Top PDF Effect of surface removal following bleaching on the bond strength of enamel

Effect of surface removal following bleaching on the bond strength of enamel

Effect of surface removal following bleaching on the bond strength of enamel

Forty-eight specimens were prepared from freshly extracted bovine incisors. The bovine teeth were collected as anonym- ous by-products of regular slaughtering of the cattle for hu- man food consumption. Enamel blocks (4 mm × 4 mm × 4 mm) were cut from the middle third of the buccal surfaces using a low speed diamond saw (Isomet, Buehler, Lake Bluff, IL, USA) under water cooling. The enamel blocks were fur- ther embedded in acrylic resin (ZiRan, Nissin, Hangzhou, Zhejiang, China) using a polyvinylchloride ring mold of a diameter of 10 mm. After ultrasonically cleaning in distilled water for 1 min, the specimens were randomly divided into 2 groups of 24 specimens each, according to the bleaching treatment performed.
Show more

6 Read more

The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel

The Effect of Four Surface Treatment Methods on the Shear Bond Strength of Metallic Brackets to the Fluorosed Enamel

by acid groups compared with acid alone in our study might be attributed to the acid resistant layer created in enamel surface after laser application as indicated in some investigations. [30-31] Some studies suggested that laser ablation could create modifications in chemi- cal and crystalline structure. Reduction of carbonate amends the crystalline structure and subsequently caus- es resistance of enamel to acid dissolution. [30-31] This may be a factor for lower bond strength in laser-acid etch groups compared with acid etch groups. Although, Apel et al. [32] and Chimello et al. [33] found that enamel demineralization was not significantly different between Er:YAG laser and unlased teeth. Another ex- planation was presented by Ferreira et al. [24] who con- cluded that the residual thermal energy after Er:Yag laser-irradiation could change the structure of tooth sur- face by melting and packing the tooth components simi- lar to that of glazing, and this change remained even after different acid etching times. [24] In contrast to our results, Dunn et al. [34] showed that laser followed by acid created better etch pattern and this pattern could be more effective for bonding. The histological investiga- tion showed that different energies of Er:YAG laser could affect the quality of the resultant etched surface. [20] Therefore, the energy employed in different studies. [23-34] may be a causing factor for different results.
Show more

9 Read more

In-Vitro Evaluation of the Effect of Herbal Antioxidants on Shear Bond Strength of Composite Resin to Bleached Enamel

In-Vitro Evaluation of the Effect of Herbal Antioxidants on Shear Bond Strength of Composite Resin to Bleached Enamel

[13-17], one study showed that sodium ascorbate had the potential of forming a three-dimensional, porous physical scaffold that would entrap the pathogenic microorganisms like Streptococcus mutans and this adverse property affected its efficacy for enhancing the bond strength and highlighted the need for other antioxidants [18]. Grape seed as an herbal antioxidant contains pro- antioxidant compounds and is capable of eliminating free radicals [3]. Studies have shown that polyphenols present in green tea are rapidly metabolized and show antioxidant activity [19,20]. Catechins present in green tea such as epigallocatechin gallate (EGCG) are antioxidant compounds that can eliminate free radicals as well [21]. Sage extract also has antioxidant capacity [22]. Previous studies have shown that these herbal antioxidants can reverse the decreased bond strength of composite to bleached enamel [17,22,23]. However, some studies have reported different efficacy values for herbal products in various application times [24-28]. Also, a large number of studies have compared only one or two herbal antioxidants with sodium ascorbate [23,26,27]. In order to better assess the efficacy of herbal and chemical antioxidants, this in-vitro study was carried out to assess the effect of sodium ascorbate, grape seed, sage and green tea extracts on the bond strength of composite to bleached enamel.
Show more

8 Read more

Effect of Three Different Antioxidants on Shear Bond Strength of Composites To Bleached Enamel - An In Vitro Study

Effect of Three Different Antioxidants on Shear Bond Strength of Composites To Bleached Enamel - An In Vitro Study

Perhydroxyl radicals are not only associated with high permeability and diffusibility but also split the long chained, dark colored macromolecules of pigments into smaller, less colored and more diffusible molecules which are removed from the structure producing the bleaching effect. Following bleaching, these free radicals react with the organic enamel and can result in morphological alterations, surface irregularities and reduced bond strength of composite resin to enamel.

