Self-etching Primer Research Articles

The effect of multiple enamel conditioning on enamel micro-hardness

White spot formation is one of the common side effects in orthodontic treatments and multiple enamel conditioning might happen even during on session of fixed orthodontic treatments. The aim of the present study was to evaluate the impact of multiple enamel conditioning with different methods on enamel micro-hardness (MH). In this In vitro experimental study, the buccal surfaces of 105 extracted premolars were evaluated in seven groups: One control and six experimental groups. The enamel conditioning was performed in three ways: Etching with phosphoric acid 37%, etching with phosphoric acid 37% followed by primer application and conditioning with self-etch primer. The conditioning process in each way was also performed twice consecutively. The specimens were submitted in pH cycling model with demineralization and re-mineralization solutions for 14 days. Afterward Vickers MH test was applied with 0.981N force on the teeth for 10 s indentation time. Data were analyzed using One-Way ANOVA and Tukey HSD (honestly significant difference) test for multiple comparisons. A value of P < 0.05 was considered statistically significant. MH analysis showed statistically significant differences between the control group and the other conditioned groups (P < 0.05). The groups conditioned with acid-etch and primer, particularly twice, showed the lowest amount of MH in comparison to other groups. Self-etch primer had the least effect on MH of the enamel. Single time etching without using primer, made no considerable difference when compared to multiple etching. Etching process and covering the enamel with primer decrease enamel MH. Using self-etch primer is a more conservative method of enamel conditioning.

Orthodontic bond strength with the use of non-aerosol producing bonding primers in lieu of conventional primers: An in vitro evaluation.

To evaluate the efficacy of non-aerosol producing restorative self-etching primers (SEPs) as a substitute for conventional orthodontic bonding primers and to analyze the extent of residual composite on the tooth post-debonding. Eighty-four extracted human premolars were randomly divided into seven groups based on the adhesive and the bonding protocol used. The study comprised Prime and Bond one select (Dentsply), G-Premio Bond (GC), which were each divided into three subgroups based on the method used for moisture control and the control group (Transbond XT conventional total etch). The three methods for moisture control in study groups were: without drying, air-drying with the use of a three-way syringe, and with the use of blotting paper. Shear bond strength (SBS) was tested using a universal testing machine (UTM), and after debonding, the enamel surface of each tooth was examined under 10× magnification to evaluate adhesive remaining index (ARI) scores. Groups 2A (Prime and Bond; without drying) & 1 (Transbond XT) had the lowest and highest SBS values, respectively (P = 0.001). Comparison of ARI between the control group and group 2b (Prime and Bond; air-drying with 3 in 1) showed a significant difference (P = 0.041). Comparison of ARI between control group and group 2c (Prime and Bond; blotting paper) showed a significant difference (P = 0.017). Rest all other comparisons were non-significant. Transbond XT had SBS values higher than the self-etch groups. Among the self-etch groups, G-Premio Bond had higher SBS values when the traditional methods of air-drying were followed. Use of blotting paper for drying that produced variable SBS values can be an effective alternative method. G-Premio Bond with its adequate bond strength under manufacturer's instruction seems promising in this regard.

19 - Root Dentin Conditioning with Self-Etch Primers Incorporated with Nanochitosan

19 - Root Dentin Conditioning with Self-Etch Primers Incorporated with Nanochitosan

Etching Patterns of Self-Etching Primers in Relation to Shear Bond Strength on Unground Enamel Samples.

It was the intention of the study to evaluate the etching effects of several self-etching primers on unground enamel and their relevance for shear bond strength testing. Seven self-etching primers (Clearfil SE, Futurabond NR, M-Bond, One Coat, Optibond, Transbond SEP+, Xeno III) and a conventional 35% phosphoric gel acid were applied to bovine incisors according to the manufacturer’s instructions. All specimens were analyzed by electron microscopy. A visual four-step grading was used for the characterization of the macroscopic (5000×) and microscopic (20,000×) etching patterns. In addition, shear bond strength for all the products was tested with an Instron 3344 after 1000 thermocycles between 5 °C and 55 °C. Statistical analysis was carried out using Kruskal–Wallis with Dunn’s post-test and Pearson’s correlation coefficient. Very strong etching patterns with well-defined prisms were found for the conventional etching, Transbond SEP+, and to a lesser degree, for Xeno III. Clearfil SE and Futurabond NR revealed moderate etching patterns, and M-Bond, One Coat, and Optibond revealed very weak etching patterns. The bond strength correlated well with the etching patterns. The highest shear strength was obtained with conventional etching and Transbond SEP+, followed by Clearfil SE. Moderate shear bond strengths were found for Xeno III, Futurabond NR, One Coat, and M-Bond, and the lowest were found with Optibond.

