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1.
Objective
The dental caries is developed as a result of an alternative course of mineral gain and loss. In order to distinguish between intrinsic Ca (tooth-derived mineral) and extrinsic Ca (solution-derived mineral) uptakes, a 44Ca doped pH-cycling was performed using 44Ca (a stable calcium isotope) remineralization solution.Methods
The natural abundance of 40Ca and 44Ca is 96.9% and 2.1%, respectively. The remineralization solution was prepared using 44Ca to contain 1.5 mmol/L CaCl2 (44Ca), 0.9 mmol/L KH2PO4, 130 mmol/L KCl, 20 mmol/L HEPES at pH 7.0. The pH-cycling was conducted on bovine root dentin daily by demineralization (pH 5.0) for 2 h, incubation in 0% (control) and 0.2% NaF (900 ppm fluoride) for 2 h and 44Ca doped remineralization for 20 h. After 14 days pH-cycling, the specimens were sectioned longitudinally. On the sectioned surface, isotope imaging of 40Ca and 44Ca labeled mineral distribution was observed by a high mass-resolution stigmatic secondary ion 77 (Camera IMS 1270, Gennevilliers Cedex, France).Results
Uptake of 44Ca was greater in intensity for the 0.2% fluoride group than the control, especially in the superficial lesions. The control group showed 40Ca (intrinsic) distribution in the subsurface lesions and in the superficial lesions, meanwhile the fluoride group showed 40Ca distribution limited in subsurface lesions. The total Ca (44Ca + 40Ca) image revealed more homogeneously for the control than the fluoride group.Significance
Since the fluoride-treated surface is more acid-resistant than intrinsic dentin, alternative minerals were dissolved from the intact intrinsic lesion in the demineralization cycle. 相似文献2.
Mareike Warkentin Cora Freyse Olaf Specht Detlef Behrend Reinhard Maletz Ralf Janda Peter Ottl 《Dental materials》2018,34(7):1036-1040
Objective
To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample’s top (amplitude).Methods
Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (rS) was calculated (p < 0.05).Results
c(l) was predominantly 6100–7000 ms?1 in enamel and 3800–4600 ms?1 in dentin and correlated significantly with MHV with 27–420 in enamel and 20–90 in dentin (rs = 0,57). Amplitudes significantly correlated with MHV, too, but even better (rs = 0,77).Significance
Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues. 相似文献3.
Kunneng Liang Shimeng Xiao Junling Wu Jiyao Li Michael D. Weir Lei Cheng Mark A. Reynolds Xuedong Zhou Hockin H.K. Xu 《Dental materials》2018,34(4):607-618
Objective
Previous studies investigated short-term dentin remineralization; studies on long-term dentin remineralization after fluid challenges mimicking fluids in oral environment are lacking. The objective of this study was to develop a long-term remineralization method to via poly(amido amine) (PAMAM) and rechargeable composite containing nanoparticles of amorphous calcium phosphate (NACP) after fluid challenges for the first time.Methods
NACP composite was immersed at pH 4 to exhaust its calcium (Ca) and phosphate (P) ions, and then recharged with Ca and P ions, to test the remineralization of the exhausted and recharged NACP composite. Dentin was acid-etched with 37% phosphoric acid. Four groups were prepared: (1) dentin control, (2) dentin with PAMAM, (3) dentin with the recharged NACP composite, and (4) dentin with PAMAM plus recharged NACP composite. PAMAM-coated dentin was immersed in phosphate-buffered saline with shaking for 72 days, because there is fluid flow in the mouth which could potentially detach the PAMAM from dentin. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 35 days.Results
After 72 days of immersion plus shaking, the PAMAM still successfully fulfilled its mineralization nucleation. The recharged NACP composite still provided acid-neutralization and ion re-release, which did not decrease with increasing the number of recharge cycles. The immersed-PAMAM plus NACP achieved complete dentin remineralization and restored the hardness to that of healthy dentin.Signifiance
In conclusion, superior long-term remineralization of the PAMAM plus NACP method was demonstrated for the first time. The immersed-PAMAM plus recharged NACP completely remineralized the pre-demineralized dentin, even after prolonged fluid-challenge similar to that in oral environment. The novel PAMAM plus NACP composite method is promising to provide long-term tooth protection and caries inhibition. 相似文献4.