5 Read more

Effect of Different Surface Treatments on Microtensile Bond Strength of Composite Resin to Normal and Fluorotic  Enamel after Microabrasion

Effect of Different Surface Treatments on Microtensile Bond Strength of Composite Resin to Normal and Fluorotic Enamel after Microabrasion

In normal teeth, it seems that reduction of enamel surface after microabrasion improved the bond strength to the level of not-abraded enamel. In fluorotic teeth, grinding the micro-abraded enamel improved the bond strength but not to the level of not-abraded enamel. It seems that in fluorotic teeth, the subsurface porosities are so deep that they cause the compaction of microabrasion by-products deep into the enamel surface and reduce the bond strength of composite resin to micro-abraded fluorotic enamel in comparison to non-abraded enamel surface. In normal teeth, no significant difference was detected between the two methods of surface treatment (grinding and extended etching time) in improving the tensile bond strength. But, in fluorotic teeth, grinding improved the bond strength of composite resin significantly greater than extending the etching time. The initial effect of phosphoric acid on enamel etching is to remove 10µm of superficial enamel. The differential dissolution of enamel rods and inter- rods forms 20µm-deep micromechanical retentions [15]. Since microabrasion forms a 15- 20µm thick layer on enamel surface [5], it seems that extending the etching time cannot thoroughly eliminate this layer resulting in lower bond strength in comparison to grinding of fluorotic teeth.
Show more

7 Read more

Effect of enamel protective agents on shear bond strength of orthodontic brackets

Effect of enamel protective agents on shear bond strength of orthodontic brackets

containing 5% sodium fluoride. Fluoride was found to be effective in reducing the development of white spot le- sions associated with fixed orthodontic treatment [16,24]. Also, ICON resin infiltration was found to de- crease the dissolution of enamel and so limit the appear- ance of white spot lesions [25]. When is the proper timing to apply these materials to get the best result of decreasing the white spot lesions around the orthodontic brackets is a worthwhile question. These preventive agents could be applied after bonding the orthodontic brackets, but this may not be easy all the times especially where there are severely crowded or partially erupted teeth. The other option is to apply these materials before bonding the orthodontic brackets, but these preventive agents could have an effect on the shear bond strength and/or the amount of adhesive left on the teeth after debonding of the orthodontic brackets upon treatment completion.
Show more

6 Read more

Effects of at-home and in-office bleaching on the shear bond  strength of metal, ceramic and composite brackets to enamel: An In vitro study

Effects of at-home and in-office bleaching on the shear bond strength of metal, ceramic and composite brackets to enamel: An In vitro study

31 The purpose of this study was to determine the effects at home and in office bleaching on the shear bond strengths of metal, composite and ceramic brackets bonded with light cure composite material to human enamel and to compare the shear bond strengths of metal, ceramic and composite brackets after at-home and in-office bleaching. Descriptive statistics, including the mean, standard deviation, and minimum and maximum values, were calculated for each group. The data is expressed in MEAN ± SD. Statistical Package for Social Sciences (SPSS 16.0) version was used for statistical analysis. One way ANOVA was applied for analysis. Post Hoc followed by Dunnet t test was used to find statistical significance between and within the groups. P value less than 0.05 (P<0.05) considered statistically significant at 95% confidence interval.
Show more

111 Read more

Effect of Addition of Curcumin Nanoparticles on Antimicrobial Property and Shear Bond Strength of Orthodontic Composite to Bovine Enamel

Effect of Addition of Curcumin Nanoparticles on Antimicrobial Property and Shear Bond Strength of Orthodontic Composite to Bovine Enamel

Researchers have long been in search of methods to prevent enamel demineralization during orthodontic treatment without adversely affecting the bond strength [19,20]. Addition of nanoparticles to composite resin has been documented as an effective strategy to prevent enamel demineralization [21,22]. Advancements in nanotechnology have enabled the fabrication of nanoparticles with improved properties. However, aside from their antimicrobial efficacy, their effects on physical and mechanical properties of orthodontic composites must be evaluated [23]. Optimal antimicrobial activity of curcumin has been documented against Enterococcus faecalis [16] and S. mutans [24]. The cariostatic effect of curcumin is mediated by prevention of bacterial adhesion to enamel and destruction of bacterial cell wall via disrupting the peptidoglycan layer [24].
Show more

10 Read more

Effect on enamel shear bond strength of adding microsilver and nanosilver particles to the primer of an orthodontic adhesive

Effect on enamel shear bond strength of adding microsilver and nanosilver particles to the primer of an orthodontic adhesive

