Effect of powder-liquid ratios and powder colors on color stability of 4-META / MMA-TBB resin after immersion in coffee

최유리나,장서진,박수정 대한치과재료학회 2018 대한치과재료학회지 Vol.45 No.3

The aim of this study was to evaluate the color stability of 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) resin with different powder-liquid (P/L) ratios and powder colors after immersion in coffee. Experimental groups (Bondfill SB) were classified by the P/L ratio (0.8:1 / 1:1 / 1.2:1, weight [wt] %) and color of the powder (light / medium). Light-cured resin composite (Filtek Z350 XT flowable) was used as a control group. Each disk-shaped specimen of 7 groups (n = 8 for color difference, n = 10 for translucency parameter [TP]) was immersed in a staining solution of coffee for 4 weeks. The color of the specimen was measured at the time of baseline, 1 day, 1 week, 2 weeks, 3 weeks, and 4 weeks with a spectrophotometer. The color difference (ΔE) and changes in translucency parameter (ΔTP) were statistically analyzed by one-way analysis of variance (ANOVA), followed by Tukey’s post-hoc test. Independent t-test was applied to evaluate the effect on the colors of the powder (α = 0.05). The values of color difference (ΔE) of the experimental groups were within the clinically acceptable threshold (ΔE < 3.3), whereas control group showed values over 3.3 after 1 week of immersion. The values of TP ranged from 9.58 to 13.28. The differences of TP (ΔTP) between baseline and 4 weeks were less than 1.0, except in the control group. Conclusively, self-cured resin composite showed excellent color stability in coffee for the period of this study regardless of different P/L ratios and powder colors.

Comparison of polymerization shrinkage of dual-cure core build-up resin according to shade and curing mode

최유리나,Karl Lee,장훈상 조선대학교 치의학연구원 2019 Oral Biology Research (Oral Biol Res) Vol.43 No.4

Polymerization shrinkage of composite resin is closely related to direct or indirect restoration failure. Many studies have reported that curing mode affects polymerization, but few studies have reported whether polymerization shrinkage is affected by the shade of the dual-cure core build-up resin. Therefore, the purpose of this study is to compare the polymerization shrinkage of a dual-cure core build-up resin according to shade and curing mode. A dual-cure core build-up resin (Dual Core, Vericom) was selected and the specimens were prepared using either natural (A3) or blue shade of 6 mm diameter and 0.5 mm thickness. The specimens were either light-cured or self-cured and polymerization shrinkage was measured using a modified bonded disc method for 1,800 seconds (n=7). Polymerization shrinkage data were analyzed using two-way ANOVA and Tukey honestly significant difference at α=0.05. No statistically significant difference in polymerization shrinkage was observed between the natural shade (3.87%±0.31%) and blue shade (3.85%±0.37%). However, polymerization shrinkage in light-curing mode (4.10%±0.14%) was significantly higher than that in selfcuring mode (3.63%±0.31%). In conclusion, polymerization shrinkage of the dual-cure core build-up resin tested in this study was not affected by shade but by curing mode.

Effects of proanthocyanidin, a crosslinking agent, on physical and biological properties of collagen hydrogel scaffold

최유리나,김희진,민경산 대한치과보존학회 2016 Restorative Dentistry & Endodontics Vol.41 No.4

Objectives: The purpose of the present study was to evaluate the effects of proanthocyanidin (PAC), a crosslinking agent, on the physical properties of a collagen hydrogel and the behavior of human periodontal ligament cells (hPDLCs) cultured in the scaffold. Materials and Methods: Viability of hPDLCs treated with PAC was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The physical properties of PAC treated collagen hydrogel scaffold were evaluated by the measurement of setting time, surface roughness, and differential scanning calorimetry (DSC). The behavior of the hPDLCs in the collagen scaffold was evaluated by cell morphology observation and cell numbers counting. Results: The setting time of the collagen scaffold was shortened in the presence of PAC (p < 0.05). The surface roughness of the PAC-treated collagen was higher compared to the untreated control group (p < 0.05). The thermogram of the crosslinked collagen exhibited a higher endothermic peak compared to the uncrosslinked one. Cells in the PAC-treated collagen were observed to attach in closer proximity to one another with more cytoplasmic extensions compared to cells in the untreated control group. The number of cells cultured in the PAC-treated collagen scaffolds was significantly increased compared to the untreated control (p < 0.05). Conclusions: Our results showed that PAC enhanced the physical properties of the collagen scaffold. Furthermore, the proliferation of hPDLCs cultured in the collagen scaffold crosslinked with PAC was facilitated. Conclusively, the application of PAC to the collagen scaffold may be beneficial for engineering-based periodontal ligament regeneration in delayed replantation.

