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The digital teaching competence of university professors is of vital importance to improving the quality of higher education, and for the strategic positioning of public universities in our country. The purpose of this study is to find out the level of digital competence of Galician university professors, as well as to identify whether there are significant variable-based differences. To this end, a non-experimental design with a descriptive approach and hypothesis contrast is proposed. The sample studied is made up of a total of 610 teachers from the three public universities of Galicia (Spain), who responded to the DigCompEdu Check-In instrument adapted to the Spanish context (Cabero-Almenara & Palacios-Rodríguez, 2020). In general terms, the results show a medium-low level and the existence of significant differences depending on the age, recruitment profile and area of knowledge of the teaching staff. Specifically, the younger teaching and research staff, together with Social and Legal Sciences, have a higher level of competence, whereas tenured teaching and research staff have a lower level of competence with respect to contracted workers. Therefore, training plans should be developed which focus on teaching. Expert advice and personalized methodological support should shift the focus of the intervention radically from technology to teaching.

Hydraulic calcium silicate cements (HCSCs) are valuable for various dental procedures. However, several reports document inherent limitations and complaints about their high costs, hindering accessibility in low—and middle-income countries. This study aimed to characterize four low-cost HCSC prototypes to show their microstructure, composition, and fundamental physical properties. Four HCSC prototypes were formulated: 1- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate, 2- calcium silicate powder with 17.5 wt. % replacement of zirconium oxide, 3- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate and 2.5 wt. % of zirconium oxide and 4- calcium silicate powder with 10 wt. % replacement of calcium tungstate and 10 wt. % replacement of zirconium oxide. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to assess their microstructure and composition. Additionally, radiopacity, setting time, solubility, pH, and in vitro bioactivity were evaluated at different time points and contrasted with controls (Mineral trioxide aggregate –MTA Angelus- and Intermediate restorative material -IRM-). Their production cost was significantly lower than commercially available HCSCs. All prototypes exhibited a microstructure and composition comparable to MTA Angelus. All the prototypes exhibited radiopacity exceeding 3 mm of aluminum and shorter initial and final setting times than MTA Angelus. The solubility of some prototypes closely adhered to the ISO standard recommendation of 3% after 1 day, and all promoted an alkaline pH and the formation of calcium/phosphate precipitates. These promising findings suggest the potential clinical application of these prototypes. However, further research is necessary to evaluate their mechanical and biological properties for definitive clinical use.

Cellulose hydrogels derived from agave bagasse were formulated to promote the regeneration of gingival connective tissue in lagomorphs. Three treatment modalities were randomly implanted in the gingival diastema area in 16 rabbits. The general characteristics were analyzed and histopathological studies were carried out at 4, 8, 12, and 16 weeks. A chi-squared test was performed using IBM-SPSS version 25, indicating that cellulose hydrogels implanted in lagomorph’s gingival tissue showed the presence of greater angiogenesis and fibrogenesis at the four evaluation intervals during 16 consecutive weeks. The presence of inflammatory infiltrates had no significant impact. No significant changes were observed in body weight and water and food intake. This suggests that hydrogels contribute to the regeneration and/or repair of oral connective tissue, showing angiogenesis and fibrogenesis in 50 to 100% of rabbits tested with hydrogel cellulose membrane. Regarding angiogenesis, in the specimens where membranes were implanted, its presence predominated in all variants (50%), followed by diffuse angiogenesis (37.5%), and finally the absence of angiogenesis (12.5%).

