Total-etch Mode Research Articles

The effect of different treatment protocols on shear bond strength in resin composite restoration repair

BackgroundIt was aimed to investigate the effect of sandblasting and laser surface treatment on shear bond strength in composite restoration repair in vitro.MethodsA micro-hybrid composite (Filtek Z250, 3 M-ESPE, USA) was used to prepare 120 samples. The samples were subjected to a thermal cycle test 5,000 times between 5 and 55 0C, and they were randomly divided into 12 groups (n = 10). No surface treatment was performed in Groups 1 to 4, which were designed as control groups. The surfaces of the samples in Groups 5 to 8 were sandblasted with a Cojet device, and the surfaces of the samples in Groups 9 to 12 were applied Er, Cr: YSGG laser. After the sample surfaces were divided into groups with and without acid etching, universal adhesive was applied, and the repair process was performed using Filtek Z250 or nano-filled resin composite (Filtek Ultimate, 3 M-ESPE, USA). The thermal cycle test was repeated 5,000 times between 5 and 55 0C on all repaired samples. The repair shear bond strength of the samples was measured using a universal testing device (Shimadzu IG-IS, Kyoto, Japan). The fracture types were evaluated by optical microscopy and scanning electron microscopy (SEM). Statistical analyses of the findings were evaluated by the Kruskal Wallis test and Mann Whitney U test at 0.05 significance degree.ResultsThe highest mean shear bond strength values were obtained from the samples sandblasted with CoJet, followed by Er, Cr: YSGG laser, and the control group. It was determined that there was a significant difference between the mean shear bond strength values obtained from the control group and the other surface treatment groups (p < 0.05). In general, significantly higher mean shear bond strength values were obtained when the universal adhesive was applied in total-etch mode compared to the application in self-etch mode (p < 0.05). Additionally, it was determined that higher shear bond strength values were obtained with Filtek Ultimate compared to Filtek Z250 (p < 0.05).ConclusionWithin the limitations of this study, it can be concluded that the use of universal adhesive in total-etch mode, in addition to surface treatments on the resin composite surface in the repair protocol and the use of nano-filled resin composite as repair material can increase the mean shear bond values in repair.

Evaluation of Shear Bond Strength of Universal Adhesives to Dentin: in Vitro Study

Aim: Universal adhesives are widely used in restorative dentistry. The aim of this study was to evaluate the shear bond strength (SBS) of universal adhesives to dentin in different application modes. Materials and Methods: The study utilized seven universal adhesives and one total-etch adhesive. The sixty-four extracted intact human molars used in the study were embedded in acrylic blocks to the enamel-cement junction. The occlusal surface was removed to expose the dentin surface. After applying self-etch and total-etch adhesives to the dentin, flowable composite (Clearfil Majesty Flow, Kuraray) was placed in a transparent mold (2.38 mm diameter and 2 mm height) and polymerized. After thermal aging (1000 cycles), a SBS test has been carried out on a universal testing machine. The fracture types formed on the surface of the teeth were examined under a microscope. Data were analyzed by two-way analysis of variance (ANOVA) test (p&lt;0.05). Results: SBS values of universal adhesives on dentin showed statistically significant differences according to adhesive and application mode (p&lt;0.05). Total-etch application produced statistically higher SBS than self-etch application (p&lt;0.05). The two-step universal adhesive (G2 Bond Universal) had the highest SBS in both the self-etch and total-etch application modes (p&lt;0.05). When the bond surfaces of the universal adhesives were examined, fractures occurred most frequently in the adhesive type. Conclusion: The use of universal adhesives in the total-etch mode results in greater bond strength to dentin tissue. Universal adhesive type influences bond strength.

The effect of stannous fluoride desensitizing toothpaste on immediate dentin sealing ability of universal adhesive in vitro

