Differences In Shear Bond Strength Research Articles

Evaluation of shear bond strength of feldspathic porcelain on various laser surface treated cobalt-chromium discs

Brief Background The aim of the study is to compare and evaluate shear bond strength of porcelain fused to metal substructure fabricated using conventional method, surface treated with different laser modalities and direct metal laser sintering. Material and Methods Forty samples made of Co-Cr were fabricated, divided into control (Group A) and three test groups (Group B, Group C, Group D) (n=10 each). Groups A, C, D samples were made by conventional lost wax technique and B by laser sintering. All the samples were sandblasted and group C and D were surface treated with Nd: YAG and Er: YAG lasers respectively. Further, samples were veneered using 2mm of porcelain. The samples were placed in a jig and held in a universal testing machine to test the bond strength between Co-Cr and porcelain. Samples were subjected to shear stress until the fracture occurred and the results were noted. Data analysis was done using one- way analysis of variance and Post-Hoc test. Result The mean shear bond strength was highest in group D (Er: YAG laser treated Co-Cr), then group B (Laser sintered Co-Cr), then group A (Sandblasted Co-Cr) and group C (Nd: YAG laser treated Co-Cr) which was the least. Conclusion All the groups showed significant difference in shear bond strength. Er: YAG laser surface treated Co- Cr had highest bond strength to porcelain, then laser sintered Co-Cr, followed by sandblasted Co-Cr and least Nd: YAG surface treated Co- Cr. Key Words Er:YAG Laser, Nd:YAG Laser, Conventional technique, Co-Cr alloy, DMLS, Porcelain, Shear bond strength.

To evaluate the effect of different enamel conditioning procedures on the shear bond strength of new metal bracket on previously debonded tooth surface - An in-vitro study

To evaluate the efficacy of different enamel conditioning methods while bonding a new bracket on a previously de-bonded site, and assess the difference in shear bond strength and ARI score if any. 125 human-extracted premolars were selected. 250 premolar brackets were procured. 125 brackets were bonded on the buccal surface of the premolars using different enamel conditioning methods (bonding sequence 1) and was followed by debonding using the Instron Universal testing machine (Debonding procedure I).The remaining 125 brackets were bonded (Bonding sequence II) on the same teeth after the removal of residual adhesive. Bonding sequence II was followed by debonding (Debonding procedure II), shear bond strength calculation, and ARI score calculation. There was a significant difference in SBS between the 5 groups after initial debonding. SEP group (group 4) showed the highest SBS followed by acid etching groups (groups 3, 2, and 1). The sandblasting group (group 5) had the lowest shear bond strength value. After the second debonding, SBS was found to be highest in Group 3 {37% o-phosphoric acid (Bonding I) sandblasting (Bonding II)} followed by Group 4 {SEP (Bonding I and Bonding II)}, group 2 {acid etching (Bonding I) SEP (Bonding II)}, and group 1 (acid etching in both bonding sequences). Group 5 (sandblasting in both sequences) had the least SBS. Non-significant differences were found in ARI score of the five groups. Self-etching primer group had highest SBS and sandblasting group had least SBS after first debond. The SBS of new brackets after two debonding procedures significantly decreased but was still found to be above the required bond strength. SEP and sandblasting can be used as a substitute to acid etching technique in second time bonding of brackets as these groups had higher SBS after second debond.

Evaluation of Shear Bond Strength and Microleakage of Self-adhesive Giomer

This study was aimed to evaluate the bonding performance of a self-adhesive giomer and compare it to a conventional flowable composite resin with regard to shear bond strength and microleakage in enamel and dentin. Healthy human premolars extracted for orthodontic treatments were used in the study. For shear bond strength tests, enamel and dentin specimens were prepared for the study group with selfadhesive giomer and for the control group with conventional flowable composite resin with a 5th-generation adhesive system. A universal testing machine was used to measure the shear bond strength. For the microleakage tests, specimens were immersed in a 2% methylene blue solution for 24 hours, cut into sections, and evaluated with a stereomicroscope for the extent of dye penetration. The results of the study showed no statistically significant difference in shear bond strength between the self-adhesive giomer and the conventional flowable composite resin in enamel (<i>p</i> = 0.091). On the contrary, in dentin, the self-adhesive giomer showed significantly lower shear bond strength (<i>p</i> < 0.0001). The microleakage of the selfadhesive giomer was significantly higher than that of the conventional flowable composite resin (<i>p</i> = 0.002). Self-adhesive giomer is considered useful for restoring small cavities at the enamel level of pediatric patients by reducing chair time with the advantage of a simple bonding process. However, as the study was conducted in a laboratory setting, further research in a clinical environment is deemed necessary.

