• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.516-522
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• 2008

In the case of the impacted teeth, the clinician has to consider development of tooth, site of impaction, eruption path, and cooperation of patient. If there are genetic or general factors to effect the eruption of tooth, the clinician treats these first and then takes the early treatment for eruption guidance. If there are physical factors to intercept eruption, the clinician put them off first. However, if there are no factors to effect eruption of tooth and enough space for eruption, the clinician can consider extraction of deciduous teeth, forced eruption and surgical reposition. In case of surgical repositioning, proper time for root development, proper socket formation, and minimal trauma are important for success. This case presents displaced impacted maxillary central incisor with dilacerated root. The development of root is Nolla's stage 7, and the tooth was treated by surgical repositioning. We can observe no root resorption and good healing pattern.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.399-406
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• 2011

Traumatic injury on tooth occurs frequently among trauma patients, and mainly occurs on tooth with premature roots which influences pulp tissue, periodontal ligament, alveolar bone, and Hertwig's epithelial root sheath. According to the degree of trauma, a number of kinds of healing process can be observed, such as complete re-vascularization of pulp, root canal obliteration, growth suspension of root apex, and invasion of alveolar bone into root canal, and there can be some complications such as necrotic change of inflammatory root resorption and partial pulp necrosis due to pulp necrosis toward complete necrosis. In this clinical case, 3 patients who had traumatic injury showed root growth suspension and alveolar bone invasion into root canal due to proliferation of periodontal ligament cell and osteocyte at the base of extraction socket into pulp chamber because of the injury on Hertwig's epithelial root sheath. If intrusion of alveolar bone into root canal due to injury on Hertwig's epithelial root sheath after having traumatic injury doesn't show any complication, the pulp may be considered to have normal vitality and doesn't need any further treatment, therefore differential diagnosis is very necessary. However, it may be accompanied with suspension of root growth, therefore, additional trauma during the treatment of injured tooth should not be applied.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.1
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• pp.1-8
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• 2014

Purpose: The purpose of this study was to investigate the effect of head position changes on vertical and horizontal magnification in dental panoramic radiographs. Materials and Methods: Five 4 mm metal balls were placed above alveolar crest of dry skull considering extraction socket and dental arch. Panoramic radiographs were taken by OP-100D (Instrumentarium Imaging Co., Tuusula, Finland) at proper and rotated head position along the sagittal and transverse axis at 3 - $20^{\circ}$ upwardly, downwardly, to the left and to the right rotation. Images were stored in DICOM files and were measured by ruler equipped within INFINITT PACS software. Results: The mean horizontal magnification was $1.22{\pm}0.01-1.44{\pm}0.01$ and mean vertical magnification was $1.29{\pm}0.00-1.35{\pm}0.02$ at standard head position. There was statistical significance of horizontal magnification between the anterior ($1.24{\pm}0.02-1.31{\pm}0.03$) and the posterior area ($1.40{\pm}0.03-1.33{\pm}0.02$) (P < 0.05). Vertical magnification resulted in less variation ($1.24{\pm}0.01-1.37{\pm}0.02$) than horizontal magnification ($0.88{\pm}0.03-3.73{\pm}0.16$) according to the rotation. There was statistical significant difference on horizontal magnification (P < 0.05). Conclusion: In rotated head position, the horizontal magnification should be considered because these can cause distortion on panoramic radiographs.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.3
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• pp.249-258
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• 2013

The purpose of this study was to investigate how image magnification in dental panoramic radiography is influenced by object position. Five metal balls (4 mm in diameter, 2 for the anterior and 3 for the posterior region on the right side) were placed above alveolar crest of dry skull considering extraction socket and dental arch. Dry skull was radiographed using OP-100D (Instrumentarium Imaging Co., Tuusula, Finland) at proper and displaced position along the sagittal and transverse plane at 3 mm, 6 mm, 9 mm, 12 mm and 15 mm using special mount which can control precise movement. Images were stored in DICOM files and were measured by ruler equipped within INFINITT PACS software (Infinitt Co., Ltd., Seoul, Korea). The mean horizontal magnification was 1.224-1.439 and mean vertical magnification was 1.286 - 1.345 at proper position. Vertical magnification resulted in less variation (1.245-1.418) than horizontal magnification (0.798-6.297) according to the sagittal and transverse displacements. Head positioning is important for linear measurement on panoramic radiography and inclusion of standard object (for instance, metal ball) is helpful to anticipate exact magnification of panoramic radiographs at various location.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.135-143
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• 1996

