Dynamic tensile viscoelastic properties of porcine periodontal ligament.

The periodontal ligament plays a significant role in orthodontic and masticatory processes. To explicitly investigate the effects of dynamic force amplitude and frequency on the dynamic tensile properties of the periodontal ligament, in vitro tensile experiments were conducted using a dynamic mechanical analysis at various dynamic force amplitudes across a wide frequency range. Storage modulus, loss modulus, and loss factor values were measured. A Maxwell constitutive model based on modulus was established to describe the dynamic mechanical properties of the periodontal ligament. The results showed that the storage modulus ranged from 29.53 MPa to 158.24 MPa, the loss modulus ranged from 3.26 MPa to 76.16 MPa, and the loss factor values all increased with higher frequencies and higher dynamic force amplitudes. Based on the parameters obtained from the fitting results, it is evident that the short-term response has a more pronounced impact on the elastic response of the periodontal ligament than the long-term response. Increasing the dynamic force amplitude and its frequency amplified the viscous effects of the periodontal ligament and enhanced energy dissipation. The proposed constitutive model further demonstrated that the periodontal ligament acts as a viscoelastic biomaterial. These findings have implications for future research on the periodontal ligament.

In vitro antifungal and physicochemical properties of polymerized acrylic resin containing strontium-modified phosphate-based glass.

Acrylic resins are widely used as the main components in removable orthodontic appliances. However, poor oral hygiene and maintenance of orthodontic appliances provide a suitable environment for the growth of pathogenic microorganisms. In this study, strontium-modified phosphate-based glass (Sr-PBG) was added to orthodontic acrylic resin at 0% (control), 3.75%, 7.5%, and 15% by weight to evaluate the surface and physicochemical properties of the novel material and its in vitro antifungal effect against Candida albicans (C. albicans). Surface microhardness and contact angle did not vary between the control and 3.75% Sr-PBG groups (p > 0.05), and the flexural strength was lower in the experimental groups than in the control group (p < 0.05), but no difference was found with Sr-PBG content (p > 0.05). All experimental groups showed an antifungal effect at 24 and 48 h compared to that in the control group (p < 0.05). This study demonstrated that 3.75% Sr-PBG exhibits antifungal effects against C. albicans along with suitable physicochemical properties, which may help to minimize the risk of adverse effects associated with harmful microbial living on removable orthodontic appliances and promote the use of various materials.

CYLD inhibits osteoclastogenesis to ameliorate alveolar bone loss in mice with periodontitis.

Periodontitis is a chronic immune inflammatory disease that can lead to the destruction and loss of the tooth-supporting apparatus. During this process, the balance between bone absorption mediated by osteoclasts and bone formation mediated by osteoblasts is damaged. Consistent with previous studies, we observed that depletion of cylindromatosis (CYLD) resulted in an osteoporotic bone phenotype. However, the effect of CYLD deficiency on periodontitis is undetermined. Here, we investigated whether CYLD affects periodontal tissue homeostasis in experimental periodontitis in Cyld knockout (KO) mice, and we explored the underlying mechanisms. Interestingly, we discovered significant alveolar bone density loss and severely reduced alveolar bone height in Cyld KO mice with experimentally induced periodontitis. We observed increased osteoclast number and activity in both the femurs and alveolar bones, accompanied by the downregulation of osteogenesis genes and upregulation of osteoclastogenesis genes of alveolar bones in ligatured Cyld KO mice. Taken together, our findings demonstrate that the deletion of CYLD in mice plays a vital role in the pathogenesis of periodontal bone loss and suggest that CYLD might exert an ameliorative effect on periodontal inflammatory responses.

Effect of multiple firings on the marginal fit of monolithic zirconia crowns: An in vitro study.