Effects of the conventional, soft start, and pulse delay modes produced by light-emitting diode device on metal brackets bond strength and enamel damage: An in vitro comparative study

This study aimed to compare the bond strength and enamel damage following debonding of metal brackets cured by different light-curing modes: conventional, soft start, and pulse delay modes. Sixty extracted upper premolars were randomly divided into three groups according to the used light-curing mode. Metal brackets were bonded with a light-emitting diode device employing different modes. Group 1: conventional mode (10s mesial+10 s distal); group 2: soft start mode (15s mesial+15s distal); group 3: pulse delay mode (3s mesial+3s distal, followed by 3min of no photoactivation, then 9s mesial+9s distal). Radiant exposure was the same in all study groups. Shear bond strengths of the brackets were tested with a universal testing machine. A stereomicroscope was used to determine the number and length of enamel microcracks. One-Way ANOVA and Kruskal-Wallis tests were used to detect significant differences in shear bond strength and microcracks number and length among groups. The soft start and pulse delay modes produced significantly greater shear bond strength than the conventional mode (19.46±4.90MPa; 20.47±4.97MPa; 12.14±3.79MPa, respectively, P<0.001). However, there was no significant difference between the soft start and pulse delay groups (P=0.768). The number and length of microcracks increased significantly after debonding in all study groups. The change in microcracks length was not different among study groups. The soft start and pulse delay modes produced greater bond strength than the conventional mode without predisposing enamel to higher risk of damage. Conservative methods for debonding are still required.

Comparison of the shear bond strength in Giomer and resin-modified glass ionomer in class V lesions

IntroductionThere are several cosmetic, restorative materials to restore non-carious Cervical Lesions (NCCLs). The aim of this study was to specify and compare the shear bond strength of Giomer and resin-modified glass ionomer in Class V lesions so that whether Giomer showed a better shear bond strength, it could be used instead of RMGI to restore NCCLs because of its better esthetic. Methodology: 20 maxillary and 20 mandibular intact premolars were collected. Each group of 20 samples was divided into two 10-tooth subgroups of A and B. A class V preparation was made on the buccal surface of the samples with 2*2*3 mm dimensions using a diamond bur. Also, the crossing path of the universal machine chisel was prepped with 2 mm depth up to incisal edge. For group A, after applying BeautiBond and curing it, Beautifil II Giomer was placed in nylon cylinders and the cylinders were placed in the middle cervical region and cured for 20 s. For group B, 1 spoon powder of Fuji II RMGI was mixed with two drops of its liquid and transported to nylon cylinders and placed in the middle cervical region, then cured for 20 s. The nylon cylinders were removed from all 40 samples. Then, all teeth were thermocycled and then tested using a universal machine with the force of 20 MPa and the speed of 1 mm/min until they fractured to assess their shear bond strength. The obtained data was analyzed using SPSS v.26. The significance level was considered 0.05. ResultsThere was no significant difference between Giomer (4.97 ± 2.36) and the resin-modified glass ionomer (3.41 ± 2.71) groups as regards their shear strength (p = 0.059). Likewise, there was no significant difference in shear bond strength between Giomer and RMGI groups as regards jaw type (P = 0.326). ConclusionThe paper suggests that Giomer and resin-modified glass ionomer groups did not differ significantly in terms of their shear bond strength and that both can be utilized to treat Class V lesions. Furthermore, there was no significant difference between the shear bond strength in terms of jaw type.

Comparison of shear bond strength of bonded stainless steel brackets using three different light curing systems: An in vitro study.

