Dental Materials最新文献

{"title":"Development of TiF4-Dendrimer complex gel as an anti-demineralization agent for dentin: An in vitro study","authors":"Taraneh Estedlal ,&nbsp;Ladan Ranjbar Omrani ,&nbsp;Khosrou Abdi ,&nbsp;Niyousha Rafeie ,&nbsp;Zohreh Moradi","doi":"10.1016/j.dental.2024.11.007","DOIUrl":"10.1016/j.dental.2024.11.007","url":null,"abstract":"<div><h3>Objective</h3><div>The anti-caries effects of titanium tetrafluoride (TiF4) are well-documented, but its low pH challenges clinical application. This study evaluated PEG-citrate dendrimer as a carrier to enhance TiF4 stability and efficacy.</div></div><div><h3>Methods</h3><div>PEG-citrate dendrimer and TiF4-dendrimer gel were synthesized, and their structures confirmed using Fourier Transform Infrared Spectroscopy (FTIR), Hydrogen Nuclear Magnetic Resonance (1H NMR), and Liquid Chromatography–Mass Spectrometry (LC-MS). Thirty-six intact human teeth were prepared, randomly divided into three groups (n = 12) and subjected to pH cycling with the following treatments: titanium tetrafluoride (T), dendrimer (D), and dendrimer with TiF4 (TD). Vickers microhardness and Raman spectroscopy evaluated dentin demineralization. EDS analysis measured titanium and fluoride penetration into dentin in T and TD groups and mineral content (calcium and phosphorus) in all groups.</div></div><div><h3>Results</h3><div>The T group showed the highest microhardness loss (p &lt; 0.001), followed by D and TD groups. EDS analysis revealed no significant difference in titanium and fluoride content between the surface and subsurface in TD (p = 0.344), while T had more titanium on the surface (p &lt; 0.001). TD had higher subsurface calcium content compared to T (p = 0.008). Raman spectroscopy revealed significant changes in phosphate-to-amide and carbonate-to-amide ratios before and after pH cycling in all groups (p &lt; 0.001), with no statistical differences among the groups.</div></div><div><h3>Conclusion</h3><div>Using dendrimer as a carrier for TiF4 increased pH and enhanced TiF44 ability to limit dentin demineralization and microhardness loss.</div></div><div><h3>Clinical Relevance</h3><div>The application of the newly-developed TiF4-dendrimer gel might be an effective approach to prevent/ limit dentin demineralization and dentin caries.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 159-168"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778735","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 evolution of adhesive dentistry: From etch-and-rinse to universal bonding systems","authors":"Lorenzo Breschi ,&nbsp;Tatjana Maravic ,&nbsp;Claudia Mazzitelli ,&nbsp;Uros Josic ,&nbsp;Edoardo Mancuso ,&nbsp;Milena Cadenaro ,&nbsp;Carmem S. Pfeifer ,&nbsp;Annalisa Mazzoni","doi":"10.1016/j.dental.2024.11.011","DOIUrl":"10.1016/j.dental.2024.11.011","url":null,"abstract":"<div><h3>Objectives</h3><div>This review aimed at presenting the mechanisms and pitfalls of adhesion to enamel and dentin, advances in the materials science and in the development of strategies to improve hybrid layer (HL) longevity.</div></div><div><h3>Methods</h3><div>Search of the literature was performed on PubMed, Scopus and Web of Science with keywords related to the structure of the dental substrate, HL degradation mechanisms and strategies to contrast them.</div></div><div><h3>Results</h3><div>Albeit the advances in the dental materials’ properties, HL degradation is still a relevant and current issue in adhesive dentistry. However, adhesive materials have become more resistant and less operator sensitive, and good adhesion is currently in the hands of every practitioner. Numerous novel strategies are being developed, able to improve the resistance of adhesive resins to degradation, their ability to infiltrate and chemically bond to dentin, to remove the unbound/residual water within the HL, reinforce the dentin collagen matrix, and inhibit endogenous metalloproteinases. Many of the strategies have turned to nature in search for powerful biomodifying compounds, and for the inspiration as to mimic naturally occurring regenerative processes.