Search

Copyright of West China Journal of Stomatology is the property of Sichuan University, West China College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nanomaterials usually refer to tiny particles with a diameter of 1-100 nm, which often have unique physicochemical properties and are one of the main areas of research interest for development of dental biomaterials. Nano-calcium phosphate modified dental materials have been widely used in pit and fissure sealing, dental resin restoration, tooth adhesion, and root canal sealing. The current research shows that the dental material modified by nano-calcium phosphate has stronger mechanical properties and shows long-term calcium and phosphorus ion release and excellent ion recharging ability, which can promote the remineralization of tooth hard tissue and has good prospects for application. However, it is difficult to accurately simulate the complex environment of the oral cavity. Therefore, the biocompatibility, cytotoxicity and effect of clinical application of nano-calcium phosphate modified dental materials still needs further study. This review summarizes and discusses the recent research progress regarding nano-calcium phosphate modified dental materials in the prevention and treatment of dental pulp diseases.

This study aimed to evaluate the effect of three pretreatment conditioners and surface preparations on a composite resin adhesive for a gold alloy. Cast disk specimens were made and bonded with RelyX Unicem luting agent under six surface conditions: 1) polished with No.600 carbide paper, 2) air-abraded with alumina, 3) Alloy Primer metal conditioner was applied after alumina-abrasion, 4) Monobond Plus multipurpose conditioner was applied after alumina-abrasion, 5) M. L. Primer metal conditioner was applied after alumina-abrasion, and 6) Rocatec multipurpose silica-coating system was applied. The bond strengths were determined before and after thermocycling (50,000 cycles). The bond strengths of the alumina-abrasion group were significantly decreased after thermocycling. The Rocatec and M. L. Primer exhibited higher bond strengths than other treatments. The application of metal conditioners and multipurpose surface preparations was recommended for improved bonding between the evaluated adhesive resin and gold alloy. [ABSTRACT FROM AUTHOR]

BACKGROUND: There are many studies on the marginal integrity of all ceramic crowns with different resin adhesives, or different shoulder, different polymerization angles, but there is no research on whether different methods of redundant bonding will affect the marginal integrity of all ceramic crowns. OBJECTIVE: To analyze the effect of removing excess resin adhesive on the marginal integrity of all ceramic crowns with different marginal gaps. METHODS: Totally 40 extracted third molars were prepared with all ceramic crowns and randomly divided into groups A, B, C, and D (10 teeth in each group). After the model scanning was completed, the edges of restoration in groups A, B and C were lifted at 30, 60 and 90 µm respectively by computer control, while those in group D were not raised. Procera alumina CAD-CAM all ceramic crowns were made. Then, the four groups of groups A, B, C and D were randomly divided into two subgroups. In one subgroup, a large amount of excess resin adhesive was removed with a small brush, and then the light was illuminated for 40 seconds after the full crown bonding. Subsequently, a small amount of resin adhesive was scraped off with sickle scalpel (small brush group). The sample in the other subgroup was exposed to light for 2 seconds, scraped off with sickle scalpel, and then illuminated for 40 seconds (sickle group). The marginal integrity and surface quality of the adhesive were observed by scanning electron microscope. RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that the continuity of the bonding interface was better in the small brush group. Different degrees of adhesive defects were found in the sickle group. Under the same marginal gap, the defect rate of cement in the small brush group was lower than that in the sickle group (P < 0.05). Under the same adhesive removal method, there was no significant difference in the defect rate of cement between groups A, B, C, and D (P > 0.05). (2) Results indicate that the method of using small brush to remove excess adhesive, then lighting for 40 seconds, and finally using sickle scalpel to remove the remaining small amount of adhesive is more suitable for clinical practice. [ABSTRACT FROM AUTHOR]

