جستجوی مقالات مرتبط با کلیدواژه « Bonding agent » در نشریات گروه « پزشکی »

Sandwich technique is one of the most common methods in dentistry in which resin-modified glass ionomers due to advantages such as fluoride release and adhesion to tooth structure are used with composite restorations. The aim of this study is assessment of shear bond strength between resin modified glassionomer and composite using different bonding agents.
Material and In this invitro study, 60 resin modified glass ionomer samples (GC FUJI 2LC) were prepared. .In the first group, without the use of bonding agent and in other two groups with the use of bonding agents( SE bond and S3 bond) composite adhered to glass ionomer.After placing the samples in distilled water in incubator with temperature 37/5° C for one week, shear bond strength of samples was measured by the universal machine test . One way analysis of variance and Tukey test were used for analyzing the data and comparison between groups.
The maximum amount of the bond strength was for specimens bonded with SEbond(13/09 Mpa) and the lowest amount was in control group(5/3 Mpa) . The mean shear bond strength was significantly different between the four groups.(p The maximum shear bond strength between resin-modified glass ionomer and composite resin was related to SE bond therefore using of this bonding agent in sandwich technique is recommended.

Although bleaching is an effective way in creating a beautiful smile, there is a controversy about the effectiveness of bleaching agents on composite restored teeth. Therefore, this study aimed to evaluate the effect of carbamide peroxide (CP) at different concentrations on shear strength (SS) of a bonded nanocomposite to enamel and dentin.
Material and In this in-vitro study, 96 premolar teeth were divided into two groups. Buccal surfaces were abraded to reach enamel or dentin surfaces. The specimens were mounted in acrylic cubs and bonding procedures were performed using Single Bond 2. A composite cylinder was formed on surfaces using Z350 nanohybrid composite and then, the specimens were divided into four subgroups: 1: the control; 2, 3, and 4 bleached with Opalescence PF 10, 15, & 20% in 8, 6, & 4 hours a day, respectively. The SS were measured and the data were analyzed using one-way ANOVA followed by Tukey multiple comparisons test.
There was a reduction in SS in both groups after bleaching. This reduction was not statistically significant in the enamel subgroups (P=0.589), but it was statistically significant in the dentin subgroups. This significance was only between the control and fourth subgroups (P=0.005).
According to this study, if bleaching with CP is performed on a nanocomposite restoration with dentinal margins, replacing the restoration should be taken in to consideration. Increasing the CP concentration leads to more deterioration of dentinal bond. Enamel bond is less affected.

Sandwich technique is one of the most common methods in dentistry, in which resin-modified glass ionomers are used with composite restorations due to special features, such as fluoride release and adhesion to tooth structure. This study aimed to assess shear bond strength between resin-modified glass ionomer and composite using bonding agents with different solvents.
In this in vitro study, 80 resin-modified glass ionomer samples (GC FUJI 2LC) were prepared. Composite was adhered to glass ionomer without the use of bonding agent in the first group and with the use of bonding agents in other three groups (single bond, one step plus and TG bond). After preserving the samples in distilled water in incubator at the temperature of 37.5°C for one week, shear bond strength of the subjects was measured using universal testing machine. Data analysis and comparison of the groups were performed using one-way analysis of variance and tukey post hoc.
In this study, the maximum amount of bond strength was observed in TG bond group (12.99 Mpa), whereas the lowest amount was found in the control group (5.3 Mpa). Results revealed a statistically significant difference between the groups in terms of mean shear bond strength (P=0.001).
According to the results of this study, the maximum shear bond strength between resin-modified glass ionomer and composite resin was related to TG bond. This could be due to the presence of water in the composition of bonding agent, which acted as a moisturizing agent of glass ionomer and led to greater adhesion of composite to glass ionomer.

