OptiBond XTR Research Articles

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.

Evaluation of antibacterial activity of an experimental dental adhesive containing synthesized quaternary ammonium compound: in vitro study

BackgroundDental adhesives with immobilized antibacterial agents are formulated to combat bacterial invasion along the tooth-restoration interface. This study aims to evaluate the antibacterial effect of synthesized quaternary ammonium compound (QAC) incorporated into commercial dental adhesive.MethodsQAC was synthesized from 2-(Dimethylamino) ethyl methacrylate and 1-Bromobutane and characterized using CHN (Carbon, Hydrogen, Nitrogen), FTIR (Fourier transform infrared) and H+NMR (Proton nuclear magnetic resonance) analyses. The synthesized QAC was assessed for its cytotoxicity and its antibacterial activity against S. mutans using disc diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), time-kill kinetics test, and TEM imaging. The QAC was added to the primer of a commercially available adhesive (OptiBond XTR) at two concentrations; 20 and 40 mg mL−1 representing the MIC and MBC, respectively. The antibacterial properties of the experimental adhesives, commercial antibacterial adhesive Clearfil SE Protect containing 12-methacryloyloxydodecylpyridinium bromide (MDPB), and commercial vehicle (OptiBond XTR) were compared using time-kill kinetics test. Statistical analysis by ANOVA followed by tukey post-hoc test (P < 0.05).ResultsDisc diffusion and time-kill kinetics tests showed potent antibacterial action of QAC, both in the unpolymerized and the cured forms. MIC and MBC were 20 and 40 mg mL−1 respectively. There was no statistically significant difference between experimental adhesives and Clearfil Protect with more than 99% reduction in bacterial count, while OptiBond XTR showed no bacterial killing up for up to 10 h.ConclusionsThe synthesized QAC added to a commercially available adhesive imparted antibacterial properties, thus providing an affordable adhesive system to the local market.

Bond durability of a two-step adhesive with a universal-adhesive-derived primer in different etching modes under different degradation conditions.

This study investigated the enamel and dentin bond durability of a two-step adhesive system, using a universal adhesive-derived primer (G2-Bond Universal [GU]), and compared it with the two conventional, two-step, self-etch adhesive systems (Clearfil SE Bond 2 [CS] and OptiBond XTR [OX]) under thermal cycling (TC) and long-term water storage (WS). The shear bond strengths to bovine enamel and dentin were determined using the etch-and-rinse and self-etch modes. Twelve specimens per test group were prepared and further divided into the following subgroups: 1) subjected to TC, 2) long-term WS, and 3) WS for 24 h (baseline). The enamel and dentin bond durability of GU was superior to those of CS and OX in different etching modes and under different degradation conditions. The latest two-step adhesive system, which utilizes universal adhesives' benefits in its primer, might offer durable clinical bonding performances and can be widely used in a clinical setting.

The Effect of Dentin Contamination by Topical Anesthetics on Micro-Shear Bond Strength: An In Vitro Experiment.

Topical anesthetics are commonly used to minimize pain and anxiety during dental procedures. Research is scarce on the influence of topical anesthetics on bond strength. Thus, this research evaluated the effect of dentin contamination by topical anesthetic solution and gel on the micro-shear bond strengths of etch-and-rinse and self-etch bonding systems. Ninety transversally hemi-sectioned dentin discs were prepared and randomly assigned to three groups: no contamination (control group), contamination with topical anesthetic solution (Xylonor spray, Septodont), and contamination with topical anesthetic gel (Xylonor gel, Septodont). Each contamination group was subdivided into two subgroups (n = 15) based on whether the adhesive system was etch-and-rinse (Optibond Solo Plus, Kerr) or self-etch (Optibond XTR, Kerr). Tygon tubes with resin composite (Filtek Z350 XT, 3M ESPE) were placed on each surface and light cured. After 24 h, a universal testing machine was used to measure micro-shear bond strength (MPa). Furthermore, nine additional specimens of non-contaminated and contaminated dentin were prepared and scanned by a scanning electron microscope. The data of micro-shear bond strength were analyzed using two-way ANOVA, and narrative analysis was used to qualitatively interpret visual data of the micro-morphology of dentin from the scanning electron microscope. No significant differences in micro-shear bond strength among different contamination groups and adhesive systems were found (p &gt; 0.05). The results are supported by micro-morphology of the treated dentin surfaces and modes of failure, as the micro-morphology was similar among contamination and control groups. There was no significant impact of topical anesthetic forms and dentin bonding systems on the micro-shear bond strength, which was supported by the micro-morphology from a scanning electron microscope.

