Highest Mean Shear Bond Strength Value Research Articles

Shear Bond Strength and Antibacterial Efficacy of Cinnamon and Titanium Dioxide Nanoparticles Incorporated Experimental Orthodontic Adhesive—An In Vitro Comparative Study

This in vitro study compared the shear bond strength (SBS) and antibacterial efficacy of an orthodontic adhesive containing either cinnamon or titanium dioxide (TiO2) nanoparticles (NPs). A total sample of 120 freshly extracted teeth was randomly divided into three groups, according to the type of NPs incorporated into adhesive for metallic orthodontic brackets’ bonding: group 1—conventional orthodontic adhesive (TXT) as a control; group 2—conventional orthodontic adhesive mixed with TiO2 NPs (TXT + TNP); and group 3—conventional orthodontic adhesive mixed with cinnamon NPs (TXT + CNP). The SBS and adhesive remnant index (ARI) scores were evaluated and compared between the groups. The antibacterial efficacy against Streptococcus mutans for all the groups was assessed via a disc agar diffusion test. Data comparisons among groups were performed by ANOVA followed by Bonferroni post hoc test. Antibacterial efficacy comparison between the experimental groups was performed via an independent t-test. The significance level for all the tests was set at p ≤ 0.05. The highest mean SBS values (10.11 ± 1.88 MPa) were in the TXT control group followed by TXT + TNP (9.40 ± 1.78 MPa), and the lowest SBS was in the TXT + CNP (8.99 ± 1.77 MPa) group. The mean SBS among the experimental groups was non-significant (p = 0.241). Antibacterial effects significantly increased (p ≤ 0.05) in both experimental groups. However, TXT + TNP revealed a significantly higher antibacterial effect (p = 0.021) than TXT + CNP. In conclusion, incorporating cinnamon or TiO2 NPs into an orthodontic adhesive improves its antibacterial effects without compromising the bond strength for clinical purposes.

Effect of combining different surface treatments on the surface characteristics of polyetheretherketone-based core materials and shear bond strength to a veneering composite resin

Statement of problemHigh-performance polyetheretherketone (PEEK) has been used in dentistry because of its excellent physical and chemical properties. However, its lack of translucency requires the use of a veneering composite resin for esthetic applications. Data on bonding a veneering composite resin to PEEK are still scarce. PurposeThe purpose of this in vitro study was to assess the effect of using and combining different surface treatments on the surface roughness and wettability of PEEK core materials and the shear bond strength (SBS) to a veneering composite resin. Material and methodsSixty square PEEK specimens were divided according to surface treatments into 6 groups: group N, no surface treatment; group A, airborne-particle abrasion; group L, ER:YAG laser treatment; group LA, laser treatment and airborne-particle abrasion; group P, plasma treatment; and group PA, plasma treatment and airborne-particle abrasion. Surface roughness (Ra) and wettability (contact angle θ) were measured followed by evaluation of the surface topography. After veneering, the SBS was measured. A 1-way analysis of variance (ANOVA) was used to assess all interactions with multiple pairwise comparisons (α=.05). ResultsThe highest mean Ra values were obtained for the combination treatment groups (LA 2.94 ±0.1 and PA 2.7 ±0.1 μm) (P<.001). While the laser (1.3 ±0.1 μm) and plasma treatment (1.4 ±0.1 μm) groups had the lowest Ra values, LA and PA had the highest wetting of PEEK surfaces (LA 6.9 ±0.7 and PA 4.9 ±0.2 degrees) (P<.001). The highest mean SBS values were demonstrated on PEEK surfaces with combination treatments (LA 22 ±1.3 and PA 21.2 ±0.8 MPa) (P<.001). ConclusionsCombining airborne-particle abrasion with laser or plasma treatments increased the surface roughness and wettability of PEEK surfaces favorably compared with applying each of the 3 treatments individually. The combinations enhanced the bond strength of PEEK to the veneering composite resin.

