Dentine Bond Strength And Antimicrobial Activity Evaluation Of Adhesive Systems.

This study evaluated the dentine bond strength (BS) and the antibacterial activity (AA) of six adhesives against strict anaerobic and facultative bacteria. Three adhesives containing antibacterial components (Gluma 2Bond (glutaraldehyde)/G2B, Clearfil SE Protect (MDPB)/CSP and Peak Universal Bond (PUB)/chlorhexidine) and the same adhesive versions without antibacterial agents (Gluma Comfort Bond/GCB, Clearfil SE Bond/CSB and Peak LC Bond/PLB) were tested. The AA of adhesives and control groups was evaluated by direct contact method against four strict anaerobic and four facultative bacteria. After incubation, according to the appropriate periods of time for each microorganism, the time to kill microorganisms was measured. For BS, the adhesives were applied according to manufacturers' recommendations and teeth restored with composite. Teeth (n=10) were sectioned to obtain bonded beams specimens, which were tested after artificial saliva storage for one week and one year. BS data were analyzed using two-way ANOVA and Tukey test. Saliva storage for one year reduces the BS only for GCB. In general G2B and GCB required at least 24h for killing microorganisms. PUB and PLB killed only strict anaerobic microorganisms after 24h. For CSP the average time to eliminate the Streptococcus mutans and strict anaerobic oral pathogens was 30min. CSB showed no AA against facultative bacteria, but had AA against some strict anaerobic microorganisms. Storage time had no effect on the BS for most of the adhesives. The time required to kill bacteria depended on the type of adhesive and never was less than 10min. Most of the adhesives showed stable bond strength after one year and the Clearfil SE Protect may be a good alternative in restorative procedures performed on dentine, considering its adequate bond strength and better antibacterial activity.

Self-etch Adhesive Systems: A Literature Review.

This paper presents the state of the art of self-etch adhesive systems. Four topics are shown in this review and included: the historic of this category of bonding agents, bonding mechanism, characteristics/properties and the formation of acid-base resistant zone at enamel/dentin-adhesive interfaces. Also, advantages regarding etch-and-rinse systems and classifications of self-etch adhesive systems according to the number of steps and acidity are addressed. Finally, issues like the potential durability and clinical importance are discussed. Self-etch adhesive systems are promising materials because they are easy to use, bond chemically to tooth structure and maintain the dentin hydroxyapatite, which is important for the durability of the bonding.

Influence of different adhesive systems on the pull-out bond strength of glass fiber posts

This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost - Angelus-Brazil) cemented to root dentin with a resin cement (RelyX ARC - 3M/ESPE) associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP) Plus - 3M/ESPE), using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper Single Bond + #1 post (Reforpost - Angelus) + four #1 accessory posts (Reforpin - Angelus) + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37°C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf) and standard deviation were: G1- 29.163 ± 7.123; G2- 37.752 ±13.054. Statistical analysis (Student's t-test; a=0.05 showed no statistically significant difference (p<0.05) between the groups. Adhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1). The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength.

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (α=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (±4.29); II-8.57 (±3.19); III-7.97 (±2.16); IV-12.56 (±3.11); V-11.45 (±3.77); and VI-7.47 (±1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

Influence of intrapulpal pressure simulation on the bond strength of adhesive systems to dentin

The purpose of this study was to evaluate the influence of intrapulpal pressure simulation on the bonding effectiveness of etch & rinse and self-etch adhesives to dentin. Eighty sound human molars were distributed into eight groups, according to the permeability level of each sample, measured by an apparatus to assess hydraulic conductance (Lp). Thus, a similar mean permeability was achieved in each group. Three etch & rinse adhesives (Prime & Bond NT - PB, Single Bond -SB, and Excite - EX) and one self-etch system (Clearfil SE Bond - SE) were employed, varying the presence or absence of an intrapulpal pressure (IPP) simulation of 15 cmH2O. After adhesive and restorative procedures were carried out, the samples were stored in distilled water for 24 hours at 37°C, and taken for tensile bond strength (TBS) testing. Fracture analysis was performed using a light microscope at 40 X magnification. The data, obtained in MPa, were then submitted to the Kruskal-Wallis test ( a = 0.05). The results revealed that the TBS of SB and EX was significantly reduced under IPP simulation, differing from the TBS of PB and SE. Moreover, SE obtained the highest bond strength values in the presence of IPP. It could be concluded that IPP simulation can influence the bond strength of certain adhesive systems to dentin and should be considered when in vitro studies are conducted.

