Dental Materials最新文献

{"title":"Development and characterization of photo-responsive antimicrobial resins.","authors":"Maria Luisa Leite, Sherri Sadr Karimi, Nancy Zhai, Rafael Antonio de Oliveira Ribeiro, Patricia Comeau, Edward E Putnins, Luiz Eduardo Bertassoni, Carlos Alberto de Souza Costa, Adriana Pigozzo Manso","doi":"10.1016/j.dental.2026.07.020","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.020","url":null,"abstract":"<p><strong>Objectives: </strong>This study investigated natural photosensitizers as candidates for developing photo-responsive antimicrobial dental resins. Evaluation of their physicochemical properties, followed by assessment of antimicrobial and cytotoxic effects under photodynamic therapy (PDT), was conducted.</p><p><strong>Methods: </strong>Curcumin, riboflavin, retinoic acid, and safranal were first assessed for singlet oxygen production and antimicrobial potential against Streptococcus mutans and Candida albicans under blue-light PDT (440-460 nm, 22.55 mW/cm²; 0, 20.25, 40.5, 81.0 J/cm²). Based on these results, curcumin (Cur) and/or riboflavin (B2) were incorporated into an experimental dental resin (EDR) at 0.00, 0.05, or 0.1 wt%. Physicochemical properties, including thermogravimetric analysis, degree of conversion (DC), water sorption (WS), solubility (SL), flexural strength (FS) and shear bond strength (SBS) at 24 h and 6 months. Antimicrobial efficacy against dual-species biofilms (S. mutans/C. albicans) was tested immediately and after 6 months, with or without PDT (40.5 J/cm²). Cytotoxicity was assessed using gingival epithelial cells (extract test) and odontoblast-like cells (transdentinal test), with or without PDT (40.5 J/cm²).</p><p><strong>Results: </strong>Photosensitizer-loaded EDRs showed no adverse effects on DC, WS, or SL. Improved FS after aging was observed for B2-containing formulations, while SBS remained stable except for the 0.1% Cur group. All photosensitizer-loaded EDRs exhibited long-lasting antimicrobial activity when combined with PDT. Cytotoxicity was formulation-dependent, with only the highest Cur + B2 concentration showing adverse effects when combined with PDT.</p><p><strong>Significance: </strong>These findings demonstrate the feasibility of photo-responsive dental resins for sustained, on-demand antimicrobial activity. Notably, 0.1% B2-loaded EDR combined with PDT showed optimal antimicrobial efficacy, biocompatibility, and physicochemical performance.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617773","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":"Rapid and durable dentinal tubule occlusion via ion-mediated intratubular coprecipitation.","authors":"Zhenzhen Zhang, Chang Shu, Shengli Hu, Jingheng Wu, Yadong Chen, Yanji Lu, Qi Zhong, Mengqi Pan, Jiajia Xu, Zhuo Chen, Xiaodong Li, Qiaojie Luo","doi":"10.1016/j.dental.2026.07.015","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.015","url":null,"abstract":"<p><strong>Objectives: </strong>Dentin hypersensitivity arises from fluid movement within patent dentinal tubules. Existing chemically mediated occlusion strategies require days to weeks, limiting clinical applicability. This study developed a rapid CaCl₂/AgF regimen for durable dentinal tubule occlusion.</p><p><strong>Methods: </strong>Human third molars were acid-etched with 37% phosphoric acid for 15 s to establish an exposed dentin model. Specimens were sequentially treated with 0.05 M CaCl₂ and 0.1 M AgF for 20 s each (Ca-Ag group). Gluma, Duraphat, and Actimins served as comparators. Tubule occlusion, surface hardness, resistance to abrasive, ultrasonic, and acidic challenges, and fluid transport through pulp were evaluated.</p><p><strong>Results: </strong>The Ca-Ag regimen achieved near-complete tubule occlusion (97.5 ± 1.4%) with deep intratubular deposits (96.0 ± 10.5 μm), significantly outperforming commercial desensitizers (p < 0.001). Tubule sealing remained stable after abrasive (92.2 ± 4.3%), ultrasonic (93.8 ± 2.8%), and acidic (95.2 ± 1.9%) challenges. Surface hardness increased from 34.5 ± 2.8 HV to 46.3 ± 3.7 HV. Under 15 cm H₂O pulp pressure, Ca-Ag markedly reduced fluid penetration, decreasing the mean fluorescence intensity from 173.9 ± 14.8-37.4 ± 6.5 AU (p < 0.001), whereas minimal reductions were observed in the other groups.