Novel self-healing dental luting cements with microcapsules for indirect restorations (original) (raw)
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Dental materials : official publication of the Academy of Dental Materials, 2015
Bulk fracture is one of the primary reasons for resin-based dental restoration failures. To date, there has been no report on the use of polymerizable dental monomers with acceptable biocompatibility to develop a resin with substantial self-healing capability. The objectives of this study were to: (1) develop a self-healing resin containing microcapsules with triethylene glycol dimethacrylate (TEGDMA)-N,N-dihydroxyethyl-p-toluidine (DHEPT) healing liquid in poly(urea-formaldehyde) (PUF) shells for the first time, and (2) determine the physical and mechanical properties, self-healing efficiency, and fibroblast cytotoxicity. Microcapsules of polymerizable TEGDMA-DHEPT in PUF were prepared via an in situ polymerization method. Microcapsules were added into a BisGMA-TEGDMA resin at microcapsule mass fractions of 0%, 5%, 10%, 15% and 20%. A flexural test was used to measure composite strength and elastic modulus. A single edge V-notched beam method was used to measure fracture toughness ...
Effects of Self-healing Microcapsules on Dental Resin Composites
2020
Dental restorations of resin-based composites mainly fail due to secondary caries and bulk fracture. Self-healing strategies in polymeric materials have been shown to enhance the mechanical properties with the ability of self-repair and crack inhibition, suggesting a prolonged life for dental composite restorations. The systematic review on self-healing dental composites (SHDCs) concluded that a healing performance of 25-80 % recovery rate of the virgin fracture toughness can been achieved based on current literature. The selfhealing systems used were PUF microcapsules of DCPD and TEGDMA-DHEPT or silica microcapsules of water/polyacid healing agent. TEGDMA-DHEPT microcapsules were synthesised as they have been proven previously to be biocompatible for dental materials. Microcapsules were prepared by in situ emulsion polymerisation of PUF shells (average diameter 150-300 μm). The experimental SHDC included: Bis-GMA:TEGDMA (1:1), 1 wt% BAPO, 0.5 wt% BPO catalyst, 20 wt% SiO2 (15 nm), and (0, 2.5, 5, 7.5, 10 wt%) of microcapsules. SEM imaging of the capsular shell revealed a smooth outer surface with deposits of PUF nanoparticles which offers a rough surface that may improve resin matrix retention. FT-IR showed that microcapsules crushed with BPO catalyst had DC of up to 60.3 %. The DC of SHDC after 24 h polymerisation was 73-76 % (P>0.05), micro-hardness 22-26 VHN (P>0.05), however, the flexural strength was reduced significantly from 80 to 55 MPa with increasing microcapsules to 10 wt% in composites (P<0.05). Microencapsulation parameters that can affect the microcapsule properties in the material performance were explored. Stirring speed and ratio of core:shell materials influenced: size/polydispersity of microcapsules 130-300 µm; microcapsule fill content 90-98 %; encapsulation efficiency 37-78 %; encapsulation yield 33-59 %; capsule permeability 6-25 % (leaking in 28 days). Composites containing 10 wt% microcapsules showed self-healing performance reached up to 36 % (recovery rate) in dental composite. The model SHDC may have the capability for crack-repair and prevention of catastrophic failure of dental restorations.
The Journal of Prosthetic Dentistry, 2014
Statement of problem. The lack of long-term bond stability between resin cements and dentin may compromise the success of indirect restorations. Purpose. The purpose of this study was to evaluate the effects of long-term storage in artificial saliva and mechanical load cycling on the microtensile bond strength of conventional and self-adhesive resin cements to dentin. Material and methods. The occlusal dentin surfaces of 128 human molars were exposed and flattened. The teeth were assigned to 16 groups (n¼8) according to resin cement and in vitro aging strategy. Two self-adhesive resin cements (RelyX Unicem and Clearfil SA Cement) and 2 conventional cementing systems (RelyX ARC and Clearfil Esthetic Cement) were used. Resin cements were applied to prepolymerized indirect resin disks, which were bonded to the dentin surfaces and light polymerized. The control groups were represented by immediate microtensile bond strength (24 hours) and aging methods were performed with mechanical load cycling or storage in artificial saliva (1 year and 2 years). Bonded beams were tested in tension until failure. Data (MPa) were analyzed by Proc Mixed for repeated measures and the Tukey-Kramer test (a¼.05). Results. The self-adhesive resin cements exhibited higher microtensile bond strength than conventional cementing systems for all conditions studied. The microtensile bond strength of RelyX ARC and self-adhesive resin cements did not decrease after storage in artificial saliva and mechanical load cycling. The Clearfil Esthetic Cement showed the lowest microtensile bond strength and a significant reduction after 2 years of storage in artificial saliva. Conclusions. The storage times and mechanical load cycling did not affect the microtensile bond strength of self-adhesives and RelyX ARC resin cements. The highest microtensile bond strength was obtained for self-adhesive resin cements, with no significant difference between them. (J Prosthet Dent 2014;111:404-410) Clinical Implications Self-adhesive cements seem to be a good alternative for luting indirect restorations to a dentin surface.
We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction). Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mm/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin (P < 0.001). Micro-tensile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions (P < 0.001). Immediate micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements (P < 0.001). It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.
