• 펄프종이기술
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• 제43권3호
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• pp.128-136
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• 2011

In order to investigate the relationship between the prices of wood chips and pulps, regression analysis and cointegration test were conducted. Test results indicated that pulp producers adjusted pulp price in response to the change in wood-chip price and there were a long-run relationship between these prices. This implied that by raising the selling price of pulp, pulp producers avoid profit loss incurred by the increase in the wood-chip price. The existence of cointegration between wood chips and pulp prices implied that pulp producers were competing when they set the selling price of pulp.

• 펄프종이기술
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• 제37권4호통권112호
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• pp.8-17
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• 2005

WCT (Wet compaction test) is a new fiber evaluation method developed recently by Seo and its test results can be used as a predictor for pulp quality and its paper property Bleached chemical pulps (SwBKP, HwBKP), recycled pulp (OCC), and mechanical pulp (BCTMP) were used for the furnishes to be tested by WCT We compared the WCT results to conventional fiber evaluation tests such as WRV (Water Retention Value), free ness, and fiber length in this study, and found that WCT always gave better regression coefficients in relation to pulp quality (drainage), and paper properties (density, tensile, tear, and burst strength). WCT may be used on-line in papermachine.

• 전자공학회논문지SC
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• 제41권6호
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• pp.43-49
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• 2004

치수 검사(pulp test)는 치아에 물리적 및 화학적 자극을 가하여 치수의 생활력(vitality) 여부를 판별하는 검사이다. 치과 임상에서 수행되는 검사 과정에서 피검자는 치아에 가해지는 역치 이상의 자극으로 인하여 큰 고통과 스트레스에 노출된다. 본 논문에서는 생활치수의 전기 치수 검사 시, 자극의 강도를 서서히 증가시켜 역치에 이르게 되면 나타나는 피검자의 동통반응으로 개구반사에 의한 악이복근의 근전도, 발성에 의한 음성 반응, 손가락의 움직임에 의한 반응을 각각 측정하였다. 또한 동통 반응이 발생하는 시점으로부터 자극이 차단될 때까지 피검자에게 필요이상으로 인가되는 과용 자극 시간을 측정하였으며, 과용자극 시간 측정 시 치수 검사기의 자극 차단 주체자에 따른 과용 자극 시간을 측정 분석하였다. 이러한 결과를 바탕으로 동통 반응에 의한 인체 반응 신호를 이용하여 치수검사기의 출력을 자동으로 차단하는 제어 스위치를 구성하였다. 피검자가 역치 자극을 느낀 후 나타나는 최초의 인체 반응의 10 ms 이내에 신속하게 검사기의 출력을 차단함으로써 과용자극 시간을 줄이고자 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.727-730
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• 2003

Electric pulp test is a method to examine the vitality of dental pulp using the electrical stimulation. During the pulp test, the current stimulates intradental nerve, and makes patients painful. Some studies were accomplished to measure the responses of subjects by stimulating over the sensory threshold. In this study, we examined the time delay between pain feeling and stimulation stop in clinical situation. And we measured the activated responses(EMG in anterior belly of digastric muscle, voice, and finger span). As a result, it was verified that the minimum and maximum delay was EMG and voice, respectively. By reducing the excessive stimulus time, the unnecessary pain can be minimized using EMG that has the minimum delay.

• 대한소아치과학회지
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• 제26권2호
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• pp.310-316
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• 1999

외상받은 치아에서 치수강폐쇄, 치수괴사, 치근흡수, 인접치조골소실, 치근단염증성변화 및 치아상실 등의 부작용이 나타날 수 있으며, 이는 치근형성정도, 탈구의 종류, 고정의 기간에 따라 예후가 달라진다. 외상후 부작용의 빈도를 줄이기 위해서는 조기에 치수생활력 유무를 판단하는 것이 중요하다. 그러나 미성숙치근을 가진 치아는 치수내 신경발달분포가 불완전하고, 환자의 연령이 어려 술식에 대한 이해력이 부족하고 치과에 대한 공포감 때문에 전기치수검사등의 전통적인 치수생활력 방법의 신뢰도가 떨어진다. 반면 laser Doppler flowmetry는 치수혈류량을 측정하여 치수생활력을 검사하는 방법으로서 보존적이며 객관적이고, 외상후 비교적 조기에 치수생활력을 측정할 수 있는 신뢰도가 높은 치수생활력 검사방법이다. 이에 저자는 외상받은 미성숙치아를 대상으로 냉검사, 전기치수검사, laser Doppler flowmetry를 이용하여 치수생활력을 검사하여 다음과 같은 결과를 얻었다. 1. 외상받은 치아의 치수생활력은 초기에는 음성으로 나타날 수 있으나 시간의 경과에 따라 양성으로 회복될 수 있어 장기간의 관찰이 필요하다. 2. 치수생활력은 냉검사, 전기치수검사 보다 laser Doppler flowmetry 에서 더 빨리 나타났다. 3. 냉검사와 전기치수검사의 두가지 치수생활력 검사방법중 전기치수검사 보다 냉검사가 신뢰도가 더 높았다.

