Search

Introduction: The association of adhesive systems and desensitising agents could influence the values of the bond strength. That is because these desensitising agents cause the obliteration of the tubular holes and minimise the movement of the dentin fluids, promoted by environmental stimulus that tends to cause hydrolysis at the base of the hybrid layer over time. Aim: To evaluate the microtensile bond strength of total-etch (Single Bond II, SB, 3M ESPE, USA) and self-etch (Clearfil SE Bond, SE, Kuraray, Japan) adhesive systems in dentin conditioned after the application of oxalate-based and fluoride-based desensitising agents. Materials and Methods: Discs obtained from human molars were used, which had its occlusal enamel removed to expose flat surfaces of dentin. Six groups were formed, according to the materials used: G1 (control)- hybridization with SB; G2- desensitizer based on oxalate (BisBlock, BB) and SB; G3- desensitizer based on fluoride (Aqua Prep F, AF) and SB; G4 (control)- hybridization with SE; G5- BB and SE; G6- AF and SE. On these surfaces, blocks of composite resin Filtek Z350 of 5 mm high were prepared to obtain sticks of (1x1x10 mm). The samples were stored in deionized water at 37°C for 24h and submitted to microtensile mechanical trial at 1mm/min speed till the fracture. The results were statistically analysed by one-way ANOVA followed by Tukey's post hoc test (p<0.05). results: The mean values of bond strength of the studied groups in MPa (SD) were as follows: G2: 46.48 (4.02), G3: 44.87 (4.68), G5: 39.02 (4.72), G4: 36.95 (3.57), G1: 36.66 (3.42), G6: 32.71 (3.41) which did not show statistically significant differences (p>0.05). Regarding the fractures analysis, the mixed type prevailed. The fracture was on the base region of the hybrid layer for the total- etch adhesive system, and at the top of the hybrid layer for the self-etch system. conclusion: There is no significant difference in bond strength between the combined use of desensitizers with total-etch and self-etch adhesive systems on human dentine. [ABSTRACT FROM AUTHOR]

Objective and background: Different surface treatments have been tested in composite repair studies. However, there is still no consensus on the most effective repair protocol. The aim of this study is to measure the roughness values of eight different surface treatments for the repair procedure, to examine the effect of each surface treatment and three different composites on the repair bond strength with and without silane, and to evaluate whether there is a correlation between bond strength and roughness. Methods: The blocks were prepared with Filtek Z550 (3M ESPE) for the roughness measurements and divided into eight groups according to surface treatments. The roughness values of the surface treatments were measured by a 3D scanning contact profilometer (Nanomap LS). For the shear test, further samples were prepared, aged, and divided into three subgroups for the repair procedure with Filtek Z550 (3M ESPE), Vertise Flow (Kerr, USA), and G-aenial Flo (GC, Japan) after the surface treatments. Then, the shear test was performed. The Kruskal-Wallis and Spearman's Correlation tests were used for statistical evaluation of the data. Results: Significant differences were found between surface treatments and composite resins in terms of bond strength (p < 0.05). There is no correlation between the roughness and bond strength values. Conclusions: In bond strength, surface topography is more important than the numerical value of roughness. In the repair of composite restorations, methods that are already in clinical practice and more practical can be used instead of methods that require additional costs and devices. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Self-etch adhesives are well adopted in general practice, obviously primarily thanks to their ease of use and fast application time. Nevertheless, phosphoric acid is still often recommended to beforehand etch enamel following a so-called ‘selective’ enamel-etch technique, this in particular when most cavity margins end in enamel. The purpose of this study was to test if a new one-step adhesive can be applied in a multi-mode manner, this following different, either ‘full’ or ‘selective’, self-etch and etch-and-rinse approaches. Specific research hypotheses tested were that prior phosphoric-acid etching did not affect the bonding effectiveness of the one-step adhesive to enamel and dentine, and that the bonding effectiveness to dentine was also not affected when the adhesive was applied either following a ‘dry-bonding’ or ‘wet-bonding’ etch-and-rinse technique. Methods: The micro-tensile bond strength (μTBS) of the one-step self-etch adhesive G-Bond Plus (GC, Tokyo, Japan; 1-SEA) was measured when it was bonded to bur-cut enamel following either a ‘self-etch’ or an ‘etch-and-rinse’ adhesive protocol, and to bur-cut dentine when applied following either a ‘self-etch’, a ‘dry-bonding’ or a ‘wet-bonding’ etch-and-rinse adhesive protocol. Bond-strength testing was corroborated by ultra-structural analysis of the interfacial interaction at enamel and dentine using transmission electron microscopy (TEM). Results: Prior phosphoric-acid etching significantly increased the bonding effectiveness of the 1-SEA to enamel. A clearly enhanced micro-retentive surface was revealed by TEM. To dentine, no statistically significant difference in bonding effectiveness was recorded when the 1-SEA was either applied following a self-etch or both etch-and-rinse approaches. The ‘dry-bonding’ etch-and-rinse protocol was significantly more effective than its ‘wet-bonding’ version. TEM however revealed indications of low-quality hybridisation following both etch-and-rinse approaches, in particular in the form of a porous and poorly resin-infiltrated collagen mesh. Conclusions: While phosphoric-acid etching definitely improved bonding of the one-step self-etch adhesive to enamel, one should be more careful with additional phosphoric-acid etching of dentine. Although the bond strength was not reduced, the resultant adhesive interface appeared ultra-structurally more vulnerable to biodegradation. [Copyright &y& Elsevier]

