Highest Mean Shear Bond Strength Research Articles

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.

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.

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.

In Vitro Evaluation Of The Effect Of Different Cleansing Agents On The Shear Bond Of Contaminated Zirconia Ceramics To Resin Cement

Aim: The aim of this in-vitro study was to evaluate the effect of different cleansing solutions on the shear bond strength of contaminated zirconia ceramic to resin cement. Materials and Methods: Fifty zirconia disc (Dental Direkt,YES Germany) of size 10mm x 3mm were fabricated and mounted in self-cure acrylic resin block using a customized jig. The samples (n=10) were grouped based on two cleansing solutions and sub grouped based on two contaminants. Group I (control), neither contaminated nor any cleansing solution used. Group IIA, contaminating with saliva, cleansed with water and Group IIB, contaminating with GC Fitchecker II, cleansed with water. Group IIIA, contaminating with saliva, cleansed with Zirclean and Group IIIB, contaminating with GC Fitchecker II, cleansed with Zirclean. Subsequently fifty composite buttons (5.5mm x 3mm) were fabricated and bonded to the test samples using resin modified glass ionomer cement (Riva Cem,SDI). Thermocycling, shear bond strength, scanning electron microscopy were carried out for all the groups. Statistical analysis was done using independent t test with SPSS software Results: On comparison it was found that samples contaminated with saliva, cleansed with Zirclean showed a higher mean shear bond strength and the result was statistically significant (P&lt;0.001). Samples contaminated with GC Fitchecker, cleansed with Zirclean showed a higher mean shear bond strength and the result was statistically significant (P&lt;0.001). The result collaborated with SEM analysis of the debonded samples. Conclusion: Zirclean can be used as an effective surface cleansing solution for zirconia restorations.

Influence of different endodontic irrigants on shear bond strength of composite resin to coronal dentin: An in vitro study

Objectives: Endodontic irrigants are critical in root canal treatments, but their influence on the coronal dentin bond strength of composite restorations is a key concern for a favorable clinical prognosis. The present in vitro study explores the effect of different endodontic irrigants on shear bond strength of composite resin. Material and Methods: Fifty permanent human mandibular molars were sectioned to expose coronal dentin and divided into five groups. Each group received a specific irrigant treatment before composite resin bonding. Shear bond strength was examined using Instron Universal testing machine, and statistical analysis was conducted using post hoc Tukey’s test and analysis of variance. Results: Group A (Saline) showed a mean shear bond strength of 18.5 Megapascal (MPa). Group B [sodium hypochlorite (NaOCl)] had mean shear bond strength of 15.2 MPa. Group C [Chlorhexidine (CHX) Gluconate] exhibited mean shear bond strength of 20.3 MPa. Group D ethylenediaminetetraacetic acid (EDTA) recorded mean shear bond strength of 14.8 MPa, while Group E [citric acid (CA)] had the highest mean shear bond strength at 22.7 MPa. Conclusion: The type of endodontic irrigant used significantly affected the shear bond strength of composite restorations to coronal dentin. CHX gluconate and CA displayed superior bond strengths compared to Saline, NaOCl, and EDTA. This underscores the importance of irrigant selection in achieving successful composite restorations in endodontically treated teeth.

The effect of orthodontic bracket base shape on shear bond strength to human enamel, an in vitro study.

The purpose of this study was to evaluate the in vitro effect of orthodontic bracket base shape on shear bond strength (SBS) to human enamel and assess the nature of debonding fractures using the Adhesive Remnant Index (ARI). Orthodontic brackets with different-shaped bases (flower, heart, rectangle) were bonded to 120 extracted human third molars. Shear bond strength was measured using a Servohydraulic Test System at 24 h and 2 months after bonding. Adhesive Remnant Index scores were evaluated under 10x magnification to assess the amount of resin left on the tooth. The control bracket (rectangular base shape) had the highest mean SBS (26.8 ± 8.2 megapascals [MPa]), and significantly differed from the flower (17.2 ± 4.4 MPa) and heart (18.9 ± 3.5 MPa) base shapes (p < 0.001). The mean SBS between debonding times at 24 h (21.5 ± 7.4 MPa) and 2 months (20.4 ± 6.7 MPa) were not statistically significant (p > 0.05). Analysis of ARI scores showed a significant difference between flower-24 h versus heart-2 months (p = 0.039), flower-24 h versus heart-24 h (p = 0.004), and control-2 months versus heart-24 h (p = 0.015). Bracket base shape influenced SBS, with the rectangular base shape having a higher mean SBS compared to flower and heart base shapes. Variations in ARI scores occurred based on bracket shape and were of a mixed adhesive-cohesive nature. All bracket shapes had bond strengths above the clinically acceptable range of 6-8 MPa, and may thus provide adequate SBS in a clinical situation.