Background/purposeThe stannous fluoride pretreatment of dentin may compromise the bond formation of the dentinal adhesive system. This study aimed to determine the effect of stannous fluoride (SnF2) desensitizing toothpaste on immediate dentin sealing ability (IDS) of universal adhesive in human intact dentin using dentin permeability test and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Materials and methodsSixty sound dentin specimens were prepared from 60 extracted intact third molars, then treated with 17 % EDTA for 60 s to simulate hypersensitive dentin, and randomly divided into 2 series. Series 1 (dentin permeability test; n = 40) had 4 different treatment groups: (1) universal adhesive (self-etch mode), (2) universal adhesive (total-etch mode), (3) SnF2 pretreatment + universal adhesive (self-etch), (4) SnF2 pretreatment + universal adhesive (total-etch). The IDS of each group was the percentage decrease of hydraulic conductance of dentin after bonding. Series 2 (n = 20) was SEM-EDS analysis of different treated dentin before bonding. The data were analyzed using 2-way ANOVA and Tukey test. ResultsIn groups of no SnF2 pretreatment, the IDS of universal adhesive were 79.53 ± 20.71 and 77.34 ± 18.14 % for self-etch and total-etch mode, respectively. In groups of SnF2 pretreatment, the corresponding values were 71.54 ± 15.56 and 69.56 ± 9.92 %, respectively. Although SnF2 pretreated-dentin had the remarkable signals of silicon and tin, there were no significant reductions in the IDS of universal adhesive (P < 0.05). ConclusionSnF2 desensitizing toothpaste has no adverse effect on the immediate dentin sealing ability of universal adhesive.

Effects of Endodontic Irrigants on Shear Bond Strength of Mild Universal Adhesives to Dentin

PurposeThe objective of this in vitro study was to evaluate the shear bond strength (SBS) of several universal adhesives to dentin treated with sodium hypochlorite (NaOCl), and NaOCl followed by ethylenediaminetetraacetic acid (EDTA). Materials and MethodsAdhese Universal, Scotchbond Universal, Prime & Bond Elect, Prime & Bond Active, and Optibond XTR were included in the study. SBS values were determined in self-etch mode with no pretreatment of the dentin, after a 20-minute exposure of the dentin to 6% NaOCl, and after a 20-minute exposure to NaOCl followed by a one-minute exposure to 17% EDTA. Experimental groups were repeated using a total-etch technique (except Optibond XTR). ResultsAdhesives in self-etch mode had significantly reduced SBS following dentin exposure to NaOCl (P < .05), while with a total-etch technique, only Prime & Bond Active was affected (P < .05). SBS in self-etch mode when NaOCl exposure was followed by EDTA were equal to or higher than negative control values (P < .05). For total-etch groups, Adhese Universal was negatively affected by NaOCl + EDTA exposure (P < .05). Prime & Bond Elect exhibited lower SBS following NaOCl + EDTA exposure when compared to just NaOCl exposure but was not different from the negative control (P < .05). ConclusionFor the adhesives tested, the use of 17% EDTA following NaOCl exposure negated the negative effects of NaOCl on SBS in self-etch mode. When used in total-etch mode, results varied significantly, with some adhesives performing better or worse depending on the specific testing condition.

Effect of photodynamic therapy with two photosensitizers on the microtensile bond strength of a universal adhesive to affected dentin

BackgroundThis study aimed to evaluate the impact of photodynamic therapy (PDT) using two photosensitizers, methylene blue and indocyanine green, on the microtensile bond strength of a universal adhesive to caries-affected dentin. MethodsThe occlusal enamel of 60 third molars was cut to expose the inner one-third of the dentin. Artificial caries were induced through a pH cycling process. The samples were divided into three groups: M (Methylene blue+ diode laser), I (Indocyanine green agents+ diode laser irradiation), and control. Each group was further divided into two subgroups according to the adhesive protocol (self-etch, total-etch). After restoring with Gradia composite resin, teeth were sectioned and exposed to 5000 thermal cycles. Microtensile bond strength was measured using a universal testing machine. The data were subjected to two- and one-way ANOVA and paired comparisons were performed by the Tamhane and Tukey tests. ResultsThe study found significant effects of the photosensitizer, etching pattern, and their interactions on the microtensile bond strength of composite resin to caries-affected dentin (P < 0.001). In the self-etching mode, PDT with indocyanine green exhibited significantly higher bond strength values compared to PDT with methylene blue (P = 0.001) and the control groups (P < 0.001). However, no significant differences were observed in the total-etch mode. (P = 0.54). ConclusionsThe etching mode played a more significant role in the bond strength when using the universal adhesive alongside PDT with methylene blue and indocyanine green. Employing two photosensitizers in PDT during the self-etch mode significantly increased the bond strength values.

Influence of Diabetes Mellitus and Universal Adhesive Application Mode on the Bond Strength of Composite Resin to Dentine.

