Explore the vast range of titles available.

Thanks to the continuous development of light-curing resin composites it is now possible to print permanent single-tooth restorations. The purpose of this study was to compare resin composites for milling -Gandio Blocks (GR), Brilliant Crios (CR) and Enamic (EN) with resin composite for 3D printing—Varseo Smile Crown plus (VSC). Three-point bending was used to measure flexural strength (σf) and flexural modulus (Ef). The microhardness was measured using a Vickers method, while fractographic, microstructural, texture and fractal dimension (FD) analyses were performed using SEM, optical microscope and picture analysis methods. The values of σf ranged from 118.96 (±2.81) MPa for EN to 186.02 (±10.49) MPa for GR, and the values of Ef ranged from 4.37 (±0.8) GPa for VSC to 28.55 (±0.34) GPa for EN. HV01 ranged from 25.8 (±0.7) for VSC to 273.42 (±27.11) for EN. The filler content ranged from 19–24 vol. % for VSC to 70–80 vol. % for GR and EN. The observed fractures are typical for brittle materials. The correlation between FD of materials microstructure and Ef was observed. σf of the printed resin depends on layers orientation and is significantly lower than σf of GR and CR. Ef of the printed material is significantly lower than Ef of blocks for milling.

Accurate identification of growth and development stages is critical for orthodontic diagnosis, treatment planning, and post-treatment retention. While hand–wrist radiographs are the traditional gold standard, the associated radiation exposure necessitates alternative imaging methods. Lateral cephalometric radiographs, particularly the maturation stages of the second, third, and fourth cervical vertebrae (C2, C3, and C4), have emerged as a promising alternative. However, the nonlinear dynamics of these images pose significant challenges for reliable detection. This study presents a novel approach that integrates chaotic functional connectivity (FC) matrices and fractal dimension analysis to address these challenges. The fractal dimensions of C2, C3, and C4 vertebrae were calculated from 945 lateral cephalometric radiographs using three methods: fast Fourier transform (FFT), box counting, and a pre-processed FFT variant. These results were used to construct chaotic FC matrices based on correlations between the calculated fractal dimensions. To effectively model the nonlinear dynamics, chaotic maps were generated, representing a significant advance over traditional methods. Feature selection was performed using a wrapper-based approach combining k-nearest neighbors (kNN) and the Puma optimization algorithm, which efficiently handles the chaotic and computationally complex nature of cervical vertebrae images. This selection minimized the number of features while maintaining high classification performance. The resulting AI-driven model was validated with 10-fold cross-validation and demonstrated high accuracy in identifying growth stages. Our results highlight the effectiveness of integrating chaotic FC matrices and AI in orthodontic practice. The proposed model, with its low computational complexity, successfully handles the nonlinear dynamics in C2, C3, and C4 vertebral images, enabling accurate detection of growth and developmental stages. This work represents a significant step in the detection of growth and development stages and provides a practical and effective solution for future orthodontic diagnosis.

Prefabricated Ultra-High-Performance Concrete (UHPC) and cast-in-place Normal Concrete (NC) composite members are increasingly used in bridge engineering because they combine high performance with cost-effectiveness. The bond at the UHPC-NC interface is critical as it directly impacts the composite structure’s safety. This study employed 3D laser scanning acquired the UHPC substrate geometry, utilized fractal dimension analysis to quantify the interface roughness, and adopted the slant shear test to evaluate the effects of retarder application mass and hydration delay duration on roughness and bond strength. The research results indicate that the failure modes of UHPC-NC specimens can be categorized into interface shear failure and NC splitting tensile failure. With the extension of hydration delay duration, both the interface roughness and bond strength show a decreasing trend. The influence of retarder dosage on interface roughness and bond strength exhibits a threshold effect. This study also confirms the effectiveness of fractal dimension as a quantitative tool for characterizing the macroscopic roughness features of the bonding interface. The findings of this paper provide a solid theoretical basis and quantitative support for optimizing key process parameters such as retarder dosage and precisely controlling hydration delay duration, offering significant engineering guidance for enhancing the interface bonding performance of UHPC-NC composite structures.

