• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.405-413
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• 2021

The purpose of this in vivo study was to assess the clinical screening performance of a quantitative light-induced fluorescence (QLF) device in detecting proximal caries in primary molars. Fluorescence loss, red autofluorescence and a simplified QLF score for proximal caries (QS-proximal) were evaluated for their validity in detecting proximal caries in primary molars compared to bitewing radiography. Three hundred and forty-four primary molar surfaces were included in the study. Carious lesions were scored according to lesion severity assessed by visual-tactile and radiographic examinations. The QLF images were analyzed for two quantitative parameters, fluorescence loss and red autofluorescence, as well as for QS-proximal. For both quantitative parameters and QS-proximal, the sensitivity, specificity and area under receiver operating curve (AUROC) were calculated as a function of the radiographic scoring index at enamel and dentin caries levels. Both quantitative parameters showed fair AUROC values for detecting dentine level caries (△F = 0.794, △R = 0.750). QS-proximal showed higher AUROC values (0.757 - 0.769) than that of visual-tactile scores (0.653) in detecting dentine level caries. The QLF device showed fair screening performance in detecting proximal caries in primary molars compared to bitewing radiography.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.5
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• pp.339-348
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• 2022

Background: To compare the anesthetic efficacy of supplemental buccal infiltration (BI) (1.7 ml) versus intraligamentary (IL) injection containing 0.4 ml of 4% articaine with 1:100.000 epinephrine after an inferior alveolar nerve block (IANB) with 1.7 ml 2% lidocaine in the first and second mandibular molars diagnosed with irreversible pulpitis (IP). Methods: One hundred subjects diagnosed with IP of either the mandibular first (n = 50) or second molars (n = 50) and failed profound anesthesia following an IANB were selected. They randomly received either the IL or BI techniques of anesthesia. Pain scores on a 170 mm Heft-Parker visual analog scale were recorded initially, before, and during supplemental injections. Furthermore, pulse rate was measured before and after each supplemental injection. During the access cavity preparation and initial filing, no or mild pain was assumed to indicate anesthetic success. The chi-square test, Mann-Whitney U test, and independent samples t-test were used for the analyses. Results: The overall success rates were 80% in the IL group and 74% in the BI group, with no significant difference (P = 0.63). In the first molars, there was no significant difference between the two techniques (P = 0.088). In the second molars, IL injection resulted in a significantly higher success rate (P = 0.017) than BI. IL injection was statistically more successful (P = 0.034) in the second molars (92%) than in the first molars (68%). However, BI was significantly more successful (P = 0.047) in the first molars (88%) than in the second molars (64%). The mean pulse rate increase was significantly higher in the IL group than in the BI group (P < 0.001). Conclusions: Both the IL and BI techniques were advantageous when used as supplemental injections. However, more favorable outcomes were observed when the second molars received IL injection and the first molars received BI.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.15-22
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• 2023

Recent studies have actively investigated ways to improve the economic feasibility and efficiency of the Fischer-Tropsch process by increasing the yields of the monocyclic aromatic compounds (BTEX). In this study, ethylene was selected as a model of F-T-derived hydrocarbons, and the ethylene-to-aromatics (ETA) reaction was investigated according to changes in acid characteristics, mesopores, and crystallinity of HZSM-5 (HZ5). Fluorinated HZ5 was prepared by calcination followed by impregnation of an aqueous NH₄F solution having different molar concentrations in HZ5, and the structural and chemical properties of F/HZ5 were investigated through Brunauer-Emmett-Teller (BET), solid-state nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), NH₃-temperature-programmed desorption (TPD), and pyridine-IR spectroscopy. The ETA reactions were performed at 673 K under 0.1 MPa, and fluorinating HZ5 by an aqueous NH₄F solution of 0.17 M improved ethylene conversion, BTEX selectivity, and catalytic stability due to acidity, mesopore fraction, and crystallinity.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.170-179
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• 2022

This study aimed to evaluate the masticatory performance of Korean children and adolescents and to investigate related factors. Early loss of primary molars, degree of occlusion of first molars, occlusal relationship of first molars, and presence of anterior crossbite were considered. From March 2020 to July 2021, 56 children and adolescents between the ages of 6 and 12 were included. The mixing ability index (MAI) was calculated to evaluate the masticatory efficiency of children and adolescents. The subjects were classified into three groups according to the number of early lost primary molars; normal dentition, 1 - 2 teeth lost, more than 3 teeth lost. The number of participants are 23, 18, and 15, respectively. There was no difference in the MAI values between the normal dentition group and the group has 1 - 2 teeth lost. However, when 3 or more primary molars were lost, the MAI value decreased and a significant difference was observed. This study is the first study to evaluate the masticatory performance of children and adolescents in Korea, and it will be helpful to pediatric dentists who evaluate the masticatory performance of children and adolescents and strive to improve the masticatory efficiency of children and adolescents in clinical practice.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.95-103
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• 2022

