Clearfil Protect Bond Research Articles

Inhibition of cell survival, viability and proliferation by dentin adhesives after direct and indirect exposure in vitro

The influence of dentin adhesive systems (Scotchbond Multi-Purpose, XP Bond, Xeno V, Clearfil Protect Bond, AdheSE) on cell survival, viability and proliferation was characterized after direct and indirect exposure using different cell culture techniques. The primers and cured bonding parts were directly exposed to cells using cell culture inserts, and complete materials were analyzed in a dentin barrier test. Cell responses were examined in 3T3 mouse fibroblasts after 24- and 72-h exposure periods by the estimation of total cell numbers (survival), apoptosis (viability) and cell proliferation. Cell numbers were effectively reduced by the primers of AdheSE, Protect Bond, and Scotchbond Multi-Purpose as well as XP bond after direct exposure in a cell culture insert test device. Likewise, Scotchbond Multi-Purpose primer induced a rate of apoptosis (93.9%) even higher than detected with Protect Bond primer (91.6%). Cell proliferation was entirely inhibited by primers and by Xp Bond as well. The Scotchbond Multi-Purpose was most cytotoxic in a dentin barrier test device after a 24-h indirect exposure. It also increased the percentage of cells in apoptosis to 15.4% compared to untreated controls. Unpolymerized primers of dentin adhesives were more cytotoxic than polymerized bonding counterparts. Moreover, total etch dentin adhesives were more cytotoxic than self-etch adhesives. When dentin adhesives are used in deep cavities without a protective dentin barrier the leachable hydrophobic and hydrophilic component of dentin adhesive systems can penetrate to the pulp and may induce cytotoxic responses in pulp tissues.

<I>In vitro </I>permeability of etch-and-rinse and self-etch adhesives used for immediate dentin sealing

To investigate the permeability of deep dentin following immediate sealing with different etch-and-rinse and self-etch adhesives (Single Bond 2, Adper Prompt L-Pop, Clearfil Protect Bond, Clearfil S3 Bond, G-Bond) and a dentin desensitizer (Gluma). Fluid-transport model was used to measure fluid conductance during and after application of adhesives. Polyvinylsiloxane impressions of bonded dentin were taken to monitor fluid transudation from the surface of the adhesives. The area and number of dentinal fluid droplets and/or blisters were calculated using image analysis. None of the adhesives were able to block fluid conductance completely. The fluid conductance values of the adhesives displayed the following statistical ranking (p<0.05): G-Bond≤Clearfil Protect Bond<Smear-layer-covered dentin<S3 Bond≤Single Bond 2≤Adper Prompt L-Pop<Gluma Desensitizer<Acid-etched dentin. Highly significant correlation was observed between the permeability of the tested adhesives and the area fraction of fluid droplets/blisters on the adhesive surfaces (r=0.99, p<0.01).

Apoptotic effect of different self-etch dental adhesives on odontoblasts in cell cultures

ObjectivesWe aimed to evaluate the potential cytotoxicity (apoptosis-induction) of three types of self-etch dental adhesives: two-component one-step (Xeno III), two-component two-steps (Clearfil Protect Bond) and one-component one-step (Xeno V) on cultured odontoblasts. MethodsEach adhesive was prepared to simulate its clinical manipulation. Cured sterile individual masses were immersed in DMEM and left at 37°C for 24h. Then a volume of 100μL of the extract medium was added to the cultured odontoblasts and incubated for additional 24h, 48h and 72h, respectively. Acridine orange–propidium iodide (AO–PI) labelling was employed to assess the proportion of dead to total number of cells. In addition, an in situ apoptosis detection kit was used to evaluate the DNA cleavage and chromatin condensation employing the immunohistochemical (IHC) technique. Statistical analysis of the data was performed using one-way ANOVA. ResultsBoth apoptosis evaluation methods revealed comparable results with the exception that IHC showed 5–7% less number of dead cells when compared to similar groups evaluated by AO–PI. The percentages of dead to total cells after treatment with Clearfil Protect Bond, Xeno III and Xeno V, were significantly different from the percentage of dead cells after treatment with DMEM alone (−ve control), P value <0.05 and Xeno V dental adhesive had the weakest cytotoxic effect on odontoblasts followed by Xeno III especially after 24h of incubation. Clearfil Protect Bond had the strongest cytotoxic effect on odontoblasts that was almost closer to that of Staurosporine in DMEM (+ve control). ConclusionAll tested dental adhesives had remarkable adverse effect on the odontoblasts in vitro; this might be of concern when applied clinically in deep cavities where such cytotoxic chemicals become in close contact to dental pulp. Therefore, further in vivo studies on animal models are recommended to support or refute these in vitro findings.