Siloranes–Suitability of a Novel Adhesive for Orthodontic Bracket Bonding

Recently, an epoxy-based resin-Filtek Silorane-has been proposed for restorative fillings. It was the aim of the investigation to evaluate the suitability of this novel resin for orthodontic bracket bonding on unground enamel. Shear bond strength was measured for two adhesives-Filtek Silorane, Transbond XT-in combination with steel, ceramic and polymer brackets. For Filtek Silorane etching was performed with the Silorane self-etching primer, as well as phosphoric acid. The Transbond XT samples were etched with phosphoric acid only and served as the control group. All samples were thermo-cycled (1000×, 5–55 °C). Shear testing was carried out with an Instron 3344. In addition, ARI scores were evaluated. The Shear bond strength showed a weak adhesion of Filtek Silorane to unprepared enamel, either with the self-etching primer or the conventional etching (0.87–4.28 MPa). The Shear bond strength of the control group was significantly higher (7.6–16.5 MPa). The ARI scores showed a clear failure at the enamel-adhesive interface for all Filtek Silorane samples. For the combination of Transbond XT and different brackets the failure was found at the adhesive–bracket interface. The novel epoxy-based resin Filtek Silorane is not appropriate for bracket bonding to unprepared enamel.

The Effect of Dentin Treated with Calcium Phosphate Desensitizer on Shear Bond Strength with Different Resin Cement: An In Vitro Study

Aim: The aim of this study was to evaluate the effect of calcium phosphate based desensitizing agent on shear bond strength of self-etch/adhesive resin cements to dentin. Materials and Methods: Eighty dentin specimens were prepared from freshly extracted human third molar teeth and were classified, randomly ( n = 20). Half of groups were treated with calcium phosphate based Teethmate Desensitizer and then Panavia V5, RelyX Ultimate (containing self-etch primer), Panavia SA, and RelyX U200 self-adhesive resin cements were luted to all dentin surfaces. All specimens were stored in an incubator at 37°C for 24 h. Shear bond strength was tested by a universal test machine at a 0.5 mm/min crosshead speed. The data were analyzed with a statistical program. Two-way ANOVA was used for statistical differences ( P &lt;.05). Dentin surfaces were examined with scanning electron microscopy (SEM) at x5000 and x10000 magnifications. Results: The higher shear bond values were observed in the groups with Teethmate Desensitizer applied and cemented with self-etch (16.05 ± 6.24 and 14.73 ± 4.75), whereas the lowest bonding values were observed in the groups with self-adhesive resin cement without Teethmate Desensitizer (3.73 ± 0.77 and 5.85 ± 4.19; P &lt;.001). As the main effect of the treatment, the bond strength was 9.39 ± 6.04 in the control group, whereas it was 13.49 ± 5.44 in the Teethmate applied groups ( P &lt;.05) Conclusions: Calcium phosphate desensitizer did not adversely effected shear bond strength of self-etch/adhesive resin cements to dentin. It even significantly increased the shear bond strength of self-adhesive resin cements.

Comparison between Hydrofluoric Acid and Single-Component Primer as Conditioners on Resin Cement Adhesion to Lithium Silicate and Lithium Disilicate Glass Ceramics.

This study aimed at evaluating the effects of different surface conditionings on the microshear bond strength (µSBS) of a self-adhesive resin cement to VITA Suprinity (ZLS) and IPS e.max CAD (LD). Three surface conditioning protocols were performed on ZLS and LD before luting with a self-adhesive resin cement (RelyX Unicem 2, RXU): hydrofluoric acid (HF), HF + silane (HF + S), or Monobond Etch & Prime (EP). In each group, 15 cylindrical buildups of RXU were prepared on five milled bars and submitted to a µSBS test. Data were statistically analyzed with two-way ANOVA and Tukey’s post hoc test (p < 0.05). Failure modes were recorded and classified as adhesive, mixed, cohesive in resin, or ceramic, and statistically analyzed with Fisher’s exact test (p = 0.05). One additional bar per group was used for the morphological characterization of the conditioned surface by means of SEM. The material per se did not significantly influence adhesion (p = 0.744). Conditioning protocol was a significant factor: EP yielded significantly higher μSBS than HF (p = 0.005), while no significant differences emerged between EP and HF + S (p = 0.107), or HF + S and HF (p = 0.387). The material-conditioning protocol interaction was not statistically significant (p = 0.109). Significant intergroup differences were found in distribution of failure modes: mixed failures were predominant in the ZLS/EP group, while the other groups showed a prevalence of adhesive failures. The self-etching primer showed promising results in terms of immediate bond strength of a self-adhesive resin cement to lithium-silica-based glass ceramics, suggesting its alternative use to hydrofluoric acid and silane conditioning protocols.