</div></div><div><h3>Significance</h3><div>Extensive knowledge on the structure of the dental substrate and the complexity of adhesion to dentin has led to the development of improved formulations of dental adhesives and numerous valid strategies to improve the strength and longevity of the HL. Nevertheless, for many of them the road from bench to chairside still seems long. We encourage practitioners to know their materials well and use the strategies readily available to them.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 141-158"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778739","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":"Bonding neat hydrophobic-rich resins to etched dentin: A proof of concept","authors":"Thiago Henrique Scarabello Stape ,&nbsp;Omar Abdelaziz Ismail ,&nbsp;Marcelo Capitanio ,&nbsp;Arzu Tezvergil-Mutluay","doi":"10.1016/j.dental.2024.10.018","DOIUrl":"10.1016/j.dental.2024.10.018","url":null,"abstract":"<div><h3>Objectives</h3><div>To examine whether the effectiveness of current dentin-priming approaches requiring solvated hydrophilic resins may be replicated by modifying the infiltration dynamics of neat methacrylate-based monomers into dry-etched dentin using dimethyl sulfoxide (DMSO) pretreatments. <em>Methods:</em> H₃PO₄-etched mid-coronal dentin surfaces from human molars were air-dried for 30 s and randomly pretreated with 50 %(v/v) ethanolic DMSO for 20 or 60 s. Untreated samples and an isolated wet-bonding group served as controls. Samples were bonded with a three-step etch-and-rinse adhesive or simply with the solvent-free hydrophobic-rich resin. Restored crown segments (n = 7/group) were stored in distilled water for 24 h and sectioned for microtensile bond strength testing. Resin-dentin beams (0.8 mm²) were tested under tension until failure (0.5 mm/min) after 24 h or 2 years of storage in artificial saliva at 37 °C. Nanoleakage evaluation and hybrid layer characterization were performed by SEM. Bond strength data was examined by three-way ANOVA followed by Tukey and Dunnett’s test (α = 0.05). <em>Results:</em> Pretreatments significantly affected the ability of neat and solvated resins to bond to etched-dry dentin (<em>p</em> = 0.001). Ageing significantly lowered bond strengths depending on resin composition and DMSO-application times (<em>p</em> = 0.007). While hybridization of DMSO-treated dentin with the solvated resin produced no significant reductions in bond strengths after ageing (<em>p</em> &lt; 0.05) improving hybrid layer integrity, direct bonding of the neat hydrophobic-rich resin matched the long-term bonding performance of the “gold standard” wet-bonding protocol (<em>p</em> &gt; 0.05). <em>Significance</em>: Lowering dentin’s hydration state via DMSO-dry bonding allows direct coupling of neat methacrylate-based resins, which may contribute to developing new strategies to ultimately extend the durability of resin-dentin interfaces.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 113-121"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142610822","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":"Effect of preparation designs and CAD-CAM materials on step-stress fatigue survival of premolar partial coverage restorations: An in-vitro study with fractographic analysis","authors":"Dina M. Nasr ,&nbsp;Islam M Abdelraheem ,&nbsp;David C. Watts ,&nbsp;Nikolaos Silikas ,&nbsp;Marcia Borba ,&nbsp;Nada Alharbi ,&nbsp;Khaled Abid Althaqafi ,&nbsp;Alaaeldin Elraggal","doi":"10.1016/j.dental.2024.11.003","DOIUrl":"10.1016/j.dental.2024.11.003","url":null,"abstract":"<div><h3>Objectives</h3><div>The growing trend of minimally invasive approaches has encouraged the application of partial coverage designs in restorative dentistry. This study aimed to evaluate the cyclic fatigue performance of different CAD-CAM materials used in various partial coverage designs for premolar restorations.