• The korean journal of orthodontics
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• v.53 no.2
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• pp.89-98
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• 2023

Objective: This study aimed to compare the mechanical and thermal properties in the anterior and posterior segments of new and retrieved specimens of a commercially available multizone superelastic nickel-titanium (NiTi) archwire. Methods: The following groups of 0.016 × 0.022-inch Bioforce NiTi archwires were compared: a) anterior and b) posterior segments of new specimens and c) anterior and d) posterior segments of retrieved specimens. Six specimens were evaluated in each group, by three-point bending and bend and free recovery tests. Bending moduli (Eb) were calculated. Furthermore, the new specimens were evaluated with scanning electron microscopy/energy-dispersive X-ray spectrometry. A multiple linear regression model with a random intercept at the wire level was applied for data analysis. Results: The forces in the posterior segments or new specimens were higher than those recorded in the anterior segments or retrieved specimens, respectively. Accordingly, Eb also varied. Higher austenite start and austenite finish (Af) temperatures were recorded in the anterior segments. No statistically significant differences were found for these temperatures between retrieved and new wires. The mean elemental composition was (weight percentage): Ni, 52.6 ± 0.5; Ti, 47.4 ± 0.5. Conclusions: The existence of multiple force zones was confirmed in new and retrieved Bioforce archwires. The retrieved archwires demonstrated lower forces during the initial stages of deactivation in three-point bending tests, compared with new specimens. The Af temperature of these archwires may lie higher than the regular intraoral temperature. Even at 2 mm deflections, the forces recorded from these archwires may lie beyond biologically safe limits.

• The korean journal of orthodontics
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• v.52 no.2
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• pp.123-130
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• 2022

Objective: To evaluate if a remote digital monitoring system added at the end of orthodontic treatment could positively influence the retention phase by reducing the occurrence of misfit of removable appliances, number of emergency appointments (EA), and orthodontic relapse. Methods: Twenty-seven patients who completed active orthodontic treatment were divided into the study and control groups. In addition to the standard chairside follow-up appointments at month 1 (T1), month 3 (T2), month 6 (T3), the study group patients were monitored using Dental Monitoring^® with monthly intra-oral scans. Occurrence of misfit of removable retainers, number of EAs, and intercanine width change were recorded for both groups. Differences in EAs and retainer fit were assessed using the chi-square test. Intra-group and inter-group differences in the intercanine width were assessed with Friedman test and Mann-Whitney U test, respectively (α = 0.05). Results: The study group showed a significantly lower occurrence of misfit of removable retainers (p = 0.027) compared to the control group. No significant inter- and intra-group difference was found in the EAs and intercanine width change at each time-point. Conclusions: Integrating remote monitoring systems, such as Dental Monitoring^®, to the retention phase of the orthodontic treatment may lower the occurrence of misfit of removable retainers. However, a small sample size and a short observation period limit the strength of this evidence. These preliminary results tentatively suggest that remote monitoring technologies may be beneficial, especially during the COVID-19 pandemic, when the regularity of in-office visits might be disrupted.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.2
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• pp.210-219
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• 2017

This study aimed to investigate the prevalence and distribution of enamel hypomineralization, including molar-incisor hypomineralization (MIH), among adolescents and assess their correlation with esthetic satisfaction. A total of 1371 adolescents between the ages of 14 and 16 years in Yangsan city were evaluated for enamel hypomineralization, including MIH, according to the European Academy of Paediatric Dentistry (EAPD) criteria. In a parallel survey, esthetic satisfaction about anterior teeth and its correlation with incisor enamel hypomineralization were analyzed. The prevalence of MIH was 13.8% (n = 189), while that of hypomineralization in any permanent tooth was 23.2% (n = 318), which was substantially greater compared to the national prevalence of MIH. Mandibular first molars exhibited the highest prevalence of hypomineralization, followed by maxillary central incisors and mandibular second molars. Among anterior teeth, the most frequently affected site was the incisal edge of maxillary central incisors. A high degree of hypomineralization in anterior teeth was associated with a high demand for esthetic treatment.