Hydrolytic and enzymatic degradation of resin adhesives over time has been mainly attributed to secondary caries formation of methacrylate-based tooth-colored resin-based composite restorations. Ability of resin adhesive monomers to infiltrate into demineralized dentin forming stiff polymer matrix and potentially bonding to tooth structure is also a crucial property. The only commercially available antibacterial monomer, 12-methacryloyloxydodecyl pyridinium bromide (MDPB), is a quaternary ammonium methacrylate. This methacrylate monomer undergoes hydrolytic degradation, and could not bond to tooth structure. In this study, a new hydrolytic resistant monomer HMTAF was synthesized. It is methacrylamide-based monomer that, unlike methacrylate, is highly resistant to hydrolysis. Its molecular structure has particular functional groups; quaternary ammonium fluoride salt with potential antibacterial fluoride-releasing activity, hydroxyl and amide group with hydrogen bonding potential to dentin collagen. Hydroxyl group also increases monomer hydrophilicity for better penetration into water-saturated dentin and sufficient resin-dentin bond. The synthesized HMTAF and its polymer showed no hydrolytic degradation in acidic environment, while MDPB and its polymer were partially decomposed under this challenge. The conversion of monomer HMTAF to polymer was illustrated by FT-IR. The results indicated that HMTAF is highly resistant to hydrolysis, polymerizable and non-cytotoxic to Vero cell lines. It is a potential monomer to be incorporated into resin adhesives for improving hydrolytic and enzymatic resistance.

Adhesives have been used by mankind for several millennia. Initially used in the creation of tools and hunting weapons, they can nowadays be found in almost all branches of industry and everyday life. This article presents three experiments on some of the most ancient adhesives: birch pitch, resin adhesives, and animal glue. They can be conducted in chemistry and science classes of secondary and primary schools and especially in school science clubs or projects in order to discuss intermolecular interactions. In addition to the experiments, this article gives an illustration of the physicochemical and historical background of adhesives. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate 2 thione primers and 3 resin adhesives for enhancement of bonding strength to a silver-palladium-copper-gold alloy. Method and Materials: Two different sized disk specimens (10- and 8-mm diameter by 2.5-mm thick) were prepared from a silver-palladium-copper-gold alloy (Castwell MC. 12, GC). The specimens were airborne-particle abraded with 50-μm-grain alumina, conditioned either with a thiouracil primer (Metaltite, Tokuyama Dental) or with a triazine dithione primer (V-Primer, Sun Medical), and then bonded with 1 of 3 acrylic resins: a benzoyl peroxide-amine redox-initiated resin adhesive (Multi-Bond, Tokuyama Dental) or a tri-n-butylborane-initiated resin adhesive (Super-Bond C&B and Super-Bond Quick, Sun Medical). For each adhesive, unprimed specimens were prepared as experimental controls. Shear bond strength was determined after thermocycling (100,000 cycles). Results: Use of primers significantly (P < .05) enhanced the bond strength of specimens in all adhesives. Irrespective of the type of primer, the strength of Multi-Bond adhesive was significantly (P < .05) lower than that of Super-Bond C&B and Super-Bond Quick adhesives. The strength of the 2 tri-n-butylborane-initiated adhesives did not differ significantly (P> .05). The mean strength of the Super-Bond C&B adhesive was 40.4 MPa with Metaltite and 37.8 MPa with V-Primer; that of Super-Bond Quick adhesive was 40.9 MPa with Metaltite and 36.5 MPa with V-Primer. Conclusion: Use of thione primers effectively enhanced the strength of the bond to the silver-palladium-copper-gold alloy. Furthermore, the combinations of primers and tri-n-butylborane-initiated adhesives were found to be more efficient for bonding. [ABSTRACT FROM AUTHOR]

Hydrolytic and enzymatic degradation of resin adhesives over time has been mainly attributed to secondary caries formation of methacrylate-based tooth-colored resin-based composite restorations. Ability of resin adhesive monomers to infiltrate into demineralized dentin forming stiff polymer matrix and potentially bonding to tooth structure is also a crucial property. The only commercially available antibacterial monomer, 12-methacryloyloxydodecyl pyridinium bromide (MDPB), is a quaternary ammonium methacrylate. This methacrylate monomer undergoes hydrolytic degradation, and could not bond to tooth structure. In this study, a new hydrolytic resistant monomer HMTAF was synthesized. It is methacrylamide-based monomer that, unlike methacrylate, is highly resistant to hydrolysis. Its molecular structure has particular functional groups; quaternary ammonium fluoride salt with potential antibacterial fluoride-releasing activity, hydroxyl and amide group with hydrogen bonding potential to dentin collagen. Hydroxyl group also increases monomer hydrophilicity for better penetration into water-saturated dentin and sufficient resin-dentin bond. The synthesized HMTAF and its polymer showed no hydrolytic degradation in acidic environment, while MDPB and its polymer were partially decomposed under this challenge. The conversion of monomer HMTAF to polymer was illustrated by FT-IR. The results indicated that HMTAF is highly resistant to hydrolysis, polymerizable and non-cytotoxic to Vero cell lines. It is a potential monomer to be incorporated into resin adhesives for improving hydrolytic and enzymatic resistance. [ABSTRACT FROM AUTHOR]

