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1.
Arunee Laiteerapong Franz-Xaver Reichl Yang Yang Reinhard Hickel Christof HÖgg 《Dental materials》2018,34(2):282-287
Objectives
(1) To investigate the genotoxicity of a glass ionomer cement (GIC) and GIC incorporated with titanium dioxide nanopoarticle (TiO2NPs) and with microparticle (TiO2MPs) on DNA double-strand breaks of human gingival fibroblast cells (HGFs). (2) To compare the genotoxic differences between GIC and two modified cements.Methods
TiO2NPsGIC and TiO2MPsGIC were prepared by adding 10% w/w of TiO2NPs and TiO2MPs to the GIC powder and hand-mixed followed the manufacturer instruction. Dulbecco’s Minimum Essential Medium (DMEM) was used as a culture medium for HGFs and eluate preparation. Eluates from all groups were collected for XTT cell viability assay to obtain EC50 values. γ-H2AX immunofluorescence assay was performed to detect DNA double-strand breaks (DSBs) of HGFs.Results
EC50 values were from 38% to 60% and eluate concentrations at 20% and 5% were selected for γ-H2AX immunofluorescence assay. At both concentrations, HGFs exposed to eluates from all cements groups had fewer mean foci per cell and higher percentage of free foci cells than H2O2 (p < 0.05). At 20% concentration, cells exposed to eluates from both TiO2NPsGIC and TiO2MPsGIC groups had fewer mean foci per cell and higher percentage of free foci cell than GIC and culture medium (p < 0.05).Significance
Neither GIC nor 10% TiO2-modified GICs had a genotoxic effect on HGFs. Both TiO2NPsGIC and TiO2MPsGIC demonstrated less genotoxic effect than GIC. When comparing between the two modified cements, there was no genotoxic difference between the modified cements from different particle sizes (nanoparticle and micro-particle) of TiO2. 相似文献2.
Arunee Laiteerapong Franz-Xaver Reichl Reinhard Hickel Christof Högg 《Dental materials》2019,35(3):444-449
Objective
To formulate novel glass ionomer cements (GICs) containing zirconia (nanoparticles (NPs) and micro-particles (MPs)) and investigate the genotoxic effect of their eluates on DNA double-strand breaks of human gingival fibroblasts (HGFs) in vitro using a γ-H2AX fluorescent assay.Methods
GIC (control, C), 10%ZrO2NPsGIC (T1) and 10%ZrO2MPsGIC (T2) were prepared per the manufacturer’s instructions (hand-mixed, P/L = 3.4:1 w/w%). Dulbecco’s modified Eagle’s medium (DMEM) was used as the culture medium for HGFs and for eluate preparation. Eluates were collected from all specimens (n = 5/g, 5 × 2 mm) after 24 h and used for XTT to obtain the EC50 using Graph Pad Prism4. A γ-H2AX immunofluorescence assay was performed to detect DSBs in HGFs. The mean foci per cells and percentage of free foci cells were statistically compared (one-way ANOVA with Tamhane’s post hoc and Chi-square respectively) (p < 0.05).Results
(1) EC50 ranged from 31 to 36%. 5% and 20% eluate concentrations were selected for the genotoxicity test. (2) Cells exposed to eluates from T1 had lower mean foci per cell than cells in T2 and C eluates (p < 0.05). Only cells in T1 at 5% had lower mean foci cell than medium (p < 0.05). (3) T1 and C at both concentration showed a higher, but not significant, percentage of free foci cells than negative control (medium). At 20% eluate concentration T2 had a lower percentage of free foci cells than C (p < 0.05).Significance
Nano-zirconia GIC and micro-zirconia GIC were formulated. GIC and both zirconia modified GICs had no genotoxic effect on HGFs in vitro. Further studies related to physical properties should be performed to determine the future clinical applications for these novel nanomaterials. 相似文献3.