Abstract: Objectives: To assess the repair potential of resin-modified glass-ionomer cements (RMGICs) with additional RMGIC and resin composite. Methods: Specimens of two proprietary RMGICs (Ketac N100 (Ketac Nano), 3M/ESPE, St Paul, MN; Fuji II LC, GC Corporation, Tokyo) were prepared and stored in water at 37°C for 4 days. The surface of the RMGIC was finished flat with 600-grit silicon carbide paper. After treatment of the original surface by either phosphoric acid or polyacrylic acid for 20s, fresh RMGIC of the same brand was added in a plastics cylinder. Untreated specimens were used as a control. Further specimens were either left untreated (control) or etched with phosphoric acid for 20s, and resin composite added. Specimens were stored in water at 37°C for 24h, and the shear bond strength measured. The fractured surfaces were examined for mode of failure. Additional RMGIC specimens were prepared for the examination of replicas of the finished and acid treated surfaces. Results: The bond strength of new Ketac N100 to old Ketac N100 was in the order of 1.7MPa, irrespective of the surface treatment, and many specimens failed before testing. The bond strength of new Fuji II LC to old Fuji II LC was in the order of 10MPa, irrespective of the surface treatment. The bond strength of resin composite bonded to both RMGICs approximated 9–16MPa. The mode of failure of the RMGIC to RMGIC bond varied depending on the products, and the mode of failure of the resin composite to RMGIC bond was predominantly cohesive in the RMGIC. SEM examination of the RMGIC surfaces showed little effect from acid treatment. Significance: Based on this laboratory study, repair of RMGIC with additional RMGIC maybe clinically unpredictable, depending on the products used; repair with resin composite appears to be the preferred option. [Copyright &y& Elsevier]

This study was undertaken to evaluate the two-year clinical performance of a self-etching primer and a serf-etching adhesive, both of which employ the same acidic monomer. Forty pairs of restorations of AP-X hybrid resin composite (Kuraray Co, Ltd, Osaka, Japan) were placed in caries-free cervical erosion/abfraction lesions. Based on insensitivity to air, the dentin in 62% of these lesions was considered to be sclerotic. The restorations were placed with no abrasion of tooth surfaces, except for cleaning with plain pumice and no use of phosphoric acid etching, which is counter to the manufacturer's instructions that call for etching of unprepared enamel. One restoration from each pair was placed using Clearfil SE Bond, an adhesive employing a self-etching primer, and the other was placed using Clearfil S³ Bond, a self-etching adhesive. To emulate the results likely to occur in a private practice, the restorations were placed by well-educated, experienced clinicians who had no particular expertise in adhesive dentistry research and who placed the restorations according only to their interpretation of the manufacturer's instructions. The restorations were clinically evaluated at baseline and at 6, 12 and 24 months, using modified Ryge/USPHS criteria. For both products, retention of 81%-84% of the restorations was observed over two years, which is lower than has been previously observed with these products and is likely due to limitations in the manufacturer's instructions compounded by inexperience of the operators in adhesive dentistry research. One restoration placed with each adhesive demonstrated secondary caries, which was probably attributable to the study being conducted in a non-fluoridated area and which reduced the percentages of clinically successful restorations to 78%-81%. No statistically significant difference (p=0.50) between the two adhesives was observed in overall performance. [ABSTRACT FROM AUTHOR]

The article discusses the difficulty of finding new substitute for gold-silver-palladium alloys that can be used in dental treatment in Japan. It states that gold-silver-palladium alloys are used for crown-bridges, inlays, and retainers of removal partial dentures based on the Japanese Social Insurance System, however, the sudden rise of its prices have prompted experts to seek for options. However, it notes the difficulty of the experts to find new option for gold-silver-palladium alloys.

