Mean Shear Bond Strength Research Articles

Effects of Surface Treatments and Cement Type on Shear Bond Strength between Titanium Alloy and All-Ceramic Materials.

This study aimed to evaluate the effects of surface treatments and resin cement on the adhesion of ceramic and ceramic-like materials to titanium. A total of 40 specimens (5 mm diameter) of each material (lithium disilicate glass ceramic (LDGC-IPS e.maxCAD), lithium silicate glass ceramic (LSGC-VITA Suprinity) and a polymer-infiltrated ceramic network (PICN-Vita Enamic)) were fabricated using CAD/CAM technologies. In total, 120 titanium (Ti) specimens were divided into 12 groups, and half of the titanium specimens were tribochemically coated using CoJet. The titanium and all-ceramic specimens were cemented using either Self-curing adhesive cement (SCAC-Panavia 21) or a Self-curing luting composite (SCLC-Multilink Hybrid Abutment). After 5000 cycles of thermal aging, the shear bond strength (SBS) test was conducted using a universal testing machine. The failure modes of the specimens were analyzed using stereomicroscopy, and additionally, the representative specimens were observed using Scanning Electron Microscopy. ANOVA was used for the statistical analysis (p < 0.05). The post-hoc Duncan test was used to determine significant differences between the groups. The mean SBS values (mean ± STD) ranged from 15 ± 2 MPa to 29 ± 6 MPa. Significantly higher SBS values were acquired when the titanium surface was tribochemically coated (p < 0.05). The SCLC showed higher SBS values compared to the SCAC. While the LDGC showed the highest SBS values, the PICN presented the lowest. The tribochemical coating on the cementation surfaces of the titanium increased the SBS values. The specimens cemented with the SCLC showed higher SBS values than those with the SCAC. Additionally, the SCLC cement revealed a more significant increase in SBS values when used with the LDGC. The material used for restoration has a high impact on SBS than those of the cement and surface conditioning.

Comparison of the Shear Bond Strength of Orthodontic Composites Containing Silver and Amorphous Tricalcium Phosphate Nanoparticles: an ex vivo Study.

It is important to use orthodontic composites with favorable properties, which are easily removed after the end of the treatment but not easily debonded during treatment. Nanoparticles have drawn attention for their antibacterial properties when added to composite resins. However, the effect of addition of nanoparticle on shear bond strength is not broadly discussed. The present study was designed to compare the shear bond strength of orthodontic brackets bonded by orthodontic composite containing silver nanoparticles with orthodontic composite containing amorphous tricalcium phosphate nanoparticles. In this ex vivo study, 36 sound extracted human premolars were used and randomly divided into three groups. The brackets were bonded in the first group by composite without nanoparticles, in the second group by composite containing 3% amorphous tricalcium phosphate nanoparticles and in the third group by composite containing 0.3% silver nanoparticles at the buccal surface of the teeth. The shear bond strengths of the samples were measured 24 hours after preparation by a universal testing machine. Data were analyzed using SPSS 21 software through one-way ANOVA and Tamhane's T2 multiple comparison tests. pValues under 0.05 were considered significant. There was no significant difference between the mean shear bond strength of composite containing amorphous tricalcium phosphate nanoparticles with composite without nanoparticles (p= 0.142). However, the mean shear bond strength in the composite containing silver nanoparticles was significantly lower than the other two groups (p< 0.001). According to the results of this study, the addition of amorphous tricalcium phosphate nanoparticles to orthodontic composite does not significantly decrease the shear bond strength while silver nanoparticles reduce the shear bond strength of orthodontic composite.

