Optibond Solo Plus Research Articles

Resin composites: strength of the bond to dentin versus mechanical properties

This study (1) investigated whether the combination of an adhesive system from one manufacturer with a resin composite from the same manufacturer provides superior bonding of the resin composite to dentin compared with the combination of an adhesive system from one manufacturer with a resin composite from another manufacturer, and (2) tested for a possible influence on bond strength of mechanical properties of the resin composite. After application of an adhesive system, a resin composite was bonded to flattened human dentin and tested in shear after 1 week. Five adhesive systems (AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, Optibond Solo Plus, and Xeno III) were tested with each of five resin composites (Tetric Ceram, Filtek Supreme, Clearfil AP-X, Premise, and EsthetX). The mechanical properties flexural strength and flexural modulus were determined by three-point loading. Bond strengths were influenced by the brand of adhesive system (P < 0.0001) and by the brand of resin composite (P < 0.0001), but the combination of an adhesive system from one manufacturer with a resin composite from the same manufacturer did not provide bond strengths that were superior to those obtained when an adhesive system from one manufacturer was combined with a resin composite from another manufacturer. Independent of the brand of resin composite, the adhesive system Clearfil SE Bond mediated the highest bond strength to dentin. For each adhesive system, the resin composite Clearfil AP-X resulted in the highest bond strength to dentin. Significant positive correlations were found between bond strength and flexural strength (P < 0.0026, r = 0.21) and between bond strength and flexural modulus (P < 0.0017, r = 0.22).

Influence of adhesive systems and flowable composite lining on bond strength of class II restorations submitted to thermal and mechanical stresses

The purpose of this study was to evaluate the effect of adhesive systems and flowable composite lining on bond strength to gingival margins of Class II restorations after thermal/mechanical stresses. Proximal cavities were prepared in 90 bovine incisors. Teeth were assigned into nine groups (n = 10), according to the combination of bonding agent [Single Bond (SB), Optibond Solo Plus (OP), Prime & Bond NT (NT)] and layer (1 mm) of flowable composite Filtek Flow (FF) [absent, one layer, two layers]. Materials were applied according to manufacturers' instructions, and FF layers were photoactivated separately. Restorations were concluded with composite resin and were submitted to thermal (1000x, 5-55 degrees C) and mechanical stresses (100,000x, 80 N). For microtensile evaluation, slabs from the gingival bonded interface were obtained, tested under tension, and their failure mode was observed by scanning electron microscopy. Bond strength data were analyzed using two-way ANOVA/Tukey's test. No interaction was observed between adhesive systems and FF lining (p = 0.89). Also, no significant difference was found between bond strength values, whether or not FF layers were used (p = 0.33). However, bonding systems demonstrated significant differences (p = 0.01). SB and NT presented means higher than those observed with OP. Fracture modes varied considerably between experimental groups, and a greater frequency of cohesive failures was noted when FF layers were used.

A comparison of fatigue crack growth in resin composite, dentin and the interface

Objectives The objective of this in vitro study was to evaluate the fatigue crack growth properties of the dentin/resin adhesive interface. Methods Compact tension (CT) specimens were prepared from coronal dentin, resin composite, and dentin bonded to resin composite using Optibond Solo Plus adhesive. All specimens were then subjected to cyclic Mode I loading while fully hydrated at a stress ratio of R = 0.1 and frequency of 5 Hz. Steady state fatigue crack growth was modeled using the Paris Law in terms of the exponent ( m) and coefficient ( C). Results The average fatigue crack growth rates in the resin composite ranged from 1.6E−06 to 3.8E–05 mm/cycle with growth occurring over a stress intensity range from 0.40 to 0.77 MPa m 1/2; the average growth exponent was 6.9 ± 3.1. Average fatigue crack growth rates for the dentin/resin interface specimens ranged from 5.5E−07 to 6.4E−03 mm/cycle with growth occurring over a stress intensity range from 0.37 to 0.64 MPa m 1/2. The Paris Law exponent for these specimens ranged from 16 ≤ m ≤ 25. Fatigue crack growth at the interface occurred primarily in the adhesive resin and at the adhesive–dentin interface. In addition, many of the dentin/resin specimens underwent unstable fracture at a comparatively low stress intensity range without undergoing cyclic crack growth. Significance The dentin/resin adhesive interface proved to be significantly more sensitive to fatigue crack growth than either dentin or resin composite. Variation in the cyclic crack growth responses of the dentin/resin interface specimens suggests that the interface, and particularly the adhesive resin, exhibits lower resistance to crack initiation and growth in comparison to dentin.