• 대한소아치과학회지
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• 제25권3호
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• pp.562-568
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• 1998

저자는 본 병원에 내원한 환자중 미완성치근단을 가지고 있으며 외상받은 치아 및 자가이식치아를 대상으로 기존의 치수생활력 검사방법과 더불어 LDF를 이용한 검사방법을 통해 다음과 같이 요약할 수 있다. 1. 치수생활력유무를 판단함에 있어 현재까지 널리 사용된 전기치수검사, 냉검사등의 방법은 치수 내 신경발달 정도 및 피검자의 주관에 의해 반응이 다르게 나타나는 경우가 많다. 2. 이에 반해 LDF를 이용한 치수생활력 검사방법은 위음성 및 위양성 반응의 빈도가 낮아 신뢰도가 높으며 비교적 조기에 치수생활력을 측정할 수 있는 우수한 방법이다.

• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.95-102
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• 1999

The purpose of this study was to observe histopathologically the influence of advanced periodontitis on pulp tissue, and to conclude the correlation between the results with clinical manifestations. The samples were teeth with over 7mm pocket depth and over 50% radiographic bone loss. These were diagnosed to have very poor prognosis and thus planned to be extracted. Those with any of following conditions were excluded from the samples, loss of vitality, periapical pathology, restoration or prosthesis, dental caries, and attrition or abrasion. It was because these conditions could affect pulp without any correlation with periodontal disease. For the experiment, 17 teeth from 11 patients were selected. Average age of patient was 47. Each tooth was examined for following categoris; pocket depth, gingival recession, electric pulp test, mobility, percussion test, sensitivity test. The extracted teeth were fixed buffered neutral formalin solution. It was decalcified using 4% nitric acid. Sliced histological samples observed using light microscope, for pulp status, and severeity of inflammation. 4 samples were excluded due to histologic sample discrepency. Thus 13 samples were subject to observation. 4 showed normal conditions. Focal reversable pulpitis was shown in 5 samples. Chronic pulpitis was observed 1 sample. Pulpal abscess was observed in 3 samples.

• 펄프종이기술
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• 제40권2호
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• pp.29-36
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• 2008

In order to give pulp surfaces anti-bacterial functionality and photo-catalytic deodorant ability, functional pulps was made using a surface modification method with Ag nano-colloidal solution and $TiO_2$ filler. Hygiene paper was made with the specially modified pulp, and anti-bacterial and deodorant tests were carried out. The Ag nano-colloidal solution was coated on the surface of the pulp using the high pressurized gas phase squirt through the spray nozzle mounted on the hybridization system. The surface modified functional pulp was hybridized with the optimum ratio of $TiO_2$(fine particle) to pulp(core particle) under the condition of $6,000{\sim}10,000$ rpm for $3{\sim}7$ minutes in the system. The anti-bacterial functionality of the hygiene paper was confirmed by the halo test in which the formation of the clear zone around the hygiene paper sample was observed. The inhibition growth test using MIC bioscreen C showed the inhibition growth effect of the bacteria as the reaction time was increased. The photo-catalytic effect measurement of the $TiO_2$ for 4 hours of the reaction showed $50{\sim}60%$ of decomposition rate, reaching over 60% for 5 hours of the reaction.

• Restorative Dentistry and Endodontics
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• 제46권3호
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• pp.34.1-34.9
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• 2021

Objectives: This study aimed to assess the presence of pulp stones through an examination of cone beam computed tomography images and correlate their prevalence with age, sex, dental arch and side, tooth type, and restoration type and depth. Materials and Methods: Cone beam computed tomography images obtained from 673 patients and archival data on 11,494 teeth were evaluated. The associations of pulp stones with age, sex, dental arch and side, tooth type, and restoration type and depth were noted. All the measurements were subjected to a χ² test and one sample χ² test (p < 0.05). Results: In the study group, 163 (24.2%) patients and 379 (3.3%) teeth had at least one pulp stone. The pulp stone frequency in those aged 30-39 years was significantly greater than in those aged 18-29 and ≥ 60 years, and the frequency was higher in females than in males (p < 0.05). The highest prevalence of pulp stones was found in maxillary dental arches and molar teeth (p < 0.05). Pulp stones were significantly more common in medium-depth restorations (p < 0.05). Conclusions: Maxillary molar teeth, medium-depth restorations, individuals aged 30-39 years and females had a greater percentage of pulp stones.

• 펄프종이기술
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• 제33권2호
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• pp.24-31
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• 2001

As a novel method to improve strength properties of recycled test liner, Condebelt press drying system was introduced and adopted into Korea. New press drying treatment could enhance the surface and strength properties in accordance with the increase of sheet density. However, Condebelt drying can not increase the density of repeatedly recycled test liner as much as that of virgin UKP and at the same density condition, the strength of Condebelt press dried UKP is greater than that of press dried test liner. In order to increase the strength of test liner, two attempts were tried in this study. First, addition of polyelectrolytes, dry strength agent was investigated with a view to promote the fiber bonding potential of reclaimed corrugated container pulp. Second, blending effect of fines were analyzed in an aims of increasing density and strength of test liner. The results were as follows; Even in the case of test liner densified by Condebelt press dryer, addition of amphoteric PAM as a dry strength agent was effective in increasing strength properties and so the effect of dry strength agent on improving bonding potential of recycled OCC fiber could be confirmed. As an appropriate addition level of amphoteric PAM, below 1% based on dry pulp weight was suggested. Different from virgin UKP, density of recycled test liner can be increased by the blending of OCC fines and strength properties also can be improved. However, excessive blending of OCC fines could result in decreasing of density and serious weakening of test liner. The best blending ration of fines in test liner can be determined as about 30%. Taking into account the fines content in general OCC pulp as 50%, excessive 20% of fines were supposed to be fractionated and removed in order to achieve the best strength of Condebelt press dried test liner.