Pub Date : 2024-06-07DOI: 10.1016/j.dental.2024.05.030
Tina Maleki, John Meinen, Andrea Coldea, Marcel Reymus, Daniel Edelhoff, Bogna Stawarczyk
Objectives: To investigate the flexural strength (FS), elastic modulus (E), Martens hardness (HM), water sorption (wsp), water solubility (wsl) and degree of conversion (DC) of 3D-printed, milled and injection molded splint materials.
Methods: Specimens (N = 1140) were fabricated from five 3D-printed (GR-22 flex, GR-10 guide, ProArt Print Splint clear, V-Print Splint, V-Print Splint comfort), five milled (BioniCut, EldyPlus, ProArt CAD Splint clear, Temp Premium Flexible, Thermeo) and two injection molded (PalaXPress clear, Pro Base Cold) materials. FS, E, HM, wsp, wsl and DC were tested initially (24 h, 37 °C, H2O), after water storage (90 d, 37 °C, H2O) as well as after thermal cycling (5000 thermal cycles, 5/55 °C). Data were analyzed with Kolmogorov-Smirnov, Kruskal- Wallis, Mann-Whitney U test and Spearman's correlation (p < 0.05).
Results: Initially, the mean flexural strength values ranged from 1.9 to 90.7 MPa for printed, 3.8 to 107 MPa for milled and 99.7 to 102 MPa for injection molded materials. The initial mean elastic modulus values were 0.0 to 2.4 GPa for printed, 0.1 to 2.7 GPa for milled and 2.8 GPa for injection molded materials. The initial mean Martens hardness values were 14.5 to 126 N/mm2 for printed, 50.2 to 171 N/mm2 for milled and 143 to 151 N/mm2 for injection molded materials. Initially, the mean water sorption values ranged from 23.1 to 41.2 μg/mm3 for printed, 4.5 to 23.5 μg/mm3 for milled and from 22.5 to 23.3 μg/ mm3 for injection molded materials. The initial mean water solubility values ranged from 2.2 to 7.1 μg/mm3 for printed, 0.0 to 0.5 μg/mm3 for milled and 0.1 to 0.3 μg/mm3 for injection molded materials. After water storage and thermal cycling most of the values decreased and some increased. The mean DC values ranged initially from 72.3 to 94.5 %, after water storage from 74.2 to 96.8 % and after thermal cycling from 75.6 to 95.4 % for the printed materials.
Significance: The mechanical and physical properties of printed, milled and injection molded materials for occlusal devices vary and are influenced by aging processes. For clinical applications, materials need to be chosen according to the specific indications.
{"title":"Mechanical and physical properties of splint materials for oral appliances produced by additive, subtractive and conventional manufacturing.","authors":"Tina Maleki, John Meinen, Andrea Coldea, Marcel Reymus, Daniel Edelhoff, Bogna Stawarczyk","doi":"10.1016/j.dental.2024.05.030","DOIUrl":"https://doi.org/10.1016/j.dental.2024.05.030","url":null,"abstract":"<p><strong>Objectives: </strong>To investigate the flexural strength (FS), elastic modulus (E), Martens hardness (HM), water sorption (w<sub>sp</sub>), water solubility (w<sub>sl</sub>) and degree of conversion (DC) of 3D-printed, milled and injection molded splint materials.</p><p><strong>Methods: </strong>Specimens (N = 1140) were fabricated from five 3D-printed (GR-22 flex, GR-10 guide, ProArt Print Splint clear, V-Print Splint, V-Print Splint comfort), five milled (BioniCut, EldyPlus, ProArt CAD Splint clear, Temp Premium Flexible, Thermeo) and two injection molded (PalaXPress clear, Pro Base Cold) materials. FS, E, HM, w<sub>sp</sub>, w<sub>sl</sub> and DC were tested initially (24 h, 37 °C, H<sub>2</sub>O), after water storage (90 d, 37 °C, H<sub>2</sub>O) as well as after thermal cycling (5000 thermal cycles, 5/55 °C). Data were analyzed with Kolmogorov-Smirnov, Kruskal- Wallis, Mann-Whitney U test and Spearman's correlation (p < 0.05).</p><p><strong>Results: </strong>Initially, the mean flexural strength values ranged from 1.9 to 90.7 MPa for printed, 3.8 to 107 MPa for milled and 99.7 to 102 MPa for injection molded materials. The initial mean elastic modulus values were 0.0 to 2.4 GPa for printed, 0.1 to 2.7 GPa for milled and 2.8 GPa for injection molded materials. The initial mean Martens hardness values were 14.5 to 126 N/mm<sup>2</sup> for printed, 50.2 to 171 N/mm<sup>2</sup> for milled and 143 to 151 N/mm<sup>2</sup> for injection molded materials. Initially, the mean water sorption values ranged from 23.1 to 41.2 μg/mm<sup>3</sup> for printed, 4.5 to 23.5 μg/mm<sup>3</sup> for milled and from 22.5 to 23.3 μg/ mm<sup>3</sup> for injection molded materials. The initial mean water solubility values ranged from 2.2 to 7.1 μg/mm<sup>3</sup> for printed, 0.0 to 0.5 μg/mm<sup>3</sup> for milled and 0.1 to 0.3 μg/mm<sup>3</sup> for injection molded materials. After water storage and thermal cycling most of the values decreased and some increased. The mean DC values ranged initially from 72.3 to 94.5 %, after water storage from 74.2 to 96.8 % and after thermal cycling from 75.6 to 95.4 % for the printed materials.</p><p><strong>Significance: </strong>The mechanical and physical properties of printed, milled and injection molded materials for occlusal devices vary and are influenced by aging processes. For clinical applications, materials need to be chosen according to the specific indications.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141292891","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}
Objectives: To investigate a near-infrared-to-blue luminescence upconversion curing method for polymerizing resin cements under zirconia discs.