Lithium niobate perovskite and silver nanoparticle-based nanocomposites (LNB:AgNPs) were explored for developing an electrochemical glucose sensor. The perovskite to silver nanoparticle ratios investigated were 4:1, 1:1, 1:2, 2:1, and 1:4. Among these, the 4:1 ratio, with the lowest silver content, demonstrated the most stable performance during glucose quantification via amperometry. The sensor’s response was evaluated measuring the current at a fixed potential of 0.7 V following the injection of 1 mM glucose with each addition. The calibration curve obtained from the recorded data exhibited a linear response within the 1 to 15 mM glucose concentration range, achieving a sensitivity of 2 μA/mM, a high correlation coefficient (R2 = 0.997), and a limit of detection (LOD) of 0.5 µM. The LNB4:1AgNP composite allowed taking advantage of the unique properties of both components in a balanced manner, maximizing the sensor performance in practical applications.

Hydrogels elaborated from Dasylirion spp. and enriched with grape seed extract (GSE) were investigated for tentative use in dental treatment. Cellulose-GSE hydrogels were elaborated with varying GSE contents from 10 to 50 wt%. The mechanical and physical properties, antimicrobial effect, biocompatibility, and in vitro cytotoxicity were studied. In all the cases, the presence of GSE affects the hydrogel’s mechanical properties. The elongation decreased from 12.67 mm for the hydrogel without GSE to 6.33 mm for the hydrogel with the highest GSE content. The tensile strength decrease was from 52.33 N/mm2 (for the samples without GSE) and went to 40 N/mm2 for the highest GSE content. Despite the adverse effects, hydrogels possess suitable properties for manipulation. In addition, all hydrogels exhibited excellent biocompatibility and no cytotoxicity, and the antibacterial performance was demonstrated against S. mutans, E. Faecalis, S. aureus, and P. aureginosa. Furthermore, the hydrogels with 30 wt% GSE inhibited more than 90% of the bacterial growth.

One of the main objectives in education is to increase the motivation of the students to achieve meaningful learning. The use of technologies in classrooms which students are familiarized with such as the smartphone or the tablet, is a way to achieve this goal. On the other hand, it has been proven that the inclusion of scenarios supported by games and competition enhance the active participation of students. Therefore, in this work we present the results of a study based on of the application Kahoot with students of secondary education, in the subjects of mathematics, biology & geology and physics & chemistry, during the academic year 2017/2018. This tool allows students to answer to on-line questionnaires created by the teacher, through mobile devices, and check their results in a few seconds as well as those of their classmates. The results obtained on the assessment of the tool by students, in terms of the benefits in the learning process, have been very positive and help us to examine the potential of the use of on-line questionnaires in the classrooms.

Background and objectives: The development of the oral microbiome begins in the prenatal stage. Breast milk contains antimicrobial proteins, microorganisms, metabolites, enzymes, and immunoglobulins, among others; therefore, differences have been noted in the type of microorganisms that colonize the oral cavity of children who are breastfed compared to those who are formula-fed. Our objective was to establish the relationship between breastfeeding, formula feeding, or mixed feeding (breastfeeding and formula) with the presence of S. mutans in a population of children under 6 months of age. Materials and Methods: The patients were recruited from the Child Care Center of Ciudad Juárez, Chihuahua, and from the pediatric dentistry postgraduate clinics of the Autonomous University of Ciudad Juárez; children exclusively fed maternally, with formula, and/or mixed were included. Those who had been fed within the previous hour were excluded. The sample was taken with a smear of the jugal groove using a sterile micro-brush. For the identification of Streptococcus mutans, a culture of Mitis Salivarius Agar (Millipore) was used. Results: 53.3% corresponded to females and 46.7% to males, 36.7% corresponded to maternal feeding, 23.3% corresponded to formula feeding, and 40% corresponded to mixed feeding. In 90% of the infants, the parents indicated that they did not perform oral hygiene. The CFU count showed that infants who were exclusively breastfed had an average of 9 × 10 CF/mL, formula-fed infants had an average of 78 × 10 CFU/mL, and those who had mixed feeding 21 × 10 CFU/mL. Conclusions: According to the results obtained, it was possible to corroborate that exclusive breastfeeding limits the colonization of Streptococcus mutans compared to those infants who receive formula or mixed feeding; these results could have a clinical impact on the dental health of infants by having a lower presence of one of the main etiological factors involved in dental caries and the type of microbiome established in the oral cavity.