Yuncong Li Xiaoyi Hu Yang Xia Yadong Ji Jianping Ruan Michael D. Weir Xiaoying Lin Zhihong Nie Ning Gu Radi Masri Xiaofeng Chang Hockin H.K. Xu 《Dental materials》2018,34(9):1310-1322
Objectives
A nanoparticle-doped adhesive that can be controlled with magnetic forces was recently developed to deliver drugs to the pulp and improve adhesive penetration into dentin. However, it did not have bactericidal and remineralization abilities. The objectives of this study were to: (1) develop a magnetic nanoparticle-containing adhesive with dimethylaminohexadecyl methacrylate (DMAHDM), amorphous calcium phosphate nanoparticles (NACP) and magnetic nanoparticles (MNP); and (2) investigate the effects on dentin bond strength, calcium (Ca) and phosphate (P) ion release and anti-biofilm properties.Methods
MNP, DMAHDM and NACP were mixed into Scotchbond SBMP at 2%, 5% and 20% by mass, respectively. Two types of magnetic nanoparticles were used: acrylate-functionalized iron nanoparticles (AINPs); and iron oxide nanoparticles (IONPs). Each type was added into the resin at 1% by mass. Dentin bonding was performed with a magnetic force application for 3 min, provided by a commercial cube-shaped magnet. Dentin shear bond strengths were measured. Streptococcus mutans biofilms were grown on resins, and metabolic activity, lactic acid and colony-forming units (CFU) were determined. Ca and P ion concentrations in, and pH of biofilm culture medium were measured.Results
Magnetic nanoparticle-containing adhesive using magnetic force increased the dentin shear bond strength by 59% over SBMP Control (p < 0.05). Adding DMAHDM and NACP did not adversely affect the dentin bond strength (p > 0.05). The adhesive with MNP + DMAHDM + NACP reduced the S. mutans biofilm CFU by 4 logs. For the adhesive with NACP, the biofilm medium became a Ca and P ion reservoir. The biofilm culture medium of the magnetic nanoparticle-containing adhesive with NACP had a safe pH of 6.9, while the biofilm medium of commercial adhesive had a cariogenic pH of 4.5.Significance
Magnetic nanoparticle-containing adhesive with DMAHDM and NACP under a magnetic force yielded much greater dentin bond strength than commercial control. The novel adhesive reduced biofilm CFU by 4 logs and increased the biofilm pH from a cariogenic pH 4.5–6.9, and therefore is promising to enhance the resin–tooth bond, strengthen tooth structures, and suppress secondary caries at the restoration margins. 相似文献5.
Thiago Henrique Scarabello Stape Leo Tjäderhane Gabriel Abuna Mário Alexandre Coelho Sinhoreti Luís Roberto Marcondes Martins Arzu Tezvergil-Mutluay 《Dental materials》2018,34(7):967-977
Objective
To determine whether bonding effectiveness and hybrid layer integrity on acid-etched dehydrated dentin would be comparable to the conventional wet-bonding technique through new dentin biomodification approaches using dimethyl sulfoxide (DMSO).Methods
Etched dentin surfaces from extracted sound molars were randomly bonded in wet or dry conditions (30 s air drying) with DMSO/ethanol or DMSO/H2O as pretreatments using a simplified (Scotchbond Universal Adhesive, 3M ESPE: SU) and a multi-step (Adper Scotchbond Multi-Purpose, 3M ESPE: SBMP) etch-and-rinse adhesives. Untreated dentin surfaces served as control. Bonded teeth (n = 8) were stored in distilled water for 24 h and sectioned into resin–dentin beams (0.8 mm2) for microtensile bond strength test and quantitative interfacial nanoleakage analysis (n = 8) under SEM. Additional teeth (n = 2) were prepared for micropermeability assessment by CFLSM under simulated pulpar pressure (20 cm H2O) using 5 mM fluorescein as a tracer. Microtensile data was analyzed by 3-way ANOVA followed by Tukey Test and nanoleakage by Kruskal–Wallis and Dunn-Bonferroni multiple comparison test (α = 0.05).Results
While dry-bonding of SBMP produced significantly lower bond strengths than wet-bonding (p < 0.05), DMSO/H2O and DMSO/ethanol produced significantly higher bond strengths for SBMP irrespective of dentin condition (p < 0.05). SU presented significantly higher nanoleakage levels (p < 0.05) and micropermeability than SBMP. Improvement in hybrid layer integrity occurred for SBMP and SU for both pretreatments, albeit most pronouncedly for DMSO/ethanol regardless of dentin moisture.Conclusion
DMSO pretreatments may be used as a new suitable strategy to improve bonding of water-based adhesives to demineralized air-dried dentin beyond conventional wet-bonding. Less porous resin–dentin interfaces with higher bond strengths on air-dried etched dentin were achieved; nonetheless, overall efficiency varied according to DMSO’s co-solvent and adhesive type.Clinical significance
DMSO pretreatments permit etched dentin to be air-dried before hybridization facilitating residual water removal and thus improving bonding effectiveness. This challenges the current paradigm of wet-bonding requirement for the etch-and-rinse approach creating new possibilities to enhance the clinical longevity of resin–dentin interfaces. 相似文献6.
