Papers by Keyword: Shear Bond Strength

Abstract: Indonesia is a country that has many types of freshwater fish, one of which is tilapia. The consumption of tilapia among the people of Indonesia is quite high. So that, it will produce a lot of fish scale waste. Fish scales can be used as a natural source of hydroxyapatite because they contain calcium. The aim of this study was to evaluate the effect of hydroxyapatite synthesized from tilapia fish scale (Oreochromis niloticus) on the shear bond strength of glass ionomer cement and resin modified glass ionomer cement to enamel layer. Hydroxyapatite was synthesized from tilapia fish scale (Oreochromis niloticus) by calcination method at 800°C. Sample was made from glass ionomer cement (GIC) and resin modified glass ionomer cement (RMGIC) combined with 2, 5 and 8%wt of hydroxyapatite, respectively. Sample was bonded to enamel layer of human premolar tooth. The shear bond strength of sample was tested by using Universal Testing Machine. The result showed that shear bond strength were increased for higher concentration of hydroxyapatite that added to glass ionomer cement or resin modified glass ionomer cement. The maximum of shear bond strength of GIC Group is 6,38 ± 0,05MPa after 8%wt hydroxyapatite addition. The maximum of shear bond strength of RMGIC Group is 6,59 ± 0,06 MPa after 8%wt hydroxyapatite addition. There were significance differences among all group tested (p <0.05). It can be concluded that hydroxyapatite synthesized from tylapia fish scale can increase the shear bond strength of glass ionomer cement and resin modified glass ionomer cement.

Abstract: The objective of this study was to compare shear bond strength (SBS) and adhesive remnant index (ARI) of domestically made orthodontic adhesives to a commercial orthodontic adhesive, Transbond XT (3M Unitek, USA). Three formulas of an in-house orthodontic adhesive were divided according to monomer ratio (BisGMA:TEGDMA) into group 1 (8:2), 2 (7:3), and 3 (6:4), respectively, with 60-70 weight % of filler amount and 0.5 % of photoinitiator (TPO). Eighty upper human premolars (20 of each group) were bonded with stainless-steel brackets with these experimental and control adhesives. All were cured by LED light-cured unit for 20 seconds. After polymerization for 24 hours, a universal testing machine was used to apply an occlusal shear force to the enamel/bracket interface at a speed of 0.5 mm/min. The ARI scores were evaluated for each debonded tooth. Mean SBS values were analyzed statistically using the One-way ANOVA and the Tukey’s test for multiple comparison. Chi-square test was used to determine significant difference in the ARI scores. The results showed that there was statistical difference in the mean SBS of 4 groups (P<.001). The SBS value of group 1, 2, 3, and control was 18.79 MPa, 18.58 MPa, 23.30 MPa, and 28.02 MPa, respectively. Chi-square comparison for the ARI indicated that there was significant difference (P=.012) between the groups. In conclusion, the experimental adhesive of group 3 yields the higher SBS than in group 1 and group 2. Although these adhesives provide a lower shear bond strength than Transbond XT, they were acceptable for clinical use. Most failures of Transbond XT were found between adhesive-bracket interface, whereas the three in-house experimental adhesives were found mixed failure patterns of ARI.

Abstract: The bonding ability of resin cement to metal alloys of conventional dental restorations is critical for the retention and long-term survival rate. Contaminated saliva during try-in process which is resistant to simple water rinsing could reduce bond strength. Surface treatment before cementation might have an important role in optimizing resin-metal bond strength. The purpose of this study was to study the effect of surface pretreatment on the shear bond strength of dental base metal alloys after saliva contamination using a self-adhesive resin cement. Forty dental wax patterns (7-mm diameter) were made and cast with dental base metal alloy (Argeloy N.P. (V)). Cast metal specimens were embedded in PVC tube using self-curing acrylic resin and then flattened with 600-grit silicon carbide paper. PVC tube holders were specifically designed for the shear bond strength test device. Forty resin composite specimens were prepared in plastic mold (diameter of 3 mm and depth of 3 mm). The resin composite specimens were treated with sandblasting. Fifty-μm aluminum oxide particle was blasted for 10 seconds from the distance of approximately 5 mm perpendicular to the bonding surface. Metal alloy specimens were immersed in artificial saliva for 1 minute and rinsed with water-spray for 15 seconds. The specimens were also air-dried for 15 seconds. Specimens were divided into four groups, which received one of the following surface treatments: (1) No surface treatment (Control), (2) 37% phosphoric acid, (3) 37% phosphoric acid and then rinsed with 70% ethyl alcohol, and (4) 70% ethyl alcohol. After rinsing and drying, the resin composite specimens were cemented with Panavia SA Cement (Kuraray Noritake Dental Inc., Okayama, Japan) at the center of metal alloy specimens followed by the manufacturer’s instruction. Before testing, the specimens were stored in distilled water at 37oC for 24 hours. For testing, specimens were dried and mounted to universal testing machine (EZ-S, Shimadzu Co., Kyoto, Japan) at the crosshead speed of 1 mm/minute. Failure loads was recorded in Newton (N) and then analyzed to Mega Pascal (MPa). The highest shear bond strength was observed for group 2 and 3. The failure mode in all the materials was adhesive failure which occurred at the resin-metal interface. Within the limitations of this study, phosphoric acid was effective in removing saliva contamination and enhancing bond strength at the resin-dental base metal interface.