PH Evaluation over a Period of 6 months of Two-bottle Water-based Self-etching Primers: An In Vitro Study

The objective of this study was to monitor the pH stability over a period of 6 months of two-bottle self-etching (SE) primers. Four commercially available two-bottle SE primer solutions, Adhese SE (Ivoclar Vivadent; Schaan, Liechtenstein), Clearfil SE (Kuraray; Tokyo, Japan), Contax Primer (DMG; Hamburg, Germany), and Enabond SE (Micerium; Avegno (Ge), Italy), containing water as the main solvent were selected. The pH values during a 6-month storage period at intermittent temperature were daily measured by means of a microprocessor-based pH/temperature meter and hence recorded, tabulated, and analyzed. The mean values of overall pH measurements and standard deviation for Adhese SE, Clearfil SE, Contax Primer, and Enabond SE are, respectively, 1.70 (±0.01), 1.72 (±0.01), 1.20 (±0.01), 1.80 (±0.01). One-way ANOVA did not detect any significant change of the mean pH values of all measurements over time. The conventional 6-months storage did not affect the pH values of the water-containing primers of two-bottle SE adhesives. This study provides evidence that conventional storage under adequate conditions did not affect the pH values of the water-containing primers of two-bottle SE adhesives with different monomer formulations. Clinicians may rely on the known pH value of the selected SE adhesive during shelf-life.

Comparative Evaluation of Shear Bond Strength of Brackets Bonded with self Etch Primer/Adhesive and Conventional Etch/Primer and Adhesive System.

Introduction:The shear bond strength obtained with an acid primer might not be clinically reliable. The present study evaluated the use of a new self-etch primer as compared with the conventional bonding procedure. The findings indicated that the use of a self-etch primer to bond orthodontic brackets to the namel surface provided lower, but clinically accept-able, shear bond forces (mean, 7.1 ± 4.4 MPa). Hence, this study has been designed to evaluate the shear bond strength of orthodontic brackets bonded with a self-etching primer system, and compare it with the conventional acid etching priming system.Materials and Methods:This study was designed to compare the shear bond strength of orthodontic brackets bonded with conventional acid etching- priming and a self-etching primer. For this purpose, one hundred and twenty noncarious, not subjected to any pretreatment chemical agents (e.g. hydrogen peroxide), no cracks caused by the presence of the extraction forceps, no caries and unrestored human maxillary 1st and 2nd premolars, freshly extracted for orthodontic treatment were collected and stored in distilled water before bonding. Separate molds of cold-cure acrylic were prepared and the extracted premolar teeth were embedded in the cold cure acrylic up to the cement enamel junction.Results:For the control group, the mean shear bond strength was 9.38 ± 6.02 MPa and for the experimental group, it is 6.91 ± 3.58 MPa. Group comparison using Chi-square test for the self-etching primer group adhesive remnant index (ARI) scores shows that more than half of the adhesive left over the tooth surface (score 3 and 4). For the conventional group, ARI scores show that there was no or slight amount of adhesive left over the tooth surface (score 5). The proportion of ARI score is significantly (P < 0.001) more in conventional (68.33%) as compared to self-etch primer (SEP) (28.33%). The proportion of ARI scores 4 and less is significantly more in SEP (71.67%) as compared to Conventional (6.67%) with P = 0.004 as per the Chi-square test.Conclusion:The bond strength of SEP is comparatively lesser than the conventional acid etching technique, but is definitely more or less to the required bond strength to resist masticatory forces. Majority of the studies conducted on self-etching primer are in vitro studies. Results of these cannot be extrapolated to the intraoral environment. Hence, further long-term clinical studies need to be carried out before actually recommending the use of self-etching primer in routine orthodontic bonding.