In vitro enterococcus faecalis biofilm formation on five adhesive systems

Objective: To determine the E. faecalis biofilm formation on the surface of five adhesive systems (AS) and its relationship with roughness. Study Design: The formation of E. faecalis biofilms was tested on the surface of four dual-cure AS: AdheSE DC, Clearfil DC Bond, Futurabond DC and Excite DSC and one light-cure antimicrobial AS, Clearfil Protect Bond, after 24 hours of incubation, using the MBEC high-throughput device. Results: E. faecalis biofilms grew on all the adhesives. The least growth of biofilm was on Excite DSC, Clearfil Protect Bond, and the control. Futurabond DC resulted in the greatest roughness and biofilm amount. There was a close relationship between the quantity of biofilm and roughness, except for Clearfil Protect Bond, which showed little biofilm but high roughness. Conclusion: None of the tested AS prevented E. faecalis biofilm formation, although the least quantity was found on the surface of Clearfil Protect Bond. Key words:Adhesive systems, biofilm, Enterococcus faecalis, roughness.

Differential nanofiller cluster formations in dental adhesive systems

Nanofillers are added to dental adhesives to improve mechanical properties of the hybrid layer. Ethanol or water added to the demineralized dentin to improve adhesive infiltration may produce filler aggregation. To assess the effect of 5 vol% water or ethanol addition on nanoparticles distribution in dental adhesives. Six available commercial adhesives systems were selected: Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), FL-Bond (FLB), Clearfil S3 (CS3), Bond Force (BF), One Up Bond F plus (OUB), and an experimental adhesive system without filler (EXP). Polymer films were obtained by adding 0 (control) or 5 vol% water or ethanol into the bonding resins. Preparations were light-cured (40 s). Three specimens were analyzed for each mixture. Three phases and 3D images were taken from each specimen by means of an atomic force microscope in taping mode (TM/AFM). Cluster sizes and surface nanoroughness were assessed. Control specimens from CSE, FLB, OUB, and BF presented clusters. The addition of solvents lead to particles aggregation in tested bonding resins. Ethanol addition produced more aggregates, particularly in adhesives containing fluoraluminosilicate as fillers. Nanofillers aggregation occurred in all adhesive systems in presence of additional solvents. In general, aggregate sizes were higher after the addition of ethanol. Formed clusters size values are always above the dimensions of the spaces existing between the demineralized collagen fibers.

Effect of the erbium:yttrium-aluminum-garnet laser or diamond bur cavity preparation on the marginal microleakage of class V cavities restored with different adhesives and composite systems

The aim of this in vitro study was to compare the microleakage of Er:YAG laser and diamond bur on different bonding systems in class V restorations. Class V cavities were prepared with Er:YAG laser or diamond bur on 80 intact human molars. Teeth were randomly distributed into ten groups and cavities were restored with CeramX duo (DENTSPLY) or Filtek Silorane (3M/ESPE) using different bonding materials (One Coat 7.0 (Coltène), XP Bond (DENTSPLY), Clearfil Protect Bond (Kuraray), AdperSE (3M/ESPE), and Silorane System Adhesive (3M/ESPE). All specimens were subjected to thermocycling and load cycling. After being immersed in silver nitrate dye, the specimens were sectioned. Microleakage was evaluated by stereomicroscope and SEM. Data were statistically analyzed by one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Statistically differences were found between groups (p > 0.05) and cavities prepared with the Er:YAG laser showed higher microleakage than diamond bur. The microleakage of different bonding systems was influenced by the choice of diamond bur or Er:YAG laser for class V composite cavity preparation.

