• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.33.1-33.12
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• 2023

Objectives: This study aimed to evaluate the bleaching efficacy and hydrogen peroxide permeability in the pulp chamber by the at-home bleaching gel in protocols applied on different dental surfaces. Materials and Methods: Forty premolars were randomly into 4 groups: control group no bleaching, only application on the buccal surface (OB), only application on the lingual surface (OL) and application in buccal and lingual surfaces, simultaneously (BL). At-home bleaching gel (White Class 7.5%) was used for the procedure. The bleaching efficacy was evaluated with a digital spectrophotometer (color change in CIELAB [ΔE_ab] and CIEDE 2000 [ΔE₀₀] systems and Whitening Index for Dentistry [ΔWI_D]). The hydrogen peroxide permeability in the pulp chamber (㎍/mL) was assessed using UV-Vis spectrophotometry and data were analyzed for a 1-way analysis of variance and Tukey's test (α = 0.05). Results: All groups submitted to bleaching procedure showed bleaching efficacy when measured with ΔE_ab and ΔE₀₀ (p > 0.05). Therefore, when analyzed by ΔWI_D, a higher bleaching efficacy were observed for the application on the groups OB and BL (p = 0.00003). Similar hydrogen peroxide permeability was found in the pulp chambers of the teeth undergoing different protocols (p > 0.05). Conclusions: The application of bleaching gel exclusively on the OB is sufficient to achieve bleaching efficacy, when compared to BL. Although the OL protocol demonstrated lower bleaching efficacy based on the ΔWI_D values, it may still be of interest and relevant in certain clinical scenarios based on individual needs, requiring clinical trials to better understand its specificities.

• Restorative Dentistry and Endodontics
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• v.49 no.2
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• pp.15.1-15.11
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• 2024

Objectives: This study aimed to establish a single-session associative protocol for nonrestorative management of dentin hypersensitivity (DH). Materials and Methods: Twenty-four individuals with DH and a minimum sensitivity level of 4 on the visual analog scale (VAS) were selected. The study was conducted in a split-mouth design, with each participant (n = 20) having at least 1 affected tooth in all quadrants. The management protocols consisted of control group: universal adhesive, Neural Desensitizing Protocol group: 5% potassium nitrate, Mixed Desensitizing Protocol (PAM) group: 5% sodium fluoride and 5% potassium nitrate, Remineralizing Desensitizing Protocol (PDR) group: surface-partially reacted glass technology photopolymerizable varnish. Evaluations were performed immediately after application, at 1 week, 1 month, 2 months, and 12 months using the VAS sensitivity test. Results: The scores were subjected to statistical analysis using the Friedman test (p < 0.05), Durbin-Conover test (p < 0.05), and Wilcoxon test (p < 0.05). At the 12-month evaluation, all groups showed statistically significant differences compared to the initial assessment. For the evaluation after 12 months, there was a statistically significant difference between the PAM group, the control group, and the PDR group. Conclusions: It can be concluded that all groups were effective in controlling DH, but there were significant results in the control group and PDR group. The clinical relevance of this study is to demonstrate that the application of single-session desensitizing protocols can be effective in controlling DH for up to 12 months.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.14.1-14.2
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• 2022

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.197-205
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• 2022

This study was conducted to investigate the fluoride release of fluoride-containing restorative materials in fluoride recharging according to the concentration of fluoride toothpaste used in Korea. Samples of glass ionomer cement, resin-modified glass ionomer cement, alkasite restorative material, and composite resin were prepared and fluoride release was measured on days 1, 3, 7, 14, 21, 28. Thereafter, fluoride-free, 500 ppm, and 1450 ppm fluoride toothpaste was applied to each restorative materials, and the fluoride release was measured on days 1, 3, 7. Glass ionomer cement showed the highest cumulative fluoride release until the 7th day of measurement, and from the 14th day onwards, the resin-modified glass ionomer cement showed the highest cumulative fluoride release, but there was no significant difference. When restorative material groups were recharged with 500 ppm of fluoride toothpaste, the fluoride release was significantly higher only for the alkasite restorative material compared to the fluoride-free toothpaste group (p < 0.017). When restorative material groups were recharged with 1450 ppm of fluoride toothpaste, the fluoride release was significantly higher in all restorative groups compared to the fluoride-free toothpaste group (p < 0.017).