Effect of Different Universal Bonding Agent Procedures on Repair of Feldspathic and Hybrid Ceramics.

To perform application of universal bonding agent based only on the manufacturer's instructions for CAD/CAM-manufactured feldspathic and hybrid ceramics and to investigate the bond strength of the composite resin to these ceramics. A total of 120 samples (2-mm thickness) were obtained from three different CAD/CAM-manufactured ceramics each: a feldspathic ceramic (Vitablocs Mark II), a hybrid ceramic (Cerasmart, GC), and a dual-network ceramic (Vita Enamic). Each of these restorative materials was divided into six subgroups (n = 20 each) in order to apply universal adhesives: All-Bond Universal, Clearfil Quick Universal, Premio Bond, Optibond XTR, Prime&Bond, and Tokuyama Universal Bond. Each bonding agent was applied according to the manufacturer's instructions. Microshear bond strength test was performed at a crosshead speed of 1 mm/min. Two-way analysis of variance (ANOVA) and Tukey post hoc tests were used for statistical analyses. The data suggested a significant impact of bonding agent on all restorative materials applied (P < .001); however, only Prime&Bond demonstrated different effects between materials, with a significant difference between Vitablocs Mark II and Cerasmart restorative materials (P = .001). All universal bonding agents provided an acceptable bond strength for each ceramic. Since different universal bonding agents affected the bond strength between ceramics and composite resin, selecting the most suitable bonding agent for each material will increase the bond strength and clinical success.

Effects of Immediate Coating on Unset Composite with Different Bonding Agents to Surface Hardness.

This study evaluated the surface microhardness of composite, affected by surface coating with different dental adhesive systems. A total of 100 composite discs were divided into five groups. Group 1 was uncoated (control group C), and groups 2 to 5 were coated with different adhesive systems (OptiBond FL: FL, OptiBond SOLO Plus: SOLO, OptiBond XTR: XTR, and OptiBond All in one: AIO, respectively). The Vickers microhardness (VHN) was measured without and with 500 thermocycles. The data were analyzed using two-way ANOVA and Tukey's posthoc test at the 95% confidence level. At 24 hours, the VHN of C (59.96 ± 3.68) and FL (59.83 ± 4.54) were significantly higher than SOLO (51.73 ± 4.63) and AIO (51.45 ± 4.11). The VHN of XTR (54.96 ± 3.68) was not significant compared with that of C and all other groups. After thermocycling, VHN were significantly decreased in all groups. However, there were no significant differences among all groups. At 24 hours, composite coated with different adhesive systems have different effects to VHN. Thermocycling all adhesive resin systems coated on composite surface significantly decreased the VHN.

Adhesive application before hydrofluoric acid etching during repair procedure in dentistry?

Abstract Purpose To evaluate the influence of hydrofluoric acid (HF) contamination on the microtensile bond strength (μTBS) during dental repair procedures before and after application of different dentin adhesives (Optibond FL and Optibond XTR). Materials and methods Thirty-five human molars were ground down into the dentin and were randomly divided into seven groups (G1-G7; n = 5), G1 and G2 being the control groups. Only in the test groups (G3-G7) samples were subjected to HF (9,5%) contamination. Two adhesive systems, Optibond FL (G1, G3, G4, G6) and Optibond XTR (G2, G5, G7) were used. In G3-G5 the adhesive was applied before and after contamination, the test groups G6 and G7 were treated with a single adhesive application after contamination. After composite build-up, samples were stored in water (7 d) and μTBS was determined. Data were evaluated using Wilcoxon test (p Results Control group G2 showed significantly higher μTBS than G1. The HF-contamination did not result in a significant reduction of μTBS. The μTBS of the test groups treated with OptiBond XTR (G5, G7) were significantly higher than the test groups treated with OptiBond FL (G3, G4, G6) following the same procedure. Conclusions HF-contamination of dentin or the adhesive layer does not significantly impair the bond strength, if the adhesive is subsequently re-applied.

Dentin Permeability and Nanoleakage of Universal Adhesives in Etch-and-rinse vs Self-etch Modes.

