Bond Strength Of Composite Research Articles

Comparative Evaluation of Application of Universal Bonding on the Microtensile Bond Strength of Light Cure and Dual Cure Composites Bonded to Dentin.

Objectives: There is limited knowledge on the efficacy of universal adhesives when used in different etching modes. The aim of this study was to evaluate the microtensile bond strength (µTBS) to dentin using universal adhesives with light-cure and dual-cure composites. Materials and Methods: In this in vitro experimental study, the occlusal third of 60 caries-free human molars were removed and the exposed surfaces were treated and allocated to 10 groups (N=6). Two different bonding agents (Single Bond Universal, G-Premio) were used to bond 2 different composite resins (Z250 light-cure and CoreFlo DC dual-cure) to dentin, using etch-and-rinse (E&R) and self-etch (SE) modes. Single Bond 2 was applied in E&R mode on wet dentin to serve as control. The specimens were sectioned into 1×1 mm2 sticks with a precision saw. A microtensile testing machine was used to measure the µTBS of the specimens with a crosshead speed of 0.5 mm/min. Data were analyzed using three-way ANOVA and Bonferroni post-hoc test (α=0.05). Results: The Single Bond Universal group in SE mode with light-cure composite yielded the highest (39.24MPa), and the G-Premio SE group with dual-cure composite produced the lowest (13.65MPa) mean µTBS (P<0.05). The dominant failure mode was adhesive, in all groups. Conclusion: The bonding agent had a significant effect on µTBS of composite to dentin, but different composites and different etching modes were not significantly different in this respect.

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.

Evaluation of antioxidant application on bond strength of composite resins to bleached enamel

Abstract Aim: This study aims to assess and evaluate the application of 10% sodium ascorbate, 5% green tea extract, 5% pomegranate peel extract, and 5% grape seed extract on shear bond strength of composite to bleached enamel. Materials and Methods: Sixty extracted human maxillary central incisors were randomly divided into seven groups. The enamel surface of these specimens was bleached with hydrogen peroxide (35%), except group VII (control group). Postbleaching, the specimens of group II were placed in artificial saliva for 2 weeks before restoration and the specimens of groups III and IV and groups V and VI underwent antioxidant application; 10% sodium ascorbate, 5% green tea extract, 5% pomegranate peel extract, 5% grape seed extract, respectively, for 10 min, followed by composite resin restoration, respectively. The specimens of group I were restored with composite resin immediately after bleaching. The specimens’ shear bond strength was tested using universal testing equipment. The data obtained were statistically analyzed using a one-way analysis of variance and the Tukey post hoc test. Results: There was no statistically significant difference in the effects of various antioxidants on the shear bond strength of bleached enamel. Conclusion: Within the constraints of the study, it was concluded that the application of antioxidants efficiently recovered the bond strength of bleached enamel. The application of 5% grape seed extract treatment demonstrated better bond strength among the antioxidants tested. Clinical Significance: Antioxidants can be used immediately following bleaching to restore resin composite bond strength without the requirement of delay in the treatment to reduce the nascent oxygen species in bleached teeth.

Comparison of Repair Bond Strength of Bulk-fill and Conventional Composites With Different Bonding Systems

Background: One of the advantages of resin composites as a restorative material is their repairability. The purpose of the current study was to compare the repair bond strength of conventional and bulk-fill composites with different bonding systems. Methods: In this in vitro study, sixty cylindrical specimens of materials were prepared according to the six groups under study (two types of conventional Gradia Direct and N-Ceram Bulk-Fill Tetric composites and three bonding systems: Single Bond Universal and Clearfil SE Bond and Single Bond 2). The samples were divided into 6 groups of 10 Single Bond/Gradia Direct composite (G1), Single Bond/Tetric N-Ceram bulk-fill composite (G2), Clearfil SE bond/Gradia Direct (G3), Clearfil SE Bond/Tetric N-Ceram bulk-fill composite (G4), single bond universal/Gradia Direct composite (G5), and Single Bond Universal/Tetric N-Ceram bulk-fill composite (G6). Repair bond strength in each group was measured using the Universal Testing Machine (Hounsfield). All data were analyzed by SPSS 21 using ANOVA, Student’s t-test, and chi-square statistical tests (P&lt;0.05). Results: The highest and lowest bond strength (15.81±2.44 and 14.02±1.57, respectively) belonged to the Clearfil SE Bond-Tetric N-Ceram and Single Bond (Etch &amp; Rinse)-Gradia Direct groups, respectively. The ANOVA test results demonstrated no significant difference in the bonding strengths of the study groups (P=0.537). Conclusions: Bulk-fill composite Tetric N-Ceram, apart from the bonding system, had higher repair bond strength compared to the conventional Gradia Direct composite. It seems that self-etch bonding systems (Clearfil SE Bond and Single Bond Universal) have had more bond strength than etch and rinse bonding (Single Bond 2 bonds).

