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1.
J Adhes Dent ; 23(5): 461-467, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34549929

RESUMO

PURPOSE: To evaluate the microtensile bond strength (µTBS) of a one-step self-etch adhesive (1-SEA) to dentin and its interfacial nanomechanical properties after 8 years of water storage. MATERIALS AND METHODS: Flat coronal dentin surfaces of extracted human third molars were bonded with a 1-SEA (Clearfil S3 Bond Plus, CS3+) and built up with a hybrid resin composite (Clearfil AP-X). After storage in water for 24 h or 8 years, non-trimmed stick-shaped specimens were fabricated from the central part of each bonded tooth and subjected to the µTBS test at a crosshead speed of 1.0 mm/min. Failure modes and the morphology of debonded interfaces were analyzed using a scanning electron microscope (SEM). In addition, the elastic modulus (E) and hardness (H) of the adhesive layer and the resin composite were determined by an instrumented nanoindentation test. The acquired µTBS, E, and H data were statistically analyzed using t-tests to examine the effect of storage time (α = 0.05). RESULTS: The 8-year µTBS was slightly lower than that after 24 h, but the difference was not significant (p = 0.123). The SEM observation of debonded surfaces after 8 years revealed extrusions and lacunas. E and H of the adhesive layer and the resin composite significantly decreased over the 8-year water storage (p < 0.001). CONCLUSIONS: Although 8 years of water storage did not decrease the µTBS of CS3+ significantly, the observed failure mode patterns and significantly decreased nanomechanical properties indicated resin degradation of the adhesive and the resin composite.


Assuntos
Colagem Dentária , Dentina , Resinas Compostas , Cimentos Dentários , Análise do Estresse Dentário , Adesivos Dentinários , Humanos , Teste de Materiais , Cimentos de Resina , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração
2.
Biomed Res Int ; 2021: 9987860, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34195290

RESUMO

Purpose: The potential of UV-mediated photofunctionalization to enhance the resin-based luting agent bonding performance to aged materials was investigated. Methods: Sixty samples of each material were prepared. Yttria-stabilized zirconia (YZr) and Pd-Au alloy (Pd-Au) plates were fabricated and sandblasted. Lithium disilicate glass-ceramic (LDS) was CAD-CAM prepared and ground with #800 SiC paper. Half of the specimens were immersed in machine oil for 24 h to simulate the carbon adsorption. Then, all of the specimens (noncarbon- and carbon-adsorbed) were submitted to UV-mediated photofunctionalization with a 15 W UV-LED (265 nm, 300 mA, 7692 µW/cm2) for 0 (control groups), 5, and 15 min and subjected to contact angle (Ɵ) measurement and bonded using a resin cement (Panavia™ V5, Kuraray Noritake, Japan). The tensile bond strength (TBS) test was performed after 24 h. The Ɵ (°) and TBS (MPa) data were statistically analyzed using two-way ANOVA and Bonferroni correction tests (α = 0.05). Results: In the carbon-adsorbed groups, UV-mediated photofunctionalization for 5 min significantly decreased Ɵ of all materials and increased TBS of YZr, and UV for 15 min significantly increased the TBS of LDS and Pd-Au. In noncarbon-adsorbed groups, UV-photofunctionalization did not significantly change the Ɵ or TBS except YZr specimens UV-photofunctionalized for 15 min. Conclusion: UV-mediated photofunctionalization might have removed the adsorbed hydrocarbon molecules from the materials' surfaces and enhanced bond strengths of Panavia™ V5 to YZr, LDS, and Pd-Au. Additionally, UV-mediated photofunctionalization improved the overall TBS of YZr. Further investigation on the optimum conditions of UV photofunctionalization on indirect restorative materials should be conducted.