Genotoxicity evaluation of dentine bonding agents by comet assay

To evaluate the genotoxicity of four different adhesives, Clearfil SE Bond, SL Bond, i Bond and Clearfil Protect Bond and the primers of Clearfil SE Bond and Clearfil Protect Bond. Genotoxicity assessment of the adhesives and primers was carried out in vitro in human lymphocytes at different elution concentrations, using the alkaline single-cell gel electrophoresis technique (comet assay). After the incubation of lymphocytes with varying volumes of the test agent, cells were embedded in a low-melting-point agarose suspension and then lysed in alkaline (pH>13) conditions. Electrophoresis was performed on the suspended lysed cells followed by visual analysis with staining of DNA. Fluorescence was than calculated to determine the extent of DNA damage using imaging software. Statistical comparison of the results was carried out by one-way analysis of variance (anova). A significant increase (P<0.001) compared to untreated controls in DNA damage was observed with 'Clearfil Protect Bond' and 'Clearfil SE Bond' primer in human lymphocytes at concentrations of 2.5 and 5.0 mg mL(-1). Clearfil Protect Bond and Clearfil SE Bond adhesives induced significant (P < 0.001) DNA damage only at the higher concentration of 5.0 mg mL(-1) . No significant increase in DNA damage was observed with SL Bond and i Bond. No significant DNA damage was observed with any dentine bonding agents at the lower concentration of 1.25 mg mL(-1) . 'Clearfil Protect Bond' and 'Clearfil SE Bond' primers/adhesives increased DNA damage in human peripheral lymphocytes in high doses.

Effect of resin coating and occlusal loading on microleakage of class II computer-aided design/computer-aided manufacturing fabricated ceramic restorations: A confocal microscopic study

Objective. To evaluate the effect of resin coating and occlusal loading on microleakage of class II computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic restorations. Material and methods. Molars were prepared for an mesio-occlusal-distal (MOD) inlay and were divided into two groups: non-coated (controls); and resin-coated, in which the cavity was coated with a combination of a dentin bonding system (Clearfil Protect Bond) and a flowable resin composite (Clearfil Majesty Flow). Ceramic inlays were fabricated using the CAD/CAM technique (CEREC 3) and cemented with resin cement (Clearfil Esthetic Cement). After 24 h of water storage, the restored teeth in each group were divided into two subgroups: unloaded or loaded with an axial force of 80 N at a rate of 2.5 cycles/s for 250,000 cycles while stored in water. After immersion in 0.25% Rhodamine B solution, the teeth were sectioned bucco-lingually at the mesial and distal boxes. Tandem scanning confocal microscopy (TSM) was used for evaluation of microleakage. The locations of the measurements were assigned to the cavity walls and floor. Results. Loading did not have a significant effect on microleakage in either the resin-coated or non-coated group. Resin coating significantly reduced microleakage regardless of loading. The cavity floor exhibited greater microleakage compared to the cavity wall. TSM observation also revealed that microleakage at the enamel surface was minimal regardless of resin coating. In contrast, non-coated dentin showed extensive leakage, whereas resin-coated dentin showed decreased leakage. Conclusions. Resin coating with a combination of a dentin-bonding system and a flowable resin composite may be indicated prior to impression-taking when restoring teeth with CAD/CAM ceramic inlays in order to reduce microleakage at the tooth–resin interface.