Effect of Different Decontamination Agents on The Bond Strength of CAD/CAM Blocks and Repair Composite Materials

The purpose of this study was to examine the effect of different decontamination agents on the bond strength of saliva-contaminated CAD/CAM blocks and repair composite materials. Two hunderd eighty 3-mm-thick specimens were prepared from four different CAD/CAM materials: Katana Zirconia UTML disc, IPS e.max CAD block, Shofu block, and Vita Enamic block. Each material was divided into seven different subgroups (N=70). Group 1 had a clean surface. The other groups were comprised of the samples, which were contaminated with human saliva: group 2: negative control (non-cleaned); group 3: cleaned with water spray; group 4: cleaned with 70% ethanol; group 5: cleaned with Ivoclean; group 6: cleaned with Katana Cleaner; and group 7: cleaned with phosphoric acid. After the decontamination protocols, the resin composite cylinders were bonded to the CAD/CAM surfaces with a thin layer of dual-cured resin cement. The samples were stored for 24 hours at 37°C in distilled water. Then, they were subjected to a shear bond strength test (SBS). The values were recorded, and fracture types were evaluated using a microscope. Data were analyzed using two-way ANOVA and Tukey’s post-hoc test. Generally, all decontaminating agents improved the SBS of composites to Katana Zirconia UTML, IPS e.max, and Vita Enamic materials (p&lt;0.05). However, for Shofu materials, group 6 samples exhibited significantly higher bond strength values as compared with group 2 samples (p=0.026). The highest SBS values were seen in the phosphoric acid-treated group in Katana zirconia materials (26.45 ± 9.38 MPa), whereas the lowest values were seen in group 2 samples in Shofu materials (13.17 ± 3.40 MPa). Each decontaminant agent improved the bond strength of composites to the contaminated CAD/CAM materials. If saliva is not cleaned before adhesive procedure, SBS values may decrease. All decontamination agents can be used safely on zirconia, lithium-disilicate glass-ceramic, hybrid ceramic, and polymer-infiltrated ceramic surfaces.

Repair bond strength of bulk-fill composites: influence of different primers and direction of debonding stress

Background The purpose of this in vitro study was to evaluate the effect of different adhesion primers on the repair bond strength of bulk-fill resin composite and short-term hydrolytic stability of the repair interface before and after accelerated aging. In addition, direction of debonding stress was examined. Materials and methods Bulk-fill substrates were aged in water for 14 days at 37 °C. Smooth resin composite surfaces were prepared for the substrates with a superfine grinding paper (FEPA #500, #1200, #2000). Test specimens were produced by attaching bulk-fill composite to the substrate surfaces, using three different primer/bonding systems. Specimens were aged 24 h at 37 °C in water, or thermal cycled (5–55 °C/5,000 cycles). Subsequently, shear bond strength and micro-tensile bond strength were evaluated. In total there were 60 specimens for the shear bond strength and 60 specimens for the micro-tensile bond strength measurements (30 stored in water 24 h, 30 thermal cycled, n = 10 in each primer/bonding mode). Results The mean shear bond strength was 9.1–13.1 MPa after 24 h water storage and 6.9–10.7 MPa after thermal cycling. The mean micro-tensile bond strength was 28.7–45.8 MPa after 24 h water storage and 22.7–37.9 MPa after thermal cycling. Conclusion The Ceramic primer (silane containing) seems to perform better than the three-step etch and rinse adhesive or the Composite primer. Shear-type stress had an adverse effect on the repair bond strength of bulk-fill resin composites.

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.

A laboratory investigation on the effect of biguanide- and pyridine-derived antiseptics on the adhesion of resin composites to dentin.