RETRACTED: Graphene oxide-modified dental adhesive for bonding orthodontic brackets

Recently, dental resin adhesives are being incorporated with several nanoparticles to improve their mechanical and biological features. This study aimed to synthesize and characterize silanized graphene oxide (SGO) nanoparticles and assess the spectral, microbiological, and mechanical analysis of SGO-modified adhesive bonded to orthodontic brackets. Graphene oxide, manufactured using Hummer's method, was silanized utilizing tetraethylorthosilicate to synthesize SGO nanoparticles. The adhesive's characterization along with their biological and physical characteristics were assessed using scanning electron microscopy and energy dispersive X-ray spectroscopy; its degree of conversion (DC), cytotoxicity, antibacterial effect, shear bond strength (SBS), and adhesive remnant index (ARI) were examined. Transbond XT (control adhesive) was modified by incorporating 0.25 wt% and 0.5 wt% SGO-modified adhesive, which served as the experimental groups. Sixty orthodontic brackets were bonded to tooth surfaces for each study group (n = 20). Five disks of control and experimental groups were prepared measuring 5 mm in diameter and 1 mm in height each. SGO nanoparticles were synthesized with 100–700 nm in size and 1–2 nm thickness. Among the experimental groups, the samples treated with 0.25 wt% SGO-modified adhesive showed the lowest mean DC score (38.46 ± 5.12), the highest mean SBS values (13.84 ± 2.55 MPa), and the least ARI (post-thermocycling) scores (1.33 ± 0.54). 0.25 wt% SGO-modified adhesive samples showed a greater relative biofilm viability against S. mutans than 0.5 wt% SGO-modified adhesive samples after 24 h and 30 days. 0.25 wt% SGO-modified adhesive group showed higher SBS, sufficient durability, greatest bactericidal and least cytotoxic effect than 0.5 wt% SGO-modified adhesive and Transbond XT.

The Effects of Amalgam Contamination and Different Surface Modifications on Dentin Shear Bond Strength When Using Different Adhesive Protocols.

PurposeTo evaluate the effect of amalgam contamination, different surface treatments, and adhesive protocols on dentin shear bond strength (SBS) to bulk-fill composite resin material.Materials and MethodsEighty teeth were fixed in molds, and the dentin was exposed and then polished. Sixty teeth were restored by amalgam and thermocycled to 10,000 cycles (5°C and 55°C, 30-second dwell time). The rest were restored with composite materials without amalgam predecessor. The samples were divided into G1 (with dentin pretreatment with 2% chlorhexidine gluconate), G2 (0.5 mm of dentin was removed), G3 (no surface modification), and G4 (samples were restored with bulk-fill composite). The bonded specimens were subdivided based on the adhesive protocol of the universal adhesive system used into etch-and-rinse and self-etch groups. Acid etching was done using 32% phosphoric acid. Composite resin was used for build-up using mold and glass. Specimens were cured and left for 24 h in distilled water at room temperature for polymerization reaction, underwent thermocycling for 5000 cycles, and were subjected to knife-edge shear bond testing. Descriptive statistics, independent t-tests, and one-way analysis of variance followed by pairwise comparisons were used to analyze the results.ResultsThe highest mean SBS values were found in the control group where acid etching was used (24.46±2.24 MPa), followed by self-etching in the same group (21.92±2.54 MPa). Lower SBS values were associated with the amalgam-contaminated group. The lowest values were found in the dentin refreshment group when the self-etching mode was used (13.59±1.73 MPa). Chlorhexidine treatment improved the mean SBS value compared with the no treatment or dentin refreshment groups for both adhesive protocols.ConclusionAmalgam contamination may affect SBS values. Acid etching improved SBS for non-contaminated dentin. Chlorhexidine improved SBS for amalgam-contaminated dentin as a surface treatment but had no significant effect.

Evaluation of the bond strengths of restorative materials to primary tooth dentin treated with different pulpotomy techniques.