Evaluation of shear bond strength of labial veneers after sandblasting/micro-abrasion of prepared teeth by aluminum oxide particles. An in-vitro study

ObjectivesTo explore the feasibility and effectiveness of using sandblasting with aluminum oxide particles to improve the shear bond strength of labial veneer restorations in dentistry. Materials and MethodsA sample size of 50 extracted teeth was divided into five groups, with each group containing ten teeth (n = 10) subject to different treatment protocols. Group 1the control group, underwent conventional surface treatment for labial veneer restorations, including the application of phosphoric acid etchant and bonding protocols. Groups 2 and 3 underwent micro-abrasion using aluminum oxide particles alone for durations of 30 and 45 s, respectively. Groups 4 and 5 experienced a combined approach of micro-abrasion for 30 and 45 s, respectively, followed by conventional surface treatment. The shear bond strength test was performed on each specimen. The resulting modes of failure and surface characteristics were then examined under a digital microscope.The data was analyzed statistically using a one-way analysis of variance (ANOVA) and a post hoc test. ResultsSignificant differences were observed in shear bond strength among the five groups (p < 0.05). The group that underwent conventional + 45-second micro-abrasion treatment exhibited the highest mean shear bond strength (25.69 MPa), while the conventional (controlled) group had the lowest (9.01 MPa). ConclusionFusing sandblasting and aluminum oxide particles could improve the bond strength of labial veneer restorations. Yet, more research is needed to refine this technique for practical application. This includes a broad array of cement types, particle sizes, and clinical situations to ensure the long-term success of veneer restorations.

Repair of bulk-fill composite after different surface treatments

Purpose To evaluate the effect of different surface treatments on the shear bond strength of repaired aged bulk-fill composites. Materials and method 60 cylindrical specimens of bulk-fill composite (X-tra fil) were prepared and stored in artificial saliva for 3 months. They were divided randomly into 2 groups according to the different repair material (n = 30), (I) X-tra fil and (II) Grandio. Then, they were further divided into 3 subgroups according to surface treatments (n = 10), (A) no surface treatment (B) diamond bur abrasion, and (C) air abrasion. Futurabond U adhesive was applied to all specimens, and then the repair composites were added. All specimens were subjected to thermo-cycling. They were tested for shear bond strength using a universal testing machine. Fractured samples were examined under a stereomicroscope to determine the mode of failure. An additional 30 specimens were made to evaluate the surface roughness. Representative SEM micrographs for each surface treatment were taken to assess the surface topography. All data was collected, tabulated and statistically analyzed. Results Group I: The highest mean shear bond strength was recorded in the group (IB) followed by (IC) and then (IA). Group (IA) was significantly different from groups (IB) and (IC) (P &lt; 0.05). Group II: The highest mean shear bond strength was recorded in the group (IIB) followed by (IIC) then (IIA). Group (IIB) was significantly different from group (IIA) (P &lt; 0.05). All surface treatments demonstrated significantly greater shear bond strength than not having any physical surface treatment. Repairing X-tra fil can be performed by either X-tra fil or Grandio with no statistically significant difference. Most of the specimens in all groups showed mixed and cohesive failures. Diamond bur abrasion showed the highest surface roughness values followed by air abrasion then control group. Conclusion The shear bond strength of repaired bulk-fill composite with bur or air abrasion was comparable and greater than no surface treatment. There was no significant difference between the two repair materials used.