Optimal bonding of adhesive restorations to dentin is crucial to prevent microleakage and enhance the survival of root-filled teeth. The aim of this study was to investigate the effect of chlorhexidine (CHX), alexidine (ALX) and octenidine dihydrochloride (OCT) on the bond strength of resin composites to coronal dentin. Human coronal dentin specimens were treated with 2% CHX, 0.1% ALX, 0.1% OCT or saline then restored with traditional or bulk-fill resin composites. The adhesion strength between the resin and dentin was measured using the microtensile bond strength and failure mode was determined using a stereomicroscope. Treatment with ALX and OCT resulted in significantly greater μTBS compared with CHX and saline, irrespective of the resin composite used. Alexidine treatment predominantly resulted in mixed failure, while adhesive failures were frequently observed in CHX and saline-treated dentin. In conclusion, final irrigation with ALX or OCT improved the bonding of resin composites to dentin.

Effect of Dentin Surface Pretreatment With Chitosan Nanoparticles on Immediate and Prolonged Shear Bond Strength of Resin Composite: An in Vitro Study

Introduction: The objective of this study was to evaluate the impact of chitosan nanoparticles’ pretreatment of dentin surface on the macro shear bond strength of resin composite, both immediately and over an extended period. Methods: Thirty caries-free, unrestored human premolars were randomly assigned to six study groups. The dentin surface of the intervention groups underwent pretreatment with 0.2% chitosan and 0.05% NaF solutions for 1 minute. A standard etch-and-rinse adhesive procedure was performed for all the study groups. After 24 hours, half of the specimens underwent a macro shear bond strength test at a crosshead speed of 1 mm/min, whereas the other specimens underwent the same procedure after 300 thermal cycles between 5 and 55°C with a 30-second dwell time in the thermocycling device. Results: The study found that the type of dentin surface treatment agents did not significantly affect the shear bond strength (P = 0.52). However, there were statistically significant differences between immediate and prolonged shear bond strength in the chitosan (P &lt; 0.01) and the control groups (P = 0.005). On the other hand, there were no significant differences between the immediate and prolonged shear bond strength in the NaF group (P = 0.997). Conclusion: Dentin pretreatment with 0.2% chitosan solution did not significantly affect the shear bond strength of the etch-and-rinse adhesive system. Pretreatment with NaF maintained the shear bond strength of the adhesive to dentin after 300 thermal cycles.

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.

Phosphoric Acid Etch Partially Restores the Initial Bond Strength of Composite to Silver Diamine Fluoride-Treated Enamel Using Universal Adhesives.

Restoring bonding composite to silver diamine fluoride (SDF)-treated enamel is challenging. This study investigates if phosphoric acid etch restores composite bond strength to SDF-treated enamel using universal adhesives. Twenty-four recently extracted permanent teeth were randomly divided into 4 (2 experimental (SDF) and 2 control (CTR)) groups: SDF+Water: SDF (1 min) then water rinse (15 mL); CTR+Water: no treatment and water rinse (15 mL); SDF+Etch+Water: SDF (1 min), 35% phosphoric acid (40 s) then water rinse (15 mL); CTR+Etch+Water no treatment, 35% phosphoric acid (40 s) then water rinse (15 mL). The enamel surface in all the groups was bonded (All-Bond Universal) to 4-5 mm composite blocks (Z-250). Each sample was sectioned, and 6-8 beams (1 mm × 1 mm) were selected. The micro-tensile bond strength was measured by dividing the micro-tensile force peak by the adhesive surface area. Univariate ANOVA and Chi-square were used for between-group comparisons with p < 0.05. SDF+Water had significantly lower tensile strength compared to all the groups (p < 0.05). Although no difference was found in the tensile strength between the SDF+Etch+Water and the CTR+Etch+Water, the SDF+Etch+Water had significantly more adhesive failures compared to the CTR+Etch+Water (p = 0.047). While phosphoric acid etch seems to restore the initial composite bond strength to SDF-treated enamel, the long-term success of composite restorations bonded to SDF-treated enamel may need further investigation.

Comparison of Bond Strength of Bulkfill and Conventional Composites as Composite Repair Materials