STATEMENT OF PROBLEM: Speed sintering was introduced to save chair time and produce monolithic zirconia restorations in a single visit. Multiple firings are usually required clinically for both speed-sintered and conventionally sintered monolithic zirconia crowns. However, the effects of multiple firings on the marginal fit of speed-sintered and conventionally sintered monolithic zirconia crowns are unknown. PURPOSE: The purpose of this in vitro study was to investigate the effect of multiple firings on the marginal fit of speed-sintered and conventionally sintered monolithic zirconia crowns. MATERIAL AND METHODS: Twenty conventionally sintered and 20 speed-sintered monolithic zirconia crowns were milled, sintered, and repeatedly fired by using conventional sintering and speed sintering furnaces. The absolute marginal discrepancy of the crowns was measured with a measuring microscope at ×100 magnification after sintering (T0) and after the first (T1), second (T2), and third firings (T3). Two-way repeated-measures ANOVA was used to detect the impact of multiple firings on the absolute marginal discrepancy of conventionally sintered and speed-sintered monolithic zirconia crowns and the differences between the 2 materials (α=.05). RESULTS: Multiple firings improved the absolute marginal discrepancy of conventionally sintered and speed-sintered monolithic zirconia crowns (P<.001). The absolute marginal discrepancy of conventionally sintered monolithic zirconia crowns at T2 and T3 was significantly smaller than that at T1 (P=.008 and 0.016, respectively), and the absolute marginal discrepancy of speed-sintered monolithic zirconia crowns at T2 was significantly smaller than that at T1 (P=.015). The speed-sintered monolithic zirconia crowns had a better marginal fit than conventionally sintered monolithic zirconia crowns (P=.008). No significant interaction was found between the multiple firings and material types on the absolute marginal discrepancy of monolithic zirconia crowns (P=.914). CONCLUSIONS: Multiple firing cycles can significantly improve the marginal fit of conventionally sintered and speed-sintered monolithic zirconia crowns. The speed-sintered monolithic zirconia crowns have a better marginal fit (both vertically and horizontally) than the conventionally sintered monolithic zirconia crowns.

Effects of incorporating 45S5 bioactive glass into 30% hydrogen peroxide solution on whitening efficacy and enamel surface properties.

OBJECTIVES: This study aimed to evaluate the effects of 30% hydrogen peroxide (HP) solution containing various contents of 45S5 bioactive glass (BAG) on whitening efficacy and enamel surface properties after simulating the clinical bleaching procedure. MATERIALS AND METHODS: A total of 60 bovine enamel specimens discolored with black tea were divided into five groups treated with distilled water (DW), HP, 0.01 wt.% BAG + HP, 1.0 wt.% BAG + HP, and 20.0 wt.% BAG + HP (n = 12). The pH change was observed for 20 min immediately after mixing the experimental solutions, which were applied for 20 min/week, at 37 °C over 21 days. Color, gloss, roughness, microhardness, and micromorphology measurements were conducted before and after bleaching treatment. RESULTS: All groups containing BAG experienced an increase in pH from 3.5 to 5.5 in less than 1 min, and the final pH increased as the BAG content increased. The ΔE of all experimental groups was significantly higher than that of the DW group (p < 0.05), but there were no significant differences between different BAG contents (p > 0.05). Gloss significantly decreased in all experimental groups compared to the DW group, and the increased BAG content had significantly affected the decrease in gloss (p < 0.05). There was no statistical difference in surface roughness (p > 0.05), but hardness increased significantly with BAG content after bleaching treatment (p < 0.05). CONCLUSIONS: HP containing 45S5 BAG showed efficacy in tooth whitening. Also, the pH value of the HP remained acidic near 3.5 for 20 min, while the HP containing the 45S5 BAG showed an increase in pH, which inhibited the demineralization of the enamel surface, and maintained the surface morphology. CLINICAL RELEVANCE: These novel materials are promising candidates to minimize enamel surface damage caused by HP during bleaching procedure in dental clinic.

Effects of 35% hydrogen peroxide solution containing hydrated calcium silicate on enamel surface.