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.21.1-21.12
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• 2021

Objectives: This study compared the cytotoxicity, biocompatibility, and tenascin immunolabeling of a new ready-to-use hydraulic sealer (Bio-C Sealer) with MTA-Fillapex and white MTA-Angelus. Materials and Methods: L929 fibroblasts were cultivated and exposed to undiluted and diluted material extracts. Polyethylene tubes with or without (the control) the materials were implanted into the dorsa of rats. At 7 days and 30 days, the rats were euthanized, and the specimens were prepared for analysis; inflammation and immunolabeling were measured, and statistical analysis was performed (p < 0.05). Results: MTA-Fillapex exhibited greater cytotoxicity than the other materials at all time points (p < 0.05). The undiluted Bio-C Sealer exhibited greater cytocompatibility at 6 and 48 hours than white MTA-Angelus, with higher cell viability than in the control (p < 0.05). White MTA-Angelus displayed higher cell viability than the control at 24 hours, and the one-half dilution displayed similar results at both 6 and 48 hours (p < 0.05). At 7 days and 30 days, the groups exhibited moderate inflammation with thick fibrous capsules and mild inflammation with thin fibrous capsules, respectively (p > 0.05). At 7 days, moderate to strong immunolabeling was observed (p > 0.05). After 30 days, the control and MTA-Fillapex groups exhibited strong immunolabeling, the white MTA-Angelus group exhibited moderate immunolabeling (p > 0.05), and the Bio-C Sealer group exhibited low-to-moderate immunolabeling, differing significantly from the control (p < 0.05). Conclusions: Bio-C Sealer and white MTA-Angelus exhibited greater cytocompatibility than MTA-Fillapex; all materials displayed adequate biocompatibility and induced tenascin immunolabeling.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.39.1-39.23
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• 2023

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

• Journal of the korean academy of Pediatric Dentistry
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• v.3 no.1
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• pp.33-39
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• 1976

The present in vitro study was undertaken to evaluate the initial marginal sealing ability of the sealant known as Nuva-Seal to seal cavity margins when used in conjunction with Adaptic and Nuva-Fil restorative materials. The results were as follows; 1. Where each Adaptic and Nuva-Fil restorative material was filled, showed the greatest degree of marginal leakage. 2. Where Adaptic and Nuva-Fil restorative materials were filled after acid etched surrrounding enamel surface adjoining the cavity margins, showed some degree of marginal leakage. 3. Where the Nuva-Seal was applied after acid etching a) to the cavity walls and the peripheral enamel surface adjoining the cavity margins, b) only to the surrounding enamel surface adjoining the cavity margins, and c) over the restorations and the peripheral enamel surface, showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials. 4. Where the Nuva-Seal was applied with the same methods as above, and restorations were placed on thermal stress also showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.305-308
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• 2005

The sulfuric acid may react with the hardened cement paste and originate expansive products which can induce swelling and disaggregation of concrete. The purpose of this study is to estimate the antibacterial performance of antibiotics and the effect of absorbed condition of restorative mortar, the number of coating times and coating contents with antibiotic on the fundamental properties of restorative mortar spead with antibiotics. Also, testing items such as bonding strength, abrasion contents, contents of water absorption, contents of air permeability was tested to estimate the fundamental properties in this study. In results, the novellus bacillus inhabiting in sewer concrete structures was restrained by antibiotics developed in this study. And bonding strength of restorative mortar spread with antibiotics was similla to that of plain mortar. But, resistance to abrasion, water absorption and air permeability of restorative mortar spread with antibiotics was superior to that of plain mortar.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.191-196
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• 2010

Power system restoration following a massive or complete blackout starts with energizing the primary restorative transmission system. During this primary restoration process, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. In the case of the Myanmar electric power system, there are so many wide outage experiences, including complete blackout cases, caused by 230kV line faults and so on. Consequently, Myanmar's system operators have been well trained to deal with wide blackouts. Howver, system blackout restoration has been conducted by relying on the experience of only a few specialists. So, more scientific analysis is required to meet the requirements necessary to ensure fast and reliable system restoration. This paper presents analytical results on the primary restorative transmission system of Myanmar, focusing on the problems during the early restoration process. Methodologies are presented that handle load pick-up, terminal voltage and the reactive capability limitation of black-start generators to compensate the Ferranti effect. Static and dynamic simulation with the PSSolution and EMTDC programs respectively for the six cases are performed in order to select the primary restorative transmission lines.

• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.28.1-28.12
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• 2022

Objectives: Metalloproteinase-inhibiting agents, such as chitosan, can prevent collagen degradation in demineralized dental substrates, thereby improving the adhesive interface. This study evaluated the bond strength (BS) and chemical and morphological characterization of the adhesive interface after applying chitosan solution to demineralized dentin. Materials and Methods: The 80 third molars were selected. Forty teeth underwent caries induction using the pH cycling method. The teeth were divided according to the treatment: distilled water (control) and 2.5% chitosan solution. The surfaces were restored using adhesive and composite resins. Half of the specimens in each group were aged, and the other half underwent immediate analyses. The teeth were sectioned and underwent the microtensile bond strength test (µTBS), and chemical and morphological analyses using energy-dispersive spectroscopy and scanning electron microscopy, respectively. Data analysis was performed using 3-way analysis of variance. Results: For µTBS, sound dentin was superior to demineralized dentin (p < 0.001), chitosan-treated specimens had higher bond strength than the untreated ones (p < 0.001), and those that underwent immediate analysis had higher values than the aged specimens (p = 0.019). No significant differences were observed in the chemical or morphological compositions. Conclusions: Chitosan treatment improved bond strength both immediately and after aging, even in demineralized dentin.