M.C. Sánchez M. Toledano-Osorio J. Bueno E. Figuero M. Toledano A.L. Medina-Castillo R. Osorio D. Herrera M. Sanz 《Dental materials》2019,35(1):156-168
Objective
to study the antibacterial effect of polymeric PolymP-n Active nanoparticles using an in vitro subgingival biofilm model.Methods
Hydroxyapatite discs coated with five modalities of nanoparticles (NPs): NPs, NPs doped with zinc, calcium, silver and doxycycline, PBS as control, and Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were studied in a static in vitro biofilm model (12, 24, 48, and 72 h). Nano-roughness of the different disc surfaces (SRa, in nm) and morphological characteristic of the biofilms (thickness (μm) and bacterial viability) were studied by different microscopy modalities. Quantitative Polymerase Chain Reaction was used to assess the effect of the nanoparticles on the bacterial load (colony forming unit per milliliter) (CFU mL?1). Analysis of variance and post-hoc testing with T3 Dunnett?s, and Student Newman Keuls correction was used. Results were considered statistically significant at p < 0.05.Results
Surfaces containing the different nanoparticles showed significant increments in roughness when compared to controls (p < 0.05). A similar biofilm formation and dynamics was observed, although reductions in bacterial viability were detected in biofilms in contact with the different nanoparticles, more pronounced with silver and doxycycline NPs. Doxycycline-NPs biofilms resulted in unstructured biofilm formation and significantly lower number of the six species when compared with the other nanoparticles specimens and controls (p < 0.001 in all cases).Significance
Polymeric PolymP-n Active nanoparticles when combined with silver and doxycycline showed a significant antibacterial effect when tested in an in vitro subgingival biofilm model. 相似文献4.
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5.
Heloisa N. Pantaroto Antonio P. Ricomini-Filho Martinna M. Bertolini José Humberto Dias da Silva Nilton F. Azevedo Neto Cortino Sukotjo Elidiane C. Rangel Valentim A.R. Barão 《Dental materials》2018,34(7):e182-e195
Objective
Titanium dioxide (TiO2) incorporation in biomaterials is a promising technology due to its photocatalytic and antibacterial activities. However, the antibacterial potential of different TiO2 crystalline structures on a multispecies oral biofilm remains unknown. We hypothesized that the different crystalline TiO2 phases present different photocatalytic and antibacterial activities.Methods
Three crystalline TiO2 films were deposited by magnetron sputtering on commercially pure titanium (cpTi), in order to obtain four groups: (1) machined cpTi (control); (2) A-TiO2 (anatase); (3) M-TiO2 (mixture of anatase and rutile); (4) R-TiO2 (rutile). The morphology, crystalline phase, chemical composition, hardness, elastic modulus and surface free energy of the surfaces were evaluated. The photocatalytic potential was assessed by methylene blue degradation assay. The antibacterial activity was evaluated on relevant oral bacteria, by using a multispecies biofilm (Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum) formed on the treated titanium surfaces (16.5 h) followed by UV-A light exposure (1 h) to generate reactive oxygen species production.Results
All TiO2 films presented around 300 nm thickness and improved the hardness and elastic modulus of cpTi surfaces (p < 0.05). A-TiO2 and M-TiO2 films presented superior photocatalytic activity than R-TiO2 (p < 0.05). M-TiO2 revealed the greatest antibacterial activity followed by A-TiO2 (≈99.9% and 99% of bacterial reduction, respectively) (p < 0.001 vs. control). R-TiO2 had no antibacterial activity (p > 0.05 vs. control).Significance
This study brings new insights on the development of extra oral protocols for the photocatalytic activity of TiO2 in oral biofilm-associated disease. Anatase and mixture-TiO2 showed antibacterial activity on this oral bacterial biofilm, being promising surface coatings for dental implant components. 相似文献6.