Micromorphology of Resin-Dentin Interfaces Using One-Bottle Etch&Rinse and Self-Etching Adhesive Systems on Laser-Treated Dentin Surfaces: A Confocal Laser Scanning Microscope Analysis

Background and Objectives: This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on dentin surfaces treated with Er:YAG laser using two irradiation parameters. Study Design: Occlusal flat dentin surfaces of 36 human third molars were assigned into nine groups (n = 4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S3 Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate dextran and were applied to dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7 J/cm(2)) or 200 mJ/pulse (64.5 J/cm(2)), or were applied to untreated dentin surfaces (control group). The ASs were light-activated following MI and the bonded surfaces were restored with resin composite Z250 (3M ESPE). After 24 hours of storage in vegetable oil, the restored teeth were vertically, serially sectioned into 1-mm thick slabs, which had the adhesive interfaces analyzed with confocal laser microscope (CLSM-LSM 510 Meta). CLSM images were recorded in the fluorescent mode from three different regions along each bonded interface. Results: Non-uniform HL was created on laser-irradiated dentin surfaces regardless of laser irradiation protocol for all AS, while regular and uniform HL was observed in the control groups. ""Stretch mark""-like red lines were found within the HL as a result of resin infiltration into dentin microfissures, which were predominantly observed in 200 mJ/pulse groups regardless of AS. Poor resin infiltration into peritubular dentin was observed in most regions of adhesive interfaces created by all ASs on laser-irradiated dentin, resulting in thin resin tags with neither funnel-shaped morphology nor lateral resin projections. Conclusion: Laser irradiation of dentin surfaces at 120 or 200 mJ/pulse resulted in morphological changes in HL and resin tags for all ASs evaluated in the study. Lasers Surg. Med. 42:662-670, 2010. (C) 2010 Wiley-Liss, Inc.

Evaluation of three different adhesive systems using a bacterial method to develop secondary caries in vitro

Purpose: To assess the effects of three different dental adhesive systems on the formation of secondary root caries, in vitro, with a standardized interfacial gap in a filled cavity model. Methods: 40 sound human molars were selected and randomly assigned to four experimental groups: Clearfil SE Bond (CSEB), Xeno III (X-III), Scotchbond Multi-Purpose Plus (SBMP) and negative control (NC) without an adhesive system. After the standardized Class V cavity preparations on the buccal and lingual surfaces, restorations were placed with resin composite (Filtek Z250) using a standardized interfacial gap, using a 3 x 2 mm piece of 50 mu m metal matrix. The teeth were sterilized with gamma irradiation and exposed to a cariogenic challenge using a bacterial system with Streptococcus mutans. Depth and extension of wall lesions formed and the depth of outer lesions were measured by software coupled with light microscopy. Results: For wall lesion extension the ANOVA test showed differences between groups except between X-HI and SBMP (P= 0.294). The Tukey`s test of confidence intervals indicated smaller values for the CSEB group than for the others. For wall lesion depth the CSEB group also presented the smallest mean values of wall lesion depth when compared to the others (P< 0.0001) for all comparisons using Tukey`s test. Regarding outer lesion depth, all adhesives showed statistically similar behavior. SEM evaluation of the morphologic appearance of caries lesions confirmed the statistical results showing small caries lesion development for cavities restored with CSEB adhesive system, which may suggest that this adhesive system interdiffusion zone promoted a good interaction with subjacent dentin protecting the dental tissues from recurrent caries. (Am J Dent 2010;23:93-97).

In Vitro Microleakage of Composite Restorations Prepared by Er:YAG/Er,Cr:YSGG Lasers and Conventional Drills Associated with Two Adhesive Systems