OBJECTIVES: The objectives of this study were to develop a novel bleaching material containing hydrated calcium silicate (hCS) particles and investigate the effects of hCS on the bleaching efficacy, microhardness, and surface morphology of bovine enamel. MATERIALS AND METHODS: To prepare the hCS particles, white Portland cement was mixed with distilled water and ground into a fine powder. The particles in various proportions were then mixed with 35% hydrogen peroxide solution (HP), while HP without hCS was used as a control (HP), and teeth whitening gel was used as a commercial control (CC). Following the thrice application of experimental and control solutions on the discolored bovine enamel surface for 15 min, color change (n = 10), microhardness (n = 10), and micromorphology (n = 2) of the enamel surface were analyzed. RESULTS: The Δ E* of the enamel surface treated with the experimental solution containing hCS was significantly higher than that of the CC, but there were no significant differences between the different hCS contents. The experimental solution containing hCS reduced the percentage of microhardness loss on the enamel surface, and the percentage of microhardness loss significantly decreased as the content of hCS increased (p < 0.05). The erosion pattern was only observed on enamel surfaces treated with HP and CC. CONCLUSIONS: This study suggests that HP containing hCS is effective in bleaching efficacy. In addition, hCS could also minimize the microhardness loss of tooth structure caused by HP and maintain enamel surface morphology. CLINICAL RELEVANCE: This novel bleaching material is promising for inhibiting demineralization and promoting the remineralization of teeth during bleaching treatment in dental clinics.

The colossal role of H-MnO2-PEG in ischemic stroke.

Stroke is one of the most serious problems that seriously affect people's health and brings huge economic burden to society. The development of new nanocarriers with desired degradability and targeted ability is of great significance for efficient drug delivery. In recent years, nano drug delivery system has developed rapidly and applied to treat ischemic stroke. Here, we report the synthesis and functionalization of monodisperse hollow structured MnO2 (H-MnO2). The highly monodisperse H-MnO2 with uniform morphology was obtained by in situ growing MnO2 on solid silica nanoparticles and subsequently removing the silica core. After successive modification of poly ethylene glycol(PEG), we further verified their protective effect on ischemic stroke in our study.

Time-dependent effects after enamel fluoride application on an acid etching system in orthodontic bracket bonding.

OBJECTIVES: This study investigated the effectiveness of acid etching and bond strength in an orthodontic bonding system in accordance with various time periods after 1.23% acidulated phosphate fluoride (APF) gel applications. MATERIALS AND METHODS: APF gel was applied on the enamel surface of bovine teeth, which were assigned to group F0. The tooth specimens were then immersed in distilled water for 1 (F1), 7 (F7), 14 (F14), 21 (F21) and 28 (F28) days. A group without fluoride pretreatment was a control group. All groups were etched with 35% phosphoric acid and evaluated using a surface hardness tester and scanning electron microscope (SEM). A shear bond strength (SBS) test was performed using a universal testing machine, and the bond failure modes were also examined. RESULTS: After the 1.23% APF gel treatment, the hardness of the acid-etched enamel surface decreased as the immersion period increased. SEM images of the test groups showed etched patterns similar to control group as the immersion period increased. The SBS increased with increasing immersion period, whereas group F21 was not significantly different from the control group. Relatively high adhesive remnant index scores were identified as the ageing period increased. CONCLUSIONS: The present study indicated that in order to obtain suitable bond strength, it is recommended to use an acid etching-based bonding system for the fixation of orthodontic appliances on the enamel surface 21 days after the use of APF gel. CLINICAL RELEVANCE: Fluoride pre-treatment interferes with the acid etching effects on enamel, causing a reduction in the bond strength with orthodontic brackets.

Stress and its association with academic performance among dental undergraduate students in Fujian, China: a cross-sectional online questionnaire survey.