3.
J Adhes Dent ; 23(4): 327-334, 2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34269543

RESUMO

PURPOSE: The effect of surface moisture on bur-cut dentin on the microtensile bond strength (µTBS) of universal adhesives with various contents of 2-hydroxyethyl methacrylate (HEMA) and methacrylamide monomers was evaluated. MATERIALS AND METHODS: Flat mid-coronal dentin surfaces of human molars were exposed, and a standardized smear layer was prepared using a fine-grit diamond bur. The surfaces were either left wet or air dried for 10 s before bonding with Clearfil Universal Bond Quick (UBQ), experimental UBQ without an amide monomer (UBQexp), Scotchbond Universal (SBU), Prime&Bond Universal (PBU), or BeautiBond Universal (BBU). The specimens were built up with resin composite, sectioned into sticks and subjected to the µTBS test after 24 h or 10,000 thermal cycles. The µTBS data were analyzed using three-way ANOVA followed by pairwise comparisons with Bonferroni's correction (α = 0.05). RESULTS: The level of dentin moisture did not significantly affect µTBS of UBQ and BBU (p > 0.05). HEMA-containing UBQ, UBQexp, and SBU exhibited higher µTBS to dry dentin, while HEMA-free PBU and BBU showed higher µTBS to wet dentin. Thermocycling significantly decreased the µTBS of UBQexp (p < 0.01) and BBU (p < 0.001) irrespective of dentin moisture level, while SBU was significantly affected only on dry dentin (p < 0.001). Thermocycling had no significant effect on UBQ and PBU containing methacrylamide monomers (p > 0.05). CONCLUSION: Dry surfaces enabled obtaining optimal bonding for HEMA-containing adhesives to bur-cut dentin, while wet surfaces enabled optimal bonding for HEMA-free adhesives. Methacrylamide monomers could contribute to the improvement of the initial and long-term bonding performance of universal adhesives to bur-cut dentin.


Assuntos
Colagem Dentária , Adesivos Dentinários , Acrilamidas , Adesivos , Resinas Compostas , Cimentos Dentários , Dentina , Humanos , Teste de Materiais , Metacrilatos , Cimentos de Resina , Resistência à Tração
4.
Dent Mater J ; 2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34305051

RESUMO

The effect of long-term water storage on the regional ultimate tensile strength (UTS), water sorption (Wsp) and water solubility (Wsl) of conventional and bulk-fill resin composites at various depths was investigated. Composite specimens light-cured from one side were sectioned into beams corresponding to different depths (1-5 mm) and stored in water for 24 h, 1 week, 1 month, 6 months or 1 year. UTS increased during the first week and then gradually decreased over time, especially in deeper regions. Bulk-fill composites initially exhibited similar UTS at all depths, whereas the UTS of conventional composites at 1 mm and 5 mm differed significantly at all time points. Wsp and Wsl increased with depth and storage time, markedly at 3-5 mm after 1 month for conventional composites and after 6 months for bulk-fill composites. The signs of degradation at depths beyond 3 mm suggested that even bulk-fill composites have suboptimal properties in layers more than 3 mm in thickness.

5.
J Dent ; 109: 103665, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33864887

RESUMO

OBJECTIVES: To evaluate the micro-tensile bond strength (µTBS) of self-etch adhesives (SEA) to normal and caries-affected dentin after smear layer deproteinization with papain enzyme-based and NaOCl-based chemo-mechanical caries removal agents (CRAs) and to compare their efficacy to a 6 % NaOCl solution. METHODS: Forty extracted human molars with occlusal carious lesions were randomly divided into four pretreatment groups: no treatment (control), Papacarie for 60 s, Carisolv for 60 s, and 6 % NaOCl for 15 s. After pretreatment, Universal Bond Quick ER (UBQ, one-step, 1-SEA) or Clearfil SE Bond 2 (CSE, two-step, 2-SEA) was applied to the pre-treated surface, and built-up with resin composite (Clearfil AP-X). The µTBS test was performed after 24 h water storage of the specimens at 37 °C, and the modes of failure were determined under SEM. Deproteinizing effects of the tested agents on smear layer-covered dentin was quantified by changes in the amide:phosphate ratio using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) analysis. RESULTS: On caries-affected dentin the µTBS improved significantly after pretreatment with Papacarie, Carisolv, and 6 % NaOCl with both SEAs (p < 0.05). Papacarie pretreatment significantly improved the µTBS of UBQ on normal dentin compared to NaOCl pretreatment (p < 0.05). ATR-FTIR revealed that all agents significantly decreased the amide:phosphate ratio on the smear layer-covered normal and caries-affected dentin (p < 0.05). CONCLUSIONS: Smear layer deproteinizing with papain enzyme-based and NaOCl-based gel CRAs was effective in improving the micro-tensile bond strength of self-etch adhesives to caries-affected dentin. CLINICAL SIGNIFICANCE: Smear layer deproteinization with Papacarie (a papain enzyme-based gel) or Carisolv (a NaOCl-based gel) can improve the µTBS to normal and caries-affected dentin bonded with 2-step self-etch adhesives.


