Mean Shear Bond Strength Research Articles

The impact of temperature on the shear bond strength of conventional multi-step and self-adhesive orthodontic adhesive systems: an in-vitro study

BackgroundA recurring issue during orthodontic treatment is the detachment of brackets from the tooth surface, which proves problematic for both the patient and the orthodontist. This study aimed to evaluate the impact of various temperatures on the shear bond strength of metal molar tubes, using conventional multi-step and self-adhesive orthodontic adhesive systems.MethodsA total of 112 extracted human molars were randomly divided into eight groups (n = 14) for bonding tubes with two orthodontic adhesive systems (Transbond XT and GC Ortho Connect) at different temperatures: refrigeration temperature (4 °C), room temperature (20 °C), human body temperature (37 °C), and high temperature (55 °C). The shear bond strength (SBS) test was conducted using a universal testing machine set to a crosshead speed of 0.5 mm/min. The adhesive remnant index (ARI) was used to evaluate the amount of adhesive remnants on the molar surfaces. ARI scores were assessed under Carl Zeiss Stemi 2000-CS stereomicroscope with image recording camera AxioCam Mrc5 at ×10 magnification. The data were analyzed using Student’s t-test, parametric analysis of variance (ANOVA), the intra-class correlation coefficient (ICC), the Kruskal-Wallis test, and the chi-square test.ResultsHigher mean SBS values were obtained with Transbond XT compared to GC Ortho Connect resin; however, the difference was not statistically significant (p > 0.05). The SBS results were lowest at 20 °C and highest at 55 °C in the Transbond XT group, and lowest at 37 °C and highest at 20 °C in the GC Ortho Connect group with no statistically significant difference (p > 0.05). The distribution of the ARI scores between the two materials showed a statistically significant difference (p = 0.002), with higher ARI scores found in the Transbond XT group.ConclusionsPre-heating orthodontic adhesives prior to bonding does not affect the shear bond strength.

Effect of Multiple Firing Cycles on Shear Bond Strength Between Zirconia and Lithium Disilicate.

BACKGROUND Indirect ceramic restorations often need multiple firings to match the shade of natural teeth or need after-correction and ceramic addition during the clinical trial stage. Many studies have examined how multiple firings affect the mechanical characteristics of zirconia-veneered prostheses. The effect of firing number on adhesion between these core and heat-pressed lithium disilicate veneering ceramics is unclear. This study aimed to evaluate and compare the effects of repeat firings on the planar interface shear bond strength (SBS) using the Schmitz-Schulmeyer test between zirconia core and veneering heat-pressed lithium disilicate. MATERIAL AND METHODS Forty standard-sized rectangular zirconia framework specimens were fabricated using the Schmitz-Schulmeyer test, a test to assess bonding quality, and categorized into 4 groups: control, 1 firing cycle, 2 firing cycles, and 3 firing cycles. The additional firing cycles aimed to simulate clinical scenarios. SBS was tested using a universal testing machine. RESULTS The study found that mean SBS values were similar across experimental groups, with the control group showing slightly higher values. Analysis using ANCOVA revealed no significant difference in mean SBS between groups, but maximum load significantly influenced SBS. Regression analysis and Pearson correlation confirmed the significant relationship between maximum load and SBS (P<0.0001). CONCLUSIONS There was no apparent effect on the SBS from increasing the firing from 1 to 3 cycles, indicating that the study's hypothesis was not supported. The mode of failure, which was largely adhesive, did not tend to vary as the number of firing cycles rose, despite the fact that some samples in all groups showed mixed failure.

Bond strength of self-adhesive resin cement to definitive resin crown materials manufactured by additive and subtractive methods

The aim was to compare different surface pretreatments on definitive resin crown materials manufactured additively or subtractively in terms of shear bond strength (SBS) values. Seven subgroups (n=10) were formed from additively manufactured VarseoSmile Crown Plus (VS) and subtractively manufactured Cerasmart270 blocks (CS) according to different surface pretreatments applied; sandblasting (subgroup SB), hydrofluoric acid (subgroup HF), Multi Primer (subgroup MP), subgroup SB-HF, subgroup SB-MP, subgroup SB-HF-MP, and control subgroup. A 3-mm-diameter composite was cemented onto each sample by self-adhesive resin cement. SBS values were measured and failure modes were analyzed after thermocycling. Data were analyzed with two-way ANOVA and Tukey HSD tests. The mean SBS value of VS was found significantly higher than CS (p<0.001). Subgroups SB-HF-MP, HF, SB-MP, and MP of VS exhibited the highest SBS values (p<0.001). The VS exhibited mostly cohesive failure, while CS exhibited mostly adhesive failure.