• Pull-out fire tests on bonded anchors for ISO 843-1 fire. • Bond strength vs. time curve using resistance integration method based on fire tests. • Thermal investigation parameter of pull-out fire tests in the current guidelines. • Analysis of the predicted bond resistance for each parameter. This paper aims to experimentally apply the existing method for evaluating the pull-out capacity of mechanical anchors under fire, to bonded anchors. Due to the absence of sufficient guidelines for evaluating bonded anchors directly exposed to fire, this experimental work studies the influence of the existing evaluation method on the prediction of the bond resistance and failure time. Different testing conditions and possible configurations for anchors in buildings are explored. The studied influencing parameters are: presence of fixtures, insulation of fixtures, thickness of the concrete bearing element, diameter of the anchor, concrete/steel temperature. The influence of each parameter on the predicted bond resistance and failure time, determined with a design method based on resistance integration is studied. Results show that parameters such as concrete element thickness and attaching metallic fixtures on anchors have a negligible influence on the predicted load-bearing capacity and failure time. However, adopting concrete temperature instead of anchor steel temperature in the resistance integration method, and putting insulation around fixtures may lead to a false estimation of the load-bearing capacity and failure time. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the effect of graphene oxide (GO) nano-filler content in experimental dental adhesive on its degree of conversion (DC), microtensile bond strength ( μ TBS) and structural reliability, using Fourier transform infrared spectroscopy (FTIR), Micro-Raman spectroscopy and Scanning electron microscopy (SEM). A resin adhesive was fabricated (control adhesive - CA) and fabricated GO nano-particles were added at 0.5% and 2.0% (m/m) to produce adhesives GOA1 and GOA2 respectively. One hundred and two teeth (specimens) were prepared for dentin exposure and conditioned with 36% phosphoric acid. Specimens in each group (n = 34) were treated with formulated adhesives (CA, GOA1 & GOA2) and photo-polymerized for 20 s followed by composite build up. Sixty specimens were used for μ TBS testing in the adhesive groups (CA, GOA1 & GOA2), with half exposed to thermocycling (TC) whereas the remaining half (n = 10) stored in distilled water. Seven specimens each were assessed using SEM and Micro-Raman spectroscopy, in each adhesive group (n = 7). DC for the adhesives was assessed using FTIR. The means of μ TBS and DC were analyzed using ANOVA and post hoc Tukey multiple comparisons test. GO nano-filler content showed significant influence on the adhesive μ TBS in comparison to controls (p < 0.01). Ageing (TC) revealed significant reduction in the μ TBS, except in GOA2 specimens, which showed comparable outcomes among TC and non-TC specimens (p > 0.05). DC was significantly higher in control adhesive [46.8 (3.6)%] compared to GOA2 [37.7 (4.2)%] specimens, however DC was comparable among GOA1 [42.3 (2.9)%] and GOA2 [37.7 (4.2)%] specimens (p > 0.05) respectively. GO exhibited interaction within adhesive and tooth dentin comparable to control adhesive. Increasing GO content showed increase in μ TBS of adhesive to dentin, but a decrease in degree of conversion. Under ideal conditions, experimental adhesive with 2% GO content showed acceptable bond strength and DC; and should be further assessed under dynamic conditions to recommend clinical use.