</div></div><div><h3>Methods</h3><div>A freshly extracted upper premolar was prepared using a high-speed handpiece to create mesio-occluso-distal (MOD) cavities with standardized dimensions. Three preparation designs were investigated: onlay, overlay, and vonlay. CAD software was used to create digital models of the restorations, which were milled into one of four CAD-CAM materials: Zr - zirconia polycrystals (4Y-PSZ); EX - lithium disilicate glass-ceramic; VS - zirconia-reinforced lithium silicate glass-ceramic; GB - nanohybrid composite. Partial coverage restorations were bonded to tooth replicas and subjected to step-stress cyclic fatigue testing using a chewing simulator device (n = 10). The number of cycles-to-failure and fatigue fracture resistance (N) were recorded and analysed with Kaplan-Meier survival statistics and Weibull analysis, respectively. Fracture surfaces were analysed using fractography.</div></div><div><h3>Results</h3><div>Zr exhibited significantly higher number of cycles-to-failure and greater characteristic fracture load (L₀) than the other materials, for onlay and overlay designs. For vonlay design, Zr, VS and EX had similar and greater number of cycles-to-failure than GB. When comparing different designs for the same material, Zr had lower number of cycles-to-failure for vonlay in comparison to onlay and overlay, while the other materials had similar values among the different designs. Weibull modulus was similar among experimental groups<strong>.</strong></div></div><div><h3>Significance</h3><div>The findings of this study emphasize the critical role of material selection and preparation design in optimizing the mechanical performance and clinical success of partial coverage restorations. 4Y-PSZ is recommended for high-stress areas due to its superior fatigue and fracture resistance. Overlay designs provide better fatigue resistance, making them more suitable for clinical scenarios requiring higher durability. Understanding the fatigue performance of different materials and designs aids in making informed decisions to enhance the longevity and success of partial coverage restorations in premolars.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 122-133"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142764958","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":"Fatigue behavior and reliability of pressed lithium disilicate ceramics compared to 5Y-TZP zirconia under different loading protocols","authors":"Ramona Buser ,&nbsp;Mustafa Borga Dönmez ,&nbsp;Moritz Hoffmann ,&nbsp;Rüdiger Hampe ,&nbsp;Bogna Stawarczyk","doi":"10.1016/j.dental.2024.11.005","DOIUrl":"10.1016/j.dental.2024.11.005","url":null,"abstract":"<div><h3>Objective</h3><div>To compare the fatigue behavior and reliability of 5 pressed lithium disilicate ceramics and a 5 mol% yttria-stabilized zirconia (5Y-TZP) when 3 dynamic loading protocols were used.</div></div><div><h3>Methods</h3><div>Bar-shaped specimens (30 × 4 × 3 mm) were fabricated from 5 pressed lithium disilicate ceramics (AMB, CEL, INI, IPS, and LIV) and a 5Y-TZP (ZR) (N = 324). Six specimens from each material were subjected to a static 4-point fracture load test, while the remaining specimens were subjected dynamic loading by increasing the starting load (30 % of the static fracture load) in every 5000 cycles by 50 N (loading protocol 1), in every 5000 cycles by 5 % (loading protocol 2) or in every 1000 cycles by 10 N (loading protocol 3) until fracture (n = 16). The fracture load, flexural strength, and number of cycles until failure were analyzed with 2-way analysis of variance and Scheffé tests. The survival rate was evaluated with Kaplan-Meier analysis and further compared with Mantel-Cox test, while the correlation between the fracture load and flexural strength was analyzed with Pearson’s correlation test (α = 0.05). Fractographic analysis was also performed.</div></div><div><h3>Results</h3><div>The interaction between the materials and the loading protocol affected the number of cycles until failure, while the material type affected fracture load and flexural strength values (<em>P</em> &lt; 0.001). ZR had the highest and LIV mostly had lower fracture load and flexural strength (<em>P</em> ≤ 0.034). A positive correlation was found between the fracture load and flexural strength (r = 0.997, <em>P</em> &lt; 0.001). For lithium disilicate ceramics, loading protocol 2 and for ZR, loading protocols 1 and 3 led to the highest number of cycles and survival rate (<em>P</em> ≤ 0.041). Regardless of the loading protocol, all lithium disilicate ceramics had a similar fragmentation pattern with single compression curls and 2-piece fractures were observed.