Ornnicha Thanatvarakorn Taweesak Prasansuttiporn Suppason Thittaweerat Richard M. Foxton Shizuko Ichinose Junji Tagami Keiichi Hosaka Masatoshi Nakajima 《Dental materials》2018,34(3):434-441
Objectives
Smear layer deproteinizing was proved to reduce the organic phase of smear layer covered on dentin surface. It was shown to eliminate hybridized smear layer and nanoleakage expression in resin–dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives.Methods
Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond? Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human dentin surfaces with standardized smear layer were prepared. Smear layer deproteinizing was carried out by the application of 50 ppm hypochlorous acid (HOCl) on dentin surface for 15 s followed by Accel® (p-toluenesulfinic acid salt) for 5 s prior to adhesive application. No surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey’s post-hoc test and t-test at the significant level of 0.05.Results
Smear layer deproteinizing significantly improved μTBS of SE, SU, and BB (p < 0.001). Hybridized smear layer observed in control groups of SE, BB, and BF, and reticular nanoleakage presented throughout the hybridized complex in control groups of BB and BF were eliminated upon the smear layer deproteinizing.Significance
Smear layer deproteinizing by HOCl and Accel® application could enhance the quality of dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin–dentin bonding interface. 相似文献7.
The autotransplantation of teeth after cryopreservation has become an increasingly viable method for whole tooth replacement. While the immediate success rates are quite high, damage introduced by cryopreservation within the dentin or enamel could be detrimental to the durability of these teeth.
Objective
to determine whether cryopreservation alters the microstructure of dentin or causes a reduction of its resistance to mechanical failures.Methods
Third molars were obtained from young donors (18≤ age ≤30 yrs) and subjected to a cryopreservation protocol involving storage for 10 days in cryoprotectant solution at ?196 °C. After treatment, the mid-coronal dentin was characterized in terms of its elastic modulus, strength and fatigue behavior. Scanning electron microscopy and Raman spectroscopy were used to evaluate the microstructure and integrity of collagen after cryopreservation.Results
There was no significant difference in the elastic modulus or flexural strength between dentin from the cryopreserved and non-cryopreserved (control) teeth. However, the cryopreservation treatment caused a significant decrease in the fatigue strength of dentin with respect to the controls, with average reduction of nearly 20%. While there were no differences apparent in the collagen matrix or fracture surfaces between the cryopreserved and control groups, the microstructure of dentin from the cryopreserved teeth exhibited unique features and damage that appear to have caused the decrease in durability.Significance
Autotransplantation of cryopreserved teeth may be a viable option for whole tooth restorations, but hidden damage within the dentin could render these teeth more susceptible to mechanical failures by fatigue and fracture. 相似文献8.