BACKGROUND: The aim of this study was to investigate the amount and sources of stress in dental undergraduate students in Fujian, China, and the factors associated with stress. METHODS: This cross-sectional study was conducted during the second semester of the 2017-2018 academic year at the School of Stomatology, Fujian Medical University, China. A total of 396 students were surveyed with the Dental Environment Stress Questionnaire (DES) and the Perceived Stress Scale (PSS) using an online survey system. The participants' demographic information, including sex, age, year of study, and grade point average (GPA) was also collected. One-way analysis of variance (ANOVA) was performed to compare the stress scores. Pearson correlation and multiple linear regression analyses were conducted to explore the associated factors of stress and academic performance. All statistical analyses were performed at a significance level of 5%. RESULTS: A total of 347 undergraduate students participated in the present study, for a response rate of 87.6%. There were no significant differences in the DES and PSS total scores among students of different grades and sexes. Significant differences were found in the DES "workload" and "self-efficacy beliefs" scores among students from different study years (all P < 0.05). The Multiple linear regression showed that DES and PSS scores were negatively correlated with GPA, while sex was positively correlated with GPA (all P < 0.05). Female students had significantly higher GPAs than male students. CONCLUSIONS: Dental undergraduates in Fujian, China experienced moderate levels of stress. While the amount of stress did not differ by year of study, the sources of stress did differ. Stress scores and sex were negatively correlated with academic performance.

Two Cases of Chloromethylisothiazolinone and Methylisothiazolinone-associated Toxic Lung Injury.

Previous animal studies have not conclusively determined the association between exposure to humidifier disinfectants (HDs) containing 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and/or 2-methyl-4-isothiazolin-3-one (MIT) and development of HD-associated lung injuries. Nonetheless, patients exposed to HDs containing only CMIT and/or MIT showed clinically similar lung injuries to those exposed to HDs containing polyhexamethylene guanidine (PHMG) or oligo (2-[2-ethoxy]ethoxyethyl) guanidinium chloride (PGH). Here, we report twin sisters with lung injuries associated with exposure to CMIT/MIT-containing HDs. At 6 months of age, a younger twin sister presented with the 3-day history of cough, sputum, and respiratory difficulty. Chest radiography revealed multiple patchy consolidation and ground-glass opacities with pneumothorax and pneumomediastinum. Thoracostomy was performed due to pneumothorax at admission and she was discharged at 11 days of hospitalization. At 5 years of age, multiple tiny nodules and faint centrilobular ground-glass opacities were observed with the small pneumatocele. The elder sister visited a tertiary hospital due to dyspnea at 12 months of age. Chest radiography showed consolidation, pneumomediastinum, and pulmonary interstitial emphysema. There was no response to the administration of immunosuppressant drugs and antifibrotic agents. At 5 years of age, chest CT revealed ground-glass opacity and multiple tiny centrilobular ground-glass opacities nodules in both lungs with exercise intolerance.

HBsAg and HBeAg in the prediction of a clinical response to peginterferon α-2b therapy in Chinese HBeAg-positive patients.

BACKGROUND: This study aimed to evaluate the predictive values of hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) levels in 171 Chinese patients with chronic hepatitis B who received a 48-week course of pegylated interferon alfa-2b therapy at 1.5 mcg/kg. METHODS: HBsAg, HBeAg, and hepatitis B virus (HBV) DNA levels were measured at baseline and weeks 12, 24, 48, and 72. Clinical responses were defined as a combined response (CR, HBeAg seroconversion [sustained response, SR] combined with HBV DNA level <2,000 IU/mL at week 72). The positive predictive value and negative predictive value were calculated for HBsAg alone and/or combined with HBeAg and HBV DNA at weeks 12 and 24. RESULTS: Of 171 patients included, 58 (33.9 %) achieved a SR. Of patients who achieved a SR, 33 (56.9 %) achieved a CR. Totally 19.3 % (33/171) patients achieved CR and 80.7 % (138/171) patients did not. Patients with HBsAg <1500 IU/mL at week 12 had a 47.4 % chance of achieving an off-treatment SR and patients with a HBsAg decrease >1.5 logIU/mL at week 12 had a 54.5 % chance. Patients with HBsAg >20,000 IU/mL at weeks 12 and 24 had a 93.8 and 100.0 % chance, respectively, of not achieving a CR. An HBsAg level or changes at weeks 12 and 24, combined with HBeAg or HBV DNA, increased the chance for a SR and CR. CONCLUSIONS: On-treatment HBsAg quantification, alone or in combination with HBeAg or HBV DNA, predicted off-treatment SR and CR after 48 weeks of PEG-IFNα-2b therapy, and thus, may guide clinicians in making a therapeutic decision to continue or terminate the therapy.