특발성 치근외흡수의 처치: 증례 보고

최유리나,김현하,박수정 대한구강악안면병리학회 2016 대한구강악안면병리학회지 Vol.40 No.5

External root resorption is one of the rare pathological condition of tooth. It is occurred when periodontal ligament or cementum on the root surface are either damaged or denuded. The causes and classifications have been variously described. Because of the various causes and patterns, and absence of sufficient and consistent evidence for treatment, proper diagnosis and treatment plan based on clinician’s experience and close communication with patient is important. This case report represents the rare case of external root resorption and the treatment. The tooth was retained functionally in oral cavity showing good healing state in 2-year follow-up.

Evaluation of irradiance and spectral output of visible light curing units used in the laboratory

최유리나,Su-Beom Choi,정지혜,장훈상 조선대학교 치의학연구원 2021 Oral Biology Research (Oral Biol Res) Vol.45 No.4

The irradiance of visible light curing units (LCUs) has been reported to decrease over time. However, the spectral output of used LCUs has rarely been evaluated. The purpose of this study was to evaluate the irradiance and the spectral output of visible LCUs used currently in laboratories. One halogen LCU (Optilux 360, O360), two polywave light emitting-diode (LED) LCUs (Bluephase Style [ST] and Bluephase G2 [G2]), and one single-peak LED LCU (Elipar S10, S10) were activated according to the manufacturers’ instructions. The irradiance and spectral output of the curing light were measured with a spectroradiometer in real time (n=10). Regarding the spectral peak and mean irradiance of the LCUs, O360 and G2 showed consistent data. However, ST showed spectral peaks at either 457 or 408 nm, and S10 at either 456 or 450 nm. The mean irradiance of ST and S10 was also inconsistent. Regarding the total energy, all LCUs surpassed the minimal energy value of 16 J/cm2 to fully polymerize an increment of 2 mm of composite resin. However, focusing on 420–540 nm range energy where camphorquinone is activated, some data showed an energy value for ST of less than 16 J/cm2, when the spectral peak was observed at 408 nm. Therefore, to evaluate the performance of the LCUs, not only the irradiance but also the spectral output should be monitored, especially in the case of polywave LED LCUs, where multiple spectral peaks are present.

Surgical treatment of mandibular first premolar with radicular groove: periradicular microsurgery

최유리나,Sue A Kim,Kkot Byeol Bae,Hoon-Sang Chang 조선대학교 치의학연구원 2024 Oral Biology Research (Oral Biol Res) Vol.48 No.1

This study aimed to report the results of a successful periradicular microsurgery on a mandibular first premolar with a radicular groove. A 38-year-old female reported a sinus tract on her buccal gingiva which was radiographically traced to the middle third of the mesial side of the root of her mandibular right first premolar (#44). A radicular groove and an accessory canal in the middle of the radicular groove were found using cone-beam computed tomography. After endodontic treatment, the sinus tract did not disappear; thus, periradicular microsurgery was performed. The radicular groove and the accessory canal were prepared and filled with fastsetting MTA without resectioning the root apex. After 3 weeks, the sinus tract disappeared, and complete healing was revealed on the periapical radiograph at a 5-month follow-up. Therefore, periradicular microsurgery is recommended in mandibular first premolars with radicular grooves on the accessible mesial side of the root.

Endodontic Treatment of Maxillary Third Molar with Two Separate Palatal Roots

최유리나 대한구강악안면병리학회 2016 대한구강악안면병리학회지 Vol.40 No.6

The presence of the microorganisms of untreated canals is one of the main reasons of the failure in the endodontic treatment. The knowledge of variations in the canal systems of the tooth is important for the successful endodontic treatment. In the maxillary molars, the presence of the two separate palatal roots is very rare variations. Although there have been several case reports of maxillary first and second molars, the case reports of maxillary third molars are very few. This case report presents the endodontic treatment of a maxillary third molar with two separate palatal roots. It is important to notice the clinical signs and analyze the radiographs carefully. The use of a microscope is helpful for the visualization of pulpal chamber, and pulpal chamber floor should be investigated thoroughly with endodontic explorer. The straight-line access for all the canal orifices is important for the success in the endodontic treatment.