Assessment of antibacterial properties of newer dentin bonding agents: An in vitro study

Aim:To evaluate and compare the antibacterial activity of newer dentin bonding agents on Streptococcus mutans using the direct contact test.Materials and Methods:Streptococcus mutans was used as test organism and a direct contact test was performed. The dentin bonding agents to be tested were grouped as Group I, Clearfil Protect Bond, Group II, Adper Easy One, and Group III, Prime and Bond NT. For the direct contact test, three microtiter plates consisting of 96 wells each were taken (288 wells). These wells were divided into three groups of 96 wells; 16 wells of a microtiter plate were utilized, of which four were designated as ‘A’ wells (with the dentin bonding agent and bacterial suspension), another four as ‘B’ wells (without the dentin bonding agent, but with the bacterial suspension), another four as the ‘C’ wells (with the tested material, but without bacteria, which served as the negative control), and the remaining four as the ‘D’ wells (without the dentin bonding agent, which served as the positive control). Each group was treated with their respective bonding agents as per the manufactures instructions. Broth of 15 μL was then transferred from the A wells into an adjacent set of B wells containing fresh medium (215 μL). This resulted in two sets of four wells for each tested material containing an equal volume of liquid medium, so that bacterial growth was monitored both in the presence and in the absence of the tested material. The plate was placed for incubation at 37°C in the microplate reader and the optical density in each well was measured at 600 nm. The readings were taken at regular intervals. (Every 30 minutes for 16 hours).Results:The Dentin bonding agents evaluated in this study showed different inhibitory effects. Clearfil Protect Bond and Prime and Bond NT were most effective, and Adper Easy One was least effective against Streptococcus mutans.Interpretation and Conclusion:The Dentin bonding agents evaluated in this study showed different inhibitory effects. Clearfil Protect Bond and Prime and Bond NT were most effective, and Adper Easy One was the least effective against Streptococcus mutans. Hence, the incorporation of antibacterial agents into the dentin bonding agents may become an essential factor in inhibiting residual bacteria in the cavity and secondary caries.

Evaluation of cytotoxic effects of six self-etching adhesives with direct and indirect contact tests

This study evaluated the cytotoxicity of self-etching primers/adhesives by direct contact and dentin barrier tests. The three two-step self-etching systems Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Prime&Bond NT/NRC (PB) and one-step self-etching systems Reactmer Bond (RB), Clearfil Tri-S Bond (CTS), and Adper Prompt L-Pop (AP) were examined. In direct contact tests, L929 cells were cultured in the presence of diluted solutions (50, 20, 10, and 1%) of primer/conditioner of adhesive systems. For dentin barrier tests, each system was applied onto 0.5 or 1.5 mm thick human dentin assembled in a simple pulp chamber device and incubated for 24 h at 37°C to make the diffusive components contact the L929 cells placed at the bottom of the chamber. The cytotoxic effects were assessed by MTT assay. Cell culture without application of any primers/adhesives served as the control for both tests. One-way ANOVA and Tukey HSD tests were used for statistical analyses. The direct contact tests demonstrated that CSE and CPB were less toxic than the other materials at all dilutions. In the dentin barrier tests, toxic effects of materials were reduced with an increase in thickness of intervening dentin. CSE and CPB showed less cytotoxicity than the other adhesives (p<0.05) when applied to 0.5 mm-thick dentin, and CSE was the least toxic in the 1.5 mm-dentin group (p<0.05). Dentin thickness positively affected biocompatibility of the tested bonding systems. Two-step self-etching systems with HEMA-based primers were more biocompatible than other self-etching adhesives.