Based on our in vitro results, neither SBS nor ARI scores were significantly affected by the addition of microsilver or nanosilver particles of different sizes. Ahn et al. [20] added 250 ppm and 500 ppm of silver nanoparticles with a size smaller than 5 nm in combination with nanosized silica particles to self-mixed experimental composite ad- hesives. They found that SBS values measured on human premolars did not significantly differ between the experi- mental composite adhesives and conventional adhesives. Although we added silver nanoparticles more extensively and at greater concentrations than Ahn et al. [20], we found that our SBS results were comparable with theirs [20]. Following our experimental procedure, Akhavan et al. [21] added silver nanoparticles to Transbond™ XT primer; however, they used higher concentrations (1%, 5% and 10%) of silver nanoparticles and added 5% hydroxyapatite to the mixtures. Furthermore, they mea- sured SBS on human premolars with a crosshead speed of 0.5 mm/min making it impossible to compare their SBS values with ours [35]. Sadat-Shojai et al. [36] de- scribed the influence on bond strength of nanoparticles incorporated into dentin bonding materials. SBS increased with the incorporation of 0.2% hydroxyapatite nanoparti- cles and later decreased at higher concentrations [36]. The Table 3 Adhesive remnant index (ARI)
Show more

9 Read more

The Effect of Aloe Vera, Pomegranate Peel, Grape Seed Extract, Green Tea, and Sodium Ascorbate as Antioxidants on the Shear Bond Strength of Composite Resin to Home-bleached Enamel

The Effect of Aloe Vera, Pomegranate Peel, Grape Seed Extract, Green Tea, and Sodium Ascorbate as Antioxidants on the Shear Bond Strength of Composite Resin to Home-bleached Enamel

In this experimental study, 60 recently extracted sound human maxillary incisors were collected and randomly divided into 6 groups (n=10). The tooth roots were em- bedded in cylindrical acrylic resin blocks (1.5×2.5 cm), with only the tooth coronal portion (above the ce- mentoenamel junction) out of the block. The labial enamel surfaces of samples (6×6 mm) were polished with silicon carbide paper of 600 grit size (Moyco Pre- cision Abrasives; Montgomeryville, PA, USA). The prepared labial surfaces of all the teeth were bleached with 15% carbamide peroxide gel (Opalescence; 15% PF, Ultradent Product Inc, South Jordan, UT, USA) for 6h/day for 5 days. After completion of daily bleaching procedures, the teeth were rinsed with water spray for 1 minute and then kept in distilled water at room tempera- ture until the next day.
Show more

6 Read more

Evaluation of the Effect of Propolis Nanoparticles on Antimicrobial Properties and Shear Bond Strength of Orthodontic Composite Bonded to Bovine Enamel

Evaluation of the Effect of Propolis Nanoparticles on Antimicrobial Properties and Shear Bond Strength of Orthodontic Composite Bonded to Bovine Enamel

enamel surface preparation techniques, various adhesive systems, and bracket-related factors such as area and design of the bracket base [5,6]. Recent studies have shown that 50% to 75% of patients, experience demineralization of dental surfaces during fixed orthodontic treatment [7,8]. An increase in Streptococcus mutans (S. mutans) and Lactobacillus count has been reported in the oral cavity after the placement of fixed orthodontic appliances [9]. Fixed orthodontic treatment makes oral hygiene maintenance difficult and increases plaque accumulation around brackets and bands, leading to an increased risk of dental caries and formation of white spot lesions (WSLs) [10-12]. In addition, enamel etching weakens the structure of the enamel by decalcification and increases the risk of decays [13]. WSLs result from bacterial activity. S. mutans has been associated with decay and plays a major role in the onset of decays [14].
Show more

9 Read more

Effect of Quaternary Ammonium Salt on Shear Bond Strength of Orthodontic Brackets to Enamel

Effect of Quaternary Ammonium Salt on Shear Bond Strength of Orthodontic Brackets to Enamel

In this in vitro, experimental study, sample size was calculated to be 12 in each of the four groups for assessment of shear bond strength according to a previous study by Li et al, [9] assuming alpha=0.05, beta=0.2, effect size of 0.57 and standard deviation of 2.5 using one-way ANOVA. The current investigation was approved by the ethics committee of Tehran University of Medical Sciences (IR.TUMS.REC 1395.2909). The QAS compound that was synthesized and used in this study was methacryloxyethyl cetyl dimethyl ammonium chloride, which was added to Transbond XT light-cure adhesive primer (3M Unitek, Monrovia, CA, USA) [10]. Table 1 lists the constituents of primer and composite resin used in this study. A control group of pure primer was also considered.
Show more

6 Read more

Effect of waiting time for placing resin composite restorations after bleaching on enamel bond strength

Effect of waiting time for placing resin composite restorations after bleaching on enamel bond strength