Assuntos
Colagem Dentária , Cárie Dentária , Adesivos Dentinários , Resinas Compostas , Cimentos Dentários , Dentina , Humanos , Técnicas In Vitro , Teste de Materiais , Dente Molar , Distribuição Aleatória , Cimentos de Resina , Resistência à Tração
6.
Dent Mater J ; 40(4): 1033-1040, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33883353

RESUMO

This study evaluated the effect of the structural color phenomenon in resin composites (RCs) on the color adjustment of restorations by investgating their color reproduction performance in human incisors of various shade. Cervical cavities were filled with a single-shade RC with 260 nm spherical fillers (Omnichroma (OMN)), conventional A2-shade RCs (Estelite Σ Quick or Clearfil AP-X), or experimental RCs with 5-50 nm fumed silica fillers (R1) and 100 nm spherical fillers (R2). Color parameters (L*C*h*) were measured using a CIE XYZ camera along the centerline of the restorations, and the color difference (∆E00) between corresponding areas of intact and restored teeth was calculated. Additionally, the reflectance spectra of OMN, R1, and R2 were investigated. OMN exhibited significantly lower ∆E00 than other tested RCs (p<0.05) and its reflection spectrum ranged from blue to red, while a blue peak was observed with R1 and R2, indicating a higher color adjustment potential of OMN.


Assuntos
Resinas Compostas , Cor , Humanos
7.
Dent Mater J ; 40(4): 877-884, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33678732

RESUMO

The influence of sulfinate agents applied as a dentin pretreatment or a mixture with multi-mode one-step self-etch adhesives (1-SEAs) on the degree of conversion (DC) and micro-tensile bond strength (µTBS) of light-cured 1-SEAs was investigated. 1-SEAs Clearfil Universal Bond Quick (UBQ) or Scotchbond Universal Adhesive (SBU) were applied to dentin in etch&rinse or self-etch mode using various application strategies: 1) no pretreatment, 2) pretreatment with 90 wt% ethanol, 3) pretreatment with a sulfinate agent Clearfil DC Activator (UDC) or Scotchbond Universal DCA (SDC), or 4) a mixture of UBQ+UDC or SBU+SDC. µTBS was measured after 24 h. Additionally, DC was measured using attenuated total reflectance Fourier-transform infrared spectroscopy. Pretreatment with sulfinate agents resulted in the highest µTBS and DC, significantly improving them especially in etch&rinse mode. The mixture of sulfinate agents with 1-SEAs was less effective. Pretreatment with ethanol significantly improved µTBS in etch&rinse mode but compromised µTBS in self-etch mode.


Assuntos
Colagem Dentária , Adesivos , Resinas Compostas , Cimentos Dentários , Dentina , Adesivos Dentinários , Teste de Materiais , Cimentos de Resina , Resistência à Tração
8.
J Prosthet Dent ; 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33431177

RESUMO

STATEMENT OF PROBLEM: The bonding of light-activated adhesives to root canal dentin with an additional touch-polymerization activator has been insufficiently examined. PURPOSE: The purpose of this in vitro study was to investigate the effect of touch-polymerization activators and extended light-irradiation time on the microtensile bond strength (µTBS) of light-activated adhesives. MATERIAL AND METHODS: Post cavities were prepared in 50 extracted mandibular premolars and bonded using Prime&Bond Universal (PBU); PBU+Self Cure Activator (SCA); Clearfil SE Bond 2 (SEB); SEB+Clearfil DC Activator (DCA); or Clearfil Universal Bond Quick ER (UBQ). After light-irradiation for 10 or 20 seconds, the post cavities were filled with dual-activated resin core materials. Eight beams were prepared per specimen and subjected to the µTBS test. The µTBS data were analyzed by using 3-way ANOVAs with the Bonferroni correction (α=.05). RESULTS: The 3-way ANOVAs indicated that the use of touch-polymerization activators (SCA and DCA) significantly increased the µTBS of PBU and SEB in both the coronal (P=.015) and apical (P=.001) regions. The extension of light-irradiation time to 20 seconds significantly improved their µTBS in the apical region (P<.001), but not in the coronal region (P=.09). Light-irradiation for 20 seconds increased the µTBS of UBQ significantly in the coronal region (P=.014). CONCLUSIONS: Touch-polymerization activators improved the bond strength of light-activated adhesives to root canal dentin, especially when combined with an extended light-irradiation time.

9.
Dent Mater J ; 40(2): 379-384, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33100300

RESUMO

The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).


Assuntos
Colagem Dentária , Silanos , Cerâmica , Cimentos Dentários , Porcelana Dentária , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície
10.
Dent Mater J ; 40(2): 446-454, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33162459

RESUMO

The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain (FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.


