Compressive Strength Testing of Glass-Fibre-Reinforced Tooth Crown Tissues After Endodontic Treatment.

The objective of this study was to compare the effects of using short and continuous fibres for repairing compression-induced tooth crown damage. Human teeth were used for the study. They were upper medial incisors and maxillary first premolars lost due to periodontal causes. The teeth were divided into two groups with Hahnenkratt and short glass fibres. Teeth compressive strength tests were carried out. Then micro-CT imaging of the teeth and their fractures obtained after compression was performed. The teeth restored with Hahnenkratt's glass fibre posts showed higher compressive strength than the teeth restored using the EverX Posterior material. The tooth's most weakened and sensitive point after endodontic treatment was the cervical area of the tooth. All cracks were parallel to the root canal.

Microcapsules in Fiber Metal Laminates for Self-Healing at the Interface between Magnesium and Carbon Fiber-Reinforced Epoxy.

The paper presents issues regarding self-healing isophorone diisocyanate (IPDI) microcapsules applied in fiber metal laminates (FMLs) based on magnesium AZ31 and a carbon-reinforced polymer composite. The aim of this work is to analyze the morphology of the produced PU/PUa microcapsules containing IPDI and their behavior in a self-healing layer in FMLs. By means of SEM, it was confirmed that the microcapsules (MCs) had a narrow size distribution. Therefore, the developed MCs, having sizes ranging from 10 to 35 µm, might contribute to an improved self-healing coating, which benefits from the advantages of both small and larger-sized MCs. The positive result of the work is that there is a possibility to improve the properties of FMLs with added MCs, i.e., in corrosion and mechanical phenomena.

Programming Effect of the Parental Obesity on the Skeletal System of Offspring at Weaning Day.

Our study aimed to verify the hypothesis of the existence of a programming effect of parental obesity on the growth, development and mineralization of the skeletal system in female and male rat offspring on the day of weaning. The study began with the induction of obesity in female and male rats of the parental generation, using a high-energy diet (group F). Females and males of the control group received the standard diet (group S). After 90 days of dietary-induced obesity, the diet in group F was changed into the standard. Rats from groups F and S were mated to obtain offspring which stayed with their mothers until 21 days of age. Tibia was tested using dual-energy X-ray absorptiometry (DXA), peripheral quantitative computed tomography (pQCT), micro-computed tomography (µCT) and mechanical strength using the three-point bending test. Biochemical analysis of blood serum bone metabolism markers was performed. DXA analysis showed higher tibia bone mineral content (BMC) and area. pQCT measurements of cortical and trabecular tissue documented the increase of the volumetric bone mineral density and BMC of both bone compartments in offspring from the F group, while µCT of the trabecular tissue showed an increase in trabecular thickness and a decrease of its separation. Parental obesity, hence, exerts a programming influence on the development of the skeletal system of the offspring on the day of the weaning, which was reflected in the intensification of mineralization and increased bone strength.

Analysis of marginal integrity in dentistry composite fillings with flow layer under compression test.

Currently, composite materials dominate among the restorative materials used for direct aesthetic filling. Reinforcement of composites with glass fibers allows for the transfer of greater loads and better durability between the tooth tissue and the filling polymer. New approach to bonding liquid materials with composite with glass fillers is to introduce an additional protective barrier to load a higher force that is, compression test. So, the aim of the study was to analyze the structure of composite fillings, their integrity with tooth tissues and evaluation on the influence of the liquid composite layer on the strength of strength in the compression test. Moreover, the influence of thermal shocks on the bonding with the tooth tissues in the compression test was investigated. According to the results obtained in current research, using the flow composite as a combination with the fiber composite leads to a significant increase in mechanical properties, particularly in the compression test. HIGHLIGHTS: If flow-type composite fluid material are, the greater is strength of composite fillings. Glass fibers composite increase the mechanical strength.

Fracture Analysis and Shear Strength of Aluminum/CFRP and GFRP Adhesive Joint in Fiber Metal Laminates.

Fiber metal laminates (FMLs) were initially developed under the motivation of the aerospace industry. Generally, they consist of aluminum and high strength glass fiber in polymeric layers, but the new challenge is to apply them with a carbon fiber. Pretreatment of aluminum is the main factor responsible for the adhesion between metallic and polymeric layers. The shear strength test a very popular method in the experimental joint of two components. In this article, the main aim was to compare the surface pretreatment and configuration of fibers in FMLs based on aluminum with glass and carbon fibers. The decisive factor of strength in adhesive or cohesive failure is first the type of fibers, and second, the surface preparation.

The Durability of an Organic-Inorganic Sol-Gel Interlayer in Al-GFRP-CFRP Laminates in a Saline Environment.

