Dental Materials最新文献

{"title":"Evaluation of the biological effects of amelogenin on human oral keratinocytes","authors":"Iris Frasheri ,&nbsp;Maria Paschalidou ,&nbsp;Thomas Imhof ,&nbsp;Thorsten Steinberg ,&nbsp;Thomas Spinell ,&nbsp;Reinhard Hickel ,&nbsp;Matthias Folwaczny","doi":"10.1016/j.dental.2023.08.176","DOIUrl":"https://doi.org/10.1016/j.dental.2023.08.176","url":null,"abstract":"<div><h3>Objectives</h3><p>Amelogenins are clinically used in periodontal regeneration as main components of root surface modifying agents, even without specifically preventing the premature colonization of the healing tissue defect by means of a physical barrier membrane. The objective of this study was to investigate the effects of human amelogenin on the proliferation, migration, and morphology of Immortalized Human Oral Keratinocytes (iHOKs).</p></div><div><h3>Methods</h3><p>Immortalized Human Oral Keratinocytes were expanded in Keratinocyte Growth Medium-2 (KGM-2). Full-length recombinant amelogenin protein was diluted in KGM-2 in five concentrations (10 ng/ml, 100 ng/ml, 1.000 ng/ml, 5.000 ng/ml and 10.000 ng/ml). iHOKs were cultured in medium supplemented with the amelogenin dilutions. Samples without amelogenin served as control. Cell metabolism and cell proliferation together with cell migration were evaluated at day 7, 14, 21.</p></div><div><h3>Results</h3><p>At day 7, iHOKs treated with 10,000 ng/ml showed a significant decrease in keratinocytes´ proliferation. The metabolic activity at this timepoint was significantly lower for concentrations ≥ 1000 ng/ml. At days 14 and 21, both the addition of 5000 ng/ml and even more 10,000 ng/ml amelogenin reduced significantly the proliferation of keratinocytes. The effects on the metabolic activity for these timepoints were visible already with 100 ng/ml. Treatment of iHOKs with amelogenin of ≥ 1000 ng/ml led to inhibitory effects on cell migration already after 24 h.</p></div><div><h3>Conclusions</h3><p>The full-length recombinant amelogenin has a significant biological impact on iHOKs. The increasing dose dependent inhibitory effects of amelogenin shown on iHOKs might explain the disruption of the apical migration of the junctional epithelium during regenerative healing.</p></div><div><h3>Clinical significance</h3><p>Amelogenin, presents time- and dose-dependent inhibitory effects on the growth of keratinocytes, which might explain the biological rationale behind its application in periodontal regeneration.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 10","pages":"Pages 922-928"},"PeriodicalIF":5.0,"publicationDate":"2023-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"7183345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical behavior of 3D-printed dental restorative resins: Influence of thickness and printing angle","authors":"Cristina Espinar ,&nbsp;Alvaro Della Bona ,&nbsp;Maria Tejada-Casado ,&nbsp;Rosa Pulgar ,&nbsp;María M. Pérez","doi":"10.1016/j.dental.2023.08.003","DOIUrl":"https://doi.org/10.1016/j.dental.2023.08.003","url":null,"abstract":"<div><h3>Objectives</h3><p>To evaluate the influence of thickness and printing angle on the optical properties of 3D-printed dental restorative resins.</p></div><div><h3>Methods</h3><p>Four 3D printing resin systems were evaluated: DFT-Detax Freeprint Temp; FP- Formlabs Permanent Crown; FP- Formlabs Temporary CB; and GCT- GC Temporary-. Samples from each material were printed at 0° and 90°, and polished up to 0.5, 1.0, 1.5 and 2.0 mm thickness. Scattering (S), absorption (K) and albedo (<em>a</em>) coefficients, transmittance (T%), light reflectivity (RI) and infinite optical thickness (<span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span>) were calculated using Kubelka-Munk’s model. Data were statistically analyzed using Kruskal–Wallis¸ Mann-Whitney tests, and VAF coefficient.