This study examined the relationship between the bond agent application duration and the dentin bond strength of several single-application bonding systems. The restorative material/bonding systems used were Reactmer, with its single-application bonding system Reactmer Bond (RB, Shofu Inc, Kyoto, Japan); Palqifue Estelite, with its single-application bonding system One-Up Bond F (OU, Tokuyama Co, Tokyo, Japan) and F2000 Compomer, with its bonding system Primer/Adhesive in Clicker (F2, 3M Dental Products, St Paul, MN 55144, USA). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600SiC to expose labial dentin. Adhesives were applied for 5, 10, 20, 30 and 60 seconds, and reetorative materials were condensed into a Teflon mold (Ø4 x 2 mm) on the dentin and light activated. Fifteen samples per test group were stored in 37°C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Duncan test (p=0.05) was done. SEM observations of the treated dentin surface were also conducted, the dentin bond strength ranged from 6.9 ± 2.4 to 11.2 ± 2.8 MPa for RB, 8.9 ± 2.2 to 12.2 ± 1.9 MPa for OU, and 7.8 ± 3.1 to 11.4 ± 2.6 MPa for F2. No significant differences were found among the 10-60 second application duration groups for the systems used. From the SEM observations, demineralization of the dentin surface was more pronounced with longer application duration. The data suggest that the duration of single-application bonding systems was not a crucial factor for determining dentin bond strength, even though morphological changes were observed on the dentin surface. [ABSTRACT FROM AUTHOR]

The article discusses a study conducted by Japanese researchers which investigates the impact of various surface treatments on CerAdapt, a ceramic abutment from Nobel Biocare AB, for shear bond strength. Findings of the study reveal that the highest adhesion strength was achieved using the sandblasting treatment with phosphoric acid, aluminum oxide and hydrofluoric acid. However, it indicates that the latter's utilization for 120 seconds could reduce substantially the control's bond strength.

Background: The bond strength of resin composites to dentin was reported to be related to either the remaining dentin thickness (RDT) or bleaching treatment. However, information is limited regarding the effects of RDT on the bond strength of bleached dentin. The present study aimed to investigate the effects of RDT on the microshear bond strength (μSBS) of resin cement to bleached dentin., Methods: A total of 120 dentin specimens were prepared and randomly divided into 2 groups: a bleaching group (group B) and a control group (group C). Hydrogen peroxide with a concentration of 35% (Ultradent, USA) was applied on the dentin surface for 2 × 1 d for group B, while no bleaching treatment was performed for group C. After the treatment, the specimens were finished and polished to obtain different RDTs (2, 1, and 0.5 mm) and divided into 3 groups of 20 specimens each. The bonding procedure was performed using Panavia V5 (Kuraray, Japan) with a bonding area of 0.785 mm 2 . For each group, half of the specimens were subjected to 5000 thermal cycles (subgroup T), while the other half did not receive thermocycling (subgroup N) (n = 10). The specimens were then subjected to the μSBS test using a universal testing machine. Data were analyzed by a three-way analysis of variance (α = 0.05). The fracture modes of the specimens were confirmed with a measuring microscope. Representative specimens with different fracture modes were observed with scanning electron microscopy (SEM)., Results: The μSBS values were significantly affected by bleaching treatment (p < 0.001), whereas no significant effect was observed for thermocycling (p = 0.293). In terms of RDT, a significantly different μSBS value was found among the subgroups with different RDTs in group C (p = 0.003). However, the RDT did not significantly affect the μSBS values of bleached dentin in group B (p = 0.779). The μSBS values were significantly lower in group B than in group C (p < 0.001). A higher percentage of adhesive failure was observed in group B than in group C., Conclusion: Based on the present findings, it can be concluded that the RDT did not affect the bond strength of resin cement to bleached dentin., Clinical Significance: Since RDT did not affect the bond strength of resin cement to bleached dentin, bonding procedures should not be performed immediately after intracoronal bleaching, even if the dentin is planned to be removed due to a tooth preparation process.