Objective
To provide insight of the setting reactions of Biodentine?, a hydraulic calcium silicate cement, based upon observations using Fourier Transform Infra-Red (FTIR) spectroscopy.Methods
FTIR spectra of components before and during the setting reaction were taken using the attenuated total reflectance (ATR) technique. Measurements over wavelengths 600–4000 cm?1 were taken at regular intervals for two days.Results
FTIR spectrum of Biodentine? powder revealed a number of peaks from 650 to 1100 cm?1 and a plateau from 1400 to 1500 cm?1, indicative of SiO and CO3-bonding, while the mixing fluid exhibited water peaks. Results following mixing displayed three distinct regimes; (i) incubation phase, during the first 35 min, when minimal change occurred, (ii) rapid transitory stage, between 35 and 90 min, when major changes occurred, and (iii) slow sustained reaction stage for remaining 45 h. Incubation appears to be associated with the presence of CO3-peaks. The transition region indicates formation of CaOH and Jennite OH-peaks, anticipated intermediate reaction phases. At 90 min, the end of second stage, CaOH and Jennite are replaced by a dominant Portlandite (Ca(OH)2)-peak and minor presence of Tobermorite, another anticipated intermediate phase, and water reduction. During the following 45 h Portlandite and Tobermorite decline while the water peak increases.Significance
FTIR can be used to follow the chemical reactions in dental cements and provides insight into the relatively slow setting reactions of hydraulic calcium silicate cements. 相似文献9.
Xin Li Mariano Simón Pedano Bernardo Camargo Esther Hauben Stéphanie De Vleeschauwer Zhi Chen Jan De Munck Katleen Vandamme Kirsten Van Landuyt Bart Van Meerbeek 《Dental materials》2018,34(9):1410-1423
Objectives
To overcome shortcomings of hydraulic calcium-silicate cements (hCSCs), an experimental tricalcium silicate (TCS) cement, named ‘TCS 50’, was developed. In vitro research showed that TCS 50 played no negative effect on the viability and proliferation of human dental pulp cells, and it induced cell odontogenic differentiation. The objective was to evaluate the pulpal repair potential of TCS 50 applied onto exposed minipig pulps.Methods
Twenty permanent teeth from three minipigs were mechanically exposed and capped using TCS 50; half of the teeth were scheduled for 7-day and the other half for 70-day examination (n = 10). Commercial hCSCs ProRoot MTA and TheraCal LC were tested as references (n = 8). Tooth discoloration was examined visually. After animal sacrifice, the teeth were scanned using micro-computed tomography; inflammatory response at day 7 and day 70, mineralized tissue formation at day 70 were assessed histologically.Results
Up to 70 days, TCS 50 induced no discoloration, ProRoot MTA generated gray/black discoloration in all teeth. For TCS 50, 40.0% pulps exhibited a mild/moderate inflammation at day 7. No inflammation was detected and complete reparative dentin with tubular structures was formed in all pulps after 70 days. ProRoot MTA induced a similar response, TheraCal LC generated a less favorable response in terms of initial inflammation and reparative dentin formation; however, these differences were not significant (Chi-square test of independence: p > 0.05).Significance
TCS 50 induced reparative dentinogenesis in minipig pulps. It can be considered as a promising pulp-capping agent, also for aesthetic areas. 相似文献10.
Ya-ping Gou Ji-yao Li Mohamed M. Meghil Christopher W. Cutler Hockin H.K. Xu Franklin R. Tay Li-na Niu 《Dental materials》2018,34(12):1814-1827
Objective
Secondary caries and degradation of hybrid layers are two major challenges in achieving durable resin–dentin bonds. The objectives of the present study were to investigate the effects of a 2% quaternary ammonium silane (QAS) cavity cleanser on bacteria impregnated into dentin blocks and the gelatinolytic activity of the hybrid layers.Methods
Microtensile bond strength was first performed to evaluate if the 2% QAS cavity cleanser adversely affected bond strength. For antibacterial testing, Streptococcus mutans and Actinomyces naeslundii were impregnated into dentin blocks, respectively, prior to the application of the cavity cleanser. Live/dead bacterial staining and colony-forming unit (CFU) counts were performed to evaluate their antibacterial effects. Gelatinolytic activity within the hybrid layers was directly examined using in-situ zymography. A double-fluorescence technique was used to examine interfacial permeability immediately after bonding.Results
The cavity cleanser did not adversely affect the bond strength of the adhesives tested (p > 0.05). Antibacterial testing indicated that 2% QAS significantly killed impregnated bacteria within the dentin blocks compared with control group (p < 0.05), which was comparable with the antibacterial activity of 2% chlorhexidine (p > 0.05). Hybrid layers pretreated with 2% QAS showed significant decrease in enzyme activity compared with control group. With the use of 2% QAS, relatively lower interfacial permeability was observed, compared with control group and 2% chlorhexidine (p < 0.05).Significance
The present study developed a 2% QAS cavity cleanser that possesses combined antimicrobial and anti-proteolytic activities to extend the longevity of resin–dentin bonds. 相似文献11.