Purpose: The objective of this in vitro study was to compare the degree of microleakage of composite restorations performed by lasers and conventional drills associated with two adhesive systems. Materials and Methods: Sixty bovine teeth were divided into 6 groups (n = 10). The preparations were performed in groups 1 and 2 with a high-speed drill (HID), in groups 3 and 5 with Er:YAG laser, and in groups 4 and 6 with Er,Cr:YSGG laser. The specimens were restored with resin composite associated with an etch-and-rinse two-step adhesive system (Single Bond 2 [SB]) (groups 1, 3, 4) and a self-etching adhesive (One-Up Bond F [OB]) (groups 2, 5, 6). After storage, the specimens were polished, thermocycled, immersed in 50% silver nitrate tracer solution, and then sectioned longitudinally. The specimens were placed under a stereomicroscope (25X) and digital images were obtained. These were evaluated by three blinded evaluators who assigned a microleakage score (0 to 3). The original data were submitted to Kruskal-Wallis and Mann-Whitney statistical tests. Results: The occlusal/enamel margins demonstrated no differences in microleakage for all treatments (p > 0.05). The gingival/dentin margins presented similar microleakage in cavities prepared with Er:YAG, Er,Cr:YSGG, and HD using the etch-and-rinse two-step adhesive system (SB) (p > 0.05); otherwise, both Er:YAG and Er,Cr:YSGG lasers demonstrated lower microleakage scores with OB than SB adhesive (p < 0.05). Conclusion: The microleakage score at gingival margins is dependent on the interaction of the hard tissue removal tool and the adhesive system used. The self-etching adhesive system had a lower microleakage score at dentin margins for cavities prepared with Er:YAG and Er,Cr:YSGG than the etch-and-rinse two-step adhesive system.

Effects of Nd:YAG Laser Irradiation on the Hybrid Layer of Different Adhesive Systems

Purpose: The aim of this in vitro study was to evaluate the microtensile bond strength (mu TBS) and hybrid layer morphology of different adhesive systems, either followed by treatment with Nd:YAG laser irradiation or not. Previous studies have shown the effects of Nd:YAG laser irradiation on the dentin surface at restoration margins, but there are few reports about the significance of the irradiation on the hybrid layer. Materials and Methods: The flattened coronal and root dentin samples of 24 bovine teeth were randomly divided into 8 groups, according to the adhesive system used - Scotchbond Multi Purpose (SBMP) or Clearfil SE Bond (CSEB) - and were either irradiated with Nd:YAG or not, with different parameters: 0.8 W/10 Hz, 0.8 W/20 Hz, 1.2 W/10 Hz, 1.2 W/20 Hz. The left sides of specimens were the control groups, and right sides were irradiated. A composite crown was built over bonded surfaces and stored in water (24 h at 37 degrees C). Specimens were sectioned vertically into slabs that were subjected to mu TBS testing and observed by SEM. Results: Control groups (27.81 +/- 1.38) showed statistically higher values than lased groups (21.37 +/- 0.99), and CSEB control group values (31.26 +/- 15.71) were statistically higher than those of SBMP (24.3 +/- 10.66). There were no significant differences between CSEB (20.34 +/- 10.01) and SBMP (22.43 +/- 9.82) lased groups. Among parameters tested, 0.8 W/10 Hz showed the highest value (25.54 +/- 11.74). Nd:YAG laser irradiation caused dentin to melt under the adhesive layer of both adhesive systems tested. Conclusion: With the parameters used in this study, Nd:YAG laser irradiation of the hybrid layer promoted morphological changes in dentin and negatively influenced the bond strength of both adhesive systems.

Short-term in situ/ex vivo study of the anticariogenic potential of a resin-modified glass-ionomer cement associated with adhesive systems

Objective: As resin-modified glass-ionomer cement (RMGIC) is an adhesive material, its association to dentin bonding agents (DBAs) was previously proposed. This study investigated the adjunctive behavior of an RMGIC with etch-and-rinse bonding systems under in situ/ex vivo cariogenic challenge. Method and Materials: Bovine enamel blocks (3 3 2 mm) were randomly assigned to group VP, Vitremer + its own primer (3M ESPE); group VSB, Vitremer + Single Bond (3M ESPE); and group VPB, Vitremer + Prime & Bond 2.1 (Dentsply). Two blocks of each group were randomly placed in an acrylic palatal appliance, so each appliance included six blocks. Volunteers (n = 10) wore these appliances according to given instructions to promote a sucrose challenge eight times/day for 15 days. After this period, the blocks were removed from the devices and cleaned, and demineralization was assessed through longitudinal microhardness analysis (Knoop indenter, 25 g/5 s). Data were submitted to three-way ANOVA and Tukey test (P < .05). Results: No treatment was able to completely avoid demineralization. All materials showed a statistically significant difference in mineral loss when the microhardness on the outer enamel was compared with deeper regions (P < .05). Conclusion: Association of the tested RMGICs with etch-and-rinse DBAs did not seem to be more beneficial against caries than the conventional treatment with RMGIC. (Quintessence Int 2010; 41: e192-e199)