Berdan Aydin Ariene A. Leme-Kraus Cristina M.P. Vidal Thaiane R. Aguiar Rasika S. Phansalkar Joo-Won Nam James B. McAlpine Shao-Nong Chen Guido F. Pauli Ana K. Bedran-Russo 《Dental materials》2019,35(2):328-334
Objectives
The interactivity of proanthocyanidins (PACs) with collagen modulates dentin matrix biomechanics and biostability. Herein, PAC extracts selected based on structural diversity were investigated to determine key PAC features driving sustained effects on dentin matrices over a period of 18 months.Methods
The chemical profiles of PAC-rich plant sources, Pinus massoniana (PM), Cinnamomum verum (CV) and Hamamelis virginiana (HV) barks, as well as Vitis vinifera (VV) seeds, were obtained by diol HPLC analysis after partitioning of the extracts between methyl acetate and water. Dentin matrices (n = 15) were prepared from human molars to determine the apparent modulus of elasticity over 18 months of aging. Susceptibility of the dentin matrix to degradation by endogenous and exogenous proteases was determined by presence of solubilized collagen in supernatant, and resistance to degradation by bacterial collagenase, respectively. Data were analyzed using ANOVA and Games–Howell post hoc tests (α = 0.05).Results
After 18 months, dentin matrices modified by PM and CV extracts, containing only non-galloylated PACs, were highly stable mechanically (p < 0.05). Dentin matrices treated with CV exhibited the lowest degradation by bacterial collagenase after 1 h and 18 months of aging (p < 0.05), while dentin matrices treated with PM showed the least mass loss and collagen solubilization by endogenous enzymes over time (p < 0.05).Significance
Resistance against long-term degradation was observed for all experimental groups; however, the most potent and long-lasting dentin biomodification resulted from non-galloylated PACs. 相似文献7.
Christina Boutsiouki Roland Frankenberger Susanne Lücker Norbert Krämer 《Dental materials》2019,35(3):422-433
Objective
To investigate secondary caries inhibition after dentine pre-treatment with 2% CHX, experimental addition of CHX in primer and adhesive of a 3-step adhesive system, and industrial addition od CHX in a 2-step adhesive system.Materials and method
Sixty Class-V cavities were restored according to the adhesive protocol (n = 12): 1) control group, Scotchbond Multi-Purpose, 3M (CTRL), 2) 2% CHX dentine pre-treatment (DENT), 3) 0.1% CHX in primer (PRIM), 4) 0.1% CHX in bonding agent (BOND), 5) Peak Universal Bond including 0.2% CHX (PEAK). Specimens were thermocycled (10,000 cycles) and inserted into a Streptococcus mutans biofilm artificial mouth (caries model). The 10-day biological loading protocol consisted of consecutive phases of demineralisation (1 h) and remineralisation (5 h). Evaluation under a fluorescence microscope (demineralisation) and an SEM (marginal gap) followed, at restoration margins, and at 0.3 mm and 0.5 mm distance from the margins, in enamel and in dentine. Total demineralization was calculated as the sum of demineralisation and substance loss due to demineralisation.Results
PRIM (p = 0.007, mod. LSD), BOND (p = 0.012, mod. LSD) and PEAK (p = 0.008, mod. LSD) exhibited significantly higher total demineralisation values in enamel margins than CTRL. No significant differences were noted for total demineralisation in dentine. Regarding marginal gaps, DENT exhibited significantly lower enamel gap values compared to all other groups (p = 0.001).Conclusions
2% CHX as dentine pre-treatment, 0.1% or 0.2% CHX added in adhesives did not provide any antibacterial effect regarding secondary caries in dentine. On the other hand, 2% CHX dentine pre-treatment managed to limit marginal gap formation in enamel compared to the other adhesive protocols in the study. 相似文献8.
María M. Pérez Luis Javier Herrera Francisco Carrillo Oscar E. Pecho Diana Dudea Cristina Gasparik Razvan Ghinea Alvaro Della Bona 《Dental materials》2019,35(2):292-297
Objective
To determine the visual whiteness thresholds for esthetic dentistry using the whiteness index for dentistry based on CIELAB color space (WID).Methods
A total of 60 observers (Dentists and Laypersons; n = 30) from three research sites participated in the study. A psychophysical experiment based on visual assessments of simulated images of teeth on a calibrated display was performed. Images of simulated upper central incisors (SUCI) were consecutively displayed in pairs (60) and the whiteness of each SUCI pair was compared. WID was used to calculate the visual thresholds (WPT- perceptibility threshold; and WAT- acceptability threshold) with 95% confidence intervals (CI) and a Takagi-Sugeno-Kang (TSK) Fuzzy Approximation model was used as fitting procedure. Data was statistical analyzed using paired t-test (α= 0.05).Results
WPT and WAT were 0.72 (CI: 0.0–2.69; r2 = 0.52) and 2.62 (CI: 0.2-7+; r2 = 0.57) WID units, respectively. Significant differences (p < 0.05) were found between WPT and WAT, and between dentist (WPT = 0.46WID units; WAT = 2.20 WID units) and layperson (WPT = 0.94 WID units; WAT = 2.95 WID units).Significance
The visual whiteness difference thresholds determined with WID index can serve as reference values for research and manufacturing of dental materials, and for clinical practice situations such as assessing the effectiveness of bleaching treatments. 相似文献9.