Pong Pongprueksa Jan De Munck Masanao Inokoshi Bart Van Meerbeek 《Dental materials》2018,34(4):684-692
Objective
To evaluate the effect of the kind and concentration of photo-initiator on the degree of conversion (DC) of adhesives on dentin/glass substrates and their mini-interfacial fracture toughness (mini-iFT) to dentin.Methods
We tested the adhesive Clearfil S3 Bond Plus and 4 derived experimental ‘LUB’ (‘Leuven Univesity Bond’) adhesives (all from Kuraray Noritake), namely ‘LUB-CQ/amine_high’, ‘LUB-CQ/amine_low’, ‘LUB-TPO_high’, and ‘LUB-TPO_low’, respectively containing 2.0 wt% camphorquinone (CQ) and 2.0 wt% EDMAB (amine), 0.35 wt% CQ and 0.35 wt% amine, 2.0 wt% TPO, and 0.35 wt% TPO. For DC, each adhesive was applied onto glass or dentin prior to being cured (Bluephase 20i; Ivoclar Vivadent: “high mode”) for 10 s. DC was measured at 5 min, 10 min, 1 h, 24 h and 1 week using micro-Raman spectroscopy (SENTERRA; BrukerOptik). For mini-iFT, each adhesive was bonded to 320-grit SiC-paper ground dentin and covered with composite (Z100; 3 M ESPE). The restored teeth were cut in sticks (1.5 × 2.0 × 16 mm), after which a single-gradient notch was prepared at the adhesive-dentin interface using a 150-μm diamond blade. The micro-specimens were loaded until failure in a 4-point bending test and the mini-iFT in term of KQvM was calculated.Results
DC was higher on dentin than on glass. All adhesives were adequately polymerized at 1 week, except for LUB-TPO_low. DC at 5 min was significantly higher for LUB-TPO_high than for both CQ/amine-based adhesives. The highest and most reliable mini-iFT was measured for LUB-CQ/amine_high, despite its 5-min DC was relatively low. No correlation between DC and mini-iFT was found.Significance
Curing of TPO-based adhesives is faster, but the dark cure of the CQ/amine-containing adhesives is more efficient. The differences in curing profiles do affect the mechanical properties of the resultant interfaces at dentin. 相似文献12.
Jaiane Bandoli Monteiro Hilton Riquieri Catina Prochnow Luís Felipe Guilardi Gabriel Kalil Rocha Pereira Alexandre Luiz Souto Borges Renata Marques de Melo Luiz Felipe Valandro 《Dental materials》2018,34(6):891-900
Objectives
To evaluate the effect of ceramic thickness on the fatigue failure load of two zirconia-reinforced lithium silicate (ZLS) glass-ceramics, adhesively cemented to a dentin analogue material.Methods
Disc-shaped specimens were allocated into 8 groups (n = 25) considering two study factors: ZLS ceramic type (Vita Suprinity — VS; and Celtra Duo — CD), and ceramic thickness (1.0; 1.5; 2.0; and 2.5 mm). A trilayer assembly (? = 10 mm; thickness = 3.5 mm) was designed to mimic a bonded monolithic restoration. The ceramic discs were etched, silanized and luted (Variolink N) into a dentin analogue material. Fatigue failure load was determined using the Staircase method (100,000 cycles at 20 Hz; initial fatigue load ～60% of the mean monotonic load-to-failure; step size ～5% of the initial fatigue load). A stainless-steel piston (? = 40 mm) applied the load into the center of the specimens submerged in water. Fractographic analysis and Finite Element Analysis (FEA) were also performed.Results
The ceramic thickness influenced the fatigue failure load for both ZLS materials: Suprinity (716 N up to 1119 N); Celtra (404 N up to 1126 N). FEA showed that decreasing ceramic thickness led to higher stress concentration on the cementing interface.Significance
Different ZLS glass-ceramic thicknesses influenced the fatigue failure load of the bonded system (i.e. the thicker the glass ceramic is, the higher the fatigue failure load will be). Different microstructures of the ZLS glass-ceramics might affect the fatigue behavior. FEA showed that the thicker the glass ceramic is, the lower the stress concentration at the tensile surface will be. 相似文献13.