Assuntos
Colagem Dentária , Cimentos de Resina , Cimentos Dentários , Esmalte Dentário , Dentina , Adesivos Dentinários , Teste de Materiais , Resistência à Tração
11.
Plant J ; 105(4): 1026-1034, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33211343

RESUMO

Ectopic expression of the apple 2-oxoglutarate-dependent dioxygenase (DOX, 2ODD) gene, designated MdDOX-Co, is thought to cause the columnar shape of apple trees. However, the mechanism underlying the formation of such a unique tree shape remains unclear. To solve this problem, we demonstrated that Arabidopsis thaliana overexpressing MdDOX-Co contained reduced levels of biologically active gibberellin (GA) compared with wild type. In summary: (i) with biochemical approaches, the gene product MdDOX-Co was shown to metabolize active GA A4 (GA4 ) to GA58 (12-OH-GA4 ) in vitro. MdDOX-Co also metabolized its precursors GA12 and GA9 to GA111 (12-OH-GA12 ) and GA70 (12-OH-GA9 ), respectively; (ii) Of the three 12-OH-GAs, GA58 was still active physiologically, but not GA70 or GA111 ; (iii) Arabidopsis MdDOX-Co OE transformants converted exogenously applied deuterium-labeled (d2 )-GA12 to d2 -GA111 but not to d2 -GA58 , whereas transformants converted applied d2 -GA9 to d2 -GA58 ; (iv) GA111 is converted poorly to GA70 by GA 20-oxidases in vitro when GA12 is efficiently metabolized to GA9 ; (v) no GA58 was detected endogenously in MdDOX-Co OE transformants. Overall, we conclude that 12-hydroxylation of GA12 by MdDOX-Co prevents the biosynthesis of biologically active GAs in planta, resulting in columnar phenotypes.


Assuntos
Genes de Plantas/genética , Giberelinas/metabolismo , Malus/genética , Reguladores de Crescimento de Plantas/metabolismo , Árvores/genética , Arabidopsis , Dioxigenases/metabolismo , Genes de Plantas/fisiologia , Ácidos Cetoglutáricos/metabolismo , Malus/crescimento & desenvolvimento , Malus/metabolismo , Malus/fisiologia , Reguladores de Crescimento de Plantas/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Árvores/crescimento & desenvolvimento , Árvores/metabolismo , Árvores/fisiologia
12.
Dent Mater J ; 40(2): 385-392, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33208575

RESUMO

This study aimed to evaluate the effect of silane coupling agent contamination on the microtensile bond strength (µTBS) of 3-step etch-and-rinse adhesives on dentin. Flat occlusal dentin surfaces were prepared and randomly divided into 8 groups (n=20) based on the tested adhesives; Scotchbond Multi-purpose or Optibond FL, with contamination of an experimental silane (2 vol% of 3-m ethacryloxypropyltrimethoxysilane at pH 4.5) before acid-etching, after-etching or after-priming; while the groups without silane contamination served as controls. µTBS data were analyzed by two-way ANOVA and Tukey's HSD tests at a significance level of 0.05. Additional specimens of contaminated dentin were used to analyze changes in the organic molecules by Fourier transform infrared spectroscopy (FTIR). Silane contamination before acid-etching did not significantly change µTBS (p>0.05), but contamination after-etching and after-priming significantly decreased µTBS of both adhesives (p<0.05). Silane contamination had an adverse effect on the dentin bond strength of 3-step etch-and-rinse adhesives especially after-priming.


Assuntos
Colagem Dentária , Adesivos Dentinários , Adesivos , Resinas Compostas , Cimentos Dentários , Dentina , Teste de Materiais , Cimentos de Resina , Silanos , Resistência à Tração
13.
Dent Mater J ; 40(3): 599-605, 2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-33361663

RESUMO

The effect of 1-week water storage and subsequent 10,000 thermal cycles on light transmission properties (straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV)), translucency parameter (TP) and refractive index (RI) of four nanofilled flowable composites was examined. The composites included Filtek Supreme Ultra Flowable Restorative (FSU), Estelite Flow Quick (EFQ), Estelite Universal Flow, (EUF), and Clearfil Majesty ES Flow (ESF), all of A3 shade. For composites with lower filler load (FSU, EFQ), water storage increased G0, AV and TP, but subsequent thermocycling decreased them. An opposite tendency was found for DF. Materials with higher filler load (EUF, ESF) were not significantly affected by aging conditions. RI of EFQ and EUF containing bisphenol A polyethoxy methacrylate (Bis-MPEPP) increased significantly after thermocycling. Additionally, morphological changes were observed using scanning electron microscopy which revealed cracks within nanocluster fillers and dislocation of particles in FSU and EFQ after thermocycling.