Bonding of composite to water aged composite with surface treatments

Objective The purpose of this study was to determine the shear bond strength of new composite to water aged composite with and without interfacial surface treatment. Methods Two hundred and eighty cylindrical samples were prepared for each of three resin composites (Spectrum, Dentsply; Durafill, Kulzer; Herculite, Kerr). Seventy samples of each material were bonded immediately and the remaining were stored in water. After 1, 4 and 12 weeks 70 samples were removed and the surface treated prior to bonding a second fresh increment. The treatments were: (1) no treatment, (2) abrasion with pumice, (3) a layer of Prime and Bond (Dentsply), (4) abrasion + Prime and Bond, (5) a layer of Optibond Solo Plus (Kerr), (6) abrasion + Optibond and (7) a layer of bis-GMA/TEGDMA. The specimens were loaded to failure in shear mode with a crosshead speed of 50 mm/min until fracture. The fracture surface of a number of specimens were examined in a scanning electron microscope. Results At all time intervals the treatment that resulted in the highest bond strengths (>20 MPa) was treatment with the dentine bonding agents (DBS) Prime and Bond or Optibond Solobond Plus. No treatment or abrasion alone resulted in very low bond strengths even after 1 week in water. When used in conjunction with DBS's abrasion did not increase the bond strength over the use of the DBS alone. The bis-GMA/TEGDMA was not as effective as the DBS's. Significance When bonding new composite to composite that has been underwater it is essential to treat the original composite surface. The results of this study indicated that the application of a dentine bonding agent significantly enhanced the bond. Abrasion alone did not produce an adequate bond.

Resin adhesion to caries‐affected dentine after different removal methods

Caries-affected dentine is the common bonding substrate when treating a patient. At present, there are many methods used for caries removal. The aim of this study was to evaluate the microtensile bond strength of two adhesives (Clearfil Protect Bond and OptiBond Solo Plus Total-Etch) to caries-affected dentine after three different caries removal methods. Extracted carious human third molars were used and caries-affected dentine surfaces were obtained from one of the three removal methods: (i) round steel bur in a slow-speed handpiece; (ii) Er:YAG laser; or (iii) 600-grit silicon carbide abrasive paper. Each of the adhesives was used to bond resin composite to the caries-affected dentine according to the manufacturers' instructions. Hourglass-shaped specimens were prepared and stressed in tension at 1mm/min. Data were analysed using two-way analysis of variance and least significant difference test. Clearfil Protect Bond showed significantly lower bond strength than OptiBond Solo Plus Total-Etch after caries removal with round steel bur, but the opposite was found for specimens treated with silicon carbide abrasive paper. For laser-treated dentine, no significant differences between the adhesives were revealed. Besides the differences in adhesives, different caries removal methods seem to influence resin adhesion to caries-affected dentine.

Adhesive systems and secondary caries formation: Assessment of dentin bond strength, caries lesions depth and fluoride release

Objectives The present study evaluated the microtensile bond strength and caries formation on adhesive/dentin interfaces before and after dynamic chemical formation of secondary caries. Methods Restorations were prepared on the dentin surface of 80 bovine incisors using four adhesive systems: two fluoride-free (Single Bond and Clearfil SE Bond) and two fluoride containing (Optibond Solo Plus and Clearfil Protect Bond). The restored teeth were then sectioned into multiple slabs that were further trimmed at the bonded interface to a cross-sectional area of 1 mm 2. Half of the slabs were subjected to secondary caries formation using a pH cycling model (treated groups); while the other half was used as the control group (no pH cycling). The specimens designated for bond strength evaluation were subjected to microtensile bond strength test (μTBS). Caries lesions formation was assesses by polarized light microscopy at different depths from the adhesive–dentin bonded interface. The fluoride ion concentration was evaluated using the de/remineralization solutions (De/Re). Results No differences in μTBS were observed among the adhesive systems in both the control and treated conditions. Secondary caries significantly reduced the values of μTBS for all adhesives ( p < 0.05). Optibond Solo Plus presented the lowest caries formation at 5 μm depth. Fluoride concentrations present in the De/Re were less than 0.03 ppm, regardless of the adhesive system tested. Significance Bond strength values significantly decreased after in vitro secondary caries formation. Fluoride present in adhesive systems is not capable of inhibiting secondary caries or maintaining bond strength values following caries formation.