Effect of Ozone Pretreatment on the Microleakage of Pit and Fissure Sealants

This study investigated the effect of ozone pretreatment on the microleakage and marginal integrity of pit and fissure sealants placed with or without a self-etch 6th generation adhesive. Freshly-extracted, human third molars were randomly assigned into two main groups (n = 48): Group A: Fissures were pretreated with ozone; Group B: Fissures were left untreated. The teeth were further randomly divided into two subgroups (n = 24/each) so that half of teeth were sealed with a conventional fissure sealant (Fissurit F, Voco, Germany), while the remaining half received the same sealant bonded with a self-etch adhesive (Clearfil Protect Bond, Kuraray, Japan). Following thermal cycling (1000X), the specimens were subjected to dye penetration within 0.5% basic fuchsin for 24h. The extent of dye penetration was measured by image analysis. Kruskal Wallis and Mann-Whitney U tests were used for statistical analysis of the data (p = 0.05). Two randomly-selected sections from each group were observed under SEM RESULTS: In all groups, ozone pretreatment significantly reduced the extent of microleakage (p < 0.001). SEM investigation demonstrated better adaptation of the sealants in ozone-pretreated groups. Clearfil Protect Bond did not improve the marginal seal of Fissurit F (p > 0.05). Ozone pretreatment favorably affected the marginal sealing ability of the tested fissure sealants.

Effect of reducing agents on bond strength to NaOCl-treated dentin

Objective The purpose of this study was to evaluate the effect of three antioxidant/reducing agents with different application times on microtensile bond strengths to sodium hypochlorite-treated dentin. Methods The occlusal surfaces of 24 extracted human third molars were horizontally cut to expose sound dentin. The teeth were divided into eight groups. The dentin surfaces of the teeth were treated as follows: group 1, no treatment; group 2, treated with 6% sodium hypochlorite (NaOCl) for 30 s; groups 3–8, applications of 10% sodium ascorbate solution, 100 μM rosmarinic acid solution or Accel for 5 or 10 s after the same treatment as in group 2. All treated dentin surfaces were bonded with a 2-step self-etching adhesive system (Clearfil Protect Bond) and restored with a resin composite (Clearfil AP-X). After storage in water for 24 h, the bonded specimens were subjected to the microtensile bond test at a crosshead speed of 1.0 mm/min. Data were analyzed by a one-way ANOVA and Tukey test ( p < 0.05). Results The NaOCl-treated group had significantly lower bond strength than the control group ( p < 0.05). The application of sodium ascorbate solution for 5 or 10 s did not significantly increase the compromised bonding to NaOCl-treated dentin ( p > 0.05). On the other hand, Accel and rosmarinic acid solution had significant reversal effects with the same application times ( p < 0.05). Significance The reversal effect on compromised bonding to NaOCl-treated dentin depended upon the type of antioxidant within the short application time. Applying Accel or rosmarinic acid for 5 or 10 s improved bond strengths to NaOCl-treated dentin.

Effect of Chlorhexidine Gluconate, Clearfil Protect Bond, and KTP Laser on Microleakage Under Metal Orthodontic Brackets with Thermocycling

The purpose of this study was to evaluate the effects of antimicrobial pretreatments [chlorhexidine gluconate (CHX), Clearfil Protect Bond (CPB), and potassium-titanyl-phosphate (KTP) laser] on microleakage under metal orthodontic brackets. Sixty freshly-extracted human premolars were randomly assigned to four equal groups: group 1, 37% phosphoric acid; group 2, 37% phosphoric acid + 2% CHX; group 3, 37% phosphoric acid + KTP laser; and group 4, CPB. The teeth were kept in distilled water for 24 h, and thereafter subjected to 500 thermal cycles. Then specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned, and evaluated under a stereomicroscope. Microleakage was scored with regard to the adhesive-tooth interface and the bracket-adhesive interface at both incisal and gingival margins by the same person. Statistical analysis was accomplished by one-way ANOVA and the Kruskal-Wallis test, with significance set at p = 0.05. Microleakage was observed in all groups. No statistically significant difference was observed among all groups in terms of microleakage when bracket-adhesive and bracket-enamel interface along both gingival and incisal margins was evaluated (p > 0.05). The lowest microleakage scores were observed in the control group. CPB, KTP, and CHX groups did not show significant differences with the control group (p > 0.05), but the mean scores of the CHX group were higher than those of the other two experimental groups.

