Dental Materials最新文献

{"title":"Load-bearing capacity, internal accuracy and time-efficiency of heat-pressed, milled and 3D-printed lithium disilicate ultra-thin occlusal veneers","authors":"Pune Nina Paqué ,&nbsp;Cindy Gantner ,&nbsp;Kiren Jan Mätzener ,&nbsp;Mutlu Özcan ,&nbsp;Alexis Ioannidis","doi":"10.1016/j.dental.2024.07.017","DOIUrl":"10.1016/j.dental.2024.07.017","url":null,"abstract":"<div><h3>Objectives</h3><p>The primary aim of this in vitro study was to compare the load-bearing capacity of lithium disilicate occlusal veneers, fabricated via different manufacturing processes. Secondary objectives included assessing internal accuracy and production time-efficiency.</p></div><div><h3>Methods</h3><p>Four fabrication methods for ultra-thin lithium disilicate occlusal veneers on extracted human molars with simulated erosive defects were compared (n = 20/group): CAM: milled lithium disilicate (IPS e.max CAD); HPR: heat-pressed lithium disilicate (IPS e.max Press) out of a milled PMMA template (Ddpmma CAST); 3DP: 3D-printed lithium disilicate (experimental lithium disilicate); PTE: heat-pressed lithium disilicate (IPS e.max Press) out of a 3D-printed template (SilaPrint cast). Internal accuracy was measured prior to thermo-mechanical aging, followed by static loading to measure the load-bearing capacity (F_max). Fabrication time (time-efficiency) was also recorded. Statistical analysis was performed using the Kruskal-Wallis (KW) test.</p></div><div><h3>Results</h3><p>No statistically significant differences were found in median load-bearing capacities (F_max) between the groups (KW p = 0.5902): CAM 1821 N, HPR 1896 N, 3DP 2003 N, PTE 1687 N. Significant differences were found in internal accuracy between the groups that employed printing processes (3DP, PTE) and all other groups in margins (p &lt; 0.001), cusps (p &lt; 0.0018), and fossae (p &lt; 0.0346). The time-efficiency measurements indicated an increase in fabrication time, starting from CAM 67.2 ± 5.8 min, followed by HPR 200.8 ± 33.0 min, PTE 289.2 ± 38.7 min, and peaking with the highest duration observed for 3DP 701.6 ± 8.1 min.</p></div><div><h3>Significance</h3><p>The fabrication method of ultra-thin lithium disilicate occlusal veneers does not significantly impact their load-bearing capacity, but affects the clinical fit and adaptation of the veneers.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1602-1610"},"PeriodicalIF":4.6,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0109564124002070/pdfft?md5=d549af4f732ce30a8b602828f9e3f13a&pid=1-s2.0-S0109564124002070-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141854380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigating lipopolysaccharide-induced impairment in human dental pulp stem cells with tideglusib-doped nanoparticles: Enhancing osteogenic differentiation and mineralization","authors":"Raquel Osorio ,&nbsp;Francisco J. Rodríguez-Lozano ,&nbsp;Manuel Toledano ,&nbsp;Manuel Toledano-Osorio ,&nbsp;David García-Bernal ,&nbsp;Laura Murcia ,&nbsp;Sergio López-García","doi":"10.1016/j.dental.2024.07.012","DOIUrl":"10.1016/j.dental.2024.07.012","url":null,"abstract":"<div><h3>Objective</h3><p>Drug-loaded non-resorbable polymeric nanoparticles (NPs) are proposed as an adjunctive treatment for pulp regenerative strategies. The present in vitro investigation aimed to evaluate the effectiveness of tideglusib-doped nanoparticles (TDg-NPs) in mitigating the adverse effects of bacterial lipopolysaccharide endotoxin (LPS) on the viability, morphology, migration, differentiation and mineralization potential of human dental pulp stem cells (hDPSCs).</p></div><div><h3>Methods</h3><p>Cell viability, proliferation, and differentiation were assessed using a MTT assay, cell migration evaluation, cell cytoskeleton staining analysis, Alizarin Red S staining and expression of the odontogenic related genes by a real-time quantitative polymerase chain reaction (RT-qPCR) were also performed. Cells were tested both with and without stimulation with LPS at various time points. One-way ANOVA and Tukey's test were employed for statistical analysis (<em>p</em> &lt; 0.05).