Enamel Wetness Effects on Bond Strength Using Different Adhesive Systems

Objective: To evaluate, through the application of different dentin bonding systems, the influence of wetness on shear bond strength in enamel. Methods: This study evaluated three etch-and-rinse adhesive systems (Scotchbond MP [used with and without primer]; Singlebond; and Prime&Bond 2.1) and two self-etching adhesive systems (Clearfil SE Bond; and Xeno IV). Flat bovine enamel surfaces were either air-dried for 30 seconds or blotted with absorbent paper after acid-etching for the conventional bonding agents or before the application of self-etching bonding agents. The resin composite EsthetX was bonded to flat surfaces that had been treated with one of the adhesives, following the manufacturer`s instructions. After being stored in water at 37 degrees C for one week, bonded specimens were broken in shear. Data were evaluated with two-way analysis of variance (ANOVA) and Student-Newman-Keuls tests (alpha=0.05). For comparing each condition individually, regardless of the adhesive or wetness condition, a one-way ANOVA and a Student-Newman-Keuls test (alpha=0.05) were applied. Results: The two-way ANOVA showed significant differences among adhesive systems. An interaction effect was also observed (p < 0.05), but wetness did not influence shear bond strength (p=0.98). The one-way ANOVA showed that the all-in-one adhesive was the only material influenced by the presence of water at the enamel`s surface. Conclusion: The all-in-one adhesive behaved differently depending on whether the enamel surface was dry or wet.

Bond strength of Epiphany (TM) Sealer combined with different adhesive systems photo-activated with LED and QTH

The Epiphany (TM) Sealer is a new dual-curing resin-based sealer and has been introduced as an alternative to gutta-percha and traditional root canal sealers. The canal filling is claimed to create a seal with the dentinal tubules within the root canal system producing a `monoblock` effect between the sealer and dentinal tubules. Therefore, considering the possibility to incorporate the others adhesive systems, it is important to study the bond strength of the resulting cement. Forty-eight root mandibular canines were sectioned 8-mm below CEJ. The dentine discs were prepared using a tapered diamond bur and irrigated with 1% NaOCl and 17% EDTA. Previous the application Epiphany (TM) Sealer, the Epiphany (TM) Primer, AdheSE, and One Up Bond F were applied to the root canal walls. The LED and QTH (Quartz Tungsten Halogen) were used to photo-activation during 45 s with power density of 400 and 720 mW/cm(2), respectively. The specimens were performed on a universal testing machine at a cross-head speed of 1 mm/min until bond failure occurred. The force was recorded and the debonding values were used to calculate Push-out bond strength. The analysis of variance (ANOVA) and Tukey`s post-hoc tests showed significant statistical differences (P < 0.05) to Epiphany (TM) Sealer/Epiphany (TM) Primer/QTH and EpiphanyTM Sealer/AdheSE/QTH, which had the highest mean values of bond strength. The efficiency of resin-based filling materials are dependent the type of light curing unit used including the power density, the polymerization characteristics of these resin-based filling materials, depending on the primer/adhesive used.

Shear Bond Strength and Ultrastructural Interface Analysis of Different Adhesive Systems to Bleached Dentin

Background: It remains unclear as to whether or not dental bleaching affects the bond strength of dentin/resin restoration. Purpose: To evaluated the bond strength of adhesive systems to dentin submitted to bleaching with 38% hydrogen peroxide (HP) activated by LED-laser and to assess the adhesive/dentin interfaces by means of SEM. Study design: Sixty fragments of dentin (25 mm(2)) were included and divided into two groups: bleached and unbleached. HP was applied for 20 s and photoactivated for 45 s. Groups were subdivided according to the adhesive systems (n = 10): (1) two-steps conventional system (Adper Single Bond), (2) two-steps self-etching system (Clearfil standard error (SE) Bond), and (3) one-step self-etching system (Prompt L-Pop). The specimens received the Z250 resin and, after 24 h, were submitted to the bond strength test. Additional 30 dentin fragments (n = 5) received the same surface treatments and were prepared for SEM. Data were analyzed by ANOVA and Tukey`s test (alpha = 0.05). Results: There was significant strength reduction in bleached group when compared to unbleached group (P < 0.05). Higher bond strength was observed for Prompt. Single Bond and Clearfil presented the smallest values when used in bleached dentin. SEM analysis of the unbleached specimens revealed long tags and uniform hybrid layer for all adhesives. In bleached dentin, Single Bond provided open tubules and with few tags, Clearfil determined the absence of tags and hybrid layer, and Prompt promoted a regular hybrid layer with some tags. Conclusions: Prompt promoted higher shear bond strength, regardless of the bleaching treatment and allowed the formation of a regular and fine hybrid layer with less deep tags, when compared to Single Bond and Clearfil. Microsc. Res. Tech. 74:244-250, 2011. (C) 2010 Wiley-Liss, Inc.