Statement of Problem: There is no enough published data about the shear bond strength of resin modified glass ionomer adhesives on caries-affected primary tooth dentin excavated using minimally invasive systems. Objectives: To evaluate the shear bond strength of 2 different adhesives (one resin modified glass ionomer and one resin) using two caries removal tech- niques on healthy and caries-affected primary dentin. Materials and Methods: Two caries removal methods including mechanical (handpiece) and chemomechanical (Carisolv) techniques and two types of ad- hesives including one resin adhesive (Clearfil SE Bond; CSEB, Kuraray) and one resin-modified glass ionomer adhesive (Riva Bond LC; RBLC, SDI) were used in this study. Ten extracted healthy primary teeth were used for the control group. The teeth were sectioned bucco-lingually and mesio-distally in order to obtain four specimens from each tooth. Thirty suitable specimens were selected as the “control” and randomly divided into two groups of “sound dentin” based on the type of the adhesive used. Sixty extracted caries affected teeth were used for the carious group; sectioned as mentioned above and sixty suitable specimens were selected as the “treatment”. Then the specimens were arbitrarily divided into four groups based on caries removal techniques and the type of ad- hesive used (n = 15). After bonding with either CSEB or RBLC, the specimens were restored with a resin composite by means of PVC tubes and subjected to the shear bond strength test. The data was analyzed using ANOVA and Tukey’s test. Results: The specimens in Carisolv group bonded with CSEB (11.68 ± 3.1) showed a statistically significant higher mean bond strength followed by those in handpiece group bonded with CSEB (9.4 ± 2.7), which exhibited higher mean values than those groups with RBLC (p < 0.05). Shear bond strength values for Clearfil SE Bond was not significantly higher than Riva Bond LC when used in sound dentin. Conclusions: The lowest shear bond strengths for both adhesives were observed on caries-free dentin.

The aim of this research is to see the effect of various dentin conditioners (phosphoric acid) to the bond strength between resin adhesive HNPM/TEGDMA (2 Hydroxy-3,2-Napthoxy-Propyl Methacrylate/Trietilen Glokol di Methacrylate) and dentin tissue of bovine teeth. Dentin conditioner that was used are phosphoric acid solution 10% 25%, 35% (Group A1, A2, A3). Specimens was divided into 3 groups, each group has 10 specimens. Bond strength test used "Universal Testing Machine" AG 5000 and SHIMADZU type. The result of this research shows average differences of bond strength of each group. Anova test there is a significant difference (8.545 and p2 and A3 group. The result of the research stated there are effects of various dentin conditioners to the bond strength between resin adhesive HNPM/TEGDMA and dentin tissue.

Abstract Background/purpose The longevity of bonded composite restorations could be affected by the utilized adhesive-composite application techniques. This in vitro study aimed to evaluate the influence of adhesive-composite application modalities on their bonding values to tooth structure and on the failure resistance of the performed restorations on loading. Materials and methods Resin composite studs, 2 mm in diameter and 4 mm high, were bonded in 2 groups to flattened enamel and dentin surfaces of 80 extracted premolars using pre-cured (PC) and co-cured (CC) self-etch resin adhesive. Studs in each group were built-up in 4 subgroups using either multiple increments of nano-filled composite (IF, control) or single increment of preheated nano-filled (PH), bulk-fill (BF) and sonic-activated bulk-fill composites (SF). Another 80 premolars with standard class II cavities were also restored using the same adhesive-composite application modalities. All specimens were then stressed on a universal testing machine to assess the composite-tooth shear bond strength and the resistance of the performed restorations to failure. The modes of specimens' failure were also assessed following each test. Results The PC adhesive provided higher bond strength to dentin (p < 0.05) and comparable bond strength to enamel in comparison to the CC one (p>0.05%). Both PH and BF composites showed lower bond strength to dentin in presence of PC adhesive (p < 0.05). Comparable bond strengths were noticed for PH, BF and SF composites to dentin in presence of CC adhesive (p > 0.05). PH and SF restorations presented the highest resistance to failure (p < 0.05). Conclusion Both incrementally and bulky-inserted composites offer clinically acceptable bond strength in presence of pre-cured resin adhesive. Both Preheated and sonic-activated composite restorations offer the highest resistance to failure on loading. The preheating procedure renders regular composite material suitable for bulk-fill applications. [ABSTRACT FROM AUTHOR]