</p><p><strong>Conclusions: </strong>CaCl₂/AgF treatment enables rapid, deep, and durable dentinal tubule occlusion with strong resistance to mechanical and chemical challenges.</p><p><strong>Significance: </strong>The Ca-Ag regimen provides a rapid and durable ex vivo dentinal tubule occluding strategy. The clinical desensitizing efficacy and long-term performance require validation through well-controlled in situ and clinical trials.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148597203","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 performance of high-impact 3D-printed denture base resins subjected to thermomechanical aging.","authors":"Abdulaziz Alhotan, Nick Silikas, Yomna M Ibrahim, Hanan Al-Johani, Mohamed Mahmoud Abdul-Monem","doi":"10.1016/j.dental.2026.07.016","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.016","url":null,"abstract":"<p><strong>Objectives: </strong>Studies on the mechanical performance of high-impact 3-dimensionally (3D)-printed denture base resins (DBRs) after thermomechanical aging are limited. This in vitro study assessed the flexural strength (FS), flexural modulus (FM), Vickers microhardness (VHN), and fractographic patterns of high-impact 3D-printed DBRs.</p><p><strong>Methods: </strong>Four 3D-printed DBRs were evaluated in conventional (Tera Harz Denture Base [TH] and Denturetec [DT]) and high-impact (Freeprint Denture Impact [FI] and Printodent GR-14.2 Denture HI | MSI [PT]) formulations (n = 80). Standardized bar-shaped specimens were designed, fabricated, polished, and subjected to thermomechanical aging (10,000 loading cycles at 5 Hz; 10,000 thermocycles between 5 °C and 55 °C). FM and FS were determined using a 3-point bending test in a universal testing machine, and VHN values were measured using a microhardness tester. Fractographic analysis was performed using a scanning electron microscopy. Measurements were obtained at baseline and after thermomechanical aging. Data were analyzed using a generalized linear model and Bonferroni corrected post hoc tests (α = 0.05).</p><p><strong>Results: </strong>Resin type, aging condition, and their interaction significantly affected FS, FM, and VHN values (p < 0.001). DT and PT exhibited significantly higher FS values than TH and FI (p ≤ 0.007). The highest FM values were observed in DT materials (p ≤ 0.004), whereas the highest VHN values were found in PT (p < 0.001). Thermomechanical aging resulted in a significant decline in all outcomes (p ≤ 0.042). Distinct fractographic differences were identified among the DBRs.</p><p><strong>Significance: </strong>All tested 3D-printed DBRs met ISO requirements for flexural strength and modulus after thermomechanical aging. However, the notable reductions in flexural and hardness outcomes among some materials suggest the importance of appropriate material selection based on clinical indication and regular monitoring during clinical service.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148589548","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 biphasic concentration-dependent effect of strontium on the mineralization of reconstituted type I collagen and demineralized dentin.","authors":"Zhiwen Liu, Danni Wang, Leiqing Zhang, Yuan Xie, Taoyu Chen, He Wen, Wenjia Chen, Baiping Fu, Ruikang Tang, Hongqiang Cheng, Zhe Wang","doi":"10.1016/j.dental.2026.07.013","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.013","url":null,"abstract":"<p><strong>Objectives: </strong>To investigate the concentration-dependent effects of strontium on the mineralization of reconstituted type I collagen and demineralized dentin remineralization.</p><p><strong>Methods: </strong>Sr²⁺ at varying concentrations (0, 0.1, 0.25, 0.5, 0.75, 1 mM) was incorporated into polyacrylic acid-stabilized amorphous calcium phosphate (PAA-ACP) mineralization solutions. The mineralization solutions with 1 mM Sr²⁺ were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Cytocompatibility was assessed using the CCK-8 assay. Reconstituted type I collagen and demineralized dentin models were employed to explore mineralization differences; high-resolution TEM (HRTEM) and selected area electron diffraction (SAED) were applied to investigate the underlying biphasic mineralization mechanism of Sr²⁺.