Primary Dentin Conditioning with Methylene Blue Activated Photodynamic Therapy, Phytic Acid, and Er,Cr:YSGG to Resin-Modified Glass Ionomer Cement in Comparison to Conventional Polyacrylic Acid.

Aim: Impact of surface conditioner phytic acid (IP6) Er,Cr:YSGG laser (ECYL) methylene blue photodynamic therapy (MB-PDT) on the microleakage and shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) to primary sound dentin. Material and method: Overall, 80 extracted sound primary molars were collected followed by their submergence in self-cure acrylic resin. The dentin surface was exposed and made flat and was assigned into four groups based on the surface conditioning. Group 1: polyacrylic acid (PAA), Group 2: 1% IP6, Group 3: ECYL, and Group 4: MB-PDT. RMGIC restorative material was bonded to primary dentin. Marginal leakage assessment was performed using silver nitrate. SBS and failure mode assessment were performed using a universal testing machine and stereomicroscope. Mean and standard deviations of SBS and marginal leakage were compared using analysis of variance and multiple comparisons of Tukey's post-hoc test (p < 0.05). Results: MB-PDT treated specimens displayed the highest values of marginal leakage (37.56 ± 1.25 nm) and lowest SBS (7.93 ± 1.03 MPa). However, samples in Group 2 conditioned with IP6 presented the lowest dye penetration score (11.23 ± 1.22 nm) and highest bond strength scores (11.12 ± 0.82 MPa). Conclusions: IP6 and ECYL have proved to be better alternatives in terms of low microleakage and improved SBS scores to PAA as a primary dentin surface conditioner for bonding RMGIC restoration. Conversely, MB-PDT, when employed as a dentin surface conditioner for RMGIC restorations, exhibited suboptimal results, characterized by elevated microleakage and compromised bond strength.

Comparison of Shear Bond Strength for Onestep Self-etch versus Universal Adhesives on Contaminated and Decontaminated Dentin Surfaces: An In-vitro Study

Introduction: Ensuring strong adhesion of composite resin to dentin requires isolation, as moisture contamination from gingival fluid, blood, or saliva can weaken the bond. This can lead to microleakage, restoration loss, recurrent caries, postoperative sensitivity and discolouration. Long-lasting restorations are crucial in adhesive dentistry, but contamination often results in adhesion failure. To restore bond strength, various decontamination procedures are recommended. Aim: To evaluate and compare the effects of different contaminants and ethanol decontamination on the shear bond strength of onestep self-etch versus universal adhesives to dentin. Materials and Methods: This in-vitro study, conducted in the Department of Conservative Dentistry and Endodontics at Sibar Institute of Dental Sciences in Guntur, Andhra Pradesh, India, from July 2023 to October 2023, utilised the buccal surfaces of 70 human molars. The molars were divided into two groups (n=35): Group 1 - One-step self-etch adhesive and Group 2 - Universal adhesive. Each group was further subdivided into five sub-groups (n=7): Control (Subgroup A), Saliva contamination (Subgroup B) Blood contamination (Subgroup C) Saliva contamination followed by ethanol decontamination (Subgroup D) and Blood contamination followed by ethanol decontamination (Subgroup E) followed by ethanol decontamination. A plastic tube loaded with composite resin was placed over the dentin surface and light-cured. Shear bond strength at the dentincomposite interface was evaluated using a Universal Testing Machine (UTM). One-way Analysis of Variance (ANOVA) for intergroup comparison followed by Tukey’s post-hoc test for multiple comparisons was performed. Differences were considered significant at p-value ≤0.05 between groups. Results: The average shear bond strength (MPa) for subgroups in both adhesive groups showed a statistically significant difference (p-value ≤0.05). Subgroup A had the highest bond strength (25.786 MPa and 46.943 MPa) and subgroup C had the lowest (8.986 MPa and 9.871 MPa). In both groups, the mean shear bond strength followed this order: Subgroup A &gt; D &gt; E &gt; B &gt; C. Comparison between Group 1 and Group 2 using an independent t-test showed no statistically significant difference in any subgroup (p-value &gt;0.05). Conclusion: The present in-vitro study found that blood and saliva contamination reduced shear bond strength to dentin, with blood having a greater impact. Decontamination with ethanol improved bond strength in both adhesive groups.

Evaluation of the Effect of Applying Chitosan, Neem, Tulsi, Aloe vera, and Chlorhexidine Solutions on the Shear Bond Strength of Composite to Dentin.