Yasaman Delaviz Timothy W. Liu Ashley R. Deonarain Yoav Finer Babak Shokati J. Paul Santerre 《Dental materials》2019,35(2):229-243
Objective
Antimicrobial oligomers synthesized from ciprofloxacin (CF) and metronidazole (MN) were investigated for their potential use in dental adhesives.Methods
Susceptibility of the cariogenic bacterium Streptococcus mutans UA159 to CF, MN, and CF/MN combination was evaluated. Hydrolytic stability and drug release from the oligomers was studied in buffer and simulated human salivary esterase conditions. Cytotoxicity of films with 15 wt% drug oligomers co-polymerized with commercial monomers were assessed using human gingival fibroblasts (HGFs). In-house adhesives were prepared and characterized for viscosity. Polymerized films were analysed for gel content and water swelling. Interfacial fracture toughness (KIC) of composites bonded to dentin by either a 2 or 3-step etch-and-rinse approach using the in-house formulated adhesives was measured.Results
The respective minimum inhibitory concentration for CF and MN against S. mutans was 0.7 and 2400 μg/mL, with the combination having an additive effect (0.35 μg/mL CF with 1200 μg/mL MN). Antibiotics were released upon hydrolysis of the oligomers. Films containing the drug oligomers were not cytotoxic against HGFs. Replacing 2-hydroxyethyl methacrylate with the drug oligomers increased the viscosity of the experimental adhesives, reduced gel content, and decreased swelling of films in water. Antimicrobial adhesives demonstrated bonding to dentin with interfacial KIC values comparable to the in-house control in the 2-step application, and with slightly lower KIC values in the 3-step approach.Significance
The antimicrobial oligomers can be incorporated into dental adhesive systems using formulations that show comparable fracture toughness to commercial materials, and may provide a means to deliver local antimicrobial drug release at the marginal interface. 相似文献10.
F.J. Rodríguez-Lozano M. Collado-González C.J. Tomás-Catalá D. García-Bernal S. López R.E. Oñate-Sánchez J.M. Moraleda L. Murcia 《Dental materials》2019,35(1):114-124
Objectives
To evaluate in vitro the cementogenic potential and the biological effects of GuttaFlow Bioseal, GuttaFlow 2, MTA Fillapex and AH Plus on human periodontal ligament stem cells (hPDLSCs).Methods
Cell viability, cell migration and cell morphology assays were performed using eluates of each material. To evaluate cell attachment, hPDLSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy (SEM). The effects of endodontic sealers on cementum protein 1 (CEMP1), cementum-derived attachment protein (CAP), bone sialoprotein (BSP), ameloblastin (AMBN), amelogenin (AMELX) and alkaline phosphatase (ALP) gene expression on hPDLSCs were investigated by qPCR and immunofluorescence (IF). Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α < 0.05).Results
More than 90% of viable cells were obtained using extracts of GuttaFlow Bioseal and GuttaFlow2 after 72 h of culture. By contrast, AH Plus and MTA Fillapex induced significantly lower levels of cell viability. GuttaFlow2 and GuttaFlow Bioseal promoted wound closure in a concentration-dependent manner, comparable to that observed with control extracts (*p < 0.05). However, with AH Plus and MTA Fillapex, cell migration was significantly lower than in the control (***p < 0.0001). SEM analysis pointed to an organized stress fiber assembly and high degree of cell adhesion on GuttaFlow Bioseal disks but low rates on GuttaFlow2, MTA Fillapex and AH Plus. When hPDLSCs were cultured with GuttaFlow Bioseal-conditioned media, qPCR assays and IF showed a higher level of AMELX, AMBN, CEMP1 and CAP expression than the control (*p < 0.05)), whereas no such expression was observed in the other sealers.Significance
Our results showed that GuttaFlow sealers were more cytocompatible than AH Plus and MTA Fillapex, while GuttaFlow Bioseal favored cementoblast differentiation of hPDLSCs in the absence of any growth factors. 相似文献11.
