Dental Materials最新文献

{"title":"Emerging nanozyme therapy incorporated into dental materials for diverse oral pathologies","authors":"Menghan Zhao ,&nbsp;Jin Yang ,&nbsp;Jiangyi Liang ,&nbsp;Ruixin Shi ,&nbsp;Wei Song","doi":"10.1016/j.dental.2024.07.025","DOIUrl":"10.1016/j.dental.2024.07.025","url":null,"abstract":"<div><h3>Objective</h3><div>Nanozyme materials combine the advantages of natural enzymes and artificial catalysis, and have been widely applied in new technologies for dental materials and oral disease treatment. Based on the role of reactive oxygen species (ROS) and oxidative stress pathways in the occurrence and therapy of oral diseases, a comprehensive review was conducted on the methods and mechanisms of nanozymes and their dental materials in treating different oral diseases.</div></div><div><h3>Methods</h3><div>This review is based on literature surveys from PubMed and Web of Science databases, as well as reviews of relevant researches and publications on nanozymes in the therapy of oral diseases and oral tumors in international peer-reviewed journals.</div></div><div><h3>Results</h3><div>Given the unique function of nanozymes in the generation and elimination of ROS, they play an important role in the occurrence, development, and treatment of different oral diseases. The application of nanozymes in dental materials and oral disease treatment was introduced, including the latest advances in their use for dental caries, pulpitis, jaw osteomyelitis, periodontitis, oral mucosal diseases, temporomandibular joint disorders, and oral tumors. Future approaches were also summarized and proposed based on the characteristics of these diseases.</div></div><div><h3>Significance</h3><div>This review will guide biomedical researchers and oral clinicians to understand the mechanisms and applications of nanozymes in the therapy of oral diseases, promoting further development in the field of dental materials within the oral medication. It is anticipated that more suitable therapeutic agents or dental materials encapsulating nanozymes, specifically designed for the oral environment and simpler for clinical utilization, will emerge in the forthcoming future.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1710-1728"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141896287","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":"A comparison of different cleaning approaches for blood contamination after curing universal adhesives on the dentine surface","authors":"Ting Liu ,&nbsp;Haifeng Xie ,&nbsp;Chen Chen","doi":"10.1016/j.dental.2024.07.035","DOIUrl":"10.1016/j.dental.2024.07.035","url":null,"abstract":"<div><h3>Objective</h3><div>This study compared the effectiveness of various cleaning approaches, including spray rinsing, repreparing with diamond burs, and using phosphoric acid or sodium hypochlorite alone or with polyphenols (resveratrol or myricetin), in removing blood contamination from the dentine after adhesive light-curing.</div></div><div><h3>Methods</h3><div>The contact angles of the treated surfaces were measured and scanning electron microscopy/ energy dispersive X-ray spectroscopy observation was performed. The bond strength and nanoleakage were assessed, and in situ zymography was performed before and after aging. Interactions between matrix metalloproteinase (MMP)−9 and polyphenols were evaluated using molecular dynamics and rhMMP-9 inhibition analyses. The destruction of sodium hypochlorite on collagen and the resistance of polyphenols-treated dentine collagen to enzymolysis were evaluated using the hydroxyproline (HYP) assay. The effect of polyphenols on dentine collagen crosslinking was assessed by Fourier Transform Infrared Spectroscopy.</div></div><div><h3>Results</h3><div>The repreparation group had the lowest contact angle compared to the other groups. The spray rinsing group had the lowest bond strength and highest amounts of nanoleakage. Cleaning with phosphoric acid or sodium hypochlorite alone removed the blood contaminants and parts of the adhesive; moreover, applying polyphenols further improved the bond strength and decreased nanoleakage and MMP activity after aging. Both polyphenols inhibited rhMMP-9 activity and promoted collagen crosslinking. Sodium hypochlorite showed the maximum HYP release when used alone, which was decreased after adding polyphenols.</div></div><div><h3>Significance</h3><div>Phosphoric acid or sodium hypochlorite cleaning can remove blood contamination from the dentine surface after adhesive curing, and the addition of polyphenols can improve the durability of dentine bonding.