The aim of the current study was to evaluate the influence of diabetes mellitus and the mode of applying a universal adhesive on the shear bond strength of composite resin to dentin. Forty teeth were extracted from diabetic individuals who had been living with diabetes for a period of 5 to 15 years. These forty teeth were divided into two groups: twenty molars from patients with type 1 diabetes and twenty molars from patients with type 2 diabetes. The remaining twenty sound human molars were collected from non-diabetic patients. The collected teeth were assigned into 3 groups, and each group was further divided into 2 subgroups. Group A (n = 20): non-diabetic (ND) where sub group IA: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIA: Universal adhesive applied in the self-etch mode (n = 10). Group B (n = 20): diabetic type 1 (D1) where sub group IB: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIB: Universal adhesive applied in the self-etch mode (n = 10). Group C (n = 20): diabetic type 2 (D2). Where Sub group IC: Universal adhesive applied in the total-etch mode (n = 10) and sub group IIC: Universal adhesive applied in the self-etch mode (n = 10). A Teflon mold measuring 3mm in diameter was attached to the dentin surface, used to build Filtek Z550 to a height of 3mm. The specimens were fixed to the universal testing to measure shear bond strength. There was a statistically significant difference of Mean ±SD of shear bond strength among the three tested groups. In group A, the Mean ±SD were (21.710 ± 0.638), it was decreased in group B to (14.626 ± 0.726) and group C to (17.740 ± 0.668). Subgroup I had lower shear bond strength values than subgroup II in all tested groups. The difference between each subgroup in groups A, B, and C was significant. 1. Diabetes mellitus has an adverse effect on the shear bond strength of composite to dentine. 2. Type 1 diabetes mellitus significantly reduces the shear bond strength of composite resin to dentin. 3. Shear bond strength of the universal adhesive was higher when applied to dentin using the self-etch mode, as compared to the total etch mode, in all groups, regardless of whether the participants had diabetes or not. Key words:Diabetes Mellitus, Universal Adhesive, Application Mode, Shear bond Strength, Dentine, Composite.

Effect of at-home and in-office bleaching on microleakage of class V composite resin restorations using different types of universal adhesives: An in vitro study.

When bleaching agents contact dental structures, they act on restorative materials and adhesive interfaces. This study investigated the effect of "at-home" and "in-office" bleaching on the microleakage of composite resin restorations performed with different universal adhesives in self-etch and etch-and-rinse modes. Class V cavities were prepared in 132 premolars. The samples were divided into four groups (n=33). All Bond Universal adhesive was used in the first and second groups, and G-Premio Bond adhesive was used in the third and fourth groups. The total-etch mode was used in the first and third groups, and the self-etch mode was used in the second and fourth groups. The samples were divided into three subgroups (n=11). In the first subgroup, home bleaching was used, and in the second subgroup, office bleaching was used. In the third subgroup, bleaching was not performed. The specimens were examined under a stereomicroscope for microleakage. Ordinal regression analysis was applied (P<0.05). The adhesive type, application method, and margin type significantly affected microleakage (P<0.05). The amount of microleakage in All Bond Universal adhesive was significantly higher than in G-Premio Bond adhesive. The chance of microleakage in the self-etch mode was almost twice as high as in the etch-and-rinse mode. The bleaching method did not significantly affect microleakage (P>0.05). Based on the results of the microleakage test, bleaching after composite resin restorations did not significantly affect the microleakage of Class V restorations.

What is the most effective technique and composite for bonding aligner attachments to primary enamel?

Objectives: This in vitro study evaluated the shear bond strength (SBS) of aligner attachments bonded to primary teeth with different techniques and composites. Material and Methods: Eighty attachments were prepared using five composites: An aligner composite (GC aligner connect [GAC]), two flowable restorative composites (G-aenial universal injectable and Estelite universal super low flow), and two one-step orthodontic composites integrated with primer (GC ortho connect flow and GC ortho connect). Aligner and restorative composites were applied with self- or total-etch (SE or TE) modes of universal adhesive (G-Premio Bond). Self-adhering composites integrated with primer were applied after acid etching. Excessive composites were removed with tungsten carbide burs after the polymerization of resin attachments. All primary teeth were exposed to thermocycling. Bond strength was determined with a universal testing machine. Remnant resin attachment was scored with the resin attachment remnant index. Kruskal–Wallis, Mann–Whitney, and Chi-square tests were used for statistical analyses. Results: The self-etching technique demonstrated lower SBS values compared to total-etching and self-adhering groups regardless of composite type. The highest SBS was found with aligner composite (GAC) and the total-etching technique. Self-adhering composites showed sufficiently high SBS values comparable with GAC and TE bonding techniques. The amount of remnant attachment was significantly higher in the total-etching and self-adhering groups compared to SE bonding with GAC (P &lt; 0.05). Conclusion: Self-adhering orthodontic composites can be preferred to simplify the bonding of aligner attachments to primary enamel after acid etching.