Salvatore Sauro Ashvin Babbar Borzo Gharibi Victor Pinheiro Feitosa Ricardo Marins Carvalho Lidiany Karla Azevedo Rodrigues Avijit Banerjee Timothy Watson 《Dental materials》2018,34(6):868-878
Objective
Materials for pulp protection should have therapeutic properties in order to stimulate remineralization and pulp reparative processes. The aim of this study was to evaluate the mechanical properties, biocompatibility, cell differentiation and bioactivity of experimental light-curable resin-based materials containing bioactive micro-fillers.Methods
Four calcium-phosphosilicate micro-fillers were prepared and incorporated into a resin blend: 1) Bioglass 45S5 (BAG); 2) zinc-doped bioglass (BAG-Zn); 3) βTCP-modified calcium silicate (β-CS); 4) zinc-doped β-CS (β-CS-Zn). These experimental resins were tested for flexural strength (FS) and fracture toughness (FT) after 24 h and 30-day storage in simulated body fluid (SBF). Cytotoxicity was evaluated using MTT assay, while bioactivity was evaluated using mineralization and gene expression assays (Runx-2 & ALP).Results
The lowest FS and FT at 24 h was attained with β-CS resin, while all the other tested materials exhibited a decrease in FS after prolonged storage in SBF. β-CS-Zn maintained a stable FT after 30-day SBF aging. Incorporation of bioactive micro-fillers had no negative effect on the biocompatibility of the experimental materials tested in this study. The inclusion of zinc-doped fillers significantly increased the cellular remineralization potential and expression of the osteogenic genes Runx2 and ALP (p < 0.05).Significance
The innovative materials tested in this study, in particular those containing β-CS-Zn and BAG-Zn may promote cell differentiation and mineralization. Thus, these materials might represent suitable therapeutic pulp protection materials for minimally invasive and atraumatic restorative treatments. 相似文献14.
Annalisa Mazzoni Valeria Angeloni Allegra Comba Tatjana Maravic Milena Cadenaro Arzu Tezvergil-Mutluay David H. Pashley Franklin R. Tay Lorenzo Breschi 《Dental materials》2018,34(2):288-295
Objective
The objectives of the study were to evaluate the ability of a 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDC)-containing primer to improve immediate bond strength of either self-etch or etch-and-rinse adhesive systems and to stabilize the adhesive interfaces over time. A further objective was to investigate the effect of EDC on the dentinal MMPs activity using zymographic analysis.Methods
Freshly extracted molars (n = 80, 20 for each group) were selected to conduct microtensile bond strength tests. The following groups were tested, immediately or after 1-year aging in artificial saliva: G1: Clearfil SE (CSE) primer applied on unetched dentin, pretreated with 0.3 M EDC water-solution for 1 min and bonded with CSE Bond; G2: as G1 but without EDC pre-treatment; G3: acid-etched (35% phosphoric-acid for 15s) dentin pretreated with 0.3 M EDC, then bonded with XP Bond (XPB); Group 4 (G4): as G3 without EDC pre-treatment. Further, gelatinase activity in dentin powder treated with CSE and XPB with and without EDC pre-treatment, was analyzed using gelatin zymography.Results
The use of 0.3 M EDC-containing conditioner did not affect the immediate bond strength of XPB or CSE adhesive systems (p > 0.05), while it improved the bond strength after 1 year of aging (p < 0.05). Pre-treatment with EDC followed by the application of CSE resulted in an incomplete MMPs inactivation, while EDC pretreatment followed by the application of XPB resulted in an almost complete inactivation of dentinal gelatinases.Significance
The μTBS and zymography results support the efficacy of EDC over time and reveal that changes within the dentin matrix promoted by EDC are not adhesive-system-dependent. 相似文献15.
