• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.4
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• pp.492-498
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• 2018

This study was conducted to investigate the characteristics of subculture times in the early, middle, and late passages by measuring the time under subculture until it was judged that the supernumerary tooth-derived pulp stem cells (sDPSCS) were no longer proliferating. Three supernumerary teeth from two healthy six-years old boys were extracted and stem cells were obtained from the pulp tissue. This was called SNT1 (supernumerary tooth 1), SNT2, and the supernumerary tooth from another child was named SNT3. SNT1 and 2 were subcultured at the same time and SNT3 was subcultured a little faster. The mean time of complete subculture was $3.6{\pm}1.1$ days. Total passages were cultured up to $23.3{\pm}0.6$ and took 83 days. These were divided into three groups based on the passage. The increase rate of time taken in subculture between group I and group II was 11.9%, but the rate between group II and group III was 28.6%, which was 2.4 times increased. The time taken between passages during long-term subculture up to 22 passages shows a regressive pattern y = 0.1169x + 2.25 and y = 0.1169x + 2.0. In conclusion, the passage time of SPSCs increased in late passages, and it shows a similar pattern.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.7-16
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• 1980

The author observed the periodontal tissue reactions to the root canal sealers after root perforations were made intentionally in dogs. The perforations were made on 74 teeth from 7 dogs. The experiments were performed in two different modes of procedure: In Group I, the perforations were made through the root canal to the alveolar bone. In Group II, the perforations were made from site of alveolar bone to the root canals. The perforated canals in Group I were filled with gutta-percha and root canal cements; Calxyl (Calcium Hydroxide in Ringer's solution), Zinc Oxide -Eugenol cement (Z.O.E.), Kerr sealer (Rickert's paste) and AH 26 (Epoxy Resin preparations). The perforated canals in Group II were sealed with Calxyl, Z.O.E, Kerr sealer and AH26. Histologic examinations of periodontal tissue reactions were observed at various time intervals. The results were as follows; l. Cementum deposition on the perforated root surface in Group II cases showed slightly earlier than that of Group I. Healing tendency of injured alveolar bone in Group II was greater than that of Group I. 2. According to the time increase after experiment, the cementum deposition on the site of perforated dentin in Group II with intact pulp was notably thickened. Secondary dentin deposition on the root canal surface where the dentinal tubles were cut was also found in similar pattern. 3. In the cases of perforated canals sealed with Calxyl both in Group I and Group II, It revealed the earliest cementum-deposition among 4 different root canal cements. In the cases of perforated canals sealed with Kerr sealer and AH26, the cementum-deposition on the root surface was not found. 4. Proliferation of epithelium around the perforated area was first seen at 5-week cases in Group I, and at 3-week cases in Group II. 5. In all cases, dentin resorption on the site of perforated root surface was always occured.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.286-298
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• 1999

The endodontic-periodontic combined lesions have been difficult to get correct diagnosis and predictable treatment. This study was to make the experimental endodontic-periodontic combined defects in dogs for the study of the periodontal regeneration and to evaluate the efficacy of the enamel matrix protein and e-PTFE membrane in the experimental endodontic-periodontic combined defects. 5 mongrel dogs were used. The pulp chambers were opened and the plaque was inserted into the chambers to induce the periapical lesions on the mandibular second, third and fourth premolars of the dogs. 1 month later, the root canal treatments were done with gutta perch a and ZOE sealer. On the day of surgery, the periapical defects were standardized by trephine bur. The buccal dehiscence defects were made by the dental bur and bone chisels. The apicoectomy with retrofilling was done. The prepared roots were randomly selected for test and control groups. In the experimental groups, the enamel matrix derivative and e-PTFE membrane were used. Nothing was placed on the control group. Fluroscent labelling was used to evaluate the bone formation. After 4 and 12 weeks, the dogs were sacrificed and undecalcified sections were prepared and stained with toluidine blue. Those histologic sections were examined by fluorescent microscopy and light microscopy. The results were as follows. 1. In the control group, new bone was formed in the periapical defects and scarcely in the buccal dehiscence defects. New cementum was not detected at 4 and 12 weeks. 2. In the experimental groups, new bone, new cementum and periodontal ligament were found in the periapical and buccal dehiscence defects. The relative amount and the quality of the new bone, new cementum and periodontal ligament tissue that had formed on the experimental groups were superior to those of the control group. 3. The current observation implicated that e-PTFE membrane and enamel matrix protein could be the effective tools for the guided tissue regeneration of the endo-perio combined defects.