</p></div><div><h3>Results</h3><p>Adequate cell viability was encountered in all groups and at every tested time point (24, 48, 72 and 168 h), without differences among the groups (<em>p</em> &gt; 0.05). The analysis of cell cytoskeleton showed nuclear alteration in cultures with undoped NPs after LPS stimulation. These cells exhibited an in blue diffuse and multifocal appearance. Some nuclei looked fragmented and condensed. hDPSCs after LPS stimulation but in the presence of TDg-NPs exhibited less nuclei changes. LPS induced down-regulation of Alkaline phosphatase, Osteonectin and Collagen1 gene markers, after 21d. LPS half-reduced the cells production of calcium deposits in all groups (<em>p</em> &lt; 0.05), except in the group with TDg-NPs (decrease about 10 %).</p></div><div><h3>Significance</h3><p>LPS induced lower mineral deposition and cytoskeletal disorganization in hDPSCs. These effects were counteracted by TDg-NPs, enhancing osteogenic differentiation and mineralization.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1591-1601"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786670","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 crown accuracy of additively manufactured zirconia restorations","authors":"Sae-Eun Oh ,&nbsp;Ji-Man Park ,&nbsp;Jee-Hwan Kim ,&nbsp;June-Sung Shim ,&nbsp;Young-Bum Park","doi":"10.1016/j.dental.2024.07.016","DOIUrl":"10.1016/j.dental.2024.07.016","url":null,"abstract":"<div><h3>Objectives</h3><p>We evaluated the mechanical properties of zirconia restorations produced via additive manufacturing (AM) and the crown accuracy of zirconia crowns.</p></div><div><h3>Methods</h3><p>Zirconia disks, bars, and crowns were manufactured via subtractive (CNC group) and additive manufacturing (AM group) techniques. Disk-shaped specimens in each group were autoclaved at 134 °C and 216 kPa for 5, 10, and 24 h. The phases of the specimens were analyzed using an X-ray diffractometer. The flexural strengths were measured via biaxial flexural tests. The morphologies were examined using a scanning electron microscope. The correlation between the m-phase fraction and biaxial flexural strength by autoclave time in each group was analyzed via linear mixed model and Pearson’s correlation analysis. For each group, crown specimens were used to assess the marginal and internal gaps using the replica technique. Buccolingual and mesiodistal cross-sections were measured, and a repeated measures one-way ANOVA was performed.</p></div><div><h3>Results</h3><p>Linear mixed model analysis indicated that for both groups, with an increase in the autoclave time, the flexural strength decreased, whereas the m-phase fraction increased. Pearson’s correlation analysis revealed no correlation between the m-phase fraction and flexural strength for either group. A repeated measures one-way ANOVA was conducted on instrumented sections (buccal, lingual, mesial, and distal), revealing that the marginal and internal gaps of AM-produced zirconia crowns were less accurate than those of CNC-produced zirconia crowns.</p></div><div><h3>Significance</h3><p>These findings suggest that additively produced zirconia restorations have mechanical properties comparable to those of conventionally produced ceramics and may be suitable for clinical applications.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1546-1556"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764599","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":"Enhancing biofilm resistance and preserving optical translucency of 3D printed clear aligners through carboxybetaine-copolymer surface treatment","authors":"Chengzan Wu ,&nbsp;Utkarsh Mangal ,&nbsp;Ji-Young Seo ,&nbsp;Hoon Kim ,&nbsp;Na Bai ,&nbsp;Jung-Yul Cha ,&nbsp;Kee-Joon Lee ,&nbsp;Jae-Sung Kwon ,&nbsp;Sung-Hwan Choi","doi":"10.1016/j.dental.2024.07.009","DOIUrl":"10.1016/j.dental.2024.07.009","url":null,"abstract":"<div><h3>Objectives</h3><p>This study aimed to use a carboxybetaine methacrylate (CBMA) copolymer solution to surface treat 3D printed clear aligners at different fabrication stages, to impart antifouling properties, and assess the surface treatment at various fabrication stages' impact on physico-mechanical characteristics.