Effect of indirect restorative material and thickness on light transmission at different wavelengths
Rafael Rocha Pacheco Adriana Oliveira Carvalho Carolina Bosso André Ana Paula Almeida Ayres Renata Bacelar Catanhede de Sá Tiago Monteiro Dias Frederick Allen Rueggeberg Marcelo Giannini 《Journal of prosthodontic research》2019,63(2):232-238
Purpose
The aim of this study was to evaluate the influence of indirect restorative material type and thickness on the transmission of different wavelengths from a broad-banded dental curing light.Methods
Four dental indirect restorative materials for computer-aided design and computer-aided manufacturing (CAD/CAM) were evaluated: [RC] resin/ceramic hybrid material (Lava Ultimate), [FC] feldspathic ceramic (VitaBlocs), and two zirconia-based ceramics ([ZK] Katana; and [ZL] Lava). Total loss of irradiance (TL) was measured for blue (WB, 425–490 nm) and violet (WV, 350–425 nm) wavelengths. Specimens of 15 × 15 mm with varying thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were fabricated (n = 5). A plasma-arc dental light-curing unit was used (Arc Light-II). To assess TL as a function of wavelength, a software (Spectra Suite v5.1) connected to a spectroradiometer (USB2000) and an integrating sphere (CTSM-LSM-60-SF) was used. Data was subjected to statistical analysis (two-way ANOVA and post-hoc Tukey test, α = 0.05).Results
A 0.5 mm interposition resulted in TL from 50.5 to 67.2%, depending on material. Increased thickness resulted in higher TL for all materials. FC showed less TL compared to ZK. In general, WV showed higher TL than did WB, and WV/WB proportion decreased with increasing thickness.Conclusions
Indirect materials significantly reduced TL, and this effect is greater with increasing thickness. WV showed lower penetration compared to WB. 相似文献12.
Objective
Applicability and stickiness of dental composites are influential factors for the properties of those materials and so indirectly affect function, longevity and esthetics of composite restorations in the clinic. Thus, this in vitro study aimed for the influence of different placement instruments’ diameter, geometries and coatings on the handling of uncured resin composite materials.Methods
A survey about application technique of resin composites, placement instrument diameter, geometry and coating, and application temperature was answered by 55 German dentists in private practice. Due to these data diverse composite placement instruments were used to perform tensile tests on PMMA plates with application forces of 1 N and 2 N (v = 35 mm/min) at 25 and 37 °C. Following the dosing of a certain amount of the composite (nanohybrid, microhybrid) to the tip of the composite placement instrument, unplugging forces were determined after application and unplugging was performed.Results
Unplugging forces were statistically significant different and varied between 0.27 N and 1.14 N. Stickiness of dental composites was dependent on the composite material itself as well as diameter, geometry and coating of the placement instruments.Significance
Pre-clinical testing of composite materials’ stickiness by unplugging forces facilitates the assessment of its handling properties. 相似文献13.
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14.