Bonding performance of glass ionomer cement to carious dentin treated with different surface treatment protocols using silver diamine fluoride

This study investigated the influence of silver diamine fluoride (SDF) on the shear bond strength (SBS) to artificial carious dentin and GIC restorations with various SDF application protocols. Artificial caries were prepared on human dentin discs using bacteria model. These samples were randomly allocated to five groups (n = 10/group) according to the following treatment: (1) control group (CD): no treatment (2) CSR: dentin conditioner, SDF, and rinsing (3) CS: dentin conditioner and SDF (4) SRC: SDF, rinsing and dentin conditioner, and (5) SC: SDF and dentin conditioner. The treated-dentin surface was bonded with GIC and subjected to SBS test. Mean SBS was analyzed using one-way ANOVA. Surface morphology and elemental contents after surface treatment were examined (n = 3/group) by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). There was no significant difference in the mean SBS among CD (2.45 ± 0.99 MPa), CSR (1.76 ± 0.65 MPa), and SRC (2.64 ± 0.95 MPa). Meanwhile, the mean SBS of CS (0.35 ± 0.21 MPa) was significantly lower than the control and SRC group. SEM/EDX demonstrated deeper silver penetration in CSR and CS groups when compared to SRC and SC groups. SDF-modified GIC restorations resulted in significantly lower bond strength in CS and SC groups. The findings suggested treating the carious dentin surface with CSR and SRC protocol. SDF-treated carious dentin should be rinsed off prior to restore with GIC.

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.

The Effect of Salivary Contamination on the Shear Bond Strength of Seventh- and Eighth-generation Adhesive Systems.

To compare the effect of salivary contamination on the shear bond strength (SBS) of seventh- and eighth-generation adhesives. Specimens were randomly divided into group I and group II, subdivided into three subgroups of 11 samples. Subgroup IA-seventh-generation uncontaminated (control); adhesive; air-dried; light cured. Subgroup IB-seventh-generation adhesive; saliva application, air-dried; light cured. Subgroup IC-seventh-generation adhesive; saliva application, air-dried, reapplication of adhesive, air-dried, light cured. Subgroup IIA- eighth-generation uncontaminated (control); adhesive, air-dried; light cured. Subgroup IIB- eighth-generation adhesive; saliva application, air-dried; light cured. Subgroup IIC-eighth-generation adhesive, saliva application, air-dried, reapplication of adhesive, air-dried; light cured. Following bonding procedure, composite resin restoration was done and subjected to SBS analysis. Mean SBS of eighth-generation adhesive was higher compared to seventh with and without saliva contamination. Reduction of SBS in seventh- and eighth-generation after saliva contamination was regained by reapplication of adhesive, which was less compared to the control [statistically significant (p < 0.05) for seventh and statistically not significant for eighth-generations]. The eighth-generation adhesives show better SBS with and without saliva contamination and reapplication of eighth-generation adhesives significantly improved the SBS close to the control. Single-step self-etch adhesives are the adhesives which are currently used for bonding composite restorations to dentin. The adhesive bond strength can be adversely affected by moisture contamination, especially by saliva, which can lead to failure of restoration. So, it is imperative to study a material which gives better bond strength and is less affected by salivary contamination and effect of decontamination to regain the bond strength. The study concluded that eighth-generation adhesives showed higher mean SBS with and without saliva contamination and reapplication of eighth-generation adhesives significantly improved the bond strength close to the control group. Mohan MC, Geetha P, Soman D, et al. The Effect of Salivary Contamination on the Shear Bond Strength of Seventh- and Eighth-generation Adhesive Systems. Int J Clin Pediatr Dent 2023;16(S-1):S63-S66.

The Effect of Bonding Surface Design on Shear Bond Strength of 3D-Printed Orthodontic Attachments.