Evaluation of the effects of different mouthwashes, acidic soft drinks, and herbal teas on shear bond strength of orthodontic stainless steel brackets: A stereomicroscopic study

Background: Premature debonding of brackets often turns out into orthodontic treatment failures and actual treatment delays. The aim of the present study was to evaluate the effects of different mouthwashes, acidic soft drinks, and herbal teas on the shear bond strength of metal (stainless steel) brackets used in orthodontic practice. Materials and methods: For the present study, 100 therapeutically extracted healthy premolar teeth with sound enamel surface were collected from patients who were scheduled for orthodontic treatment. The select teeth were cleansed, whereas the dried enamel surface was etched with 38% phosphoric acid for 15 s following which orthodontic stainless steel brackets (MBT 0.022 SLOT) were bonded with the help of composite resin (3M Unitek Transbond XT Light Cure Adhesive). The prepared teeth were divided into four groups depending on exposure to different mouthwashes, acidic soft drinks, and herbal teas. The shear bond strength values of the specimen were measured using a universal testing machine, whereas debonded surfaces were observed under a stereomicroscope. Statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc., Chicago, IL, USA). One-way analysis of variance and Tukey’s multiple post hoc procedures were used for statistical analysis. P &lt;0.05 was considered statistically significant. Results: The results obtained in the present study suggested that the highest mean shear bond strength observed was in case of Group II specimen with a mean value of 11.83 ± 1.92 MPa, whereas the least shear bond strength was observed in case of Group III specimen with a mean value of 10.33 ± 1.31 MPa, with the results being statistically significant (P = 0.014). Conclusions: Within the limitations of the present study, it was concluded that comparatively lesser/weaker shear bond strength values were observed in case of specimen belonging to Group III, wherein among the 30 teeth belonging to Group III, 12 teeth showed shear bond strength value of 9 MPa which was the lowest in the study. The following core competencies are addressed in this article: Practice-based learning and improvement, Patient care and procedural skills, Systems-based practice, Medical knowledge.

Influence of different immediate dentin sealing strategies on bond strength of indirect resin nanoceramic restorations.

In this study, we evaluated the effect of four different strategies for bonding a CAD/CAM resin nanoceramic restoration (Lava Ultimate, 3M) to the dentin surface using a universal adhesive (Scotch Bond Universal, 3M) and adhesive resin cement (RelyX Ultimate, 3M) on the shear bond strength (SBS) and failure mode. The strategies comprised: (i) immediate sealing, immediate bonding; (ii) immediate sealing, bonding after 2weeks with provisional restoration; (iii) immediate sealing with flowable resin composite reinforcement and bonding after 2weeks with provisional restoration; and (iv) no immediate sealing, and bonding after 2weeks with provisional restoration. After bonding, all the specimens were thermocycled, shear tests were performed using a universal testing machine, and failure modes were determined using stereomicroscope and scanning electron microscopy. The highest mean SBS was recorded with immediate sealing, immediate bonding strategy. Most adhesive failures with exposed dentinal tubules were noted in specimens exposed to bonding after 2weeks with no immediate sealing, which was associated with the lowest SBS. Mixed failures predominated in all immediate dentin sealing groups. Immediate sealing with universal adhesives improves SBS, particularly in the single-visit approach, which has shown significantly better performance, whereas the provisional phase has a negative effect.

Effect of Aging and Different Surface Treatments on Repair Bond Strength of Hybrid Resin Composites

Background: With the trend for minimally invasive dentistry and the rapid evolution of composite resin materials, repair of defective composite resin restorations is a popular choice rather than replacement of the restoration. The durability of the bond between the old and repaired composite restoration is important for a successful outcome. Objective: To evaluate the immediate and delayed shear bond strength of two types of repaired hybrid resin composites using different chemical and mechanical surface treatments. Methods: Two types of hybrid resin composites, micro-hybrid resin composite and nanohybrid resin composite, were used to prepare 288 pre-polymerized resin composite specimens. After polymerization, repair was done after 24 hours and 6 months. Each hybrid resin composite group was divided into 3 groups according to surface treatment used to repair the substrate: group 1: no surface treatment, group 2: treated by medium abrasive stone, and group 3: treated by fine abrasive stone. Each group was further subdivided into 3 subgroups according to different agents used for repair: group 1: Silane, group 2: Universal adhesive, and group 3: Silane + adhesive. Shear bond strengths of the repaired specimens were measured using a Universal testing machine. Failure modes were evaluated under a stereomicroscope. Results: Different chemical and mechanical surface treatments had a significant effect on the shear bond strength values of all groups (p ≤ 0.05). The highest mean shear bond strength values were found in nano-hybrid composites immediately repaired by silane after treatment by a medium abrasive stone while the lowest mean shear bond strength values were found in micro-hybrid composites with delayed repair and no surface treatment. Conclusion: Diamond burs using silane with adhesive improved the repair bond strength of the tested hybrid composites. In composite repair, using abrasive mechanical pretreatment followed by adhesive conditioning is crucial for the success of the repair restoration.