The aim of this study was to evaluate bone promotion of bioreabsorbable guided tissue regeneration for generating new bone adjacent to osseointegrated implants in dogs. Third premolars were extracted in dgo mandibles. Cylindrical HA-coated implants were placed into extracted sockets in dogs. And test sites were protected by $GUIDOR^{(R)}$ matrix barrier. But control sites were not protected by membrances. The sites were examined clinically, radiologically, and histologically after 1, 2, and 4 months to assess bone regeneration. The results obtained were as foolows : 1. There were the good healing and the stability of $GUIDOR^{(R)}$ matrix barrier in experimental site during the healing period. 2. Complete resorption of $GUIDOR^{(R)}$ matrix barrier was clinically observed about 4 months postoperatively. 3. The woven bone changed to mature bone with a normal cortical plate and mature, resting periosteum after 4 months. 4. In experimental site, there was a significantly greater bone promtion than observed in control site. 5. $GUIDOR^{(R)}$ matrix barrier was useful for the preparation of immediate dental implants.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.1
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• pp.15-24
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• 2016

It is considered an implant failure when there is esthetic problems in the anterior area although the prosthesis function normally. In 2003, Dr. Kan et al stated that implant bone level is determined by the adjacent teeth. After that many scholars have studied how can achieve the esthetics result on adjacent teeth bone loss cases. In 2012, Dr. Takino published an article in Quintessence. He summarized previous articles and reclassified the defects from class 1 through 4. Class 1 and 2 depicts a situation where there is no bone loss on adjacent teeth. In Class 3 and 4, interproximal bone loss extends to the adjacent tooth. If one side is involved, it is Class 3. If both sides are involved, it is Class 4. The clue for esthetic implant restoration is whether bone loss extends to adjacent tooth or not. If the bone level of adjacent tooth is sound, we can easily achieve the esthetic but the bone level is not sound, the surgery will be complicated and the esthetic result will be unpredictable. So regenerative surgery for adjacent tooth is necessary for long-term maintenance. But the options and process were so complicated, the purpose of this article is to report the method simplify the surgery and gain a similar outcome.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.385-391
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• 2003

The purpose of this study is to examine the viability of PDL cells in rat molars by using MTT assay and to verify the MTT assay through the histologic observation. Thirty of Sprague-Dawley white female rats of 4-weeks old with a body weight of about 100 grams were used. Groupings are as follows : Immediate Group : Positive control group(n=10)-after extraction immediately. Dried Group : Negative control group(n=10)-after drying for an hour under warm dry. $ViaSpan^{\circledR}$ Group : 1hour $ViaSpan^{\circledR}$ group(n=10)-after storing in $ViaSpan^{\circledR}{\;}at{\;}4^{\circ}C$ for 1hour. Ten teeth of each group were treated as same as above and replanted to the original socket of experimental animals. After two weeks of replantation. all the experimental animals were sacrificed. And after fixation, extracted maxillary jaw was dimineralized. After it was embedded in paraffin. serial section by $5\mu\textrm{m}$ was carried out and for construction of specimen, hematoxylin-eosin dye was used. The mean MTT measurement of immediate group(positive control) is 2.81 and the mean measurement of dried group(negative control) is 0.98 which is significantt differnt(P<0.05), The mean measurement of $ViaSpan^{\circledR}$ group is 2.65 and there is significant difference between dried group and $ViaSpan^{\circledR}$ group(P<0.05), However, there is no difference between immediate group and $ViaSpan^{\circledR}$ group. The average resorption points of immediate group is 3.03 points. In the dried group, average 6.44 points resorption and 2.68 points showed resorption in the $ViaSpan^{\circledR}$ group. Unlike with MTT assay, there was no significant difference between the immediate group and $ViaSpan^{\circledR}$ group. The usage of MTT assay as a viable cell marker may give us a better indication of the maintenance of periodontal ligament cell vitality.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.267-275
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• 2023