</p><p><strong>Results: </strong>In the reconstituted type I collagen model, early crystalline mineralization was detected at 12 h in the 0.25 mM group, while 0.5 mM Sr²⁺ induced more ordered apatite crystal alignment along the collagen long axis. The observed lattice expansion (d-spacings of 0.35-0.37 nm and 0.29 nm) was consistent with the formation of Sr-containing apatite-like mineral. At ≥ 0.75 mM Sr²⁺, the minerals deposited preferentially on the fibril surface replaced intrafibrillar mineralization. In the demineralized dentin model, a consistent biphasic concentration-dependent pattern was observed: 0.1-0.5 mM Sr²⁺ was associated with increased density of the remineralized layer and enhanced dentinal tubule occlusion, the enlarged lattice spacing (d-spacings of 0.35 nm) was consistent with that observed in the reconstituted type I collagen model. In contrast, 0.75-1 mM Sr²⁺ was associated with reduced remineralization and intratubular mineral filling. Both the collagen and dentin models suggested the biphasic effect of strontium on biomimetic mineralization.</p><p><strong>Significance: </strong>Sr²⁺ shows a biphasic concentration-dependent response on collagen mineralization and dentin remineralization. These findings provide preliminary concentration-response information for the rational design of Sr-containing biomimetic materials.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148589551","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":"Advanced dual-cured resin with excellent mechanical properties, printing accuracy, and biocompatibility for the application of 3D printing denture base.","authors":"Ludan Qin, Xueye Liu, Tongtong Ma, Qiuyi Li, Chongao Zhang, Wenqing Meng, Yijiao Zhao, Jiao Wen, Junling Wu, Jianmin Han","doi":"10.1016/j.dental.2026.07.010","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.010","url":null,"abstract":"<p><strong>Objective: </strong>Although DLP-based 3D printing shows great potential for dental restorations, it is still limited by poor fracture toughness and excessive shrinkage of denture base resins. Herein, a novel dual-cured resin formulation was proposed to address these issues.</p><p><strong>Methods: </strong>The dual-cured liquid resins were prepared by blending photocurable acrylate (A) and thermally curable epoxy (E) resin at special ratios. Initially, the curing process was monitored, and the physical properties of the resin formulations were examined. Then, the mechanical properties were comprehensively investigated with particular emphasis on their correlation with phase distribution. Dimensional stability, printing accuracy, and biocompatibility were further measured.</p><p><strong>Results: </strong>The hybrid resins exhibited satisfactory curing efficiency, reduced volume shrinkage, and proper wettability. Specifically, compared with the pure acrylate resin, the fracture toughness of maximum stress intensity factor and total fracture work of the A6E4 (mass A: mass E = 6:4) improved by approximately 279% and 59%, respectively. Further investigation of phase distribution revealed an interpenetrating network (IPN) that prolonged the crack propagation path and contributed to the brittle-to-ductile transition of the dual-cured resin. Moreover, the application feasibility of the hybrid resin was proven by the excellent printing accuracy and biosafety.</p><p><strong>Significance: </strong>This research verified the feasibility of a dual-cured system for DLP printing denture bases, providing an advanced solution for addressing brittleness and polymerization shrinkage in 3D printing denture base materials.