Background: Motor and intellectual disabilities (MIDs) represent a great challenge for maintaining general health due to physical and cognitive limitations, particularly in the maintenance and preservation of oral health. Silver nanoparticles (AgNPs) have emerged as a promising therapeutic tool for bacterial control, including oral biofilms; however, knowledge of the bactericidal effectiveness of oral biofilms from patients with MIDs is insufficient. This study aims to determine the antimicrobial effect of AgNPs on different oral biofilms taken from patients with and without MIDs. Methods: Two sizes of AgNPs were prepared and characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Through consecutive sampling, biofilm samples were collected from 17 subjects with MIDs and 20 subjects without disorders. The antimicrobial effect was determined by obtaining the minimum inhibitory concentration (MIC) of AgNPs, and the identification and distribution of oral bacterial species were determined by polymerase chain reaction (PCR). Finally, correlations between sociodemographic characteristics and the antimicrobial levels of AgNPs were also explored. The values of the MIC results were analyzed with IBM-SPSS software (version25) using non-parametric tests for independent groups and correlations, with statistical significance being considered as p < 0.05. Results: Both sizes of AgNPs exhibited tight particle size distributions (smaller: 10.2 ± 0.7 nm; larger: 29.3 ± 2.3 nm) with zeta potential values (−35.0 ± 3.3 and −52.6 ± 8.5 mV, respectively) confirming the stability that resulted in little to no agglomeration of nanoparticles. Although both sizes of AgNPs had good antimicrobial activity in all oral biofilms, the smallest particles had the best antimicrobial effects on the oral biofilm samples from patients with and without MIDs, even better than chlorhexidine (CHX) (p < 0.05). Likewise, the patients with disabilities showed higher levels of antimicrobial sensitivity to AgNPs compared with CHX (p < 0.05). Although the microorganisms included in the biofilms of females had a statistically higher growth level, the AgNP antimicrobial effect was statistically similar in both genders (p > 0.05). The most frequent bacteria for all oral biofilms were S. mutans (100%), P. intermedia (91.6%), T. forsythia (75.0%), T. denticola (75.0%), P. gingivalis (66.6%), F. nucleatum (66.6%), S. sobrinus (50.0%), and A. actinomycetemcomitans (8.3%). Conclusions: AgNPs exhibited considerable antimicrobial potential to be used as a complementary and alternative tool in maintaining and preserving oral health in patients with MIDs.

Root hairs are epidermal cell extensions that increase the root surface for water and nutrient acquisition. Thus, both the initiation and elongation of root hairs are critical for soil exploration and plant adaptation to ever changing growth conditions. Here, we describe the critical roles of two subunits of the Mediator complex, MED12 and MED13, in root hair growth in response to sucrose and abscisic acid, which are tightly linked to abiotic stress resistance. When compared to the WT, med12 and med13 mutants showed increased sensitivity to sucrose and ABA treatments on root meristem and elongation zones that were accompanied with alterations in root hair length and morphology, leading to the isodiametric growth of these structures. The swollen root hair phenotype appeared to be specific, since med8 or med16 mutants did not develop rounded hairs when supplied with 4.8% sucrose. Under standard growth medium, MED12 and MED13 were mainly expressed in root vascular tissues and cotyledons, and their expression was repressed by sucrose or ABA. Interestingly, med12 and med13 mutants manifested exacerbated levels of nitric oxide under normal growth conditions, and upon sucrose supplementation in trichoblast cells, which coincided with root hair deformation. Our results indicate that MED12 and MED13 play non-redundant functions for maintenance of root hair integrity in response to sucrose and ABA and involve nitric oxide as a cellular messenger in Arabidopsis thaliana.