Dentin adhesion is challenging and needs modifications. Newly introduced nature-derived materials may be a useful solution in improving dentin adhesion. The use of natural antimicrobial agents for pretreating prepared dentin surfaces before restoration has become of interest. The present study investigated the effect of natural compounds on the shear bond strength (SBS) of resin composite adhesively bonded to dentin. Sixty extracted human molar teeth were randomly divided into six groups (n= 10); Group I: two-step etch and rinse adhesive system, Adper Single Bond 2 (SB2) (experimental control), Group II: 2.5% Chitosan+etch+SB2, Group III: 15% Neem (Azadirachta indica)+etch+SB2, Group IV: 15% Tulsi (Ocimum sanctum)+etch+SB2, Group V: 2% Aloe vera+etch+SB2, and group VI: 2% Chlorhexidine (CHX)+etch+SB2. Resin composite (Z350, 3M ESPE USA) was placed over the prepared dentin surfaces and was light cured. Data analysis was performed using One-way ANOVA and post hoc Tukey's test (p< 0.05). Neem specimens showed the highest mean SBS, statistically greater than the control (p= 0.042). Other experimental groups showed no significant differences in SBS comparison to the control. The mean SBS values of 2.5% Chitosan, 15% Neem, 15% Tulsi, and 2% Aloe vera were significantly higher than 2% CHX (p= 0.046, p= 0.001, p= 0.010 and p= 0.002 respectively). Dentin pretreatment with Neem may improve the bond strength of a two-step etch and rinse adhesive system. The application of Chitosan, Tulsi, Aloe vera, and CHX did not demonstrate significantly different SBS values from that of the Control, although CHX was lower.

Comparison of Fracture Resistance Force (Load-to-fractured Test) and Failure Type of 3D-printed Stainless Steel Crowns and Preformed Stainless Steel Crowns in Primary Molars: An In Vitro Study.

This study aims to compare the fracture resistance force (FRF) and failure types of three-dimensional (3D)-printed stainless steel crowns (SSCs) and preformed SSCs in primary molars. Forty-eight over-retained and extracted mandibular second deciduous molars were divided into two groups: one receiving 3D-printed crowns and the other preformed crowns. Fracture resistance testing was performed using a universal mechanical testing machine, and failure types were analyzed post-testing. Fracture resistance testing revealed a significant difference between 3D-printed and preformed SSCs (p < 0.05), with 3D-printed crowns exhibiting a mean FRF of 3953.82 N compared to 742.94 N for preformed crowns. Additionally, Mann-Whitney U tests and Chi-squared tests were utilized to examine variations within and across the groups. Analysis of shear bond strength showed that 3D-printed crowns demonstrated superior adhesive performance compared to preformed crowns, with mean shear bond strength values of 3953.82 N and 742.94 N, respectively. Both groups A and B showed unrepairable failure modes. The study concludes that 3D-printed SSCs offer distinct advantages over preformed options, including tailored fit, enhanced mechanical properties, and improved longevity. These findings underscore the potential of 3D printing technology to revolutionize pediatric dental restoration practices. Integrating 3D printing into pediatric dental practice holds promise for optimizing treatment outcomes and improving long-term oral health in children. The superior fracture resistance and adhesive performance of 3D-printed crowns suggest their potential to enhance restoration viability and reduce the need for subsequent interventions. Giridharan DL, Gopal S. Comparison of Fracture Resistance Force (Load-to-fractured Test) and Failure Type of 3D-printed Stainless Steel Crowns and Preformed Stainless Steel Crowns in Primary Molars: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(10):1129-1134.

Evaluation of Clear Aligner Attachments Bonded to Lithium Disilicate Ceramic Prepared with Different Surface Roughening Methods: An In Vitro Study.

This study aims to assess the effects of surface conditioning and different composite types on the surface roughness (SR) and shear bond strength (SBS) between lithium disilicate and clear aligner composite attachments. Eighty ivoclar vivadent pressable (IPS) e.max press specimens were randomly allocated into four groups (n = 20) based on the surface treatment method employed. Group I: Used sandblasting with 50 μm Al2O3 slurry particles; group II: Used 9.5% hydrofluoric acid (HFA); group III: Used 37% phosphoric acid (PhA); and group IV: Used an Er,Cr:YSGG laser. Surface roughness was measured using a stylus profilometer. For SBS, each group was split into two subgroups based on the composite type (n = 10): FiltekTM Z350 supreme ultra flowable and FiltekTM Z350. The evaluation of SBS was conducted using Instron universal testing equipment. The results indicated that the sandblasting group gave the highest mean surface roughness, while the 37% PhA group showed the lowest recorded value. In addition, the HFA group had the highest mean SBS, while the 37% PhA group demonstrated the lowest SBS. The interaction of HFA and FiltekTM Z350 demonstrated the highest SBS, followed by sandblasting and FiltekTM Z350. The current study may guide orthodontists to choose the appropriate composite material and conditioning technique to achieve a strong SBS between clear aligner composite attachments and lithium disilicate ceramic. How to cite this article: Fayyadh AM, Elbialy MA, Tawfik MA. Evaluation of Clear Aligner Attachments Bonded to Lithium Disilicate Ceramic Prepared with Different Surface Roughening Methods: An In Vitro Study. J Contemp Dent Pract 2024;25(8):766-771.