This study evaluates the reduction in dentin permeability (P) and the expression of nanoleakage in resin-dentin interfaces made with universal adhesives, comparing the self-etch mode of application with the etch-and-rinse mode of application. To measure dentin P at the baseline and after adhesive polymerization, 80 extracted noncarious human third molars (N=80) were sectioned to obtain 0.7-mm-thick midcoronal dentin disks. The specimens were randomly assigned to 8 groups according to the different adhesive systems and application modes used: Scotchbond Universal (SBU; etch-and-rinse [ER] mode vs self-etch [SE] mode), OptiBond XTR (OPT; etch-and-rinse mode vs self-etch mode), Clearfil Universal Bond Quick (CL; etch-and-rinse mode vs self-etch mode), and Adhese Universal (ADH; etch-and-rinse mode vs self-etch mode). A two-way analysis of variance with interaction was used to evaluate the P reduction differences among the groups (α=0.05). Sixteen additional 0.7-mm-thick dentin disks were similarly prepared and treated, immersed in 50 wt% ammoniacal silver nitrate, and then processed according to conventional methods for analysis under transmission electron microscopy. The differences in P reduction among the adhesives were significant (p=0.029). For OPT and ADH (p=0.0304 and p=0.0120, respectively), the P reduction was higher in the ER mode than in the SE mode. For CL and SBU, no differences in P reduction was observed between the two application modes (p>0.05). All the groups showed some pattern of nanoleakage. No adhesive system completely reduced dentin P. Dentin sealing was higher for OPT and ADH in the ER mode, while for SBU and CL, there was no difference between the two modes. All the adhesive systems showed nanoleakage.

Dentin Bond Strength and Microleakage Comparison of Three Different Universal Adhesives

Objectives: The aim of this study is to compare the bond strengths and microleakage values of three different universal adhesive systems applied in self-etch to dentin. Materials and Methods: The study consists of two tests as the bond strength (SBS) test and microleakage test. In the SBS test, the mid-coronal dentin surfaces of forty-five human molars were exposed and randomly assigned into three groups [Single Bond Universal, Optibond XTR, and Tokuyama Universal] and adhesive systems were applied to dentin surfaces. The SBS test was performed after composite build-up. Then, the fracture surfaces were evaluated with a scanning electron microscope (SEM). In the microleakage test, identifical adhesive systems were applied to forty-five human premolars with fasial class V cavities were prepared as in the groups specified in the SBS. After composite resin restoration of cavities, the specimens were thermocycled for 500 cycles and then immersed in basic fuchsine, sectioned, and examined under a stereo-microscope. Data were evaluated using one-way ANOVA, Tukey’s, Chi-square and Mann Whitney U tests. Results: Among the adhesives, the highest bond strength was achieved in Optibond XTR, while Tokuyama Universal showed the lowest (p&amp;lt;0.05). When evaluated for microleakage, no significant difference was reported in occlusal margins. In gingival margins, Optibond XTR showed less leakage compared to Tokuyama Universal (p&amp;lt;0.05). Conclusions: One-step universal adhesive systems did not show bond strength and leakage resistance that was as good as the two-step universal adhesive system.

Interface between calcium silicate cement and adhesive systems according to adhesive families and cement maturation.

ObjectivesThis study aimed to evaluate the interface between a calcium silicate cement (CSC), Biodentine and dental adhesives in terms of sealing ability.Materials and MethodsMicroleakage test: 160 standardized class II cavities were prepared on 80 extracted human molars. The cavities were filled with Biodentine and then divided into 2 experimental groups according to the time of restoration: composite resin obturation 15 minutes after Biodentine handling (D0); restoration after 7 days (D7). Each group was then divided into 8 subgroups (n = 5) according to the adhesive system used: etch-and-rinse adhesive (Prime & Bond); self-etch adhesive 2 steps (Optibond XTR and Clearfil SE Bond); self-etch adhesive 1 step (Xeno III, G-aenial Bond, and Clearfil Tri-S Bond); and universal used as etch-and-rinse or self-etch (ScotchBond Universal ER or SE). After thermocycling, the teeth were immersed in a silver nitrate solution, stained, longitudinally sectioned, and the Biodentine/adhesive percolation was quantified. Scanning electron microscopic observations: Biodentine/adhesive interfaces were observed.ResultsA tendency towards less microleakage was observed when Biodentine was etched (2.47%) and when restorations were done without delay (D0: 4.31%, D7: 6.78%), but this was not significant. The adhesives containing 10-methacryloyloxydecyl dihydrogen phosphate monomer showed the most stable results at both times studied. All Biodentine/adhesive interfaces were homogeneous and regular.ConclusionsThe good sealing of the CSC/adhesive interface is not a function of the system adhesive family used or the cement maturation before restoration. Biodentine can be used as a dentine substitute.

