↗
PubMed2000

The air-abrasion technique versus the conventional acid-etching technique: A quantification of surface enamel loss and a comparison of shear bond strength.

The purpose of this study was to quantify the surface enamel loss that results when an air-abrasive technique is used and to compare the shear bond strength of different prebonding and bonding methods. Enamel loss was determined for 2 enamel-conditioning methods: acid etching with 37% phosphoric acid; and sandblasting with 50 microm aluminum oxide particles under different conditions. A profilometer was used to determine the surface enamel loss. Forty-two bovine teeth were divided into 7 groups (N = 6). The statistical comparison of the different groups was carried out by analysis of variance. The results showed that under certain conditions the enamel loss associated with sandblasting is equal to or smaller than that resulting from acid etching. In addition, the effectiveness of different prebonding and bonding techniques used in the bonding of orthodontic brackets was evaluated by means of shear bond strength measurements. For bonding, 1 resin and 1 glass ionomer cement were evaluated; for prebonding, a sandblaster, 2 different polyacrylic acids and phosphoric acid were tested. Seventy bovine teeth were divided into 7 groups (N = 10) and then stored in water for 24 hours. An Instrom testing machine was used to determine bond strengths, and the 7 groups were compared by means of analysis of variance. The significance of post hoc tests was predetermined at P <.003. The results showed that the bond strength of the sandblasted groups was significantly lower than that of the etching groups. This indicates that sandblasting is not an alternative for the acid-etching technique currently used in orthodontic practice.

Acid Etching, Dental↗
PubMedDate not supplied

The effect of surface treatment on the bond strength of resin composite to dentin.

The purpose of this study was to investigate the effect of various dentin acid treatments on the tensile bond strength of resin composite to dentin, mediated by Prisma Universal Bond 2. Acid solutions (maleic acid, Na-EDTA, phosphoric acid, citric acid/ferric chloride) were applied to dentin surfaces for 15 seconds or 60 seconds, and tensile bond strengths evaluated. For all acids, there was a significant difference in bond strength for the two treatment times; for phosphoric acid and citric acid/ferric chloride, the 15-second application resulted in a higher bond strength, while the reverse was true for Na-EDTA (sodium-EDTA) and maleic acid. The highest bond strength (19.6 MPa) was associated with 15-second citric acid/ferric chloride application, and the lowest bond strength (5.6 MPa) with 60-second application of citric acid/ferric chloride. The bond strengths with 60-second citric acid/ferric chloride (5.6 MPa), 15-second Na-EDTA (5.8 MPa), and 60-second phosphoric acid (6.3 MPa) were not significantly different from the control (5.7 MPa).

Acid Etching, Dental↗
PubMed1994

Altered tissue contribution to interfacial bond strength with acid conditioned dentin.

PURPOSE: To measure the shear bond strength of resin composite to dentin using three fourth generation bonding agents in combination with three different acid treatments. One such treatment was followed by sodium hypochlorite. The purpose was to determine the contribution which the collagen rich, demineralized zone made to bond strength. MATERIALS AND METHODS: Three groups, representing (1) All Bond 2/BisFil, (2) Optibond Dual Cure/XRV and (3) Scotchbond Multi-Purpose/Z100, contained four sub-groups each comprised of 10 caries-free molar teeth whose dentin was exposed in a transverse mid-coronal plane. Dressed with 320 grit, wet silicon carbide paper, the dentin surface in each sub-group was conditioned with 10% maleic acid (15 seconds), 10% phosphoric acid (20 seconds), 2.5% nitric acid (60 seconds) and 10% phosphoric acid (20 seconds) followed by 5% sodium hypochlorite (120 seconds). The bonded resin composite assemblies were stored in water at 37 degrees C for 24 hours and then subjected to shear force at a crosshead speed of 5 mm/minute until failure. RESULTS: The mean and standard deviation values derived for the groups were not statistically different from each other (P < 0.05). It was concluded that the type of conditioning agent was not a factor in achieving optimal bond strength for the system tested. Furthermore, it was tentatively concluded that the collagen-rich zone offered no direct, quantitative contribution to the interfacial bond strength which is probably derived from complete resin diffusion into the porous, partially demineralized dentin below.

Acid Etching, Dental↗