Microleakage is the most important reason for secondary caries and treatment failure. The aim of this study was to evaluate the effect of liner (flowable composite) and bonding agents on microleakage of resin composite (z250) in class II cavities.
Standardized Class II cavities were prepared on mesial and distal of 80 human premolars. The teeth were divided into eight groups based on the position of gingival marginal, bonding agent and liner. Thus, the classification of groups were as follows: group I: margin (1mm sub CEJ), bonding (single bond,3M), and resin composite(z 250,3M), group II: flowable composite (filtek flow, 3M) as a liner, the rest similar to group I. group III: margin (1mm supra CEJ), the rest similar to group I, group IV: margin (1mm supra CEJ), the rest similar to group II, group V: bonding (Adper easy bond,self-etch,3M), the rest similar to group I, group VI: bonding (self-etch), the rest similar to group II, group VII: self-etching bonding, the rest similar to group III, and group VIII: self-etching bonding, the rest similar to group IV. All the samples were thermocycled (3000 times) and placed in 10% metylen blue dye, then sectioned with diamond disk. They were evaluated using a stereomicroscope (40 x). The data were analyzed by one way variance and tuky test (p Concerning sub-CEJ margin, the greatest microleakage was in group I and the least was in group VI (P>0.05). Concerning supra-CEJ margin, group III had the greatest microleakage while group VIII had the least.(p>0.05). The comparison between groups showed significant differences between groups I and VIII (p Combination of self-etch adhesive with flowable resin composite (liner) as a packable resin composite z250 decreases microleakage.

As in fissure sealant therapy the tooth surface is mostly enamel, the use of an enamel bonding agent (hydrophobic bonding agent) may be more cost effective than that of newer generations of bonding (hydrophilic bonding agents). The aim of this study was to compare the retention and durability of fissure sealant therapy when applying an enamel bonding agent, a dentin bonding agent and no bonding agent during 4 years.
This study was done on the first permanent molars of the upper and lower jaws of 24 students of the first grade of a primary school (6-7 years old). On 36 teeth, a dentin bonding agent (Excite) was applied under the fissure sealant and on 36 teeth an enamel bonding agent (Margin bond) was applied under the fissure sealant. Then, 24 teeth were selected from these two groups and were compared with a group (including 24 teeth) with no bonding agent under the fissure sealant (as control group). All the fissures of the teeth were evaluated annually for 4 years to find out the presence or absence of fissure sealant substance. Data were analyzed using Wilcoxon test.
From the statistical analysis, there was no significant difference in retention and durability of the fissure sealant substance comparing the group with dentin bonding agent (Excite) and the group with enamel bonding agent (Margin bond). Also, using a bonding agent made no significant difference (P>0.05).
According to the results of this study, using a bonding agent made no improvement in the retention and durability of fissure sealant substance.

Prevention of contamination during the procedural steps is a requisite for achieving a satisfactory composite restoration. The aim of this experimental study was to compare the shear bond strength of composite to enamel in two different decontamination procedures of uncured bonding and uncontaminated conditions. Thirty-six extracted sound human premolars and incisors were selected. Enamel of buccal surface was ground flat. The teeth were divided into 3 groups of 12 each. In the control group (1), 3M Single Bond adhesive was used according to the manufacturer’s instructions, without any contamination. In groups 2 and 3 uncured adhesive was saliva contaminated and then: (2) rinsed, dried, etched (5 seconds), rinsed, dried, adhesive was reapplied and (3) cured, dried, etched (5 seconds), rinsed, dried and adhesive was reapplied. Then composite cylinders were bonded to enamel surfaces.Finally, samples were sheared using Instron testing machine and shear bond strength data were subjected to one-way ANOVA. The mean bond strength was 16.5317 MPa in the control group, 16.2308 MPa in rinsed contaminated bonding group and 15.8025 MPa in cured contaminated bonding group. No statistically significant difference was found in the mean shear bond strength of groups 1,2 and 3 (p=0.954). Both decontamination protocols (groups 2 and 3) resulted in acceptable bond strength and both were comparable with uncontaminated condition.