Assessing the Different Nanoparticle-Reinforced Bonding Agents on the Shear Bond Strength of Orthodontic Brackets

ABSTRACT Background: The strength of the binding between brackets and tooth surfaces has a major impact on how well orthodontic therapy works. The shear bond strength of orthodontic brackets may be strengthened by the invention of bonding agents supplemented with nanoparticles, thanks to recent developments in nanoparticle technology. Materials and Methods: In order to perform a randomized controlled experiment, 90 human premolars were excised for orthodontic purposes. Three groups of 30 teeth were randomly assigned to each group: Group A used a bonding agent augmented with nanoparticles of titanium dioxide (TiO2), Group B used nanoparticles of zirconium dioxide (ZrO2), and Group C used a standard bonding agent as a reference. The appropriate bonding chemicals were used to attach the brackets to the teeth, and a universal testing equipment was used to measure the shear bond strength. Stereomicroscopic analysis was used to evaluate the failure mechanisms. To do statistical analysis, Tukey’s post hoc test and analysis of variance were used. Results: There were significant differences (P &lt; 0.05) in the mean shear bond strength values across the groups. The average shear bond strength for Group A (TiO2) was 18.5 ± 2.3 MPa, that for Group B (ZrO2) was 17.2 ± 2.6 MPa, and that for Group C (control) was 14.8 ± 2.4 MPa. In comparison to Groups B and C, Group A exhibited a statistically greater bond strength, although Group B also showed an improvement over the control. According to the failure mode analysis, the control group had mostly adhesive failures, whereas the nanoparticle groups saw mixed failures. Conclusion: When TiO2 and ZrO2 nanoparticles are added to bonding agents, the shear bond strength of orthodontic brackets is greatly increased in comparison to traditional bonding agents. TiO2-reinforced materials performed better, pointing to possible benefits for orthodontic applications. It is advised that further study be done to examine the long-term impacts and therapeutic implications of these results.

Comparative evaluation of desensitizing agents on shear bond strength of zirconia to dentin

BackgroundThe purpose of the study is to evaluate the effect of 7 different desensitizing agents on the shear bond strength (SBS) of zirconia restorations to dentin with a self-adhesive resin cement and determine the failure modes.MethodsEighty molars’ occlusal surfaces were ground to expose dentin and were randomly divided into 8 groups (n = 10): 1. Gluma (HEMA/Glutaraldehyde) 2. Bifluoride (Sodium Fluoride/Calcium Fluoride) 3. Admira (Bis-GMA/HEMA) 4. Smart Protect (Glutaraldehyde) 5. Teethmate (Tetracalcium phosphate, Dicalcium phosphate) 6. Clinpro White (Sodium fluoride) 7. BisBlock (Oxalic acid) and 8. Control (No-treatment). After applying the agent, a self-adhesive resin cement (Rely-X U200) was used to lute zirconia discs (4 mm height and 4 mm diameter) to dentin. After stored in distilled water at 37 °C for 24 h, all groups were thermocycled for 2500 cycles between 5 ± 2 °C and 55 ± 2 °C. Specimens were submitted to SBS test with a universal testing machine at a crosshead speed of 0.5 mm/min until failure. SBS values were compared with ANOVA. Post-hoc multiple comparisons were performed with Dunnett T3. The failure modes of specimens were examined with stereomicroscope at a magnification of 20X and the distribution of the failure modes were evaluated with Pearson Chi-Square test.ResultsRegarding mean SBS values in MPa’s; Admira (10.70 ± 3.99), Smart Protect (9.62 ± 3.93), and Gluma (8.90 ± 3.76) treatments showed higher SBS values compared to control group (p < .05) according to ANOVA. The SBS values of Teethmate (5.31 ± 2.37) and Clinpro White (4.32 ± 2.44) were higher than control group but the difference was not found significant (p > .05). BisBlock (2.33 ± 1.94) and Bifluouride (1.60 ± 1.47) groups showed the lowest SBS values but their difference between control group was not found statistically significant (p > .05). Most specimens showed adhesive failure but no statistically significant difference was found in the distributions of failure modes according to Chi-square test.ConclusionWithin the limitation of the study; Admira, Smart Protect, and Gluma increased the SBS of the zirconia restorations to dentin and can be recommended to use on prepared dentin surfaces prior to the cementation.

