• Journal of the korean academy of Pediatric Dentistry
• /
• v.24 no.3
• /
• pp.651-659
• /
• 1997

This report presents a case of adolescent patient who had multiple impacted teeth and no systemic disease, and was treated with removable and fixed orthodontic appliances. The results obtained through these cases were summarized as follows : 1. Even in the case without systemic disease, there can be the delayed eruption of multiple teeth 2. If the root formation is not completed, root have no excessive curvature, axial inclination of the tooth is not excessive, and there is eruption space, the tooth can be induced to normal occlusion. 3. Since esthetically proper occlusion and dentition was acquired by recovery of the impacted teeth to normal occlusion, the prosthodontic treatment after extraction of the impacted teeth was less needed. 4. This treatment brought psychological stability to pubertal patient who was interested in his facial profile.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.3
• /
• pp.82-88
• /
• 2003

The nondestructive internal quality evaluation of agricultural products has been strongly required from the needs for individual inspection. Recently, the ultrasonic wave has been considered as a solution fur this problem, and an ultrasonic system was constructed for the ultrasonic NDE of fruits and vegetables in our previous work. In this paper, the practical applicability of our ultrasonic system is tested fur the inspection of internal defects (central cavity) in Atlantic potato. Sound speed and RMS of transmitted ultrasonic wave signal were measured and classification algorithm using 2 dimensional stochastic analysis. was presented. Experimental results showed greater value of sound speed and RMS (root mean square) of transmitted signal in normal samples than in abnormal samples with cavity. Also a stochastic method to distinguish normal and abnormal showed fault detection rate less than 5%.

• The Plant Pathology Journal
• /
• v.24 no.3
• /
• pp.352-356
• /
• 2008

Root discs of 4-year-old ginseng, Panax ginseng C. A. Meyer, were inoculated with the higher($10^8$ colonyforming units(CFU)/ml) and lower($10^6\;or\;10^5$ CFU/ml) initial inoculum levels of a plant-growth promoting rhizobacterium(PGPR), Paenibacillus polymyxa GBR-1 to examine rot symptom development and bacterial population changes on the root discs. At the higher inoculum level, brown rot symptoms developed and expanded on the whole root discs in which the bacterial population increased continuously up to 4 days after inoculation. In light and electron microscopy, ginseng root cells on the inoculation sites were extensively decayed, which were characterized by dissolved cell walls and destructed cytoplasmic contents. However, no rot symptoms were developed and the bacterial population increased only during the initial two days of inoculation at the lower inoculum level($10^6$ CFU/ml) of P. polymyxa GBR-1. At the lower inoculum level($10^5$ CFU/ml), boundary layers with parallel periclinal cell divisions, structurally similar to wound periderm, were formed internal to the inoculation sites, beneath which the cells were intact containing numerous normal-looking starch granules and no disorganized cell organelles, suggesting that these structural features may be related to the suppression of symptom development, a histological defense mechanism.

• Restorative Dentistry and Endodontics
• /
• v.37 no.1
• /
• pp.50-53
• /
• 2012

Cone-beam computed tomography (CBCT) is a useful diagnostic tool for identification of both internal and external root configurations. This case report describes the endodontic management of a lateral incisor with both dens invaginatus and external root irregularity by using CBCT. Nonsurgical endodontic retreatment was performed on the lateral incisor with dens invaginatus. A perforation through the dens invaginatus and external concavity was repaired using mineral trioxide aggregate. After 18 mon of follow-up, there were no clinical symptoms. Recall radiographs appeared normal and showed healing of the periapical pathosis. The understanding of both internal root canal configuration and external root irregularity using CBCT can ensure predictable and successful results.

• Journal of the Korean Mathematical Society
• /
• v.59 no.4
• /
• pp.717-731
• /
• 2022

We introduce the notion of quasi-roots and study their uniqueness in right-angled Artin groups.

• Bulletin of the Korean Mathematical Society
• /
• v.42 no.3
• /
• pp.571-577
• /
• 2005

In this paper we prove that if T is a k-th root of a p­hyponormal operator when T is compact or T$^{n}$ is normal for some integer n > k, then T is (generalized) scalar, and that if T is a k-th root of a semi-hyponormal operator and have the property $\sigma$(T) is contained in an angle < 2$\pi$/k with vertex in the origin, then T is subscalar.

• Journal of Plant Biotechnology
• /
• v.36 no.2
• /
• pp.170-173
• /
• 2009

Leaf and petiole explants of Pulsatilla koreana NAKAI were cultured on MS medium supplemented with various concentrations of zeatin, kinetin or BAP combined with 0.05 mg/L IAA. After 6 weeks of culture, effects of cytokinin on adventitious shoot formation from explants were investigated. The highest frequency of shoot formation was obtained when petiole explants were cultured on medium with 0.5 mg/L zeatin and 0.05 mg/L IAA. Regenerated shoot were transferred on to root induction medium. The best root formation was observed at 1/2 MS medium with 1.5 mg/L NAA. Rooted plantlets were transplanted to a mixture of perlit and soil (1:3), where they were successfully acclimatized.