Does Q-MIX pretreatment improve the dentin bond durability of a two-step self-etch adhesive?

This study aims to analyze and assess the effects of three particular dentin pretreatment solutions on the bond durability of a two-step self-etch adhesive (Optibond XTR) applied to dentin after ageing for 2 years. Thirty-five third molars which were extracted (n = 5 for μTBS, n = 2 for nanoleakage) were divided into five groups: Group 1:Control (no pretreatment), Group 2:17% EDTA, Group 3:2% CHX, Group 4:17% EDTA plus 2% CHX, Group 5: Q-Mix. After the pretreatments of dentin, the dentin adhesive was applied as per the guidelines provided by the manufacturer. Half of the specimens were subjected to μTBS tests for 24 hr, while the remaining half were subjected to the tests after being kept for 2 years in water storage. Also, nanoleakage was evaluated with FE-SEM by examining silver nitrate deposits. The data obtained were evaluated using a two-way analysis of variance and Tukey Post Hoc test. The dentin pretreatments did not affect the 24 hr and 2 years μTBS values for OptiBond XTR. At 24 hr, the EDTA + CHX group (50.3 ± 4.9) showed that the highest μTBS value was obtained. Water ageing significantly reduced the μTBS results and after 2 years the highest μTBS value was obtained from the Q-Mix group (37.7 ± 5.2). Different dentin pretreatments do not alter the 24-hr μTBS and were not able to preserve the bond strength after 2 years of ageing. Q-Mix was able to slow down the regression in the strength of the dentin bond as well as nanoleakage over time.

Influence of modeling agents on the surface properties of an esthetic nano-hybrid composite.

ObjectiveThe aim of this study was to evaluate the influence of different modeling agents on the surface microhardness (Vickers hardness number; VHN), roughness (Ra), and color change (ΔE) of a nano-hybrid composite with or without exposure to discoloration by coffee.Materials and MethodsSixty-four cylinder-shaped nano-hybrid composite specimens were prepared using a Teflon mold. The specimens' surfaces were prepared according to the following groups: group 1, no modeling agent; group 2, Modeling Liquid; group 3, a universal adhesive (G-Premio Bond); and group 4, the first step of a 2-step self-adhesive system (OptiBond XTR). Specimens were randomly allocated into 2 groups (n = 8) according to the storage medium (distilled water or coffee). VHN, Ra, and ΔE were measured at 24 hours, 1 week, and 6 weeks. The Kruskal-Wallis test followed by the Bonferroni correction for pairwise comparisons was used for statistical analysis (α = 0.05).ResultsStorage time did not influence the VHN of the nano-hybrid composite in any group (p > 0.05). OptiBond XTR Primer application affected the VHN negatively in all investigated storage medium and time conditions (p < 0.05). Modeling Liquid application yielded improved Ra values for the specimens stored in coffee at each time point (p < 0.05). Modeling Liquid application was associated with the lowest ΔE values in all investigated storage medium and time conditions (p < 0.05).ConclusionDifferent types of modeling agents could affect the surface properties and discoloration of nano-hybrid composites.

Effect of thermo-cycling on micro-tensile bond strength of bulkfill resin composite using recent universal adhesive