Methods: Lava zirconia discs of different thicknesses (0.5-2.0 mm) were manufactured. First, the transmittances of the NIR and two blue lights (BLs) (LED and halogen lights) through these discs were measured. Second, NaYF4:Yb3+/Tm3+ upconversion phosphor (UP) powder was milled into 0.5-μm particle sizes. A light-curable resin cement VariolinkII base was chosen as the control (UP0), and an experimental cement (UP5) was prepared by adding 5 % UPs. These two cements were examined using multiphoton excitation microscopy for particle distribution. UP5 and UP0 were polymerized with or without zirconia shielding then subjected to a microhardness test. A multifold analysis was performed to examine the effects of zirconia thickness, curing protocols (pure BL or combined BL and NIR curing), and cement type.
Results: The transmittance of NIR was superior to that of BL through zirconia discs of all thicknesses. UP particles were homogeneously distributed in UP5 and emitted blue luminescence under 980-nm NIR excitation. UP5 showed higher microhardness values than UP0 under any curing protocol or zirconia shielding condition. The combination of 20-s BL and 40-s NIR curing yielded the highest microhardness in uncovered UP5. However, combining 40-s BL and 20-s NIR curing surpassed the other groups when the zirconia discs were thicker than 0.5 mm.
Significance: NIR exhibits higher transmission through zirconia than BL. UP particles work as strengthen fillers and photosensitizers in cements. NIR upconversion curing could be a new strategy for polymerizing resin cements under thick zirconia restorations.
{"title":"Application of near-infrared-to-blue upconversion luminescence for the polymerization of resin cements through zirconia discs.","authors":"Yu-Cheng Chou, Shu-Fen Chuang, Jui-Che Lin, Chia-Ling Li, Bang-Yan Liu, Chung-Lin Lee","doi":"10.1016/j.dental.2024.06.005","DOIUrl":"https://doi.org/10.1016/j.dental.2024.06.005","url":null,"abstract":"<p><strong>Objectives: </strong>To investigate a near-infrared-to-blue luminescence upconversion curing method for polymerizing resin cements under zirconia discs.</p><p><strong>Methods: </strong>Lava zirconia discs of different thicknesses (0.5-2.0 mm) were manufactured. First, the transmittances of the NIR and two blue lights (BLs) (LED and halogen lights) through these discs were measured. Second, NaYF<sub>4</sub>:Yb<sup>3+</sup>/Tm<sup>3+</sup> upconversion phosphor (UP) powder was milled into 0.5-μm particle sizes. A light-curable resin cement VariolinkII base was chosen as the control (UP0), and an experimental cement (UP5) was prepared by adding 5 % UPs. These two cements were examined using multiphoton excitation microscopy for particle distribution. UP5 and UP0 were polymerized with or without zirconia shielding then subjected to a microhardness test. A multifold analysis was performed to examine the effects of zirconia thickness, curing protocols (pure BL or combined BL and NIR curing), and cement type.</p><p><strong>Results: </strong>The transmittance of NIR was superior to that of BL through zirconia discs of all thicknesses. UP particles were homogeneously distributed in UP5 and emitted blue luminescence under 980-nm NIR excitation. UP5 showed higher microhardness values than UP0 under any curing protocol or zirconia shielding condition. The combination of 20-s BL and 40-s NIR curing yielded the highest microhardness in uncovered UP5. However, combining 40-s BL and 20-s NIR curing surpassed the other groups when the zirconia discs were thicker than 0.5 mm.</p><p><strong>Significance: </strong>NIR exhibits higher transmission through zirconia than BL. UP particles work as strengthen fillers and photosensitizers in cements. NIR upconversion curing could be a new strategy for polymerizing resin cements under thick zirconia restorations.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141292889","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}
This work aims to demonstrate the effect of ZrO2 and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO2 + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035-1.152 g/cm3. X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91-100 MPa, 0.48-0.51 GPa, 9.122-9.705 MPa.m1/2, 0.66-0.815, 51.03-42.78 MPa and 499-663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm3 was observed for PZM2, whereas the maximum volume loss of 5.64 mm3 is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials.