Tim Joda Benjamin Voumard Philippe K. Zysset Urs Brägger Marco Ferrari 《Journal of prosthodontic research》2018,62(2):258-263
Purpose
The aims were to analyze stiffness, ultimate force, and failure modes of a 2-piece zirconium dioxide (ZrO2) implant system.Methods
Eleven 2-piece ZrO2 implants, each mounted with ZrO2 abutments plus bonded monolithic lithium disilicate (LS2) restorations, were grouped for 3.3 mm (A) and 4.1 mm (B) diameter samples. Quasi-static load was monotonically applied under a standardized test set-up (loading configuration according to DIN ISO 14801). The ultimate force was defined as the maximum force that implants are able to carry out until fracture; stiffness was measured as the maximum slope during loading. An unpaired t-test was performed between group A and B for ultimate force and stiffness (p < 0.05).Results
Force-displacement curves revealed statistically homogenous inner-group results for all samples. Failure modes showed characteristic fractures at the neck configuration of the implants independent of the diameter. Mean stiffness was 1099 N/mm (± 192) for group A, and significantly lower compared to group B with 1630 N/mm (± 274) (p < 0.01); whereas mean ultimate force was 348 N (± 53) for group A, and significantly increased for group B with 684 N (± 29) (p < 0.0001).Conclusions
The examined 2-piece ZrO2 implant system mounted to LS2-restorations seems to be a stable unit under in-vitro conditions with mechanical properties compared to loading capacity of physiological force. The metal-free implant reconstructions demonstrated high stiffness and ultimate force under quasi-static load for single tooth replacement under consideration of the dental indication of narrow and standard diameter implants. 相似文献15.
Shruti Vidhawan Agarwalla Kassapa Ellepola Mariana Caldeira Ferraz da Costa Guilhermino José Macêdo Fechine Julien Luc Paul Morin A.H. Castro Neto Chaminda Jayampath Seneviratne Vinicius Rosa 《Dental materials》2019,35(3):403-413
Objective
To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium.Methods
Graphene was deposited on titanium (Control) via a liquid-free technique. The transfer was performed once (TiGS), repeated two (TiGD) and five times (TiGV) and characterized by AFM (n = 10), Raman spectroscopy (n = 10), contact angle and SFE (n = 5). Biofilm formation (n = 3) to Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans was evaluated after 24 h by CV assay, CFU, XTT and confocal microscopy. Statistics were performed by one-way Anova, Tukey’s tests and Pearson’s correlation analysis at a pre-set significance level of 5 %.Results
Raman mappings revealed coverage yield of 82 % for TiGS and ≥99 % for TiGD and TiGV. Both TiGD and TiGV presented FWHM > 44 cm?1 and ID/IG ratio < 0.12, indicating multiple graphene layers and occlusion of defects. The contact angle was significantly higher for TiGD and TiGV (110° and 117°) comparing to the Control (70°). The SFE was lower for TiGD (13.8 mN/m) and TiGV (12.1 mN/m) comparing to Control (38.3 mN/m). TiGD was selected for biofilm assays and exhibited significant reduction in biofilm formation for all microorganisms compared to Control. There were statistical correlations between the high contact angle and low SFE of TiGD and decreased biofilm formation.Significance
TiGD presented high quality and coverage and decreased biofilm formation for all species. The increased hydrophobicity of graphene films was correlated with the decreased biofilm formation for various species. 相似文献16.
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17.
Marianne Salas Cristina Lucena Luis Javier Herrera Ana Yebra Alvaro Della Bona María M. Pérez 《Dental materials》2018,34(8):1168-1174
Objective
To determine the translucency acceptability and perceptibility thresholds for dental resin composites using CIEDE2000 and CIELAB color difference formulas.Methods
A 30-observer panel performed perceptibility and acceptability judgments on 50 pairs of resin composites discs (diameter: 10 mm; thickness: 1 mm). Disc pair differences for the Translucency Parameter (ΔTP) were calculated using both color difference formulas (ΔTP00 ranged from 0.11 to 7.98, and ΔTPab ranged from 0.01 to 12.79). A Takagi–Sugeno–Kang (TSK) Fuzzy Approximation was used as fitting procedure. From the resultant fitting curves, the 95% confidence intervals were estimated and the 50:50% translucency perceptibility and acceptability thresholds (TPT and TAT) were calculated. Differences between thresholds were statistically analyzed using Student t tests (α = 0.05).Results
CIEDE2000 50:50% TPT was 0.62 and TAT was 2.62. Corresponding CIELAB values were 1.33 and 4.43, respectively. Translucency perceptibility and acceptability thresholds were significantly different using both color difference formulas (p = 0.01 for TPT and p = 0.005 for TAT). CIEDE2000 color difference formula provided a better data fit than CIELAB formula.Significance
The visual translucency difference thresholds determined with CIEDE2000 color difference formula can serve as reference values in the selection of resin composites and evaluation of its clinical performance. 相似文献18.