Cellulose hydrogels derived from agave bagasse were formulated to promote the regeneration of gingival connective tissue in lagomorphs. Three treatment modalities were randomly implanted in the gingival diastema area in 16 rabbits. The general characteristics were analyzed and histopathological studies were carried out at 4, 8, 12, and 16 weeks. A chi-squared test was performed using IBM-SPSS version 25, indicating that cellulose hydrogels implanted in lagomorph's gingival tissue showed the presence of greater angiogenesis and fibrogenesis at the four evaluation intervals during 16 consecutive weeks. The presence of inflammatory infiltrates had no significant impact. No significant changes were observed in body weight and water and food intake. This suggests that hydrogels contribute to the regeneration and/or repair of oral connective tissue, showing angiogenesis and fibrogenesis in 50 to 100% of rabbits tested with hydrogel cellulose membrane. Regarding angiogenesis, in the specimens where membranes were implanted, its presence predominated in all variants (50%), followed by diffuse angiogenesis (37.5%), and finally the absence of angiogenesis (12.5%). [ABSTRACT FROM AUTHOR]

Abstract Antimicrobial resistance is a global public health problem. Root canal microbiota associated with apical periodontitis represents a well-known reservoir of antimicrobial resistance genes (ARGs). However, the effect of type 2 diabetes mellitus (T2DM) in this reservoir is unknown. This study aimed to establish if root canal microbiota associated with apical periodontitis in T2DM patients is an augmented reservoir by identifying the prevalence of nine common ARGs and comparing it with the prevalence in nondiabetic patients. Methodology This cross-sectional study included two groups: A T2DM group conformed of 20 patients with at least ten years of living with T2DM and a control group of 30 nondiabetic participants. Premolar or molar teeth with pulp necrosis and apical periodontitis were included. A sample was collected from each root canal before endodontic treatment. DNA was extracted, and ARGs were identified by polymerase chain reaction. Results tetW and tetM genes were the most frequent (93.3 and 91.6%, respectively), while ermA was the least frequent (8.3%) in the total population. The distribution of the ARGs was similar in both groups, but a significant difference (p

It has been proposed that oral commensal bacteria are potential reservoirs of a wide variety of antimicrobial resistance genes (ARGs) and could be the source of pathogenic bacteria; however, there is scarce information regarding this. In this study, three common streptococci of the mitis group (S. oralis, S. sanguinis, and S. gordonii) isolated from dental plaque (DP) were screened to identify if they were frequent reservoirs of specific ARGs (blaTEM, cfxA, tetM, tetW, tetQ, ermA, ermB, and ermC). DP samples were collected from 80 adults; one part of the sample was cultured, and from the other part DNA was obtained for first screening of the three streptococci species and the ARGs of interest. Selected samples were plated and colonies were selected for molecular identification. Thirty identified species were screened for the presence of the ARGs. From those selected, all of the S. sanguinis and S. oralis carried at least three, while only 30% of S. gordonii strains carried three or more. The most prevalent were tetM in 73%, and blaTEM and tetW both in 66.6%. On the other hand, ermA and cfxA were not present. Oral streptococci from the mitis group could be considered frequent reservoirs of specifically tetM, blaTEM, and tetW. In contrast, these three species appear not to be reservoirs of ermA and cfxA.