Objective: The shear strength of three resin adhesives and pure alumina veneers was determined by sandblasting, silica hydrothermal heat treatment and silane coupling agent. After the surface treatment, the shear strength of three kinds of resin adhesives and pure alumina was determined. Methods: Thirty cases of the high purity α-Al2O3 pure alumina specimens were randomly divided into three groups: group A（SACTM resin adhesive）, group B（Vorilink N resin adhesive）, group C（RelyXTM Unicem adhesive）, with 10 cases in each group. After bonding with the specimen, the shear adhesive strength was tested after incubation at 37 ℃ for 24 hours. The failure modes of the bonding interface of each specimen were observed under scanning electron microscope. Results: The bonding strength of SAC resin adhesive was（25.91±2.97）, which was the highest in the hree kinds of resin adhesives（P<0.05） and was higher than that of Vorilink N（18.37±2.11） and RelyXTM Unicem was（9.98±1.22）（P<0.05）. Group A was mixed for all, Group B had internal damage to the adhesive. Group C had both damage and interface damage and internal damage of the adhesive. Scanning electron microscopy showed that there were many resin residues in the adhesive cross section of group A and B, the residual resin on group C was few. Conclusion: Different resin adhesives had an effect on the bonding strength of pure alumina specimens. The SACTM adhesive had the best bonding effect. [ABSTRACT FROM AUTHOR]

The 12-methacryloxydodecylpyridium bromide (MDPB) has been reported to act as a matrix metalloprotease (MMP) inhibitor. In this study, the effects of application of MDPB on resin-dentin bonds were evaluated. The resin-dentin bonded specimens were prepared with a commercial MDPB-containing self-etching primer or a self-etching primer without MDPB, and stored 24 h or 1 year. Surfaces were pretreated with chlorhexidine or MDPB-containing cavity disinfectant. Additionally, we compared the degradation patterns between the two self-etching adhesives and etch and rinse system. Water tree formations were observed as the typical morphological phase of the two tested self-etching adhesives for both 24 h and 1 year groups. The degradation phase of collagen network depletion was observed in the adhesive interface of the etch-and-rinse system in the 1 year group. Pretreatment with chlorhexidine did not prevent bond strength reduction after 1 year. The cavity disinfectant improved the bond durability for the self-etching adhesive. [ABSTRACT FROM AUTHOR]

Resin–dentin bonding was first achieved through mechanical hybridization between resin and collagen fibrils using a functional monomer containing resin system. In the last decade, new adhesive resin systems were frequently released onto the market within a short-period of time. Before and after commercialization, the bond integrity has been tested by bond tests, and leakage evaluation by researchers, but it is very difficult for clinicians to obtain a comprehensive, up-to-date understanding of their nature and degradation. Although newly developed adhesive resins have attempted to improve the bond strength at least in the first 24 h after bonding, the long-term durability of the bonds has not yet been established analytically. However, numerous recent studies have shown micromorphological evidence of biodegradation of resin–dentin bonds, due to hydrolysis of the resin and collagen fibrils within the bonds. This review mainly summarizes the most recent work in biodegradation of resin–dentin bonds based on micromorphological analyses of data obtained by scanning and transmission electron microscopy.

Objectives: The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment., Methods: Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically., Results: After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease ( P >0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease ( P <0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease ( P >0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved ( P >0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling ( P <0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling ( P >0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling ( P <0.05)., Conclusions: The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.