</p></div><div><h3>Methods</h3><p>Surface treatments using a blend of 2-hydroxyethyl methacrylate (HEMA) and CBMA, termed CCS, were performed at various stages of 3D printed clear aligner fabrication. Experimental groups, CB1, CB2, and CB3, were determined by the stage of surface treatment during post-processing. CB1, CB2, and CB3 received treatment before post-curing, after post-curing, and after post-processing, respectively. Untreated samples served as controls. Physical and mechanical properties were assessed through tensile testing, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and UV-Vis spectroscopy. The surface was further characterized through scanning electron microscopy and contact angle measurements. The cytotoxicity was assessed with 7-day elution and agar diffusion assays. Lastly, bacterial biofilm resistance was evaluated using confocal laser scanning microscopy. Crystal violet assay was performed using <em>Streptococcus mutans</em>.</p></div><div><h3>Results</h3><p>Surface treatment during CB1 stage exerted the most significantly unfavorable influence on properties of the 3D printed aligner resin. CB2 samples showed the maximum preservation of translucency even after 7-day aging. CB2 and CB3 phases showed enhanced hydrophilicity of sample surfaces with reduced adhesion of multispecies biofilm and <em>S. mutans</em>.</p></div><div><h3>Significance</h3><p>Application of CCS surface treatment immediately after post-curing (CB2) can enhance the biofilm resistance of 3D printed clear aligners while maintaining high fidelity to optical translucency and constituent mechanical properties.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1575-1583"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786758","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":"Novel antibacterial orthodontic elastomeric ligature with oral biofilm-regulatory ability to prevent enamel demineralization","authors":"Ce Bian ,&nbsp;Menghao Lyu ,&nbsp;Mengyao Zhu ,&nbsp;Miao Liu ,&nbsp;Xianju Xie ,&nbsp;Michael D. Weir ,&nbsp;Gary D. Hack ,&nbsp;Radi Masri ,&nbsp;Ke Zhang ,&nbsp;Yuxing Bai ,&nbsp;Hockin H.K. Xu ,&nbsp;Ning Zhang","doi":"10.1016/j.dental.2024.07.015","DOIUrl":"10.1016/j.dental.2024.07.015","url":null,"abstract":"<div><h3>Objectives</h3><p>To synthesize a novel antibacterial orthodontic elastomeric ligature incorporating dimethylaminohexadecyl methacrylate (DMAHDM) for the first time to prevent enamel demineralization during orthodontic therapy.</p></div><div><h3>Methods</h3><p>Various mass fractions of DMAHDM (ranging from 0 % to 20 %) were grafted onto commercial elastomeric ligatures using an ultraviolet photochemical grafting method and were characterized. The optimal DMAHDM concentration was determined based on biocompatibility and mechanical properties, and the antibacterial efficacy was evaluated in a whole-plaque biofilm model. TaqMan real-time polymerase chain reaction and fluorescence in situ hybridization were used to assess the microbial regulatory ability of the multispecies biofilms. Furthermore, an in vitro tooth demineralization model was established to explore its preventive effects on enamel demineralization. Statistical analysis involved a one-way analysis of variance and LSD post hoc tests at a significance level of 0.05.</p></div><div><h3>Results</h3><p>The elastomeric ligature containing 2 % mass fraction of DMAHDM exhibited excellent mechanical properties, favorable biocompatibility, and the most effective antibacterial ability against microorganisms, which decreased by almost two logarithms (P &lt; 0.05). It significantly reduced the proportion of <em>Streptococcus mutans</em> in the multispecies plaque biofilm by 25 % at 72 h, leading to an enhanced biofilm microenvironment. Moreover, the novel elastomeric ligature demonstrated an obvious preventive effect on enamel demineralization, with an elastic modulus 30 % higher and hardness 62 % higher than those of the control group within 3 months (P &lt; 0.05).