Objectives: The efficacy of using a 45S5 Bioglass paste as a remineralizing temporary filling material was compared to fluoride gel (1.23% acidulated-phosphate-fluoride, Gelato Gel, NJ, USA) applied for 24 h and for 4 min and to a temporary filling material (Caviton; GC, Tokyo, Japan)., Methods: 66 extracted human premolars were used. All specimens were sectioned mesio-distally. All specimens were challenged by a demineralization solution (pH4.5) for 4 days. The specimens were divided into 4 groups: (Bioglass), (Fluoride 4-minutes), (Fluoride 24-Hours), and (Temp) (n = 33). 10 specimens were examined by TMR (Transversal Microradiography)to test remineralization capacity of each agent. 8 specimens were assigned to determine the acid resistance of a bonded resin-enamel interface after the various treatment methods. 15 samples were assigned to determine the effect of each agent on the shear bond strength of a single bottle self-etch adhesive system. One way ANOVA was used to compare the obtained results (p < 0.05)., Results: Specimens treated with 45S5 bioglass showed statistically significant reductions in (delta z) values when compared to the other three groups (p < 0.05). Treatment of demineralized enamel by fluoride prior to bonding significantly decreased shear bond strength values, however 45S5 bioglass treatment did not affect the shear bond strength of adhesive system to enamel (p < 0.05). The acid-resistance of the interface between resin-enamel was significantly improved when fluoride or bioglass were applied onto the enamel surface prior to demineralization., Conclusions: 45S5 bioglass paste has high potential to be used as a remineralizing temporary filling material., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The aim of the study is to assess the clinical effect of an antibacterial monomer-containing primer on preventing white spot lesions (WSLs) during fixed orthodontic treatment., Subject and Methods: The study included 35 patients. A split-mouth design was used during bonding of the brackets. In Clearfil (CF) group, adhesive-coated brackets (APC Plus Victory series, 3M Unitek, Monrovia, CA, USA) were bonded with an antibacterial monomer-containing primer (Clearfil Protect Bond, Kuraray Medical, Okayama, Japan). In Transbond (TB) group, the same adhesive-coated brackets were bonded using a conventional primer (Transbond XT Primer; 3M Unitek, Monrovia, CA, USA). The mean duration of orthodontic treatment was 16 months. Digital images of each tooth were used to assess the WSLs. The areas of the WSLs were measured with a software. The bond failures during orthodontic treatment were also recorded., Results: After fixed orthodontic treatment, 23 of the 35 patients showed one or more WSLs. Of the total of 666 teeth, 114 WSLs occurred over the orthodontic treatment time. Rates of WSL in the CF and TB groups were 8.03% and 9.24%, respectively. The difference in WSL rates between the two groups was not statistically significant. No significant difference was observed in the lesion areas between the groups. Moreover, the difference in bracket failure rates between the two groups was also not statistically significant., Conclusion: The results of this long-term clinical study indicated no significant difference between the antibacterial monomer-containing primer group and the control group in the efficacy of reducing demineralization throughout the orthodontic treatment.

Despite improvements in dental adhesive materials, internal adaptation remains a challenge in bonded restorations. The aim of this study was to compare microgaps and internal floor adaptation between two different self-etch adhesives in class-V cavities using cross-polarization optical coherence tomography (CP-OCT). In this in vitro study, standardized round class-V cavities were prepared in 20 non-carious human upper central incisor teeth. They were randomly divided into two groups, TN and SE, with each group receiving a different dental adhesive. In TN group, the adhesive used was all-in-one Tetric N-Bond Self-Etch (TN; Ivoclar/Vivadent, Liechtenstein), while SE group was bonded with two-step self-etch Clearfil SE Bond 2 adhesive (SE; Kuraray Noritake Dental Inc, Japan). The prepared cavities were restored with flowable composite and then stored in distilled water for 24 h. Next, they were immersed in silver nitrate, followed by immersion in a photo-developing solution. Optical comparison was carried out by CP-OCT to assess microgaps and composite adaptation at the cavity floor. A Mann-Whitney test was applied to the data, which showed a statistically significant difference in composite adaptation among the two groups (p < 0.001) with the SE group showing superior adaptation. CP-OCT is a reliable tool for non-invasive imaging that gives an insight into composite performance. Better adaptation was found with the two-step self-adhesive for the composite used in this study.