{"title":"Synergetic impact of MgO on PMMA-ZrO<sub>2</sub> hybrid composites: Evaluation of structural, morphological and improved mechanical behavior for dental applications.","authors":"Savita Kumari, Anuj Verma, Rajat Kumar Mishra, Sarvesh Kumar Avinashi, Shweta, Shweta Singh, Priyatama Behera, Jitendra Rao, Rakesh Kumar Gautam, Bijay Laxmi Pradhan, Krishna Kishor Dey, Manasi Ghosh, Monalisa Mishra, Chandkiram Gautam","doi":"10.1016/j.dental.2024.06.006","DOIUrl":"https://doi.org/10.1016/j.dental.2024.06.006","url":null,"abstract":"<p><p>This work aims to demonstrate the effect of ZrO<sub>2</sub> and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO<sub>2</sub> + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035-1.152 g/cm<sup>3</sup><sub>.</sub> X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91-100 MPa, 0.48-0.51 GPa, 9.122-9.705 MPa.m<sup>1/2</sup><sub>,</sub> 0.66-0.815, 51.03-42.78 MPa and 499-663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm<sup>3</sup> was observed for PZM2, whereas the maximum volume loss of 5.64 mm<sup>3</sup> is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141292892","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}
Pub Date : 2024-06-07DOI: 10.1016/j.dental.2024.06.008
Iris Lamparth, Jörg Angermann, Pascal Fässler, Thomas Schnur, Bernadette Graff, Coralie Ohl, Jacques Lalevée, Yohann Catel
Objectives: Hydroperoxides are key constituents of two-component dental materials. The objective of this study was to evaluate the influence of the hydroperoxide structure on the reactivity and on the mechanical properties of self-cure composites.
Methods: Hydroperoxides HP1-3 were synthesized by selective catalytic oxidation of the corresponding para-substituted cumene precursors and isolated in high purity. They were characterized by 1H NMR and 13C NMR spectroscopy. 16 self-cure composites, based on the redox initiator system hydroperoxide (Cumene hydroperoxide (CHP), HP1-3 or tert.-Amyl hydroperoxide (TAH))/polymerizable thiourea ATU1/copper(II) acetylacetonate, were formulated in Sulzer Mixpac two-component syringes. An equimolar hydroperoxide/ATU1 ratio was selected for each self-cure composite. The reactivity and the final double-bond conversions obtained with these two-component materials was assessed using RT-FTIR spectroscopy. The flexural strength and modulus were measured using a three-point bending setup, after storage of the specimens for 45 min at 37 °C (dry) and for 24 h in water at 37 °C. The working time of each self-cure composite was measured using an oscillating rheometer.
Results: CHP derivatives bearing an electron withdrawing group (HP2: ester or HP3: nitrile) in the para position were found to be more reactive than CHP, whereas the compound bearing an electron donating group (tert-butyl, HP1) was less reactive; molecular modelling data were reported for a better understanding of this structure/reactivity/efficiency relationship. All CHP derivatives were more reactive than the aliphatic hydroperoxide TAH. Excellent mechanical properties were obtained with self-cure composites containing either CHP or a para-functionalized CHP derivative. By carefully selecting the amounts of oxidizing/reducing agents and metal catalyst, suitable working times can be obtained with all evaluated hydroperoxides. HP3, thanks to its high reactivity, is nonetheless the most promising compound.
Significance: The curing rate of self-cure composites can be adapted by modifying the structure of the hydroperoxide. In agreement with molecular modelling data, the incorporation of CHP derivatives bearing an electron withdrawing group in the para position is particularly attractive. Indeed, due to a significant reactivity enhancement, the desired properties (working time, flexural strength/modulus) can be obtained by incorporating moderate amounts of hydroperoxide/acylthiourea as well as particularly low contents of metal catalyst to the two-component dental materials.
{"title":"Influence of the hydroperoxide structure on the reactivity and mechanical properties of self-cure dental composites.","authors":"Iris Lamparth, Jörg Angermann, Pascal Fässler, Thomas Schnur, Bernadette Graff, Coralie Ohl, Jacques Lalevée, Yohann Catel","doi":"10.1016/j.dental.2024.06.008","DOIUrl":"https://doi.org/10.1016/j.dental.2024.06.008","url":null,"abstract":"<p><strong>Objectives: </strong>Hydroperoxides are key constituents of two-component dental materials. The objective of this study was to evaluate the influence of the hydroperoxide structure on the reactivity and on the mechanical properties of self-cure composites.</p><p><strong>Methods: </strong>Hydroperoxides HP1-3 were synthesized by selective catalytic oxidation of the corresponding para-substituted cumene precursors and isolated in high purity. They were characterized by <sup>1</sup>H NMR and <sup>13</sup>C NMR spectroscopy. 16 self-cure composites, based on the redox initiator system hydroperoxide (Cumene hydroperoxide (CHP), HP1-3 or tert.-Amyl hydroperoxide (TAH))/polymerizable thiourea ATU1/copper(II) acetylacetonate, were formulated in Sulzer Mixpac two-component syringes. An equimolar hydroperoxide/ATU1 ratio was selected for each self-cure composite. The reactivity and the final double-bond conversions obtained with these two-component materials was assessed using RT-FTIR spectroscopy. The flexural strength and modulus were measured using a three-point bending setup, after storage of the specimens for 45 min at 37 °C (dry) and for 24 h in water at 37 °C. The working time of each self-cure composite was measured using an oscillating rheometer.</p><p><strong>Results: </strong>CHP derivatives bearing an electron withdrawing group (HP2: ester or HP3: nitrile) in the para position were found to be more reactive than CHP, whereas the compound bearing an electron donating group (tert-butyl, HP1) was less reactive; molecular modelling data were reported for a better understanding of this structure/reactivity/efficiency relationship. All CHP derivatives were more reactive than the aliphatic hydroperoxide TAH. Excellent mechanical properties were obtained with self-cure composites containing either CHP or a para-functionalized CHP derivative. By carefully selecting the amounts of oxidizing/reducing agents and metal catalyst, suitable working times can be obtained with all evaluated hydroperoxides. HP3, thanks to its high reactivity, is nonetheless the most promising compound.</p><p><strong>Significance: </strong>The curing rate of self-cure composites can be adapted by modifying the structure of the hydroperoxide. In agreement with molecular modelling data, the incorporation of CHP derivatives bearing an electron withdrawing group in the para position is particularly attractive. Indeed, due to a significant reactivity enhancement, the desired properties (working time, flexural strength/modulus) can be obtained by incorporating moderate amounts of hydroperoxide/acylthiourea as well as particularly low contents of metal catalyst to the two-component dental materials.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141292890","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}
Objectives: This study conducted a comprehensive comparative analysis of three intraoral scanners (CEREC Primescan, TRIOS, CEREC Omnicam) and a lab scanner (inEosX5) assessing their precision in simulating subgingival tooth preparations.