Amaç: Bu in vitro çalışmanın amacı mikrohibrit, submikrohibrit ve bulkfill kompozitin kompozit tamir materyali olarak mikro gerilme bağlanma dayanımının ve kırılma yüzeylerindeki başarısızlık tipinin karşılaştırmalı olarak değerlendirilmesidir. Gereç ve Yöntem: Standart Teflon kalıplarda supranano kompozit rezinden (Estelite Sigma Quick) silindirik (4x4 mm) örnekler hazırlandı ve 3.000 termal döngüye maruz bırakıldı. Örneklerin bir yüzeyi abraze hale getirilerek mikrohibrit kompozit (Arabesk), submikrohibrit kompozit (Charisma Smart) ve bulkfill kompozit (Filtek Bulk-Fill Posterior) ile restore edilip 4x8 mm boyutlarında bloklar oluşturuldu. Kompozit bloklardan kesme cihazı ile her grup için 12 adet olmak üzere 1x1x8 mm3 ölçülerinde dikdörtgenler prizması şeklinde çubuklar elde edilerek mikro gerilim test cihazı ile bağlanma dayanımları test edildi. Ayrıca test sonrası her örneğin kopma yüzeyi stereo mikroskopta incelendi. Tamir bağlanma dayanımı verileri tek yönlü varyans analizi (ANOVA) ile karşılaştırıldı ve çoklu karşılaştırmalar Tukey HSD testi ile değerlendirildi. Bütün p&amp;lt;0.05 değerleri istatistiksel olarak anlamlı kabul edildi. Bulgular: Bulkfill kompozit grubu en yüksek ortalama mikro gerilim tamir bağlanma dayanımı değeri gösterirken en düşük ortalama değer mikrohibrit kompozit grubunda görüldü (p&amp;lt;0.05). Koheziv tip başarısızlık yüzdesi ise tamir bağlanma dayanımı değerlerine paralel şekilde tespit edildi (Bulkfill&amp;gt; Submikrohibrit&amp;gt;Mikrohibrit). Sonuç: Supranano kompozit rezinin tamirinde submikrohibrit ve mikrohibrit kompozite göre bulkfill kompozit ile daha iyi bir bağlanma sağlanabilir.

Impact of Irradiation on the Adhesive Performance of Resin-Based Dental Biomaterials: A Systematic Review of Laboratory Studies

Head and neck cancers are a significant global health burden, with radiation therapy being a frequently utilized treatment. The aim of this systematic review was to provide a critical appraisal of laboratory studies that assessed the effect of irradiation on the adhesive performance of resin-based biomaterials. The analysis included 23 laboratory studies obtained from five databases, with most studies using human enamel, dentin, or both, and bonding procedures involving the fabrication of direct restorations, standardized specimens, bonding of orthodontic brackets, and luting of endodontic fiber posts. The protocols used for irradiation varied, with most studies exposing specimens made from extracted teeth to irradiation using cabinet irradiators to simulate treatment of head and neck cancer. The findings indicate that irradiation reduces the bond strength of dental adhesives and resin-based composites on flat, ground enamel and dentin specimens, with different adhesives and timing of irradiation having a significant impact on adhesive performance. Irradiation also increased microleakage in most studies. The effect of irradiation on marginal adaptation of direct resin-based composite restorations was inconclusive. This systematic review indicates that irradiation has detrimental effects on the adhesive performance of resin-based biomaterials and highlights the need for further clinical and laboratory studies evaluating the performance of adhesive materials and approaches to improve it.

Comparative Evaluation of Effect of Different Antioxidants on Shear Bond Strength of Composites on Bleached Enamel: An In Vitro Study.

To evaluate the effect of antioxidants on the shear bond strength of composite resin to bleached enamel. A total of 120 extracted permanent anterior teeth were split into four major groups, one among them being a control group. Group I (bleaching + without antioxidant), group II (bleaching + 10% sodium ascorbate), group III (bleaching + 5% grape seed extract), and group IV (bleaching + 5% pine bark extract). All of the groups were bleached using a gel containing 35% carbamide peroxide, and then they were divided into two subgroups depending on when the bonding operation was to be completed-subgroup A was done in 24 hours, while subgroup B took 3 weeks. The universal testing machine was used to measure the shear bond strength. Subgroup IA showed poor shear bond strength than other groups, there was no statistically significant difference between subgroup IB, IIA, and IVA. Subgroup IIIA showed the highest shear bond strength than the remaining groups. Between subgroups IIA and IIB, IIIA and IIIB, and IVA and IVB there was no statistically significant difference. This shows that delaying the bonding procedure for 3 weeks shows similar shear bond strength when compared to groups that were immediately bonded after antioxidant applying groups. All the antioxidants' immediate application could reverse compromised bond strength. Among them, 5% grape seed extract shows the highest increase in shear bond strength. Maddula DC, Vasepalli M, Martha S, et al. Comparative Evaluation of Effect of Different Antioxidants on Shear Bond Strength of Composites on Bleached Enamel: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(1):87-92.