A surface profilometry technique was used to characterize the surfaces of paper products. A stylus-contact type profilometer capable of simultaneously generating both surface roughness- and friction-profiles was used. As a stylus for the profilometer, a conical shape whose tip was rounded to have a 0.5 mm curvature radius was designed and successfully employed in both printing & writing (P&W) papers and hygiene papers such as bathroom tissues and kitchen towel. From the profiles, the mean absolute deviation (MAD) from the averages, i.e., R-MAD from the roughness average and F-MAD from the average coefficient of friction, were suggested as the new surface characterization parameters. To elucidate the surface roughness profiles by fractal dimension analysis, the variogram method was applied to get the fractal dimensions of the paper products. Generally, the value of the fractal dimension increased as the surface roughness increased. The surface profilometry technique with the fractal dimension analysis with the variogram method looks promising to gain additional insight on the surface characteristics of paper products.

Laser-induced periodic surface structures (LIPSS) are the sub-wavelength periodic nanostructures generated by the femtosecond laser. Implant topography and its nanostructural changes can be important for biomedical applications. In order to compare the surface topography of different implants, appropriate mathematical and physical descriptive methods should be provided. The aim of the study was to evaluate the experimental LIPSS-based—Low Spatial Frequency LIPSS (LSFL) dental implant surfaces. Novel methods of surface analysis, such as Fractal Dimension Analysis and Texture Analysis, were compared to the standard surface roughness evaluation. Secondary, cell viability, and attachment tests were applied in order to evaluate the biological properties of the new titanium surface and to compare their correlation with the physical properties of the new surfaces. A Normal Human Dermal Fibroblast (NHDF) cytotoxicity test did not show an impact on the vitality of the cells. Our study has shown that the laser LIPSS implant surface modifications significantly improved the cell adhesion to the tested surfaces. We observed a strong correlation of adhesion and the growth of cells on the tested surface, with an increase in implant surface roughness with the best results for the moderately rough (2 μm) surfaces. Texture and fractal dimension analyses are promising methods to evaluate dental implants with complex geometry.

Orthodontic removable appliances made of transparent thermoplastic materials—aligners—are becoming increasingly popular in contemporary orthodontic practice. It is important for the clinician to fully understand the mechanical properties and behavior of the appliance used. Because of that, the aim of our study was to investigate the changes in aligner surface after immersion in Coca-Cola and orange juice. For surface evaluation, fractal analysis, texture analysis, and wetting angle measurement were performed. Statistically significant changes were found between some of the groups in the fractal dimension analysis. In texture analysis, all but one intergroup comparison showed statistically significant differences. For wetting angle assessment, statistically significant differences were found. These were, however, more numerous when assessing glycol droplets, rather than water droplets. Fractal dimension analysis confirmed a correlation between the intensity of changes in the aligner surface with immersion time in the liquids assessed. Texture analysis showed a high sensitivity to the changes in aligner surface. It failed, however, to reveal changes relative to immersion time. Wetting angle analysis revealed aligner surface degradation for Coca-Cola. It did not, however, prove the dependence of the intensity of this degradation as a function of time. Both Coca-Cola and orange juice can cause aligner surface degradation.

Biocompatibility is defined as “the ability of a biomaterial, prosthesis, or medical device to perform with an appropriate host response in a specific application”. Biocompatibility is especially important for restorative dentists as they use materials that remain in close contact with living tissues for a long time. The research material involves six types of cement used frequently in the subgingival region: Ketac Fil Plus (3M ESPE, Germany), Riva Self Cure (SDI, Australia) (Glass Ionomer Cements), Breeze (Pentron Clinical, USA) (Resin-based Cement), Adhesor Carbofine (Pentron, Czech Republic), Harvard Polycarboxylat Cement (Harvard Dental, Great Britain) (Zinc polycarboxylate types of cement) and Agatos S (Chema-Elektromet, Poland) (Zinc Phosphate Cement). Texture and fractal dimension analysis was applied. An evaluation of cytotoxicity and cell adhesion was carried out. The fractal dimension of Breeze (Pentron Clinical, USA) differed in each of the tested types of cement. Adhesor Carbofine (Pentron, Czech Republic) cytotoxicity was rated 4 on a 0–4 scale. The Ketac Fil Plus (3M ESPE, Germany) and Riva Self Cure (SDI, Australia) cements showed the most favorable conditions for the adhesion of fibroblasts, despite statistically significant differences in the fractal dimension of their surfaces.