Microhardness of dentin underneath fluoride-releasing adhesive systems subjected to cariogenic challenge and fluoride therapy

The aim of this study was to evaluate the microhardness of dentin subjacent to the bonding interface of composite restorations using fluoride-releasing adhesive systems submitted to pH-cycling regimen associated or not to fluoride therapies. Thirty human third molars were prepared with class V cavities with dentin cervical margins. The adhesive systems One-Up Bond F Plus (OU), Prime&Bond NT (NT), Clearfil Protect Bond (CF), Optibond Solo Plus (OP) and also the controls [-] Single Bond 2 (SB) and [+] Ketac Molar (KM) were used previously to composite resin restorations. The restorations were sectioned into four slabs and submitted to different storage media for 15 days: distilled water, pH-cycling, pH-cycling associated to NaF 0.05% and associated to NaF 1.23%. The Knoop microhardness test was performed in dentin at 50, 100, 150 and 300 microm from the adhesive interface. Data was analyzed by three-way ANOVA and Tukey HSD test (p<0.05). KM resulted in significantly higher microhardness when compared to all the adhesive systems at 50 microm, with the exception of OU, that was similar to KM when submitted to pH-cycling alone or associated to 1.23% NaF. Microhardness of dentin was significantly higher with all the tested materials, when pH-cycling was associated to NaF 0.05%, at 50 microm and 100 microm depths. OU resulted in similar dentin hardness at all depths and storage media. The incorporation of NaF 0.05% fluoride therapy to the cariogenic challenge was capable to recover the original microhardness of dentin at 50 and 100 microm with all the tested materials.

Bond strength of different bonding systems to the lingual surface enamel of mandibular incisors

Objective: The aim of this study was to determine whether different types of adhesive systems and enamel- protective agents will affect the tensile bond strength of lingual brackets. Methods: A total of 75 extracted mandibular incisors were randomly divided into 5 groups and lingual brackets were bonded. Group 1 specimens received Transbond XT (3M Unitek, Monrovia, CA, USA), Group 2 required the application of a fluoride- releasing resin (Ortho-coat, Pulpdent, Watertown, MA, USA) with Transbond XT, Group 3 specimens received a chlorhexidine varnish (Cervitec Plus, Ivoclar Vivadent, Schaan, Lichtenstein) with Transbond XT. In Group 4, a light-cured orthodontic adhesive (Aegis Ortho, Bosworth, Skokie, USA) was applied and in Group 5, an antimicrobial self-etching primer (Clearfil Protect Bond, Kuraray, Osaka, Japan) was used. Results: There were no significant differences in bond strength whether fluoride-releasing resin or chlorhexidine varnish were used or not. Group 5 had significantly higher bond strength and adhesive remnant index (ARI) values than other groups (p ＜ 0.001). The application of enamel-protective products did not have an adverse affect on the bond strength of lingual brackets. Conclusions: These products might provide benefits both for the patient and the clinician, by supporting the oral hygiene during lingual orthodontic treatment. The higher ARI score may be beneficial for Clearfil Protect Bond but its excessive bond strength should be considered in clinical practice, especially where the enamel is thin. (Korean J Orthod 2010;40(4):260-266)

Evaluation of cytotoxicity of resin bonding materials toward human oral epithelial cells using three assay systems