The effect of dentin surface pretreatment using dimethyl sulfoxide on the bond strength of a universal bonding agent to dentin

BackgroundThis study aimed to evaluate the effect of dentin pretreatment by Dimethyl Sulfoxide (DMSO) on the bond strength and microleakage of a universal bonding agent to dentin.MethodsFifty-six dentinal discs (thickness = 2 mm) were obtained from the crowns of the human third molars. The disks were assigned into 4 groups and treated as follows; self-etch-control group: G-Premio universal adhesive was used in self-etch mode, total-etch-control: G-Premio universal adhesive was used in total-etch mode, self-etch-DMSO: Water-based DMSO (50% volume) was applied on the samples for 60 s followed by application of G-Premio universal adhesive in self-etch mode, and Total-etch-DMSO: The samples were etched, and then, water-based DMSO was applied on them for 60 s followed by the application of G-Premio universal adhesive in total-etch mode. Afterward, resin composite was placed on all samples and light-cured. The samples were kept in distilled water and subjected to 5000 thermal cycles. Microshear bond strength was measured using the universal testing machine and failure modes were analyzed using a stereomicroscope. Forty-eight human third molars were used for microleakage evaluation and a standardized class five cavity was prepared on the buccal surface of each tooth. The teeth were assigned into 4 groups and received aforementioned surface treatment and the cavities were filled with resin composite. After storing in water for 24 h, the samples were subjected to 5000 cycles of thermocycling and the microleakage level of the samples was evaluated using silver nitrate uptake at the bonded interface. Two-way ANOVA test was used to analyze the effect of bonding technique (self-etch/ total-etch) and DMSO pretreatment on the microshear bond strength and microleakage of G-Premio adhesive to dentin.ResultsBonding technique had no effect on the bond strength values (p = 0.17) while DMSO pretreatment significantly decreased the microshear bond strength of the samples (p = 0.001). DMSO application increased microleakage significantly in total-etch (P-value = 0.02) while it had no effect in self-etch mode (P-value = 0.44).ConclusionsPretreatment of dentin using 50% DMSO significantly reduced the bond strength of G-Premio Bond in both self-etch and total-etch modes. DMSO effect on microleakage depended on the etching technique; DMSO increased the microleakage level when the adhesive was used in total-etch mode while did not affect the microleakage in self-etch mode.

The Influence of Chlorhexidine Gluconate Dentine Pre-Treatment on Adhesive Interface and Marginal Sealing.

Background and Objectives: The aim of this in vitro study was to evaluate the combined effect of a 2% chlorhexidine aqueous solution and a universal adhesive system applied in self-etch and etch-and-rinse strategies on the composite resin-dentin interface. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of forty caries-free molars extracted for orthodontic reasons. The samples were randomly divided into two groups corresponding to the used etching protocol: I-etch-and-rinse; II-self-etch. In each tooth, one cavity was assigned for the control subgroups -IA (n = 20) and IIA (n = 20)-adhesive only, and the opposite cavity was pretreated with a 2% chlorhexidine solution-Gluco CHeX Cerkamed-subgroups IB (n = 20) and IIB (n = 20). Both sets of groups were restored using a universal adhesive system (Single Bond Universal Adhesive, 3M-ESPE) and a bulk-fill composite resin (Filtek One Bulk Fill Restorative, 3M-ESPE). The roots and the pulp tissue were then removed, and a needle connected to a perfusor with 100 mL saline solution was used for pulp pressure simulation with a hydrostatic pressure of 20 cm H2O. Cariogenic attack was simulated using a demineralizing solution for 3 days at a constant temperature of 25 °C. The teeth were then sectioned in a facial-lingual direction and the microleakages at the occlusal and cervical margins were registered and scored using an optical Carl-Zeiss AXIO Imager A1m microscope (Carl-Zeiss). The composite resin-dentin interface was analyzed using a SEM Vega Tescan LMH II. Statistical analysis was performed using the Kruskal-Wallis test with a significance level of p < 0.05. Results: Microleakage evaluation showed no significant differences among the study groups (p > 0.05). In subgroup IA, significant differences were recorded between occlusal and cervical margins (p < 0.05). Conclusions: Application of chlorhexidine on tooth substrate before using a universal bonding system in total etch or self-etch mode has no influence on the adhesive interface in the condition of cariogenic attack. The thickness of the adhesive resin layer seems to be less uniform when using chlorhexidine, but the morphological differences at the adhesive interface have no influence on the sealing capacity of the universal bonding system, regardless of the etching strategy.