Objective: To evaluate the influence of saliva contamination and cleaning procedures on shear bond strength (SBS) of a self-adhesive resin cement (SAC) to zirconia surfaces., Materials and Methods: A total of 160 sandblasted zirconia blocks were randomly divided into eight groups as follows: No saliva contamination, no cleansing (NC-NC); contamination with saliva, no cleansing (SC-NC); no saliva contamination, cleansing with a zirconia primer (ZP; Z-Bond, Danville Materials, Inc., S. Ramon, California) (NC-ZP); contamination with saliva, cleansing with ZP (SC-ZP); no saliva contamination, cleansing with hydrofluoric acid (HF; Ultradent Porcelain Etch; Ultradent Products, South Jordan, Utah) followed by cleansing with ZP (NC-HF-ZP); contamination with saliva, cleansing with HF followed by cleansing with ZP (SC-HF-ZP); cleansing with ZP, contamination with saliva, cleansing with ZP (ZP-SC-ZP); application of ZP, contamination with saliva, cleansing with HF followed by cleansing with ZP (ZP-SC-HF-ZP). Cylindrical resin composite blocks were luted to the zirconia surfaces with SAC (Clearfil SA Cement Automix, Kuraray, Inc., Tokyo, Japan). Specimens were subjected to shear forces at a cross-head speed of 0.5 mm/min. Data were analyzed with Analysis of Variance and Tukey tests (α = 0.05)., Results: The bond strength values to zirconia were significantly influenced by saliva contamination (P < .05). The SC-NC group showed the lowest bond strength values (5.6 ± 1.4 MPa; P < .05). All cleansing or pretreatment agents improved the bond strengths when compared to noncleansing groups, NC-NC and SC-NC., Conclusion: In situations where saliva contamination is deemed unavoidable, application of ZP after try-in of the zirconia restoration could be beneficial for the accurate cementation., Clinical Significance: During try-in sessions of fixed dental prostheses, zirconia ceramic restoration may come into contact with saliva and surfaces should be cleansed to obtain an optimal surface for adhesion. Application of zirconia primer to the sandblasted zirconia surface is recommended whether the surface is contaminated with saliva or not., (© 2018 Wiley Periodicals, Inc.)

Adhesive test in vitro is performed to evaluate bonding materials. This paper describes methods of measuring adhesion to dentine currently used in Japan, and considers advantages and disadvantages. Various tests are used in Japan. Many factors-dentine substrate, storage conditions, bond strength test method-affect bonding to dentine. Bond strength test methods employed are divided into: tensile bond test and shear bond test. The test method used for the best prediction of clinical performance in bond strength evaluation is discussed. There has also been interest in bonding stability. At present, it may be difficult to propose an optimal standardized measuring method. Standardized experimental conditions in vitro which can simulate conditions in vivo are still under investigation.

Monomers which promote adhesion not only to enamel but also to dentine have been prepared. They have both hydrophilic and hydrophobic groups. The monomers are 2-hydroxy-3-beta-naphthoxypropyl methacrylate, 2-methacryloxyethyl phenyl hydrogen phosphoric acid and 4-methacryloxyethyl trimellitate anhydride. Chemical reaction between monomers and tooth substrates did not lead to adhesion. Cleaning of the ground tooth surface to remove the smeared layer with aqueous 10 per cent citric acid and 3 per cent ferric chloride solution prior to adhesion is recommended. Then, the lipophilic monomers will promote the inter-penetration of monomers into the hard tissues. The infiltrated methacrylates polymerize there and good adhesion takes place. The layer has good resistance against acid and is, in effect, a resin reinforced dentine and enamel as demonstrated by SEM and TEM. The tensile adhesive strength to the cleaned dentine was 18 MN/m2 and to the enamel 14 MN/m2. On the other hand, the value was reduced to 6 MN/m2 when the dentine had been etched by phosphoric acid or citric acid. The ferric chloride added to the citric acid protected dentinal collagen during demineralization. However, the ferric chloride provided ineffective protection against an acid as strong as phosphoric acid. The high bond strength was not dependent upon interlocking at the dentinal tubules as had been considered previously. The resin reinforced dentine and enamel is a hybrid of natural tissue and artificial material and is valuable in the prevention of secondary caries after restoration.