This study compared the shear bond strength (SBS) of four innovative designs of the bonding surface of 3D-printed orthodontic attachments with conventional mesh design. In this in vitro study, the bonding surface design in different groups was as follows: Group 1, flat surface without any feature as a negative control; Group 2, concentric circles with no cuts; Group 3, concentric circles with 16 radial cuts; Group 4, concentric circles with 32 radial cuts; Group 5, small cones with a flat end and rounded edges; Group 6, mesh-based commercially available metal brackets of the maxillary central incisor (standard edgewise, Dentaurum®) as a positive control (n = 20). In Groups 1-5, attachments were designed with SolidWorks® Software and printed with a 2K DLP-LCD printer with hard tough resin (eSun®). All the samples were bonded to the restorative composite resin (Solafil®) surfaces with orthodontic composite resin (CuRAY-ECLIPSE®). The samples were examined for SBS with a universal testing machine after thermocycling (1,000 cycles of 5‒55°C). Data were analyzed with Shapiro-Wilk, one-way ANOVA, and Bonferroni tests. The statistical significance level was set at 0.05. The mean SBS was significantly different between all the groups (P < 0.001) except for Groups 2 and 5 (P = 1.00) and Groups 2 and 6 (P = 1.00). Group 4 had the highest mean of SBS. The bonding surface design significantly influenced the SBS of orthodontic attachments. The concentric circles with 32 cuts had higher bond strength than other designs and can be suggested as a new bonding surface design for orthodontic attachments.

Resin Loaded with Nanoparticles and Remineralizing Agents on the Bond Integrity and Microleakage of Tooth Color Restoration Bonded to the Bleached Enamel Surface

Aims: Assessment of remineralizing agent-modified resin adhesives i.e., Nanoparticles of amorphous calcium phosphate (NACP), Casein phosphopeptide-amorphous calcium phosphate (CPP- ACP), and Sodium Fluoride (NaF) on the shear bond strength (SBS) and microleakage of tooth color restoration bonded to the bleached enamel. Materials and Methods: Eighty premolar buccal enamel surfaces were bleached using a 10% carbamide peroxide gel. After 2 weeks samples were etched and then randomly allocated into four groups (n = 20) Group 1: No remineralizating agent + ER, Group 2: NaF + ER, Group 3: CPP-ACP + ER, and Group 4: NACP + ER. Composite restoration was performed followed by immersion in distilled water. Microleakage, SBS, and failure mode assessment were achieved. The mean and standard deviation (SD) of SBS and marginal sealing were compared using the Tukey post hoc test and One-way ANOVA. Results: Group 1 samples displayed the maximum value of marginal leakage. However, Group 4 samples exhibited the minimum scores of microleakage. Regarding SBS, Group 4 unveiled the highest outcomes of bond integrity. Whereas, Group 1 presented the lowest value of SBS. Conclusion: NACP-modified resin adhesives proved to be a better and safer alternative in improving the bond strength and microleakage scores of tooth color restorative material to bleached enamel.

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.

Effect of a Desensitizing Agent on Shear Bond Strength of Ceramic Bracket on Previously Bleached Teeth

This study aims to analyze the effect of desensitizing agents on the shear bond strength (SBS) of ceramic brackets after in-office bleaching procedures. Twenty-seven extracted premolars were equally divided into three groups (n = 9). Group 1 served as the control; bleaching was performed with 37% hydrogen peroxide. In group 2, bleaching and the application of a fluoride-containing desensitizing agent (CPP-ACFP) were performed. In group 3, bleaching and the application of a non-fluoride-containing desensitizing agent (CPP-ACP) were performed. Ceramic brackets were bonded with composite resin. SBS was tested using a universal testing machine. The site of bonding failure was measured using the adhesive remnant index (ARI) score. There was a statistically significant difference in mean SBS values (p &lt; 0.05). Group 1 showed the lowest SBS value (6.32 ± 4.83 MPa), which differed significantly with groups 2 and 3 (p &lt; 0.05). There was no significant difference between group 2 (15.36 ± 4.67 MPa) and group 3 (12.19 ± 6.81 MPa) (p &gt; 0.05). The ARI score did not show a significant difference. The conclusion is that the application of fluoride-containing and non-fluoride desensitizing agents increases the shear bond strength of ceramic brackets on bleached teeth with composite resin cementation. The application of both desensitizing agents had no impact on the results of the ARI score, with the highest ARI score in each group being 4, indicating that less than 10% of the adhesive substance remains on the enamel.