The Effect of Dental Adhesive Composition and Etching Mode on Microleakage of Bonding Agents in Primary Molar Teeth.

The dilemma of microleakage at the composite-tooth interface is still a major challenge in operative dental practice. This study aimed to compare the microleakage of universal adhesive with self-etch and total-etch bonding strategies for restoration of class-II primary molar cavities. This in vitro, experimental study was conducted on 75 extracted primary molars. Class-II cavities were prepared in mesial or distal surfaces. The teeth were randomly divided into five groups of Adper Single Bond 2 (3M ESPE; St Paul, MN, USA), Clearfil SE Bond (Kuraray Noritake, Osaka, Japan), G-Bond (GC Corp., Tokyo, Japan), G-Premio Bond (GC Corp., Tokyo, Japan) with total-etch mode and G-Premio Bond with self-etch mode. Cavities were also restored with Nano-hybrid resin composite (Grandio, VOCO, Cuxhaven, Germany) and incubated for 24 hours, followed by thermocycling at 1500× between 5-55°C within a dwell time of 20 seconds. Later, the cavities were placed in 1M silver nitrate solution and evaluated under a stereomicroscope. Finally, microleakage was assessed quantitatively and qualitatively. One tooth in each group was prepared and evaluated under a scanning electron microscope (SEM). Data were analyzed using One-way ANOVA, Tukey's post hoc test and Chi-square test (p< 0.05). The microleakage values were significantly different in the study groups (p&lt; 0.05). The highest level of microleakage was noted in G-Bond and the lowest in G-Premio Bond with total etching. There was a significant correlation between the qualitative and quantitative measurements of microleakage. The G-Premio Bond yielded acceptable results in terms of microleakage in total-etch and self-etch modes. However, additional etching is recommended to improve the quality of bonding.

Shear bond strength and failure modes of composite to dentin under different light-curing conditions

This study aimed to examine the effects of different light-curing modes on the immediate shear bond strength (SBS) of different composite resin types to dentin using universal adhesive. Human teeth were extracted and sectioned to obtain flat dentin slices. The universal adhesive was applied in total-etch mode. Conventional and bulkfill composites were used to create cylindric build-ups. Full power and Ramp mode were used to light-cure the adhesive and composite resin. SBS test was performed in a universal testing machine, and failure modes were determined via scanning electron microscopy (SEM). Two-way ANOVA and Student t-test were used to analyze statistical data. Significantly higher SBS was obtained when bulkfill composite was used compared to the conventional one ( p &lt; .001). The difference between Full power and Ramp curing mode was insignificant ( p = .4). Mixed failure was the predominant type. Low SBS resulted in adhesive failure, while high SBS resulted in cohesive failure. Shear bond strength was not curing-dependent but rather material-dependent. Ramped curing does not contribute to higher bond strength. Bulkfill composite seems to be more favourable in terms of bond strength.

Application Modes Affect Two Universal Adhesive Systems' Nanoleakage Expression and Shear Bond Strength.