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1786-1797"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141915652","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":"Fretting-corrosion at the Implant–Abutment Interface Simulating Clinically Relevant Conditions","authors":"Yani Sun ,&nbsp;Apurwa Shukla ,&nbsp;Remya Ampadi Ramachandran ,&nbsp;Hemalatha Kanniyappan ,&nbsp;Bin Yang ,&nbsp;Rand Harlow ,&nbsp;Stephen D. Campbell ,&nbsp;Ghadeer Thalji ,&nbsp;Mathew Mathew","doi":"10.1016/j.dental.2024.08.007","DOIUrl":"10.1016/j.dental.2024.08.007","url":null,"abstract":"<div><h3>Objective</h3><div>Implant treatment is provided to individuals with normal, idealized masticatory forces and also to patients with parafunctional habits such as grinding, clenching, and bruxing. Dental erosion is a common increasing condition and is reported to affect 32 % of adults, increasing with age. This oral environment is conducive to tribocorrosion and the potential loss of materials from the implant surfaces and interfaces with prosthetic components. Although several fretting-corrosion studies have been reported, until now, no study has simulated clinically relevant micromotion. Therefore, our aim is to investigate fretting-corrosion using our new micro-fretting corrosion system, simulating clinical conditions with 5 µm motion at the implant-abutment interface under various occlusal loads and acidic exposures.</div></div><div><h3>Methods</h3><div>We simulated four conditions in an oral environment by varying the contact load (83 N and 233 N) and pH levels (3 and 6.5). The commonly used dental implant material, Grade IV titanium, and abutment material Zirconia (ZrO₂)/ Grade IV titanium were selected as testing couple materials. Artificial saliva was employed to represent an oral environment. In addition, a standard tribocorrosion protocol was followed, and the pin was controlled to oscillate on the disk with an amplitude of 5 <span><math><mi>μ</mi></math></span>m during the mastication stage. After the testing, 3D profilometry and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were utilized to analyze the worn surfaces. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to measure the metal ion release.</div></div><div><h3>Results</h3><div>Energy ratios were below 0.2, indicating a fretting regime of partial slip for all groups. Open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were analyzed to compare the electrochemical behavior among groups. As a result, corrosive damage was observed to be more in the Ti4- Ti4 groups than in Zr-Ti4 ones, whereas more mechanical damage was found in the Zr-Ti4 groups than in the Ti4-Ti4 groups. Possible mechanisms were proposed in the discussion to explain these findings.</div></div><div><h3>Significance</h3><div>The results observed from this study might be helpful to clinicians with implant selection. For example, for patients with bruxism, a titanium implant paired with a titanium abutment may be preferable, while patients with GERD may benefit more from a titanium implant paired with a zirconia abutment.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1823-1831"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142034736","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 impact of print orientation and graphene nanoplatelets on biaxial flexural strength and cytotoxicity of a 3D printable resin for occlusal splints","authors":"Klara Janjić ,&nbsp;Angelika Valentova ,&nbsp;Sonia Arellano ,&nbsp;Angelika Unterhuber ,&nbsp;Arno Krause ,&nbsp;Gunpreet Oberoi ,&nbsp;Ewald Unger ,&nbsp;Hassan Ali Shokoohi Tabrizi ,&nbsp;Andreas Schedle","doi":"10.1016/j.dental.2024.07.031","DOIUrl":"10.1016/j.dental.2024.07.031","url":null,"abstract":"<div><h3>Objectives</h3><div>3D printing found its way into various medical applications and could be particularly beneficial for dentistry. Currently, materials for 3D printing of occlusal splints lack mechanical strength compared to polymethyl methacrylate (PMMA) used for standard milling of occlusal splints. It is known that print orientation and graphene nanoplatelets (GNP) can increase biaxial strength in a variety of materials. Thus, the aim of this study was to assess if adjustment of print orientation and addition of GNP improve biaxial strength and if they affect cytotoxicity of a 3D printable resin for occlusal splints.</div></div><div><h3>Methods</h3><div>Specimens were printed vertically and horizontally with a stereolithography (SLA) printer and multilayered GNP powder was added to the resin at different concentrations. Printed specimens were characterized by Raman spectroscopy, optical profilometer analysis and scanning electron microscopy. Biaxial strength was evaluated by biaxial flexural testing. Cytotoxicity of specimens on L929 and gingival stromal cells (GSC) was assessed by the toxdent test, the resazurin-based toxicity assay and live-dead staining.</div></div><div><h3>Results</h3><div>Horizontally printed specimens showed significantly higher biaxial strength and lower deformation. GNP did not improve biaxial strength and material deformation of 3D-printed resins. None of the specimens were cytotoxic to L929 cells or GSC.