Abstract: Objective: The purpose of this study was to compare shear bond strength (SBS) and adhesive remnant index (ARI) of three light-cured orthodontic adhesives.Methods: Sixty upper human premolars were randomly divided into three groups of 20 teeth each. Stainless steel brackets were bonded to the specimens with two different color-change adhesives (Grengloo and Green Glue) and a control (Transbond XT), according to manufacturer’s instructions. After bonding for 24 hours, a universal testing machine was used to apply an occlusal shear force directly to the enamel/bracket interface at a speed of 0.5 mm/min. The ARI scores were evaluated for each debonded tooth. Mean SBS values were analyzed statistically using the Welch robust analysis of variance and the Games-Howell post hoc statistic. Chi-square test was used to determine significant difference in the ARI scores.Results: There was statistical difference in the mean SBS of the three groups (P<.001). The lowest value was obtained from the Green glue (14.88 MPa), which significantly differed from the Grengloo (29.25 MPa) and the Transbond XT (28.03 MPa) group. Chi-square comparison for the ARI indicated that there was significant difference (P=.018) between the groups. Mixed failure patterns were observed for all materials.Conclusion: Although Green glue yielded lower SBS values than Grengloo and Transbond XT, it was sufficient for orthodontic and biting forces in clinical practice.

Abstract: The purpose of this study was to compare shear bond strength and to evaluate Adhesive Remnant Index (ARI) score among three chemically cured orthodontic adhesive resins, namely Unite (3M Unitek, USA), Rely-a-Bond (Reliance, USA) and Ortho-Force (China). Materials and methods: Ninety extracted human maxillary premolars were randomly divided into 3 groups (30 teeth/group). Upper premolar metal brackets (Ormco, USA) were boned by using the following adhesive systems: Unite, Rely-a-Bond and Ortho-Force. After 24 hours, shear bond strength was tested by using a Universal Testing Machine with a crosshead speed of 0.5 mm/min. After debonding, all teeth and brackets were examined under 10-times magnification and scored by using Image-Pro Plus 7.0 software program. Results: One-way ANOVA followed by post-hoc Tukey HSD multiple comparison test showed a statistically significant (P<0.05) difference among groups. Ortho-Force had the lowest shear bond strength (17.53±3.60 MPa) and demonstrated statistically significant difference (P<0.05) from the other groups. The difference between Unite (22.40±3.11 MPa) and Rely-a-Bond (20.67±2.70 MPa) was not statistically significant. The bond failure sites were categorized according to the ARI, and the Chi-square test showed significant differences in the ARI scores (P<0.05) among all sample groups. The ARI score of 3 was found to be the most prevalent in Ortho-force (73.33%), followed by Unite (66.67%), and Rely-a-Bond (0%). In Rely-a-Bond group, ARI score of 1 was the most prevalent (66.67%). Only Unite had no residual adhesive left on tooth surface after debonding (6.67%). Conclusions: Unite and Rely-a-Bond produced greater shear bond strength than Ortho-Force. According to ARI score, Unite and Ortho-Force had a high frequency of all the adhesive remained on the tooth surface but Rely-a-Bond had high frequency of less than half the adhesive remained on the tooth surface.

Abstract: The aim of the study was to examine the effect of surface treatment of titanium elements on the bond strength to zirconium dioxide. Forty cylindrical titanium discs (Tritan CpTi 1) were divided into four groups (n=10) that were subject to: grinding (Group A), grinding and acid-etching with 5% HF (Group B), sandblasting with 60μm alumina particles (Group C) and sandblasting with 60μm alumina particles and acid-etching with 5% HF (Group D). Prepared materials were bonded to cylindrical discs made of zirconium dioxide (Ceramill Zi) by composite cement (Panavia F 2.0). The specimens were tested for the shear bond strength. The load was applied to the moment of the bond failure. Than the debonded specimens were vertically sectioned and the fractographic analysis of interfacial fractures under SEM as well as the analysis of chemical composition of the obtained fractures using radiographic spectrum were performed. The results were subject to the statistical analysis by using the analysis of variance. The highest values of bond strength were obtained for specimens whose surface was sandblasted and abraded. Fractographic investigation and the analysis of chemical composition of the cross-sections of the interfacial fractures revealed that the fracture occurred at the titanium-resin cement interface. Air abrasion treatment considerably improves the titanium and composite cement bonding and should be recommended for cementation of prosthodontic restorations constructed on titanium implants.