The SBS of each specimen was tested as previously described [19]. Briefly, a thin metal wire was looped around each composite cylinder and subjected to a shear load using a mechanical testing machine (DL500; EMIC, São José dos Pinhais, PR, Brazil) at a cross- head speed of 1 mm/min until failure. SBS data were expressed in MPa. Data were sub- mitted to a One-Way Analysis of Variance and Tukey’s test (α  = 0.05) using SigmaPlot v.12 software (Systat Software Inc., San Jose, CA, USA). For fracture mode analysis, each specimen was observed at 20× magnification under a light stereomicroscope, and the failure modes were categorized as adhesive (failure at the composite-enamel interface), cohesive in enamel, or mixed failure.
Show more

7 Read more

Comparison of Shear Bond Strength of Different Orthodontic Metal Bracket-bases Bonded on Enamel Surface – an In vitro Study

Comparison of Shear Bond Strength of Different Orthodontic Metal Bracket-bases Bonded on Enamel Surface – an In vitro Study

The shear bond strength also depends on the adhesive materials. Transbond XTTM is one of the most recommended products in current orthodontics. It has been a part of various comparative adhesion studies. In this study, all data were obtained with Transbond XTTM, which strongly associated with previous studies [26-29]. Reynolds and von Fraunhofer [30] stated that all the retentive designs used in the brackets tested should have an acceptable bond force levels (6– 8 MPa). However, there are various factors related to an oral environment or moisture contamination that may affect the shear bond strength. The moisture contamination of bracket- bases with water, saliva and blood has been shown to adversely affect the shear bond strength due to deposits of an organic adhesive layer immediately after exposure that is resistant to washing and subsequently it reduces the shear bond strength of brackets [17,31-33]. Ahmad Sheibaninia et al. [34] evaluated the effect of an acidic food simulating environment on shear bond strength of self-ligating brackets and stated that the margins of bracket-bases allows an acidic food to penetrate, which gradually decreases the shear bond strength. So care should be taken in predicting the results to those conditions. Arunima Goswami [35] et al. stated that moisture contamination did not affect the shear bond strength. It has been suggested that an adverse effect of moisture contamination on orthodontic bonding can be associated with water adsorption, which produce formaldehyde
Show more

9 Read more

Effect of surface protection associated to different bonding protocols on the bond strength to eroded dentin

Effect of surface protection associated to different bonding protocols on the bond strength to eroded dentin

erosion, such as the use of the glass-ionomer sealant (Austin, 2011; Zhou, 2012). Studies have shown that glass-ionomer- based materials have good remineralizing ability due to the action of calcium and great potential for fluoride release (Zhou, 2012; Elkassas, 2014). However, there is a question to be answered which concerns the interference of the residual sealant on the bonding capacity to dentin if the preventive method was not sufficient to stop the loss of substance and a subsequent adhesive restoration may be necessary. Dentin erosion presents specific histology, since the progression of the demineralization is mediated by the presence of the demineralized organic matrix (DOM). If this organic matrix is affected by enzymes and by chemical degradation, the progression of the loss of structure increases over time, so its preservation is extremely important (Zarela, 2015; Comar, 2015). However, the demineralized organic matrix may generate a substrate of difficult bonding, since the exposed collagen may be inadequately infiltrated by the resinous monomers. This fact may affect the durability of adhesive restorations performed to rehabilitate sequelae left by corrosion (Hebling, 2005). The selection of materials that promote efficient adhesion to different substrates, such as enamel and dentin, is an important challenge for restorative dentistry. Traditionally, enamel adhesion is considered safe and reliable, however, bonding in dentin is less predictable and more complex due to its histological differences (Manfroi, 2016). Considering the individuality of each substrate, a new adhesive system, classified as "multi-mode" or "universal", has been recently launched. It promises superior results due to its versatility in relation to the adhesive technique (self-etching or etch-and-rinse). However, there is still no consensus about the best technique for the use of this adhesive on the dentin substrate and not much is known about its performance on the eroded substrate. Finally, it is not clear whether the use of protease inhibitors to maintain the demineralized organic matrix would help increasing the bonding stability when using such systems. Therefore, the aim of the present study was to evaluate the effect of previous dentin protection with glass- ionomer sealant associated with different adhesive protocols in the bond strength to eroded dentin. The null hypotheses tested are that there is no influence of the surface protection method, and the way of application of the adhesive system in the immediate and long-term bond strength to eroded dentine.
Show more

7 Read more

The effects of different irrigation solutions on the bond strength of cemented fiber posts

The effects of different irrigation solutions on the bond strength of cemented fiber posts