This study analyzed the role of blood serum in enhancing the mitochondrial metabolism and virulence of Mucorales through rhizoferrin secretion. We observed that the spores of clinically relevant Mucorales produced in the presence of serum exhibited higher virulence in a heterologous infection model of Galleria mellonella. Cell-free supernatants of the culture broth obtained from spores produced in serum showed increased toxicity against Caenorhabditis elegans, which was linked with the enhanced secretion of rhizoferrin. Spores from Mucoralean species produced or germinated in serum showed increased respiration rates and reactive oxygen species levels. The addition of non-lethal concentrations of potassium cyanide and N-acetylcysteine during the aerobic or anaerobic growth of Mucorales decreased the toxicity of the cell-free supernatants of the culture broth, suggesting that mitochondrial metabolism is important for serum-induced virulence. In support of this hypothesis, a mutant strain of Mucor lusitanicus that lacks fermentation and solely relies on oxidative metabolism exhibited virulence levels comparable to those of the wild-type strain under serum-induced conditions. Contrary to the lower virulence observed, even in the serum, the ADP-ribosylation factor-like 2 deletion strain exhibited decreased mitochondrial activity. Moreover, spores produced in the serum of M. lusitanicus and Rhizopus arrhizus that grew in the presence of a mitophagy inducer showed low virulence. These results suggest that serum-induced mitochondrial activity increases rhizoferrin levels, making Mucorales more virulent.

Glass fiber posts (GFP) have an elastic modulus that shares structural characteristics with dentin. Ineffective removal of the smear layer (SL) in the root canal after post space preparation reduces resin tag formation, compromising an efficient hybrid layer formation leading to a subsequent debonding. In this sense, this review article focuses on the published literature related to dentin conditioning for GFP placement with the use of acidic solutions such as EDTA, citric and maleic acid or prefabricated conditioning solutions such as MTAD and QMix, both with/without activation by sonic or laser devices, analyzed by scanning electron microscopy (SEM) and/or push- out bond strength (POBS) test. The collected information suggested that the conditioning agent that showed better results for dentin conditioning increasing the bond strength of the GFP to the root canal is 17% EDTA without activation.

Background and Objectives: Periodontal disease (PD) is a multifactorial oral disease regularly caused by bacterial biofilms. Silver nanoparticles (AgNP) have offered good antimicrobial activity; moreover, there is no available scientific information related to their antimicrobial effects in biofilms from patients with PD. This study reports the bactericidal activity of AgNP against oral biofilms related to PD. Materials and Methods: AgNP of two average particle sizes were prepared and characterized. Sixty biofilms were collected from patients with (30 subjects) and without PD (30 subjects). Minimal inhibitory concentrations of AgNP were calculated and the distribution of bacterial species was defined by polymerase chain reaction. Results: Well-dispersed sizes of AgNP were obtained (5.4 ± 1.3 and 17.5 ± 3.4 nm) with an adequate electrical stability (−38.2 ± 5.8 and −32.6 ± 5.4 mV, respectively). AgNP showed antimicrobial activities for all oral samples; however, the smaller AgNP had significantly the most increased bactericidal effects (71.7 ± 39.1 µg/mL). The most resistant bacteria were found in biofilms from PD subjects (p < 0.05). P. gingivalis, T. denticola, and T. forsythia were present in all PD biofilms (100%). Conclusions: The AgNP showed efficient bactericidal properties as an alternative therapy for the control or progression of PD.

Hydraulic calcium silicate cements (HCSCs) are valuable for various dental procedures. However, several reports document inherent limitations and complaints about their high costs, hindering accessibility in low—and middle-income countries. This study aimed to characterize four low-cost HCSC prototypes to show their microstructure, composition, and fundamental physical properties. Four HCSC prototypes were formulated: 1- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate, 2- calcium silicate powder with 17.5 wt. % replacement of zirconium oxide, 3- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate and 2.5 wt. % of zirconium oxide and 4- calcium silicate powder with 10 wt. % replacement of calcium tungstate and 10 wt. % replacement of zirconium oxide. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to assess their microstructure and composition. Additionally, radiopacity, setting time, solubility, pH, and in vitro bioactivity were evaluated at different time points and contrasted with controls (Mineral trioxide aggregate –MTA Angelus- and Intermediate restorative material -IRM-). Their production cost was significantly lower than commercially available HCSCs. All prototypes exhibited a microstructure and composition comparable to MTA Angelus. All the prototypes exhibited radiopacity exceeding 3 mm of aluminum and shorter initial and final setting times than MTA Angelus. The solubility of some prototypes closely adhered to the ISO standard recommendation of 3% after 1 day, and all promoted an alkaline pH and the formation of calcium/phosphate precipitates. These promising findings suggest the potential clinical application of these prototypes. However, further research is necessary to evaluate their mechanical and biological properties for definitive clinical use. [ABSTRACT FROM AUTHOR]