Evaluation of the effect of mechanical alteration of enamel surface on shear bond strength of self-adhering composites utilizing different adhesive modalities

Abstract Background: Self-adhering flowable composite (SAC), which has currently been launched, is said to be postoperatively responsive and less technique-reactive than previous materials. Clinical demands for bonding to undamaged, modified, or prepared enamel surfaces—which may attach differently with adhesive resins—often accompany restorative demands. Very little information was available for SAC. Aim: This study was carried out to determine the impact of mechanical enamel surface modification on shear strength properties in various bonding procedures. Materials and Methods: The three groups of prepared enamel surfaces (group A, n = 60), unprepared enamel surfaces (group B, n = 60), and prepared enamel surfaces plus etch-and-rinse (group C, n = 20), which served as the control group, were randomly assigned to the 140 constructed samples. Subgroups A1, B1 (nanohybrid composite + self-etch), A2, B2 (self-adhering composite), and A3, B3 (self-adhering composite + self-etch) were created from groups A and B, respectively (n = 40). Composite resin cylinders with the unique bonding protocols of each group were created using Teflon ring molds. Testing for shear bond strength was done, and information was examined. Results: The control group C was found to have the highest mean shear bond strength (29.77 MPa), whereas subgroup B2 had the lowest mean shear bond strength (8.4 MPa). For all adhesive techniques, shear bond strength values for prepared enamel surfaces were considerably greater than those for unprepared enamel surfaces (P &lt; 0.01). The following were the mean shear bond strength values: C &gt; A1 &gt; A3 &gt; A2 &gt; B1 &gt; B3 &gt; B2. Conclusions: Shear bond tensile properties on prepared enamel surfaces were higher than those of unprepared enamel surfaces. Higher shear bond strength values of the self-adhering composite in prepared and unprepared enamel surfaces were produced by using a self-etch agent first.

A Study to Evaluate the Effect of Cleaning Solutions on Shear Bond Strength of Resin Cement to Saliva-Contaminated Lithium Disilicate (LDS) Ceramic.

One of the greatest benefits of contemporary restorative dentistry is the creation of fixed partial dentures. The retention and durability of the fixed partial dentures may be improved by using a variety of tooth preparation methods, surface treatments, and luting resins. To measure the shear binding strength of resin cement to saliva-contaminated lithium disilicate (LDS) ceramicafter being exposed to various cleaning treatments. Over 30 LDS samples were examined. In Group 1, a cleansing solution comprising 15% zirconium oxide (Ivoclean) was employed for a duration of 20 s. This was succeeded by a rinsing phase lasting 15 s utilizing deionized water, followed by a 15-s period for drying. Subsequently, a final stage of air drying was conducted over a span of 15 s.In contrast, Group 2 underwent a washing procedure of 20 s involving a cleansing solution containing 30% sodium silicate. This was then ensued by a rinsing interval of 15 s with deionized water, succeeded by an air-drying process spanning 15 s. After applying cleaning solutions to the surface and adhering the specimens to the composite blocks using resin cement Multilink Automix (Ivoclar Vivadent, Schaan, Liechtenstein), the shear bond strength was assessed. Using a 30% sodium silicate solution (Group 2), we were able to get the highest mean shear bond strength value after saliva-contaminated LDS. Group 1, 15% zirconium oxide (Ivoclean) had the weakest decontamination agents as measured by mean shear bond strengths. The shear bond strength values of the two groups were found to vary significantly between individuals using the independent sample t-test. LDs ceramic cleaned with a 30% sodium silicate solution had a higher shear bond strength than ceramic cleaned with Ivoclean (p<0.05). The application of a 30% sodium silicate solution rendered the highest shear bond strength for saliva-contaminated LDS ceramic. In comparison, ceramic cleaned with Ivoclean exhibited notably lower shear bond strength values. The outcome of this investigation highlights the potential of diverse cleaning agents in influencing the adhesive qualities of resin cement, thereby contributing to the enhancement of fixed partial denture durability and efficacy.