Al-Azhar Dental Journal for Girls, 2018
Purpose: The present study aimed to investigate the effect of incorporation of the new Triethylene glycoldimethacrylate and N,N-Bis(2-hydroxyethyl)-p-toluidine (TEGDMA)-(DHEPT) in polyurea formaldehyde (PUF) micro-capsules into an experimental dental resin composite on the flexural strength and fracture toughness and the evaluation of its self-healing efficacy. Materials and Methods: Polyurea formaldehyde microcapsules were synthesized by insitu polymerization technique, encapsulating a triethylene glycol dimethacrylate and dihydroxy ethyl para toluidine (TEGDMA-DHEPT) as a healing liquid, then experimental composite resin is prepared. Microcapsules are incorporated in the resin composite with concentrations 0%, 2.5%, 5%, 7.5% and 10%, then experimental resin composite specimens were fabricated. Fracture toughness and flexural strength were examined by three point loading using universal testing machine till fracture. The fracture toughness was evaluated by using single edge V-notched beam method, self healing efficacy is evaluated as the ratio between the healed fracture toughness and the virgin fracture toughness. Results: Regarding flexural strength results, it was found that the 0% group has the highest flexural strength while the 10% group had the lowest flexural strength. On the other hand, on evaluating the results, of 7.5% group it was found that this concentration did not affect the flexural strength remarkably. Regarding the virgin fracture toughness results, 0% group has the highest flexural strength, while the 10% group the lowest flexural strength, specimens were fractured and healed, then fractured again to measure the healed fracture toughness, on examining the results of the healed fracture toughness, it was found that no significant difference between 0% and 2.5% as no healing occur at such specimen, Also the results showed that the highest healed fracture toughness was in 5%, followed by 7.5%, followed by 10%. The self-healing efficacy increased to Codex : 66/1810
Materials Research, 2016
The purpose of this study was to evaluate the effects of long-term storage on the microtensile bond strength (µTBS) to dentin of two self-adhesive and three multi-step resin cements. Two self-adhesive cements RelyX U100 (U100) and seT PP (SET), and 3 multi-step resin cements, one using 2-step etch-and-rinse adhesive AllCem (ALC), and two conventional resin cements with self-etching primer Panavia F (PAN) and Multilink (MULT) were used. Human molars were restored (n=5), sectioned and subjected to the μTBS test after 24 h and 6 months. Fractured specimens were examined by stereomicroscope and SEM. The µTBS were analyzed by one-way ANOVA and Tukey test (α=0.05). ANOVA revealed a difference between groups (p<0.0001). All multi-step resin cements ALC, MULT and PAN showed statistically similar bond strength values that were higher than those of the U100 and SET groups. The bond strength value of ALC, MULT and PAN decreases significantly after 6 months. The majority of the failures were adhesive for all the groups. The µTBS produced by the self-adhesive cements were significantly lower than those observed for multi-step luting agents. Regardless of the numbers of steps of resin cements, the storage time reduces µTBS values to dentin only to multi-step luting agents.
Open Access Macedonian Journal of Medical Sciences, 2020
AIM: Investigation of the aging effect on the microtensile bond strength (μTBS) of bulk-fill resin composite (RC) versus a conventionally incrementally applied one. MATERIALS AND METHODS: A total number of 45 sound human impacted third molars extracted molars have been selected to prepare specimens for the μTBS test. Teeth were randomly divided into three groups (C) according to type of RC material which used for restoring the teeth. Where nanohybrid RC (Grandio®SO) was used as the control Group (C1), packable bulk-fill RC (X-tra fil®) was used for restoring teeth in C2 group and flowable bulk-fill RC (X-tra base®) was used for restoring teeth in C3 group. Each group was further subdivided into 3 subgroups (n = 5) according to the water storage time, where in subgroup 1; teeth were stored for 24 h, subgroup 2; teeth were stored for 3 months while for subgroup 3; and teeth were stored for 6 months. After water storage, teeth were sectioned for preparation of μTBS testing beams. Maxim...
Influence of temporary cements on bond strength between resin-based luting agents and dentin
American journal of dentistry, 2006
To examine the influence of temporary cements on the strength of the bond formed between resin-based luting agents and dentin. An acrylic resin plate was luted to bovine dentin using one of three temporary cements; HY-Bond Temporary Cement Hard (HYB), Freegenol Temporary Pack (FTP), or Neodyne T (NDT). The control group (CON) was not treated with cement. Following the removal of the temporary cement, each dentin substrate was bonded to a silane-treated ceramic material (IPS Empress) with one of four luting agents; Super-Bond C&B (SCB), Panavia F (PAF), Nexus II (NEX), or Fuji Luting S (FLS). The specimens were immersed in water for 24 hours and the strength of the bond to shearing forces was determined. The bond strengths (in MPa), with statistical categories shown in parentheses were: HYB (25.7, a), CON (23.5, a, b), FTP (19.8, b, c), and NDT (16.8, c, d) for the SCB system; FTP (13.8, d, e), CON (12.9, d, e), NDT (10.6, e, f), and HYB (7.8, f, g, h) for the PAF system; FTP (9.2, e...