Genotoxicity evaluation of five different dentin bonding agents by chromosomal aberration analysis

Dentin bonding agents became unavoidable in today's aesthetic restorative dentistry. Nevertheless, more and more evidences on their possible cytotoxicity and/or genotoxicity emerge. Still, only limited number of studies has been published on that issue. In our work we evaluated possible genotoxicity of five different adhesives: Adper Single Bond, Adper Single Bond 2 with nanofiller, Excite, OptiBond Solo Plus and Prompt L-pop. Genotoxicity assessment was carried out on human lymphocytes in vitro, using chromosomal aberration analysis. Polymerized adhesives were tested at three different dilutions of the 0.5 g mL(-1) eluate stock (2.5 x 1:10(6), 1:10(6) and 1:10(5)) after 1 h, 24 h and 5 days of elution. Slight but significant increase in the number of chromatid breaks was observed after 24-h elution period, for adhesives Adper Single Bond 2, Excite, and OptiBond Solo Plus at dilutions of 1:10(6) and 1:10(5), and for other two only at dilution of 1:10(5). First three adhesives also appeared to be slightly genotoxic after 1 h of elution but only at 1:10(5). As a bonding agent remains in close contact with living dental tissue over a long period of time, information on their possible genotoxicity and carcinogenicity should be more clearly clarified in the near future.

A statistical evaluation of microtensile bond strength methodology for dental adhesives

Objectives The purpose of this study was to determine the correlation between beams from the same tooth in a microtensile bond strength study and to examine their effect on the interpretation of results. Methods A flat occlusal dentin surface was exposed using wet 180, 240, and 320-grit SiC paper on caries-free human molar teeth. Adhesive was applied followed by 6 mm of composite (CoreRestore2) applied in 2 mm increments. Four adhesives were used: Optibond FL, light-cure, dual-cure, and self-cure Optibond Solo Plus. Nine beams (1 mm 2) were obtained from fifteen teeth for each group, labeled to indicate the orientation of the beams to each other and stored in artificial saliva at 37 °C for 1 week or 3 months. Microtensile dentin bond strengths were determined using a non-trimming technique. Statistical comparisons between adhesive-storage combinations were performed using ANOVA. Analyses were performed assuming statistical independence between all beams and then repeated using a random tooth effect to account for correlations between beams from the same tooth. Results Significant correlations were found between beams. No pattern was observed in the correlations related to the orientations of the beams to each other. Conclusions regarding statistical significance of comparisons (at alpha = 0.05) were sometimes affected by the incorrect assumption of independent beams. The degree of correlation was large enough to severely affect power and sample size calculations. Significance Analyses of microtensile dentin bond strength studies need to account for correlations between beams to avoid over-stating statistical significance of study results.