Objectives The aim of this study was to evaluate the shear bond strength and the nanoleakage expression of CLEARFIL Universal Bond Quick and Tetric N-Bond adhesive systems bonded to dentin. Materials and Methods 100 freshly extracted human premolar teeth were utilized. The teeth were sectioned to expose dentin. All dentin specimens were assigned into 4 experimental groups; 2 groups had Universal Bond Quick (Universalself group) and Tetric N-Bond (Tetricself group) applied in the self-etch mode, while 2 groups had Universal Bond Quick (Universaltotal group) and Tetric N-Bond (Tetrictotal group) applied in the total-etch mode. n = 15 for shear bond strength and n = 10 for nanoleakage experiment. One-way ANOVA and Kruskal-Wallis test were utilized to analyze the shear bond strength test and the nanoleakage expression, respectively. Results The highest significant bond strength value was recorded by the Tetricself specimens (p < 0.05) when compared to the remaining three groups. There were no statistically significant differences between the shear bond strength values recorded in the Tetrictotal, Universalself, and Universaltotal groups (p < 0.05). Both bonding systems applied in the self-etch mode (Universalself, Tetricself) had no silver nitrate deposits in the hybrid layer and the hybrid layer-adhesive interface (p < 0.001); however, both bonding systems applied in the total-etch mode (Universaltotal, Tetrictotal) had silver nitrate deposits in the hybrid layer, the hybrid layer-adhesive interface, and the bonding layer (p < 0.001). Conclusion Applying the Universal Bond Quick and Tetric N-Bond in the self-etch mode exhibited better results in terms of nanoleakage expression. Universal Bond Quick showed the stability of the shear bond strength to dentin when applied using the total-etch or self-etch modes. Tetric N-Bond showed significant deterioration in bond strength when applied in the total-etch mode and exhibited the highest bond strength when applied in the self-etch mode.

Universal Adhesive for Fixed Retainer Bonding: In Vitro Evaluation and Randomized Clinical Trial.

This study aims to assess the efficacy of a universal adhesive (Scotchbond Universal, 3M ESPE) (SB) in total-etch mode, compared to a traditional orthodontic primer (Transbond XT Primer, 3M ESPE) (XT Primer), to perform bonding of orthodontic fixed retainers along with the Transbond XT Light Cure Adhesive Paste (3M ESPE). For the in vitro study, a round section wire (Ortosmail Krugg) was bonded using XT Primer for 20 bovine incisors (Group 1) and SB for other 20 (Group 2). Samples were debonded in a universal testing machine applying a tangential force to specimens (crosshead speed of 1 millimeter per minute). Shear bond strength (SBS) and adhesive remnant index (ARI) scores were calculated. For the in vivo study, 100 patients needing upper and lower canine-to-canine fixed retainers after orthodontic treatment were randomly assigned to two groups of 50 participants each, i.e., group 1 (retainer bonding with XT Primer) and group 2 (retainer bonding with SB). Over two years, examinations were carried out monthly, and detachments were registered by considering the teeth and arches affected. In vitro, no statistically significant differences in SBS and ARI scores were demonstrated between the two groups, both showing a mean bond strength of about 12 MPa and major frequency of ARI “2” (>50% remnant adhesive on the enamel). Conversely, a significantly lower failure rate over 2 years was assessed clinically for group 2 in both arches. Independently of the adhesive and arch, incisors reported a significantly higher failure rate than canines. Scotchbond Universal used in total-etch mode could be a valid alternative to the traditional orthodontic Transbond XT Primer.

Dentin bond strength evaluation between a conventional and universal adhesive using etch-and-rinse strategy

Aim: The aim of this study was to compare the microtensile bond strength (μTBS) and the characteristics of the adhesive interface of Scotchbond Universal - SU – etch-and-rise mode (3M ESPE) and Adper Scotchbond Multi-Purpose - MP (3M ESPE) to dentin over time. Methods: Class I cavity preparations were performed in 60 human molars that were randomly divided according to the dentin bonding system (DBS) used (n=30): (1) Acid conditioning + SU and (2) Acid conditioning + MP. For bonding strength (BS) analysis, 30 teeth (n = 15) were sectioned into sticks and submitted to the microtensile test in a universal testing machine after 24 hours and 12 months. The adhesive interface of the others 30 teeth was analyzed in a confocal microscope after 24 hours and 12 months. The data of μTBS were analyzed by two-way repeated measures ANOVA and Tukey’s HSD (α = 0.05). Results: SU presented the lowest DBS compared to MP (p=0.000). Time did not influenced DBS for both adhesive systems (p=0.177). Confocal microscopy analysis showed no cracks between both adhesive systems tested. Conclusion: The results indicate that MP - μTBS showed a better performance compared to SU in total-etch mode.

