• The Journal of Advanced Prosthodontics
• /
• 제9권4호
• /
• pp.308-314
• /
• 2017

PURPOSE. The purpose of this study was to analyze the retention force changes and wear behaviours of double-crown systems over long-term use. MATERIALS AND METHODS. Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of $4^{\circ}$ and $6^{\circ}$. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS. In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the $LL-4^{\circ}$ group (32.89 N-32.65 N), and the lowest retention force values were found in the $ZA6^{\circ}$ group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION. More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.

• 대한소아치과학회지
• /
• 제47권2호
• /
• pp.219-227
• /
• 2020

치아 맹출은 치조골을 통해 치낭의 위치로부터 구강 내의 최종적인 교합 위치까지 치아가 이동해가는 복잡한 발육 과정이다. 치아의 맹출 장애는 맹출 일련의 단계 중 어느 단계에서도 일어날 수 있으며, 하악 제2유구치의 일차성 만기잔존과 하악 제1대구치의 수평 매복이 동시에 발생한 증례는 매우 드물다. 이번 연구의 목적은 제2유구치의 일차성 만기잔존이 동반된 하악 제1대구치의 수평매복의 두 증례에 대한 치료를 제시하는 것이다. 일차성 만기잔존으로 맹출 지연된 하악 제2유구치는 발치하였고, 수평매복된 하악 제1대구치는 교정적 견인을 시행하였다. 이후 계승 소구치의 맹출 공간을 위해 공간획득을 도모하였고 계승 소구치의 변위가 개선되었으며 제1대구치는 정상적인 맹출이 유도되었다.

• 대한소아치과학회지
• /
• 제40권4호
• /
• pp.314-320
• /
• 2013

하악 제1대구치 맹출장애의 빈도는 전체 인구의 0.01%로 드물게 나타나며, 발생 원인과 발견 연령 등에 따라 매복, 일차적 만기잔존(primary retention), 이차적 만기잔존(secondary retention) 등으로 분류된다. 치료로는 주기적 관찰, 외과적 노출술, 외과적 노출술 후 교정적 견인술, 탈구를 동반한 교정적 견인술, 외과적 재위치술, 발치 등의 방법을 적용할 수 있다. 이 증례보고는 각각 매복, 일차적 만기잔존, 그리고 이차적 만기잔존으로 진단된 5명의 환자들에서 다양한 치료방법을 이용하여 하악 제1대구치를 성공적으로 교합유도한 증례들을 보여준다. 맹출장애를 갖는 하악 제1대구치는 치아의 평균적인 맹출시기에 임상 및 방사선검사를 통해 매복, 일차적 만기잔존, 그리고 이차적 만기잔존으로 적절하게 진단내려질 수 있으며, 치아의 맹출 정도, 대합치와 인접치와의 관계, 환자의 연령, 협조도, 경제적 상황을 종합적으로 고려하여 치료되어야 한다.

• 펄프종이기술
• /
• 제40권5호
• /
• pp.1-10
• /
• 2008

Synthetic mineral microparticles (SMM) is a patented system which has been developed to promote drainage of water and retention of fine particles during papermaking. It is shown in patents that the SMM system can have advantages in both of drainage and retention, compared with montmorillonite (bentonite), which is one of the most popular materials presently used in this kind of application. Turbidity and gravity drainage time were measured using a Britt-Jar test with representative SMM formulations, in order to confirm the efficacy of SMM covering a wide range of compositions and discover effects of some key variables that have the potential to lead to unexpected advantages in terms of the effectiveness of the microparticles, when used in combination with a cationic polyacrylamide treatment of papermaking furnish. An iron silicate showed highest retention performance, as well as suitably fast drainage time relative to other metal silicate and bentonite. Zinc silicate improved retention and drainage. SMM synthesized from aluminum sulfate ($Al_2(SO_4){_3}$) did not show a benefit in retention and drainage, relative to bentonite. SMM synthesized from aluminum chloride ($AlCl_3$) performed better in drainage and retention than bentonite when the Al/Si ratios were 0.76 and 1.00. It was found that when the Al/Si ratio and neutralization are considered, pH variation due to the change of Al/Si ratio can be a key factor to control the size of primary metal silicate particles and the degree of coagulation of the primary particles.

• 대한치과교정학회지
• /
• 제35권3호
• /
• pp.227-237
• /
• 2005

하악 제1대구치의 맹출 장애는 매우 드문 편으로 맹출로에 물리적인 장애가 있거나 맹출 과정의 결함으로 인해 생긴다. 하악 제1대구치의 맹출 장애가 있으면 그 원인을 살펴 정확한 치료계획을 세워야 하는데 무엇보다도 조기진단과 조기 치료가 중요하다 일차미맹출(primary retention)된 하악 제1대구치를 치개 절개와 forced eruption을 통해 치료하여 치료결과가 양호하고 성공적으로 유지된 증례를 살펴보고자 한다.

• 근관절건강학회지
• /
• 제30권2호
• /
• pp.103-110
• /
• 2023

Purpose: The present study examined the psycho-emotional factors that affect the retention intention among advanced beginner-stage nurses. Methods: A cross-sectional study was conducted using a convenience sample of 118 nurses with a work experience of at least one to three years of work experience in a university hospital in Suwon, Korea. Structured questionnaires were used to assess retention intention, emotional labor, and resilience. Multiple regression analysis was used to examine factors affecting retention intention. Results: Retention intention had a moderate mean score (4.75 out of 8). Factors influencing participants' retention intention were founded in the order of resilience (β=.29, p<.001) and emotional labor (β=-.20, p=.011) after adjusting nursing satisfaction as a covariate. The multiple regression model accounted for 42% of the variance in retention intention (p<.001). Conclusion: Resilience and emotional labor may be primary factors influencing retention intention of advanced beginner-stage nurses. Therefore, this study finding suggested that psycho-emotional factors such as emotional labor and resilience should be considered while designing programs to increase nurses' retention intention.