</p></div><div><h3>Significance</h3><p>The integration of DMAHDM with an elastomeric ligature holds significant promise for regulating biofilms and preventing enamel demineralization in orthodontic applications.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1534-1545"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764554","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 on dentin nanomechanical properties, cell viability and dentin wettability of a novel plant-derived biomodification monomer","authors":"Mário A. Moreira ,&nbsp;Madiana M. Moreira ,&nbsp;Diego Lomonaco ,&nbsp;Eduardo Cáceres ,&nbsp;Lukasz Witek ,&nbsp;Paulo G. Coelho ,&nbsp;Emi Shimizu ,&nbsp;Angela Quispe-Salcedo ,&nbsp;Victor P. Feitosa","doi":"10.1016/j.dental.2024.07.010","DOIUrl":"10.1016/j.dental.2024.07.010","url":null,"abstract":"<div><h3>Objectives</h3><p>To evaluate the effects of dentin biomodification agents (Proanthocyanidin (PAC), Cardol (CD) and Cardol-methacrylate (CDMA) on dentin hydrophilicity by contact angle measurement, viability of dental pulp stem cells (DPSCs) and nanomechanical properties of the hybrid layer (HL).</p></div><div><h3>Methods</h3><p>CDMA monomer was synthesized from cardol through methacrylic acid esterification. Human extracted third molars were used for all experiments. For nanomechanical tests, specimens were divided in four groups according to the primer solutions (CD, CDMA, PAC and control) were applied before adhesive and composite coating. Nanomechanical properties of the HL were analyzed by nanoindentation test using a Berkovich probe in a nanoindenter. Wettability test was performed on dentin surfaces after 1 min biomodification and measured by contact angle analysis. Cytotoxicity was assessed by a MTT assay with DPSCs after 48 and 72 h. Data were analyzed with Student's t test or Two-way ANOVA and Tukey HSD test (p &lt; 0.05).</p></div><div><h3>Results</h3><p>CD and CDMA solutions achieved greater hydrophobicity and increased the water-surface contact angles when compared to PAC and control groups (p &lt; 0.05). PAC group showed a greater reduction of elastic modulus in nanoindentation experiments when compared to CD and CDMA groups (p &lt; 0.05) after 4 months of aging. CD inhibited cell proliferation compared to all further materials (p &lt; 0.05), whilst CDMA and PAC indicated no cell cytotoxicity to human DPSCs.</p></div><div><h3>Significance</h3><p>Cardol-methacrylate provided significantly higher hydrophobicity to dentin and demonstrated remarkable potential as collagen crosslinking, attaining the lowest decrease of HL’s mechanical properties. Furthermore, such monomer did not affect pulp cytotoxicity, thereby highlighting promising feasibility for clinical applications.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1584-1590"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786757","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":"Cytotoxicity and microbiological behavior of universal resin composite cements","authors":"Uros Josic ,&nbsp;Gabriella Teti ,&nbsp;Andrei Ionescu ,&nbsp;Tatjana Maravic ,&nbsp;Claudia Mazzitelli ,&nbsp;Stevan Cokic ,&nbsp;Bart Van Meerbeek ,&nbsp;Mirella Falconi ,&nbsp;Eugenio Brambilla ,&nbsp;Annalisa Mazzoni ,&nbsp;Lorenzo Breschi","doi":"10.1016/j.dental.2024.07.004","DOIUrl":"10.1016/j.dental.2024.07.004","url":null,"abstract":"<div><h3>Objectives</h3><p>To investigate the cytotoxicity on human dental pulp cells (HDPCs) and <em>Streptococcus mutans</em> (<em>S.mutans</em>) biofilm formation on universal resin composite cements (UCs).