Methods: Utilizing a dental simulation mannequin with a 3D-printed resin structure, 100 structures with depths ranging from 0.5 to 4.0 mm were created within a square mimicking a rectangular tank surface. Four scanner groups (A-D) and five subgroups were established. Two digitization methods, a customized parallelometer and an intraoral simulation, were applied, ensuring a standardized scanning sequence. Trueness was evaluated by comparing CAD-calculated surface areas with actual dimensions, and qualitative trueness analysis was conducted using MeshLab. Surface areas were computed using the formula SA = 2lw + 2lh + 2wh. Statistical analyses, including Pearson's correlation coefficient, Kolmogorov-Smirnoff and Levene's tests, three-way ANOVA, and paired sample t-tests, elucidated relationships and differences (a=0.05).
Results: A robust correlation (r = 0.850, p < 0.001) between intraoral scanner choice and scanned area depth was found. Inverse correlations were noted for experimental methods. Three-way ANOVA demonstrated significant scanner-depth interaction (F(12,760) = 760.801, p < 0.001).
Significance: Emphasizing high-resolution sensors and advanced technologies, the study underscores the optimal choice for subgingival digitization, acknowledging variations among scanners.
研究目的:本研究对三种口内扫描仪(CEREC Primescan、TRIOS、CEREC Omnicam)和一种实验室扫描仪(inEosX5)进行了全面的比较分析,评估它们在模拟龈下牙预备方面的精确度:利用带有 3D 打印树脂结构的牙科模拟人体模型,在模拟矩形槽表面的正方形内创建了 100 个深度为 0.5 至 4.0 毫米的结构。共设立了四个扫描仪组(A-D)和五个子组。应用了两种数字化方法,一种是定制的平行计,另一种是口内模拟,以确保标准化的扫描顺序。通过比较 CAD 计算的表面积和实际尺寸来评估真实度,并使用 MeshLab 对真实度进行定性分析。表面积的计算公式为 SA = 2lw + 2lh + 2wh。统计分析包括皮尔逊相关系数、Kolmogorov-Smirnoff 和 Levene 检验、三向方差分析和配对样本 t 检验,以阐明关系和差异(a=0.05):结果:强相关性(r = 0.850,p 显著性:研究强调了高分辨率传感器和先进技术,强调了龈下数字化的最佳选择,同时承认了扫描仪之间的差异。
{"title":"Beyond the surface: A comparative study of intraoral scanners in subgingival configuration scanning.","authors":"Petros Mourouzis, Dimitrios Dionysopoulos, Christos Gogos, Kosmas Tolidis","doi":"10.1016/j.dental.2024.06.004","DOIUrl":"https://doi.org/10.1016/j.dental.2024.06.004","url":null,"abstract":"<p><strong>Objectives: </strong>This study conducted a comprehensive comparative analysis of three intraoral scanners (CEREC Primescan, TRIOS, CEREC Omnicam) and a lab scanner (inEosX5) assessing their precision in simulating subgingival tooth preparations.</p><p><strong>Methods: </strong>Utilizing a dental simulation mannequin with a 3D-printed resin structure, 100 structures with depths ranging from 0.5 to 4.0 mm were created within a square mimicking a rectangular tank surface. Four scanner groups (A-D) and five subgroups were established. Two digitization methods, a customized parallelometer and an intraoral simulation, were applied, ensuring a standardized scanning sequence. Trueness was evaluated by comparing CAD-calculated surface areas with actual dimensions, and qualitative trueness analysis was conducted using MeshLab. Surface areas were computed using the formula SA = 2lw + 2lh + 2wh. Statistical analyses, including Pearson's correlation coefficient, Kolmogorov-Smirnoff and Levene's tests, three-way ANOVA, and paired sample t-tests, elucidated relationships and differences (a=0.05).</p><p><strong>Results: </strong>A robust correlation (r = 0.850, p < 0.001) between intraoral scanner choice and scanned area depth was found. Inverse correlations were noted for experimental methods. Three-way ANOVA demonstrated significant scanner-depth interaction (F(12,760) = 760.801, p < 0.001).</p><p><strong>Significance: </strong>Emphasizing high-resolution sensors and advanced technologies, the study underscores the optimal choice for subgingival digitization, acknowledging variations among scanners.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141287484","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}
Pub Date : 2024-06-05DOI: 10.1016/j.dental.2024.05.022
Talal Bin Irshad, Giulia Pascoletti, Francesco Bianconi, Elisabetta M Zanetti
Objectives: Nowadays, a wide variety of software for 3D reconstruction from CT scans is available; they differ for costs, capabilities, a priori knowledge, and, it is not trivial to identify the most suitable one for specific purposes. The article is aimed to provide some more information, having set up various metrics for the evaluation of different software's performance.