Effect of Different Chemical Surface Treatments on the Shear Bond Strength of Acrylic Teeth With Different High-Impact Denture Base Resins.

Introduction The debonding of acrylic teeth from the denture base, particularly in cases of prominent ridges, is a common problem faced by clinicians and patients. The present study was conducted to assess the effects of various chemical treatments on the shear bond strength (SBS) of acrylic teeth bonded to different high-impact denture base materials. Materials and methods The present in vitro study was conducted on 80 wax specimens with acrylic teeth bonded to two high-impact denture base materials (DPI Tuff (DPI Dental Products of India Ltd, Mumbai) and Trevalon HI (Trevalon HI, Dentsply, Karnataka)). The two main groups were further divided into four subgroups of 10 specimens each, depending on the chemical treatment at the ridge lap area of the tooth: control group without any chemical treatment, chemical surface treatment (CST) with dichloromethane and monomer mix, CST with ethyl acetate, and CST with acrylic adhesive cyanoacrylate. The SBS was tested using a universal testing machine (UTM). Analysis of variance (ANOVA) and post-hoc Tukey tests were used for statistical analyses. Results The mean SBS of Group A (DPI Tuff) was 111.75 Nas compared to 118 N in Group B (Trevalon HI). The differences were statistically significant (p<0.05). ANOVA and post-hoc Tukey's tests revealed significant differences between subgroups. The highest mean SBS was noted with a dichloromethane and monomer mix (1:1 volume), followed by the ethyl acetate, control, and cyanoacrylate subgroups. Conclusion The cross-linked acrylic teeth treated with a dichloromethane and monomer mixture (1:1 by volume), processed with Trevalon HI high-impact denture base resin had the highest SBS and thus were indicated for bonding teeth with the suggested denture base.

Does the Duration of Acid Treatment Affect the Bond Strength Between Resin Cement and Zirconia

Statement of the problem: The bonding between the resin cement and zirconia still needs to be improved and the effect of the experimental acid application duration on the resin bond strength with zirconia is unk-nown. Objective: This study aimed to investigate the effect of different acid application times on the shear bond strength between zirconia and dual-cure resin cement. Materials &amp; Methods: A total of 50 zirconia disks were prepared in 2 mm thickness and randomly divided into five treatment groups: control (no treatment was applied), 30 seconds HF:H2O:H2O2 acid application group, 60 seconds HF:H2O:H2O2 acid application group, 90 seconds HF:H2O:H2O2 acid application group, and 120 seconds HF:H2O:H2O2 acid application group. Then a dual-cure resin cement was applied over the 3 mm diameter and 3 mm thickness of the zirconia specimens. The speci-mens were immersed in distilled water and maintained at a temperature of 37°C for a duration of 24 hours. The shear bond strength tests were perfor-med using a universal testing machine with a force of 1 mm/min until the fracture occurs, and the data were analyzed using one-way ANOVA and Tukey's post-hoc test. Results: The highest mean shear bond strength was found in the 90 seconds acid application group, which was significantly higher than the control and 30 seconds acid application groups (P&lt;0.05). However, the 60- and 120 seconds acid application groups showed similar shear bond strength values with the control, 30- and 90 seconds acid application groups (P&gt;0.05). Conclusions: The use of a 60-, 90- and 120 seconds acid application can improve the bond strength between zirconia and resin cement. However, caution should be taken when using this acid due to its potential toxicity and hazards.

To Compare and Evaluate the Shear Bond Strength of Sixth- and Seventh-generation Bonding Agents.

