scholarly journals Rehardening and the Protective Effect of Gamma-Polyglutamic Acid/Nano-Hydroxyapatite Paste on Surface-Etched Enamel

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4268
Author(s):  
Nai-Chia Teng ◽  
Aditi Pandey ◽  
Wei-Hsin Hsu ◽  
Ching-Shuan Huang ◽  
Wei-Fang Lee ◽  
...  

Many revolutionary approaches are on the way pertaining to the high occurrence of tooth decay, which is an enduring challenge in the field of preventive dentistry. However, an ideal dental care material has yet to be fully developed. With this aim, this research reports a dramatic enhancement in the rehardening potential of surface-etched enamels through a plausible synergistic effect of the novel combination of γ-polyglutamic acid (γ-PGA) and nano-hydroxyapatite (nano-HAp) paste, within the limitations of the study. The percentage of recovery of the surface microhardness (SMHR%) and the surface parameters for 9 wt% γ-PGA/nano-HAp paste on acid-etched enamel were investigated with a Vickers microhardness tester and an atomic force microscope, respectively. This in vitro study demonstrates that γ-PGA/nano-HAp treatment could increase the SMHR% of etched enamel to 39.59 ± 6.69% in 30 min. To test the hypothesis of the rehardening mechanism and the preventive effect of the γ-PGA/nano-HAp paste, the surface parameters of mean peak spacing (Rsm) and mean arithmetic surface roughness (Ra) were both measured and compared to the specimens subjected to demineralization and/or remineralization. After the treatment of γ-PGA/nano-HAp on the etched surface, the reduction in Rsm from 999 ± 120 nm to 700 ± 80 nm suggests the possible mechanism of void-filling within a short treatment time of 10 min. Furthermore, ΔRa-I, the roughness change due to etching before remineralization, was 23.15 ± 3.23 nm, while ΔRa-II, the roughness change after remineralization, was 11.99 ± 3.90 nm. This statistically significant reduction in roughness change (p < 0.05) implies a protective effect against the demineralization process. The as-developed novel γ-PGA/nano-HAp paste possesses a high efficacy towards tooth microhardness rehardening, and a protective effect against acid etching.

2002 ◽  
Vol 3 (2) ◽  
pp. 23-30 ◽  
Author(s):  
Güliz Görgül ◽  
A. Cemal Tinaz ◽  
Tayfun Alaçam ◽  
Bağdagül H. Kivanç ◽  
Özgür Uzun

Abstract The aim of this in vitro study was to evaluate the apical and coronal microleakage of a packable composite material compacted by either hand or ultrasonic condensers when placed in post spaces. Fortytwo extracted anterior teeth were used. After conventional obturation of the root canals, parallel post spaces 5 mm in depth and 2 mm in diameter were prepared using Gates Glidden and diamond burs. A primer and a dentin bonding agent (Prime & Bond NT) was applied to the etched surface for 30 seconds and light polymerized for 40 seconds. Surefil packable composite resin was inserted in four equal increments and each polymerized for 40 seconds. Half of the specimens were compacted with an ultrasonic tip and the other half with a mechanical hand compactor. After immersion in the dye, the teeth were sectioned longitudinally and dye penetration was evaluated using a stereomicroscope and microleakage recorded in mm. A One-Way Analysis of Variance indicated the two condensing methods were not statistically different (p>0.05). When microleakage was compared within groups, there was also no statistical difference between coronal or apical microleakage (p>0.05). In an in vitro environment, ultrasonic condensers do not offer any advantage over hand condensers. Both the coronal and apical portions of the root had microleakage indicating that regardless of the condensation method and the use of a packable composite, there is still microleakage that could potentially create further clinical problems. Citation Görgül G, Alaçam T, Kivanç BH, et. al. Microleakage of Packable Composites Used in Post Spaces Condensed Using Different Methods. J Contemp Dent Pract 2002 May;(3)2: 023-030.


2015 ◽  
Vol 83 ◽  
pp. 151-163 ◽  
Author(s):  
Loganathan Gayathri ◽  
Rajakumar Dhivya ◽  
Dharumadurai Dhanasekaran ◽  
Vaiyapuri S. Periasamy ◽  
Ali A. Alshatwi ◽  
...  