Assuntos
Refratometria , Água , Resinas Compostas , Materiais Dentários , Luz , Teste de Materiais , Metacrilatos , Microscopia Eletrônica de Varredura , Propriedades de Superfície
15.
Plant Cell Physiol ; 61(11): 1861-1868, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33057650

RESUMO

Plants synthesize gibberellin (GA), a diterpenoid hormone, via ent-kaurenoic acid (KA) oxidation. GA has not been detected in the moss Physcomitrium patens despite its ability to synthesize KA. It was recently shown that a KA metabolite, 3OH-KA, was identified as an active regulator of protonema differentiation in P. patens. An inactive KA metabolite, 2OH-KA, was also identified in the moss, as was KA2ox, which is responsible for converting KA to 2OH-KA. In this review, we mainly discuss the GA biosynthetic gene homologs identified and characterized in bryophytes. We show the similarities and differences between the OH-KA control of moss and GA control of flowering plants. We also discuss using recent genomic studies; mosses do not contain KAO, even though other bryophytes do. This absence of KAO in mosses corresponds to the presence of KA2ox, which is absent in other vascular plants. Thus, given that 2OH-KA and 3OH-KA were isolated from ferns and flowering plants, respectively, vascular plants may have evolved from ancestral bryophytes that originally produced 3OH-KA and GA.


Assuntos
Bryopsida/crescimento & desenvolvimento , Diterpenos/metabolismo , Células Germinativas Vegetais/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/fisiologia , Evolução Biológica , Bryopsida/metabolismo , Bryopsida/fisiologia , Diterpenos do Tipo Caurano/metabolismo , Células Germinativas Vegetais/metabolismo , Células Germinativas Vegetais/fisiologia , Reguladores de Crescimento de Plantas/metabolismo
16.
J Prosthet Dent ; 2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32800576

RESUMO

A straightforward technique is presented for an interim or short-term definitive esthetic replacement of missing anterior teeth requiring no tooth preparation. Composite resins are injected into transparent silicone indices fabricated from 3-dimensional-printed casts of a digital waxing. The dentin core is formed of a durable short fiber-reinforced injectable composite resin and veneered with an enamel-shade composite resin for enhanced esthetics. Besides being noninvasive, this technique is more straightforward than traditional options, reducing chair time while providing an accurate outcome.

17.
J Esthet Restor Dent ; 32(7): 638-644, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32603555

RESUMO

OBJECTIVE: Restorative treatment of anterior teeth is often required as the final step of orthodontic therapy to optimize the esthetics and function. This case report presents a direct minimally invasive approach for post-orthodontic recontouring of anterior teeth using the composite injection technique with a digital workflow. CLINICAL CONSIDERATIONS: The extraction of central incisors with short roots was indicated to resolve maxillary anterior crowding. The gained space was closed with lateral incisors, and it was necessary to recontour them and canines to resemble central and lateral incisors, respectively. The restorations were digitally designed, and a transparent silicone index was fabricated from a 3D-printed cast of the digital wax-up. After lateral incisors and canines were bonded with a universal adhesive in the etch-and-rinse mode, a highly filled injectable composite resin was applied into the index. The restorative treatment was preceded by gingivectomy using an Er:YAG laser and home bleaching. CONCLUSIONS: In cases where more complex recontouring of anterior teeth is necessary, the composite injection technique could be a suitable alternative to indirect restorations, because it is straightforward, cost-effective, and does not require any preparation. The digital workflow simplified and expedited the treatment while contributing to its precision. CLINICAL SIGNIFICANCE: Post-orthodontic recontouring using direct composite restorations is well accepted by patients due to low cost and non-invasiveness. However, in complicated cases, the free-hand technique is time-consuming and technique-sensitive. The presented composite injection technique with a digital workflow significantly simplifies and expedites the composite placement while predictably enhancing the treatment outcome.