Methods: Metrics include software usability, segmentation quality, geometric accuracy, mesh properties and Dice Similarity Coefficient (DSC). Five different software have been considered (Mimics, D2P, Blue Sky Plan, Relu, and 3D Slicer) and tested on four cases; the mandibular bone was used as a benchmark.
Results: Relu software, being based on AI, was able to solve some very intricate geometry and proved to have a very good usability. On the other side, the time required for segmentation was significantly higher than other software (reaching over twice the time required by Mimics). Geometric distances between nodes position calculated by different software usually kept below 2.5 mm, reaching 3.1 mm in some very critical area; 75th percentile q75 is generally less than 0.5 mm, with a maximum of 1.11 mm. Dealing with consistency among software, the maximum DSC value was observed between Mimics and Slicer, D2P and Mimics, and D2P and Slicer, reaching 0.96.
Significance: This work has demonstrated how mandible segmentation performance among software was generally very good. Nonetheless, differences in geometric accuracy, usability, costs and times required can be significant so that information here provided can be useful to perform an informed choice.
{"title":"Mandibular bone segmentation from CT scans: Quantitative and qualitative comparison among software.","authors":"Talal Bin Irshad, Giulia Pascoletti, Francesco Bianconi, Elisabetta M Zanetti","doi":"10.1016/j.dental.2024.05.022","DOIUrl":"https://doi.org/10.1016/j.dental.2024.05.022","url":null,"abstract":"<p><strong>Objectives: </strong>Nowadays, a wide variety of software for 3D reconstruction from CT scans is available; they differ for costs, capabilities, a priori knowledge, and, it is not trivial to identify the most suitable one for specific purposes. The article is aimed to provide some more information, having set up various metrics for the evaluation of different software's performance.</p><p><strong>Methods: </strong>Metrics include software usability, segmentation quality, geometric accuracy, mesh properties and Dice Similarity Coefficient (DSC). Five different software have been considered (Mimics, D2P, Blue Sky Plan, Relu, and 3D Slicer) and tested on four cases; the mandibular bone was used as a benchmark.</p><p><strong>Results: </strong>Relu software, being based on AI, was able to solve some very intricate geometry and proved to have a very good usability. On the other side, the time required for segmentation was significantly higher than other software (reaching over twice the time required by Mimics). Geometric distances between nodes position calculated by different software usually kept below 2.5 mm, reaching 3.1 mm in some very critical area; 75th percentile q<sub>75</sub> is generally less than 0.5 mm, with a maximum of 1.11 mm. Dealing with consistency among software, the maximum DSC value was observed between Mimics and Slicer, D2P and Mimics, and D2P and Slicer, reaching 0.96.</p><p><strong>Significance: </strong>This work has demonstrated how mandible segmentation performance among software was generally very good. Nonetheless, differences in geometric accuracy, usability, costs and times required can be significant so that information here provided can be useful to perform an informed choice.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141282544","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}
Pub Date : 2024-06-01DOI: 10.1016/j.dental.2024.04.006
Elisabeth Prause , Jeremias Hey , Florian Beuer , Jamila Yassine , Bernhard Hesse , Timm Weitkamp , Javier Gerber , Franziska Schmidt
Objectives
An increasing number of CAD/CAM (computer-aided design/computer-aided manufacturing) hybrid materials have been introduced to the dental market in recent years. In addition, CAD/CAM hybrid materials for additive manufacturing (AM) are becoming more attractive in digital dentistry. Studies on material microstructures using micro-computed tomography (µ-CT) combined with scanning electron microscopy (SEM) have only been available to a limited extent so far.
Methods
One CAD/CAM three-dimensional- (3D-) printable hybrid material (VarseoSmile Crown plus) and two CAD/CAM millable hybrid materials (Vita Enamic; Voco Grandio), as well as one direct composite material (Ceram.x duo), were included in the present study. Cylindrical samples with a diameter of 2 mm were produced from each material and investigated by means of synchrotron radiation µ-CT at a voxel size of 0.65 µm. Different samples from the same materials, obtained by cutting and polishing, were investigated by SEM.
Results
The 3D-printed hybrid material showed some agglomerations and a more irregular distribution of fillers, as well as a visible layered macrostructure and a few spherical pores due to the printing process. The CAD/CAM millable hybrid materials revealed a more homogenous distribution of ceramic particles. The direct composite material showed multiple air bubbles and microstructural irregularities based on manual processing.
Significance
The µ-CT and SEM analysis of the materials revealed different microstructures even though they belong to the same class of materials. It could be shown that µ-CT and SEM imaging are valuable tools to understand microstructure and related mechanical properties of materials.