</div></div><div><h3>Significance</h3><div>Print orientation in SLA printing has a significant impact on biaxial strength and material deformation. 3D printable materials can reach comparable or even improved biaxial strength compared to PMMA when using the optimal print orientation while GNP has no beneficial effects on the biaxial strength of resins for 3D printing of occlusal splints.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1742-1752"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141905295","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":"Changes in the composition and mechanical properties of dentin in mouse models of diabetes","authors":"K. Tang ,&nbsp;S. Ceteznik ,&nbsp;M. Kim ,&nbsp;K.E. Bornfeldt ,&nbsp;J.E. Kanter ,&nbsp;H. Zhang ,&nbsp;D.D. Arola","doi":"10.1016/j.dental.2024.09.010","DOIUrl":"10.1016/j.dental.2024.09.010","url":null,"abstract":"<div><h3>Objectives</h3><div>This study employed mouse models of type 1 (T1D) and type 2 (T2D) diabetes to characterize the changes in tooth dentin composition and its mechanical properties.</div></div><div><h3>Methods</h3><div>Thirty-two mice were used in this study and divided into T1D, T2D and corresponding control groups. Mandibles were extracted 12 weeks after the onset of diabetes, and dentin from the first molars was evaluated in varying regions of the root. The composition was assessed using Raman Spectroscopy. Nanoindentation and Vickers indentation were employed to study the mechanical properties of the tissue. Statistical significance was evaluated by two-way analysis of variance with respect to the diabetic group and region of the tooth (p ≤ 0.05).</div></div><div><h3>Results</h3><div>In the T2D model, the mineral-to-collagen ratio, hardness, and storage modulus of the intertubular dentin were significantly reduced compared to tissue from the controls, especially in the cervical regions of the tooth. The reduction in the mineral-to-collagen ratio was also observed in the T1D model, but changes in nanomechanical properties were not evident. However, the bulk hardness of the teeth in the T1D model was lower than in the littermate controls. Optical microscopy revealed significant wear of the tooth crowns in both models of diabetes, which appear to result from parafunctional activities.</div></div><div><h3>Conclusion</h3><div>This study suggests that both type 1 and type 2 models of diabetes are associated with detrimental changes in dentin.</div></div><div><h3>Clinical significance</h3><div>Better understanding of how diabetes affects dentin and the contributing mechanisms will be key to improving treatments for people with diabetes.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 2017-2024"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142338148","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 effects of optimized microstructured surfaces on bond strength and durability of NPJ-printed zirconia","authors":"Yuhan Ma ,&nbsp;Huihua Wang ,&nbsp;Yang Xiang ,&nbsp;Mingxing Li ,&nbsp;Dongni Shen ,&nbsp;Sisi Zhang ,&nbsp;Xiaojian Zhou ,&nbsp;Jun An ,&nbsp;Ying Shi ,&nbsp;Baiping Fu","doi":"10.1016/j.dental.2024.09.016","DOIUrl":"10.1016/j.dental.2024.09.016","url":null,"abstract":"<div><h3>Objectives</h3><div>This study was to investigate the effects of optimized microstructured surfaces on bond strength and bond durability of the latest nanoparticle jetting (NPJ)-printed zirconia.</div></div><div><h3>Methods</h3><div>Zirconia microstructured surfaces with different geometries and void volume were analyzed through three-dimensional finite element analysis for surface micromorphology optimization. Zirconia disks and cylinders were additively manufactured by an NPJ 3D printer (N = 128). They were randomly divided into four groups based on surface micromorphology optimization and airborne-particle abrasion (APA) treatment before they were bonded using 10-methacryloloxydecyl dihydrogen phosphate (MDP) containing resin cement (Clearfil SA luting cement). The shear bond strengths (SBSs) were tested before and after 10,000 thermocycles and were analyzed by one-way ANOVA analysis. Failure modes were determined by optical microscopy. Zirconia surfaces were analyzed with X-ray diffraction, scanning electron microscopy, and three-dimensional interference microscopy.</div></div><div><h3>Results</h3><div>The optimized microstructured surface was characterized by circular microstructures with 60 % void volume, about 20 µm of depths, about 10 µm of undercuts, and consistent beam widths. The optimized microstructured surface combined with APA treatment and MDP-containing resin cement possessed the highest SBSs both before and after thermocycling aging (P＜0.05). The greater reductions of zirconia bond strengths occurred when the zirconia were not treated with APA (P＜0.05).