The first permanent molars play a key role in maxillofacial development and occlusion. The purpose of this study is to investigate the characteristics and development stages of first molars with delayed eruption, and to evaluate their associations with congenital missing teeth. Eight-year-old patients who had delayed eruption in their first molars were classified into 75 patients with physical barriers and 77 patients without physical barriers. The development stages of the first and second molars in the delayed area were analyzed using Nolla method from the panoramic radiographs. The relationship between congenital missing teeth and delayed area was also investigated. Delayed eruption of first molars were more common in the maxilla alone. With the presence of physical barriers, male patients showed higher frequency in unilateral cases, while female patients had higher bilateral cases when there was no physical barrier. Delayed development of first molars were observed in delayed eruption area. In the absence of physical barriers, adjacent second molars were also developed slowly and the incidence of congenital missing teeth was high in delayed area. If first molars with delayed eruption are observed, clinical and radiographical follow-ups are necessary for the evaluation of their developmental stages and congenital missing teeth.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.179-187
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• 2022

In this study, the synthesis of 1,2-dodecylaminopropanediol (1,2-DDAP) having a 12 carbon chain length and an amine group was designed to improve the preservation and hydrophilicity of 1,2-alkanediol-based compounds. 1,2-DDAP was prepared by reacting dodecylamine (DDA) with 3-monochloro-1,2-propanediol (3-MCPD) in an ethanol solvent at 40 ℃, and its yield and purity were about 56% and 98%, respectively, under a reaction condition of 2 h and a DDA:3-MCPD molar ratio of 1:0.8. The antimicrobial effect of 1,2-DDAP showed the values of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against microorganisms at concentrations of 10 to 100 times lower than those of 1,2-octanediol(1,2-ODIOL) or 1,2-decanediol (1,2-DDIOL). Based on the hydrophilic properties of 1,2-DDAP, mixed preservatives were prepared by adding small amounts of 1,2-ODIOL or 1,2-DDIOL, which are poorly soluble in water, with 1,2-DDAP. Mixed preservatives exhibited an effect of inhibiting microorganisms equal to or greater than that of 1,2-DDAP alone in antimicrobial activity tests. As a result of confirming the preservation effect in lotion (cosmetic formulation) for application, 1,2-DDAP showed similar antimicrobial activity at concentrations of 0.3 to 0.6 times lower than that of 1,2-ODIOL or 1,2-DDIOL. Therefore, it is considered that the use of 1,2-DDAP alone and the mixed use with small amounts of 1,2-ODIOL or 1,2-DDIOL can be a good alternative to preservatives in the product.

• The Journal of Advanced Prosthodontics
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• v.14 no.4
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• pp.203-211
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• 2022

PURPOSE. The aim of this study was to introduce rating criteria to evaluate student performance in a newly developed, digital wax-up preclinical program for computer-aided design (CAD) of full-coverage crowns and preliminarily investigate the reliability and internal consistency of the rating system. MATERIALS AND METHODS. This study, conducted in 2017, enrolled 47 fifth-year dental students of Okayama University Dental School. Digital wax-up training included a fundamental practice using computer graphics (CG), multipurpose CAD software programs, and an advanced practice to execute a digital wax-up of the right mandibular second molar (#47). Each student's digital wax-up work (stereolithography data) was evaluated by two instructors using seven qualitative criteria. The total qualitative score (0-90) of the criteria was calculated. The total volumetric discrepancy between each student's digital wax-up work and a reference prepared by an instructor was automatically measured by the CAD software. The inter-rater reliability of each criterion was analyzed using a weighted kappa index. The relationship between the total volume discrepancy and the total qualitative score was analyzed using Spearman's correlation. RESULTS. The weighted kappa values for the seven qualitative criteria ranged from 0.62 - 0.93. The total qualitative score and the total volumetric discrepancy were negatively correlated (ρ = -0.27, P = .09, respectively); however, this was not statistically significant. CONCLUSION. The established qualitative criteria to evaluate students' work showed sufficiently high inter-rater reliability; however, the digitally measured volumetric discrepancy could not sufficiently predict the total qualitative score.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.307-317
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• 2023

