Introduction: The purpose of this study was to compare the changes in foot at different sole-ground contact angles during forefoot running. This study tried to help forefoot runners better control and improve their technical movements by comparing different sole-ground contact angles. Methods: A male participant of Chinese ethnicity was enlisted for the present study, with a recorded age of 25 years, a height of 183 cm, and a body weight of 80 kg. This study focused on forefoot strike patterns through FE analysis. Results: It can be seen that the peak von Mises stress of M1-5 (Metatarsal) of a (Contact angle: 9.54) is greater than that of b (Contact angle: 7.58) and c (Contact angle: 5.62) in the three cases. On the contrary, the peak von Mises stress of MC (Medial Cuneiform), IC (Intermediate Cuneiform), LC (Lateral Cuneiform), C (Cuboid), N (Navicular), T (Tarsal) in three different cases is opposite, and the peak von Mises stress of c is greater than that of a and b. The peak von Mises stress of b is between a and c. Conclusion: This study found that a reduced sole-ground contact angle may reduce metatarsal stress fractures. Further, a small sole-ground contact angle may not increase ankle joint injury risk during forefoot running. Hence, given the specialized nature of the running shoes designed for forefoot runners, it is plausible that this study may offer novel insights to guide their athletic pursuits.

BACKGROUND: The prevalence of adults with partially dental arches is expected to be more than imagined and patients requiring replacement of missing teeth are slowly increasing in number too. Removable partial dentures are known to provide for substantial replacement for the missing teeth with also added advantages when compared to fixed or implant prosthesis, mainly in elderly patients. Denture base material performance and durability are greatly influenced by wettability and water contact angle. In the case of dentures; adequate moisture distribution is necessary to ensure excellent wettability which has an influence on comfort and oral health. The purpose of conducting this study was to find out whether the advancements made using PEEK (Polyether ether ketone) would prove to be more beneficial than the current upgrades in the current material spectrum.
METHODS: This study was performed under in vitro conditions. All the fabrication and processing was done only by one operator. The materials used were divided into three groups each comprising 20 samples. Group A was modified polymethylmethacrylate (Bredent Polyan), Group B was polyoxymethylene acetal resin (Biodentaplast) and Group C was PEEK. An Ossila Goniometer was used to measure the contact angle. The three types of liquids used for the testing included distilled water, natural saliva and mouth wetting solution (Wet Mouth Liquid, ICPA India). Human saliva was collected from an individual with no medical conditions and normal salivary secretion.
RESULTS: The data was analyzed using One-way ANOVA test and a pairwise comparison using the Post Hoc Tukey\'s Honest Significant Difference. Table 1 consists of the mean water contact angles of the denture base materials and mean contact angles of various denture base materials. In saliva, mouth wetting solution and distilled water, the highest mean and least mean contact angle was seen in Polyan and Biodentaplast respectively. A signicant difference was seen between PEEK and Polyan and Biodentaplast and Polyan on further comparison.
CONCLUSIONS: From the resources and the materials at our disposal, it could be concluded that Polyan, Biodentaplast and PEEK and could be used as viable options in cast partial denture framework.

In this study, the surface laser treatment of a new type of dental biomaterial, a Ti-graphite composite, prepared by low-temperature powder metallurgy, was investigated. Different levels of output laser power and the scanning speed of the fiber nanosecond laser with a wavelength of 1064 nm and argon as a shielding gas were used in this experiment. The surface integrity of the machined surfaces was evaluated to identify the potential for the dental implant\'s early osseointegration process, including surface roughness parameter documentation by contact and non-contact methods, surface morphology assessment by scanning electron microscopy, and surface wettability estimation using the sessile drop technique. The obtained results showed that the surface roughness parameters attributed to high osseointegration relevance (Rsk, Rku, and Rsm) were not significantly influenced by laser power, and on the other hand, the scanning speed seems to have the most prevalent effect on surface roughness when exhibiting statistical differences in all evaluated profile roughness parameters except Rvk. The obtained laser-modified surfaces were hydrophilic, with a contact angle in the range of 62.3° to 83.2°.