Evaluation of the Bond Strength, Durability, and Enamel Demineralization Potential of Orthodontic Adhesives on Bracket Bonding

ABSTRACT Objective: To evaluate the effects of incorporating titanium tetrafluoride (TiF4) into orthodontic primers on shear bond strength (SBS), bond durability, and enamel demineralization potential compared to conventional adhesive systems. Materials and Methods: In total, 120 extracted human premolars were divided into three groups (n = 40 each): Group A (Resin-based, Transbond XT), Group B (Glass ionomer-based, Fuji Ortho LC), and Group C (2 Wt.% TiF4-containing modified Transbond XT system). Standard edgewise premolar brackets were bonded to the teeth. Half of each group underwent immediate SBS testing, while the remaining specimens were thermocycled before testing. The Adhesive Remnant index was assessed post-debonding. Enamel demineralization was evaluated using quantitative light-induced fluorescence before bonding and after debonding. Results: Group C exhibited the highest mean SBS values both immediately (19.5 MPa) and after thermocycling (17.9 MPa). This group also showed the least enamel demineralization. Conclusions: The incorporation of 2 Wt.% TiF4 into the orthodontic primer resulted in improved bond strength and reduced enamel demineralization compared to conventional adhesive systems.

Effects of Adding Tricalcium Silicate Nanoparticles to the Universal G2 Bond Adhesive as Self-Etch Mode on the Shear Bond Strength to the Orthodontic Bracket.

This study investigated the effects of adding tricalcium silicate nanoparticles (TCSNp) to the universal G2 bond adhesive (G2BU) in self-etch (SE) mode on shear bond strength (SBS) to orthodontic brackets, cytotoxicity, and degree of conversion (DC). A total of 176 human teeth were divided into four groups based on TCSNp concentration in G2BU adhesive: 0% (control), 1%, 3%, and 5%. The G2BU adhesive consists of a hydrophilic primer (P) and a hydrophobic bonding agent (2B). TCSNp were added to the 2B component by mixing 0.1, 0.3, and 0.5 g of TCSNp with 9.9, 9.7, and 9.5 g of 2B, respectively. SBS was assessed after 24 h of water storage and 5000 thermocycles using a universal testing machine. Cytotoxicity was evaluated using the MTT assay on rat embryo fibroblast cells, and DC was measured using fourier-transform infrared spectroscopy. Statistical analysis included one-way ANOVA and Tukey's post-hoc test, with significance set at p < 0.05. After 24 h, mean SBS values were 15.58 MPa (control), 13.66 MPa (1% TCSNp), 15.99 MPa (3% TCSNp), and 12.04 MPa (5% TCSNp). After 5000 thermocycles, SBS values decreased to 12.91 MPa (control), 12.42 MPa (1% TCSNp), 11.11 MPa (3% TCSNp), and 10.21 MPa (5% TCSNp). ANOVA showed significant differences between groups (p < 0.05), except between the control and 3% TCSNp groups. Cell viability increased with higher TCSNp concentrations, with significant differences at 72 h between control and 5% TCSNp groups (p = 0.014). Mean DC values were 51.66% (control), 49.33% (1% TCSNp), 49.66% (3% TCSNp), and 48% (5% TCSNp). ANOVA indicated no significant differences between groups. Adding TCSNp to G2BU in SE mode maintains clinically acceptable SBS levels and enhances cytocompatibility. Higher TCSNp concentrations may reduce SBS and DC slightly. Further studies are needed to evaluate long-term effects.

Different adhesive approaches for the bonding of a new universal resin cement to a disilicate glass-ceramic.

This study aimed to evaluate the shear bond strength (SBS) when bonding a universal resin cement to a disilicate glass-ceramic using different adhesive protocols. Sixty specimens were etched with 10% hydrofluoric acid (HF) for 20s and assigned to one of four treatment protocols (n=15): The Positive control protocol comprised use of a universal adhesive system+adhesive resin cement; the Test1 protocol comprised use of a new universal adhesive system+universal resin cement; the Test2 protocol comprised use of a silane coupling agent+universal resin cement; and the use of a universal resin cement without adhesive and silane served as the Negative control. One of the two resin cement cylinders built on each specimen in each group was used to test for 24-h SBS, while the other was thermocycled and then tested for SBS. Data were submitted to two-way ANOVA, Tukey's test, and Weibull analysis. The negative control (24h) showed the lowest SBS mean value. The Test2 protocol resulted in the highest SBS mean value after thermocycling. Adhesive and mixed failures were prevalent in all groups. No statistical difference in m values was observed among the groups at 24h. After thermocycling, the two Test protocols showed the highest m values. The m values were significantly lower after thermocycling than at 24h for all groups. After thermal aging, The Test2 protocol resulted in a statistically significantly higher SBS mean value after thermal aging than seen for the other groups.