Evaluation and comparison of shear bond strength and adhesive remnant index score in brackets bonded with probiotics impregnated orthodontic adhesive and commercially available orthodontic adhesive - An in vitro study

Background: White spot lesions are one of the main drawbacks of fixed orthodontic mechanotherapy. Probiotic bacteria have been included in mouthwashes and lozenges to check the activity of S.mutans on surface enamel. Aim: Aim of the present study was to evaluate and compare shear bond strength and adhesive remnant index scores of orthodontic brackets bonded with probiotic impregnated (Lactobacillus rhamnous) orthodontic adhesive and conventional light cure orthodontic adhesive. Materials and methods: In this in-vitro study, two groups were tested in one group brackets were bonded to extracted maxillary premolars using probiotic impregnated composite and in the other with conventional light cure composite resin. Shear bond strength was assessed using universal testing machine. Adhesive remnant index scores were assessed on the same samples. Results: Shear bond strength of the new composite resin was significantly decreased when compared to conventional light cure composite (p=0.001). There was no significant difference in ARI scores (p=0.51) between the groups. Conclusions: The shear bond strength of the novel probiotic impregnated composite was significantly reduced. Though there was no significant variation in ARI scores when compared to control, avenues to improve the shear bond strength should be assessed.

Adhesive bond of Bioactive and bulk fill resin to disinfected caries affected dentin (lactobacillus specie) with laser and photodynamic therapy

AimsTo evaluate the antimicrobial effectiveness of cavity disinfectants chlorhexidine gluconate (CHX), Er, Cr, YSGG laser (ECL), and curcumin photosensitizer (CP) against Lactobacillus and shear bond strength (SBS) of Bioactive (BA) and bulk fill composite (BFC) restorative material bonded to carious affected dentin (CAD). Materials and MethodsSixty human mandibular molars scored 4 and 5 on the International Caries Detection and Assessment System (ICDAS) were included. After inoculating the specimens with lactobacillus specie all the samples were arbitrarily divided into three groups based on the disinfection regime used (n=20). Groups 1 and 2: CAD disinfection using ECL, Groups 3 and 4: CAD disinfection using CP, and Groups 5 and 6: CAD disinfection using CHX. After cavity sterilization, the survival rate was estimated and each group was further divided into two sub-groups based on the restorative material used. Groups 1, 3, and 5 (n = 10) were restored using BFC restorative material, and groups 2, 4, and 6 (n = 10) were restored using a conventional bulk-fill resin material. A universal testing machine (UTM) was used to determine the SBS and debonded surfaces were examined under a stereomicroscope to determine the modes of failure. Kruskal-Walis, ANOVA, and Post Hoc Tukey were applied to investigate the survival rate and bond strength values. ResultsECL group displayed the highest survival rate (0.73±0.13) of Lactobacillus. The least survival rate (0.17±0.09) was demonstrated by CP activated by PDT. Group 1 (ECL+ BA) treated specimens exhibited the maximum value of SBS (18.31 ± 0.22 MPa). However, group 3 (CP + BA) revealed the minimum values of bond strength (14.05 ± 1.02 MPa). The intergroup comparison revealed that group 1, group 2 (ECL+BFC) (18.11 ± 0.14 MPa), group 5 (CHX+ BA) (18.14 ± 0.36 MPa), and group 6 (CHX+BFC) (18.18 ± 0.35 MPa) displayed comparable outcomes of bond integrity (p>0.05). ConclusionCaries-affected dentin disinfected with Er, Cr: YSGG, and chlorhexidine improve bond scores of bioactive and conventional bulk-fill restorative material.

Use of nonhydrolyzed silane prior to the silane-containing universal adhesive application improves the repair bond strength of resin composite

ObjectiveTo compare the effect of hydrolyzed and nonhydrolyzed silanes prior to the silane-containing universal adhesive application on the repair bond strength between old and new resin composite. Material and methodsFifty-four blocks of nanohybrid resin composite (Z350 XT) were aged by water storage for six months. The aged specimen surfaces were wet-ground manually with 320-grit silicon carbide grinding paper and randomly assigned into six experimental groups according to surface treatment: silane-containing universal adhesive in the self-etch mode (Scotchbond Universal); nonhydrolyzed silane (Silane Coupling Agent) plus Scotchbond Universal; hydrolyzed silane (RelyX Ceramic Primer) plus Scotchbond Universal; self-etch adhesive system (Clearfil SE Bond); nonhydrolyzed silane plus Clearfil SE Bond; hydrolyzed silane plus Clearfil SE Bond. Blocks were repaired with the same composite. After 24 h of water storage, the blocks were sectioned and bonded sticks were submitted to microtensile bond strength test (μTBS). Two-way ANOVA and Tukey's tests were used to analyze the μTBS means. ResultsThe highest repair bond strength values were achieved when nonhydrolyzed silane was applied prior to the silane-containing universal adhesive system (p = 0.03). The previous silane application did not increase the repair bond strength when a two-step self-etch adhesive was used. Mixed/adhesive failures prevailed in all groups. ConclusionThe use of a nonhydrolyzed silane prior to the silane-containing universal adhesive in the self-etch mode application improves the repair bond strength of old and new resin composite.