</p></div><div><h3>Results</h3><p>The spectral distribution on S, K, T%, RI,<span><math><mrow><mspace></mspace><msub><mrow><mi>X</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span> were wavelength dependent. Although the spectral behaviors were similar for all the specimens evaluated, the values of S, K, T% and<span><math><mrow><mspace></mspace><msub><mrow><mi>X</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span> presented significant differences between specimen thicknesses for all the materials used and for both printing orientations. Values for S and K increased, and T% and <span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span> decreased. Significant differences between 0° and 90° were found for RI values at 0.5 and 1.0 mm thick samples, for S and K at 2.0 mm, for <span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span> at 0.5 and 1.0 mm for DFT, and at 0.5 mm for FT.</p></div><div><h3>Conclusions</h3><p>Optical properties of 3D-printed restorative resins vary between thicknesses, and could be affected by the building orientation. Therefore, these factors should be considered in order to improve the biomimetic potential of 3D-printed dental restorative resins.</p></div><div><h3>Clinical significance</h3><p>Understanding the optical behavior of the 3D-printed restorative resins is essential to optimize their clinical performance.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 10","pages":"Pages 894-902"},"PeriodicalIF":5.0,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"7183333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acylthiourea oligomers as promising reducing agents for dimethacrylate-based two-component dental materials","authors":"Yohann Catel,&nbsp;Jörg Angermann,&nbsp;Benjamin Grob,&nbsp;Pascal Fässler,&nbsp;Iris Lamparth,&nbsp;Thomas Schnur","doi":"10.1016/j.dental.2023.07.007","DOIUrl":"https://doi.org/10.1016/j.dental.2023.07.007","url":null,"abstract":"<div><h3>Objectives</h3><p>Currently used thiourea-based two-component dental materials may release bitter compounds if they are not properly cured. To address this issue, the objective of this study was to evaluate the potential of acylthiourea oligomers as reducing agents for the development of self-cure composites.</p></div><div><h3>Methods</h3><p>Acylthiourea oligomers <strong>ATUO1–3</strong> were synthesized via cotelomerization of the acylthiourea methacrylate <strong>ATU1</strong> with butyl methacrylate. They were characterized by ¹H NMR spectroscopy and size exclusion chromatography. Self-cure composites based on the redox initiator system cumene hydroperoxide/acylthiourea oligomer/copper(II) acetylacetonate were formulated. The flexural strength and modulus were measured using a three-point bending setup. The double bond conversions were determined using NIR spectroscopy. The working time of each self-cure composite was measured using an oscillating rheometer. Leaching experiments using light-cure composites were performed in DMSO-d6.</p></div><div><h3>Results</h3><p>Acylthiourea oligomers <strong>ATUO1–3</strong> were successfully synthesized in good yields. Both the oligomer molecular weight and the amount of thiourea groups were varied. Self-cure composites containing <strong>ATUO1</strong> or <strong>ATUO2</strong> as reducing agents exhibited excellent mechanical properties and high double-bond conversions. The amounts of reducing agent, cumene hydroperoxide and copper(II) acetylacetonate were shown to have a significant impact on the working time. Moreover, a correlation between flexural modulus and the amount of metal salt was clearly established. Self-cure composites containing the oligomer <strong>ATUO1</strong> exhibited a longer working time than materials containing <strong>ATU1</strong> or acetylthiourea. Contrary to acetylthiourea, <strong>ATUO1</strong> was not able to leach out of light-cured composites.</p></div><div><h3>Significance</h3><p>Acylthiourea oligomers are promising reducing agents for the formulation of two-component dental materials that do not induce a bitter taste in mouth.