The aim of this study was to investigate the changes of different pulpotomy techniques on the primary tooth dentin and to evaluate the effects of these pulpotomy methods on the shear bond strength of restorative materials to primary tooth dentin. Two hundred and forty dentin specimens were distributed randomly to the study groups as; control, ferric sulphate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma (APCP). After the application of pulpotomy methods, samples were again randomly divided to two restorative materials (glass hybrid and composite resin) (n=20) and shear bond strength (SBS) test was performed. Then, 12 new dentin specimens were prepared for all groups for surface analysis. Surface examination (n=12) and fracture analyses (n=240) were carried out with scanning electron microscope (SEM). Statistical significance range was accepted as α <.05 for all data. A statistically significant difference was obtained among all study groups for glass hybrid material as well as composite material (p <.05). While the highest mean SBS value was obtained with Nd:YAG laser (7.58 ± 0.60 MPa), the lowest value was observed with Biodentine® (6.70 ± 0.91 MPa; p=.001) for glass hybrid material. For composite material, the highest mean SBS value was calculated for Nd:YAG laser (13.79 ± 1.24 MPa), while the lowest value was obtained with ferric sulphate (10.17 ± 1.45 MPa; p=.001). Fracture modes were mainly adhesive and mixed type according to SEM analysis. Moreover, morphological changes were observed with SEM on the dentin surfaces of ferric sulphate, Biodentine® and Nd:YAG laser. Within the limitations of this study, Nd:YAG laser increased the shear bond strength values in groups of composite resin. RESEARCH HIGHLIGHTS: In this article, we report the results of the shear bonding strength test of two restorative materials (glass-hybrid vs. composite resin) to primary tooth dentin following the application of five different pulpotomy techniques (ferric sulfate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma) were reported. This article will contribute to the literature that there are considerably limited researches concerning the bond strength of glass hybrid to primary dentin and also atmospheric pressure cold plasma in pulpotomies. The SEM examination was performed in two stages in this study; the morphological changes in both treated dentin surfaces and the surfaces of the samples subjected to the shear bond strength test.

Effect of ageing media on shear bond strength of metal orthodontic brackets bonded with different adhesive systems (A comparative in-vitro study)

Background: The aim of this study was to evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) of different orthodontic adhesive systems after exposure to aging media (water storage and acid challenge). Materials and methods: Eighty human upper premolar teeth were extracted for orthodontic purposes and randomly divided into two groups (40 teeth each): the first group in which the bonded teeth were stored in distilled water for 30 days at 37°C, and the second group in which the bonded teeth were subjected to acid challenge. Each group was further subdivided into four subgroups (10 teeth each) according to the type of adhesive system that would be bonded to metal brackets: either non-fluoride releasing adhesive (NFRA), fluoride releasing adhesive (FRA), Fluoride releasing bond with self-etching primer (FRBSP), or powder and liquid orthodontic fluoride releasing adhesive (PLFRA). After 30 days of water storage and acid challenge ageing procedures, the SBS was determined using Instron testing machine with a crosshead speed of 1 mm/min. The ARI was assessed using a stereomicroscope with 10 X magnification. Result: The SBS testing revealed significant differences (p&lt; 0.05) among the four tested adhesive systems in water storage and acid challenge groups using ANOVA F-test. In both groups, the NFRA subgroup exhibited the highest mean SBS value, followed by FRASP, then FRA subgroups, while the PLFRA subgroup had the lowest value of mean SBS. The independent t-test showed non-significant differences in mean SBS values between water storage and acid challenge groups. In respect to the ARI analysis, the Chi-square test showed significant differences among the tested adhesive systems. Conclusion: The shear bond strength of the fluoride releasing adhesive system was less than that of the non-fluoride releasing adhesive system, but still above the clinically acceptable range.&#x0D;

Bond Strength of Metallic or Ceramic Orthodontic Brackets to Enamel, Acrylic, or Porcelain Surfaces.