Bonding effectiveness of adhesive luting agents to enamel and dentin

Objectives The bonding effectiveness of five adhesive luting agents to enamel and dentin using different application procedures was determined using a micro-tensile bond strength protocol (μTBS). Methods Enamel/dentin surfaces of human third molars were flattened using a high-speed diamond bur. Composite resin blocks (Paradigm, 3 M ESPE) were luted using either Linkmax (LM; GC), Nexus 2 (NX; Kerr), Panavia F (PN; Kuraray), RelyX Unicem (UN; 3M ESPE) or Variolink II (VL; Ivoclar-Vivadent), strictly following manufacturers’ instructions. For some luting agents, modified application procedures were also tested, resulting in four other experimental groups: Prompt L-Pop + RelyX Unicem (PLP + UN; 3 M ESPE), Scotchbond Etchant + RelyX Unicem (SE + UN; 3 M ESPE), Optibond Solo Plus Activator + Nexus 2 (ACT + NX; Kerr) and K-Etchant gel + Panavia-F (KE + P; Kuraray). The experimental groups were classified according to the adhesive approach in self-adhesive (UN), etch-and-rinse (ACT + NX, NX, KE + P, SE + UN and VL when bonded to enamel) and self-etch adhesive luting agents (LM, PLP + UN, PN and VL when bonded to dentin). The specimens were stored for 24 h in distilled water at 37 °C prior to μTBS testing. The Kruskal–Wallis test was used to determine pairwise statistical differences ( p < 0.05) in μTBS between the experimental groups. Results When bonded to enamel, ACT + NX (15 MPa) and UN (19.6 MPa) scored significantly lower than VL (49.3 MPa), LM (49.2 MPa), PN (35.4 MPa) and SE + UN (35.2 MPa), while PLP + UN (23.5 MPa) showed a significantly lower μTBS than VL (49.3 MPa) and LM (49.2 MPa). No significant differences were noticed between VL (49.3 MPa), LM (49.2 MPa), NX (37.9 MPa), KE + PN (38.8 MPa), PN (35.4 MPa) and SE + UN (35.2 MPa). Regarding the bonding effectiveness to dentin, all luting agents bonded equally effectively (UN: 15.9 MPa; LM: 15.4 MPa; PN: 17.5 MPa; NX: 22.3 MPa), except VL (1.1 MPa), SE + UN (5.9 MPa) and ACT + NX (13.2 MPa). VL revealed an exceptionally high number of pre-testing failures, most likely due to a combined effect of not having cured the adhesive separately and an insufficiently light-cured luting agent. Significance Following a correct application procedure, the etch-and-rinse, self-etch and self-adhesive luting agents are equally effective in bonding to enamel and dentin. Several factors negatively influenced bond strength such as bonding RelyX Unicem to enamel without prior phosphoric acid etching; no separate light-curing of a light-polymerizable adhesive prior to cementation, use of a light-polymerizing adhesive converted into a dual-polymerizing adhesive, and use of a dual-cure luting agent with a low auto-polymerizable potential.

Shear bond strength of acetone-based one-bottle adhesive systems

The aim of this study was to assess the shear bond strength of four acetone-based one-bottle adhesive systems to enamel and dentin, and compare to that of an ethanol-based system used as control. Fifty human molars were bisected mesiodistally and the buccal and lingual surfaces were embedded in acrylic resin using PVC cylinders. The buccal surfaces were ground to obtain flat dentin surfaces, while the lingual surfaces were ground to obtain flat enamel surfaces. All specimens were polished up to 600-grit sandpapers and randomly assigned to 5 groups (n=20; 10 dentin specimens and 10 enamel specimens), according to the adhesive system used: One-Step (Bisco); Gluma One Bond (Heraeus Kulzer); Solobond M (Voco); TenureQuik w/F (Den-Mat) and OptiBond Solo Plus (Kerr) (control). Each adhesive system was applied according to the manufacturers' instructions. The respective proprietary hybrid composite was applied in a gelatin capsule (d=4.3 mm) and light-cured for 40 s. The specimens were tested in shear strength with an Instron machine at a crosshead speed of 5 mm/min. Bond strengths means were analyzed statistically by one-way ANOVA and Duncan's post-hoc (p< or =0.05). Shear bond strength means (MPa) (+/-SD) to enamel and dentin were: Enamel: One-Step=11.3(+/-4.9); Gluma One Bond=16.3(+/-10.1); Solobond M=18.9(+/-4.5); TenureQuik w/F=18.7(+/-4.5) and OptiBond Solo Plus=16.4(+/-3.9); Dentin: One-Step=6.4(+/-2.8); Gluma One Bond=3.0(+/-3.4); Solobond M=10.6(+/-4.9); TenureQuik w/F=7.8(+/-3.9) and OptiBond Solo Plus=15.1(+/-8.9). In enamel, the adhesive systems had statistically similar bond strengths to each other (p>0.05). However, the ethanol-based system (OptiBond Solo Plus) showed significantly higher bond strength to dentin than the acetone-based systems (p< or =0.0001). In conclusion, the solvent type (acetone or ethanol) had no influence on enamel bond strength, but had great influence on dentin bonding, which should be taken into account when choosing the adhesive system.