The aim of the study was to assess the selected properties of a hybrid organic-inorganic silane sol-gel coating (HSG) used in hybrid fiber metal laminates (FML) in a corrosion environment. The HSG coating on the aluminum alloy was produced using 3M™ AC130-2 formulation consisting of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and tetra-n-propoxyzirconium (zirconium(IV) propoxide) (TPOZ). Laminates consisted of aluminum alloy AA2024-T3 sheets, with carbon fiber reinforced polymers (CFRPs) and a glass fiber reinforced metal-composite structure (GFRP). Potentiodynamic and polarization curve and impedance (EIS) tests were carried out on HSG at ambient temperatures after 1 h and 150 h of soaking. Neutral 0.5 M NaCl and 0.8 M NaCl solutions were used for open circuit potential (OCP) and potentiodynamic tests, and 0.5 NaCl was used for the EIS test. A neutral salt spray (NSS) test was applied to laminates with a 12 week exposure period. The results obtained revealed that the HSG coating did not provide sufficient protection against corrosion of the aluminum alloy in direct contact with an aggressive environment but was effective as an interlayer. Local aluminum sheet perforation did not lead to delamination at the metal-composite interface regardless of the type or configuration of the composite. This confirms the durability of HSG used in FMLs.

Interrelationships Between Morphometric, Densitometric, and Mechanical Properties of Teeth in 5-Month-Old Polish Merino Sheep.

Interrelationships between morphological, densitometric, and mechanical properties of deciduous mandibular teeth (incisors, canine, second premolar) were investigated. To perform morphometric, densitometric, and mechanical analyses, teeth were obtained from 5-month-old sheep. Measurements of mean volumetric tooth mineral density and total tooth volume were performed using quantitative computed tomography. Microcomputed tomography was used to measure total enamel volume, volumetric enamel mineral density, total dentin volume, and volumetric dentin mineral density. Maximum elastic strength and ultimate force of teeth were determined using 3-point bending and compression tests. Pearson correlation coefficients were determined between all investigated variables. Mutual dependence was observed between morphological and mechanical properties of the investigated teeth. The highest number of positive correlations of the investigated parameters was stated in first incisor indicating its superior predictive value of tooth quality and masticatory organ function in sheep. Positive correlations of the volumetric dentin mineral density in second premolar with final body weight may indicate predictive value of this parameter in relation with growth rate in sheep. Evaluation of deciduous tooth properties may prove helpful for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory organ function, leading to improved performance and economic efficiency of the flock.

Qualitative analysis of the margins of restorations made with different filling resins.

PURPOSE: In this study the comparative results obtained from examinations of two different restorative composites with different cavities filling method are presented. Micro-CT was used for the evaluation of the marginal integrity and quality of composite fillings in connection with microstructural investigations made by both optical and scanning electron microscopy. MATERIALS AND METHODS: The examinations of dental tooth filings in bulk-fill technique were based on micro-CT and microscopy observations. Two different restorative composites were selected for the study, namely SonicFill- bulk fill and conventional Filtek Z550. RESULTS: The experiment has shown that micro-CT screening analysis for identification of individual components of tooth and fillings systems gives a high quality of images. Thanks to that it was possible to analyze and identify the porosity in the fillings. But the microscopy analysis has shown more information about the internal structure and quality of bonding between composite and enamel/dentin. The SonicFill gives better quality and bonding to structure of teeth than Filtek. CONCLUSIONS: SonicFill's filling have more homogenous structure than Filtec. It has a greater share of reinforcement in the form of polygonal particles, in Filtek particles have a shape close to spherical. Sonic Fill gives a better adhesion to tooth. CLINICAL RELEVANCE: The evaluation of clinical relevance in this research is crucial to simplify the transfer of knowledge from research by materials engineering into practice in dentistry.

Morphometric, densitometric and mechanical properties of mandibular deciduous teeth in 5-month-old Polish Merino sheep.

BACKGROUND: Caries, enamel hypoplasia, molar incisor hipomineralization, amylogenesis imperfecta, dentine dysplasia, hypophosphatasia and other dental disorders lead to tooth mineralization disturbances and structural abnormalities, decreasing masticatory organ functions. Dental disorders in sheep can lead to premature slaughter before they have attained final stage of their reproductive life and induce economic loss due to high flock replacement costs. Growth rate, health status and meat quality of sheep depends on tooth properties and quality determining in large extent efficiency of the masticatory apparatus and initial food break up. Considering lack of basic anatomical and physiological data on teeth properties in sheep, the aim of the study was to evaluate morphometric, densitometric and mechanical traits of deciduous mandibular incisor, canine and the second premolar obtained at the slaughter age of 5 months of life. RESULTS: The obtained results have shown the highest values of weight, total tooth volume, enamel volume and dentine volume in second premolar. Morphometric and mechanical parameters of incisors reached the highest values in first incisor and decreased gradually in second and third incisor, and in canine. Densitometric measurements have not revealed significant differences of the volumetric tooth mineral density in hard dental tissues between the investigated teeth. CONCLUSIONS: In conclusion, proposed methodological approach is noninvasive since the deciduous teeth undergo physiological replacement with permanent teeth. Deciduous teeth can be easy collected for analyses from large animal population and may reflect mineral status and metabolism resulting from postnatal growth and development of the whole flock. In individual cases, evaluation of properties of deciduous teeth may serve for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory system functions.