To evaluate and compare the shear bond strength of stainless-steel brackets using three different light curing units. Using three LED curing units (3M ESPE Elipar, Ivoclar bluephase, and Woodpecker I LED light cure), 120 precoated metal brackets (Gemini series, 3M Unitek) were cured. The shear bond strength was recorded using a universal testing machine. The shear strength of the bracket in different light-curing systems was examined with ANOVA test. The mean shear strength of group A, group B, and group C were 16.03 ± 14.30 MPA, 16.86 ± 11.89 MPA, and 20.51 ± 19.40, respectively. The result of the analysis shows that there is a major difference in shear bond strength of these three different light-curing systems with F value = 3.94 and P value 0.04. We used three LED light-curing units with different intensities and manufacturing companies. The result showed that woodpecker I LED light had significantly highest mean SBS than the other two (Elipar LED curing light and 3M ESPE, Ivoclar bluephase).

Effect of Different Surface Treatments and Application Times on Shear Bond Strength Between Polyetheretherketone and Composite Resin

Objective: To investigate the effect of various surface treatments and different application times on shear bond strength between polyetheretherketone and composite resin. Methods: A total of 110 disc-shaped polyetheretherketone specimens were randomly divided into 9 groups and 4 different surface treatments (control, sandblasting, tribochemical silica coating, sulfuric acid) were applied. The sandblasting, tribochemical silica coating, and sulfuric acid processes were performed 3 different times (10s, 15s, 20s). Then, the composite resins were applied to the treated surfaces of the polyetheretherketone specimens. The shear bond strength test and scanning electron microscopy analysis were performed. The data were statistically analyzed using analysis of variance and Duncan honest significant difference test. Results: One-way analysis of variance revealed differences in shear bond strength among the groups (p &lt;0.001). While the control group showed the lowest bond strength values (4.24 ± 1.53 MPa), 20 s of sulfuric acid process showed the highest bond strength values (27.91 ± 4.44 MPa). Conclusion: Depending on the application time to the material, additional surface treatments increase the polyetheretherketone composite bonding. Surface treatments with sulfuric acid applications provide higher surface bonding values than other treatments

Shear bond strength fissure sealant based on glass ionomer after topical fluor application: a comparison between sodium fluoride and acidulated phosphate fluoride

Background: Application of fissure sealants to young permanent teeth is one of the preventive measures for caries in the field of dentistry. Fissure sealants based on glass ionomer cement (GIC) have the advantage of releasing fluoride. Sodium fluoride and acidulated phosphate fluoride (APF) are remineralization agents because they can increase remineralization by altering hydroxyapatite to fluorapatite and this in turn makes fluorine able to increase pH. Fluoride can prevent caries by increasing remineralization of the enamel that has just been demineralized by acids produced by plaque bacteria. The aim of this study is to compare the shear bond strength fissure sealant based on glass ionomer between sodium fluoride and APF topical fluor application Method: This research applied true experimental design with post test only control group design. The 21 maxillary permanent premolars were distributed into 3 groups, namely the control group (K1), the treatment group added 5% sodium fluoride (K2), and the treatment group added 1.23% APF (K3). Result: One Way ANOVA and post hoc LSD analysis test displayed no significant difference in each group. This could be due to the material used as a conditioner prior to the GIC application. The addition of fluoride ions will inhibit the demineralization process of the enamel produced by the application of conditioner. So it does not rule out that it will interfere with the attachment of the GIC material used as a fissure sealant in this research. Conclusion: There was no significant difference in shear bond strength of fissure sealant based on glass ionomer between sodium fluoride and acidulated phosphate fluoride topical application.

Comparative evaluation of shear bond strength of calcium silicate-based liners to resin-modified glass ionomer cement in resin composite restorations - a systematic review and meta-analysis.

Purpose The aim of this systematic review was to evaluate the difference in shear bond strength between calcium silicate-based liners to resin-modified glass ionomer cement (RMGIC) in resin composite restorations.Materials and methods The protocol was registered in PROSPERO following which primary research was carried out on Medline, Scopus and Cochrane library. To assess the risk of bias, a customised tool was used. Among the 194 records retrieved from the databases, only ten articles qualified for qualitative and quantitative synthesis after meeting all the requirements of the eligibility criteria. Covidence software was used to record the decisions. Studies published until 31 March 2021 were taken up for the review. The articles showed a low-to-moderate risk of bias. I2 test was used to check the percentage variation due to heterogeneity.Results RMGIC showed a higher shear bond strength value compared to the three calcium silicate liners MTA, Biodentine and TheraCal LC. However, TheraCal LC and MTA showed better bond strength than Biodentine. Cohesive failure was seen predominantly in liners followed by adhesive failure. RMGIC shows mixed mode of failure in some studies.Conclusions RMGIC is preferred over calcium silicate-based materials as the liner to be used under resin composite restorations. Among calcium silicate-based materials, TheraCal LC showed a better bond strength value. The mode of failure was predominantly cohesive in all the liner groups in majority.