Hydrated Calcium Silicate in Resin Composites for Prevention of Secondary Caries.

INTRODUCTION AND AIMS: The gaps at the margins of restorative composite resin can increase as the carious process occurs underneath the materials, causing further demineralization along the tooth cavity wall. The aim of this study was to evaluate the effects of restorative resin composite containing hydrated calcium silicate (hCS) filler on enamel protection against demineralization by simulating microleakage between the test material and teeth in a cariogenic environment. METHODS: The experimental resin composites were composed of 70 wt.% filler, which was mixed with a glass filler and hCS in a weight ratio of 70.0% glass (hCS 0), 17.5% hCS + 52.5% glass (hCS 17.5), 35.0% hCS + 35.0% glass (hCS 35.0), and 52.5% hCS + 17.5% glass (hCS 52.5). A light-cured experimental resin composite disk was positioned over a polished bovine enamel disk, separated by a 30-µm gap, and immersed in artificial saliva with pH 4.0 for 15, 30, and 60 days. After the immersion period, the enamel disk was separated from the resin composite disk and evaluated using a microhardness tester, atomic force microscopy, and polarized light microscopy. The opposing sides of the enamel and resin composite disks were observed using scanning electron microscopy/energy dispersive X-ray spectrometry. RESULTS: The enamel surface showed a significant increase in microhardness, decreased roughness, and remineralization layer as the proportion of hCS increased (P < .05). In the scanning electron microscopy image, the enamel surface with hCS 35.0 and 52.5 after all experimental immersion periods, showed a pattern similar to that of a sound tooth. CONCLUSIONS: The results demonstrated that increasing the hCS filler level of restorative resin composites significantly decreased enamel demineralization. CLINICAL RELEVANCE: Hydrated calcium silicate laced restorative resin composites may be a promising dental biomaterial for protecting teeth against demineralization and preventing secondary caries around restorations.

Color stability, surface, and physicochemical properties of three-dimensional printed denture base resin reinforced with different nanofillers.

Various materials have been introduced for the three-dimensional (3D) printing of dentures. In this study, the color stability and surface and physicochemical properties of 3D-printed denture base resins with four types of nanofiller particles were evaluated. Al2O3, ZnO, CeZr, and SiO2 nanofillers were added to a 3D printable denture base-resin matrix and subjected to digital light processing. The specimens were immersed in Coke, coffee, black tea, or distilled water for 6 days. For the assessment of color differences, 6 samples were analyzed using a spectrophotometer. In a separate investigation, surface properties of 10 samples were examined, while a different set of 6 samples was used to analyze water sorption and solubility. All experimental groups exhibited higher color stability in Coke than the control group. However, the groups containing ZnO and CeZr had lower color stability in coffee and black tea than the control group. Moreover, they had agglomerated nanofillers and lower gloss than the control group. Compared with that of the control group, the contact angle of the CeZr group and microhardness of the ZnO group were not significantly different. Water sorption was higher in the Al2O3 group, whereas the solubility of the experimental and control groups was not statistically significant. The results demonstrated the significant effect of ZnO and CeZr nanofillers on the color stability of the dentures when exposed to discoloring beverages. These results will facilitate the development of fillers that enhance the resistance of 3D printed denture base resins to discoloration in the oral environment.

Er:YAG laser settings for debonding zirconia restorations: An in vitro study.