Evaluation of Different Priming Agents with Conventional and Bioactive Self-Adhesive Resin Cements on Shear Bond Strength to Zirconia

The aim of this study was to evaluate the effect of different priming agents on the shear bond strength (SBS) of conventional and bioactive self-adhesive resin cements to zirconia. One hundred and twenty zirconia discs were randomly divided into four main groups according to the priming agents used (n = 30): no priming agent (control), zirconia primer (Z-PRIME Plus), universal adhesive (All-Bond Universal), and universal ceramic primer (Monobond N). Then, each group was subdivided into three subgroups according to the type of self-adhesive resin cement used: TheraCem, Activa BioActive, and RelyX U200 Automix (n = 10). All specimens were subjected to thermocycling. The mean SBS data were analyzed using One-Way ANOVA, followed by multiple comparison Bonferroni test. Without the application of priming agents (control), most of the specimens failed during thermocycling. The priming agent, cement type, and their interaction had a significant effect on the SBS to zirconia (p &lt; 0.001). Only the type of priming agent showed a significant effect on the mode of failure (p &lt; 0.001), resulting in mainly mixed failure with Monobond N and adhesive failure with other primers. Regardless of the type of primer, Bioactive resin cements did not improve the SBS to zirconia compared to conventional cements.

Analysis of the effect of thermocycling on bonding cements to zirconia

ObjectiveThe aim of this study was to evaluate the effect of thermocycling on shear bond strength (SBS) of several resin cement materials to different types of zirconia dental ceramics. Materials and Methods120 square shaped disc specimens were fabricated using two types of zirconia blocks (Sagemax and Sirona). Each zirconia group was divided into three sub-groups based on the resin cement bonded to the specimens. Three different self-adhesive resin cements were used (Calibra, Breeze and RelyX). The specimens were further grouped into experimental and control groups (n = 10). The experimental specimens were exposed to a thermo-cycling protocol of 1500 cycles in water bath at 5c and 55c. Specimens were then stored at 37c for 24 h then all specimens underwent SBS test with an Instron machine. Mode of failure was inspected visually and microscopically. Data were statistically analyzed using multivariate analysis of variance followed by one-way analysis of variance, Tukey’s multiple comparison test, student’s t-test for independent samples were used to compare the mean values of SBS in relation to the categorical study variables. ResultsThe mean SBS values of experimental groups were significantly lower than control groups for all the 6 combinations of Zirconia and cement types (p < 0.0001). The higher mean difference (14.29 MPa) was observed in the combination of Sagemax and Rely-X. Rely-X displayed the highest SBS among all the cements while no significant difference was found in mean SBS values of Calibra and Breez cements in all groups. The mean SBS values of Sagemax zirconia were significantly higher than the Sirona with all three types of cements (p < 0.0001) within control groups. Microscopic and visual analysis demonstrated a majority of adhesive mode of failure. ConclusionThermocycling significantly reduced the SBS between the zirconia materials and self-adhesive resin cements tested. The amount of reduction varies according to cement and zirconia types.

Evaluation of the Effect of Two Surface Treatment Methods on Shear Bond Strength between Porcelain Veneer and Two Different Zirconia Blocks

Introduction: The aim of the study was to test the effect of two surface treatment methods on shear bond strength between a porcelain veneer and two different zirconia blocks. Materials and Methods: Sixty disk-shaped zirconia samples (30 samples of Novi brand and 30 samples of Rainbow brand) were used (diameter of 10 mm and thickness of 4 mm). Based on surface treatment, the samples were randomly divided into 3 groups: control, air-particle abrasion, and Zircos-E Etching Solution. Using the metal mold, the porcelain was veneered on the zirconia surface and then fired. Then, all samples were subjected to shear bond strength testing using a universal testing machine at a speed of 1 mm/min until breaking. Results: There was a statistically significant difference between the mean variable shear bond strength of the control group and two other groups, so the shear bond strength in the control group was less than in both groups. And there was no statistically significant difference between the mean variable of shear bond strength in the two groups of “airborne particle abrasion” and “Etching”. There was a statistically significant difference between the mean shear bond strength of the two types of zirconia samples and this amount was lower in Novi than in Rainbow. There was also no interaction between the type of surface preparation and the type of zirconia. Conclusion: It can be concluded that surface preparation with air particle abrasion and etching increases the shear bond strength of zirconia to porcelain veneer and the shear bond strength of zirconia and porcelain veneer is affected by the type of zirconia.