Bond strength tests of dental adhesive systems and their correlation with clinical results : a meta-analysis

OBJECTIVE: To evaluate the variability of bond strength test results of adhesive systems (AS) and to correlate the results with clinical parameters of clinical studies investigating cervical restorations. MATERIALS AND METHODS: Regarding the clinical studies, the internal database which had previously been used for a meta-analysis on cervical restorations was updated with clinical studies published between 2008 and 2012 by searching the PubMed and SCOPUS databases. PubMed and the International Association for Dental Research abstracts online were searched for laboratory studies on microtensile, macrotensile and macroshear bond strength tests. The inclusion criteria were (1) dentin, (2) testing of at least four adhesive systems, (3) same diameter of composite and (4) 24h of water storage prior to testing. The clinical outcome variables were retention loss, marginal discoloration, detectable margins, and a clinical index comprising the three parameters by weighing them. Linear mixed models which included a random study effect were calculated for both, the laboratory and the clinical studies. The variability was assessed by calculating a ratio of variances, dividing the variance among the estimated bonding effects obtained in the linear mixed models by the sum of all variance components estimated in these models. RESULTS: Thirty-two laboratory studies fulfilled the inclusion criteria comprising 183 experiments. Of those, 86 used the microtensile test evaluating 22 adhesive systems (AS). Twenty-seven used the macrotensile test with 17 AS, and 70 used the macroshear test with 24 AS. For 28 AS the results from clinical studies were available. Microtensile and macrotensile (Spearman rho=0.66, p=0.007) were moderately correlated and also microtensile and macroshear (Spearman rho=0.51, p=0.03) but not macroshear and macrotensile (Spearman rho=0.34, p=0.22). The effect of the adhesive system was significant for microtensile and macroshear (p<0.001) but not for macrotensile. The effect of the adhesive system could explain 36% of the variability of the microtensile test, 27% of the macrotensile and 33% of the macroshear test. For the clinical trials, about 49% of the variability of retained restorations could be explained by the adhesive system. With respect to the correlation between bond strength tests and clinical parameters, only a moderate correlation between micro- and macrotensile test results and marginal discoloration was demonstrated. However, no correlation between these tests and a retention loss or marginal integrity was shown. The correlation improved when more studies were included compared to assessing only one study. SIGNIFICANCE: The high variability of bond strength test results highlights the need to establish individual acceptance levels for a given test institute. The weak correlation of bond-strength test results with clinical parameters leads to the conclusion that one should not rely solely on bond strength tests to predict the clinical performance of an adhesive system but one should conduct other laboratory tests like tests on the marginal adaptation of fillings in extracted teeth and the retention loss of restorations in non-retentive cavities after artificial aging.

Novel adhesive systems based on neoprene-phenolic blends

The aim of the investigation is to develop new high performance adhesive systems based on neoprene-phenolic blends. Initially the effect of addition of all possible ingredients like fillers, adhesion promoters, curing agents and their optimum compositions to neoprene solution is investigated. The phenolic resin used is a copolymer of phenol-cardanolformaldehyde prepared in the laboratory. The optimum ratio between phenol and cardanol that gives the maximum bond strength in metal-metal, rubber-rubber and rubber-metal specimens has been identified. Further the ratio between total phenols and formaldehyde is also optimised. The above adhesive system is further modified by the addition of epoxidized phenolic novolacs. For this purpose, phenolic novolac resins are prepared in different stoichiometric ratios and are subsequently epoxidized. The effectiveness of the adhesive for bonding different metal and rubber substrates is another part of the study. To study the ageing behaviour, different bonded specimens are exposed to high temperature, hot water and salt water and adhesive properties have been evaluated. The synthesized resins have been characterized by FTIR , HNMR spectroscopy. The molecular weights of the resins have been obtained by GPC. Thermogravimetric analysis and differential scanning calorimetry are used to study the thermal properties. The fractured surface analysis is studied by scanning electron microscopy. The study has brought to light the influence of phenol/ formaldehyde stoichiometric ratio, addition of cardanol (a renewable resource), adhesion promoters and suitability of the adhesive for different substrates and the age resistance of adhesive joints among other things.