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 10","pages":"Pages 886-893"},"PeriodicalIF":5.0,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"7183378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Injectable periodontal ligament stem cell-metformin-calcium phosphate scaffold for bone regeneration and vascularization in rats","authors":"Yaxi Sun ,&nbsp;Zeqing Zhao ,&nbsp;Qingchen Qiao ,&nbsp;Shengnan Li ,&nbsp;Wenting Yu ,&nbsp;Xiuchen Guan ,&nbsp;Abraham Schneider ,&nbsp;Michael D. Weir ,&nbsp;Hockin H.K. Xu ,&nbsp;Ke Zhang ,&nbsp;Yuxing Bai","doi":"10.1016/j.dental.2023.07.008","DOIUrl":"https://doi.org/10.1016/j.dental.2023.07.008","url":null,"abstract":"<div><h3>Objectives</h3><p>Injectable and self-setting calcium phosphate cement scaffold (CPC) capable of encapsulating and delivering stem cells and bioactive agents would be highly beneficial for dental and craniofacial repairs. The objectives of this study were to: (1) develop a novel injectable CPC scaffold encapsulating human periodontal ligament stem cells (hPDLSCs) and metformin (Met) for bone engineering; (2) test bone regeneration efficacy in vitro and in vivo.</p></div><div><h3>Methods</h3><p>hPDLSCs were encapsulated in degradable alginate fibers, which were then mixed into CPC paste. Five groups were tested: (1) CPC control; (2) CPC + hPDLSC-fibers + 0% Met (CPC + hPDLSCs + 0%Met); (3) CPC + hPDLSC-fibers + 0.1% Met (CPC + hPDLSCs + 0.1%Met); (4) CPC + hPDLSC-fibers + 0.2% Met (CPC + hPDLSCs + 0.2%Met); (5) CPC + hPDLSC-fibers + 0.4% Met (CPC + hPDLSCs + 0.4%Met). The injectability, mechanical properties, metformin release, and hPDLSC osteogenic differentiation and bone mineral were determined in vitro. A rat cranial defect model was used to evaluate new bone formation.</p></div><div><h3>Results</h3><p>The novel construct had good injectability and physical properties. Alginate fibers degraded in 7 days and released hPDLSCs, with 5-fold increase of proliferation (p＜0.05). The ALP activity and mineral synthesis of hPDLSCs were increased by Met delivery (p＜0.05). Among all groups, CPC+hPDLSCs+ 0.1%Met showed the greatest cell mineralization and osteogenesis, which were 1.5–10 folds those without Met (p＜0.05). Compared to CPC control, CPC+hPDLSCs+ 0.1%Met enhanced bone regeneration in rats by 9 folds, and increased vascularization by 3 folds (p＜0.05).</p></div><div><h3>Conclusions</h3><p>The novel injectable construct with hPDLSC and Met encapsulation demonstrated excellent efficacy for bone regeneration and vascularization in vivo in an animal model. CPC+hPDLSCs+ 0.1%Met is highly promising for dental and craniofacial applications.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 10","pages":"Pages 872-885"},"PeriodicalIF":5.0,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"7183348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of silica surface modification with silane and poly(ethylene glycol) on flexural strength, protein-repellent, and antibacterial properties of acrylic dental nanocomposites","authors":"Marzieh Kazemi ,&nbsp;Amir H. Navarchian ,&nbsp;Fatemeh Ahangaran","doi":"10.1016/j.dental.2023.07.010","DOIUrl":"https://doi.org/10.1016/j.dental.2023.07.010","url":null,"abstract":"<div><h3>Objective</h3><p>The main aim of the current work was to develop dental acrylic-based composites with protein-repellent and antibacterial properties by using surface-modified silica nanoparticles. The effects of surface modification of silica nanoparticles in protein-repellent and antibacterial activity and mechanical properties of dental composites including flexural strength, flexural modulus, and hardness were discussed.</p></div><div><h3>Methods</h3><p>The surface of silica nanoparticles was first chemically treated with 3-methacryloxypropyltrimethoxysilane (MPS) as a coupling agent and then with poly(ethylene glycol) (PEG) bonded to MPS. Dental acrylic-based composites were prepared with mass fractions of 10, 15, 20, 30, and 40 % of PEG-modified MPS-silica nanoparticles (PMS). The chemical surface modification of silica nanoparticles with MPS and PEG was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA).</p></div><div><h3>Results</h3><p>The dental composite containing 20 wt% PMS nanoparticles could reduce the protein adsorption by 28 % as compared with a composite containing 20 wt% MPS-modified silica. The antibacterial test indicated that the PMS nanoparticles can significantly reduce the adhesion of <em>Streptococcus mutans</em> and the biofilm formation on the surface of dental composites. It was found that the flexural strength increased by increasing the PMS nanoparticles from 0 to 20 wt% and then decreased by the incorporation of higher percentages of these nanoparticles. Also, with increasing the weight percentage of PMS nanoparticles, the elastic and the flexural modulus and the hardness of resin nanocomposites were increased.</p></div><div><h3>Significance</h3><p>In the current work, for the first time, dental resin composites containing PEG were prepared with excellent protein-repellent and antibacterial properties.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 10","pages":"Pages 863-871"},"PeriodicalIF":5.0,"publicationDate":"2023-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"7183365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication and characterization of a novel injectable human amniotic membrane hydrogel for dentin-pulp complex regeneration","authors":"Hengameh Bakhtiar ,&nbsp;Mohammad Reza Mousavi ,&nbsp;Sarah Rajabi ,&nbsp;Mohammad Pezeshki-Modaress ,&nbsp;Alireza Ayati ,&nbsp;Azin Ashoori ,&nbsp;Mohammad Reza Ellini ,&nbsp;Khadijeh Baaji ,&nbsp;Amir Kamali ,&nbsp;Zhila Abediasl ,&nbsp;Amir Azarpazhooh ,&nbsp;Anil Kishen","doi":"10.1016/j.dental.2023.06.008","DOIUrl":"https://doi.org/10.1016/j.dental.2023.06.008","url":null,"abstract":"<div><h3>Objective</h3><p>Injectable biomaterials that can completely fill the root canals and provide an appropriate environment will have potential application for pulp regeneration in endodontics. This study aimed to fabricate and characterize a novel injectable human amniotic membrane (HAM) hydrogel scaffold crosslinked with genipin, enabling the proliferation of Dental Pulp Stem Cells (DPSCs) and optimizing pulp regeneration.</p></div><div><h3>Methods</h3><p>HAM extracellular matrix (ECM) hydrogels (15, 22.5, and 30 mg/ml) crosslinked with different genipin concentrations (0, 0.1, 0.5, 1, 5, and 10 mM) were evaluated for mechanical properties, tooth discoloration, cell viability, and proliferation of DPSCs. The hydrogels were subcutaneously injected in rats to assess their immunogenicity. The hydrogels were applied in a root canal model and subcutaneously implanted in rats to determine their regenerative potential for eight weeks, and histological and immunostaining analyses were performed.</p></div><div><h3>Results</h3><p>Hydrogels crosslinked with low genipin concentration demonstrated low tooth discoloration, but 0.1 mM genipin crosslinked hydrogels were excluded due to their unfavourable mechanical properties. The degradation ratio was lower in hydrogels crosslinked with 0.5 mM genipin. The 30 mg/ml-0.5 mM crosslinked hydrogel exhibited a microporous structure, and the modulus of elasticity was 1200 PA. <em>In vitro,</em> cell culture showed maximum viability and proliferation in 30 mg/ml-0.5 mM crosslinked hydrogel. All groups elicited minimum immunological responses, and highly vascularized pulp-like tissue was formed in human tooth roots in both groups with/without DPSCs.</p></div><div><h3>Significance</h3><p>Genipin crosslinking improved the biodegradability of injectable HAM hydrogels and conferred higher biocompatibility. Hydrogels encapsulated with DPSCs can support stem cell viability and proliferation. In addition, highly vascularized pulp-like tissue formation by this biomaterial displayed potential for pulp regeneration.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 8","pages":"Pages 718-728"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2308163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-performance photoinitiating systems for new generation dental fillings","authors":"Monika Topa-Skwarczyńska ,&nbsp;Magdalena Jankowska ,&nbsp;Alicja Gruchała-Hałat ,&nbsp;Filip Petko ,&nbsp;Mariusz Galek ,&nbsp;Joanna Ortyl","doi":"10.1016/j.dental.2023.06.003","DOIUrl":"https://doi.org/10.1016/j.dental.2023.06.003","url":null,"abstract":"<div><h3>Objectives</h3><p>To obtain new generation dental composites with improved performance properties compared to currently available dental fillings on the market and to determine the influence of new initiating systems on final product parameters such as degree of cure, hardness, color, and shrinkage.