</div></div><div><h3>Significance</h3><div>The optimized microstructured zirconia surface with circular microstructures and 60 % void volume fabricated by the latest NPJ printing technology could greatly enhance the zirconia bond strength and durability in combination with APA treatment and application of MDP-containing resin cement, which might be promising for adhesively bonded indirect restorations of NPJ-printed zirconia.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1991-1999"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142338154","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":"Colloidal platinum nanoparticles enhance resin-dentin bonding durability","authors":"Yuan Yuan ,&nbsp;Papichaya Intajak ,&nbsp;Norihito Sakaguchi ,&nbsp;Shihchun Ting ,&nbsp;Hongbo Zhang ,&nbsp;Takatsumi Ikeda ,&nbsp;Shuhei Hoshika ,&nbsp;Hidehiko Sano ,&nbsp;Atsushi Tomokiyo","doi":"10.1016/j.dental.2024.09.015","DOIUrl":"10.1016/j.dental.2024.09.015","url":null,"abstract":"<div><h3>Objectives</h3><div>This study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives.</div></div><div><h3>Methods</h3><div>Sixty non-carious human maxillary premolars were subjected to microtensile bond strength (µTBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SE-SUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The µTBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The µTBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (α = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations.</div></div><div><h3>Results</h3><div>The application of CPN significantly prevented a decline in the µTBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultra-morphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed.</div></div><div><h3>Significance</h3><div>CPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 2034-2042"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363690","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":"Characterization of experimental resin composites with cholesteryl methacrylate organic matrix – Part 2","authors":"Julyana Dumas Santos Silva ,&nbsp;Letícia Nunes de Almeida ,&nbsp;Antônio Silva Machado ,&nbsp;Amanda Alves de Oliveira ,&nbsp;Luiza Santos Cardoso ,&nbsp;Cristhiane Gonçalves ,&nbsp;Isaac Yves Lopes de Macêdo ,&nbsp;Eric de Souza Gil ,&nbsp;Crisnicaw Veríssimo ,&nbsp;Karla de Aleluia Batista ,&nbsp;Luciano Morais Lião ,&nbsp;Carlos Estrela ,&nbsp;Ricardo Menegatti ,&nbsp;Lawrence Gonzaga Lopes","doi":"10.1016/j.dental.2024.07.037","DOIUrl":"10.1016/j.dental.2024.07.037","url":null,"abstract":"<div><h3>Objective</h3><div>The aim of this study was to evaluate the degree of conversion (%), flexural strength (MPa), elastic modulus (GPa), compressive strength (MPa), Knoop microhardness (KHN), post-gel shrinkage (%) and prediction of ideal concentration of cholesteryl methacrylate (CM) in experimental resins.</div></div><div><h3>Methods</h3><div>Four formulations were manipulated (F): F1, control group, (0 % CM); F2 (15 % CM); F3 (19.8 % CM) and F4 (30 % CM). Bis-GMA and CM percentages were determined using Statistica™ software. For the degree of conversion test, Raman spectroscopy was used. To testing flexural strength, elastic modulus and compressive strength, a universal testing machine was used. For the Knoop microhardness test five indentations were made in each sample. Post-gel shrinkage was determined using the strain gauge method. Statistica™ software processed all data obtained in this study. Results were submitted to one-way ANOVA and Tukey's post hoc tests (α = 0.05).</div></div><div><h3>Results</h3><div>Better performance was observed for F2 (15 % CM) and F3 (19,8 % CM) for degree of conversion, elastic modulus and post-gel shrinkage. For Knoop microhardness F2 (15 % CM), F3 (19,8 % CM) and F4 (30 % CM) showed higher values than F1 (0 % CM). For flexural strength F1 (0 % CM) and F3 (19,8 %) were similar and F4 showed the lowest values and for compressive strength F1 (0 % CM) showed the highest values. For mixture designs analysis data, concentrations ≤ 25 % of CM would provide better results.</div></div><div><h3>Significance</h3><div>Addition of CM at concentrations lower than 30 % contributed to a significant increase in the degree of conversion, microhardness values, elastic modulus and reduction of post-gel shrinkage.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages e63-e71"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141900328","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":"Improving accuracy and efficiency of the machined PEEK denture based on NSGA-II integrated GABP neural network","authors":"Hao Jia ,&nbsp;Shuting Liang ,&nbsp;Ji Zhao ,&nbsp;Jingjin Li ,&nbsp;Handa Dai ,&nbsp;Shijun Ji","doi":"10.1016/j.dental.2024.07.011","DOIUrl":"10.1016/j.dental.2024.07.011","url":null,"abstract":"<div><h3>Objectives</h3><div>The polymer polyetheretherketone (PEEK) is gradually being used in dental restorations because of its excellent mechanical properties, chemical resistance, fatigue resistance, thermal stability, radiation translucency and good biocompatibility. To process PEEK dentures with lower surface roughness as quickly as possible, the non-dominated sorting genetic algorithm-II (NSGA-II) integrated genetic algorithm back propagation (GABP) neural network was proposed, which can adjust the combination of process parameters for milling PEEK dentures.