Comparison of the failure rate, bonding time and ARI score of two orthodontic bonding systems: Self-Etch Primer and Conventional Etching Primer: A systematic review and meta-analysis

This study aimed to evaluate the failure incidence of brackets with at least six months follow-up between self-etch primer and conventional etch/primer, as well as to investigate the clinical duration of the bonding process and the amount of adhesive remnant index (ARI). Electronic search was conducted in databases including PubMed, Scopus, Web of Science, ProQuest, ClinicalTrials.gov, and ICTRP (International Clinical Trials Registry Platform). The electronic search targeted only randomized clinical trials and was limited from January 2000 to June 2021. Delphi list is used to evaluate the risk of bias and Stata Version14.2 software was used. This systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and recorded on the Ethics Committee of Research Institute of Dental Sciences, SBMU (IR.SBMU.DRC.REC.1398.240). Out of 2288 extracted studies, 30 of them entered the full-text evaluation process. According to the inclusion criteria, 15 studies entered this systematic review. Containing 607 participants and 10,563 brackets/teeth. All the included studies were of randomized clinical trials (RCT) design with either parallel or split-mouth design. Comparing the two groups, the risk difference effect (RD)=0.007 CI 95% (-0.004,0.018) indicated a neglectable difference in the risk of bracket failure during treatment between the two groups. The index I2=53.9% indicated moderate heterogeneity in the results. Furthermore, the P-value=0.007 indicated statistical insignificance between the two interventions in terms of failure rate. The clinical duration of bonding time analysis were equal to SMD _Cohen=-2.67 CI95% (-3.49, -1.85), which indicated a statistically significant reduction in clinical process time, using the self-etch primer. Data synthesis for adhesive remnant index could not be conducted due to heterogeneity among included studies. There was no difference between the self-etch primer and conventional etch/primer in bracket debonding at a medium level of evidence, However, there was statistically significant reduction in clinical bonding time using self-etch primer.

Effect of using different component combinations for orthodontic bracket bonding with self-etch primers.

To evaluate bonding quality for orthodontic bracket bonding with different component combinations of self-etch primers in vitro. Metallic brackets were bonded to bovine lower incisors and assigned to groups. Group1: comparison of self-etch (Transbond™ Plus, 3M™ Unitek, Neuss, Germany, n = 30; BrackFix® primer SE, VOCO®, Cuxhaven, Germany, n = 20) and etch-and-rinse bonding systems (Transbond™ XT, n = 20; BrackFix®, n = 20); group2: comparison of different self-etch primer (Transbond™ Plus; BrackFix® primer SE) and adhesive (Transbond™ XT, n = 20; BrackFix®, n = 20) product combinations; group3: testing cyclic fatigue bond strength of self-etch bonding systems (Transbond™ Plus, n = 20; BrackFix® primer SE, n = 20). All teeth were tested for shear bond strength according to the DIN-13990 standard, the adhesive remnant index (ARI) and enamel fractures were determined microscopically (10 ×magnification). The mean shear bond strength of the self-etch (Transbond™ Plus: 16.38 ± 3.68 MPa; BrackFix® primer SE: 16.24 ± 1.73 MPa) and etch-and-rinse bonding systems (Transbond™ XT: 18.45 ± 2.56 MPa; BrackFix®: 17 ± 5.2 MPa) were of aclinically adequate order of magnitude (≥ 6-10 MPa) and were not statistically different. The component combination BrackFix® primer SE/Transbond™ XT adhesive led to asignificantly lower shear bond strength (11.99 ± 3.68 MPa). There were no significant differences between static and fatigue shear bond strengths of self-etch bonding systems. Mean ARI scores mostly ranged between4 and5. The combination of the self-etch primer Transbond™ Plus with the BrackFix® adhesive led to asignificantly increased enamel fracture rate. Based on the present findings bond strength of self-etch primers was equal to etch-and-rinse primers for bracket bonding. Combining different self-etch bonding systems might alter the clinical performance.

Shear bond strength of orthodontic brackets bonded with resin coating material

The purpose of this study was to determine whether a system using a resin coating material (PRG Barrier Coat) with anticariogenic ability can effectively bond orthodontic brackets to human teeth. Resin-modified glass-ionomer cement system (Fuji Ortho LC, group 1) and resin composite cement systems (BeautyOrtho Bond) combined with a self-etching primer (group 2), with the resin coating material (group 3), and with the resin coating material after an organic acid etching agent (group 4) were used for bracket bonding. The mean shear bond strength (SBS) was significantly higher in group 1 than in groups 2, 3 and 4. Groups 2 and 4 exhibited a significantly higher mean SBS than group 3. The resin composite cement system combined with the resin coating material after the organic acid etching agent can serve as an alternative for orthodontic bracket bonding.