Lack of dental materials with adequate adhesion and sealing properties and the resultant microleakage is a major concern in dentistry. The use of denting bonding agents(DBA) in sealant therapy and their effect on microleakage remains controversial. This study was conducted with the aim to evaluate the level of microleakage in fissure sealants with and without DBA. In this experimental study, 45 sound premolars which were suitable for sealant application were chosen and assigned randomly into three groups. Sealant was applied to all teeth with the same conventional technique. In the first group, fissure sealant was applied without bonding agent, in the second group, it was used with total etch bonding agent (single/3M), and finally in the third group it was applied with self-etch bonding agent (G-bond/GC). Microleakage assessment was done by a stereomicroscope. Results were evaluated with Mann-U-Whitney and one way-ANOVA tests. This study was performed on 45 tooth samples. In the first group, %7 and in the third group, %7 had no leakage. In the second group, %60 of specimens had no leakage. The amounts of microleakage in control, experimental 1 and 2 were 42.6%,12% and 37.3% respectively, and their difference was significant (P < 0.001). Single-bond significantly increased the retention of sealant (P < 0.05). It seems that the best practice for the placement of sealants remains enamel preparation with acid etch and the use of an intermediate bonding layer. The results showed that using 5th-generation bonding agent in comparison with 7th-generation bonding agent and not using any bonding decreased microleakage

In many studies reduction in bond strength of bleached enamel has been pointed out. The decrease in bond strength raised concern in cosmetic dentistry. However, there is little information about the effects of bleaching, on reduction of enamel bond strength in new bonding systems. This study aimed to investigate the effects of three dental bonding agents on shear bond strength of a composite to bleached enamel. In this in vitro study, sixty intact bovine mandibular incisors were collected and randomly divided into six groups (n=10). In group A, the facial enamel was etched with 35% phosphoric acid gel, then a single layer of bonding agent (SingleBond, 3M, ESPE) was applied and light-cured for 40 seconds by a light-curing device (ColtoluxII colten) with 400 mw/cm²light intensity according to the manufacturer’s instructions. In group B: after etching of enamel surfaces, Clearfil SE-Bond (Kuraray Medical Inc.) was used. In group C: after etching of enamel surface, Clearfil S3 Bond (Kuraray, Medical Inc.) was used. In groups D, E, and F 35% carbamide peroxide (Opalescence, Ultradent Products Inc.) was applied on the enamel surfaces for 5 hours according to the manufacturer’s recommendations. Afterwards the specimens were rinsed thoroughly with distilled water for 60 seconds and dried with compressed air. Immediately after bleaching, bonding regimes similar to groups A, B, and C were carried out in groups D, E, and F, respectively. Then, cylinders of hybrid composite were bonded to the facial enamel surface of all specimens, using 3 dental bonding agents. After 24 hours, the specimens were ther mo cycled (5–55°C, 1000cycles), and then subjected to shear bond testing by a universal machine Zwick (Zo20, Germany). The data were analyzed by one- and two-way ANOVA and post hoc tests. All statistical tests were performed with SPSS version 11. The mean shear bond strength of SingleBond to bleached and unbleached enamel was 8.36 ± 3.30 and 20.17 ± 6.52 MPa, respectively. For Clearfil SE bond, bleached enamel exhibited bond strengths of 12.25 ± 6.61Mpa and unbleached enamel exhibited a bond strength value of 17.66 ± 5.82 Mpa. The bond strength for Clearfil S3 bond was 6.66 ± 2.57 Mpa to bleached and10.40 ± 3.65Mpa to unbleached enamel. Shear bond strength of hybrid composite to bleached enamel in three experimental groups decreased but this reduction was not statistically significant for Clearfil SE bond.

Contamination of etched enamel to saliva before placement of sealant prevents the appropriate bonding and results in microleakage. Using bondings is effective for decreasing the microleakage. This experimental study aimed to evaluate the effect of bonding agent on microleakage of a fissure sealant before or after contamination to saliva.