</p></div><div><h3>Methods</h3><p>Three UCs (RelyX Universal, 3 M Oral Care - RXU; Panavia SA Cement Universal, Kuraray Noritake - PSAU; SoloCem, Coltene - SCM) and one ‘gold-standard’ multi-step cement (Panavia V5, Kuraray Noritake - PV5) were used following two polymerization protocols (light-cured - LC; self-cured - SC). Cytotoxicity (MTT) tests were performed after 1, 3 and 7 days of direct contact. Carboxy-2′,7′-dichlorodihydrofluorescein diacetate was used to detect the release of reactive oxygen species (ROS), and interleukin 6 (IL-6) expression was analyzed by IL-6 proquantum high sensitivity immunoassay. <em>S. mutans</em> biofilms were grown on UCs samples in a bioreactor for 24 h, then adherent viable biomass was assessed using MTT assay. For microbiological procedures, half of UCs samples underwent accelerated aging. Data were statistically analyzed (α = 0.05).</p></div><div><h3>Results</h3><p>The highest cytotoxicity was observed for PSAU SC, RXU SC, and PV5 SC at day 1, then for SC RXU after 3 days, and SC PSAU, LC PV5 and SCM after 1-week (p &lt; 0.05). There was no increase in IL-6 expression after 1 day, while it increased depending on the group at 3 and 7 days. The highest ROS expression after 12 h was recorded for PSAU SC, PV5 SC and PV5 LC. Biofilm formation was as follows: RXU &gt; &gt; PSAU = PV5 &gt; SCM, while light-curing systematically decreased biofilm formation (≈−33 %). Aging leveled out differences between UCs and between polymerization protocols.</p></div><div><h3>Significance</h3><p>The choice of cement brand, rather than category, and polymerization protocol influence cell viability and microbiological behavior. Light-curing is beneficial for reducing the harmful pulpal effect that UCs may possess.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1515-1523"},"PeriodicalIF":4.6,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0109564124002057/pdfft?md5=9700396272eab23ea0502655d60e0fb1&pid=1-s2.0-S0109564124002057-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141756113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physicochemical characterization of experimental resin-based materials containing calcium orthophosphates or calcium silicate","authors":"Mariana C.A. Resende ,&nbsp;Handially S. Vilela ,&nbsp;Marina D.S. Chiari ,&nbsp;Rafael B. Trinca ,&nbsp;Flávia R.O. Silva ,&nbsp;Roberto R. Braga","doi":"10.1016/j.dental.2024.07.002","DOIUrl":"10.1016/j.dental.2024.07.002","url":null,"abstract":"<div><h3>Objective</h3><p><span>To evaluate experimental dimethacrylate-based materials containing calcium orthophosphates<span> or calcium silicate particles in terms of their optical, mechanical and Ca</span></span>²⁺ release behaviour.</p></div><div><h3>Methods</h3><p><span><span>Dicalcium phosphate dihydrate (DCPD), </span>hydroxyapatite<span><span> (HAp), beta-tricalcium phosphate (β-TCP) or calcium silicate<span> (CaSi) particles were added to a photocurable BisGMA/TEGDMA resin (1:1 in mols) at a 30 vol% fraction. Materials containing silanized or non-silanized barium glass particles were used as controls. Degree of conversion (DC) at the top and base of 2-mm thick specimens was determined by ATR-FTIR spectroscopy (n = 5). Translucency parameter (TP) and transmittance (%T) were determined using a spectrophotometer (n = 3). Biaxial </span></span>flexural strength<span> (BFS) and flexural modulus (FM) were determined by biaxial flexural testing after 24 h storage in water (n = 10). Ca</span></span></span>²⁺<span> release in water was determined during 28 days by inductively coupled plasma optical emission spectrometry (n = 3). Statistical analysis was performed using ANOVA/Tukey test (DC: two-way; TP, %T; BFS and FM: one-way; Ca</span>²⁺ release: repeated measures two-way, α = 5 %). <em>Results:</em> CaSi and β-TCP particles drastically reduced DC at 2 mm, TP and %T (p &lt; 0.001). Compared to both controls, all Ca²⁺-releasing materials presented lower BFS (p &lt; 0.001) and only the material with DCPD showed significantly lower FM (p &lt; 0.05). The material containing CaSi presented the highest Ca²⁺ release, while among materials formulated with calcium orthophosphates the use of DCPD resulted in the highest release (p &lt; 0.001).</p></div><div><h3>Significance</h3><p>CaSi particles allowed the highest Ca²⁺<span> release. Notwithstanding, the use of DCPD resulted in a material with the best compromise between optical behaviour, DC, strength and Ca</span>²⁺ release.