A biomarker is defined as a characteristic that is measured as an indicator of a normal biological or pathological process, a response to an exposure or intervention. Biomarkers with a diagnostic approach must identify not only the presence but also the absence of the disease with high precision, so having the biological source of the said marker is of vital importance to ensure precision and accuracy; the aim was to carry out a review of its diagnostic potential. The search strategy was carried out in three databases: PubMed, ScienceDirect, and Scopus. The keywords that were used were as follows: "gingival crevicular fluid", "Biomarker", and "Diagnosis", using the Boolean operator "AND". The filter was used at 10 years. Within the type of molecules most studied, the cytokine family was the most abundant with 25.42% of the studies, followed by metalloproteinases and proteins with 16.9% each one. Studies that included RNA‐type genetic material were less frequently found. As has been demonstrated, the use of GCF as a source of biomolecules for diagnostic use has been increasing, both for oral diseases, which reflects the local conditions of the disease; it also has the ability to reflect the development of distant diseases; and this is because GCF is a blood ultrafiltrate. [ABSTRACT FROM AUTHOR]

Lithium niobate perovskite and silver nanoparticle-based nanocomposites (LNB:AgNPs) were explored for developing an electrochemical glucose sensor. The perovskite to silver nanoparticle ratios investigated were 4:1, 1:1, 1:2, 2:1, and 1:4. Among these, the 4:1 ratio, with the lowest silver content, demonstrated the most stable performance during glucose quantification via amperometry. The sensor's response was evaluated measuring the current at a fixed potential of 0.7 V following the injection of 1 mM glucose with each addition. The calibration curve obtained from the recorded data exhibited a linear response within the 1 to 15 mM glucose concentration range, achieving a sensitivity of 2 μA/mM, a high correlation coefficient (R2 = 0.997), and a limit of detection (LOD) of 0.5 µM. The LNB4:1AgNP composite allowed taking advantage of the unique properties of both components in a balanced manner, maximizing the sensor performance in practical applications. [ABSTRACT FROM AUTHOR]

Hydrogels elaborated from Dasylirion spp. and enriched with grape seed extract (GSE) were investigated for tentative use in dental treatment. Cellulose-GSE hydrogels were elaborated with varying GSE contents from 10 to 50 wt%. The mechanical and physical properties, antimicrobial effect, biocompatibility, and in vitro cytotoxicity were studied. In all the cases, the presence of GSE affects the hydrogel's mechanical properties. The elongation decreased from 12.67 mm for the hydrogel without GSE to 6.33 mm for the hydrogel with the highest GSE content. The tensile strength decrease was from 52.33 N/mm2 (for the samples without GSE) and went to 40 N/mm2 for the highest GSE content. Despite the adverse effects, hydrogels possess suitable properties for manipulation. In addition, all hydrogels exhibited excellent biocompatibility and no cytotoxicity, and the antibacterial performance was demonstrated against S. mutans, E. Faecalis, S. aureus, and P. aureginosa. Furthermore, the hydrogels with 30 wt% GSE inhibited more than 90% of the bacterial growth. [ABSTRACT FROM AUTHOR]