{"title":"Microstructural investigation of hybrid CAD/CAM restorative dental materials by micro-CT and SEM","authors":"Elisabeth Prause , Jeremias Hey , Florian Beuer , Jamila Yassine , Bernhard Hesse , Timm Weitkamp , Javier Gerber , Franziska Schmidt","doi":"10.1016/j.dental.2024.04.006","DOIUrl":"10.1016/j.dental.2024.04.006","url":null,"abstract":"<div><h3>Objectives</h3><p>An increasing number of CAD/CAM (computer-aided design/computer-aided manufacturing) hybrid materials have been introduced to the dental market in recent years. In addition, CAD/CAM hybrid materials for additive manufacturing (AM) are becoming more attractive in digital dentistry. Studies on material microstructures using micro-computed tomography (µ-CT) combined with scanning electron microscopy (SEM) have only been available to a limited extent so far.</p></div><div><h3>Methods</h3><p>One CAD/CAM three-dimensional- (3D-) printable hybrid material (VarseoSmile Crown plus) and two CAD/CAM millable hybrid materials (Vita Enamic; Voco Grandio), as well as one direct composite material (Ceram.x duo), were included in the present study. Cylindrical samples with a diameter of 2 mm were produced from each material and investigated by means of synchrotron radiation µ-CT at a voxel size of 0.65 µm. Different samples from the same materials, obtained by cutting and polishing, were investigated by SEM.</p></div><div><h3>Results</h3><p>The 3D-printed hybrid material showed some agglomerations and a more irregular distribution of fillers, as well as a visible layered macrostructure and a few spherical pores due to the printing process. The CAD/CAM millable hybrid materials revealed a more homogenous distribution of ceramic particles. The direct composite material showed multiple air bubbles and microstructural irregularities based on manual processing.</p></div><div><h3>Significance</h3><p>The µ-CT and SEM analysis of the materials revealed different microstructures even though they belong to the same class of materials. It could be shown that µ-CT and SEM imaging are valuable tools to understand microstructure and related mechanical properties of materials.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0109564124000873/pdfft?md5=0093d46a931ac6a1b2b173ce6d77bd96&pid=1-s2.0-S0109564124000873-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140896676","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}
Pub Date : 2024-06-01DOI: 10.1016/j.dental.2024.05.014
Hamza Elfarraj, Franco Lizzi, Kerstin Bitter, Paul Zaslansky
Background: Root canal irrigation endodontic solutions have effects on the chemistry of dentin. Infrared spectroscopy is a non-destructive chemical characterization method where the strength of absorption often correlates with mineral or organic composition.
Objectives: To survey effects of commonly used irrigation solutions on the composition of root dentin as detected by widely-available Fourier transform infrared spectroscopy (FTIR) methods.
Methods: Electronic databases were searched for articles published between 1983 to 2023. After risk of bias assessments (OHAT), studies were grouped according to effects per irrigation solution. Inclusion criteria comprised in vitro studies that used extracted human or bovine teeth, treated by irrigation solutions characterized using FTIR spectroscopy and presenting spectral data. Publications that did not share FTIR spectra were excluded.
Results: A wide range of concentrations, durations, and methodologies have been tested but only 30 out of 3452 studies met our inclusion criteria. Different FTIR methods were used with the Attenuated Total Reflection (ATR) variant being the most common (21 studies). Investigated solutions included sodium hypochlorite (NaOCl), ethylenediaminetetraacetic-acid (EDTA), 1-hydroxyethylidene-1-1-diphosphonic-acid (HEDP), peracetic-acid (PAA), glycolic-acid (GA), and citric-acid (CA) though most focused on NaOCl and EDTA. All solutions had detectable effects on the FTIR signature of dentin. NaOCl mainly affects the organic signatures, revealing reduced amide/phosphate ratios with increasing concentrations. EDTA mainly effects the inorganic component, increasing with time and concentration, yet glycolic acid has stronger effects than EDTA on dentin. Beyond the type of irrigant and dentin exposure durations, concentration and protocol of application had strong effects. There is a lack of studies comparing similar irrigants under conditions that mimic clinical scenarios analyzing bulk sample because FTIR of powder dentin differs from bulk measurements.
Significance: The ideal root-canal irrigant should combine local disinfection properties with minimal compositional effects on healthy dentin. FTIR methods appear reliable to identify important changes in root dentin chemical composition. Such information can help understand when endodontic irrigation might lead to root degradation or possibly contribute to long term failures such as vertical fractures. Awareness of chemical damage from irrigation procedures may help clinicians select procedures that reduce deleterious effects on the root canal structures.