Copyright of West China Journal of Stomatology is the property of Sichuan University, West China College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The purpose of this study was to evaluate the clinical performance of resin-bonded fixed partial dental prostheses (RBFPDPs) made with metal alloys. Materials and methods: The retention of 311 RBFPDPs from 226 patients fabricated from 1983 to 2013 using an adhesive resin was clinically evaluated. Partial or complete debonding of the RBFPDP or framework fracture was considered a treatment failure. All data were obtained from clinical examinations, and missing data were censored at the date of the last available information. The effect of the following factors on survival rate were investigated: patient gender, location (maxilla/mandible and anterior/posterior), number of missing teeth, number of abutment teeth, framework structure, type of metal alloy, patient age at the point of cementation, cement type, and distinction of the treating dentist. Data were analyzed with the Kaplan-Meier survival tests, log-rank tests, and Cox regression analyses ( α = 0.05). Results: The Kaplan-Meier survival rate was 41.2 % ± 6.5 % (standard error) at 28.8 years (last outcome event). Significant differences were found for patient age and treating dentist ( p < 0.05). The risk of failure in younger patients was 1.7 times greater than that in older patients and that of inexperienced dentists was 2.0 times greater than that of dentist experienced and specialized in adhesive dentistry. Conclusions: When fabricating RBFPDPs for younger patients, mechanical preparation for bonding may be necessary in consideration of the risk for debonding. Experienced dentists may achieve better results. Clinical relevance: Mastery of skills is necessary to ensure excellent prognoses for RBFPDPs. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating the remineralizing properties of three experimental light-curable resin-based dental adhesives containing tailored polycarboxylated microfillers. A co-monomers blend was firstly formulated and then mixed with each of the following microfillers: polycarboxylated bioactive glass (PBAG), polycarboxylated calcium silicates (PCS), and polycarboxylated calcium silicates-doped brushite (PDP). The three experimental and a filler-free control resins were applied onto 10% orthophosphoric acid treated dentin discs and light cured. The specimens were soaked in artificial saliva (AS) for 3, 7, and 14 days. Dentin mineral variation was monitored using attenuated total reflection-Fourier transform infrared (ATR-FTIR) and Raman spectroscopy. Confocal laser scanning microscopy (CLSM) was employed to observe the ultra-morphology/nanoleakage along the resindentin interface. The bonding ability and the durability of the resin-dentin bonds were investigated through microtensile bond strength (μTBS) test. ATR-FTIR and Raman showed a significant increase of the mineral matrix area ratio and phosphate peak intensity in specimens treated with the experimental resins within 14 days (p<0.05). No significant increment of minerals was found in untreated specimens or specimens treated using the control filler-free resin (p>0.05). Dentin treated using PBAG or PCS exhibited higher level of remineralization than the specimens in PDP group. CLSM showed reduction in nanoleakage, although the remineralization of the hybrid layer induced a significant drop in the μTBS after 3-month storage (p<0.05). The experimental resin-based dental adhesives containing bioactive microfillers remineralize the resin-dentin interfaces when in intimate contact with biological fluids. [ABSTRACT FROM AUTHOR]

Abstract: The objectives of this study were to identify the effect of design parameters, namely marginal thickness, degree of convergence and the different interfacial conditions, on the initial failure load that induces cracking from the margin in glass-simulated dental crowns. Crown-like glass cylinders were prepared to simulate posterior all-ceramic crowns with two different marginal thicknesses (0.8 or 1.2mm) and degrees of convergence (6° or 12°). A three-step bonding system was used complementarily with a silane coupling agent to adhesively bond the specimens to resin dies. The crowns were subjected to an axial applied load to generate hoop tensile stress at the crown margin. The entire loading and fracture processes were recorded by video camera. The loading data were compared with the other two interfacial treatments (Vaseline grease and directly poured uncured resin on glass). The Weibull distribution was used to statistically analyze the characteristic failure load and the mean values. The fracture surfaces were fractographically analyzed along with the load–displacement curves, and the degrees of crack stability for each parameter were also identified. It was found that there is no difference in the initial failure load between the different marginal thicknesses in all interfacial conditions. The bonded crowns present more resistance to crack propagation. The higher convergence crown preparation can reduce the initial failure load at the crowns’ margin, which can be resisted by a strongly bonded interface. Clear interactions between margin design parameters and their effects on the stress development and crack propagation are necessary to develop an appropriate design of all-ceramic crowns. [Copyright &y& Elsevier]

For the first time, a method of phenol-selective liquefaction is proposed for the fractionation and multilevel conversion of lignocellulose. Through phenol-selective liquefaction, lignin and hemicellulose are liquefied, with large amounts of cellulose retained in the unliquefied residues. Using a phenol/straw ratio of 3 and a sulfuric acid concentration of 3 %, large amounts of hemicellulose (≥85 %) and lignin (≥70 %) can be liquefied at 100 °C in 30 min, with a high quantity of cellulose (≥80 %) retained. Unliquefied residues from selective liquefaction have higher susceptibility for enzymatic attack. Enzymatic hydrolyzation of residues can be as high as 65 % in 48 h with 40.7 FPU/g of dry materials, which can then be used to prepare sugar platform intermediates. The liquefied products of wheat straw are then resinified with formaldehyde in the presence of NaOH as a catalyst and synthesized into phenol formaldehyde-type resins reaching up to GB/T 14732-2006 standards. Phenol selective liquefaction, a new technology for the fractionation of lignocellulose, achieves effective fractionation and multilevel conversion of straw components. Hence, it is an important tool to achieve full utilization of biomass and high value-added conversion of lignocellulose. [ABSTRACT FROM AUTHOR]