In this experimental study 40 sound premolar teeth were randomly divided into four groups. The prophylaxis was done and the teeth were etched with 37% phosphoric acid gel, then they were washed and dried. In the first group, Seal-Rite fissure sealant and Dentastic (Pulpdent, USA) without saliva contamination, and in the second group sealant with bonding agent after saliva contamination for 10s, were applied and cured for 40s. In the third group, fissure sealant without bonding agent or saliva contamination, and in the fourth group fissure sealant without bonding application was applied after contamination with saliva and then was cured. After thermocycling, the teeth were placed in 50% silver nitrate for 2 hours. The buccolingual sections were applied and microleakage evaluation was made by stereomicroscope at 4X magnifications and results were evaluated with mann-whiteny test.

The fissure sealant group without bonding agent showed the most microleakage after contamination to saliva and use of sealant with bonding agent significantly showed decrease of microleakage.

Use of bonding agent under fissure sealant in saliva-contamination status is beneficial for decreasing microleakage.

Statement of Problem: Porcelain restorations are susceptible to fracture and a common method for repairing is the use of silane and composite on etched porcelain. Although HF is very effective in porcelain etching but has detrimental effects on tissues. In this study, the effect of APF and PHA was compared with HF in porcelain etching. Also the role of silane, unfilled resin and dentin bonding in bond strength of composite- porcelain was evaluated. Methods and Materials: In this experimental in-vitro study, one-hundred twenty porcelain square blocks (2×5×5 mm) were prepared and bonding surfaces of each sandblasted. Samples were divided into three groups. The first group (n=40) were etched with buffered HF 9.5% (Ultradent) for 1 min., the second group (n=40) were etched with Iranian APF 1.23% (Kimia) for 10 minutes and the third group (n=40) were etched with Iranian PHA 37% (Kimia) for 1 min. Ultradent silane was applied on the surfaces of half of cases in each group. On the surfaces of half of silane-treated samples unfilled resin was applied and dentin bonding was used on the surfaces of the remaining. Samples without silane were treated in a similar manner. Composite cylinder with 4mm diameter and 2 mm height was bonded to porcelain. Specimens were stored in 37°C distilled water for 24 hours and subjected to 500 cycles. Shear bond strength was measured with an Instron machine and type of fracture was evaluated using a stereomicroscope. Results were analyzed using 3 way ANOVA, Kaplan- Maier and Tukey HSD tests. Findings showed that PHA and APF roughened the porcelain surface without creating retentive micro undercuts but HF etches porcelain and creates retentive microundercuts. Ultradent silane had no significant effect on bond strength of porcelain- composite. Unfilled resin with Ultradent silane compared with dentin bonding with the same silane is more effective in bond strength of composite- porcelain. Based on present study, application of Ultradent silane on sandblasted and etched porcelain with PHA or APF cannot be used as an alternative to this silane on sandblasted and etched porcelain with HF.

Dentine bonding systems are usually unfilled, and so their shrinkage may be significant. High shrinkage may cause internal stress at the interface between resin-composite restoration and the dentine substrate. Failure of the adhesive interface may be observed due to the interna! stress. The aims of this study were:A) To obtain a suitable method for measuring the kinetics of polymerisation shrinkage in unfilled resm at different thicknesses, particularly for thin films.B) Consideraing the effect of thickness on shrinkage.Scotchbond Multipurpose (3M) adhesive bond resin was used. To overcome the particular challenges presented by thin films, a filled-ring measurement procedure was used. Also, a non-contact laser analogue displacement sensor system was developed and applied to measure polymerisation shrinkage. Regression analysis was performed on a complete data set. Non-linear regression analysis established a logarithmic relationship between polymerisation shrinkage and layer thickness. The method applied in this study was found to be sensitive and accurate procedure for determining photo-polymerisation shrinkage of thin films. Polymerisation shrinkage increased with logarithmic of the adhesive thickness.