Comparative Evaluation of Shear Bond Strength of Nanohybrid Composite Restoration After the Placement of Flowable Compomer and Composite Using the Snowplow Technique.

Aim: Based on the importance of bonding during restoration, this in vitro study aimed to evaluate the difference in shear bond strength of nanohybrid composite restoration in molars after the placement of flowable compomer and composite using the snowplow technique.Materials and methods: Twenty-four freshly extracted molars were taken and sectioned at the level of 2.5 mm from the coronal cusp and root tip. These sections were embedded in methacrylate and, after etching and bonding, were randomly divided into two groups (n=12) for placement of restorative materials. In group A, the plastic tube was filled with uncured flowable composite resin followed by the placement of packable nanohybrid composite in oblique increments. In group B, the plastic tube was filled with uncured flowable compomer followed by the placement of packable nanohybrid composite in oblique increments. Each specimen was then tested under a universal testing machine to determine the shear bond strength.Results: Independent sample 't' test revealed a statistically significant difference between the mean shear bond strength of compomer and composite (P value<0.001), where flowable composite showed higher values compared to compomer. Conclusion: It was seen that the use of composite showed a significantly better bond strength of the restoration when compared to compomer using the snowplow technique. Both materials and application techniques can influence the bond strength of a material as determined in this study.

Immediate bond performance of resin composite luting systems to saliva-contaminated enamel and dentin in different curing modes.

The purpose of this study was to evaluate the immediate shear bond strength of resin composite luting systems to tooth with or without saliva contamination in different curing modes. The Knoop hardness number of the resin composite luting agents was measured. Four combinations of resin composite luting systems were used. The shear bond strength to bovine teeth was measured with and without saliva contamination in different curing modes at different storage periods. The Knoop hardness number of the resin composite luting agents was also evaluated. Significantly lower enamel and dentin shear bond strengths and Knoop hardness number values were observed in all resin composite luting systems at 5min versus 24 h, regardless of the curing mode or saliva contamination. The influence of the curing mode of the resin composite luting systems on shear bond strengths and Knoop hardness number was dependent on material. For the saliva contamination conditions, only G-CEM ONE EM did not show any significant difference in shear bond strength among the groups with and without saliva contamination, regardless of curing mode, storage period, or tooth substrate. All the resin composite luting systems showed lower shear bond strengths and Knoop hardness number values immediately after setting.

Comparative Evaluation of Effect of herbal antioxidants on the shear bond strength of composite resin to enamel following vital teeth bleaching: An In Vitro Study

Aim: This study aimed to determine the effect of 2% Olive leaf extract and 2% green tea extract on the shear bond strength of composite resin to enamel following vital teeth bleaching using 40% hydrogen peroxide. Methodology: The study used thirty extracted human upper central incisors. Samples were randomly categorized into 3 groups (n=10). Group I- Control- composite was build-up right after bleaching, Group II - Bleaching with 40% H2 O2 and 2% Olive leaf extract treatment followed by composite build-up, Group IIIBleaching with 40% H2 O2 and 2% green tea extract treatment followed by composite build-up. The specimens’ shear bond strength was assessed using Universal Testing Machine. One-way ANOVA test followed by Tukey’s Post-hoc test was used to assess the mean shear bond strength among the study groups. Results: Mean shear bond strength of the 2% Olive leaf extract group was 201.70, 2% Green tea extract was 123.40, and the control group was 42.20. This mean difference in shear bond strength among the groups was statistically significant at P=0.003. Conclusion: Within the constraints of the research, it can be inferred that 2% Olive leaf extract and green tea extract can be used to reverse the effect of bleaching on the bond strength of composite resin to the enamel.

Investigation of the effect of simultaneous use of silver diamine fluoride and potassium iodide on the shear bond strength of total etch and universal adhesive systems to dentin.