</div></div><div><h3>Significance</h3><div>Tested materials are suitable for adhesively luted monolithic single-unit prosthesis as they had mean flexural strength values higher than 100 MPa. Measuring the fracture load with loading protocol 3 can be considered time-efficient to evaluate the fatigue behavior of pressed lithium disilicate ceramics.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 134-140"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142764961","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 systems on resin-based composite containing ZnO-nanoparticles","authors":"Abdulaziz Alayed ,&nbsp;Nikolaos Silikas ,&nbsp;David C. Watts","doi":"10.1016/j.dental.2024.12.002","DOIUrl":"10.1016/j.dental.2024.12.002","url":null,"abstract":"<div><h3>Objective</h3><div>Zinc oxide (ZnO) powder possesses antibacterial activity and although white in color, it can severely reduce the depth of cure (<strong>DoC</strong>) of resin-based composite (RBC). This study investigated the effect of unary and binary photoinitiator systems on the <strong>DoC</strong> and degree of conversion (<strong>DC</strong>) of formulated RBC containing ZnO-nanoparticles.</div></div><div><h3>Methods</h3><div>Fourteen RBCs (n = 3/group) were formulated consisting of 50 wt% mixture of monomers (Bis-GMA, TEGDMA, and UDMA) and 50 wt% fillers (inert barium glass powder and silica nanoparticles). ZnO-nanoparticles were added at 0 (control), 0.5, 1, 1.5 and 2 wt%. A unary initiator system consists of camphorquinone (CQ) 0.25, 0.5 and 1 wt% and ethyl 4-(dimethylamino)benzoate (EDMAB) 0.75 wt% or a binary initiator system consisting of diphenyliodonium hexafluorophosphate (DPI) 0.25, 0.5 and 1 wt%, CQ 0.25, 0.5 and 1 wt% and EDMAB 0.75 wt% were added to the monomer mixture. To measure the <strong>DoC</strong>, each specimen was prepared in a custom-made mold with a slot (16 x 8×2 mm) and a top cover plate, irradiated from one end (40 s), stored dry (37° C, 1 d) and measured at increasing depths using Vickers hardness (0.5 mm intervals). 1 mm thick specimens were prepared to measure <strong>DC</strong> continuously using FTIR, from zero up to 24 h post-irradiation.</div></div><div><h3>Results</h3><div>Increasing the concentrations of ZnO led to a significant reduction of <strong>DoC</strong> (p &lt; 0.05). But most of the binary initiator groups showed significantly higher <strong>DoC</strong> (p &lt; 0.05). Depth, at 80 % of max VHN, of unary initiator groups reduced from 6.8 mm (ZnO at 0 wt%) to 2.1 mm (ZnO at 2 wt%) and in binary initiator groups from 8.4 mm to 2.3 mm. Groups with lower photoinitiator concentrations (0.25 wt%) showed a significant increase in DoC compared with groups with higher concentrations (1 wt%) (p &lt; 0.05). <strong>DC</strong> after 24 h was independent of either ZnO concentration or the photoinitiator system (p &gt; 0.05). However, faster conversions were observed in binary initiator groups. The RP_max of binary groups ranged from 8.1 % to 10.1 %/s, and unary groups ranged from 5.2 % to 7.2 %/s.</div></div><div><h3>Significance</h3><div>The addition of DPI resulted in an overall increased curing depth, which was enhanced when lower concentrations of photoinitiators were used. Also, DPI resulted in faster conversions. This is desirable in designing antibacterial RBC containing ZnO.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 220-228"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142790608","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":"Preparation of dental resin composites with anti-bacterial adhesion against Streptococcus mutans using fluorinated and silicon containing dimethacrylates","authors":"Shengcan Zhang ,&nbsp;Xinlin He ,&nbsp;Fang Liu ,&nbsp;Xiangya Huang ,&nbsp;Sui Mai ,&nbsp;Jingwei He","doi":"10.1016/j.dental.2024.11.010","DOIUrl":"10.1016/j.dental.2024.11.010","url":null,"abstract":"<div><h3>Objective</h3><div>The purpose of this study was to enhance the anti-bacterial adhesion effect against Streptococcus mutans (<em>S. mutans</em>) of fluorinated dimethacrylate (DF MA) based dental resin composites (DRCs) by using silicone dimethacrylate (SMA-MEO).