Abstract: In this paper finite element model of steel dental bracket is generated along with bonding agent, enamel & stress analysis is carried out on the bracket for different loading conditions. Three dimensional finite element model developed are constrained with boundary condition that resembles to the reality. The Vonmisses stress is recorded for each loading conditions and compared with experimental results. The experimental work for 60 samples were carried out on Universal testing machine at material testing laboratory, Basaveshwar Engineering College, Bagalkot. It is found from FEM results that the shear bonding strength for different loadings from 60 N to 80 N varies from 7.276 N/mm² to 9.7N/mm², which are closer to experimental values with acceptable error. The study reveals that Finite Element Method can be used as a strong tool to analyze the dental bracket and study different parameters to improve its performance and to avoid time and cost required for experimentation.

Abstract: To evaluate bond strength of veneering ceramics to a graded zirconia core. Two zirconia core ceramics (Y-TZP and graded zirconia) were fabricated and veneered with IPS e.max Ceram. A metal ceramic system (IPS d.SIGN, Ivoclar Vivadent, Liechtenstein) was used as a control group for the two all-ceramic test groups (n=20). Shear bond strength test and microtensile bond strength test were conducted by a universal testing machine. Fracture surfaces were also evaluated to determine the failure modes. Additionally, one-way ANOVA and Tukey's HSD tests were used to analyze the data. The shear bond strength test and microtensile bond strength test showed the familiar results. Graded zirconia exhibited the highest bond strength value (SBS: 31.01±2.01 MPa, MTBS: 40.95±1.95 MPa), significantly higher than that of Y-TZP (SBS: 28.14±2.28 MPa, 37.99±2.83 MPa). No significant differences were found between the metal core group and the two zirconia core groups. All test groups demonstrated cohesive failure within the veneer, as well as adhesive failure between the core and the veneer. Glass infiltration to zirconia may affect bond strength between zirconia core and veneering ceramics. A graded zirconia glass structure exhibits a benign bond to a veneering ceramics which could be similar to that of a metal ceramic system.

Abstract: Steel-concrete joints are often provided with welded shear studs. However, stress concentrations are induced in the structure due to the welding. Moreover, a reduction in toughness and ductility of the steel and a decreased fatigue endurance of the construction is observed. In this paper the shear bond strength between steel and ultra-high performance concrete (UHPC) without mechanical shear connectors is evaluated through push-out tests. The test samples consist of two sandblasted steel plates with a thickness of 10 mm and a concrete core. The connection between steel and concrete is obtained by a 2-component epoxy resin. Test samples with a smooth adhesive layer are compared with those with an epoxy layer, which is applied with a toothed paddle and/or gritted with small aggregates. In this research, specimens prepared with river gravel, crushed stone, and steel grit are compared and also two different epoxy resins are used. During the tests, the ultimate shear force is recorded as well as the slip between steel and concrete. All test specimens exhibited a concrete-adhesive or concrete failure. Furthermore, test results show that the use of a more fluid epoxy resin improves the anchorage of the gritted aggregates in the adhesive layer, resulting in higher shear bond stresses. No significant difference is found between specimens, gritted with river gravel or crushed stone. Applying the adhesive layer with the toothed paddle in horizontal direction slightly improves the bond behaviour. Finally, the experimental results of the test members with a smooth epoxy layer without gritted aggregates, provide test data for a fracture mechanics approach, which uses a 2D numerical model of the test specimen, composed of steel, epoxy resin, and concrete.

Abstract: Despite the expanded application for zirconia in restoration dentistry, there is less clear recommendation in the literature regarding the relation between zirconia surface roughness and its shear bond strength to resin cements. The aim of this study was to assess the effect of surface roughness of Cercon zirconia on its shear bond strength to resin cements. 66 Zirconia rectangular specimens (10 mm×10 mm×3 mm) were prepared from Cercon zirconia blocks, finished using a diamond rotary cutting instrument, sintered, and then assigned into 6 groups. The specimens in the first group without polishing were used as control. Other groups were polished against 120#, 240#, 360#, 500# and 600# sand paper after sintered, respectively. Ceramic surface were analyzed by scanning electron microscopy (SEM) and Surface profilometer. 10 samples of each group were bonded with Variolink N resin cements respectively and submitted to shear bond strength test. Shear bond strength was measured and statistically analyzed. The results showed that the population means of 6 groups of samples were not equal. There was no significant difference between control group and 600# sand paper treated group, 500#, 360# and 240# sand paper treated groups (P>0.05), but a significant difference among the other groups (P<0.05). Findings of this study revealed that the shear bond strength might be raised by increasing the surface roughness of Cercon zirconia. Therefore, the surface roughness of Cercon zirconia has an effect on the shear bond strength, but is not the determining factor in clinical use.