To obtain better esthetic results when immediately placing a dental implant, the soft tissue surrounding the implant must be conditioned during healing of the extraction socket. To this end, the emergence profile can be customized through immediate restoration of the provisional prosthesis, and good clinical results can be obtained at the time of definitive restoration in the future, resulting in high patient satisfaction. In this case, horizontal root fracture occurred after trauma to both maxillary central incisors. Immediate implant placement and loading was planned considering aesthetics and alveolar bone condition. By taking an impression using a digital intraoral scanner, a digital diagnostic wax-up was performed to make a more aesthetic prosthesis without applying external force to the traumatized teeth. Based on this, the ideal placement location was determined and immediate implant placement was performed using a 3D printed surgical guide. The provisional prosthesis was restored 5 days after placement, and the definitive zirconia crown was restored through soft tissue conditioning and customization using the shape of the provisional prosthesis for 3 months.

• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.455-466
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• 2002

The objective of this study was to evaluate the changes that occurred over time in the distracted periodontal ligament space following the rapid retraction of a tooth by periodontal distraction after bone undermining surgery had been conducted in the dogs. The upper second premolars were extracted on the left and right side in 4 male beagle dogs. Immediately after extraction, the interseptal bone distal to the upper first premolar was thinned and undermined by grooving to decrease the bone resistance. Activating an individualized distraction appliance at the rate of 0.225mm twice a day, the upper first premolar was retracted rapidly toward the extraction socket. Periodontal distractions were performed for 5, 10, and 20 days, and 20-day-distraction cases were followed by maintenance periods of 0, 14, 28, and 56 days. After 20 days of rapid retraction, the average distal movement of the upper first premolar was 5.02mm, and the average mesial movement of the upper third premolars serving as an anchorage unit was 0.18 mm. On histological examination, the regeneration of bone occurred in a highly organized pattern. Distracted periodontal ligament space was filled with newly formed bone oriented in the direction of the distraction, and this was followed by extensive bone remodeling. This result was similar to those observed in other bones after distraction osteogenesis. In the periodontal ligament, the relationship between collagen fibers and cementum began to be restored 2 weeks after the distraction was completed, and showed almost normal features 8weeks after the completion of the periodontal distraction. However, on the alveolar side, the new bone formation was still in process and collagen fiber bundles and Sharpey's fibers were not present 8 weeks after the completion of the periodontal distraction. Reactions in the periodontal ligament of the anchorage tooth represented bone resorption on the compressed side and new bone deposition on the tension side as occurred in conventional orthodontic tooth movement. In conclusion, the results of this study showed that periodontal structures on the distracted side of the periodontal ligament were regenerated well histologically following rapid tooth movement.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.205-215
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• 2008

The purpose of this study is to evaluate at which stage of tooth germ would develop into normal calcification and hence to increase the success rate of transplantation. Therefore, tooth germs on the 15th, 17th embryonic day and the 3rd day of birth were separated for allotransplantation into maxilla of adult rat of 11 weeks. Calcification processes were analyzed radiographically and histopathologically at 4 weeks and 8 weeks after allotransplantation. The results are as follows: 1. Allotransplanted tooth germ at 4 weeks and 8 weeks showed delayed calcification compared to that of normal odontogenesis. 2. At 4 weeks, abnormal calcified tissue, such as odontoma and ankylosis of osteodentin with surrounding alveolar bone were observed. 3. At 8 weeks, allotransplanted tooth germs of the 15th and 17th embryonic day showed calcification and osteodentin surrounded by periodontal ligament. 4. At 8 weeks, allotransplanted tooth germs of the 3rd day of birth showed calcification composed of cementum and osteodentin. In this study, we observed small sized and amorphous calcified tissue from allotropic allotransplantation of tooth germs. Since these calcified tissue were underdeveloped and shaped irregularly, for calcification into normal tooth form, further study needs consideration about the reduction of surgical trauma, developmental stage of transplanted tooth germ, blood supply from recipient site, fixation method in transplanted site and period of transplantation.