</div></div><div><h3>Method</h3><div>The SMA-MEO was added into mixture of DFMA and tricyclo (5.2.1.0) decanedimethanol diacrylate (SR833s) (DFMA/SR833s = 50 wt./50 wt.) with mass ratios of 10 wt% and 20 wt% to form resin matrix both with fluorinated and silicon containing dimethacrylates, and then DRCs named DS+ 10 %SMA-MEO and DS+ 20 %SMA-MEO were prepared by mixing the resin matrix with silaned BaAlSiO₂ filler particles at a mass ratio of 30 wt./70 wt. Double bond conversion, volumetric shrinkage and shrinkage stress, flexural strength and modulus, water sorption and solubility, contact angle and surface free energy, anti-bacterial adhesion effect against <em>Streptococcus mutans</em> (<em>S. mutans</em>), and cytotoxicity of prepared DRCs were investigated according to standard or referenced methods. Fluorinated dimethacrylate (DFMA) based DRC named DS and 2,2-bis[4-(2-hydroxy-3-methacryloy-loxypropyl)-phenyl]propane (Bis-GMA) based DRC named BT were used as controls.</div></div><div><h3>Results</h3><div>Adding SMA-MEO into DFMA based DRC could lead to higher double bond conversion (<em>p</em> &lt; 0.05), higher hydrophobicity (<em>p</em> &lt; 0.05), and lower surface free energy (<em>p</em> &lt; 0.05). Only DS+ 10 %SMA-MEO had better anti-bacterial adhesion effect against <em>S. mutans</em> than DS (<em>p</em> &lt; 0.05). The SMA-MEO had no influence on volumetric shrinkage, shrinkage stress, flexural modulus, water sorption and solubility of DRC (<em>p</em> &gt; 0.05), but could reduce flexural strength of dry DRC (<em>p</em> &lt; 0.05). After water immersion, SMA-MEO containing DRCs had comparable flexural strength as DS (<em>p</em> &gt; 0.05). Compared with BT, DS and SMA-MEO containing DRCs had better or comparable physicochemical properties, and lower amount of adherent <em>S. mutans</em>. All of DRCs had comparable cytotoxicity (<em>p</em> &gt; 0.05).</div></div><div><h3>Significance</h3><div>DRCs with both DFMA and SMA-MEO could have better anti-bacterial adhesion effect against <em>S. mutans</em> than DRC only with DFMA due to increased hydrophobicity and decreased Surface free energy, and the optimal mass fraction of SMA-MEO in DFMA based resin matrix was 10 wt%.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 169-178"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142764962","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":"Biofabrication – Revolutionizing the future of regenerative periodontics","authors":"Isaac J. de Souza Araújo ,&nbsp;Marco C. Bottino","doi":"10.1016/j.dental.2024.11.006","DOIUrl":"10.1016/j.dental.2024.11.006","url":null,"abstract":"<div><div>Periodontium is a compartmentalized and highly specialized tissue responsible for tooth stability. Loss of tooth attachment due to periodontitis and trauma is a complex clinical burden affecting a large parcel of the adult and elderly population worldwide, and regenerative strategies to reestablish the native conditions of the periodontium are paramount. Biofabrication of scaffolds, through various techniques and materials, for regenerative periodontics has significantly evolved in the last decades. From the basics of occlusive membranes and graft materials to the complexity of converging 3D printing and Bioprinting using image-based models, biofabrication opens many possibilities for patient-specific scaffolds that recapitulate the anatomical and physiological conditions of periodontal tissues and interfaces. Thus, this review presents fundamental concepts related to the native characteristics of the periodontal tissues, the key to designing personalized strategies, and the latest trends of biofabrication in regenerative periodontics with a critical overview of how these emerging technologies have the potential to shift the one-size-fits-all paradigm.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 179-193"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778716","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":"Effect of beam divergence on the irradiance from dental light curing units","authors":"Anubhav Gulati ,&nbsp;Soheil Ghaffari ,&nbsp;Brett Daniel MacNeil ,&nbsp;Richard Bengt Price","doi":"10.1016/j.dental.2025.01.001","DOIUrl":"10.1016/j.dental.2025.01.001","url":null,"abstract":"<div><h3>Objective</h3><div>This study measured the beam divergence angle and light output from dental light curing units (LCUs). Twenty LCUs were assessed using a laboratory-grade wide beam imager to determine the relationship between the beam divergence on the irradiance as a function of distance from the light tip.