• 대한치매학회지
• /
• 제17권3호
• /
• pp.110-119
• /
• 2018

Background and Purpose: To analyze $^{18}F-THK5351$ positron emission tomography (PET) scans of patients with clinically diagnosed nonfluent/agrammatic variant primary progressive aphasia (navPPA). Methods: Thirty-one participants, including those with Alzheimer's disease (AD, n=13), navPPA (n=3), and those with normal control (NC, n=15) who completed 3 Tesla magnetic resonance imaging, $^{18}F-THK5351$ PET scans, and detailed neuropsychological tests, were included. Voxel-based and region of interest (ROI)-based analyses were performed to evaluate retention of $^{18}F-THK5351$ in navPPA patients. Results: In ROI-based analysis, patients with navPPA had higher levels of THK retention in the Broca's area, bilateral inferior frontal lobes, bilateral precentral gyri, and bilateral basal ganglia. Patients with navPPA showed higher levels of THK retention in bilateral frontal lobes (mainly left side) compared than NC in voxel-wise analysis. Conclusions: In our study, THK retention in navPPA patients was mainly distributed at the frontal region which was well correlated with functional-radiological distribution of navPPA. Our results suggest that tau PET imaging could be a supportive tool for diagnosis of navPPA in combination with a clinical history.

• 대한소아치과학회지
• /
• 제24권4호
• /
• pp.781-787
• /
• 1997

In spite of the improvements of the techniques in the field of preventive dentistry, many children still present with extensive destruction of primary anterior teeth. Not only the practioner must consider the pulp state of the primary incisor, but also restore the form, function and esthetics of the tooth. Restorative treatment of primary incisor tooth requires durability, retention and esthetics. Stainless steel crowns used in restoring primary anterior teeth is retentive and durable in comparison with the composite resin, celluloid crown. But they are not esthetic. To enhance the esthetics of the anterior stainless steel crown without reducing its superior retention, an open-face stainless steel crown has been suggested. Several authors have suggested cutting away the labial portion of the stainless steel crown and placing the composite resin in that area. By following this technique, the practioner can prepare a retentive, durable, and esthetic restoration for primary teeth which have suffered from extensive loss of teeth structure. In addition, the single missing primary anterior teeth can be successfully restored by soldering the stainless steel crown together. Open-face stainless steel crown is indicated in the areas of large interproximal lesions involving incisal edge, crown fracture with pulp exposure and congenital malformation of the teeth. By this technique, the practioner can restore primary anterior teeth successfully regardless of the amount of remaining tooth structure, bruxism habit and presence of attrition. In this case, rampant caries with extensive loss of tooth structure and single missing of primary anterior tooth hart been successfully treated with open-face stainless steel crown.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
• /
• pp.61-66
• /
• 2006

Over the past 20 years there has been a revolution involving the use of nano or macro size particles as drainage and retention systems during the manufacture of paper. More recently a group of patented technologies called Synthetic Mineral Microparticles (SMM) has been invented and developed. This system has potential to further promote the drainage of water and retention of fine particles during papermaking. Prior research, as well as our on preliminary research showed that the SMM system has advantages in both of drainage and retention compared with montmorillonite (bentonite), which one of the most popular materials presently used in this kind of application. In spite of the demonstrated advantages of this SMM system, the properties and activity of SMM particles in the aqueous state have not been elucidated yet. Streaming current titrations with highly charged polyelectrolytes were used to measure the charge properties of SMM and to understand the interactions among SMM particles, fibers, fiber fines, and cationic polyacrylamide (cPAM) as a retention aid. It was found that pH profoundly affects the charge properties of SMM, due to the influence of Al-ions and the Si-containing particle surface. SEM pictures, characterizing the morphology, geometry and size distribution of SMM, showed an broad distribution of primary particle size. Dilution of SMM mixturee appeared to wash out particles smaller than 100 nm from the surface of larger particles, which themselves appeared to be composed of fused primary particles. DSC thermoporometry was used to measure the size distribution of nanopores within SMM particles.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권7호
• /
• pp.255-264
• /
• 2021

The purpose of this study is to analyze the role of customer value and customer trust as a mediator of flexibility influence on customer retention. The study applies SEM tools with WarpPLS analysis and translates customer value and customer trust as mediation. This study was organized into three parts: exploratory research, descriptive research, and explanatory research. The quantitative approach in this study uses a survey method by taking samples from the population. This is a latent variable that is measured using a research instrument in the form of a questionnaire. The survey was conducted by distributing questionnaires to respondents. This research was conducted at PT. Nusa Prima Logistics Terminal Teluk Lamong by taking primary data, in the form of assessments or perceptions from respondents, so a survey was conducted by submitting a questionnaire directly to 194 respondents. Quantitative data analysis was performed using Structural Equation Modeling (SEM) to answer the research hypothesis. Flexibility is very influential in increasing customer retention so to develop customer retention, it is necessary to increase flexibility, customer value, and customer trust. The novelty in this research lies in identifying the role and position of customer value and customer trust as mediation that affect customer retention.