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148589460","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":"In situ formation of amorphous cupric phosphate for improved dentin bonding.","authors":"Yixiang Pan, Jiajia Xu, Xue Cai, Xiaodong Li, Qiaojie Luo, Xiaoyan Wang","doi":"10.1016/j.dental.2026.07.014","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.014","url":null,"abstract":"<p><strong>Objective: </strong>Insufficient penetration of bonding agents into the demineralized dentin matrix (DDM) leads to a poor-quality hybrid layer and reduced bonding durability. We designed a pretreatment agent consisting of copper sulfate and dipotassium hydrogen phosphate to form amorphous copper phosphate nanoparticles (Nano-ACuP) in situ for improved dentin bonding.</p><p><strong>Methods: </strong>The effect of different concentrations of the pretreatment agent on the release of confined water was investigated. Moreover, the deposition and binding sites, hydrophilicity, surface charge, and mechanical properties were characterized. The effect of Nano-ACuP pretreatment on bonding durability was evaluated using microtensile strength tests and nano-permeability experiments. The collagenase inhibitory and antibacterial properties of Nano-ACuP were evaluated with a series of inhibition experiments and in situ enzyme profiling, respectively.</p><p><strong>Results: </strong>Nano-ACuP generated in situ formed chemical bonds with the polar and anionic groups of collagen and non-collagenous proteins in the DDM. Moreover, Nano-ACuP pretreatment reduced dentin interfacial hydration, decreased the dentin surface potential, increased the dentin mechanical properties, and increased the Young's modulus and hardness of the dentin matrix. Nano-ACuP pretreatment promoted the penetration of bonding monomers into the hybrid layer. When Nano-ACuP was used in combination with Single Bond 2 or Single Bond Universal, it improved the bonding strength and durability, which was minimally reduced over 1 year of water aging. Nano-ACuP inhibited collagenase activity and possessed antimicrobial properties.</p><p><strong>Significance: </strong>Nano-ACuP pretreatment significantly improved the effectiveness and durability of dentin bonding by reconfiguring the interfacial microenvironment of DDM. This study provides new ideas and strategies for further improving dentin bonding.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148589441","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":"Design of Experiments (DOE) approach for multi-response optimization of experimental self-adhesive flowable resin composites.","authors":"Miguel Alves, Clara Alves, Diana C Silva, António Hs Delgado","doi":"10.1016/j.dental.2026.07.012","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.012","url":null,"abstract":"<p><strong>Objectives: </strong>To determine how functional monomer type, acidic monomer concentration and powder/liquid ratio affect the multi-response performance of experimental self-adhesive flowable resin composite (SAFRC) formulations, and to identify a favorable formulation window using design of experiments (DOE) modelling.</p><p><strong>Methods: </strong>Sixteen SAFRC formulations were prepared from a two-level formulation matrix varying monomer type (HEMA or 10-MDP), acidic monomer concentration (5 or 25 mol%), powder/liquid ratio (2.5 or 3.2) and filler condition. Degree of conversion at 20 and 40 s (DC20 and DC40; n = 3 per formulation/curing time), shear bond strength (SBS; n = 5 per formulation), water sorption/solubility and rheology were measured. Because rheological geometry was linked to formulation consistency, lower-viscosity cone-plate (CP) and higher-viscosity parallel-plate (PP) subsets were analyzed separately. Factorial models were fitted for each response, followed by desirability-based multi-response optimization.</p><p><strong>Results: </strong>No formulation simultaneously optimized all responses. HEMA-containing formulations generally showed higher DC20/DC40, whereas 10-MDP-containing formulations favored SBS and lower calculated solubility. In the CP subset, SBS was mainly governed by monomer chemistry and acidic monomer concentration, while DC40 was dominated by monomer type. Sorption was mainly influenced by powder/liquid ratio, and solubility showed the strongest factorial dependence. In the PP subset, DC40 and rheology remained interpretable, whereas SBS, sorption and solubility were not reliably described by the factorial models. CP optimization predicted the best compromise at 10-MDP, 25 mol% and P/L 2.72, with composite desirability of 0.509.