Shear Bond Strengths of Self-etching Adhesives to Caries-affected Dentin on the Gingival Wall

The purpose of this study was to evaluate the bonding ability of five current self-etching adhesives to caries-affected dentin on the gingival wall. Seventy extracted human molars with approximal dentin caries were employed in this study. In order to obtain caries-affected dentin on the gingival wall, grinding was performed under running water. Following which, specimens mounted in acrylic blocks and composite resins of the bonding systems were bonded to dentin with plastic rings and then debonded by shear bond strength. With Clearfil SE Bond, bonding to caries-affected dentin showed the highest bond strength. With Optibond Solo Plus Self-Etch, bonding to caries-affected dentin showed higher shear bond strength than AQ Bond, Tyrian SPE & One-Step Plus, and Prompt-L-Pop (p<0.05). Further, the bond strengths of Clearfil SE Bond and Optibond Solo Plus Self-Etch to sound dentin were higher than those of Prompt-L-Pop, AQ Bond, and Tyrian SPE & One-Step Plus (p<0.05). In conclusion, besides micromechanical interlocking through hybrid layer formation, bond strength of self-etch adhesives to dentin may be increased from additional chemical interaction between the functional monomer and residual hydroxyapatite. The results of this study confirmed that differences in bond strength among self-etching adhesives to both caries-affected and sound dentin were due to chemical composition rather than acidity.

Influence of interface surface conditions on indentation failure of simulated bonded ceramic onlays

This study aims to evaluate the influence of surface roughness and acid etching on interfacial failure load and fracture initiation site for simulated resin bonded ceramic restorations. Layered disks were fabricated using soda lime glass to simulate porcelain and fiberglass to represent dentin. These materials were selected due to their approximate elastic modulus to porcelain or dentin. In addition, soda lime glass allowed for visualization of crack initiation. Glass microscope slides (1.2 mm thick) were sectioned into 1-mm2 specimens. The frosted portions of the slides were used as the rough or sandblasted group and the clear areas were used as the smooth or polished group. All surfaces were either cleaned or etched. Prepared surfaces were divided into eight groups and bonded to the substrates using Optibond Solo Plus (SDS Kerr, Orange, CA) and Nexus resin cement (SDS Kerr). Support substrates were made from 5-mm slices of fiberglass rods (1/2 in. diameter). Vertical loads were applied to the layered disks with a 20-mm spherical indenter at a cross-head speed of 0.05 mm/min. Observations were made using 10x magnification with a video monitor. Load magnitudes were recorded at the time of crack initiation. Weibull parametric survival analysis and the effect likelihood ratio test were performed on the failure initiation load data to determine significant differences at the 0.05 level. Mean failure initiation loads ranged from 273.6 to 341.9N for the rough specimens and from 1056.5 to 2980.2N for the smooth samples. According to the Weibull parametric survival analysis and the effect likelihood ratio test, surface roughness and surface etch significantly influenced failure initiation loads. Smoother surfaces tolerated much greater contact loads before failure initiation. The clinical performance of all-ceramic restorations may be improved with smoother internal surfaces. Etching significantly increases survival for restorations with smooth internal surfaces.

Incompatibility of Oxalate Desensitizers with Acidic, Fluoride-containing Total-etch Adhesives

The use of oxalate desensitizers on acid-etched dentin prior to adhesive application can result in subsurface tubular occlusion by calcium oxalate crystals. However, the solubility of calcium oxalate increases in acidic solution. We hypothesized that total-etch adhesives can, depending upon their pH, interact with oxalate-desensitizer-treated dentin in an adverse manner. Acid-etched human dentin treated with 2 oxalate desensitizers (BisBlock and Super Seal) was bonded with 4 simplified total-etch adhesives: One-Step (OS), Single Bond (SB), OptiBond Solo Plus (OB), and Prime&Bond NT (PB). Composite-dentin beams were examined by SEM and TEM, both of which revealed numerous spherical globules on OB- and PB-bonded, desensitizer-treated dentin, but not in OS or SB samples. Bond strengths produced by OB and PB were significantly lower in oxalate-treated specimens than those produced by OS or SB. These surface globules may have interfered with hybridization of demineralized dentin with OB and PB resins and caused compromised bond strengths.