This study examined the effect of air abrasion and thermocycling on the adaptation and shear bond strength, of composite resin bonded to dentin using etch-and-rinse and self-etch resin adhesives. Confocal microscopy showed both adhesives closely adapted to dentin and a significantly (p<0.001) greater number of resin tags were observed for the etch-and-rinse adhesive. Air abrasion significantly increased resin tag length (p<0.05) for the etch-and-rinse adhesive and significantly increased the number (p<0.001), length (p<0.001) and thickness (p<0.01) of tags for the self-etch adhesive. However, air abrasion resulted in defect formation within the hybrid layer and thermocycling caused separation of the hybrid layer from adjacent dentin containing resin tags. A significant (p<0.05) reduction in shear bond strength was observed for the etch-and-rinse adhesive following thermocycling. Both adhesive systems adapted well to dentin in vitro and shear bond strengths were similar. The area of tag penetration into dentin was significantly (p<0.0001) enhanced following air abrasion. [ABSTRACT FROM AUTHOR]

Summary: Resin–dentin bonding was first achieved through mechanical hybridization between resin and collagen fibrils using a functional monomer containing resin system. In the last decade, new adhesive resin systems were frequently released onto the market within a short-period of time. Before and after commercialization, the bond integrity has been tested by bond tests, and leakage evaluation by researchers, but it is very difficult for clinicians to obtain a comprehensive, up-to-date understanding of their nature and degradation. Although newly developed adhesive resins have attempted to improve the bond strength at least in the first 24h after bonding, the long-term durability of the bonds has not yet been established analytically. However, numerous recent studies have shown micromorphological evidence of biodegradation of resin–dentin bonds, due to hydrolysis of the resin and collagen fibrils within the bonds. This review mainly summarizes the most recent work in biodegradation of resin–dentin bonds based on micromorphological analyses of data obtained by scanning and transmission electron microscopy. [ABSTRACT FROM AUTHOR]

review is given of scientific research conducted by the All-Russia Institute of the Aircraft Materials for the period of 1940 devoted to the creation of new synthetic adhesives for the aircraft and the optimization of gluing technology using VIAM-B3 adhesive produced previously. The creation of KR4 adhesive with a minimal content of toxic substances in a free state and its use in the development of technology for gluing wooden workpieces, as well as for obtaining flexible VIAM-B3 adhesive, is described for the considered time period. [ABSTRACT FROM AUTHOR]

The main preconditions for developing principally new (for the examined period of time) adhesives based on artificial resins are presented. The results of application of the combined (casein and resin) adhesives, adhesives based on novolak, karbolit and barite phenol formaldehyde resins are given. It is shown that the phenol-barite resin of VIAM-6 grade was the most suitable for the aviation industry at that time. [ABSTRACT FROM AUTHOR]

Abstract: Objective: In a previous study on of polymerization contraction stress determinations of adhesives bonded to dentin a continuous decline of stress was observed after the adhesives had been light-cured. The decline was ascribed to stress relief caused by diffusion into the adhesive layer of water and/or solvents, left in the impregnated dentin surface after drying and/or evaporation in the application procedure. The purpose of the present study was to test the hypothesis that the contraction stress of adhesives bonded to enamel will not decline after light-curing, based on the assumption that water and/or solvents are more efficiently removed from impregnated enamel surfaces in the drying and/or evaporation step. Materials and methods: Contraction stress was determined in a tensilometer for three total-etching adhesives Scotchbond multi-purpose, Single bond and One-step plus and four self-etching adhesives Clearfil SE Bond, Clearfil Protect Bond, AdheSE, and Xeno III. The adhesives were placed in a thin layer between a glass plate and a flat dentin or enamel surface pre-treated with phosphoric acid or self-etching primer and light-cured under constrained conditions. Results: All adhesives bonded to enamel showed a stress decline, but significantly less than for dentin with the exception of two self-etching adhesives. The greatest decline was found for the total-etching adhesive systems bonded to dentin. The presence of hydrophobic monomers in the adhesives had a significant influence on the decline. Significance: The experiments indicate that fluids are withdrawn from the resin impregnated tooth structures, which may result in small defects in the tooth–resin interfaces. [Copyright &y& Elsevier]