1998 ◽  
Vol 22 (4) ◽  
pp. 348-352 ◽  
Author(s):  
Koji Kawahito ◽  
Akio Fujimura ◽  
Eiji Kobayashi ◽  
Yoshio Misawa ◽  
Katsuo Fuse

2020 ◽  
Author(s):  
Yue-zhi Zhang ◽  
Shu-jing Ge ◽  
Qing-zhen Leng ◽  
Jian-jun Ma ◽  
Hanchen Liu

Abstract Background: This study aimed to confirm the cytotoxicity of zymosan in AHH-1 cells and HIECs and to determine the treatment time and dose of zymosan at which it exerts radioprotective effects.Methods: AHH-1 cells and HIECs were administered 0, 20, 40, 80 or 160 μg/mL zymosan. The CCK-8 assay and flow cytometry were used to evaluate cell viability and apoptosis 24 h, 48 h, and 72 h after administration. Furthermore, 12 h before irradiation, the cells were treated with 0, 5, 10, or 20 μg/mL zymosan and then irradiated with 4 Gy X-rays. Cell viability and apoptosis were measured by the CCK-8 assay and flow cytometry at 24 h. In addition, the protective effect of zymosan against radiation in vitro was compared to that of 20 μg/mL LPS as a positive control. In vivo, weight, the spleen index and the thymus index were measured to evaluate the toxicity of 0, 5, 10, 20 and 10 mg/kg zymosan. In addition, rats were treated with 0, 2, 4, 8 or 10 mg/kg zymosan and then irradiated with 7 Gy X-rays. The survival rate, spleen index and thymus index were evaluated. The protective effect of zymosan against radiation in vivo was compared to that of 10 mg/kg LPS a positive control. Results: The viability and apoptosis of cells treated with different doses of zymosan for different treatment times were not different from those of control cells (p<0.05). Furthermore, cell viability and apoptosis were clearly improved after zymosan preadministration (p<0.05). The radioprotective effect of zymosan was dose-dependent. In addition, the viability of cells pretreated with zymosan was higher than that of cells pretreated with LPS, and the apoptosis rate of zymosan-treated cells was lower than that of cells pretreated with LPS (p<0.05). In vivo, weight, the spleen index and the thymus index were significantly decreased by zymosan at a concentration of 20 mg/kg (p<0.05). Further experiments showed that the concentration at which zymosan exerted radioprotective effects was 10 mg/kg. The radioprotective effect of zymosan was better than that of LPS pretreatment (p<0.05). Conclusion: Zymosan is nontoxic to cells and exerts a better radioprotective effect than LPS.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Tripti Thapa Gupta ◽  
Surya B. Karki ◽  
Jyl S. Matson ◽  
Daniel J. Gehling ◽  
Halim Ayan

Nosocomial infections caused by opportunistic bacteria pose major healthcare problem worldwide. Out of the many microorganisms responsible for such infections,Pseudomonas aeruginosais a ubiquitous bacterium that accounts for 10–20% of hospital-acquired infections. These infections have mortality rates ranging from 18 to 60% and the cost of treatment ranges from $20,000 to $80,000 per infection. The formation of biofilms on medical devices and implants is responsible for the majority of those infections. Only limited progress has been made to prevent this issue in a safe and cost-effective manner. To address this, we propose employing jet plasma to break down and inactivate biofilmsin vitro. Moreover, to improve the antimicrobial effect on the biofilm, a treatment method using a combination of jet plasma and a biocide known as chlorhexidine (CHX) digluconate was investigated. We found that complete sterilization ofP. aeruginosabiofilms can be achieved after combinatorial treatment using plasma and CHX. A decrease in biofilm viability was also observed using confocal laser scanning electron microscopy (CLSM). This treatment method sterilized biofilm-contaminated surfaces in a short treatment time, indicating it to be a potential tool for the removal of biofilms present on medical devices and implants.


2019 ◽  
Vol 53 (4) ◽  
pp. 457-466 ◽  
Author(s):  
Kevin R. Sieber ◽  
Christoph Schmidt ◽  
Tommy Baumann ◽  
Adrian Lussi ◽  
Thiago S. Carvalho