Bond strengths of eight contemporary adhesives to enamel and to dentine: an in vitro study on bovine primary teeth

The aim of this study was to compare the shear and tensile bond strengths of eight adhesive systems to the enamel and dentine of primary bovine teeth. Two hundred and fifty-six noncarious bovine mandibular primary incisors were collected and stored in an aqueous 1% chloramine solution at room temperature for no longer than 3 months after extraction. The tested adhesives were: Clearfil SE bond (SE); Adper Prompt L Pop (LP); Optibond Solo Plus Self-etch (OB); AdheSE (AS); Xeno III (XE); Scotch Bond 1 (SB); Etch & Prime 3.0 (EP); and I Bond (IB). For the shear bonding test and the tensile bonding test, the labial surfaces of primary incisors were used. To obtain a flat surface, the labial surfaces of the teeth were sanded on wet silicon carbide paper, first with number 200 grit for 20 s and then with number 600 grit for 60 s (n = 128; 64 for shear bonding and 64 for tensile bonding). The results were compared with an analysis of variance and Bonferroni's multiple comparison test. Shear bond strength values ranged from 18.1 to 8.9 MPa on enamel (in decreasing order, SE, LP, OB, AS, XE, SB, EP and IB), and from 17.8 to 8.2 MPa on dentine (in decreasing order, SE, SB, OB, AS, XE, LP, IB and EP). Tensile bond strength values ranged from 13.1 to 6.7 MPa on enamel (in decreasing order, SE, OB, AS, LP, XE, IB, SB and EP), and from 12.1 to 5.7 MPa on dentine (in deceasing order, SE, SB, OB, AS, XE, LP, IB and EP). The differences in bond strengths between the eight systems on enamel and dentine were all statistically significant. This was true for both the shear and tensile bond strengths. The highest shear bond strength was achieved by SE on enamel and dentine, and the lowest by IB on enamel and EP on dentine. The highest tensile bond strength was obtained by SE on enamel and dentine, and the lowest by EP. Shear bond strengths were significantly higher on enamel when compared to dentine for five of the eight adhesives systems, and tensile bond strengths were significantly higher on enamel when compared to dentine for all but two systems.

Single-bottle adhesives behave as permeable membranes after polymerisation. II. Differential permeability reduction with an oxalate desensitiser

This study examined the changes in hydraulic conductance and ultrastructure of dentine bonded with simplified etch-and-rinse adhesives to oxalate desensitiser pre-treated acid-etched dentine. Human dentine disks were acid-etched, treated with an oxalate desensitiser (BisBlock, Bisco), and bonded with One-Step (OS), Single Bond (SB), OptiBond Solo Plus (OB) or Prime and Bond NT (PB). Similar disks from each group were acid-etched, and bonded without oxalate pre-treatment. Hydraulic conductance of the specimens was measured at 20 cm of water pressure and analysed with nonparametric statistical methods. Epoxy resin replicas of the smear layer-covered dentine and bonded dentine were examined with SEM for the extent of fluid transudation. Specimens bonded under perfusion were examined with TEM after tracer immersion. OB and PB exhibited a highly significant reversal of the reduced hydraulic conductance obtained with BisBlock on unbonded acid-etched dentine. Profuse water transudation across the bonded dentine was observed from the replicas. Adhesive interfaces were covered with spherical globules that interfered with dentine hybridization. Conversely, no significant difference in hydraulic conductance was observed in SB, between Bisblock pre-treated, unbonded and bonded acid-etched dentine. Significantly lower hydraulic conductance was shown on application of OS to Bisblock-treated acid-etched dentine. Water transudation was sparse, interfering surface globular structures were absent, and only angular subsurface crystals were seen in the dentinal tubules. Convective water fluxes through dentine may be reduced by applying Bisblock to acid-etched dentine before bonding with One-Step or Single Bond. However, reducing adhesive permeability with the use of oxalate desensitiser is not applicable to low acidity adhesives such as OptiBond Solo Plus and Prime and Bond NT.