</p><p><strong>Significance: </strong>DOE-based multi-response modelling revealed how SAFRC formulation variables redistribute performance across bonding, polymerization, handling and hydrolytic responses. This approach identified a rational formulation window for experimental SAFRC development and provides a framework for optimizing self-adhesive restorative materials beyond single-property screening.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148547332","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":"Dual-antimicrobial and remineralizing polymer fluoride for dental care.","authors":"Claire Minchun Huang, Iris Xiaoxue Yin, John Yun Niu, Ollie Yiru Yu, Chun Hung Chu","doi":"10.1016/j.dental.2026.07.011","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.011","url":null,"abstract":"<p><strong>Objective: </strong>The objective of this laboratory study is to develop an antimicrobial and mineralizing polymer fluoride.</p><p><strong>Methods: </strong>Poly (diallyldimethyl) ammonium fluoride (PDDAF) was synthesized by substitution reaction between poly (diallyldimethyl) ammonium chloride and silver fluoride. Its chemical structure was evaluated using fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDS) and 19 F nuclear magnetic resonance (NMR). The cytotoxicity of PDDAF was evaluated by Cell Counting Kit-8 assay. The minimal inhibitory concentration (MIC) and minimal bactericidal/ fungicidal concentration (MBC/ MFC) of PDDAF against S. mutans, P. gingivalis, E. faecalis and C. albicans were assessed, and microbial morphology was observed under transmission electron microscopy (TEM). Inhibition of S. mutans biofilm formation was tested by scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) The surface morphology and elemental composition of demineralized dentin treated with 30% PDDAF (30,000 ppm fluoride) were analyzed using SEM and EDS. The chemical structure and crystal characteristics were analyzed using FTIR and X-ray diffraction (XRD). Samples treated with water or 5% sodium fluoride solution (NaF, 22,600 ppm fluoride) served as controls.</p><p><strong>Results: </strong>EDS, FTIR and 19 F NMR confirmed the successful synthesis of PDDAF. PDDAF demonstrated IC50 values of 45 ± 5 ppm (human gingival fibroblasts), 133 ± 7 ppm (human dental pulp cells), and 1224 ± 429 ppm (deciduous teeth stem cells), with MICs of 41, 13, 117, and 15 ppm against S. mutans, P. gingivalis, E. faecalis, and C. albicans, respectively. TEM revealed bacterial membrane disruption at MBC/ MFC levels. SEM and CLSM showed anti-biofilm ability of PDDAF. Under SEM, PDDAF promoted dentin remineralization and occluded dentinal tubules. PDDAF-treated group exhibited greater calcium content (42.0 ± 0.7 vs. 34.2 ± 1.7; p < 0.001) and higher Ca/P ratio (1.72 ± 0.04 vs. 1.64 ± 0.04; p < 0.001) than water group. FTIR and XRD showed PDDAF-treated group had more hydroxyapatite formation and less collagen exposure than NaF-treated and water-treated groups.</p><p><strong>Conclusions: </strong>PDDAF exhibits antimicrobial and remineralizing properties.</p><p><strong>Clinical significance: </strong>PDDAF's dual antimicrobial-remineralizing action offers a novel strategy to combat oral pathogens and remineralize dentin, advancing preventive and minimally invasive restorative dental care.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148534796","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":"Kinetics of polymerization shrinkage and shrinkage stress in a self-cured resin composite.","authors":"Jing Fu, Abdulaziz Alayed, Qi Xue, Nikolaos Silikas, David C Watts","doi":"10.1016/j.dental.2026.07.007","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.007","url":null,"abstract":"<p><strong>Objectives: </strong>To characterize the polymerization shrinkage strain, shrinkage stress, and Martens hardness kinetics of a self-cured bulk-fill resin composite (STELA Automix) under different bonding protocols, and to compare its behavior with two light-cured bulk-fill composites.