Statement of the problem: bonding performance of newly launched universal adhesive recommended by the manufacturer to be used with sonically activated bulkfill resin composite need further investigation. Materials and Methods: A total of 40 non carious human molar teeth were extracted and collected from diabetic patients for this study. The selected teeth were divided into two main groups, 20 teeth each, according to adhesive used (A). In group (A1), the adhesive system was universal one step self- etch adhesive (OptiBond Universal), while in group (A2), two steps universal self etch primer adhesive (OptiBond XTR) was applied. Each group was subdivided into two subgroups, 10 teeth each, according to whether thermocycling was carried out or not (T). Where (T0) class denotes the teeth that were not subjected to thermocycling and (T1) class denotes the teeth that were subjected to thermocycling. (SonicFill 2 bulkfill resin composite) restorative material was used with both adhesives. The teeth stored in distilled water for 24 hours before the rod specimens were prepared for the microtensile bond strength test. Two rods from each tooth were obtained. Half of the specimens of each group were subjected to theromcycling testing at 5oC± 2oC to 55oC± 2oC for 500 cycles. Microtensile bond strength test was carried out using a universal testing machine. Results: showed that the mean microtensile bond strength of one step universal self-etch adhesive (OptiBond Universal) had statistically significantly higher value than the self-etch primer (OptiBond XTR) either with thermocycling or without thermocycling at (P <0.001). The mean microtensile bond strength of one step universal self etch adhesive had statistically significantly higher value without thermocycling than with thermocycling at (P <0.001). The microtensile bond strength test with the two steps universal self-etch primer (OptiBond XTR) adhesive showed that there was no statistically significant difference between mean microtensile bond strength either with or without thermocycling (P = 0.067). Conclusion: The (SonicFill2) resin composite one of the recently used bulkfill resin composite restorative material performed higher bond strength with one step universal self etch adhesive more than with two steps universal self-etch primer adhesive when applied to the dentin substrate. However concerning bond stability, the SonicFill2 resin composite restorative material showed higher bond stability after thermocycling with two steps universal self etch primer more than with one step universal self etch adhesive.

Influence of solvent evaporation on ultimate tensile strength of contemporary dental adhesives

The aim of this study was to evaluate the influence of solvent evaporation on the ultimate tensile strength (UTS) of commercial adhesives. Two 1-step (OptiBond All-In-One and G-Premio Bond) and two 2-step (Clearfil SE Protect, OptiBond XTR) adhesives were selected. Two bottles of each adhesive were opened and stored at 37 °C in a dry oven with silica gel shielded from light for 2 weeks (“Desiccated”). Two unopened bottles were stored at room temperature (“Original”). After 2 weeks, the adhesives were used to fill an hour-glass shaped, metallic matrix mold and light-cured. Samples were weighed, and then immersed in a 37 °C water bath for 1 h or 7 days. The UTS of each sample was then measured at a cross-head speed of 1 mm/min (n = 10). The UTS for the Clearfil SE Protect was higher in the “Original” than “Desiccated” samples (p < 0.05). For the OptiBond XTR, no significant difference was found between the ‘Original’ and ‘Desiccated’ samples (p > 0.05). Neither of the two “Original” 1-step samples could be hardened, even after light-curing, yet the ‘Desiccated’ OptiBond All-In-One samples obtained high UTS values. Both OptiBond All-In-One and Clearfil SE Protect had an increase in weight after the 7-day immersion in water. In conclusion, residual solvent reduces the mechanical strength of the adhesive. The hydrophilicity of the adhesive resin might also affect its mechanical strength.

The role of spatial frequency analysis in correlating atomic force microscopy and optical profilometry with self-etch adhesive enamel bond fatigue durability.

The purpose of this study was to: (a) evaluate the role of enamel surface roughness on bond fatigue durability and (b) evaluate statistical differences in roughness values based on measurement technique, including the use of spatial filtering for optical profilometry (OP). OptiBond XTR (Kerr Corp), Prime & Bond elect (DENTSPLY Caulk), Scotchbond Universal (3 M Oral Care), and XTR pre-etched with Ultra-Etch phosphoric acid (35%) (Ultradent) self-etch adhesives were used to treat enamel. A flat ground enamel surface was included as a control. Atomic force microscopy (AFM) and OP were used to measure the surface topography of each enamel surface following the application of adhesives. AFM, OP, and filtered OP (FOP) roughness values, where FOP was designed to only include the lateral spatial resolution consistent with AFM roughness values, were collected. Spatial resolution filtering with OriginPro was used to compare line scans from the two imaging techniques and generate the FOP group. These micro- versus nanoscale lateral roughness values were correlated with shear bond and shear fatigue strengths of the adhesives bonded to enamel. Roughness values showed differences based on measurement technique and strong correlations with bond and fatigue strength. The filtered OP group demonstrated the importance of careful usage and reporting of atomic force microscopy and OP metrics in adhesive dentistry. Best practices for surface roughness analysis were also discussed.