</div></div><div><h3>Methods</h3><div>The PEEK machining was conducted using a four-axis dental milling machine at different process parameters. The surface roughness of PEEK dentures was characterized using surface roughness profiler and scanning electron microscopy (SEM). The optimum machining performance of milling PEEK dentures was investigated using a multi-objective optimization model named as NSGA-II integrated GABP neural network algorithm. The surface roughness (Ra) and material removal rate (MRR) were used as optimization objectives.</div></div><div><h3>Results</h3><div>The multi-objective optimization model effectively improved surface roughness and machining efficiency for milling PEEK dentures. The validation experiments showed that the surface roughness of all PEEK dentures was less than 0.2<span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>, which was within the range of surface roughness set in this paper. The GABP surface roughness prediction model had an average error of 6 %. For the same surface roughness value, the optimized milling parameters all had a greater material removal rate.</div></div><div><h3>Significance</h3><div>The research results can improve current PEEK denture CAD/CAM technology by providing appropriate milling parameters using NSGA-II integrated GABP algorithm.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages e82-e94"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141911015","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":"Emerging technologies for the evaluation of spatio-temporal polymerisation changes in flowable vs. sculptable dental resin-based composites","authors":"Danijela Marovic ,&nbsp;Håvard J. Haugen ,&nbsp;Matej Par ,&nbsp;Stefanie Linskens ,&nbsp;Emile Mensikova ,&nbsp;Visnja Negovetic Mandic ,&nbsp;Sander Leeuwenburgh ,&nbsp;Liebert P. Nogueira ,&nbsp;Pekka K. Vallittu ,&nbsp;Qianli Ma","doi":"10.1016/j.dental.2024.09.002","DOIUrl":"10.1016/j.dental.2024.09.002","url":null,"abstract":"<div><h3>Background</h3><div>This study presents a novel multi-technique approach that integrates micro-CT and optical photothermal infrared spectroscopy (O-PTIR) to evaluate polymerisation differences, so-called spatio-temporal polymerisation properties, between flowable and sculptable dental resin-based composites.</div></div><div><h3>Methods</h3><div>Ten commercially available dental composites were investigated, including flowable and sculptable counterparts from the same manufacturer. Eight parameters were evaluated: short-term polymerisation characteristics (degree of conversion after 5 min, maximum polymerisation rate, time to reach maximum polymerisation rate) was measured using ATR-FTIR with real-time monitoring; changes in the degree of conversion with depth were evaluated with O-PTIR, 3D visualisation of shrinkage patterns, overall volumetric shrinkage, depth-specific shrinkage, and porosity were measured using micro-CT; surface morphology with detailed measurements of elemental composition was characterised using SEM/EDX; light transmittance was analysed with a NIST-referenced spectrometer.</div></div><div><h3>Results</h3><div>The study found that the increase in filler weight and volume ratio reduced the degree of conversion and polymerisation shrinkage, while moderately influencing the maximum polymerisation rates. The time to reach maximum polymerisation rates and light transmittance were not dependent on the filler amount. O-PTIR assessed a depth-dependent decrease in the degree of conversion for both composite types, with flowable composites generally showing a greater decrease in the degree of conversion than sculptable composites, except for bulk-fill composites. Micro-CT scans showed significantly higher flowable shrinkage values than their sculptable counterparts, highlighting the performance differences between the two types of composites.</div></div><div><h3>Conclusions</h3><div>The findings of this study have practical implications for the selection and use of dental composites. Flowable composites, despite their higher degrees of conversion and polymerisation rates, also exhibit higher volumetric shrinkage, which can be detrimental for clinical applications. The new measurement methods used in this study provide a comprehensive overview of the polymerisation behaviour of commercially available dental composites, offering valuable insights for material optimisation.</div></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":"40 11","pages":"Pages 1895-1908"},"PeriodicalIF":4.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142277761","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}