Assuntos
Restauração Dentária Permanente , Fluxo de Trabalho , Resinas Compostas , Estética Dentária , Humanos , Incisivo
18.
Dent Mater J ; 39(5): 892-899, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32448851

RESUMO

The effect of different air-blowing strategies using a prototype of a newly developed clinically applicable warm air-blowing device on the microtensile bond strength (µTBS) of one-step self-etch adhesives (1-SEAs) to human root-canal dentin was evaluated. Post cavities (8 mm depth, 1.5 mm diameter) were prepared and bonded with four 1-SEAs. Air-blowing was performed using normal air (23±1°C) for 10 or 20 s; warm air (60±1°C) for 10 or 20 s; or their combination for 10 s (5 s normal, 5 s warm) or 20 s (10 s normal, 10 s warm). After filling with corresponding core materials and 24-h water storage, µTBS test was performed. For three of the 1-SEAs, combined air-blowing for 20 s significantly increased µTBS compared to other air-blowing strategies (p<0.05). This suggests that the combination of normal and warm air-blowing for 20 s can enhance solvent evaporation from 1-SEAs, thus resulting in their improved bonding performance to root-canal dentin.


Assuntos
Colagem Dentária , Adesivos , Cimentos Dentários , Cavidade Pulpar , Dentina , Adesivos Dentinários , Humanos , Teste de Materiais , Cimentos de Resina , Resistência à Tração
19.
Eur J Oral Sci ; 128(3): 255-262, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32311176

RESUMO

The effect of smear layer-deproteinizing pretreatment using hypochlorous acid (HOCl) on the micro-shear bond strengths (µSBS) of conventional and resin-modified glass-ionomer cements (GIC) to dentin was investigated and compared with demineralizing pretreatment with polyacrylic acid (PAA). Three GICs: Fuji IX GP Extra (restorative conventional GIC), GC Fuji II LC EM (restorative resin-modified GIC), and GC Fuji Luting EX (luting resin-modified GIC), were used. One hundred fifty human molars were divided into groups (n = 10) according to the cements and dentin pretreatments; no pretreatment (control), 10 s PAA pretreatment, and HOCl pretreatment for 5, 15, or 30 s. After 24 h, µSBS was tested and the data were statistically analyzed using a two-way ANOVA, followed by Tukey's post-hoc test. HOCl pretreatment significantly increased µSBS of conventional GIC compared to the control group. For resin-modified restorative GIC, 5 s HOCl deproteinization significantly increased µSBS, while longer application times did not. There was no significant difference between HOCl-pretreated and control groups of resin-modified luting GIC. PAA pretreatment increased the µSBS of all cements significantly. In conclusion, smear layer deproteinization with HOCl can enhance the dentin bonding of conventional GIC. However, the residual radicals may adversely affect the polymerization of resin-modified GICs.


Assuntos
Colagem Dentária , Camada de Esfregaço , Resinas Compostas , Dentina , Cimentos de Ionômeros de Vidro , Humanos , Ácido Hipocloroso , Teste de Materiais , Cimentos de Resina
20.
Tree Physiol ; 40(9): 1205-1216, 2020 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-32333787

RESUMO

The apple cultivar McIntosh Wijcik, which is a mutant of 'McIntosh', exhibits a columnar growth phenotype (short internodes, few lateral branches, many spurs, etc.) that is controlled by a dominant Co gene. The candidate gene (MdDOX-Co), encoding a 2-oxoglutarate-dependent dioxygenase, is located adjacent to an insertion mutation. Non-columnar apples express MdDOX-Co in the roots, whereas columnar apples express MdDOX-Co in the aerial parts as well as in the roots. However, the function of MdDOX-Co remains unknown. Here, we characterized tobacco plants overexpressing MdDOX-Co. The tobacco plants showed the typical dwarf phenotype, which was restored by application of gibberellin A3 (GA3). Moreover, the dwarf tobacco plants had low concentrations of endogenous bioactive gibberellin A1 (GA1) and gibberellin A4 (GA4). Similarly, 'McIntosh Wijcik' contained low endogenous GA4 concentration and its dwarf traits (short main shoot and internodes) were partially reversed by GA3 application. These results indicate that MdDOX-Co is associated with bioactive GA deficiency. Interestingly, GA3 application to apple trees also resulted in an increased number of lateral branches and a decrease in flower bud number, indicating that gibberellin (GA) plays important roles in regulating apple tree architecture by affecting both lateral branch formation (vegetative growth) and flower bud formation (reproductive growth). We propose that a deficiency of bioactive GA by ectopic expression of MdDOX-Co in the aerial parts of columnar apples not only induces dwarf phenotypes but also inhibits lateral branch development and promotes flower bud formation, and assembly of these multiple phenotypes constructs the columnar tree form.


Assuntos
Dioxigenases , Malus/genética , Expressão Ectópica do Gene , Regulação da Expressão Gênica de Plantas , Giberelinas , Fenótipo
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