Repair Bond Strength of Two Shadeless Resin Composites Bonded to Various CAD-CAM Substrates with Different Surface Treatments

This study compared the repair bond strength values of two single-shade composite resins bonded to different computer-aided design and computer-aided manufacturing (CAD-CAM) substrates with different surface treatments. A total of 80 slice-shaped specimens were fabricated using two CAD-CAM materials: Lava Ultimate and VitaEnamic. The substrates were thermocycled and then, based on the surface treatment, each substrate material was subdivided into four groups: the air abrasion group (APA), the hydrofluoric-acid-etched group (HF) and two silicon carbide ground groups (SiCr). All of the groups received silane followed by Single Bond Universal Adhesive application prior to being repaired with a resin composite of a smaller disc shape. All the specimens were thermocycled prior to shear bond strength testing and subsequent failure analyses. Statistical analyses were conducted, and the level of statistical significance was set at 0.05. A comparison of the mean values showed a highly statistically significant difference among the eight groups. The highest value of mean shear bond strength was associated with Lava Ultimate substrates repaired using the Charisma Diamond ONE composite after APA surface treatment (36.7 ± 1.99). Meanwhile, the lowest value was recorded for the Vita Enamic group repaired using the OMNICHROMA composite after SiCr surface treatment (17.8 ± 1.6). The failure analysis revealed that cohesive failure in the substrate was the most predominant. Within the limitations of this study, Charisma Diamond ONE showed better bond strength values compared to Omnichroma. Meanwhile, APA is recommended for improved bond strength in repairs of Lava Ultimate restorations.

Evaluation of the Effect of Different Antioxidants on Resin Bond Strength to Enamel after Bleaching: An In Vitro Study.

To compare and evaluate the efficacy of 10% sodium ascorbate (SA) solution, 10% alpha-lipoic acid (ALA) solution, 10% propolis solutions (PLS), and 10% pomegranate peel extract (PPE) solution on the shear bond strength (SBS) between composite resin and bleached enamel after 60 minutes. Ninety extracted teeth were divided into 6 subgroups (n = 15) based on the antioxidant applied: Group I: Bleaching + application of 10% SA solution for 60 minutes. Group II: Bleaching + application of 10% ALA solution for 60 minutes. Group II: Bleaching + application of 10% PLS for 60 minutes. Group IV: Bleaching + application of 10% PPE solution for 60 min. Group V: Positive control (PC) bleaching without antioxidant application. Group VI: Negative control (NC) specimen neither subjected to bleaching nor application of an antioxidant solution. About 35% hydrogen peroxide (HP) was used for bleaching the labial surfaces in the groups considered. Labial surfaces were then bonded with composite using a customized cylindrical mold followed by storage in distilled water for 24 hours and shear bond strength was tested using universal testing machine. The mean shear bond strength values for groups I, II, III, IV, V, and VI are 5.04, 2.29, 5.02, 4.07, 1.42, and 9.08 respectively. The peak shear bond strength value is obtained for the negative control group; whereas the lowest mean SBS value is obtained for the positive control group. All herbal extracts used in the present study have demonstrated a reversal of reduced SBS between resin composite and bleached enamel surface. The reduction in bond strength of adhesive restorations was conventionally overcome by delaying the bonding procedure for a specified period resulting in prolonged treatment duration and multiple appointments. Sodium ascorbate is most commonly used but it is postulated to form a porous scaffold capable of harboring bacteria. Herbal antioxidants are gaining popularity in this regard as they are naturally derived, effective and affordable phytochemicals in addition to being viable alternatives against drug-resistant strains of microorganisms.