Background:Applying silver diamine fluoride (SDF) is recommended to arrest and prevent dental caries. However, it may jeopardize the bond of the restorative materials to the tooth. The aim of the present in vitro study was to evaluate the effect of the simultaneous use of the SDF and potassium iodide (KI) on shear bond strength to the sound dentin.Materials and Methods:In this in vitro study, on the buccal and lingual surfaces of the 48 human third molar teeth, dentinal surfaces with a diameter of 6 mm were created by removing the enamel. Then, the specimens were divided into four groups based on applying or not applying the KI/SDF and adhesive type (etch and rinse [E and R] or universal adhesive). Afterward, cylindrical composite restoration was made on the surfaces. Half of the specimens were subjected to 1000 cycles of thermocycling. Subsequently, the shear bond strength was evaluated by Universal testing machine. Furthermore, the type of failure was determined by a stereomicroscope. Data were analyzed by t-test and Chi-square at a significance level of P < 0.05.Results:There were statistically significant differences in shear bond strength between Groups 1 and 3 (P < 0.05), whereas the bond strength difference between Groups 2 and 4 was not statistically significant (P = 0.609). Failures were predominantly of the mixed type in almost all groups.Conclusion:Based on the results of this study, the superiority of shear bond strength of universal adhesive to the sound dentin compared to E and R adhesive was confirmed. Thus, using this type of adhesive is recommended under the condition that KI/SDF anticaries material is applied.

Shear bond strength after using sealant before bonding: a systematic review and meta-analysis of in vitro studies.

Decalcification during orthodontic treatment is significantly increased. To prevent this negative impact, new treatments with sealants before bonding brackets are commonly been used. This systematic review discusses current knowledge on shear bond strength when using sealant before bonding. A systematic review and meta-analysis were performed to identify studies that address shear bond strength after using a sealant before bonding brackets. The search was carried out using common electronic databases in addition to individual searches. Both screening and study eligibility analysis were performed according to PRISMA and Cochrane Guidelines for systematic reviews. Several terms describing shear bond strength after using a sealant before bonding brackets were searched. Particular attention was paid to bond failure and bracket loss. For the statistical outcome, all results were shown in a forest plot based on standardized mean differences (SMD) with a random-effects model to respect heterogeneity of these studies. To assess the heterogeneity of the different trials, I2-value and the Q-Test were performed. The initial search identified 416 studies. After a thorough selection process, a total of 15 articles met the inclusion criteria. All 15 articles reported results of in vitro studies. Papers were divided into four subgroups according to their used product: ProSeal, Transbond bonding, the combination of Transbond bonding and ProSeal and Clearfil Protect Bond. The results of this review demonstrate a high heterogeneity of the studies. The SMD of the examined 15 articles show nearly no difference between the control and the intervention groups in shear bond strength (p < 0.0001; OR - 0.12; Cl - 0.47-0.23). Forest plots for comparison of the subgroups depict no difference in shear bond strength as well. This meta-analysis concludes that there is no additive benefit for shear bond strength when using sealant before bonding. However, additional randomized controlled studies should be performed to analyze impact of sealants on bonding strength and bracket loss in more detail. Using sealants before orthodontic bonding does not reduce shear bond strength.

Bond Strength and Microleakage of a Novel Glass Ionomer Cement Containing Silver Diamine Fluoride.

Objectives To investigate the shear bond strength and microleakage of glass ionomer cement (GIC) containing silver diamine fluoride (SDF). Materials and Methods Sound human permanent premolars were divided into the following three groups: 1) GIC (Fuji IX), 2) GICSDF-S: GIC + SDF (Saforide), and 3) GICSDF-T: GIC + SDF (Topamine). Shear bond strength ( n = 14/group) was measured using a universal testing machine and compared between groups (one-way ANOVA and Tukey HSD, p < 0.05). Microleakage ( n = 15/group) at enamel and dentin margins was scored using a stereomicroscope (10x) and compared between groups (Chi-square, p < 0.05). Results There were significant differences in shear bond strength between the GIC and GICSDF-S groups and between the GIC and GICSDF-T groups. The GIC group had the lowest shear bond strength among the groups; however, there was no significant difference between the GICSDF-S and GICSDF-T groups. The microleakage test results were not significantly different between groups at the enamel margin or dentin margins. Although the GIC group demonstrated a higher dye penetration score at the enamel and dentin margins, the difference was not significant. Conclusions Within the limitations of this study, we conclude that incorporating SDF into GIC results in higher shear bond strength while not increasing microleakage at the enamel and dentin margins.