The crowns were sectioned 2 mm incisal to the cemento enamel junction (CEJ) with a diamond bur at high speed under water-cooling. The working length was determined by using a size 10 K hand file (Dentsply; Maillefer Instruments, Ballai- gues, Switzerland) then subtracting 1 mm from the total length to preserve the apical foramen. Sequential hand filing up to size 25 was used to enlarge the canal space in conjunction with 2 mL of 6.15% NaOCl irrigant solution between each file size. ProFile series 29 system (Dentsply Tulsa Dental, Chattanooga, TN, USA) was used in a crown down sequence (0.46, 0.36, and 0.27) repeatedly until achieving a master apical file (MAF) of 0.46. Once the MAF was achieved, a final flush with 2 mL of 17% EDTA for 20 seconds was then used to irrigate the root canal. The canals were dried with paper points, and coated with AH-26 sealer (Dentsply DeTrey, Konstanz, Germany) by using a 20 K file rotated counter-clockwise. A gutta-percha master cone coated with AH-26 sealer was condensed into the canal using an endodontic condenser and plugger.
Show more

10 Read more

<p>Is buffalo enamel a suitable substrate for bond strength tests?</p>

<p>Is buffalo enamel a suitable substrate for bond strength tests?</p>

strength test values is dubious due to the variability of methods and devices used, and although these tests are not sufficient to determine the clinical success of a particular product or technique, evidence has shown that the perfor- mance of the materials can be initially evaluated through such in vitro tests. The rapid technological progress in adhesive materials makes their evaluation in primary stud- ies essential, so they can progress to clinical trials and use. For example, if a restorative material does not prove to be effective upon controlled laboratory conditions, it might not work well when exposed to the more complex oral environment. 3,17
Show more

7 Read more

The effect of green tea on the shear strength of brackets after home whitening treatment

The effect of green tea on the shear strength of brackets after home whitening treatment

The diverging results between studies testing antioxidants versus the reversal of bond strength values can be attributed to the different methods used in the studies. Kimyai et al. [13] applied sodium ascorbate in the form of hydrogel or solution for 10 min or 3 h, and found that the application for 3 h obtained similar results to those of the present study, which used an application time of 1 h. In the study by Bulut et al. [6, 7], sodium ascorbate solution was stirred on enamel surface during the 10-min application time, which may have increased its effectiveness. In the present study, a small amount of green tea or sodium ascorbate was placed on the enamel surface by using individual impres- sion trays, simulating a possible clinical application.
Show more

7 Read more

Comparison of tensile bond strength of two different resin cements used to bond base metal alloy to human enamel: An In Vitro study

Comparison of tensile bond strength of two different resin cements used to bond base metal alloy to human enamel: An In Vitro study

Various laboratory studies have been done on layer thickness 3 , adherence energy 6 , polymerization shrinkage 60 , and the effect of storage conditions 1 of cast restoration on the bond strength of resin cements. The bond strength of the resin luting cements used to bond the base metal alloy to the tooth structure is an important feature that must be investigated. Comparisons among different studies are complicated because of the different approaches used to test adhesive ability (bonding) of resin cements. Generally, adhesive capacity has been evaluated with invitro testing, with shear and tensile tests. However, finite element analysis 10 concluded that shear test were the most efficient to disclose the cohesive resistance of the material, whereas tensile tests were better to investigate the adhesion at the interface. Since the purpose of this study was to evaluate the adhesive capacity of the resin cement rather than the stress produced during clinical function, a tensile test was used.
Show more

118 Read more

Evaluation of changes in enamel thickness after orthodontic treatment depending on the force applied to remove orthodontic brackets: OCT analysis and universal testing machine

Evaluation of changes in enamel thickness after orthodontic treatment depending on the force applied to remove orthodontic brackets: OCT analysis and universal testing machine

but probably lower concentration. The mode of etching and priming of the 2 bonding systems is different. In our research, the effect of the enamel etching method on its thickness after the completed treatment was evaluated. The studies evaluated the entire tissue subjected to etch- ing, measuring the thickness of the cross-section from the inside to the outer border of the tissue, so it was pos- sible to measure all the layers obtained with OCT im- aging, which after their combination reflected the entire enamel cross-section. The mean enamel thickness after the completed treatment when using the classical etch- ing method was 101.00 μm and in the VII generation sys- tem group – 81.74 μm. However, the differences found were not statistically significant. The results show that enamel thickness after the treatment and its possible dam- age does not depend in any way on the bonding system type. The other authors’ studies suggest a smaller effect of the self-etching system on the enamel, and our experi- ment leads to the conclusion that the effect of both systems on enamel is similar. The difference in results in this re- spect is due to the fact that the methodology of compared studies differs. Our own research focused on the quantita- tive evaluation of enamel, whereas previously presented experiments of other authors such as Retief, 24 Arakawa
Show more

7 Read more

Show all 10000 documents...

Related subjects