Anuradha Prakki Yaoyang Xiong Janaína Bortolatto Lucélia Lemes Gonçalves Arwa Bafail Greg Anderson Alexander Terry Stavroullakis 《Dental materials》2018,34(11):1625-1633
Objectives
We investigated the biostability of dentin organic matrices treated with epigallocatechin gallate (EGCG) in comparison to chlorhexidine (CHX), both extracted from functionalized copolymers.Methods
Copolymers were prepared with bis-GMA:TEGDMA and incorporated with 1% of EGCG or CHX (w/w). Blank copolymers were used as control. Copolymer samples were individually stored in 1 mL deionized water to produce copolymer extracts. Dentin matrices were obtained by demineralization of dentin disks in 10% phosphoric acid solution. Matrices were individually treated with 1 mL of the copolymer extracts or distilled water for 48 h. Collected extracts were analyzed by high-performance liquid chromatography (HPLC) for the presence and quantification of EGCG, CHX, and copolymer by-products. Treated dentin matrices were tested for ultimate tensile strength, gravimetric changes, and swelling ratio. The treatment media were tested for total protein concentration, and dentin protease activity through solubilized telopeptide (ICTP- and CTX-ELISA) assays. The treatment media were also submitted to proteomic analysis.Results
HPLC identified released unreacted copolymer species and showed higher release of CHX compared to EGCG from respective copolymer extracts. EGCG extract inhibited activity of dentin proteolytic enzymes and promoted collagen biomodification observed by the telopeptide assays and in the changes to dentin matrix properties. The proteomic results showed less collagenous peptide hits in the EGCG extract media compared to CHX, and suggest compound-specific dentin protein binding interactions.Significance
This study demonstrates specific antiproteolytic effect and protein interactions of EGCG copolymer extract directly on dentin. This represents an advancement in dental materials which can impact the clinical procedures. 相似文献16.
Taichi Iwashita Atsushi Mine Mariko Matsumoto Hayaki Nakatani Mami Higashi Asuka Kawaguchi-Uemura Tomoshige Kabetani Yuko Tajiri Dai Imai Ryosuke Hagino Jiro Miura Takuya Minamino Hirofumi Yatani 《Journal of prosthodontic research》2018,62(4):449-455
Purpose
The purpose of this study was to evaluate drying methods for post space dentin bonding in a direct resin composite core build-up method.Methods
Experiment 1: Four root canal plastic models, having diameters of 1.0 or 1.8 mm and parallel or tapered shapes, were prepared. After drying each post space using three drying methods (air drying, paper-point drying, or ethanol drying, which involves filling the space with 99.5 vol% ethanol followed by air drying), the residual liquid in the models was weighed. Experiment 2: Thirty endodontically treated single-root teeth were dried using the above-described drying methods and filled with dual-cure resin composite. The bonded specimens were sectioned into square beams of approximately 1 mm2 for microtensile bond strength (μTBS) testing. Nine teeth were observed through transmission electron microscopy (TEM) and micro computed tomography (μCT). The weight of residual liquid and μTBS were analyzed using Scheffé multiple comparison.Results
Experiment 1: The results of air drying were significantly different from those of paper-point drying (p < 0.001) and ethanol drying (p < 0.001), and no significant difference was observed between paper-point drying and ethanol drying. Experiment 2: The μTBS significantly decreased in the order of ethanol drying, paper-point drying, and air drying (air drying/ethanol drying: p < 0.001, air drying/paper-point drying: p = 0.048, ethanol drying/paper-point drying: p = 0.032). TEM and μCT observation revealed a sufficient dentin/adhesive interface in the ethanol drying group.Conclusions
Ethanol drying was found to be more effective for post space dentin bonding, as compared with air drying and paper-point drying. 相似文献17.
Kunneng Liang Shimeng Xiao Hongling Liu Wenyuan Shi Jianshu Li Yuan Gao Libang He Xuedong Zhou Jiyao Li 《Dental materials》2018,34(4):629-640
Objective
Eight repetitive nucleotide sequences of aspartate–serine–serine (8DSS) derived from dentin phosphoprotein (DPP) has been proved to be a good remineralization agency. In this study, 8DSS peptide was employed to induce dentinal tubule occlusion.Methods
Dentin samples were acid-etched, and then the samples were coated with 8DSS solution. The binding capacity of 8DSS to acid-etched dentin was tested by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Subsequently, the 8DSS-treated dentin samples were immersed in artificial saliva for 1, 2 and 4 weeks. After 4 weeks, the remineralized dentin was treated with 6 wt% citric acid (pH 1.5) solution for 1 min. Dentin permeability measurement and scanning electron microscopy (SEM) were carried out after different periods. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to identify the mineral phase of the regenerated minerals.Results
The results showed that 8DSS had a good binding capacity to the acid-etched dentin, and significantly reduced the dentin permeability by inducing minerals deposited within the dentinal tubules. After 4 weeks, all the dentinal tubules were occluded by large bulk of regenerated minerals, which largely decreased the diameters of the tubules. The regenerated minerals deposited with a deep depth within the dentinal tubules, ensuring an effective occlusion even after an acid challenge. The results of XRD and EDS confirmed that the regenerated minerals were mainly hydroxyapatite (HA).Significance
8DSS peptide induced strong dentinal tubule occlusion. 8DSS have a great potential to be used in the treatment of dentin hypersensitivity in the future. 相似文献18.