Background/purpose Gingival tissue around teeth can be contacted by flowable photocured resin agents during operative procedures. The cytotoxicity of resin bonding agents toward human oral epithelial cells cannot be neglected. This study evaluates the cytotoxicity of resin bonding agents toward human oral epithelial cells using three assay systems. Materials and methods Nine commercial resin bonding agents (Clearfil Protect Bond, Clearfil SE Bond, Prime & Bond NT, Prisma Universal Bond 3, UniFil Bond, 3M Single Bond, CharmBond, Compobond, and ExciTE) and two resin monomers (methyl methacrylate and triethylene glycol dimethacrylate) were used. The detection methods for the cell survival rate included: (1) the CellTiter 96 AQueous One Solution Cell Proliferation Assay System, (2) PreMix WST-1 Cell Proliferation Assay System, and (3) CellTiter-Glo Luminescent Cell Viability Assay System. One-way analysis of variance and Scheffe test were used for the statistical analyses. Results Most of the components of the uncured bonding agents had cytotoxicity at 0.1 vol% (survival rates, 21.4% ± 1.4% to 113.1% ± 19.1%), except for UniFil Bond Primer (survival rates, 101.8% ± 3.5% to 113.1% ± 19.1%). More severe cytotoxicity was found at the 1.0 vol% concentration (survival rates, 0.2% ± 0.02% to 147.3% ± 10.8%), except for the methyl methacrylate monomer (survival rates, 96.5% ± 1.3% to 147.3% ± 10.8%). In the post-cured group, most bonding agents had little or no cytotoxicity, except for 3M Single Bond (survival rates, 52.4% ± 7.9% to 97.4% ± 17.8%) and Compobond (survival rates, 29.1% ± 7.1% to 79.5% ± 6.7%). Conclusion The same material detected by different assay systems may give different cytotoxic effects, and examination by three methods may provide more-objective results. Furthermore, since most of the bonding agent components detected by the three assay systems showed cytotoxicity before curing (and some components even showed cytotoxicity after curing), the application of bonding materials in the oral cavity should be very carefully performed.

Bracket bond strengths of new adhesive systems

Amorphous calcium phosphate, antibacterial monomer MDPB (12-methacryloyloxydodecyl-pyridinium bromide), and self-etching primers are some of the novel elements now added to bonding systems. The purpose of this study was to compare bond strengths of newer bonding systems with either bioactive components or self-etching primers with a conventional bonding system. Four new bonding systems, Aegis Ortho (with amorphous calcium phosphate) (Harry J. Bosworth, Skokie, Ill), Clearfil Protect Bond (self-etching primer with an antibacterial monomer) (Kuraray Dental, Kurashiki, Japan), iBond (reformulated self-etching primer) (Heraeus Kulzer, Hanau, Germany), and Clearfil S3 Bond (self-etching primer with combined hydrophilic and hydrophobic technology) (Kuraray Dental), were tested and compared with Transbond XT, a conventional bracket bonding system (3 M Unitek, Monrovia, Calif). Brackets bonded with these materials were tested in the shear-peel mode at 30 minutes and 24 hours, and the location of the bond failures was observed. The newer bonding systems Aegis Ortho (5.3 +/- 0.5 MPa at 30 minutes, 7.2 +/- 0.7 MPa at 24 hours), Clearfil Protect Bond (7.1 +/- 0.8 MPa at 30 minutes, 6.1 +/- 0.6 MPa at 24 hours), Clearfil S3 Bond (3.8 MPa at 30 minutes, 6.6 +/- 0.5 MPa at 24 hours), and iBond (3.9 +/- 0.4 MPa at 30 minutes, 3.9 +/- 0.3 MPa at 24 hours) achieved shear bond strengths significantly lower than Transbond XT (10.1 +/- 0.8 MPa at 30 minutes, 10.1 +/- 1.0 MPa at 24 hours). Aegis Ortho, Clearfil Protect Bond, Clearfil S3 Bond, and iBond produced lower bond strengths than did Transbond XT, with iBond's strength lower than what might be acceptable for clinical usefulness.