Modified Microtensile Bond Strength of Glass Ionomer to Composite Resin Using Universal Adhesive in Self-etch and Total-etch Modes

Background: Glass Ionomer Cements (GICs) are frequently used as base or liner before the application of restorative materials. The success of this approach depends on the bond strength of GICs to composite resin. Objectives: This study to assess the modified microtensile bond strength of glass ionomer to composite resin using universal adhesive in self-etch and total-etch modes. Methods: Samples were fabricated of resin-modified GIC (RMGIC) and conventional GIC(CGIC) (6 x 1 x 1 mm), and were randomly divided into 8 groups. Clearfil SE Bond and G-Premio universal adhesive in self-etch and total-etch modes were used according to the manufacturers’ instructions. Z250 composite was applied over the GIC (12 x 1 x 1 mm), and light-cured. The microtensile bond strength was measured using a universal testing machine. The samples in each group were evaluated under an electron microscope to determine the mode of failure. Data were analyzed using one-way ANOVA and Tukey’s test. Results: The microtensile bond strength of RMGI used with Clearfil SE Bond was significantly higher than that of other groups (6.57±1.15 MPa) (P&lt;0.05). The maximum and minimum microtensile bond strength values of CGIC after applying the bonding agents were recorded after using G-Premio total-etch mode (1.34±0.77 MPa) and SE Bond in total-etch mode(1.18±79 MPa), respectively. Conclusion: Application of of G-Premio in both modes did not show any significant different bond strength in both glass ionomers. The bond strength of RMGIC was higher than that of CGIC, and the maximum bond strength of RMGI was achieved by the use of SE Bond.

Effect of Different Application Techniques of Universal Bonding System on Microtensile Bond Strength of Bulk-Fill Composites to Primary and Permanent Dentin.

Objectives:This study aimed to determine the microtensile bond strength (μTBS) of a bulk-fill composite to permanent and primary coronal dentin using a universal adhesive in self-etch and total-etch modes.Materials and Methods:This in-vitro study was performed on 52 occlusal dentinal surfaces of human primary and permanent teeth. The crowns were cut to the gingival level. The 48 prepared dentin sections were randomly assigned to the following groups (n=13): A: Primary/Total-etch, B: Primary/Self-etch, C: Permanent/Total-etch, and D: Permanent/Self-etch. In groups A and C, after etching for 15 seconds, two layers of a universal bonding (Futurabond U) were applied and cured for 10 seconds. All samples were filled with a bulk-fill composite (x-trafil; VOCO) and cured for 40 seconds. The samples were cut to a bar-shaped dentin block with the dimensions of 1×1×1 mm3, and after 10,000 thermocycles, the μTBS test was accomplished at a crosshead speed of 1 mm/minute. The mean and standard deviation (SD) of μTBS were calculated, and the data were analyzed using two-way analysis of variance (ANOVA) and Fisher’s exact test.Results:The mean μTBS was as follows: A: 15.03±2.0279, B: 11.11±2.4423, C: 23.50±4.8165, and D: 16.26±6.3200 MPa. Futurabond U showed a higher μTBS in the total-etch mode (P<0.001). The permanent teeth had greater μTBS than the primary teeth (P<0.001). Similar percentages of failure modes were observed in the total-etch groups but in the self-etch groups, most failures were in the form of adhesive and mixed.Conclusion:Greater μTBS was observed in the permanent teeth with the total-etch technique.

MICRO SHEAR BOND STRENGTH OF UNIVERSAL DENTAL ADHESIVES TO DENTIN USING DIFFERENT ETCHING MODES (IN VITRO STUDY)

Introduction:Patient demand for tooth colored restorations have made composites an important part of the restorative process. An important factor affecting the intraoral performance of composite restorations is bonding. Therefore, a strong bond at the tooth-restoration interface is necessary for long-term success of a composite restoration. Objectives: To compare the micro shear bond strength of a resin composite (Filtek Z250) to dentin using three universal adhesives in self-etching and total-etching modes and perform fractographic analysis using scanning electron microscope. Materials and methods:60 dentin specimens were used in this study. They were divided into two main groups (self-etch mode & total-etch mode). Each group was subdivided into three subgroups according to the bonding agent used (Tetric N bond universal, All bond universal and Single bond universal). Bonding of adhesives and composite buildups were done according to manufacturer’s instructions. All specimens were thermocycled for 500 cycles from 5 to 55°C. The micro shear bond strength was measured using universal testing machine. Specimens were further sectioned, gold sputtered and evaluated fractographically using scanning electron microscope (SEM). Data obtained were analyzed using F-test (ANOVA), two-way ANOVA and Spearman’s correlation tests. Results: In self-etch mode, the micro shear bond strength of the three tested adhesives didn’t show a significant difference. Meanwhile, etching significantly improved the micro shear bond strength of Single bond universal, while Tetric N bond universal and All bond universal showed no significant difference. Conclusions: An etching step prior to the application of the universal adhesives didn’t significantly affect their micro shear bond strength, except for Single bond universal.