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 10","pages":"Pages 1507-1514"},"PeriodicalIF":4.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141756114","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":"Novel approach for characterizing clinical load application of superelastic orthodontic wires","authors":"","doi":"10.1016/j.dental.2024.06.028","DOIUrl":"10.1016/j.dental.2024.06.028","url":null,"abstract":"<div><h3>Objective</h3><p>Current standardized in vitro bending experiments for orthodontic archwires cannot capture friction conditions and load sequencing during multi-bracket treatment. This means that clinically relevant forces exerted by superelastic wires cannot be predicted. To address these limitations, this study explored a novel test protocol that estimates clinical load range.</p></div><div><h3>Methods</h3><p>The correction of a labially displaced maxillary incisor was simulated using an in vitro model with three lingual brackets. Deflection force levels derived from four different protocols were designed to explore the impact of friction and wire load history. These force levels were compared in nickel-titanium (NiTi) archwires with three commonly used diameters. The unloading path varied between protocols, with single or multiple sequences and different load orders and initial conditions.</p></div><div><h3>Results</h3><p>Deflection forces from the new protocol, employing multiple continuous load/unload cycles (CC_incr), consistently exceeded those from the conventional protocol using a single continuous unloading path (CU_decr). Mean differences in plateau force ranged from 0.54 N (Ø 0.014\" wire) to 1.19 N (Ø 0.016\" wire). The CC_inr protocol also provided average force range estimates of 0.47 N (Ø 0.012\" wire), 0.89 N (Ø 0.014\" wire), and 1.15 N (Ø 0.016\" wire).</p></div><div><h3>Significance</h3><p>Clinical orientation towards CU_decr carries a high risk of excessive therapeutic forces because clinical loading situations caused by friction and load history are underestimated. Physiological tooth mobility using NiTi wires contributes decisively to the therapeutic load situation. Therefore, only short unloading sequences starting from the maximum deflection in the load history, as in CC_incr, are clinically meaningful.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 9","pages":"Pages 1487-1496"},"PeriodicalIF":4.6,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0109564124001854/pdfft?md5=3a76cb64a2e8dfeb6a8a19619003e960&pid=1-s2.0-S0109564124001854-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141537114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of photoinitiator type and filler load on physicochemical and mechanical properties of experimental light-cured resin cements through lithium disilicate ceramics of different shades and thicknesses","authors":"","doi":"10.1016/j.dental.2024.06.020","DOIUrl":"10.1016/j.dental.2024.06.020","url":null,"abstract":"<div><h3>Objective</h3><p><span><span><span>This study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), </span>flexural strength (FS), </span>flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of </span>lithium disilicate ceramics.</p></div><div><h3>Methods</h3><p><span>Lithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller<span> loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm</span></span>²<span> ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV–vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05).</span></p></div><div><h3>Results</h3><p><span>Thicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and </span>mechanical characteristics of the resin-based materials (p &lt; 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p &lt; 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p &lt; 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p &lt; 0.05).</p></div><div><h3>Significance</h3><p>The luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 9","pages":"Pages 1452-1463"},"PeriodicalIF":4.6,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141464815","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}