{"title":"Effects of endodontic root canal irrigants on tooth dentin revealed by infrared spectroscopy: a systematic literature review.","authors":"Hamza Elfarraj, Franco Lizzi, Kerstin Bitter, Paul Zaslansky","doi":"10.1016/j.dental.2024.05.014","DOIUrl":"https://doi.org/10.1016/j.dental.2024.05.014","url":null,"abstract":"<p><strong>Background: </strong>Root canal irrigation endodontic solutions have effects on the chemistry of dentin. Infrared spectroscopy is a non-destructive chemical characterization method where the strength of absorption often correlates with mineral or organic composition.</p><p><strong>Objectives: </strong>To survey effects of commonly used irrigation solutions on the composition of root dentin as detected by widely-available Fourier transform infrared spectroscopy (FTIR) methods.</p><p><strong>Methods: </strong>Electronic databases were searched for articles published between 1983 to 2023. After risk of bias assessments (OHAT), studies were grouped according to effects per irrigation solution. Inclusion criteria comprised in vitro studies that used extracted human or bovine teeth, treated by irrigation solutions characterized using FTIR spectroscopy and presenting spectral data. Publications that did not share FTIR spectra were excluded.</p><p><strong>Results: </strong>A wide range of concentrations, durations, and methodologies have been tested but only 30 out of 3452 studies met our inclusion criteria. Different FTIR methods were used with the Attenuated Total Reflection (ATR) variant being the most common (21 studies). Investigated solutions included sodium hypochlorite (NaOCl), ethylenediaminetetraacetic-acid (EDTA), 1-hydroxyethylidene-1-1-diphosphonic-acid (HEDP), peracetic-acid (PAA), glycolic-acid (GA), and citric-acid (CA) though most focused on NaOCl and EDTA. All solutions had detectable effects on the FTIR signature of dentin. NaOCl mainly affects the organic signatures, revealing reduced amide/phosphate ratios with increasing concentrations. EDTA mainly effects the inorganic component, increasing with time and concentration, yet glycolic acid has stronger effects than EDTA on dentin. Beyond the type of irrigant and dentin exposure durations, concentration and protocol of application had strong effects. There is a lack of studies comparing similar irrigants under conditions that mimic clinical scenarios analyzing bulk sample because FTIR of powder dentin differs from bulk measurements.</p><p><strong>Significance: </strong>The ideal root-canal irrigant should combine local disinfection properties with minimal compositional effects on healthy dentin. FTIR methods appear reliable to identify important changes in root dentin chemical composition. Such information can help understand when endodontic irrigation might lead to root degradation or possibly contribute to long term failures such as vertical fractures. Awareness of chemical damage from irrigation procedures may help clinicians select procedures that reduce deleterious effects on the root canal structures.</p>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198792","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}
Pub Date : 2024-06-01DOI: 10.1016/j.dental.2024.05.002
Lincoln Borges , Matthew Logan , Samuel Weber , Steven Lewis , Clark Fang , Lourenço Correr-Sobrinho , Carmem Pfeifer
Objectives
Acrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the hypothesis that hydrogen bonding reinforcement of the collagen network (with secondary or tertiary acrylamides), as well as degree of crosslinking of the polymer network (with di- or tri-functional acrylamides), can be two of the factors at play.
Methods
Two-step total etch adhesives comprising UDMA (60 wt%) and 40 wt% of: TAAEA, TMAAEA (secondary, tertiary tri-acrylamides), BAAP, DEBAAP (secondary, tertiary di-acrylamides) or HEMA (mono-methacrylate - control) were formulated. Simulated composite restorations (n = 5) were tested after cyclic mechanical and biological (S. mutans biofilm) challenges. Gap formation before and after aging was assessed with SEM imaging. Micro-tensile bond strength (μTBS, n = 6) was assessed after seven-day incubation in water or S. mutans-containing culture medium. Collagen reinforcement was assessed with hydroxyproline assay (n = 10) and rheology (n = 3). Data were analyzed with one-way/two-way ANOVA/Tukey’s test (alpha=5%).
Results
Gap formation increased and bond strength decreased for all monomers after biofilm incubation (p < 0.001). Except for DEBAAP, secondary and tertiary di/tri-acrylamides showed lower occlusal gap width values, but no significant differences overall gap length compared to HEMA. μTBS increased for tri-acrylamides compared with HEMA. Samples treated with multi-acrylamides had lower concentration of hydroxyproline (by-product of collagen degradation) (p < 0.001), except for DEBAAP, which showed values close to HEMA (p > 0.05). Dentin shear modulus increased for all acrylamides after 72 h, especially TMAAEA.
Significance
In general, multi-acrylamides promote collagen reinforcement, leading to reduced gap formation, and stabilize the bond strength under physiological conditions.
{"title":"Multi-acrylamides improve bond stability through collagen reinforcement under physiological conditions","authors":"Lincoln Borges , Matthew Logan , Samuel Weber , Steven Lewis , Clark Fang , Lourenço Correr-Sobrinho , Carmem Pfeifer","doi":"10.1016/j.dental.2024.05.002","DOIUrl":"10.1016/j.dental.2024.05.002","url":null,"abstract":"<div><h3>Objectives</h3><p>Acrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the hypothesis that hydrogen bonding reinforcement of the collagen network (with secondary or tertiary acrylamides), as well as degree of crosslinking of the polymer network (with di- or tri-functional acrylamides), can be two of the factors at play.</p></div><div><h3>Methods</h3><p>Two-step total etch adhesives comprising UDMA (60 wt%) and 40 wt% of: TAAEA, TMAAEA (secondary, tertiary tri-acrylamides), BAAP, DEBAAP (secondary, tertiary di-acrylamides) or HEMA (mono-methacrylate - control) were formulated. Simulated composite restorations (n = 5) were tested after cyclic mechanical and biological (<em>S. mutans</em> biofilm) challenges. Gap formation before and after aging was assessed with SEM imaging. Micro-tensile bond strength (μTBS, n = 6) was assessed after seven-day incubation in water or <em>S. mutans</em>-containing culture medium. Collagen reinforcement was assessed with hydroxyproline assay (n = 10) and rheology (n = 3). Data were analyzed with one-way/two-way ANOVA/Tukey’s test (alpha=5%).</p></div><div><h3>Results</h3><p>Gap formation increased and bond strength decreased for all monomers after biofilm incubation (p < 0.001). Except for DEBAAP, secondary and tertiary di/tri-acrylamides showed lower occlusal gap width values, but no significant differences overall gap length compared to HEMA. μTBS increased for tri-acrylamides compared with HEMA. Samples treated with multi-acrylamides had lower concentration of hydroxyproline (by-product of collagen degradation) (p < 0.001), except for DEBAAP, which showed values close to HEMA (p > 0.05). Dentin shear modulus increased for all acrylamides after 72 h, especially TMAAEA.</p></div><div><h3>Significance</h3><p>In general, multi-acrylamides promote collagen reinforcement, leading to reduced gap formation, and stabilize the bond strength under physiological conditions.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140903845","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}
Pub Date : 2024-06-01DOI: 10.1016/j.dental.2024.05.003
Wei-Chi Chen , Shu-Fen Chuang , Po-Chun Tseng , Ting-Weng Lai , Terry Yuan-Fang Chen , Yung-Nien Sun
Objective
To investigate the feasibility of optical coherence tomography (OCT)-based digital image correlation (DIC) analysis and to identify the experimental parameters for measurements of polymerization shrinkage.