Bond assessment of enamel conditioned with Er, Cr: YSGG laser and methylene blue photosensitizer activated by photodynamic therapy to orthodontic metallic brackets

AimTo assess bond integrity and failure mode after enamel pretreated with conventional and contemporary conditioning methods were bonded to metallic brackets (MB). Material and methodsForty maxillary central incisors were selected and disinfected. All specimens were mounted up to the cement-o-enamel junction and divided into four experimental groups randomly based on the enamel conditioning technique. Photodynamic therapy (PDT) was used to condition enamel in group 1, Total-etch and rinse (TER) was used to treat samples in group 2, Specimens in group 3 were conditioned with ECL, and samples in group 4 surface pretreated with SEP. Bonding of MB was performed on the surfaces of all the specimens with a Transbond XT. Specimens from all investigated groups were positioned on a universal testing machine maintaining buccal surfaces similar to the direction of the force. After bracket debonding bond failure was assessed using ARI. The bond integrity of all four groups was compared using analysis of variance (ANOVA). Post hoc Tukey test was used for pairwise comparison among different groups. ResultsGroup 2, TER+MB (15.38±0.14 MPa) displayed the highest bond value whereas the lowest values of SBS were exhibited by group 1, PDT+MB (10.11±0.17 MPa). The inter-group comparison revealed that specimens of group 2 and group 3, ECL+MB (14.61±0.55 MPa) demonstrated comparable bond strength (p>0.05). ConclusionEnamel conditioned with TER and ECL demonstrated comparable SBS. However, bond integrity after PDT and SEP (self-etch primer) surface treatment of enamel bonded with MB significantly lowered bond values.

Observational Study Regarding Two Bonding Systems and the Challenges of Their Use in Orthodontics: An In Vitro Evaluation

The purpose of this in vitro study was to analyze and identify a methodology for the improvement of the shear bond strength of orthodontic brackets bonded with two orthodontic adhesive systems considered to be widely used, Transbond Plus Color Change with Transbond Plus Self-Etching Primer and Fuji Ortho LC with orthophosphoric acid under various enamel conditions: dry, moistened with water and moistened with saliva. The sample size included a group of 120 freshly extracted premolars distributed into six study groups, each one of 20 teeth. A universal testing machine was used to detach the brackets. We determined and compared the strength of the two studied adhesive systems used in different enamel surface conditions. The mean shear bond strength values in groups 1 (TPCC, TSEP, dry), 2 (TPCC, TSEP, water), 3 (TPCC, TSEP, saliva), 4 (Fuji Ortho LC, etched, dry enamel), 5 (Fuji Ortho LC, etched enamel, water) and 6 (Fuji Ortho LC, etched enamel, saliva) were 15.86, 12.31, 13.04, 15.27, 14.14 and 13.11 MPa, respectively. ANOVA test and Student’s t-test showed significant differences between groups. While clinically acceptable shear bond strengths were obtained for all six studied groups, a particular outcome that to the authors’ knowledge has not been documented elsewhere has been obtained: in case of water contamination, it is preferable to use Fuji Ortho LC instead of Transbond Plus.