</p></div><div><h3>Methods</h3><p>In order to verify the effectiveness of the developed initiating systems, typical spectroscopic, electrochemical, and kinetic studies using the real-time FT-IR method were shown. Moreover, paste dental fillings were prepared, the compositions were irradiated with the dental lamp, and the degrees of cross-linking were measured by Raman spectroscopy. The polymerization shrinkage was also determined using the rheometer. In addition, their hardness was examined on the Shore scale. Finally, the color analysis of the composites in the L*a*b* color space was compared with the VITA CLASSIC colorant.</p></div><div><h3>Results</h3><p>It was shown that, due to their excellent spectroscopic and electrochemical properties, new quinazolin-2-one can act as co-initiators in cationic and radical photopolymerization. It was demonstrated that the most effective composite containing the initiator system in the form of 3-SCH₃Ph-Q, IOD, MDEA, and an inorganic filler as nanometric silica and a bonding agent is cured more than 90% after just 1 cycle of dental lamp exposure (30 s), the hardness of the composite after curing on the Shor Scale is 82 ± 4, and the polymerization shrinkage is less than 2.8%.</p></div><div><h3>Significance</h3><p>The article demonstrates effective new initiator systems as an alternative to CQ/amine for obtaining new-generation dental composites. The developed dental composites are a big competition to the currently used dental fillings on the market.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 8","pages":"Pages 729-742"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3460402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical properties and bonding of maxillofacial silicone elastomer mixed with nano-sized anti-microbials","authors":"Muhanad M. Hatamleh ,&nbsp;Ayman M. Maqableh ,&nbsp;Ahed Al-Wahadni ,&nbsp;Mohammad A. Al-Rabab’ah","doi":"10.1016/j.dental.2023.05.009","DOIUrl":"https://doi.org/10.1016/j.dental.2023.05.009","url":null,"abstract":"<div><h3>Objectives</h3><p>The antibacterial efficacy of silicone is improved by impregnating it with antimicrobials such as chlorohexidine and zinc oxide. The purpose of this study was to examine mechanical properties and bonding of maxillofacial silicone elastomer mixed with Zinc Oxide nanoparticles (ZnO-NP), and Chlorohexidine Diacetate Salt (CHX) at three different concentrations (1 %, 3 %, and 5 %).</p></div><div><h3>Methods</h3><p>Specimens of a silicone elastomer (M511) were prepared and divided into 7 groups. Group 1 was control of no additive. Groups 2–4 included silicone elastomer mixed with ZnO-NP (surface area = 67 m²/g) at 3 different concentrations (by weight %); 1 %, 3 % and 5 %. Groups 5–7 included silicone elastomer mixed with CHX at the same concentrations. Tear and tensile strengths, elongation percentage, modulus of elasticity, and shear bond strength to primed acrylic resin surfaces were evaluated. Data was analyzed with 1-way ANOVA, Bonferroni, and Dunnett’s T3 post-hoc tests (P &lt; 0.05).</p></div><div><h3>Results</h3><p>There was significant effect of the additives on the tensile strength, elongation percentage, tear strength, and shear bond strength (P &lt; 0.05). Shear bond strengths ranged from 0.55 to 0.96 MPa. Silicone elastomer mixed with CHX (5 %) resulted in the highest shear bond strength (P &lt; 0.05). Non-linear regressions between tensile strength and ZnO and CHX additives were 0.95 and 0.96 respectively.</p></div><div><h3>Significance</h3><p>All additives reduced the tensile strength of the silicone. However, CHX at 5 % optimized shear bond strength and thus is proposed in order to fabricate maxillofacial prostheses of sufficient mechanical properties, bonding and antimicrobial activity.