An In Vitro Evaluation of the Mechanical Properties and Fluoride-releasing Ability of a New Self-cure Filling Material

The aim of this study was to examine and compare the flexural strength, shear bond strength, and fluoride-releasing ability of glass ionomer cement (GIC), Fuji IX GIC®, and a new alkasite filling material, Cention N®. The materials were divided into two groups, Fuji IX GIC® (n = 30) and Cention N® (n = 30) and further divided (n = 10) to test three parameters, the fluoride releasing ability, flexural strength, and shear bond strength. Fluoride release was checked using fluoride ion-selective electrode, and flexural strength and shear bond strength were tested using universal testing machine (Intron 3366, UK). Fluoride release of Fuji IX GIC® was significantly higher compared to that of control Cention N® over a period of 21 days. Flexural strength of Cention N® was significantly higher compared to Fuji IX GIC® and there were no significant differences in shear bond strength of both the materials. From the results of the study, it can be concluded that Cention N® is an alkasite filling material for the complete and permanent replacement of tooth structure in posterior teeth and can be a good alternative when compared to GICs on the basis of their superior mechanical properties. Cention N® is an innovative filling material for the complete and permanent replacement of tooth structure in posterior teeth and can be a good alternative when compared to GICs on the basis of their superior mechanical properties.

Effect of Ti: Sapphire and Nd: YAG Lasers on Shear Bond Strength at the Zirconia - Veneering Ceramic Juncture.

Introduction: This study was conducted to assess the impact of nanosecond and femtosecond lasers on shear bond strength at the zirconia - veneering ceramic juncture. Materials and Methods: The first 60 samples of partially sintered zirconia cylindrical discs measuring 7 mm diameter and 4 mm height were milled and sintered. Then they were randomly divided into three groups namely group C (control, n=10), group N (Nd: YAG laser, n=10), and group T (Ti: sapphire laser n=40) which was further divided based on the duration of laser irradiation, into 4 subgroups (n=10 each) which were 30 seconds, 1 minute, 2 minutes and 3 minutes. Surface treatment was done on sintered zirconia discs based on the group. Following the treatment, the discs were ultrasonically cleaned followed by liner application (IPS Emax Zirliner, Ivoclar-Vivadent) and veneer ceramic layering (IPS e.max Ceram, Ivoclar-Vivadent) of 1.5 mm height. Each sample underwent shear stress in the universal test machine on the mounting jig, and bond strength was evaluated. Data were assessed using ANOVA followed by Tukey's post hoc multiple comparison analyses. Results: According to one-way ANOVA, there was a significant difference in shear bond strength between the groups. Tukey's post hoc pair wise comparison test showed a significant difference (P value = 0.001) in shear bond strength of all pairs except group C and group N. The results of repeated measures, ANOVA (related and dependent groups) and Tukey's multiple pair wise comparison test showed that there was a significant difference (P value = 0.001) in shear bond strength at 30 seconds and all other groups. Conclusion: Ti: sapphire laser irradiation for 30 seconds can be used as potential surface treatment to increase shear bond strength at the zirconia-veneering ceramic juncture.

