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Dental resin adhesive is a mixture of monomers used as an adhesive in resin-based composite tooth restoration. Methacrylate monomers used in these adhesives are susceptible to hydrolysis by bacterial enzymes, leading to limitation of their lifespan. To overcome this issue, in this research series of quaternary ammonium-containing methacrylamides, MDAB (m ethacrylamidoethyl d imethyl a mmonium b romide) and MDAF (m ethacrylamidoethyl d imethyl a mmonium f luoride), acrylamides, ADAB (a crylamidoethyl d imethyl a mmonium b romide) and bismethacrylamides, bis-MMAI (bis (2- m ethacrylamidoethyl) m ethyl a mmonium i odide) were synthesized. These new monomers exhibited antibacterial properties against common bacteria found in tooth cavities, which are S. mutans and E. faecalis. Extra methyl moiety on polymerizable group and long alkyl chain length increased antibacterial properties as well as cytotoxicity against MDPC.23 mouse dental papilla cell lines. Acrylamides, ADAB showed the least cytotoxicity with higher MBC values than the commonly used methacrylate monomer, bis-GMA and the only antibacterial methacrylate-based monomer currently used in commercial resin adhesives, MDPB (m ethacryloyl d odecyl p yridinium b romide). Steric hindrance and lipophilicity of bismethacrylamides in bis-MMAI series reduced antibacterial activities and also significantly enhanced cytotoxicity of the monomers. Moreover, bromide and fluoride counter ions in MDAB and MDAF , respectively, did not cause any difference in antibacterial effects. Additionally, all synthesized (meth)acrylamide monomers demonstrated greater stability against hydrolysis under acidic conditions compared to the methacrylate MDPB. Degree of conversions of synthesized monomers were lower than that of MDPB at the beginning of polymerization due to the higher viscosity, but were comparable at the latter stage. Methyl group on methacrylamides in MDAB and the highest viscosity of bismethacrylamides, bis-MMAI reduced degree of conversions of the monomers. TADAB (t etradecyl a crylamidoethyl d imethyl a mmonium b romide) incorporated in resin adhesive reduced water solubility of the cured resin under acidic condition. [Display omitted] • New synthetic routes for quaternary ammonium-containing (meth)acrylamides were proposed. • Some monomers were antibacterial and non-cytotoxic to mouse dental papilla cells. • All monomers showed distinguished hydrolytic stability under acidic aqueous solution. • Degree of conversions of (meth)acrylamides at 30 s were comparable to a reference methacrylate. [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]

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]

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]

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]

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: 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]