Do ozonated water and boric acid affect the bond strength to dentin in different adhesive systems?

The aim of this in vitro study was to compare the effects of the application of three different cavity disinfecting agents to dentin on the micro-shear bond strength (μ-SBS) of one self-etch and two universal adhesive systems. In total, 120 caries-free human permanent molar teeth were used in this study. Mid-coronal dentin surfaces were revealed by cutting occlusal enamel and a standard smear layer was obtained by using 600-800-1200 grid silicon carbide abrasive papers. Specimens were randomly assigned to four groups according to the disinfectant used: Group 1: Control (no disinfectant); Group 2: 2% chlorhexidine based (Consepsis); Group 3: 10 ppm ozonated water (TeknO3zone); Group 4: 5% boric acid (Handmade). Each group was divided into three subgroups according to the type of adhesive (Clearfil SE Bond, OptiBond XTR, and Tokuyama Universal). Specimens were bonded using either Clearfil SE Bond, OptiBond XTR or Tokuyama Universal, which were employed according to the manufacturer's instructions. Resin composite microcylinders were bonded using Tygon® tubes for μ-SBS testing. After specimens were stored for 24 h, at 37°C in distilled water, μ-SBS test was measured with a universal test machine (LF Plus, Lloyd, Instrument). μ-SBS results were analyzed by one-way analysis of variance (ANOVA) and Tukey's tests. When the mean microshear bond strength values of the control group were compared, the difference between the subgroups was not significant (P < 0.05). When the mean microshear bond strength values of the chx, ozonated water, and boric acid were compared, the difference between Clearfil SE Bond and Tokuyama Universal was significant (P < 0.05) and the difference between the other groups was not significant (P > 0.05). Ozonated water and boric acid may be as an alternative to other materials used as cavity disinfectants.

Universal Adhesives Benefit from an Extra Hydrophobic Adhesive Layer When Light Cured Beforehand.

To measure microtensile bond strength (μTBS) of universal adhesives immediately and after 6-month aging, with or without an additional adhesive layer applied on a separately light-cured or non-light-cured universal adhesive. Eighty human third molars were randomly assigned to 8 experimental groups. The universal adhesives Clearfil Universal Bond (Kuraray Noritake) and Single Bond Universal (3M Oral Care) were used in self-etch mode (following the manufacturer's directions), and either light cured or not before application of an extra hydrophobic adhesive layer (Clearfil SE Bond bond, Kuraray Noritake). The two-step self-etch adhesives Clearfil SE Bond (Kuraray Noritake) and OptiBond XTR (Kerr) were used as references. After composite buildups were bonded to mid-coronal occlusal dentin surfaces, the specimens were stored in water (37°C/24 h) and sectioned into microspecimens (0.96 ± 0.04 mm2). Half of the specimens were immediately subjected to μTBS testing (1.0 mm/min), while the other half was stored in water (37°C) for 6 months prior to testing. Failure analysis was performed using stereomicroscopy and SEM. Data were analyzed with two-way repeated measures ANOVA, Tukey's and paired t-tests (p = 0.05). The immediate μTBS was similar for the universal adhesives when applied following the different application strategies (p > 0.05). Application of an extra layer of hydrophobic adhesive improved the aged μTBS of the universal adhesives, which was statistically significant when the universal adhesives were first light cured (p < 0.05). The reference adhesives Clearfil SE Bond and OptiBond XTR exhibited a significantly higher immediate and aged μTBS to dentin than did the universal adhesives (p < 0.05). The bond durability of universal adhesives, applied in self-etch mode, was found to benefit from the application of an extra hydrophobic adhesive layer when the universal adhesives were first light cured.

In vitro Comparative Study on the Marginal Adaptation of Direct, Semi-direct and Indirect Composite Resins Restorations to Dentine and Dental Cementum