The synthesis of a novel melamine-glucose adhesive that is similar to urea-formaldehyde adhesive is reported in this paper. The conditions of synthesis, such as the initial pH, the quantity of catalyst, the temperature of reaction, the percentage of each reactant and the time of reaction, were optimized by using the orthogonal experimental method. [ABSTRACT FROM AUTHOR]

Anisotropically conductive film (ACF) is a smart electronic packaging material that consumes minimal space for connecting integrated circuit (IC) chips to a liquid crystal display (LCD) panel or printed circuit board. It consists of an adhesive resin and fine conductive fillers such as metallic particles or metal-coated polymer balls. The fillers are compressed and maintain a certain elastic capability while conducted between electrodes. The size of the contact area and the shape of the fillers are important factors in determining conductivity. The process of applying ACF is modeled into three consecutive steps, and the stress and deformation states are studied by finite element analysis in each. In step 1 of the manufacturing process, external load is applied to compress the conductive particles at a temperature of 190°C so that the matrix resin is in a fluid condition. In step 2, an external load is maintained at this temperature to allow the matrix resin to solidify; then, the load is released and the particles spring back to create tensile stresses in the bonding resin matrix. The last step considers the bonded and conducting ACF cooling from 190°C to room temperature. The state of stress and deformation will be readjusted due to different contraction properties between the filler and matrix resin. The results presented in this paper show that changing the thickness of a coated nickel layer does not clearly affect the conductivity of ACF, and the deformation should be greater than 40% for the stability of conductivity. [ABSTRACT FROM AUTHOR]

The study aimed to compare the survival time and cariostatic potential of a compomer to that of a resin adhesive when used to bond stainless steel orthodontic brackets to labial segment teeth only. The effect of the patients' sex, age at the start of treatment and presenting malocclusion on bracket survival time was assessed also. Forty-five consecutive patients who attended for fixed appliance therapy were randomly selected. Four hundred twenty-six brackets were bonded (213 with compomer and 213 with resin adhesive) with a split mouth design; the right or left side allocation of compomer in either arch was alternated. Color transparencies of the maxillary incisors, mandibular incisors, or both, and transparencies of the canines, were taken before treatment. At the debond stage, the transparencies were projected (20x) and assessed by an experienced examiner, who used a caries index. The survival time distributions for brackets bonded with each bonding agent were not significantly different (P = .74, paired Prentice-Wilcoxon test; P = .75, Akritas test), with bracket failure rates of 17% and 20% recorded for compomer and resin adhesive, respectively. Neither the patients' sex (P = .85) nor malocclusion (P = .26) appear to affect significantly bracket survival, but patient age was identified as a useful prognostic indicator of bracket survival (P < .001). On average, there was more decalcification related to brackets bonded with resin adhesive than with compomer (P = .0075). Survival time distributions of brackets bonded with compomer or resin adhesive appear comparable, but decalcification was reduced significantly by bonding with compomer. [ABSTRACT FROM AUTHOR]

Forty randomly selected patients had brackets bonded on one side of the of the maxillary labial segment with glass ionomer cement. Teeth on the opposite side were bonded with a resin adhesive. Teeth were assessed for decalcification pretreatment, at debond, and at review using a standardized photographic technique and a modified DDE index. The mean number of teeth affected by decalcification and the mean extent of decalcification per tooth increased during the treatment period, but from debond to review both of these measurements decreased for teeth bonded with either material (p<0.01, t-test). Decalcification appears to become less severe posttreatment, but does not appear to be significantly affected during 12 to 18 months of orthodontic treatment by bonding with glass ionomer cement. Dietary and other environmental factors, including fluoride preparations, may be of greater importance in the prevention of decalcification during fixed appliance therapy. [ABSTRACT FROM AUTHOR]