This in vitro study aimed to determine the optimal frequency and energy settings for debonding zirconia restorations using an erbium-doped yttrium aluminum garnet (Er:YAG) laser. A total of 200 zirconia specimens (5 mm × 5 mm × 1.5 mm) were fabricated from two types of materials: (1) 3 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (3Y-TZP) and (2) 5 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (5Y-TZP). The zirconia specimens were bonded to dentin using resin cement (RelyX Ultimate, 3 M) and divided into 20 groups based on their laser treatments (n = 5). Er:YAG laser treatment was applied at various frequencies (10 Hz and 20 Hz) and energies (80 mJ, 100 mJ, 120 mJ, 140 mJ, 160 mJ, 180 mJ, 200 mJ, 220 mJ, 240 mJ, and 260 mJ). The time required to debond the specimens and the temperature changes that dentin underwent during the laser treatment were recorded. The surface morphologies of the debonded dentin and zirconia specimens were observed using scanning electron microscopy (SEM). Additional zirconia specimens were fabricated for 4-point flexural strength testing and surface roughness measurements. Statistical analyses were conducted using three-way analysis of variance (ANOVA) and Student-Newman-Keuls (SNK)-q tests (α = 0.05). The debonding time of each specimen varied between 4.8 and 160.4 s, with an average value of 59.2 s. The dentin temperature change for each specimen ranged from 2.3 to 3.6 °C, with an average value of 2.7 °C. The debonding time was significantly influenced by the zirconia material type and laser energy, but it was not affected by the laser frequency. Among the specimens, those made of 3Y-TZP needed significantly more time for debonding than 5Y-TZP. The optimal energies were 220 mJ for 3Y-TZP and 200 mJ for 5Y-TZP. The laser frequency, laser energy, and type of zirconia material had no effect on the dentin temperature change. Additionally, no surface alternations were observed on the dentin or zirconia materials after laser treatment. The surface roughness and flexural strength of the zirconia materials remained unchanged after laser treatment. In summary, Er:YAG laser treatment effectively and safely removes zirconia restorations without impacting their mechanical properties, with a safe temperature change of less than 5.6 °C. The optimum frequency and energy settings for debonding 3Y-TZP and 5Y-TZP restorations were found to be 10/20 Hz and 220 mJ and 10/20 Hz and 200 mJ, respectively.

Molecular imprinted polymers for separation science: a review of reviews.

Molecular imprinted polymer is an artificial receptor made by imprinting molecules of a template in a polymer matrix followed by removing the template molecules via thorough washing to give the permanent template grooves. They show favored affinity to the template molecule compared to other molecules, and this property is the basic driving force for such diverse application of this techniques. Such techniques have been increasingly employed in a wide scope of applications such as chromatography, sample pretreatment, purification, catalysts, sensors, and drug delivery, etc., mostly in bioanalytical areas. A major part of them is related to development of new stationary phases and their application in chromatography and sample pretreatment. Embodiments of molecular imprinted polymer materials have been carried out in a variety of forms such as irregularly ground particles, regular spherical particles, nanoparticles, monoliths in a stainless steel or capillary column, open tubular layers in capillaries, surface attached thin layers, membranes, and composites, etc. There have been numerous review articles on molecular imprinted polymer issues. In this special review, the reviews in recent ca. 10 years will be categorized into several subgroups according to specified topics in separation science, and each review in each subgroup will be introduced in the order of date with brief summaries and comments on new developments and different scopes of prospects. Brief summaries of each categories and conclusive future perspectives are also given.

Poly (Methyl Methacrylate)-Containing Silver-Phosphate Glass Exhibits Potent Antimicrobial Activity without Deteriorating the Mechanical and Biological Properties of Dental Prostheses.