The chitosan is fixed in an amide group of activated carboxyl groups and biological primary amino groups of nonwoven PET for antibacterial properties. Uncoated materials have fewer wetting properties and are less biocompatible. The objectives of the study were to evaluate surface chemical compositions and biocompatibility, antibacterial, and hydrophilic properties of polyester fabrics grafted with chitosan oligomers and after being activated by atmospheric pressure plasmas. A 2% 14.8 mg/cm2 uncolored PET woven fabric was dissolved in chitosan solution. Atmospheric pressure plasmas were used to activate polyester fabrics grafted with chitosan oligomers on both sides. Cell proliferation assay was performed for the biocompatibility study. The American Association of Textile Chemists and Colorists method was used to measure the width of the antibacterial zone and the Japanese Industrial Standard was used to count the number of bacterial colonies. Chitosan-coated and -activated uncolored PET woven fabric showed fewer percentage free carbon (p < 0.0001), higher percentage free oxygen to free carbon ratio (p < 0.0001), higher percentage free nitrogen to free carbon ratio (p = 0.0453), and higher percentage free oxygen plus free nitrogen to free carbon ratio (p < 0.0001) than untreated PET woven fabric. The dynamic contact angle of a water droplet and the wicking time were shorter for chitosan-coated and -activated uncolored PET woven fabric than untreated PET weaved fabric (p < 0.0001 for all). Chitosan coating leads to PET woven fabric being higher biocompatible, wettable, and antibacterial than untreated PET woven fabric.

The surface area determination has a vital role in measuring the properties of liquid and solid substances. Fluoride is a potent remineralizing agent of the teeth. The surface area is measured using a goniometer. The main aim of this study is to estimate the wettability of topical fluoride gel on the anterior and posterior teeth surfaces. Topical acidulated phosphate fluoride (APF) gel was taken in small quantities. Anterior and posterior teeth were collected, and their superficial unaltered enamel sections were used as the surface where the contact angle (CA) is determined. The surface wettability is determined using Ossila goniometer to measure CA. Each stage was mounted on a mechanical stage of the goniometer. A calibrated microsyringe was used to dispense drops of the APF gel over the surface of the specimen Group A (anterior tooth cut section) and Group B (posterior tooth cut section). This procedure is repeated for all specimen samples. The mean of CAs of the anterior teeth (88.41°) was greater when compared with the mean of posterior teeth (80.36°) CA. P value found using the paired t-test of SPSS software is found to be 0.271 (>0.05), hence statistically not significant. The greater the CA, the lower is the degree of wettability on the teeth surfaces. The mean CA of the topical fluoride APF gel on the anterior tooth surface is greater when compared to the posterior tooth surface. This signifies that greater wettability is seen on posterior tooth surfaces.

OBJECTIVE: To determine if there are any differences in surface characteristics (surface roughness and contact angle) among different CAD/CAM materials indicated for fabricating implant-supported restorations, following all the material preparation protocols provided by the manufacturer.
METHODS: One-hundred forty-four specimens were divided into six groups: RBC (resin-based composite), PMMA (polymethyl methacrylate), PEEK (polyether ether ketone), ZP (zirconia polished), ZG (zirconia glazed) and CoCr4 (CoCr4 alloy). The experimental part included surface roughness (SR) and contact angle of water (WCA) analyses, fulfilled with Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) view of surface topography. The data were analyzed using Kruskal-Wallis test with a Dunn\'s post hoc analysis, the correlation between measurements was tested using Spearman\'s rank correlation coefficient and all data were presented as mean ± SD.
RESULTS: ZG specimens were significantly rougher compared to other groups (p ≤ 0.05). The WCA measurements revealed significantly lower mean values in ZG group (p ≤ 0.05), contrary to PEEK and CoCr4 , where significantly higher mean values were observed, compared to other groups (p ≤ 0.05). There exist a moderate negative correlation between the SR and WCA (ρ = -0.41). AFM 3D and SEM 2D images presented more or less heterogeneous surface of all materials.
CONCLUSIONS: There were statistically significant differences in surface roughness and contact angle among tested material groups. Moderate negative correlation was found between surface roughness and contact angle of tested material groups.
CONCLUSIONS: The study gives us a better understanding of influence of physicochemical characteristics of investigated materials on their surface properties and provides useful knowledge for future researches in a view of material\'s behavior under in vivo conditions, when it comes to a question of features related to surface quality, such as microbial adhesion, corrosion, wear, biocompatibility and esthetics.