Objective
To measure the effect of simulated human salivary esterases (SHSE) and metalloproteinases (MMP) inhibition on the integrity of restoration–tooth interfaces made from traditional or polyacid-modified resin composites bonded to human dentin by either total-etch or self-etch adhesives.Methods
Resin–dentin specimens, made from traditional (Z250) or polyacid-modified (Dyract-eXtra) composites were bonded to human dentin using total-etch (TE-Scotchbond) or self-etch (SE-EasyBond) adhesives. TE was applied with or without the MMP inhibitor galardin. Specimens were incubated in phosphate-buffer or SHSE (37 °C/pH = 7.0) for up to 180 days, then suspended in a continuous flow biofilm fermenter cultivating biofilms of Streptococcus mutans UA159. Interfacial bacterial penetration, biofilm biomass and viability were measured by confocal laser scanning microscopy and biomarker dyes and used as interfacial biodegradation markers.Results
All specimens showed increased biofilm penetration and biomass with time regardless of incubation condition. SHSE increased bacterial penetration in all experimental samples after 180 days (p < 0.05). Galardin reduced interfacial bacterial ingress and bacterial biomass vs. non-MMP-inhibited TE-bonded specimens (p < 0.05). TE interfaces showed lower interfacial bacterial biomass vs. SE after 90-day and 180-day (p < 0.05). Dyract-eXtra specimens showed lower bacterial cell viability within the interface vs. Z250 (p < 0.05).Significance
The biodegradation of resin–tooth interfaces is accelerated by esterases, modulated by MMP inhibition and is dependent on the material’s chemistry and mode of adhesion. The in vitro bacterial growth model used in this study facilitates the elucidation of differences in interfacial integrity and biostability between different materials and techniques and is suitable for assessment of their performance prior to clinical evaluation. 相似文献19.
Shaymaa E. Elsaka Amr M. Elnaghy Ayman Mandorah Alaa H. Elshazli 《Dental materials》2019,35(1):185-193
Objective
To evaluate the influence of titanium tetrafluoride (TiF4) incorporation on the physicochemical and antibacterial properties of Biodentine (BD; Septodont, Saint Maur des Faussés, France) as an intraorfice barrier material.Methods
Three different proportions of TiF4 powder were used with BD; 1 wt%, 2 wt%, and 3 wt%; respectively. BD without TiF4 addition was used as the control group. The setting time (ST) was determined using Gillmore needle apparatus. Diametral tensile strength (DTS) and fracture resistance were measured in a universal testing machine. Solubility was assessed using mass variation after 7 days water storage. The hardness test was conducted using Vickers microhardness tester. The antibacterial activity was assessed using direct contact test against Enterococcus faecalis. Radiopacity was assessed and expressed in thickness of aluminum. Surface topography and elemental composition of modified BD were also assessed. The pH of soaking water was measured up to 168 h. Data of tested properties were analyzed using one-way analysis of variance, the paired t-test, two-way repeated measures analysis of variance, and Tukey post hoc tests (P < 0.05).Results
BD-incorporating 2 wt% TiF4 revealed the highest surface microhardness, DTS, and fracture resistance compared with the unmodified group (P < 0.001). Higher concentrations of TiF4 (3 wt%) compromised the solubility and prolonged the ST of BD (P < 0.05). Bacterial growth of BD-incorporating TiF4 was significantly reduced when compared with the control group (P < 0.05). The tested materials induced alkalization of the soaking water that decreased with time.Significance
Biodentine-incorporating TiF4 (1 wt% and 2 wt%) is a promising intraorfice barrier material with enhanced physicochemical and antibacterial properties. 相似文献20.
Chunwoo Lee Satoshi Yamaguchi Keisuke Ohta Satoshi Imazato 《Journal of prosthodontic research》2019,63(1):90-94