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1167-1173
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• 2006

Purpose : To evaluate various sepsis screening tests, individually and in combination, to formulate a guideline for the diagnosis of neonatal sepsis. Methods : The study was a retrospective cohort study. It took place at the neonatal intensive care unit of the Paediatric Department, Il Sin Christian Hospital, Busan, Korea, over a period of 68 months from 1st, April, 2001 to 31st, December, 2005. This study evaluated 100 neonates having clinical features of sepsis and 100 normal asymptomatic neonates and used screening tests including C-reactive protein (CRP), total leukocyte count (TLC), absolute neutrophil count (ANC), immature neutrophils to total neutrophil count ratio (I/T ratio), thrombocytopenia, degenerative changes in the neutrophils and gastric aspirate cytology (GAC) for the diagnosis of neontal sepsis. Results : The sensitivity of CRP and ANC was high. CRP had 86 percent sensitivity for group-A (proven sepsis) and 74 percent sensitivity for group-B (probable sepsis) and 94 percent specificity for group-A, B. ANC had sensitivity of 72 percent for group-A and 62 percent for group-B and 86 percent specificity for group-A, B. For group-A, sensitivity, specificity of GAC for polymorphs was 74 percent and 94 percent respectively. As for sensitivity, specificity of platelet count for group-A was 64 percent and 89 percent respecively. The sensitivity, specificity and predictive values (PV) of the individual tests and different test combinations were also calculated for group-A and B. Conclusion : For the detection of culture negative cases in neonatal sepsis, screening tests including CRP, TLC, ANC, thrombocytopenia, cytoplasmic vacuolization in the neutrophils and GAC for polymorphs have high sensitivity. A combination of three tests has higher sensitivity.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.1
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• pp.93-118
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• 2014

The Korean Academy of Pediatric Dentistry hosted the $24^{th}$ IAPD Congress in Seoul, Korea on June 12-15, 2013. The main theme of the congress was the "New visions in Pediatric Dentistry" A total number of 1,855 participants, including exhibitors and press from 67 countries, participated in the 24th IAPD Congress. The scientific program consists of 85 invited lectures, 126 oral presentations, and 553 poster presentations. 46 companies and organizations have supported and participated in Seoul IAPD Congress. Overall the congress was a success in terms of high attendance rate from 67 countries over the world. Considering the fact that Korea is located in the far-east, the number of overseas delegates(943) are remarkable. Also it is desirable to have over 100 delegates from developing countries which eventually aim to collaborate worldwide. The scientific program covered a variety of topics and many of the delegates stayed in the session room until the last day of the congress. Although it could have been more beneficial to allot more time for each speaker to discuss further, the program fit the Congress theme "New Visions for Paediatric Dentistry". All social event tickets were sold out early and it attracted participants with interesting program enabling participants to interact and exchange ideas outside of the meeting.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4583-4589
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• 2013

Objective: This study aimed to investigate the effect of multimodality treatment of advanced paediatric hepatoblastoma (HB) and the factors affecting prognosis. Methods: A total of 35 children underwent multimodality treatments consisting of chemotherapy, surgery, interventional therapy, and autologous peripheral blood stem cell transplantation. The patients were followed up every month. Results: Serum AFP levels in 33 out of 35 patients in this study were significantly increased (P = 0.0002). According to the statistical scatter plot, the values of serum AFP on the 25th, 50th, and 75th percentages were 1,210, 1,210 and 28,318 ng/dl, respectively. Of the 35 cases, 21 were stage IV. 18 cases were treated with systemic chemotherapy before surgery, and 3 cases with locally interventional chemotherapy before surgery. Statistical analysis showed that the preferred interventional treatment affected prognosis, and that there was a statistically significant difference (P = 0.024). Some 33 patients completed the follow-up, of which 17 were in complete remission (CR), 5 were in partial remission (PR), 1 became disease progressive (DP), and 10 died. The remission and overall survival rates were 66.7% (22/33) and 69.7% (23/33), respectively. Patients with the mixed HB phenotypes had worse prognoses than the epithelial phenotype (P < 0.001), and patients in stage IV had a lower survival rate than those in stage III (P < 0.001). Conclusion: Multimodality treatment can effectively improve remission rate and prolong the survival of children with advanced HB. In addition, alpha-fetoprotein (AFP), a tumor marker of liver malignant tumors, HB pathological classification, and staging are highly useful in predicting prognosis.