Surfactant can improve the wettability of water to coal, which is beneficial to reduce the production of coal dust in coal seam water injection. Through the measurement and calculation of contact angle and its decay rate, the wettability differences of SDS (C12H25OSO3Na), AES (C14H29O5NaS), OP-10 (C18H30O10), and JFC (RO(CH2CH2O)nH) to anthracite were compared. In addition, the wetting modification effect and infiltration rate of anthracite by water, AES, and OP-10 were studied by infrared spectroscopy and complex impedance monitoring of coal pillar immersion process. The results show that when the concentration of surfactant is 0.1%, the contact angle decay time of OP-10 is very short, and the contact angle decay rate is as high as 19°/s. The decay rate can more obviously reflect the wettability difference of surfactants. And the wetting modification effect of OP-10 on anthracite is stronger than that of AES, and the peaks of oxygen-containing functional groups such as carboxyl and hydroxyl groups are stronger. Furthermore, the capillary force between OP-10 and anthracite is much larger than that of water, which shows the characteristics of fast water absorption and wide distribution in the infiltration experiment of columnar coal. The results of complex impedance measurement indicate that the impedance decay rate of coal is well correlated with capillary rise factor FC, contact angle decay rate, and contact angle. It is hoped that the research results can provide help for coal seam water injection and dust prevention.

The aim of the present study was to understand the mechanism of lethality associated with high dose inhalation of a low-density hydrophobic surface-treated SAS observed in some acute inhalation studies. It was demonstrated that physical obstruction of the upper respiratory tract (nasal cavities) caused the effects observed. Hydrophobic surface-treated SAS was inhaled (flow-past, nose-only) by six Wistar rats (three males and three females) in an acute toxicity study at a concentration of ~500 mg/m3 for an intended 4-hr exposure. Under the conditions of the test set-up, the concentration applied was found to be the highest that can be delivered to the test animal port without significant alteration of the aerosol size distribution over time. None of the test- material-exposed animals survived the planned observation time of 4 h; three animals died between 2 3 4 h after starting exposure and cessation of exposure at 3 1 4 h, two died after transfer to their cages and the remaining animal was sacrificed due to its poor condition and welfare considerations. Histology accomplished by energy dispersive X-ray (EDX) analysis demonstrated that test material particles agglomerated and formed a gel-like substrate that ultimately blocked the upper respiratory airways, which proved fatal for the rat as an obligatory nose breather. This observation is in line with the findings reported by Hofmann et al. showing a correlation between lethality and hydrophobicity determined by contact angle measurement. The aerosol characterizations associated with this study are provided in detail by Wessely et al.

Self-etch adhesive systems have the advantages of simple operating steps and low technique sensitivity. However, some deficiencies of self-etch adhesive result that the immediate bonding strength between self-etch adhesive and dentine is not so high. Non-thermal atmospheric pressure plasma (NTAPP) can be used for surface modification. Previous studies of our research group have proven that NTAPP can improve bonding durability between dentine and etch-and-rinse adhesive. However, it is still unknown whether NTAPP can improve bonding strength between dentine and self-etch adhesive. The study observed the contact angle on dentine surface, the adhesive permeability and MTBS. The study proved that NTAPP can improve dentine surface wettability, clear up smear layer, and enhanced the self-etch adhesive permeability in dentine bonding interface. In conclusion, NTAPP could improve the bonding strength between dentine and self-etch adhesive systems. The most optimum treating time was 15 s.

Research into materials for medical application draws inspiration from naturally occurring or synthesized surfaces, just like many other research directions. For medical application of materials, particular attention has to be paid to biocompatibility, osseointegration, and bacterial adhesion behavior. To understand their properties and behavior, experimental studies with natural materials such as teeth are strongly required. The results, however, may be highly case-dependent because natural surfaces have the disadvantage of being subject to wide variations, for instance in their chemical composition, structure, morphology, roughness, and porosity. A synthetic surface which mimics enamel in its performance with respect to bacterial adhesion and biocompatibility would, therefore, facilitate systematic studies much better. In this study, we discuss the possibility of using hydroxyapatite (HAp) pellets to simulate the surfaces of teeth and show the possibility and limitations of using a model surface. We performed single-cell force spectroscopy with single Staphylococcus aureus cells to measure adhesion-related parameters such as adhesion force and rupture length of cell wall proteins binding to HAp and enamel. We also examine the influence of blood plasma and saliva on the adhesion properties of S. aureus. The results of these measurements are matched to water wettability, elemental composition of the samples, and the change in the macromolecules adsorbed over time on the surface. We found that the adhesion properties of S. aureus were similar on HAp and enamel samples under all conditions: Significant decreases in adhesion strength were found equally in the presence of saliva or blood plasma on both surfaces. We therefore conclude that HAp pellets are a good alternative for natural dental material. This is especially true when slight variations in the physicochemical properties of the natural materials may affect the experimental series.