Due to increasing demand for aesthetics, zirconia crowns have become a popular choice for treating primary molars. However, there is limited literature available comparing the survival rates of zirconia crowns with those of other restorative materials. The objective of this study was to compare the 36-month survival rates of zirconia crowns and stainless steel crowns for proximal caries, as well as to analyze failure types associated with each crown type. Electronic medical records and radiographs of 1,061 primary molars from 498 patients treated with 2 types of prefabricated crowns at Chosun University Dental Hospital and 2 private dental clinics between 2017 and 2019 were collected and analyzed. The survival rate of zirconia crowns was found to be lower compared to that of stainless steel crowns. Regarding the groups without pulp treatment, the survival rate of stainless steel crowns was significantly higher than that of zirconia crowns. However, in the groups that received pulp therapy, no significant difference in the survival rates was observed between the two preformed crowns. Notably, abnormal root resorption or periapical lesions were identified as the primary cause of restorative failure in stainless steel crowns, whereas loss of restoration was the predominant cause in zirconia crowns. This study holds valuable implications for clinicians when selecting preformed crowns for primary molars.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.620-629
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• 2022

By varying various experimental conditions such as heating rate, molar hourly space velocity (MHSV), and nitridation reaction temperature, vanadium oxynitride was prepared through temperature programmed reduction/nitridation reaction (TPRN) of vanadium pentoxide and ammonia, and characterization were performed. In order to investigate the physico-chemical properties of the prepared catalyst, N₂ adsorption-desorption analysis, X-ray diffraction analysis (XRD), hydrogen temperature programmed reduction (H₂-TPR), temperature programmed oxidation (TPO), ammonia temperature programmed desorption (NH₃-TPD), transmission electron microscopy (TEM) was performed. Transformation of V₂O₅ with 5 m² g^-1 low specific surface area by reduction at 340 ℃ to V₂O₃ showed a high specific surface area value of 115 m² g^-1 by micropore formation. As the nitridation temperature increased beyond that, the specific surface area continued to decrease due to sintering. The nitridation reaction variable that had the greatest influence on the specific surface area was the reaction temperature, and the x + y value of VN_xO_y of a single phase approached from 1.5 to 1.0 as the nitridation reaction temperature increased. At a high reaction temperature of 680 ℃, the cubic lattice constant a was VN. close to the value. At 680 ℃, the highest nitridation temperature among the experimental conditions, the ammonia conversion rate was 93%, and no deactivation was observed.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.3
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• pp.163-171
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• 2023

Background: Surgical extraction of impacted mandibular third molars is the most common procedure performed by oral surgeons. The procedure cannot be performed effectively without achieving profound anesthesia. During this procedure, patients may feel pain during surgical bone removal (at the cancellous level) or during splitting and luxation of the tooth, despite administration of routine nerve blocks. Administration of intraosseous (IO) lignocaine injections during third molar surgeries to provide effective anesthesia for pain alleviation has been documented. However, whether the anesthetic effect of lignocaine is the only reason for pain alleviation when administered intraosseously remains unclear. This conundrum motivated us to assess the efficacy of IO normal saline versus lignocaine injections during surgical removal of impacted mandibular third molars. The aim of this study was to assess the efficacy of IO normal saline as a viable alternative or adjunct to lignocaine for alleviation of intraoperative pain during surgical removal of impacted mandibular third molars. Methods: This randomized, double-blind, interventional study included 160 patients who underwent surgical extraction of impacted mandibular third molars and experienced pain during surgical removal of the buccal bone or sectioning and luxation of the tooth. The participants were divided into two groups: the study group, which included patients who would receive IO saline injections, and the control group, which included patients who would receive IO lignocaine injections. Patients were asked to complete a visual analog pain scale (VAPS) at baseline and after receiving the IO injections. Results: Of the 160 patients included in this study, 80 received IO lignocaine (control group), whereas 80 received IO saline (study group) following randomization. The baseline VAPS score of the patients and controls was 5.71 ± 1.33 and 5.68 ± 1.21, respectively. The difference between the baseline VAPS scores of the two groups was not statistically significant (P > 0.05). The difference between the numbers of patients who experienced pain relief following administration of IO lignocaine (n=74) versus saline (n=69) was not statistically significant (P > 0.05). The difference between VAPS scores measured after IO injection in both groups was not statistically significant (P >0.05) (1.05 ± 1.20 for the control group vs. 1.72 ± 1.56 for the study group) Conclusion: The study demonstrates that IO injection of normal saline is as effective as lignocaine in alleviating pain during surgical removal of impacted mandibular third molars and can be used as an effective adjunct to conventional lignocaine injection.