To compare and evaluate the shear bond strength of sixth and seventh-generation dentin bonding agents. Around 75 extracted permanent mandibular premolars were selected and assigned into two groups. The samples were cleaned, cavities were prepared, and the bonding agent was applied and stored in distilled water for 24 hours. Shear bond strength testing was done using a universal testing machine at the crosshead speed of 1 mm/minute. Data were analyzed statistically by one-way analysis of variance (ANOVA) and paired test. The greatest mean shear bond strength to dentin was exhibited by the sixth-generation dentin bonding agent due to the solvent present, which has a low concentration and low hydrophilicity than the seventh-generation. Sixth-generation adhesives showed significantly higher mean shear bond strength to dentin than seventh-generation adhesives. Bond strength values are gross assessing tools for evaluating the efficacy of restorative bonding materials to dentin. And as the shear bond strength is less technique sensitive to perform, it will highlight the strength at the bonded interface. Adyanthaya BR, Gazal S, Mathur M, et al. To Compare and Evaluate the Shear Bond Strength of Sixth- and Seventh-generation Bonding Agents. Int J Clin Pediatr Dent 2022;15(5):525-528.

The effect of mechanical and chemo-mechanical temporary cement cleaning methods on shear bond strength with self-adhesive resin cement (an in-vitro study)

BackgroundAdhesive tooth-colored restorations are strongly dependent on the substrate surface cleanliness to allow intimate contact between resin cement and dentin surface, so several methods were adopted for the total cleaning of temporary cement residues. This study aimed to assess the effect of mechanical and chemo-mechanical cleaning methods of temporary cement on the immediate shear bond strength of self-adhesive resin cement to dentin surface.MethodsForty freshly extracted lower first premolars were cut to expose a flat dentin surface. Discs of temporary crown composite resin material were constructed and cemented to the flat dentin surface using resin-based and non-eugenol temporary cement then stored at room temperature in distilled water. Dividing of samples into two groups according to the method of temporary cement cleaning. Group I (n = 20) mechanical cleaning using the rotary instrument, and group II (n = 20) chemo-mechanical cleaning using chlorhexidine-containing scrub. CAD/CAM reinforced Composite discs were bonded to the dentin surface using self-adhesive composite resin cement, then measurement of shear bond strength was done using a universal testing machine. Further analysis of failure mode after debonding was performed by Scanning electron microscope.ResultsNo statistically significant difference was found between the mean shear bond strength of the two cleaning methods (P-value = 0.636). Regardless of the cleaning method, the group cemented with resin-based temporary cement showed statistically significantly higher mean shear bond strength than non-eugenol temporary cement (P-value = 0.048).ConclusionBoth cleaning methods (mechanical and chemo-mechanical) applied in this study were effective in cleaning temporary cement remnants from the dentin substrate surface with statistically significant differences between results of shear bond strength with significantly higher values recorded with resin-based temporary cement.

Evaluation of the shear bond strength and adhesive remnant index of color change, fluorescent, and conventional orthodontic adhesives: An in vitro study

To investigate the in vitro performance of colour change orthodontic adhesive (CCOA) or fluorescent orthodontic adhesive (FOA), conventional orthodontic adhesives (COA), and the mixed CCOA and FOA utilizing the shear bond strength (SBS) and adhesive remnant index (ARI). Ninety extracted first premolars were used in the study. Four manufacturers of orthodontic adhesive were used, including Transbond™ XT (TBXT) and Transbond™ plus (TBP) (3M™ Unitek™, CA, United States), Ormco Enlight™ (OE) and Greengloo™ (GG) (Ormco™, CA, United States), Light Bond Medium™ (LBM), and GoTo™ (GT) (Reliance orthodontic products®, IL, United States), and BracePaste® Adhesive (BPA) and BracePaste® Colour Change (BPCC) (American orthodontics®, WI, United States). The mixed orthodontic adhesive of Transbond™ plus and GoTo™ (TBPGT) was prepared to evaluate the combined effect of colour change and fluorescent orthodontic adhesives. Peak SBS was recorded using a universal testing machine. ARI was measured using a stereomicroscope under 10x magnification. Descriptive statistical analysis and comparative tests were used to evaluate the results. All CCOA and FOA had higher mean SBS than COA. The highest value of SBS was obtained in BPCC (23.56MPa), and the lowest value in TBPGT (11.41Mpa). One-way ANOVA multiple comparisons and Duncan's multiple range test showed that TBXT and TBPGT significantly differed in SBS with GT, GG, TBP, and BPCC, respectively (P=0.016). Kruskal-Wallis multiple comparisons test showed no significant differences in ARI among the tested adhesives (P=0.089). Colour Change Orthodontic Adhesive (CCOA) and Fluorescent Orthodontic Adhesive (FOA) showed a higher SBS than conventional orthodontic adhesives. GreenglooTM had the lowest ARI among the groups tested. All adhesives tested can be safely used in orthodontic practice, and both CCOA and FOA showed better performance than COA. The TransbondTM plus and GoToTM (TBPGT) mixed adhesives showed the lowest performance in terms of SBS and ARI.