Methods
Class I cavities were prepared on bovine incisors and filled with Filtek Z350XT Flowable (Z350F). One OCT image of the polymerized restoration was processed to generate virtually displaced images. In addition, the tooth specimen was physically moved under OCT scanning. A DIC software analyzed these virtual and physical transformation sets and assessed the effects of subset sizes on accuracy. The refractive index of unpolymerized and polymerized Z350F was measured via OCT images. Finally, different particles (70–80 µm glass beads, 150–212 µm glass beads, and 75–150 µm zirconia powder) were added to Z350F to inspect the analyzing quality.
Results
The analyses revealed a high correlation (>99.99%) for virtual movements within 131 pixels (639 µm) and low errors (<5.21%) within a 10-µm physical movement. A subset size of 51 × 51 pixels demonstrated the convergence of correlation coefficients and calculation time. The refractive index of Z350F did not change significantly after polymerization. Adding glass beads or zirconia particles caused light reflection or shielding in OCT images, whereas blank Z350F produced the best DIC analysis results.
Significance
The OCT-based DIC analysis with the experimental conditions is feasible in measuring polymerization shrinkage of RBC restorations. The subset size in the DIC analysis should be identified to optimize the analysis conditions and results. Uses of hyper- or hypo-reflective particles is not recommended in this method.
目的:研究基于光学相干断层扫描(OCT)的数字图像相关性分析的可行性,并确定聚合收缩测量的实验参数:研究基于光学相干断层扫描(OCT)的数字图像相关性(DIC)分析的可行性,并确定测量聚合收缩率的实验参数:在牛门牙上制备 I 类龋洞,用 Filtek Z350XT Flowable (Z350F) 填充。对聚合修复体的一张 OCT 图像进行处理,生成虚拟位移图像。此外,还在 OCT 扫描下移动牙齿样本。DIC 软件分析了这些虚拟和物理转换集,并评估了子集大小对准确性的影响。通过 OCT 图像测量了未聚合和聚合 Z350F 的折射率。最后,在 Z350F 中加入了不同的颗粒(70-80 微米的玻璃珠、150-212 微米的玻璃珠和 75-150 微米的氧化锆粉末),以检测分析质量:分析结果显示,131 像素(639 微米)范围内的虚拟移动具有较高的相关性(>99.99%),误差较小(显著性):在实验条件下,基于 OCT 的 DIC 分析可用于测量 RBC 修复体的聚合收缩。应确定 DIC 分析中的子集大小,以优化分析条件和结果。此方法不建议使用高反射或低反射颗粒。
{"title":"Assessments of polymerization shrinkage by optical coherence tomography-based digital image correlation analysis—Part I: Parameter identification","authors":"Wei-Chi Chen , Shu-Fen Chuang , Po-Chun Tseng , Ting-Weng Lai , Terry Yuan-Fang Chen , Yung-Nien Sun","doi":"10.1016/j.dental.2024.05.003","DOIUrl":"10.1016/j.dental.2024.05.003","url":null,"abstract":"<div><h3>Objective</h3><p>To investigate the feasibility of optical coherence tomography (OCT)-based digital image correlation (DIC) analysis and to identify the experimental parameters for measurements of polymerization shrinkage.</p></div><div><h3>Methods</h3><p>Class I cavities were prepared on bovine incisors and filled with Filtek Z350XT Flowable (Z350F). One OCT image of the polymerized restoration was processed to generate virtually displaced images. In addition, the tooth specimen was physically moved under OCT scanning. A DIC software analyzed these virtual and physical transformation sets and assessed the effects of subset sizes on accuracy. The refractive index of unpolymerized and polymerized Z350F was measured via OCT images. Finally, different particles (70–80 µm glass beads, 150–212 µm glass beads, and 75–150 µm zirconia powder) were added to Z350F to inspect the analyzing quality.</p></div><div><h3>Results</h3><p>The analyses revealed a high correlation (>99.99%) for virtual movements within 131 pixels (639 µm) and low errors (<5.21%) within a 10-µm physical movement. A subset size of 51 × 51 pixels demonstrated the convergence of correlation coefficients and calculation time. The refractive index of Z350F did not change significantly after polymerization. Adding glass beads or zirconia particles caused light reflection or shielding in OCT images, whereas blank Z350F produced the best DIC analysis results.</p></div><div><h3>Significance</h3><p>The OCT-based DIC analysis with the experimental conditions is feasible in measuring polymerization shrinkage of RBC restorations. The subset size in the DIC analysis should be identified to optimize the analysis conditions and results. Uses of hyper- or hypo-reflective particles is not recommended in this method.</p></div>","PeriodicalId":298,"journal":{"name":"Dental Materials","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140903842","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}