Bond strengths of nine current dentine adhesive systems to primary and permanent teeth

The aim of this study was to compare the shear bond strength (SBS) of nine dentine bonding systems (DBS) of different classes to human primary and permanent dentine. Flat dentine occlusal surfaces were produced on human molars (100 primary, 100 permanent) by wet grinding on a 800-grit SiC paper. Nine DBS were applied following the manufacturers' instructions: One total etch multi-step system: Scotchbond Multipurpose Plus (3M/ESPE); Four total etch one-bottle system: Prime &Bond 2.1 (Dentsply), One Step (Bisco), Scotchbond 1 (3M/ESPE), and OptibondSolo Plus (Kerr); Three two-step self-etching primer systems: Clearfil Liner Bond 2 (Kuraray), Clearfil SE Bond (Kuraray), and Prime &Bond NT with NRC (Dentsply); An 'all-in-one' self-etching system: Prompt L-Pop (3M/ESPE). Composite (Z100; 3M/ESPE) cylinders (2 mm diameter, 3 mm high) were polymerized on the treated dentine surfaces and the specimens were stored at 37 degrees C for 24 h prior to testing. Twenty experimental groups were produced and tested. Statistical analysis revealed both a substrate and a bonding system effect. Two adhesive systems (One Step, Prime &Bond NT) had significantly higher bond strengths on permanent than on primary dentine. There was an effect of dentine bonding system on the mode of fracture. Although eight of the 10 DBS tested exhibited higher median SBS values on permanent dentine than on primary dentine, the dependent pairwise comparison identified a significant difference only for two groups. The use of simplified bonding systems does not necessarily result in improved bond strength to primary or to permanent dentine.

Effect of smear layer thickness and acidity of self-etching solutions on early and long-term bond strength to dentin

To evaluate the effect of smear layer thickness (SL) on early and 6-month bond strength (BS) of self-etching adhesives to dentin and to measure the ultimate microtensile strength (UTS) of the adhesives. Clearfil SE Bond; Optibond Solo Plus Self-Etch Primer; Tyrian Self Priming Etchant (TY) and as controls, Single Bond (SB) and Scotchbond Multi-Purpose Plus (SBMP) were applied on flat superficial dentin surface with thick and thin SL thicknesses. After adhesive's application (n=6) a resin build-up was made. After 24h, resin-dentin beams (0.8mm(2)) were prepared to be tested immediately and after 6-month (6M) at 0.5mm/min. For the UTS measurement, hour-glass specimens were prepared with the bonding resin alone or after mixing (1:1). BS values were analyzed by three-way repeated measures ANOVA and Tukey's multiple comparison tests. Two-way ANOVA (bonding resin and bonding resin+self-etching primer) and Tukey's test were used for the UTS values. The bonding resins were re-evaluated separately by a one-way ANOVA and Tukey's test, since Single Bond is a one-bottle adhesive (alpha=0.05). The SL thickness was not significant (p=0.64). BS values were reduced after 6M, except for the SBMP. TY provided the lowest BS mean while SB and SBMP the highest BS. The UTS of the SBMP was the highest. TY yielded the lowest UTS. Regression analysis revealed a linear and significant relationship between the UTS of self-etch systems and the mean BS (R=0.95, p=0.02). The performance of a self-etching system does not seem to be dependent on the SL thickness. The total-etch, three-step system provided the highest BS to dentin and maintained the BS stable over 6 months. The performance of the self-etching systems can be envisaged by their UTS.

Influence of Zinc-Oxide Eugenol, Formocresol, and Ferric Sulfate on Bond Stength of Dentin Adhesives to Primary Teeth

This study evaluated in vitro the influence of a temporary filling {zinc oxide-eugenol (ZOE)} and two pulpotomy agents {formocresol (FC) and ferric sulfate (FS)} on shear bond strength (SBS) of two dentin adhesives to the dentin of primary molars. A total of 80 dentin surfaces were prepared and randomly allocated into 10 groups of 8 specimens each. Groups were subjected to different treatments, which included covering with a paste of ZOE mixed at different powder:liquid (P:L) ratios, placement on a gauze soaked in FC or FS, or they received no pretreatment and served as a control. XRV Herculite composite cylinders were bonded to dentin surfaces using Prime and Bond NT adhesive resin or Opti Bond Solo Plus adhesive resin. SBSs were determined using the lnstron testing machine running at a crosshead speed of 0.5 mm/min. The use of ZOE mixed at the lower P:L ratio of 10g:2g significantly decreased the values of SBS of the two adhesives. The use of two pulpotomy agents (FC and FS) significantly decreased the SBS of the two adhesives. The bond strength to dentin of primary teeth was influenced by the pulpotomy agents used and the ZOE P:L ratio but not by the adhesive system used.