The Tropical Indo-Pacific (TIP) includes about two thirds of the world's tropical oceans and harbors an enormous number of marine species. The distributions of those species within the region is affected by habitat discontinuities and oceanographic features. As well as many smaller ones, the TIP contains seven large recognized biogeographic barriers that separate the Red Sea and Indian Ocean, the Indian from the Pacific Ocean, the central and eastern Pacific, the Hawaiian archipelago, the Marquesas and Easter Islands. We examined the genetic structuring of populations of Cirrhitichthys oxycephalus, a small cryptic species of reef fish, across its geographic range, which spans the longitudinal limits of the TIP. We assessed geographic variation in the mitochondrial cytb gene and the nuclear RAG1 gene, using 166 samples collected in 46 localities from the western to eastern edges of the TIP. Sequences from cytb show three well-structured groups that are separated by large genetic distances (1.58–2.96%): two in the Tropical Eastern Pacific (TEP), one at Clipperton Atoll another occupying the rest of that region and the third that ranges across the remainder of the TIP, from the central Pacific to the Red Sea and South Africa. These results indicate that the ~4,000 km wide Eastern Pacific Barrier between the central and eastern Pacific is an efficient barrier separating the two main groups. Further, the ~950 km of open ocean that isolates Clipperton Atoll from the rest of the TEP is also an effective barrier. Contrary to many other cases, various major and minor barriers from the Central Indo-Pacific to the Red Sea are not effective against dispersal by C. oxycephalus, although this species has not colonized the Hawiian islands and Easter Island. The nuclear gene partially supports the genetic structure evident in cytb, although all haplotypes are geographically mixed. [ABSTRACT FROM AUTHOR]

Purpose: Patients undergoing radiotherapy for head or neck cancer often require root canal treatments, which can be compromised by the effects of radiation. This investigation aimed to determine whether ionizing radiation (IR), in doses similar to those used in conventional therapy, affects the surface and physicomechanical properties of various brands of endodontic gutta-percha points (EGPs). Materials and Methods: One hundred and twenty-three EGPs from three brands (Meta-Biomed, Dentsply, and Hygenic) were divided into groups and either exposed or not exposed to IR at a total dose of 50 Gy, divided into 25 fractions. Tensile strength and microhardness tests were performed on all EGPs. Scanning electron microscopy was utilized to identify possible microstructural surface changes due to IR exposure. The proportion of organic to inorganic components in each brand was also determined. Results: Exposure to IR resulted in significant changes only in the EGPs from the Meta-Biomed brand, including a notable decrease in tensile strength and an increase in microhardness. Furthermore, the surface microstructure of these EGPs displayed dark lines and striations over a large area, with some lines deeply embedded in the center and cavities of variable depths and extensions observed, leading to irregular and non-smooth surfaces. This brand had the highest proportion of organic components. Conclusion: The physicomechanical properties and surface microstructure of Meta-Biomed brand EGPs were significantly affected by IR at doses used in conventional therapy for head or neck cancer, while the other brands were less affected or unaffected. [ABSTRACT FROM AUTHOR]

Objective: Dental caries is the most prevalent disease globally, and Streptococcus mutans ( S. mutans ) is a common associated oral bacteria. Additionally, S. mutans possess esterase activity capable of degrading resin composites (RC). However, the effect of degradation on the physical-mechanical properties of the RC has not been extensively studied. We evaluated the flexure strength (FS), the diametral tensile strength (DTS), the modulus of elasticity (ME), and the microhardness of three contemporary RC to establish if S. mutans could affect them. Methods: One hundred thirty-eight bar-shaped and 276 disc-shaped specimens were fabricated with Enamel Plus HRi, IPS Empress Direct, and Clearfil AP-X, and physical-mechanical testing was done after been incubated during 30 and 60 days in culture media with or without S. mutans . Also, a scanning electron microscope was used to identify surface changes. Results: None of the tested RC were affected in their mechanical properties (FS, ME, and DTS). However, Clearfil AP-X and Enamel Plus HRI showed eroded surfaces and a decreased microhardness after 30 and 60 days S. mutans incubation. IPS Empress Direct presented the lowest values in all the tests, but its physical-mechanical features and surface were not affected by bacteria’s exposure. Conclusions: Exposure to S. mutans could affect some contemporary RC; however, the effect seems superficial since its mechanical features were not affected.