In this study, we present the fractal characteristics of the spatio-temporal sequence for seismic activity in the circum-Pacific seismic belt and vicinity regions, which is one of the most active seismic zones worldwide. We select the seismic dataset with magnitude M ≥ 4.4 in the circum-Pacific seismic belt region and its vicinity from 1900–2015 as the objects. Based on the methods of capacity dimension and information dimension, using ln ( 1 / δ ) – ln N ( δ ) of the relationship to evaluate and explain, the results show that (1) in the circum-Pacific seismic belt and the surrounding areas, for the seismic activity with magnitude M ≥ 4.4 , the time series dimension is 0.63, the spatial distribution dimension is 0.52 and they have fractal structure. (2) For the earthquakes with M ≥ 7.0 , the time series dimension increases greatly, which indicates that the cluster characteristics in time is greatly reduced. And the earthquakes with magnitude 7.0 ≥ M ≥ 4.4 have significant impact on the characterized by clustering in time in the study region. (3) There is significant fractal structure at spatio-temporal distribution of earthquakes in the circum-Pacific seismic belt. It reveals the tectonic movements keep continuous, obvious anisotropism characteristic of geological structure and the distribution of surface stress field is spatio-temporal heterogeneity in the study area.

Single nucleotide polymorphisms (SNPs) play a crucial role in regulating vitamin D, parathyroid hormone (PTH), and calcitonin concentrations, which are involved in bone health. Some reports suggested that fractal analysis is useful in the morphometric analysis of the mandible trabecular bone in panoramic radiographs. Therefore, we investigated if SNPs in genes that influence vitamin D, calcitonin, and PTH levels are involved in condylar bone quality during the active growing phase of the mandible. Fractal dimension was obtained from the condyle region of interest (ROI) using panoramic radiographs and used to measure the complexity and the microarchitecture of the bone. Fractal dimension using the box‐counting algorithm was then calculated. In order to avoid information bias, a script to automate the commands in the software ImageJ was generated to ensure consistency and minimize the potential for human error during the data analysis process. SNPs in vitamin D receptor ( VDR ), cytochrome P450 family 27 subfamily B member 1 ( CYP27B1 ), cytochrome P450 family 24 subfamily A member 1 ( CYP24A1 ), vitamin D binding protein ( VDBP ), SEC23 homolog A ( SEC23A ), calcitonin receptor ( CALCR ), and parathyroid hormone ( PTH ) were analyzed. DNA extracted from saliva was used for genotyping analysis of VDR (rs7975232, rs2228570, and rs1544410), CYP27B1 (rs4646536), CYP24A1 (rs927650), VDBP (rs4588), SEC23A (rs8018720), CALCR (rs1801197), and PTH (rs6256, rs307247, and rs694). A statistical analysis was performed with an alpha error tolerance of 5%. A total of 100 children were included; 50 (50%) were boys and the age ranged from 5 to 14 years old. Fractal dimensions were compared among genotypes. The GT (mean = 1.20 and standard error = 0.03, p = 0.024) and TT genotypes (mean = 1.16 and standard error = 0.06, p = 0.047) in the gene VDBP (rs4588) presented lower fractal dimension. The GG genotype in SEC23A (rs8018720) (mean = 1.34 and standard error = 0.03, p = 0.011) and the TC genotype in PTH (rs694) showed an increased fractal dimension (mean = 1.29 and standard error = 0.03, p = 0.020). In conclusion, SNPs in VDBP, SEC23A, and PTH encoding genes are associated with mandibular condylar trabecular bone structure in children.

Chemical composition and physical parameters of the implant surface, such as roughness, regulate the cellular response leading to implant bone osseointegration. Possible implant surface modifications include anodization or the plasma electrolytic oxidation (PEO) treatment process that produces a thick and dense oxide coating superior to normal anodic oxidation. Experimental modifications with Plasma Electrolytic Oxidation (PEO) titanium and titanium alloy Ti6Al4V plates and PEO additionally treated with low-pressure oxygen plasma (PEO-S) were used in this study to evaluate their physical and chemical properties. Cytotoxicity of experimental titanium samples as well as cell adhesion to their surface were assessed using normal human dermal fibroblasts (NHDF) or L929 cell line. Moreover, the surface roughness, fractal dimension analysis, and texture analysis were calculated. Samples after surface treatment have substantially improved properties compared to the reference SLA (sandblasted and acid-etched) surface. The surface roughness (Sa) was 0.59–2.38 µm, and none of the tested surfaces had cytotoxic effect on NHDF and L929 cell lines. A greater cell growth of NHDF was observed on the tested PEO and PEO-S samples compared to reference SLA sample titanium.