Bonding strategies within different brackets and dental materials are still a challenge concerning adhesion and dental surface damage. This study compared the shear and tensile bond strength of orthodontic ceramic and metallic brackets to enamel, acrylic, and ceramic surfaces after thermal cycling. Dental surfaces were divided into three groups: enamel, ceramic, and acrylic. Each group received stainless-steel and ceramic brackets. After thermal cycling, specimens were randomly divided into two subgroups considering tensile (TBS) or shear bond strength (SBS) test. After the mechanical testing, scanning electron and optical microscopy were performed, and the adhesive remnant index (ARI) was determined. The two-way ANOVA full factorial design was used to compare TBS, SBS, and ARI on the surface and bracket type (α = 0.05). There were significant differences in TBS, SBS, and ARI values per surface (p < 0.001 and p = 0.009) and type of bracket (p = 0.025 and p = 0.001). The highest mean SBS values were recorded for a ceramic bracket bonded to an acrylic surface (8.4 ± 2.3 MPa). For TBS, a ceramic bracket bonded to acrylic showed the worst performance (5.2 ± 1.8 MPa) and the highest values were found on a metallic bracket bonded to enamel. The adhesion of metallic or ceramic brackets is enough for clinical practice although the damage of the enamel surface after debonding is irreversible and harmful for the aesthetic outcome of the teeth.

Shear Bond Strength of a Multi-Mode Adhesive to Bur-Cut and Er,Cr:YSGG Lased Dentin in Different Output Powers

Statement of the Problem: Universal or multi-mode adhesives are new adhesive systems that can be used in both etch-and-rinse (ER) and self-etch (SE) modes. Lesser technical sensitivity and dual use of these adhesives have made them popular among dentists. Studies are being conducted to analyze the advantages and disadvantages these adhesives in different conditions. Purpose: The aim of this study was to compare shear bond strength (SBS) of a multi-mode adhesive in different etching modes to Er,Cr:YSGG laser ablated and bur-cut dentin. Materials and Method: Buccal and lingual surfaces of 30 sound human molars, randomly divided to three groups, were prepared by bur and Er,Cr:YSGG (4 Watt and 5 Watt, 20 Hz, 96% water, 60% air, and 600-µm spot size) to reach a flat surface in superficial dentin. Each group was randomly divided into 2 subgroups (ER and SE), and then Scotchbond Universal adhesive was applied. Composite cylinders were attached to the surfaces and cured. Specimens were stored in 37 °C water for 24 hours and thermocycled (500 cycles) and were tested for SBS and failure modes were determined by stereomicroscope. Data was analyzed using SPSS19 and one- way ANOVA and Tukey’s post hoc tests and p< 0.05 was considered as significance level. Results: Bur-cut dentin with ER method had the highest mean SBS value (33.80 MPa). SBS in bur-cut and 4Watt laser in ER mode were significantly higher than SE mode (p= 0.002 and p= 0.000 respectively). Highest mean SBS value in lased dentin was achieve in 4 Watt ER mode. Conclusion:SBS of Scotchbond universal adhesive to dentine is highest in bur-cut and ER mode and in 4-Watt lased-dentin is higher than 5-Watt lased-dentin. Moreover, in 4-Watt lased-dentin, SBS of ER mode is more than SE mode.

Effect of self-etching ceramic primer on the bond strength of feldspathic porcelain repair