Clinical in-situ evaluation of the effect of rubber dam isolation on bond strength to enamel.

To evaluate the effect of rubber dam isolation on shear bond strength of two different adhesive systems to enamel. The mesial, distal, lingual, and vestibular enamel surfaces of thirty human third molars were prepared (total n= 120). A custom splint was made to fit a volunteer's maxilla, holding the specimens in place in the oral cavity. Four composite resin cylinders were bonded to each tooth with one of two bonding agents (OptiBond FL and Prime&Bond active) with or without rubber dam isolation. Shear bond strength was tested in a universal testing machine and failure modes were assessed. Significance level for statistical analyses was set at 5%. All pairwise comparisons revealed statistical differences (p< 0.05). The highest mean shear bond strength values were obtained in rubber dam experimental groups, regardless of the adhesive system. Group OptiBond FL with rubber dam presented the highest mean bond strength values. Fracture modes for specimens bonded without rubber dam isolation were adhesive and cohesive within enamel, while rubber dam experimental groups revealed only cohesive fractures. Absolute isolation with rubber dam increases bond strength to enamel, independent of the adhesive system. The three-step total-etch system OptiBond FL provided significantly higher bond strength values than Prime&Bond active under both experimental conditions. Rubber dam isolation has a significant effect on bond strengths to enamel, independent of the adhesive system. Its application is, therefore, advised whenever adhesive procedures are performed. A filled three-step etch-and-rinse adhesive performed superiorly, with or without rubber dam isolation, when bonding to enamel compared to an isopropanol-based universal adhesive.

Effect of Sandblasting with Fluorapatite Glass-ceramic Powder and Chemical Primers/Adhesives on Shear Bond Strength of Indirect Repairing Composite to Zirconia.

To investigate the effect of sandblasting with fluorapatite glass-ceramic (FGC) powder on zirconia surface roughness, crystallinity, and shear bond strength (SBS) of indirect repairing composite to zirconia using different primers/adhesives. Zirconia blocks were treated as follows: no treatment (control group), blasting with 30-μm silica-coated alumina (CoJet group), and blasting with FGC powder (FGC group). The surface topography, silica content, roughness, and crystallinity of treated zirconia surfaces were analyzed by a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), an optical profilometer, and X-ray diffraction (XRD), respectively. Four primers/adhesives (Monobond Plus, Calibra Silane, Futurabond M+, and Scotchbond Universal) were compared to bond precured resin composite to zirconia groups using Multilink Automix resin cement. Bonded specimens were thermocycled for 10,000 cycles and tested in SBS and the modes of failure were recorded. The effect of different surface treatments and primers/adhesives on SBS results were statistically analyzed using two-way ANOVA and Bonferroni post-hoc tests (α=0.05). Both CoJet and FGC groups showed rough surfaces with a higher content of silica in FGC, but less monoclinic crystals, compared to the CoJet group. The highest mean SBS was found in the FGC group treated with Monobond Plus compared to CoJet and Control groups. Adhesive failure was predominant in control groups, while combined failure was found in the CoJet and FGC groups regardless of the primers/adhesives employed. Sandblasting zirconia with FGC powder increased SBS of resin composite to zirconia with lower monoclinic phase transformation compared to CoJet sand. Monobond Plus reported the highest means of SBS values compared to other primers/adhesives.