Bis[2-(Methacryloyloxy) Ethyl] Phosphate as a Primer for Enamel and Dentine

Dental resin composites are commonly used in the restorative management of teeth via adhesive bonding, which has evolved significantly over the past few decades. Although current self-etch bonding systems decrease the number of clinical steps, the acidic functional monomers employed exhibit a limited extent of demineralization of enamel in comparison to phosphoric acid etchants, and the resultant superficial ionic interactions are prone to hydrolysis. This study evaluates the etching of primers constituted with bis[2-(methacryloyloxy) ethyl] phosphate (BMEP) of dental hard tissue, interfacial characteristics, and inhibition of endogenous enzymes. We examine the incorporation of 2 concentrations of BMEP in the formulation of experimental primers used with a hydrophobic adhesive to constitute a 2-step self-etching bonding system and compare to a commercial 10–methacryloyloxydecyl dihydrogen phosphate (10-MDP)–containing system. The interaction of the primer with enamel and dentine was characterized using scanning electron, confocal laser scanning, and Raman microscopy while the polymerization reaction between the BMEP primers and hydroxyapatite was evaluated by Fourier-transform infrared spectroscopy. The inhibitory effect against matrix metalloproteinase (MMP) enzymes of these primers was studied and percentage of inhibition analyzed using 1-way analysis of variance and Tukey’s post hoc test (P < 0.05). Results of the scanning electron microscopy micrographs demonstrated potent etching of both enamel and dentine with the formation of longer resin tags with BMEP primers compared to the 10-MDP–based system. The BMEP polymerized on interaction with pure hydroxyapatite in the dark, while the 10-MDP primer exhibited the formation of salts. Furthermore, BMEP primers were able to inhibit MMP activity in a dose-dependent manner. BMEP could be used as a self-etching primer on enamel and dentine, and the high degree of polymerization in the presence of hydroxyapatite can contribute to an increased quality of the resin polymer network, prompting resistance to gelatinolytic and collagenolytic degradation.

Effects of Surface Treatment Procedures on Bond Strength of Lithium Disilicate Glass Ceramic.

To evaluate the microshear bond strength (μSBS) of resin cement to a lithium disilicate glass ceramic conditioned with different surface treatment procedures. Crystallised slices of lithium disilicate glass ceramic were randomly divided into five groups (n = 10) according to different surface treatment procedures: the no surface treatment (NT) group was untreated; the hydrofluoric acid (HF) group was conditioned with 4.5% HF; the silane (S) group was conditioned with a silane coupling agent; the hydrofluoric acid and silane (HFS) group was conditioned with HF followed by the silane coupling agent; and the Monobond Etch & Prime (MEP) (Ivoclar Vivadent, Schaan, Liechtenstein) group was conditioned with the one-step self-etching primer MEP. Resin cement was applied to the ceramic surfaces and irradiated. A μSBS test was performed. Failure analysis, surface roughness tests, surface topography examination and elemental analysis were also conducted. The data were analysed with a one-way analysis of variance (ANOVA) and Tukey honestly significant difference test (P < 0.05). The MEP group resulted in comparable μSBS to the HFS group (16.9 ± 4.3 MPa and 16.0 ± 2.2 MPa, respectively), but a significantly higher μSBS than the NT (1.0 ± 0.9 MPa), HF (8.9 ± 3.9 MPa) and S (12.6 ± 2.5 MPa) groups. Adhesive failure was mainly observed in the NT and HF groups, while the S, HFS and MEP groups demonstrated the most mixed failure. Though micrographs revealed a roughened surface in the HF group, no significant difference was found with any other groups. Within the limitations of this study, it can be concluded that the μSBS of resin cement to lithium disilicate glass ceramic etched with MEP is as efficient as that treated with HF and silane.

Effects of enamel deproteinization with different application times on the shear bond strength of a self-etching primer: An in vitro study

The aim of this in vitro study was to evaluate the effects of enamel deproteinization on the shear bond strength of a self-etching primer Transbond Plus™(TBP), with different application times of sodium hypochlorite (NaOCl 5.25%), primarily and secondarily on the adhesive remnant index score. One hundred twenty-five freshly extracted human premolars were randomly and blindly divided into five groups according to the enamel surface preparation, as follows (n=25): group 1(control): Etching with 37% phosphoric acid for 15seconds+Bonding; group 2 (control): TBP™ without NaOCl, group 3: 60seconds NaOCl+TBP™, group 4: 30seconds NaOCl+TBP™, group 5: 15seconds NaOCl+TBP™. The same composite resin was used (Transbond XT™) to bond the orthodontic metal brackets. After the immersion of the teeth in distilled water at 37°C for 24hours the shear bond strength was measured using the universal testing machine and the adhesive remnant index score (ARI) was evaluated under an optical microscope (25×). The mean SBS values (inMPa) of the groups were respectively: group 1: 13.03±5.36; group 2: 12.28±3.06; group 3: 12.38±4.55; group 4: 12.98±5.76; and group 5: 11.73±5.67. Enamel deproteinization increased the SBS for groups 3 and 4, but no statistically significant difference was found between the five groups (P=0.883). Group 1 showed the highest ARI scores, with 52% of the teeth retaining all the adhesive (score 3). However, for all the other groups, scores 0 and 1 were predominant, with less than half of the adhesive or no adhesive at all remaining on the teeth. Enamel deproteinization with sodium hypochlorite (5.25%) and the variation of its application time has no effect on the SBS of the self-etching primer Transbond Plus ™.