Jovana Marjanovic Djordje N. Veljovic Jovana N. Stasic Tatjana Savic-Stankovic Branka Trifkovic Vesna Miletic 《Dental materials》2018,34(5):737-745
Objectives
To evaluate optical properties (color and translucency) of ‘sandwich’ restorations of resin-based composites and esthetically unfavorable dentin restoratives.Methods
Cylindrical ‘dentin’ specimens (8 mm in diameter and 2 mm thick, N = 5/group) were prepared using EverX Posterior (GC), Biodentine (Septodont), experimental hydroxyapatite (HAP) or conventional composites (Gradia Direct Posterior, GC; Filtek Z250 and Filtek Z500, 3M ESPE). Capping ‘enamel’ layers were prepared using composites (Gradia Direct Posterior, Filtek Z250 or Z550) of A1 or A3 shade and the following thickness: 0.6, 1 or 2 mm. Color (ΔE) and translucency parameter (TP) were determined using a spectrophotometer (VITA Easyshade Advance 4.0, VITA Zahnfabrik). Data were statistically analyzed using analysis of variance with Tukey’s post-hoc tests (α = 0.05).Results
TP was greatly affected by layer thickness, whilst ΔE depended on shade and layer thickness of the capping composite. HAP and Biodentine showed significantly lower TP and higher ΔE (deviation from ‘ideal white’) than composites (p < 0.05). Greater TP was seen in EverX_composite groups than in corresponding control groups of the same shade and thickness. TP of composites combined with Biodentine or HAP was below 2, lower than the corresponding control groups (p < 0.05). Within-group differences of ΔE were greatest in HAP_composite groups. EverX_Gradia and EverX_FiltekZ250 combinations showed the most comparable ΔE with the control groups.Significance
A 2 mm thick layer of composite covering dentin restoratives with unfavorable esthetics is recommended for a final ‘sandwich’ restoration that is esthetically comparable to a conventional, mono-composite control restoration. 相似文献19.
Takehiro Yaguchi 《Dental materials》2017,33(1):23-32
Objective
The 10-methacryloyloxydecyl dihydrogen phosphate (MDP) (EX adhesives)-based one-step self-etch adhesives have become widely utilized due to their simplified application procedures. The aim of this study was to determine the type of the molecular species of calcium salts of MDP (MDP-Ca salts) that form a layered structure and to understand the layering mechanism of MDP-Ca salts.Methods
The EX adhesives were prepared by varying the amounts of MDP (25.6, 49.9, 80.5 and 116.1 mg) added in 1 g of the EX adhesive. Enamel and dentin reactant residues were obtained after the reaction of each EX adhesive to enamel or dentin particles for 30 s. The chemical analyses of both reactant residues were then performed.Results
The molecular species of MDP-Ca salts that form a layered structure were determined as mono-calcium salt (MCS-MD) and di-calcium salts of the MDP dimer (DCS-MD). The dentin sample showed two types of characteristic XRD peaks assigned to the layer structure, since the dentin produced DCS-MD along with MCS-MD in contrast to the enamel sample. A mono-calcium salt of the MDP monomer (MCS-MM), a predominant molecular species, was not contributed to a layered-structure formation, since the intensities of characteristic XRD peaks are limited by the production of DCS-MD and MCS-MD.Significance
The self-assembled layering of MCS-MD and DCS-MD is associated by a hydrophobic bond between two 10-methylene groups in MCS-MD and DCS-MD. The MCS-MD may form a more tightly-packed layered structure than DCS-MD by the hydrogen bonded interaction between hydroxy groups bonded to each phosphorous atom. 相似文献20.
Keita Taguchi Keiichi Hosaka Masaomi Ikeda Ryuzo Kishikawa Richard Foxton Masatoshi Nakajima Junji Tagami 《Journal of prosthodontic research》2018,62(3):330-336