The effect of different treatment protocols on shear bond strength in resin composite restoration repair

BackgroundIt was aimed to investigate the effect of sandblasting and laser surface treatment on shear bond strength in composite restoration repair in vitro.MethodsA micro-hybrid composite (Filtek Z250, 3 M-ESPE, USA) was used to prepare 120 samples. The samples were subjected to a thermal cycle test 5,000 times between 5 and 55 0C, and they were randomly divided into 12 groups (n = 10). No surface treatment was performed in Groups 1 to 4, which were designed as control groups. The surfaces of the samples in Groups 5 to 8 were sandblasted with a Cojet device, and the surfaces of the samples in Groups 9 to 12 were applied Er, Cr: YSGG laser. After the sample surfaces were divided into groups with and without acid etching, universal adhesive was applied, and the repair process was performed using Filtek Z250 or nano-filled resin composite (Filtek Ultimate, 3 M-ESPE, USA). The thermal cycle test was repeated 5,000 times between 5 and 55 0C on all repaired samples. The repair shear bond strength of the samples was measured using a universal testing device (Shimadzu IG-IS, Kyoto, Japan). The fracture types were evaluated by optical microscopy and scanning electron microscopy (SEM). Statistical analyses of the findings were evaluated by the Kruskal Wallis test and Mann Whitney U test at 0.05 significance degree.ResultsThe highest mean shear bond strength values were obtained from the samples sandblasted with CoJet, followed by Er, Cr: YSGG laser, and the control group. It was determined that there was a significant difference between the mean shear bond strength values obtained from the control group and the other surface treatment groups (p < 0.05). In general, significantly higher mean shear bond strength values were obtained when the universal adhesive was applied in total-etch mode compared to the application in self-etch mode (p < 0.05). Additionally, it was determined that higher shear bond strength values were obtained with Filtek Ultimate compared to Filtek Z250 (p < 0.05).ConclusionWithin the limitations of this study, it can be concluded that the use of universal adhesive in total-etch mode, in addition to surface treatments on the resin composite surface in the repair protocol and the use of nano-filled resin composite as repair material can increase the mean shear bond values in repair.

Evaluation of the Conventional Acid-Etching System and the Self-Etching Primer in Bonding Metallic Orthodontic Brackets: An In-Vitro and In-Vivo Study.

This study aimed to compare the shear bond strength (SBS) of enamel-bonded orthodontic brackets with the conventional acid etching (CAE) system and the self-etching primer (SEP)in vitro and to compare the clinical performance of both systems when used in the treatment of malocclusion patients. In the first part of the study, 40 extracted human premolars were randomly divided into two groups containing 20 teeth. The first group (the conventional enamel etching group) employed37% phosphoric acid before bonding the metallic brackets (0.022-inch slot, MBT prescription, American Orthodontics, Sheboygan, WI, USA). The etching system wasTetric 5th (Ivoclar Vivadent, Schaan, Liechtenstein). The second group used a SEP (Sep Tetric 7th, Ivoclar Vivadent, Schaan, Liechtenstein) to bond the same brackets. In the first part of the study, SBS was evaluated, followed by the adhesive remnant index (ARI) assessment. The second part of the study (i.e., the clinical part) assessed a cohort of 30 patients during a 6-month observation period. The upper 10 teeth (from the second premolar on the right side to the second on the right side) were bonded using the chosen method for each patient in the clinical assessment. That is, 150 teeth in each group were evaluated regarding the failure rate. The ARI was assessed for those teeth that lost their brackets. The mean SBS was greater in the SEP group compared to the CAE group (17.93 MPa and 16.60 MPa, respectively; P = 0.014). The difference was not statistically significant. Conversely, the failure rate was lower in the CAE group compared to the SEP group, with a failure rate of 6% and 14.7%, respectively. The difference was statistically significant (P = 0.014). However, the ARI showed no statistically significant difference in in-vivo and in-vitro analyses, as most bracket failures were at the adhesive level. Laboratory results showed no statistical difference in the SBS mean values between the two groups. Clinically, the SEP group showed a greater failure rate than the CAE group, but both failure rates in the two groups were within the clinically acceptable range. The ARI did not show any difference between the two groups in terms of the failure site when the evaluation was conducted in vivo and in vitro, as most of the areas of failure were concentrated in the material itself.