Self-limiting caries excavation with a polymer bur: Adhesive bonding to residual dentin

ObjectivesThe aim of this study was to evaluate the bonding of an universal adhesive to residual affected dentin after polymer bur excavation of natural caries lesions in human teeth. Materials and methodsCaries excavation with a polymer bur and with a carbide bur were compared. A microtensile bond strength (μ-TBS) test was performed in a split-tooth design (n = 20/group). A universal adhesive (Scotchbond Universal, 3M-Deutschland, Neuss/Germany) was applied in either self-etch (SE) or total-etch (TE) mode. Qualitative and quantitative margin analysis was assessed before/after fatigue simulation (n = 8/group). Micro-CT examination was performed before/after polymerization of class-II restorations (Tetric EvoCeram BulkFill, Ivoclar-Vivadent, Schaan/Liechtenstein) (n = 6/group). Volumetric shrinkage and shrinkage vectors were calculated. The internal interface was analyzed under scanning electron microscopy after cutting the teeth. ResultsThe μ-TBS test revealed no significant difference between excavation methods. Mean tensile strengths (MPa) were: polymer-bur/SE = 16.0, polymer-bur/TE = 16.7, carbide-bur/SE = 15.5, carbide-bur/TE = 20.3, dentin/SE = 13.9, dentin/TE = 24.1. Margin analysis rated all groups >99% of perfect margin in dentin and enamel, no influence of excavation methods was found. Micro-CT examination revealed no difference between groups concerning volumetric shrinkage (1.9–2.5%). The shrinkage direction was towards the bonded area. Polymer bur excavation resulted in an irregular surface and thicker smear layer than with carbide bur. ConclusionCaries excavation with a polymer bur does not negatively affect bonding performance to residual affected dentin. Etching with phosphoric acid can further strengthen the interface.

BOND STRENGTH AND MICROMORPHOLOGICAL FEATURES OF DENTIN SUBSTRATES TREATED WITH DIFFERENT ETCHING MODES USING UNIVERSAL ADHESIVE SYSTEM

This in-vitro study assessed bond strength and micromorphological features of dentin substrates treated with different etching modes using universal adhesive system. A total of 28 freshly extracted human molars with coronal dentin caries were used for this study. A total of 80 composite microcylinders with prepared dentin surface containing both sound dentin and carious affected dentin were divided into two main groups (40 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (20 specimens each) according to the type of dentin substrate used: Sound dentin and caries affected dentin. For the Scanning Electron Microscope (SEM) examinations, the teeth were divided into two main groups (8 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (4 specimens each) according to the type of dentin substrate used: sound dentin and caries affected dentin. The interfacial zone was examined using SEM at magnification 5000 X. Data was then recorded, tabulated and statistically analyzed. For sound dentin using total-etch mode (24.02 ± 1.03 MPa) showed statistically significantly lower µSBS than that using self-etch mode (28.04 ± 1.30 MPa) at p<0.05. For caries affected dentin using total-etch mode (18.46 ± 0.86 MPa) showed statistically significantly higher mean µSBS than that using self-etch mode (16.48 ± 0.84 MPa) at p<0.05. Independent of the etch mode used for bonding, sound dentin showed statistically significantly higher mean µSBS than that of caries affected dentin at p<0.05. These results were confirmed by the examination of the SEM images which revealed increase in number and length of resin tags for the groups showing high µSBS. In conclusion, using self-etch universal adhesives on sound dentin is considered to be material dependent. And using total-etch mode of universal adhesive on caries affected dentin can enhance bond strength. Moreover, the type of substrate and etching strategies may affect the bonding performance and durability of restorations in dentistry.