• 펄프종이기술
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• 제29권2호
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• pp.46-50
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• 1997

• 대한치과의사협회지
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• 제57권7호
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• pp.403-411
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• 2019

A cracked tooth is defined as an incomplete fracture initiated from the crown and extending subgingivally and usually directed mesiodistally. Cracked teeth were most frequently involved in mandibular and maxillary molars at the age of 50s. Cracks occurred mainly in nonbonded restorations such as gold and amalgam, and majority of cracks were found in intact teeth. A pulpal and periapical diagnosis is dependent on the extent of the crack and duration of the symptom. The pulp of a cracked tooth might become inflamed because of microleakage, which induces thermal sensitivity. Once the crack has extended and exposed the pulp, severe pulp and periapical pathosis will likely be present. In addition, the extended crack can cause a bony dehiscence with a resulting narrow and deep periodontal pocket. Therefore, early diagnosis of the cracked tooth and proper treatment planning are important for clinician.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2004년도 제30회 국제세미나
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• pp.1-17
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• 2004

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 추계학술발표회 논문집
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• pp.217-229
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• 2011

• Restorative Dentistry and Endodontics
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• 제37권4호
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• pp.240-244
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• 2012

Crown reattachment is the most conservative treatment which can be used to restore fractured tooth, presumably with sufficient strength, while maintaining original contour, incisal translucency, and reducing chair time and cost. However, in case of crown fracture with pin-point pulp exposure, we should cautiously minimize the irritation to the pulp and consider pre-treatment pulpal status, choice of pulp capping materials, choice of bonding system and treatment sequence during crown reattachment procedures. This case reports the considerations while crown reattachment with direct pulp capping using calcium hydroxide (Dycal, Dentsply Caulk).

• Journal of the Korean Wood Science and Technology
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• 제8권3호
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• pp.64-76
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• 1980

Fig. 8 summarizes the present status of high yield pulp production and the directions of research on modification. A thick line indicates pulping process presently in use. As mentioned previously, one kind of modification is to introduce hydrophilic groups onto the pulp. Still unsolved is whether or not the introduction of hydrophilic groups should be restricted to lignin only. Goring (28) reported that middle lamella lignin has fewer phenolic hydroxyl groups than cell wall lignin and suggested that such a difference in the lignin may be useful in the removal of middle lamella lignin. The introduction of hydrophilic groups onto pulp may not be enough to modify high yield pulp. The removal of some portion of carbohydrate may be also necessary from the standpoint of softening of pulp fibers. There is no information at what lignin and carbohydrate, and how much should be removed. The combination with synthetic high polymers may also be important in modifying high yield pulp. Prof. C. Schuerch of the State University of New York who was a visiting professor at the University of Tokyo in 1974, mentioned that the hydrophilicity of lignin would be promoted, if phenolic hydroxyl or carboxyl groups could be introduced into the aromatic nucleus of lignin. If this were possible. this process would also mean a pulp yield of more than 100%. This idea is just one example of the expectation made possible through lignin chemistry. Instead of the introduction of hydrophilic group, the oxidative degradation of aromatic nucleus of lignin may also be useful in promoting the hydrophilicity of pulp. In this case, ozone may be an excellent chemical. However, there are a lot of problems to be solved such as homogeneity of reaction and selectivity of ozone for lignin. The above ideas are summarized in Fig. 9. There are many problems to be solved in the production of an excellent high yield pulp which is comparable to chemical pulp. The information from wood chemistry hopefully will elucidate some of the problems mentioned above.

• 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.

• Journal of Biosystems Engineering
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• 제30권5호
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• pp.285-292
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• 2005

Extrusion process and physical properties of extrudates of pulp powder (TMP, thermomechanical pulp fibers) mixed with expanding additives was evaluated to develop biodegradable packaging materials. To find out the optimum condition, the status of extrusion process, coefficient of elastic and expansion ratio of extrudates were tested on the composites (wheat flour, soluble starch, polyvinyl alcohol), blending conditions of composites and moisture contents of extrudates. In case of material composition, wheat flour played a key role to keep extrusion process irrespective of the added amounts of soluble starch and polyvinyl alcohol. The coefficient of elastic of extrudates was increased and the expansion ratio was reduced as the added amounts of wheat flour increased. Also, the coefficient of elastic of extrudates was decreased as the moisture content of extrudates increased. The lowest coefficient of elastic was 439.55 kPa under the condition, of pulp powder mixed with $20\%$ of wheat flour based on pulp weight and $10\%$ of soluble starch based on wheat flour weight and controlled $20\%$(wb) of moisture content.

• 펄프종이기술
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• 제40권4호
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• pp.51-58
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• 2008

This paper presents the effect of acid treatment on the removal of metals and the brightness of pulp. The bleached kraft pulps, metal-absorbed pulps and recycled pulps((ONP, OCC, MOW, and SC) were treated with the acidic solutions. Among metals in the bleached kraft pulps, Cu, Ca and Mg were removed easily by the acid washing, whereas Fe, Al and Si were not removed. The acid washing also removed distinctly metals from the metal-absorbed pulps. The metals absorbed in pulps reduced the brightness (%, ISO). Especially, Fe was the most detrimental metal. However, the brightness which was decreased by metals was restored to the status quo by the acid washing. The level of metals in recycled pulps was gradually reduced after the first flotation and acid treatment. Hence, the degree of metal removal by the acid washing was mainly dependent upon the kinds of waste pulps and metal ions.

• 펄프종이기술
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• 제32권1호
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• pp.94-100
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• 2000

This study was carried out to understand the present status of the quality evaluation capability of domestic fine paper industry. Six light weight coated papers and one wood containing printing and writing paper with similar basis weights were produced by seven paper companies and their properties were evaluated at four different testing laboratories of domestic fine paper mills. Paper properties including basis weight , thickness , tensile, tear , brightness , opacity, etc were examined , and the repeat ability and reproducibility of the test results were analyzed. Results showed that repeatability of the measurements within the laboratory was satisfactory . Reproducibility of the measurements between laboratories, however, was not satisfactory. This showed that strict implementation of the standard testing methods and periodic calibration of testing equipments should be made to improve quality evaluation capability of domestic fine paper industry.