• Journal of The Korean Dental Society of Anesthesiology
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• v.11 no.1
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• pp.16-21
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• 2011

Background: Since introduced by Gow-Gates GA in 1973, Gow-Gates mandibular nerve block (GMNB) has played an important role in the area of dental local anesthesia. However, compared to the conventional inferior alveolar nerve block (IANB), this technique seems to fail to attract the attentions of general practitioners in South Korea. The aim of this study was to prove the clinical real value, mainly the anesthetic efficacy, of GMNB in minor oral surgery. Methods: The study group comprised 40 patients (15 males and 25 females) who were randomly allocated to receive GMNB or IANB for extraction of third molars. Both techniques utilized two 1.8 ml dental cartridges of 2% lidocaine including 1:100,000 epinephrine for each patient. Pulpal and gingival tissue anesthesia of mandibular premolars and molars were recorded at 0, 15 and 40 minutes after administration of local anesthetics using both an electric pulp tester and a sharp dental explorer. Results: The success rates of pulpal and gingival tissue anesthesia in the IANB group were not significantly different from the GMNB group in overall efficacy. Patient's and operator's satisfaction ratings were also not significantly different between two groups. Interestingly, the injection pain of GMNB group was significantly lower than that of IANB group. Conclusion: This study demonstrated that the anesthetic efficacy of pulpal and gingival tissue of GMNB was not inferior to that of IANB. The GMNB could be a good alternative of the IANB in most of minor oral surgical procedures.

• The Journal of Korean Academy of Prosthodontics
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• v.8 no.1
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• pp.90-94
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• 1968

The author attempted to study the role of liners as a barrier against the penetration of the acids released from the liquid of dental cements. Six different kinds of liners were used in this study and the depth of penetration of the acids of phosphate and silicate cements were measured ands following conclusions were obtained. 1. All the liners successfully prevented penetration of the acids released from phosphate and silicate cements. 2. When silicate cements were placed into the cavity without any liners, free acids were liberated continuously and thus may give injuries to the pulp tissue.

• Restorative Dentistry and Endodontics
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• v.40 no.4
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• pp.314-321
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• 2015

Tooth related factors such as palatoradicular groove can be one of the causes for localized periodontal destruction. Such pathological process may result in apicomarginal defect along with inflammation of pulp. This creates challenging situation which clinician must be capable of performing advanced periodontal regenerative procedures for the successful management. This case report discusses clinical management of apicomarginal defect associated with extensive periradicular destruction in a maxillary lateral incisor, along with histopathologic aspect of the lesion.

• The Journal of the Korean dental association
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• v.55 no.8
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• pp.565-573
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• 2017

Root canal perforations are defined as the communication between the pulp cavity, the periodontal tissue and alveolar bone. The occurrence of perforations during endodontic treatment is reported to range from 2.3%~12%, which is not a complication rarely happens. Perforations have iatrogenic or pathological etiologies that involve caries or resorption. It leads to inflammation and the destruction of periodontal fibers and alveolar bone, followed by periodontal defects. Mineral trioxide aggregate (MTA) is currently the most indicated material for repair of root perforation, because of its favorable biocompatibility and sealing ability. Using magnification with dental operating microscope enhance the accessibility and visibility to manage the root perforation. It is important to diagnose and repair perforations immediately if possible.

• Journal of Life Science
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• v.8 no.4
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• pp.443-448
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• 1998

We analyzed lignin content and wxpression of OMT gene during growth season in two hybrid poplar species. OMT gene expression was observed mainy in the developing secondary xylem where major quantity of lignin occurs. Lignin content in the xylem tissue increased as plant resumed growth in the spring and reached the highest in the late August. Change in lignin content was concurrent with that of OMT gene expression, indicating OMT is a key enzyme in lignin biosynthesis.

• Restorative Dentistry and Endodontics
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• v.1 no.1
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• pp.8-10
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• 1975

This study is to determine or detect deposition of mercury particles emitted from dental amalgam fillings. Amalgam fillings were carried out routinely on the dogs' teeth. (CIV cavities) Mercury which contains about 200${\mu}Ci$ of $^{197}Hg$ was employed on this purpose in each cavity. Radioactivity was measured by means of well type scintillation counter from saliva and mucous membrane of surrounding tissue. The C. P. M. value from the saliva was highest, mucous membrane was moderate and least on blood and fecs, as shown table on I. II. III. IV. 1. C.P. Mvalue from Saliva reveals 114 to 135 (lowest and highest) throughout the measuring period until 41 hours. 2. From blood samples no significant value was found. 3. CPM value from feces at2nd day and 4th day was about 90. 4. The highest and lowest CPMvalue from marginal gingiva was 465 and 209 respectively. Palatine showed 281 and 189, esophagus 179 and 165, and pulp from experiment tooth 190 and 104 respectively.

• The Journal of the Korean dental association
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• v.52 no.2
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• pp.85-95
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• 2014

Completely avulsed tooth caused by a traumatic injury needs replantation for treatment choice. But, replantated tooth usually comes with inflammatory root resorption, replacement resorption and ankylosis, moreover ankylosis cause severe functional and esthetic problems. The outcome of replantated tooth depends on the following factors; minimal damage to pulp and periodontal tissue, the length of extraoral time, the medium of the tooth stored, the level of root formation and so on. The purpose of this case report is to describe the variable resorption pattern and to discuss types that influence the occurrence of resorption.