</div></div><div><h3>Methods</h3><div>The irradiance (mW/cm²) and beam divergence angles (°) at 5, and 10 mm from the tips of 18 Light-Emitting Diode (LEDs), 1 Quartz-Tungsten-Halogen (QTH), and 1 Laser diode LCU.</div></div><div><h3>Results</h3><div>There were significant differences in the power, irradiance, and emission spectra from the 20 LCUs. At 10 mm from the LCU tip, the irradiance delivered by one LCU decreased by approximately 85.7 %, whereas this decrease was as low as 5.6 % for a different LCU. There was a positive correlation between the divergence angle reported by the wide beam imager and the reduction in irradiance. The laser diode LCU had the least beam divergence and the smallest decrease in irradiance as the distance increased. In contrast, the QTH LCU with the turbo light guide had the greatest beam divergence and the greatest reduction in irradiance as the distance increased. 50 % of the LCUs tested would require exposure times longer than 20 s to deliver 10 J/cm² at the 10 mm distance.</div></div><div><h3>Significance</h3><div>The wide beam imager is a useful tool for measuring the beam divergence from LCUs and predicting the effect of distance on their irradiance. At 10 mm, some LCUs may require a fivefold increase in the exposure time to deliver the same energy they deliver at 0 mm from the tip of the LCU.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 4","pages":"Pages 432-443"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143078125","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":"Cement layer thickness and load-bearing capacity of tooth restored with lithium-disilicate glass ceramic and hybrid ceramic occlusal veneers","authors":"Topias Yli-Urpo ,&nbsp;Lippo Lassila ,&nbsp;Timo Närhi ,&nbsp;Pekka Vallittu","doi":"10.1016/j.dental.2024.11.004","DOIUrl":"10.1016/j.dental.2024.11.004","url":null,"abstract":"<div><h3>Objectives</h3><div>To evaluate the influence of cement layer and veneer thickness on load-bearing capacity of tooth restored with hybrid ceramic (HC) and lithium-disilicate glass ceramic (LDGC) occlusal veneer restorations.</div></div><div><h3>Methods</h3><div>Cement layer thickness was set at either 50 µm or 200 µm and tooth restored either with 0.5 mm or 1.8 mm thick HC Cerasmart270 (GC) or LDGC IPS e.max CAD (Ivoclar Vivadent) occlusal veneers. For this study, 64 extracted human molar teeth were selected and divided into 8 groups. Prepared teeth were scanned, and occlusal veneers were manufactured using CAD/CAM technology (Cerec, Dentsply-Sirona). Finished veneers were luted to preparations using self-adhesive resin cement (G-CEM ONE) according to manufacturers’ instructions. Teeth were loaded quasi-statically and ultimate fracture loads were recorded. Fracture types were analyzed and classified visually. Statistical analysis was performed using two-way ANOVA.</div></div><div><h3>Results</h3><div>With HC occlusal veneers, thickness of both veneer and cement layer had no significant influence on fracture load. The lowest mean ultimate fracture load value was found in 0.5 mm thick LDGC veneers group with 200 µm cement layer, which was significantly lower loading value compared with that of 1.8 mm thick LDGC veneers or any of HC veneers (p ≤ 0.0280). LDGC veneers with 0.5 mm thickness showed fractures within the veneer, whereas in other groups fractures of the tooth substance was also detected.</div></div><div><h3>Conclusions</h3><div>Within the limitations of this study, it can be concluded that thin HC occlusal veneers provided higher load-bearing capacity than LDGC counterparts of the same thickness. HC veneers were also less sensitive to the effect of cement layer thickness.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"41 2","pages":"Pages 212-219"},"PeriodicalIF":4.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142790680","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}