A resin impression SEM technique for examining the glass–ionomer cement chemical fusion zone

Examination of the auto-cure glass-ionomer cement (GIC)-tooth interface using conventional SEM techniques causes severe dehydration and subsequent fracturing of the GIC, hampering accurate assessment of the GIC-tooth interface. A simple, accurate impression technique was developed to examine the GIC chemical fusion zone. Samples of GIC were bonded to prepared cavities and tooth surfaces that had been conditioned with 10% polyacrylic acid for 10 s and allowed to mature for 24 h in neutral buffered saline, sectioned under water and then acid etched with 37% phosphoric acid for 30 s to remove sectioning smear layer and to highlight surface morphology, rinsed and gently dried. Optibond Solo Plus was then applied and photo-polymerized. Increments of posterior hybrid composite were then bonded onto the Optibond and photo-polymerized. The tooth sections with attached GIC were then dissolved off the bonded composite with 18% HCl for 4 days. Subsequent SEM examination of the resin impressions created with this technique provided high-quality, detailed images of the GIC chemical fusion zone, without the development of the fracture artefacts associated with the desiccation of GIC. The resin impression technique described proved to be a simple and successful method for providing accurate SEM images of the GIC-tooth chemical fusion.

Effect of self-etching adhesives on dentin permeability in a fluid flow model

Numerous self-etching bonding systems exist, with composition differing from one product to another. It is important for the clinician to know if they are all equally effective, and whether they provide an effective seal between dentin and restorative materials. This study was designed to measure the hydraulic conductance of physiologic saline across dentin after application of various self-etching bonding systems or of a 1-bottle adhesive system preceded by a phosphoric acid etch. One hundred extracted noncarious human third molars from patients 18-25 years old were used for this study. Dentin disks were cut from crown segments parallel to the occlusal surface at the top of the pulp cavity. The 100 disks, each 1 mm thick, were divided into 10 groups (n=10 per group), each of which was treated with 1 of 9 self-etching systems-AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, Etch & Prime 3.0, Prime & Bond NRC Nt, One-Up Bond F, optiBond solo Plus Self Etch, Prompt L-Pop, or Xeno III-or a control bonding system (Prime & Bond NT) preceded by a phosphoric acid etch. Hydraulic conductance, the volume of fluid transported across a known area of surface (0.28 cm2) per unit time under a unit pressure gradient (200 cm H2O), was analyzed for the adhesive systems using a fluid flow apparatus (Flodec). First, both sides of each specimen were etched with 36% phosphoric acid for 30 seconds, and the hydraulic conductance was measured every 30 seconds for 15 minutes. The initial set of measurements served as the reference value for each specimen. The measurements were repeated when a smear layer had been formed and, finally, after 1 of the 10 bonding systems had been applied. The data were analyzed using a 1-way ANOVA and Duncan's multiple range test (alpha=.05). The control 1-bottle adhesive used with a phosphoric acid pre-etch did not provide the largest reduction in penetration (42.3%). The greatest mean reduction (68.9%, P<.05) was observed with the self-etching product Xeno III. The mean reduction for the other materials tested were: One-Up Bond F, 60.5%; AdheSE, 58.2%; Etch & Prime 3.0, 56.8%; Adper Prompt L-Pop, 51%; optiBond solo Plus Self Etch, 45%; Clearfil SE Bond, 35.5%, Prime & Bond NRC Nt, 16.4%; and Prompt L-Pop, 16.3%. Within the limitations of this study, the self-etching systems tested produced different reductions in dentin permeability. For some, the reduction was much greater than the decrease in dentin permeability provided by the bonding system with a phosphoric acid pre-etch; for others, the reduction was small.