The effect of addition of Bioglass 45S5 to orthodontic adhesive on shear bond strength of metal orthodontic brackets, An in vitro study

Aim: This study aimed to evaluate the effect of incorporating Bioglass (BG) 45S5 into an orthodontic adhesive on the shear bond strength (SBS) of metal orthodontic brackets bonded to enamel and the adhesive remnant index (ARI) score. Methods: In this in vitro study, 55 extracted sound premolars were randomly divided into five groups (n=11 each). Metal brackets were bonded using Ambar FGM orthodontic adhesive without BG (control group) and with BG 45S5 added at concentrations of 5%, 10%, 15%, and 20% by weight in groups 2 to 5, respectively. The SBS was measured using a universal testing machine, and the ARI score was determined under a stereomicroscope at ×10 magnification. Data were analyzed using one-way ANOVA at a significance level of α=0.05. Results: The highest mean SBS was observed in the 20% BG Group (48.28±24.5 MPa), followed by the control group (35.81±11.11 MPa), 15% BG Group (19.64±5.42 MPa), 10% BG Group (16.3±9.33 MPa), and 5% BG Group (14.21±4.23 MPa). The SBS in the 20% BG Group was significantly higher than in the control (P=0.013), 5% BG (P=0.000), and 10% BG (P=0.002) groups. No significant differences were found in ARI scores among the groups (P=0.810). Conclusion: Adding BG 45S5 to the orthodontic adhesive at concentrations of 5%, 10%, and 15% did not significantly affect the SBS, but a 20% concentration increased the SBS. Incorporating BG at these levels does not adversely impact the SBS or ARI scores.

Experimental and Chitosan-Infused Adhesive with Dentin Pretreated with Femtosecond Laser, Methylene Blue-Activated Low-Level Laser, and Phosphoric Acid.

Aim: To prepare experimental adhesive (EA) with 1% and without chitosan nanoparticles on dentin conditioned with a conventional technique phosphoric acid (PA) compared with two different contemporary techniques: photodynamic therapy (PDT) and femtosecond laser (FSL). Method: The methodology consisted of synthesis of EA and 1% chitosan-modified adhesive (CMA). Scanning electron microscopy, dentin adhesive interface assessment, energy-dispersive spectroscopy, shear bond strength (SBS), degree of conversion (DC), and bond failure were assessed. Teeth were selected, disinfected, and mounted in acrylic up to the cementoenamel junction. Occlusal enamel was removed and teeth were randomly allocated into groups and conditioned. These included Group 1: samples treated with PA; Group 2: specimens conditioned with methylene blue photosensitizer (MBP) activated by PDT; and Group 3: samples conditioned with FSL. Following different conditioning regimes, specimens were bonded using 1% CMA and EA. The composite buildup was followed by SBS testing and a bond failure assessment. DC was assessed for both EA and CMA. Analysis of variance and Tukey's post hoc test were used to compare the mean and standard deviation of SBS and DC in different experimental groups, with a significance level of p < 0.05. Results: Dentin pretreated with etch and rinse demonstrated the highest bond strength with 1% CMA. Dentin conditioned with MBP activated by PDT and bonded to EA showed the lowest bond scores. Overall SBS values of 1% CMA were better than EA irrespective of the conditioning regime of dentin. The DC was higher in EA adhesive. This was followed by DC in 1% CMA. DC in EA was found to be comparable with 1% CMA. Conclusions: PA remains the gold standard for dentin conditioning. The incorporation of 1% chitosan in adhesive improves SBS and results in no change in DC. The use of FSL in dentin conditioning can be used as an alternative approach as it results in SBS within acceptable limits. The study was approved by the ethical board of King Saud University.

Effect of different universal adhesive application protocols on shear bond strength of bulk fill composite to resin modified glass ionomer

Abstract Aim To evaluate the shear bond strength (SBS) of bulk fill composite to resin modified glass ionomer cement (RMGIC) after different universal adhesive application protocols. Patients and methods Thirty RMGIC (Ionoseal) discs are prepared using split Teflon mold with central holes 5 mm in diameter and 2 mm in height that were randomly divided according to different universal adhesive application protocols into three equal groups (10 each) as fallow: group I: Bulk fill composite was immediately placed without any treatment over RMGIC using another split Teflon mold with central holes 3 mm in diameter and 2 mm in height. Group II: Bulk fill composite was placed on RMGIC after treating of RMGIC discs with universal adhesive (Futurabond U). Group III: Bulk fill composite was placed on RMGIC after treating of RMGIC discs with 35% phosphoric acid and Futurabond U. Samples were thermocycled for 5000 cycles. SBS was measured using universal testing machine and the nature of the fracture was determined using stereomicroscope. Data was collected and analyzed statistically at a significance level of P less than 0.05. Results The highest mean SBS was recorded in group III followed by group II, while the lowest SBS was in group I. Samples in group I showed statistical significant differences versus both group II and III with P value 0.021 and less than 0.001, respectively, while there is no statistically significant difference when comparing SBS values of group II versus group III with P value 0.227. All the tested samples revealed only mixed failure mode. Conclusions Using universal adhesive system in sandwich technique provide a reliable bond between RMGIC and bulk fill composite than without any adhesive treatment. Using universal adhesive in total-etch mode improve the bond strength between the tested material but without significant effect compared to self-etch mode.