Casein and mucin have been shown to improve the erosion-protective properties of the pellicle when applied in combination. The aim of this in vitro study was to optimize the concentrations of these 2 proteins to achieve a maximum protective effect. For the 2 parts of this study, we prepared a total of 195 human enamel specimens and randomly assigned them to 13 groups, corresponding to 11 different casein-mucin concentration-combinations tested and 2 negative control groups (humid chamber). They underwent 5 cycles, consisting of pellicle formation from human whole saliva (2 h, 30°C), modification of the pellicle with casein and mucin in different concentrations (immersion in protein solutions for 2 h, 30°C), and erosion for 1 min in citric acid (0.65%, pH 3.5, 30°C). Surface microhardness (SMH), surface reflection intensity (SRI), and in the first part also calcium release were monitored during the cycling process, and analyzed with Kruskal-Wallis and post hoc Dunn’s tests. The results suggest that the best concentrations to achieve the highest erosion-protective effect are 3.0% casein and 0.81% mucin, which lead to a significant protection as measured by SMH as well as SRI compared to the unmodified pellicle. For the calcium release, no significant differences were found. This concentration combination corresponds to a general raise of the protein concentrations and a change in the molar ratio of the proteins as compared to earlier studies. Casein and mucin could now be incorporated at the determined concentration as natural ingredients in oral care products designed to protect against erosion.


Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3279
Author(s):  
Javier Moyano ◽  
Laia Mases ◽  
Telmo Izeta ◽  
Teresa Flores ◽  
Javier Fernández-Bozal ◽  
...  

Many advantages have been described surrounding self-ligating (SL) brackets compared to metallic conventional ligating (CL) brackets, such as: Less total treatment time, alignment efficiency, patient comfort, plaque retention, and low friction. The objective of this in vitro simulation was to know the variables that affect arch displacement in CL and SL brackets—active (ASL) and passive (PSL)—and analyze if static friction values are affected by bracket design, arch wire section, kind of ligature, and use of a friction reducer agent (FRA) in a wet state. Larger values of static friction were found in CL with metallic ligature (ML) (8.01 ± 1.08 N/mm) and elastic ligature (EL) (6.96 ± 0.48 N/mm). Lower values were found in PSL brackets combined with FRA (0.58 ± 0.21 N/mm). The study was carried out using different stereographical models of a maxillary upper right quadrant with canine, first and second premolar, and first molar bonded brackets. A section of 25 mm of 0.019 × 0.025” stainless steel arch with a rectangular section (SS) and hybrid section (HY) was inserted into the different bracket models. Static friction values were collected using a universal test machine in wet conditions and testing the effect of a friction reducer agent (FRA). To assure the reliability of the study, different wire combinations were repeated after two weeks by the same operator and a linear analysis of regression was done. Each bracket model analysis—with the different wires, use of the FRA, and comparison among brackets in similar conditions—was done using an ANOVA test with a confidence interval of 95% and comparative Post-Hoc tests (LSD). In this in vitro simulation we found higher static friction values in CL compared to ASL and PSL. In PSL, lower values were achieved. CL brackets using ML showed the highest static friction values with a great variability. In this setting, the use of HY wires did not reduce static friction values in ASL and PSL, while in CL brackets with EL friction the values were reduced significantly. An FRA combined with ASL reduced significantly static friction values but not with PSL. In the case of CL, the FRA effect was higher with SS and better than with HY wires. ML values were similar to ASL static friction. The direct extrapolation of the results might be inaccurate, since all these findings should be tested clinically to be validated.


2020 ◽  
Vol 135 ◽  
pp. 110900 ◽  
Author(s):  
Lorenzo Rivas-García ◽  
José L. Quiles ◽  
Alfonso Varela-López ◽  
Miguel Arredondo ◽  
Paulina Lopez ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Heng-feng Yuan ◽  
Jian-feng Pan ◽  
Shuo Li ◽  
Chang-an Guo ◽  
Shu-hao Liu ◽  
...  

This research was designed to investigate the protective effects of TSPN on steroid-induced avascular necrosis of the femoral head (ANFH) and the likely mechanisms of those effects. As an in vivo study, TSPN was shown to be protective against steroid-induced ANFH due to the upregulation of VEGF-A. Furthermore, TSPN attenuated the apoptosis of osteocytes and reduced the expression of Caspase-3 relative to the model group. As an in vitro study, TSPN exerted a concentration-dependent protective effect against apoptosis in MC3T3-E1 cells. Moreover, TSPN (at a dose of 100 μg/mL) significantly reversed the dexamethasone-induced augmentation of Caspase-3 expression and activity. Therefore, our study demonstrated that TSPN had a protective effect against steroid-induced ANFH that was related to the upregulation of VEGF-A and the inhibition of apoptosis and Caspase-3 activation.


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