Effects of different storage media on dentin moisture, microhardness, and bond strength of resin composite.

In in vitro studies, it is desirable that the storage solutions in which dental samples kept between extraction and experiment should prevent dehydration and have antimicrobial properties. However, it should be taken into consideration that these solutions may have some effects that directly change test results on physical and mechanical properties of laboratory samples. The aim of this in vitro study was to evaluate the effects of different storage media on dentin moisture, microhardness, and microshear bond strength of resin composite to dentin. Thirty non-carious human premolars were randomly divided into three groups: 1. 0.1% Thymol (T), 2. Distilled water (DW), 3. Dry storage (DS) (control) (n = 10). Dentin moisture was measured with a digital grain moisture meter. Dentin microhardness was measured with the Vickers test. The bond strength was measured with a microshear test. Analysis of variance (ANOVA) followed by the Bonferroni test was used for statistical evaluation (p = 0.05). Dentin moisture of the experimental groups was statistically higher than that of the control group (p < 0.05). In addition, the dentin moisture of group DW was significantly higher than that of group T (p < 0.05). The mean microshear bond strength of resin composite to dentin was higher in group DW than in group T and group DS (p < 0.05), while there was no statistical difference between group T and group DS. The microhardness values of all groups were statistically similar. Storage solutions used for disinfection and to prevent dehydration may have negative effects on dentin moisture and bond strength.

Influence of three different types of desensitizing agents on bond strength of etch-and-rinse and self-etch adhesive system on dentin: An in vitro study.

To determine the effect of three different dentin hypersensitivity treatment procedures on the microtensile bond strength of etch and rinse and self-etch adhesive system. Eighty extracted intact human permanent lower premolars were decoronated, and dentin was exposed on the buccal surface. The teeth were randomly assigned to two experimental groups of 40 teeth each: etch and rinse system or self-etch system. The 40 samples assigned were further randomly assigned to four desensitizing treatment subgroups: Control, Gluma, NovaMin, and GC tooth Mousse with 10 samples per subgroup. Desensitizing treatment was performed two times each day for 2 weeks respectively. The exposed dentin was subjected to etch and rinse or self-etch adhesive system bonding agent as per the group and restored using composite to 4-mm thickness. Samples were then subjected to universal testing machine for microtensile bond strength. The bond strength to the dentin obtained with etch and rinse adhesive system group where significantly higher (P < 0.05) when compared to self-etch adhesive system. However, there was no significant effect of the desensitizing agent on the microtensile bond strength in its own. Scanning electron microscope imaging reviled tubular occlusion in all specimens treated with desensitizer. The bond strength was majorly impacted by the type of adhesive system used. While the desensitizing agents used in the study had little or no adverse effect on the bond strength of composites to dentin surface.

Effect of shape of titanium dioxide nanofillers on the properties of dental composites

The main objective of the present study was to evaluate the effect of the morphology of titanium dioxide nanofillers on the flexural strength and shear bond strength of the dental composite. Spherical and rhombic-shaped nano titanium dioxide fillers were synthesized via solvothermal method and were characterized. Subsequently, these fillers were incorporated into a flowable composite (Filtek™ Z350 XT Flowable Restorative) at 0.5 wt.% and 1.5 wt.% and the prepared specimens were stored in water for 24 h. The specimens were then evaluated for flexural strength using a universal testing machine. Similarly, the shear bond strength of modified composites to the tooth was evaluated and bond failures were analyzed using stereomicroscope magnification. Incorporation of nanofillers significantly enhanced the flexural strength of flowable composite (p = 0.009) with a significant increase at 0.5wt.% of spherical (p = 0.015) and rhomboidal-shaped fillers (p = 0.010). However, no statistically significant difference in flexural strength was observed among the different shapes of nanofillers. The results of our study did not show a significant effect on the shear bond strength of the composites. Thus the reinforcing ability of titanium dioxide nanofillers on dental composite was confirmed in this study, although the effect of using nanofillers with different morphology was not significant.Graphical abstract