</p><p><strong>Methods: </strong>STELA Automix was evaluated either alone (ST_A) or with its dedicated STELA Primer (ST_A+P_ST), Adhese Universal (ST_A+AU), or Adhese Universal followed by light curing (STA+AU+LCU). Polymerization shrinkage strain (bonded-disk, 60 min, n = 3), shrinkage stress (Bioman II analyzer, 3600 s, n = 3), and Martens hardness (up to 7 days, n = 5) were measured for STELA and two light-cured bulk-fill composites, Filtek One Bulk Fill and SureFil SDR flow (SDR), under equivalent conditions (23 °C). Data were analyzed by one-way ANOVA and Tukey's test (α = 0.05).</p><p><strong>Results: </strong>All STELA configurations showed higher final shrinkage strain than the light-cured bulk-fill materials (p < 0.05). Final shrinkage stresses ranged from 1.34 to 2.39 MPa, with ST_A + AU yielding the lowest and ST_A + AU + LCU the highest values (p < 0.05). The dedicated STELA Primer advanced shrinkage onset and increased the interval between onset and the maximum shrinkage-strain rate (Δt), indicating an altered early shrinkage-kinetic profile in the bonded configuration. Across the STELA protocols, shrinkage-rate development extended over tens of seconds, while Martens hardness increased gradually over 7 days and ultimately exceeded that of SDR.</p><p><strong>Significance: </strong>Despite higher polymerization shrinkage strain than the light-cured composites, STELA exhibited slower stress build-up and a prolonged viscoelastic response during early polymerization. The dedicated primer altered the early shrinkage-kinetic profile by increasing Δt, whereas additional light activation compressed this interval. This kinetic profile, which can be modified by formulation and bonding protocol, may be as critical as shrinkage magnitude in shaping interfacial stress development in bulk-fill composites.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148467992","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":"Enhanced mechanical performance of additively manufactured lithium disilicate glass-ceramics through β-spodumene/lithium metasilicate co-addition for dental applications.","authors":"Xin Zhou, Zengqi Ye, Xian Tong, Zhaoping Chen, Jiancheng Yu, Yuncang Li, Li Zhu, Cuie Wen, Jixing Lin, Jianfeng Ma","doi":"10.1016/j.dental.2026.07.006","DOIUrl":"https://doi.org/10.1016/j.dental.2026.07.006","url":null,"abstract":"<p><strong>Objectives: </strong>This study aims to improve the densification and strength of additively manufactured lithium disilicate glass-ceramics (LDGCs) for dental restorations by introducing a β-spodumene-lithium metasilicate (LM)-amorphous silicon dioxide (A-SiO₂)-glass system.</p><p><strong>Methods: </strong>Precursor slurries with varying ratios of β-spodumene, LM, and A-SiO₂ were shaped using digital light processing and subsequently sintered without applied pressure. The resulting LDGC samples were systematically evaluated in terms of density, porosity, phase composition, microstructure, mechanical properties, fracture morphology, and molding accuracy.</p><p><strong>Results: </strong>The combined addition of β-spodumene and LM significantly reduced porosity, promoted densification and crystallinity, and produced a uniform interlocked microstructure. In contrast, the introduction of A-SiO₂ facilitated the transformation of LM into lithium disilicate, but increased porosity and defects by impeding densification. The optimized β-spodumene/LM/glass ternary system achieved a maximum flexural strength of ∼332.5 MPa and a fracture toughness of ∼2.3 MPa·m^1/2, while exhibiting hardness and elastic modulus comparable to natural enamel. Moreover, crown manufacturing demonstrated high molding accuracy.</p><p><strong>Significance: </strong>The synergistic addition of β-spodumene and LM effectively enhances densification and strength in additively manufactured LDGCs, establishing a promising material system for high-load aesthetic restorations.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":" ","pages":""},"PeriodicalIF":6.3,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148467980","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}