Shear bond strength of orthodontic brackets to specimens fabricated from temporary restorative materials by 3D-printing, CAD/CAM technology, and the conventional technique after surface treatment by sandblasting and laser

This study assessed the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets to specimens fabricated from polymethyl methacrylate (PMMA) temporary restorative material by 3D-printing, computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and the conventional technique, after surface treatment by sandblasting and laser. In this in vitro study, 60 disc-shaped specimens with 8mm diameter and 1mm height were fabricated from PMMA temporary restorative material by 3D-printing, CAD/CAM, and the conventional technique. In each group (n=20), half of the specimens were sandblasted while the other half underwent Er,Cr:YSGG laser irradiation. Brackets were bonded to the specimens and underwent thermocycling followed by SBS testing. Data were analysed by one-way ANOVA, independent t-test, and LSD test (alpha=0.05). A significant difference existed among the three fabrication methods in SBS in both laser (P<0.001) and sandblasting (P<0.001) surface treatment groups. In laser group, the mean SBS of CAD/CAM (P=0.000) and conventional (P=0.000) groups was significantly lower than that of 3D-printing group. In sandblasting group, the SBS of CAD/CAM group was significantly lower than 3D-printing (P=0.000) and conventional (P=0.000) groups. The mean SBS of laser-treated specimens was significantly higher than sandblasted specimens in 3D-printing group (P=0.000), and significantly lower than sandblasted specimens in the conventional group (P=0.000). A significantly higher SBS was obtained by laser treatment compared with sandblasting irrespective of the fabrication method (P=0.000). The highest SBS of SS orthodontic brackets to temporary restorative material was recorded for 3D-printed specimens treated by Er,Cr:YSGG laser irradiation.

An In vitro Assessment of the Shear Bond Strength of Two Different Pit and Fissure Sealants in Primary Teeth.

The current research had an aim to evaluate the shear bond strength of two different pit and fissure sealants in deciduous teeth. Forty deciduous teeth were part of this research. Inclusion criteria were teeth having an unbroken occlusal surface, whereas samples having developmental defects/afflicted with caries were subjected to exclusion from this research. Each specimen tooth was assigned at random to one of the two groups constituting 20 specimens each by means of a computer-generated randomization with two alphabets (A, B). Group 1: Conventional sealant, Group 2: Self-adhering flowable sealant. Following sealant coating, a shear load was placed via a universal testing apparatus in a manner parallel to the bonded edge at a speed of 0.5 millimeter/minute till the occurrence of a breakdown. Bond strength was subsequently measured in Mega Pascals (MPa). 13.86 ± 0.23 was the mean shear bond strength of self-adhering flowable sealant versus 11.48 ± 0.52 Mpa of conventional sealants. Statistically significant differences amid both groups were noted. The current research arrived at a conclusion that self-adhering flowable sealants exhibited superior shear bond strength in comparison to conventional sealants.

Effect of surface treatment on the repair bond strength of OMNICHROMA and Charisma Diamond ONE resin composites bonded to variable substrates

ObjectivesTo compare repair bond strength of OMNICHROMA and Charisma Diamond ONE resin composites bonded to variable composite substrates. Also, to evaluate the influence of different surface treatments on repair bond strength. MethodsA total of 80-disc shaped specimens was fabricated using two resin based composite materials; IPS Empress Direct Enamel and OptiShade (n = 40). Substrate discs were thermocycle 5000 cycles then each substrate material was subdivided based on the surface treatment into two groups; air particle abrasion (APA) and silicon carbide grinding (SiCr) both groups followed by phosphoric acid etching. All groups received a single bond universal adhesive application prior to repairing with composite, in a smaller disc shape. All specimens were thermocycled for 10,000 cycles prior to shear bond strength testing and subsequent failure analysis. Statistical analyses were conducted and the level of statistical significance was set at 0.05. ResultsThe comparison of mean values (considering the combination of the two types of substrates, surface treatments and repairing materials) showed a highly statistically significant difference in the shear bond strength among the eight study groups (p < 0.0001). The highest value of mean shear bond strength was associated with OptiShade substrates repaired by Diamond ONE (38.6 ± 2.4). Meanwhile, the lowest value was recorded for the SiCr treated OptiShade group repaired by Diamond ONE (13.6 ± 2.3). The failure analysis revealed that cohesive mode of failure was the most predominant. ConclusionOmnichroma showed higher repair bond strength values with SiCr surface treatment. Meanwhile, Charisma Diamond ONE had better bond strength with APA. Surface pretreatment had a significant impact on the repair bond strength where APA groups had significantly higher values compared to SiCr groups. Clinical Significance: Within the limitation of the present study; APA is recommended as surface pretreatment for improved bond strength in restorative composite repairs.