Poly (methyl methacrylate) (PMMA) is a commonly used denture material with poor antimicrobial effects. This study investigated the antimicrobial effects of PMMA-containing silver-phosphate glass. We fabricated a novel material comprising PMMA-containing silver-phosphate glass. Then, microhardness, flexural strength, and gloss unit were analyzed. Antimicrobial activity against Streptococcus mutans and Candida albicans was investigated. Colony-forming units were counted, and antimicrobial rates were measured. Biocompatibility tests were performed using a colorimetric MTT assay for evaluating cell metabolic activity. The microhardness, flexural strength, and gloss unit of the experimental groups (with silver-phosphate glass) were not significantly different from those of the control group (no silver-phosphate glass) (P > 0.05), which showed clinically valid values. With increasing proportions of silver-phosphate glass, the antimicrobial activity against the two microorganisms increased (P < 0.05). Furthermore, S. mutans showed more than 50% antimicrobial activity in 4%, 6%, and 8% experimental groups, C. albicans showed more than 50% antimicrobial activity in 6% and 8% groups, and a statistically significant difference in antimicrobial activity was observed compared to the control (P < 0.05). The cell viability of the experimental groups was not significantly different from that of the control group (P > 0.05). Both control and experimental groups showed approximately 100% cell viability. These results suggest that silver-phosphate glass is a promising antimicrobial material in dentistry.

Effect of Acidic Solutions on the Surface Roughness and Microhardness of Indirect Restorative Materials: A Systematic Review and Meta-analysis

PURPOSE: To evaluate the effects of acidic solutions on the surface roughness (SR) and surface microhardness (SMH) of indirect restorative materials by analyzing in vivo and in vitro studies. MATERIALS AND METHODS: Studies comparing the SR and SMH of indirect restorative materials after erosion were included in the meta-analysis. Meta-analyses were conducted with a random-effects model at a significance level of P < .05 using Review Manager software (Cochrane Collaboration). The literature search was conducted using Web of Science, MEDLINE (PubMed), and the Cochrane Library, with no limitations on publication year. RESULTS: Of the 1,097 potentially relevant studies, 32 full-text articles were assessed for eligibility. A total of 16 articles were included in the systematic review, and 15 were included in the meta-analyses. The kappa score between the two reviewers was 0.80. The effects of erosion on ceramics, indirect composites, and hybrid ceramics were evaluated by immersion in or rinsing with acidic solutions (eg, hydrochloric acid [HCl], cola drinks, and juices). An increase in the SR (Ra values) (P < .00001; mean difference [MD] = -0.04; 95% CI = -0.06 to -0.03) and a decrease in the SMH (Vickers microhardness) (P < .00001; MD = 13.94; 95% CI = 12.33 to 15.55) were found after erosion. Subgroup analyses revealed that in vitro erosion led to significantly higher Ra values and lower VHN values than in vivo erosion; cola drinks and juices led to more surface degradation than HCl; and the SR and SMH of polymer-infiltrated ceramic network (PICN) materials remained unchanged after erosion. CONCLUSION: After acidic challenges, a significantly rougher and softened surface was found for indirect restorative materials. Among all the indirect restorative materials, PICN showed the best acid resistance. Nevertheless, the changes in the SR and SMH of indirect restorative materials after erosion detected in the present study were minor and may not have any clinical significance.

Novel antibacterial and apatite forming restorative composite resin incorporated with hydrated calcium silicate.