Comparison of Microleakage and Bond Strength in Metal and Ceramic Brackets Cured by Conventional and Transillumination Methods: An In-vitro Evaluation.

The study explores the impact of microleakage on bracket (metal/ceramic) debonding and the occurrence of white spot lesions during orthodontic treatment. Various curing techniques are employed to assess shear bond strength (SBS) and microleakage in both metal and ceramic brackets. A total of 120 samples were divided into six groups, each consisting of 20 samples. The groups were categorized based on the bracket material (metal or ceramic) and further subdivided according to the light-emitting diode (LED) curing method (traditional, transillumination, or combination). Fifty percent (60 samples) of each group were allocated for SBS evaluation, while the remaining 50% (60 samples) were used for microleakage assessment. The buccal enamel surfaces of all teeth in the six groups were etched and coated with a uniform layer of sealant. Stainless steel and ceramic maxillary premolar brackets were affixed using Transbond XT adhesive and light-cured with an LED unit. SBS was measured using the Instron ElectroPuls E3000 universal testing machine, and microleakage was examined using a stereomicroscope. One-way analysis of variance (ANOVA) with Bonferroni post-hoc test revealed significant differences in SBS among the six groups. Group IV exhibited the minimum SBS mean (7.02 MPa), while group VI displayed the maximum SBS mean (21.73 MPa). Microleakage assessment demonstrated that group IV had a maximum depth of 0.26 mm using the transillumination method, whereas group VI showed a minimum depth of 0.14 mm with the combination technique. Brackets cured with a combination of conventional (5 seconds) and transillumination (5 seconds per bracket) methods exhibited significantly higher SBS. Conversely, group IV, cured solely with the transillumination technique (10 seconds per bracket), demonstrated the lowest strength. In terms of microleakage, group VI, treated with the combination technique, displayed the shallowest depth, while group IV, cured exclusively with transillumination, showed the greatest depth of microleakage. These findings underscore the importance of the curing method in influencing both SBS and microleakage, offering valuable insights for optimizing orthodontic bracket placement techniques. Lenin A, Anbarasu P, S SK, et al. Comparison of Microleakage and Bond Strength in Metal and Ceramic Brackets Cured by Conventional and Transillumination Methods: An In-vitro Evaluation. Int J Clin Pediatr Dent 2024;17(9):999-1003.

Does enamel deproteinisation with 10% papain affect shear bond strength of orthodontic adhesives: a randomised controlled trial.

To evaluate the effect of 10% papain as an enamel deproteinising agent on the shear bond strength (SBS) of three orthodontic adhesives: Transbond XT, resin-modified glass ionomer cement (RMGIC) and Biofix. Single-centre, double-blinded, split-mouth randomised controlled trial. Department of Orthodontics and Dentofacial Orthopaedics, Nair Hospital Dental College, Mumbai, India. A total of 20 participants requiring bilateral premolar extraction for fixed orthodontic treatment in both the maxillary and mandibular arches were included in this study. In total, 80 premolars from the above-mentioned participants were divided into four groups as follows: group A: Transbond XT deproteinised with 10% papain gel; group B: Biofix deproteinised with 10% papain gel; group C: RMGIC deproteinised with 10% papain gel; and group D: Transbond XT without enamel deproteinisation as a control group-bonded as instructed by the manufacturer. After deproteinisation, brackets were bonded and after a follow-up period of 28 days, the teeth were extracted. The SBS was then measured using the Universal Testing Machine. The force needed to shear the bracket was documented, and bond strengths were subsequently calculated in megapascals (MPa). The obtained results were subjected to statistical analysis and one-way ANOVA was performed to compare the mean SBS between the groups. Subsequently, pairwise comparisons were conducted using Tukey's post hoc test. There was a statistically significant difference in SBS among all groups (P = 0.002). The SBS of TransXT with deproteinisation increased significantly compared with TransXT without deproteinisation (P = 0.03). There was no statistically significant difference between the SBS of TransXT without deproteinisation and RMGIC (P = 0.47) and Biofix (P = 0.39), both with deproteinisation. The use of 10% papain for deproteinising enamel improved the SBS of all materials. Deproteinising improved the SBS of RMGIC and Biofix to the level of TransXT without deproteinisation.