Comparative Evaluation Of The Shear Bond Strength Of Two Different Orthodontic Bonding Agents On Artificial Crown Surfaces: An Invitro Study

INTRODUCTION: Bonding of buccal tubes to the tooth is an essential procedure in orthodontic treatment. With the increase in the number of adult patients seeking fixed orthodontic treatment, there is a need to find a more reliable procedure to bond the artificial crown surface. Successful orthodontic treatment requires sufficiently high and durable bond between buccal tubes and ceramic/zirconia surfaces. There is a need for a bonding agent which can provide maximum bond strength to all surfaces. This study aimed to assess and compare the shear bond strength and adhesive remnants of orthodontic buccal tubes to natural teeth, ceramic crowns and zirconia crowns using two different bonding systems. METHODS: In this in vitro study, 60 extracted human molar teeth were randomly assigned to three groups (n=20) and then divided into two subgroups(n=10). Bonding of buccal tubes to enamel, ceramic and zirconia surfaces was done using Assure plus universal bonding resin and Enhance LC. The shear bond strength of buccal tubes to the enamel, ceramic and zirconia surfaces were determined by universal testing machine. The SBSs and ARI scores were statistically analysed with and Kruskal Wallis test. RESULTS: The mean shear bond strength of buccal tubes to enamel, ceramic and zirconia surfaces bonded with Assure plus and Enhance LC was highest for enamel followed by zirconia surfaces respectively. Non-parametric Kruskal-Walli’s test found significant differences regarding the shear bond strength and adhesive remnant index (ARI). CONCLUSION: Bonding of buccal tubes to enamel, zirconia, and ceramic surfaces with Assure universal bonding resin and Enhance LC provided adequate bond strength. Thus, it may be used for bonding of orthodontic buccal tubes to the artificial crown surfaces in the clinical setting.

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.

Evaluation of the effects of thermal changes on the bond strength between zirconia framework and veneering ceramic during the firing process.

The aim of this in-vitro study was to evaluate the effect of thermal changes to shear bond strength during the firing process of veneering porcelain on a zirconia framework. Single yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) framework ceramic (Kavo Dental GmbH) and three different types of veneering ceramics (IPS e.max Ceram, Vita VM9, and GC Initial Zr-FS) were used. One-hundred-twenty standard disc-shaped samples were prepared from zirconia blocks by using a CAD/CAM system (Kavo Everest). Four different cooling processes (maximum, 25°C/min, 50°C/min and 75°C/min) were applied to the veneering ceramics and the shear bond strength (SBS) test was performed. Ceramic surfaces were investigated by using scanning electron microscopeic (SEM). The possible occurrence of a t-m transformation of zirconia was evaluated by X-Ray Diffraction (XRD). Two-way analysis of variance, Bonferroni correction and paired comparisons were used for statistical analysis. The main effects of veneering ceramics on shear bond strength were found to be significant (p=0.042). The mean shear bond strength values differ according to the cooling process (p<0.001). The monoclinic phase ratio increased in groups with fast cooling process. The thermal changes during the firing process of veneering porcelain on a zirconia framework influenced the shear bond strength of the all-ceramic bilayered system. A slow cooling process provided higher strength for bilayer ceramic samples.