The aim of the present study is to compare the marginal adaptation of direct, semi-direct and indirect restorations made with nanofill and microhybrid composite materials and ormocers materials bonded with SE adhesives at the dentin and cementum. 120 standardized class II cavities were prepared (40 for each techniques- RD, RSD, RI) with the gingival margin over and below to the cementum-enamel junction. The teeth (n= 20) were restored using one of three adhesive systems (OptiBond XTR, G-Premio Bond bottle refill, Futurabond U) with incrementally placed composite restorations and ormocers. After applying the various restorations, the teeth were prepared for SEM analysis to check the marginal adaptation by the presence of continuous margins or gaps. Comparative analysis of treatment methods and materials used was performed by statistical analysis of Chi-square test data, the statistical significance was p [0.05 and Fisher�s Exact Test for validation of results. It was found that among the three materials used for RD, RSD, RI both at the dentin and the cementum, there are no significant differences (RD d = 0.661, RSD/d = 0.755, RSD/c = 0.942; RI/d = 0.739; RI/c = 0.985). Comparison between the presence of continuous margins/gaps subgingivally and supragingivally at the three types of restorations shows that there are significant differences between the marginal adaptation at the cementum and dentin to all the restoration techniques used (p [0.05). Direct and indirect restorations with nanocomposites and ormocers bonded with 1-step SE adhesive are the best solutions for restoring the posterior teeth.

Analysis of pre-test failures and bond-strengths of seven adhesive systems to bovine dentine: A nine-year novice/beginner operator study

ObjectiveThe aims were to evaluate, via multi-year student cohorts: (i) the incidence of pre-test failures and (ii) shear bond strengths of single- and multi-step adhesives to bovine dentin. MethodsThe experiments were performed by cohorts of dental students (2008–2016). Each year the bond strengths of three dental adhesives to bovine dentin were tested. Four self-etching adhesives (Optibond-All-in-One, [OBAIO]; Optibond XTR [OBXTR]); Xeno V [XV]; Xeno V+ [XV+]; a three-step etch-and-rinse-system (Optibond FL, [OBFL]), a self-etch universal adhesive (Scotchbond Universal [SBU]) and a self-etch/etch-and-rinse adhesive (Xeno Select, [XS]) were included in the study. Composite-cylinders were bonded perpendicularly to prepared bovine dentin surfaces. Shear-tests were performed with a universal-testing-machine. ResultsBoth overall, and within years, XV and XV+ showed significantly (p<0.01) higher percentages of pre-test failures versus other adhesive systems tested in the period 2008–2014 (OAIO, OBFL, OBXTR). Fewest pre-test failures were observed for OBFL, OBXTR and SBU. Trends in mean bond strengths and Weibull distributions were noted, per adhesive, with trends in the incidence of pre-test failures. Pre-test-failures and bond strengths depended on the air-drying technique. The adhesive systems showed variable technique sensitivity.Multistep bonding systems (Optibond FL and Optibond XTR) showed minimal pre-test failures and high bond strength applied by relatively inexperienced operators and irrespective of the applied air-drying technique. However, two single-step adhesives (OAIO and SBU) showed comparable results to the multi-step systems. SignificanceThe clinical need for rapid application dentine adhesives can result in varied outcomes with relatively inexperienced operators. These outcomes include both the incidence of pre-test failures as well as the distributions of shear bond strengths achieved, although these measures appear to be related. However, both outcomes are dependent upon the adhesive products utilised and especially upon the applied air pressure (flow rate). Some rapid application systems appear to perform comparably with well-established multi-step adhesives.

Microtensile bond strengths of adhesively bonded polymer-based CAD/CAM materials to dentin.

This in vitro study aimed to evaluate the effect of two different polymer-based CAD/CAM materials; resin-nano ceramic (Lava Ultimate [LVU]) and composite (CERASMART [CS]), their different surface pre-treatments, and use of different resin cements on the µTBS of adhesively bonded CAD/CAM onlays to dentin. CAD/CAM materials were cut into slabs and divided into five groups according to the surface pre-treatments applied: Silane Primer, OptiBond XTR adhesive, Silane Primer+OptiBond XTR adhesive, Single Bond Universal (SBU), and RelyX Ceramic Primer+SBU. The LVU and CS specimens were bonded to the mid-coronal dentin of 50 non-carious human molars using NX3 resin cement with OptiBond XTR or RelyX Ultimate with SBU. µTBS was evaluated after 5,000 thermocycling and analysed with three-way-ANOVA and post-hoc Tukey's tests (p<0.05). The µTBS was significantly influenced by the type of CAD/CAM material (p<0.0001) surface pre-treatments (p<0.05) and resin cements (p<0.05). Regardless of the pre-treatments and resin cements, bonding of the composite CAD/CAM material to dentin was higher than the resin nano-ceramic material.