• Proceedings of the KACD Conference
• /
• 2002.11a
• /
• pp.720-720
• /
• 2002

A number of investigations have shown that the presence of bacteria is prerequisite for developing pulpal and/or periradicular pathosis. Depending on the stage of pulpal pathosis, various species of bacteria can be cultured from infected root canals. Kakehashi et al. showed that exposure of pulpal tissue in germ-free rats was characterized by minimal inflammation and dentinal bridging while exposure of pulpal tissue in conventional rats with normal oral flora was characterized by pulpal necrosis, chronic inflammation, and periapical lesions. Currently used methods of cleaning and shaping, especially rotary instrumentation techniques, produce a smear layer that covers root canal walls and the openings to the dentinal tubules. The smear layer contains inorganic and organic substances that include fragments of odontoblastic processes, microorganisms, their by products and necrotic materials. Because of its potential contamination and adverse effect on the outcome of root canal therapy, it seems reasonable to suggest removal of the smear layer for disinfection of the entire root canal system. Presence of this smear layer prevents penetration of intracanal medications into the irregularities of the root canal system and the dentinal tubules and also prevents complete adaptation of obturation materials to the prepared root canal surfaces. Removal of the smear layer by an intracanal irrigant and placement of an antibacterial agent in direct contact with the content of dentinal tubules should allow disinfection of this complex system and better outcome for the root canal therapy. A new solution, which was a mixture of a tetracycline, an acid, and a detergent(MTAD), was developed in the Department of Endodontics, Dental School. Lorna Linda University, USA. It has been demonstrated that MTAD was an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when used as a final irrigant in conjunction with 1 % NaOCl as a root canal irrigant. Studies are in progress to compare the anti- microbial properties of this newly developed solution with those of sodium hypochlorite and EDTA that are currently used to irrigate the root canals and remove the smear layer from the surfaces of instrumented root canals.canals.

• The korean journal of orthodontics
• /
• v.21 no.3
• /
• pp.635-656
• /
• 1991

It was the aim of this investigation to evaluate some histologic aspect of rat pulp tissue after it had been compromised by an experimental orthodontic force. Experimental animals of thirty five Spraque-Dawley rats were employed. The first upper molars had been successively mesial moved (initial load 100 gr.) with a closed coil spring during 21 days. The experimental periods were set on immediate, 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks following retention time. On each experimental period, the rats were killed and prepared for the light microscopy. After prepared with H/E stain and Gomori's one-step trichrome stain, the specimens were analyzed with evaluation criteria which were adopted in this study. The result may be summarized as follows; 1. The main pulp changes due to experimental orthodontic force included vacuolization of odontoblastic layer, circulation disturbance, root resorption, reduced pulp collagenous fiber density and mean cell count of pulp fibroblast in the immediate group. 2. The pulp tissue changes were revealed reversible because the relieved pulp tissues from experimental orthodontic force were recovered rapidly in each evaluation criteria during retention periods. 3. Compared with normal control group, pulp collagenous fiber density were decreased in immediated group (p < 0.01), but increased in each retention groups. These seem to suggest that the pulp tissues were aged after experimental orthodontic force conditions. 4. Compared with normal control group, mean cell counts of pulp fibroblasts were decreased in immediate group (p < 0.05), but increased continuous in each retention groups. These seem to indicate that the pulp tissues were highly regenerative after experimental orthodontic force conditions. 5. Compared with normal control group, root resorptions occurred in all immediate specimens (p < 0.01) and they were healed in each retention periods, but often observed in 4 weeks retention group. These seem to indicate that root resorptions were recovered slowly after experimental orthodontic force conditions.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.3
• /
• pp.409-415
• /
• 2005

Impaction of permanent incisor occurs rare than the canine & third molar. But it's often observed in school age child. The causes of impaction are trauma, space deficiency, mesiodens, infections of root apex, etc. In spite of elimination of cause, normal eruption of impacted tooth is rare. Though eruption is normal, the position of tooth will be incorrect. Because the impacted tooth results in malocclusion, root resorption of adjacent tooth, pathologic cystic change, it should be confirmed the precise position by clinical and radiographic exam and found the correct location by appropriate treatment plan. In case of pathologic change of impacted tooth and injury to adjacent tooth, it will be extracted. But through orthodontic retraction, the function and esthetics of tooth can be restored. It is important that impacted tooth should be detected early and diagnosed correctly, and appropriate treatment plan should be made. Before impacted tooth is retracted, the considerations of space for alignment and anchorage should be preceded and through appropriate force and mechanics, the side effects, for example, a root resorption should be minimized. In this study, we guided impacted tooth to normal position by using a forced eruption.