BACKGROUND: White Portland cement is a calcium silicate material. It exhibits antibacterial properties and is biocompatible. In addition, calcium silicate-based materials are known to release calcium ions and form apatite. The purpose of this study was to develop a novel bioactive restorative resin composite with antibacterial and apatite forming properties to prevent tooth caries at the interface of teeth and restorative materials, by incorporation of hydrated calcium silicate (hCS) derived from white Portland cement. METHODS: To prepare the experimental composite resins, a 30 wt% light-curable resin matrix and 70 wt% filler, which was mixed with hCS and silanized glass powder were prepared in following concentrations: 0, 17.5, 35.0, and 52.5 wt% hCS filler. The depth of cure, flexural strength, water sorption, solubility, and antibacterial effect were tested. After immersion in artificial saliva solution for 15, 30, 60, and 90 days, ion concentration by ICP-MS and apatite formation using SEM-EDS, Raman spectroscopy and XRD from experimental specimens were analyzed. RESULTS: All experimental groups showed clinically acceptable depths of cure and flexural strength for the use as the restorative composite resin. Water sorption, solubility, released Ca and Si ions increased with the addition of hCS to the experimental composite resin. Experimental groups containing hCS showed greater antibacterial effects compared with the 0 wt% hCS filler group (p < 0.05). The 52.5 wt% hCS filler group produced precipitates mainly composed of Ca and P detected as hydroxyapatite after immersion in artificial saliva solution for 30, 60, and 90 days. CONCLUSIONS: This results show that composite resins containing hCS filler is effective in antibacterial effects. hCS has also apatite formation ability for reducing gap size of microleakage by accumulating hydroxyapatite precipitates at the restoration-tooth interface. Therefore, novel composite resin containing hCS is promising bioactive resin because of its clinically acceptable physiochemical properties, antibacterial properties, and self-sealing potential for prevention of microleakage for longer usage of restorations.

The organism fate of inland freshwater system under micro-/nano-plastic pollution: A review of past decade.

Micro- and nano-plastics (MPs/NPs) are characterized by their small size and extensive surface area, making them global environmental pollutants with adverse effects on organisms at various levels, including organs, cells, and molecules. Freshwater organisms, such as microalgae, emerging plants, zooplankton, benthic species, and fish, experience varying impacts from MPs/NPs, which are prevalent in both terrestrial and aquatic inland environments. MPs/NPs significantly impact plant physiological processes, including photosynthesis, antioxidant response, energy metabolism, and nitrogen removal. Extended exposure and ingestion to MPs/NPs might cause metabolic and behavioral deviations in zooplankton, posing an extinction risk. Upon exposure to MPs/NPs, both benthic organisms and fish display behavioral and metabolic disturbances, due to oxidative stress, neural toxicity, intestinal damage, and metabolic changes. Results from laboratory and field investigations have confirmed that MPs/NPs can be transported across multiple trophic levels. Moreover, MPs/NPs-induced alterations in zooplankton populations can impede energy transfer, leading to food scarcity for filter-feeding fish, larvae of benthic organism and fish, thus jeopardizing aquatic ecosystems. Furthermore, MPs/NPs can harm the nervous systems of aquatic organisms, influencing their feeding patterns, circadian rhythms, and mobility. Such behavioral alterations might also introduce unforeseen ecological risks. This comprehensive review aims to explore the consequences of MPs/NPs on freshwater organisms and their interconnected food webs. The investigation encompasses various aspects, including behavioral changes, alterations in physiology, impacts on metabolism, transgenerational effects, and the disruption of energy transfer within the ecosystem. This review elucidated the physiological and biochemical toxicity of MPs/NPs on freshwater organisms, and the ensuing risks to inland aquatic ecosystems.

Exome sequencing is an efficient tool for genetic screening of Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neuropathies and is a genetically and clinically heterogeneous disorder with variable inheritance modes. As several molecules have been reported to have therapeutic effects on CMT, depending on the underlying genetic causes, exact genetic diagnostics have become very important for executing personalized therapy. Whole-exome sequencing has recently been introduced as an available method to identify rare or novel genetic defects from genetic disorders. Particularly, CMT is a model disease to apply exome sequencing because more than 50 genes (loci) are involved in its development with weak genotype-phenotype correlation. This study performed the exome sequencing in 25 unrelated CMT patients who revealed neither 17p12 duplication/deletion nor several major CMT genes. This study identified eight causative heterozygous mutations (32%). This detection rate seems rather high because each sample was tested before the study for major genetic causes. Therefore, this study suggests that the exome sequencing can be a highly exact, rapid, and economical molecular diagnostic tool for CMT patients who are tested for major genetic causes.