Bond strengths of an antibacterial monomer-containing adhesive system applied with and without acid etching for lingual retainer bonding

The aim of this study was to test the null hypothesis that there is no significant difference in bond strength and failure site location of composite bonded to etched and unetched enamel with an antibacterial monomer-containing adhesive and a conventional lingual retainer adhesive system. The crowns of 60 extracted lower human incisors were mounted in acrylic resin leaving the lingual surface of the crowns parallel to the base of the moulds. The teeth were randomly divided into three equal groups: two experimental and a control. Conventional lingual retainer composite (Transbond LR) and antibacterial monomer-containing adhesive (Clearfil Protect Bond), with or without prior etching, were applied to the lingual surface of the teeth by packing the material into cylindrical plastic matrices (Ultradent) with an internal diameter of 2.34 mm and a height of 3 mm to simulate lingual retainer bonding. The shear bond data were analysed using analysis of variance and Tukey's tests. Fracture modes were analysed by chi-square test. Statistical analysis showed that the bond strengths of the control (Transbond LR, mean: 24.77 +/- 9.25 MPa) and Clearfil Protect Bond with etching, (mean: 20.24 +/- 8.5 MPa) were significantly higher than Clearfil Protect Bond without etching, (mean: 12.56 +/- 6.93 MPa). In general, a greater percentage of the fractures were adhesive, at the tooth-composite interface (60-65 per cent). No statistically significant difference was found among the groups. The hypothesis is thus rejected. Within the limits of this in vitro model, antibacterial monomer-containing self-etch adhesive with acid etching did not significantly affect shear bond strength when compared with the control. However, the same adhesive used without acid etching resulted in a significant decrease in bond strength.

Failure rate of brackets bonded with antimicrobial and fluoride-releasing, self-etching primer and the effect on prevention of enamel demineralization

Our aim in this randomized clinical trial was to compare the failure rates of orthodontic brackets by using 2 self-etching primers (SEPs) (Transbond Plus [3M Unitek, Seefeld, Germany] and Clearfil Protect Bond [Kuraray Medical, Okayama, Japan]) with a split-mouth design. Additionally, the effect of Clearfil Protect Bond was investigated regarding inhibition of plaque accumulation and demineralization. A total of 480 brackets were bonded in 24 patients with the SEPs. The observation period was 12 months. One week after bonding and at every third recall, the plaque index and a visual rating of the enamel adjacent to the bracket were assessed at the lateral incisors and the first premolars. Additionally, DIAGNOdent (KaVo, Biberach, Germany) values were measured. Over the investigation time, 26 failures were recorded. Five occurred with the brackets bonded with Transbond Plus, and the rest with Clearfil Protect Bond (P = 0.002). The additionally observed parameters had no significant differences. The failure rate with Clearfil Protect Bond was significantly higher. For our patients, who had adequate oral hygiene, there was no benefit with regard to plaque accumulation and prevention of demineralization with Clearfil Protect Bond.

Reinforcement of dentin in self-etch adhesive technology: A new concept

Objective Characterize the ultramorphology and secondary caries inhibition potential of different dentin adhesive systems in order to find a satisfactory explanation resist to recurrent caries. Methods Human premolar dentin was treated with one of the two self-etching adhesive systems, Clearfil SE Bond, Clearfil Protect Bond or an acid-etching adhesive system, Single Bond. The bonded interface was exposed to an artificial demineralizing solution (pH 4.5) for 90 min and then 5% sodium hypochlorite for 20 min. Transmission electron microscopic observation was performed at the adhesive–dentin interface. The width of the reinforced zone was measured and data were analyzed with univariate analysis of variance under general linear model. In order to identify type of crystallites in the reinforced zone selected area electron diffraction was performed. Results An acid–base resistant zone (ABRZ) was found adjacent to the hybrid layer in the outer lesion front with only Clearfil SE Bond and Clearfil Protect Bond, while Single Bond was devoid of this protective zone. Crystallite arrangement and the ultramorphology were almost similar in the corresponding regions of Clearfil SE Bond and Clearfil Protect Bond. However, thickness of the ABRZ at the mid portion was 1159(±41.91) nm in Clearfil protect Bond, which was significantly thicker than that of Clearfil SE Bond ( F = 514.84, p < 0.001). Selected area electron diffraction confirmed the crystallites in the zone as apatite. Conclusions The self-etching adhesive systems created a new reinforced acid resistant dentin under the hybrid layer. Difference in the thickness of the zone expressed a different potential for demineralization inhibition.