Healing after horizontal root fractures: 3 cases with 2-year follow-up

최유리나,홍성옥,이석련,민경산,박수정 대한치과보존학회 2014 Restorative Dentistry & Endodontics Vol.39 No.2

Among dental traumas, horizontal root fractures are relatively uncommon injuries. Proper initial management and periodical evaluation is essential for the successful treatment of a root-fractured tooth. If pulpal necrosis develops, endodontic treatment is indicated, exclusively for the coronal fragment. Fragment diastases exert a great influence on healing at the fracture line and on pulpal necrosis. An adequately treated root-fractured tooth has a good prognosis. This case report describes the treatment and 2-yr follow up of 3 maxillary central incisors, first with horizontal root fracture, second with horizontal root fracture and avulsion, and third with horizontal root fracture and lateral luxation. All three cases were treated with mineral trioxide aggregate (ProRoot, Dentsply). During 2 yr of follow-up evaluation, the root-fractured teeth of the present patients were well retained in the arch, showing periodontal healing, even after endodontic treatment.

태권체조 참여자의 성취목표성향과 참여지속의도 및 추천의도의 관계

최유리,김일광 한국체육대학교 체육과학연구소 2022 스포츠사이언스 Vol.40 No.1

The purpose of this study is to investigate the relationship between achievement goal propensity, participation continuity intention, and recommendation intention for youth participating in Taekwondo gymnastics. To this end, adolescents aged 9 to 24 (Basic Act on Youth) were selected as a sample group, and a total of 313 questionnaires were collected. A total of 267 questionnaires were used for the final analysis, excluding 46 samples judged to have responded insincerely among the collected questionnaires. For data processing, frequency analysis, reliability analysis, exploratory factor analysis, confirmatory factor analysis, correlation analysis, and structural equation model analysis were performed using SPSS ver. 26.0 and AMOS ver. 22.0. Accordingly, the results of this study are as follows. First, among the achievement goal propensity, it was found that the self-goal propensity did not significantly affect the participation persistence intention, and the task goal propensity had a positive (+) effect on the participation persistence intention. Second, among the achievement goal propensity, it was found that the self-goal propensity had a negative (-) effect on the recommendation intention, and the task goal propensity had a positive (+) effect on the recommendation intention. Third, it was found that participation persistence intention had a positive effect on recommendation intention. Therefore, through the results of this study, Taekwondo gyms should develop Taekwondo gymnastics programs tailored to adolescents' psychological tendencies, establish more efficient marketing strategies, and improve overall participation and recommendation intentions.

IoT를 활용한 지능형 스마트 휠체어

최유리,고경은,박희주,이기영 한국인터넷방송통신학회 2022 한국인터넷방송통신학회 논문지 Vol.22 No.1

With the recent acceleration of an aging society, the use of wheelchairs is increasing, and wheelchair accidents are also increasing. However, despite this situation, the domestic wheelchair market is lacking in deveolpment of additional functions to prevent wheechair collisions and falls. Therefore, this paper aims to design and implement intelligent smart wheelchairs equipped with functions such as stair wheels and automatic illumination sensor headlights that allow wheelchairs to automatically avoid obstacles, notify interlocking applications when falls are detected. Accordingly, it is expected to increase the convenience of wheelchair users and prevent frequent wheelchair accidents. 최근 고령화 사회가 가속화되며 휠체어 사용이 늘고, 이에 따른 휠체어 사고 또한 증가하고 있다. 그러나 이러한상황 속에서도 국내 휠체어 시장은 휠체어의 충돌, 넘어짐 사고를 막을 추가적인 기능들의 개발이 미진한 상태이다. 그리하여 본 논문에서는 4차 산업혁명 시대에 발맞추어 휠체어가 장애물을 자동으로 피해가고, 넘어짐이 감지되면 연동 어플리케이션에 알림이 가며 어플리케이션에서 카메라 모니터링이 가능하고, 계단을 오를 수 있는 계단용 바퀴와 자동 조도감지 센서 전조등의 기능들이 탑재된 지능형 스마트 휠체어를 설계하고 구현하고자 한다. 이에 따라 점차 늘어나는 휠체어 사용자들의 편의를 증대시키고 빈번히 일어나는 휠체어 사고를 막을 수 있을 것으로 기대된다.