Evaluation of Microleakage under Sapphire Brackets Bonded with Three Different Orthodontic Adhesives after Thermocycling and Water Storage (An in Vitro Study)

Objectives: To evaluate and compare the microleakage between enamel-adhesive, bracket-adhesiveinterfaces at occlusal and gingival sides of sapphire brackets bonded with three different light-cure adhesivesystems after thermocycling and 2 months water storage.Materials and Methods: Sapphire brackets bonded to forty eight intact extracted upper premolar randomlyassigned according to orthodontic adhesive systems used into three equal groups (n=16) with different colorcoding: Conventional Transbond XT; Transbond XT plus self-etching primer; Resin-modified glass ionomercement (RMGIC) GC Fugi Ortho LC. After bonding and thermocycling, half of samples (8 teeth) in eachgroup, tested immediately after thermocycling and 24 hours of water storage and the remaining 8 teeth wereincubated in distilled water to be tested after 2 months of water storage. After each storage interval, sampleswere subjected to a dye penetration test and examined under a stereomicroscope with image analyzersoftware to assess the degree of microleakage in mm. Data was analyzed using the non-parametric tests.Results: After both storage time intervals, RMGIC group displayed higher microleakage than other groupswith high significant differences with Transbond XT group and more microleakage seen at gingival marginthan occlusal margin in all groups. The microleakage values increased after 2 months storage, but withoutsignificant differences.Conclusion: The type of adhesive systems could effect the amount of microleakage and higher valueunder brackets bonded with RMGIC with more microleakage gingivally than occlusally. The microleakageincreased after thermocycling with 2 months water storage.

Evaluation of self-etching primer on bond strength in feldspathic ceramic

The aim of the study was to evaluate the effect of self-etching silane primer on long-term bonding strength on feldspathic ceramic. Ceramic blocks (IPS Empress CAD, Ivoclar Vivadent) were cut with a low-speed diamond disk (Isomet 1000, Buehler) into 40 blocks of 12x7x6mm, under water cooling, and randomly divided into two groups (n=20), according to the surface conditioning: hydrofluoric acid (HF) (Condac, FGM) or self-etching silane primer (MEP) (Monobond Etch and Prime, Ivoclar Vivadent). After the blocks were bonded to composite resin blocks (12 x 7 x 3mm) (Liss, FGM) with a light cured cement (Variolink Esthetic LC, Ivoclar Vivadent) and LED photoactivation (Radii Cal, SDI) for 40 s on each luting interface line. The sets were cut in sticks with 1-mm2 cross-section composed of ceramic/cement/composite and tested after 24h (baseline) and 90 days aging by stored in distilled water at 37ºC. Microtensile bond strength testing (mTBS) was performed using a universal machine (DL-1000, EMIC) submitted to traction with speed of 0.5mm/ min until rupture of adhesion. Fracture of specimens were examined under stereomicroscopy to determine the failure pattern. Bond strength (MPa) was calculated, and the failure pattern and interface topography were assessed using scanning electron microscopy (SEM). No significant different mTBS was observed between groups HF and MEP (p&gt;0.05). Storage time of the samples did not affect the mTBS from the groups. Surface etching pattern with HF produced higher surface alterations than a self-etching primer. Application of MEP may be considered an alternative for silanization for feldspathic ceramic.

EFFECT OF ETCHING TECHNIQUES ON THE SHEAR BOND STRENGTH OF ADHESIVE PRECOATED BRACKETS BONDED IN VITRO

This study was designed to compare shear bond strength durability of two etching techniques namely conventional etching and self-etching primer techniques, when using Adhesive pre-coated brackets (APCII). Thirty extracted premolars were divided into two equal groups (group 1: etched with 37% Phosphoric acid and group 2: bonded with transbond plus self-etching primer), each group was further subdivided into three subgroups each of them contains five teeth, at different storage times: 24 hours, 30 days and 3 months. Universal testing machine was used to measure shear bond strength. T-test revealed that there was no significant difference in shear bond strength between the two etching techniques at 24 hours and 30 days, while showed a highly significant difference (P ≤ 0.01) at 3 months. For the three storage times, self-etching primer showed less adhesive remnant on the teeth than that of Phosphoric acid etching. It can be concluded that self-etching primer provided shear bond strength Comparable to that of phosphoric acid, and it has less adhesive remnant than conventional etching technique.