The purpose of this study was to evaluate the effect of a self-etching primer on the bond strength of feldspathic porcelain with composite resin. Forty-eight feldspathic porcelain specimens (13 mm × 13 mm × 2 mm) were sectioned from CAD/CAM blocks. Specimens were randomly divided into 4 groups (n = 12) as regards to surface treatment method; HF acid etching (HFE), Monobond Etch and Prime (MEP), sandblasting (SB), and MEP + SB. After silane application for group HFE and SB, an adhesive bond was used as a bonding agent in all groups. Composite resin cylinders were build up onto the specimens. Specimens were stored in distilled water, thermocycled 5–55 °C for 5500 cycles, and subjected to shear bond strength (SBS) test in a universal testing machine. Data were statistically analyzed by Kruskal-Wallis and Mann Whitney U test (α=.05). Type of failures was evaluated under optical microscopy and surfaces were examined by SEM at ×500 and ×2500 magnifications. There was a significant difference among groups. (p = .019) HF group had the highest mean SBS value (17.54 ± 2.98 MPa) which was significantly higher than other groups (p<.05). Followed by the MEP + SB group (14.68 ± 3.41 MPa), SB group (13.98 ± 3.34 MPa) and MEP group (12.75 ± 2.33 MPa). Nevertheless, the HFE group significantly has higher SBS value than other groups all of the tested surface treatment methods have reached the convenient bond strength values for repair. Although MEP showed clinically acceptable SBS values, further researches with another type of porcelains should be tested.

Bond strength of three different universal adhesives after different thermal cycling protocols

The purpose of this study was to examine the bond strength of three different universal adhesives on enamel after different aging periods. Ninety enamel specimens were prepared and randomly assigned into three groups according to different universal adhesive systems (n = 30): iBOND Universal (IB), G-Premio Bond (GP), Clearfil Universal Bond Quick (CU). All adhesives were applied at etch&rinse mode. A cylinder-shaped resin composite was placed on enamel surfaces and light cured. Then all specimens were stored in distilled water at 37 °C for 24 h and divided into 3 thermal cycling protocol groups (n = 10): No thermal cycling (NTC), 10,000 thermal cycles (10TC), 40,000 thermal cycles (40TC). Specimens were subjected to shear bond strength (SBS) test at a universal testing machine. Failure modes were determined and SEM analyses were performed for each failure mode. Data were analyzed using two-way ANOVA followed by Tukey HSD test. The highest SBS values were observed at NTC groups. The 40TC groups showed significantly lower SBS values than other groups (p < 0.05). The highest mean SBS values were obtained in IB at NTC group (p < 0.05). After 10TC, all universal adhesives exhibited similar SBS values (p > 0.05), however after 40TC, CU showed higher SBS than GP. The mean shear bond strength to enamel was significantly affected by thermal cycling (p < 0.05). The enamel bond durability of universal adhesives dractically decreased after 10,000 and 40,000 thermal cycling periods. The universal adhesives tested showed different SBS values at NTC and after 40TC.

Effect of Different Temporary Crown Materials and Surface Roughening Methods on the Shear Bond Strengths of Orthodontic Brackets

The aim of this study was to evaluate the effect of different temporary crown materials (TCMs) and surface roughening methods on the shear bond strength (SBS) of orthodontic brackets. TCMs are widely used during orthodontic treatment in teeth in need of prosthetic treatment, to prevent damage to the final restoration. However, there is no consensus considering the best method for roughening of the surface of TCMs. Five different TCMs [Dentalon Plus-(D), Basworth Trim II-(B), Voco Structure Premium-(V), 3M ESPE Protempt 4-(P), and Revotek LC-(R)] were used in this study. Different surface roughening methods (37% phosphoric acid, sandblasting, and Er:YAG laser) were employed in three subgroups (n=20). The SBS test was used to assess the durability of all groups. Scanning electron microscopy (SEM) analysis was performed on a representative specimen in each group. The highest mean SBS value was observed in group V, followed by groups D and P, regardless of the surface treatment. The lowest SBS values were observed in group B. The laser-irradiated groups had higher SBS values than the sandblasted and acid-etched groups. Furthermore, a significant difference in SBS values was observed between the laser-irradiated group V and all other groups (p<0.005). The effects of the chemical nature of TCMs on the SBS values appeared to be clinically negligible, whereas the type of surface treatments had a significant influence on bond strengths. Er:YAG laser irradiation caused a significant increase in bond strength between the TCMs and orthodontic brackets.