Bond strength of orthodontic buttons on clear aligner materials

ABSTRACT Purpose To evaluate the shear bond strength of orthodontic buttons bonded on various clear aligner materials using orthodontic plastic adhesive. Materials and methods Three types of thermoplastic materials: 1) Duran (Polyethylene terephthalate glycol), 2) Essix A+ (Polyethylene terephthalate glycol), and 3) Zendura (Polyurethane) were bonded with either metal or plastic buttons using orthodontic plastic adhesive (Bond aligner®). Six experimental groups with 15 specimens per group were prepared. Bond strength testing was done according to the Lap Shear Test Method (ASTM D3163) using the universal testing machine. Bond failure mode (modified from ASTM D5573) was examined with a stereoscope. Kruskal-Wallis and post hoc tests were used to analyse the differences in shear bond strength among the six groups. Results Mean bond strengths were as follows: 1) Duran-metal (DM) (7.04 MPa); 2) Duran-plastic (DP) (5.37 MPa); 3) Essix-metal (EM) (5.55 MPa); 4) Essix-plastic (EP) (4.62 MPa); 5) Zendura-metal (ZM) (1.17 MPa); and 6) Zendura-plastic (ZP) (1.40 MPa). Shear bond strength among the three thermoplastic materials were significantly different (p < .05). For the bond failure mode, regardless of button type, Duran and Essix A+ showed substrate failure of the thermoplastic sheet, while Zendura showed adhesive failure at the thermoplastic sheet interface. Conclusion Orthodontic buttons bonded on Duran and Essix A+ using orthodontic plastic adhesive could achieve very high bond strength that the thermoplastic sheets would tear before button detachment occurred. Buttons bonded to Zendura resulted in significantly greater bond failure rates.

The Effect of Curing Pressure on Shear Bond Strength of Zirconia to Resin Cement

Background: Nowadays, the esthetics demand is continuously increasing; therefore, metal-free materials are widely used, like a zirconia-based ceramic, which is conveniently fabricated via computer-aided design and computer-aided manufacturing (CAD/CAM) system for restorations from single to full mouth rehabilitation. Objective: This study evaluated the effect of pre-curing pressure on the shear bond strength of zirconia to the resin cement. Methods: A total of sixty-three sandblasted cylindrical zirconia mounted in autopolymerizing resin were randomly assigned to three groups; Group 1: no treatment (control), Group 2: negative pressure, and Group 3: positive pressure to resin cement after resin cement application and resin composite columns bonded to zirconia. Thirty-three of the samples were stored in distilled water at 37 °C for 24 hr before the shear bond strength test for thirty samples and three samples were cross-sectionally cut for interfacial observation with FESEM. Another thirty samples were thermocycled for 5,000 cycles in distilled water at 5°C to 55 °C before testing. The shear bond strength and failure mode were evaluated. Examination of the bonding interface was also done. Results: The results were analyzed using two-way ANOVA. The means of shear bond strength of non-thermocycle of the control group were 8.01 ±1.74 MPa, 9.10 ±1.90 MPa, and 9.14 ±2.58 MPa, whereas that of thermocycle group were 5.71 ±0.84 MPa, 5.53 ±0.68 MPa, and 5.68 ±0.77 MPa in zero pressure group, negative pressure group, and positive pressure group, respectively. It showed no statistically significant differences in shear bond strength in all pressure groups (p &gt; 0.05). The pre-curing pressure did not influence the shear bond strength of the zirconia and resin cement. Conclusion: There was no difference in the shear bond strength between the pressure groups and the no treatment control group. The positive and negative pressure did not influence the shear bond strength of the zirconia and resin cement.

Effect of Contamination with Hemostatic Agent on Shear Bond Strength of Composite to Dentin Using G-Premio and Single Bond Universal Adhesives.

Objectives: Bond strength of composite restorations plays an important role in their success. This in vitro study evaluated the effect of a hemostatic agent on shear bond strength of universal adhesives. Materials and Methods: Thirty-six extracted human molars were used in this study. Buccal and lingual surfaces were reduced to obtain flat dentin surfaces and were ground with a silicone paper. The samples were randomly divided into three groups (n=12) based on the application of hemostatic agent: group 1: no contamination (control), group 2: aluminum chloride application, and group 3: ferric sulfate application. Each group was then divided into two subgroups (n=6) for using G-Premio and Single Bond Universal. Resin cylinders (Filtek Z550) were bonded to dentin surfaces according to the manufacturer’s instructions. After 1000 thermal cycles, shear load was applied to the specimens using a universal testing machine at a crosshead speed of 1 mm/min until failure. Data were statistically analyzed using two-way ANOVA and Tukey’s post-hoc test (α=0.05). Results: There were statistically significant differences in shear bond strength of the three main groups for both G-Premio and Single Bond Universal (P<0.05). When the adhesive systems were compared with each other, G-Premio showed higher shear bond strength than Single Bond Universal (P<0.05). Conclusion: Contamination with hemostatic agents had an adverse effect on the shear bond strength of universal adhesives. Moreover, G-Premio yielded a higher bond strength than Single Bond Universal.