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 8","pages":"Pages 677-681"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3460400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The science and mechanics of adhesion: An industrial view","authors":"Afshin Falsafi","doi":"10.1016/j.dental.2023.06.001","DOIUrl":"https://doi.org/10.1016/j.dental.2023.06.001","url":null,"abstract":"<div><h3>Objectives</h3><p>Undoubtedly, adhesion is one of the broadest terms in science and technology used to describe several bulk and interface related phenomena. While the thermodynamic work of adhesion is determined by contacting surfaces and their intrinsic surface energetics, it is important to understand how adhesive properties of materials are additionally governed and amplified by their dissipative rate processes in the bulk or near the interface as they go through large strains and deformation.</p></div><div><h3>Methods</h3><p>Systematic review of the literature showed that the involved interfacial mechanisms were grouped into several categories ranging from micromechanical interlocking to molecular interdiffusion of surface constituents, a characteristic of most polymeric systems.</p></div><div><h3>Results</h3><p>This paper addressed the static and dynamic contributions to the adhesion energy and discussed its relation to microstructure and surface architecture in pressure sensitive and fracture in structural adhesives. While the focus was on industrial view of adhesion, parallels in adhesive dentistry were given where connections between adhesion, boundary geometry/compliance, shrinkage stress, material model, joint design, retention, and interfacial curing were made.</p></div><div><h3>Conclusions</h3><p>Adhesion science and mechanics are complex multi-disciplinary fields involving surfaces, substrates, and loading system involving a broad range of mechanisms applicable to dentistry.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 8","pages":"Pages 682-685"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2823076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of shading on zirconia's phase transformation and flexural strength after artificial aging","authors":"Sebastian Wille,&nbsp;Rüdiger Möller,&nbsp;Matthias Kern","doi":"10.1016/j.dental.2023.06.005","DOIUrl":"https://doi.org/10.1016/j.dental.2023.06.005","url":null,"abstract":"<div><h3>Objectives</h3><p>The aim of this study was to determine the phase transformation and the influence of aging on the flexural strength of different colored zirconia. The effect of hydrothermal aging in an autoclave was compared with the effect of mechanical stress by simulating chewing.</p></div><div><h3>Methods</h3><p>High-strength zirconia (3Y-TZP) was investigated in three different colors: uncolored, A3, and D3. Disc-shaped specimens (N = 3) were analyzed by X-ray diffraction (XRD), and flexural strength was determined on bar-shaped specimens (N = 15) in a 4-point bending test before and after performing two different aging protocols: aging in an autoclave (134 °C, 70 h) and aging in a chewing simulator (5 kg load, 1.2 million cycles). During autoclave aging, the fraction of monoclinic phase on the surface was determined every 5 h. Once this exceeded 25 vol%, aging of the bar specimens was stopped.</p></div><div><h3>Results</h3><p>While in the unstained group the mean value of the proportion of monoclinic phase already exceeded 25 vol% after 30 h in the autoclave, this was the case in both stained groups only after 70 h. No measurable phase transformation could be detected after chewing simulation. Only color A3 showed a statistically significant (p ≤ 0.05) decrease in flexural strength after aging in the chewing simulator.</p></div><div><h3>Significance</h3><p>The colored zirconia showed a higher resistance to phase transformation through hydrothermal aging. The metal oxides in the staining solutions are assumed to hinder the phase transformation in the zirconia. Therefore, the significant reduction in the stained zirconia after chewing simulation is particularly interesting</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"39 8","pages":"Pages 702-707"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2308162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}