• The korean journal of orthodontics
• /
• v.31 no.3 s.86
• /
• pp.369-379
• /
• 2001

The aim of this study was to investigate the periodontal response according to the timing of orthodontic force application after bone graft into the angular bony defect. Nine dogs were divided into three groups, 2, 4, and 6 weeks, according to the timing of orthodontic force application after bone graft. Periodontal angular bony defects were created surgically at the distal aspect of both maxillary third incisors. Two weeks later, flap operation was performed to eliminate inflammation and reference notch was made on the root surface at the level of the bottom of each defect. Demineralized freeze-dried bone was implanted on the left side whereas only debridement was done on the other side. Experimental tooth movement was executed during 8 weeks on both graft and non-graft sides. After 2 weeks of retention period, animals were sacrificed for histologic specimens. The results were obtained as follows 1 New bone formation was more pronounced in the graft side than in the non-grad side in all experimental animals. 2. In the 6-week group, new bone and cementum formation was observed in more than half from the notch to the cemento-enamel junction, and the zone of connective tissue attachment was found without apical migration of junctional epithelium. 3. In the 4-week group, the amount of new bone formation was smaller than in the 6-week group whereas the overall remodeling pattern was similar. 4. New bone formation was confined to around the notch and the junctional epithelium migrated apically to the level of the notch with no connective tissue attachment and cementum formation in the 2-week group. The results of the present study suggest that periodontal response may be influenced by the timing of orthodontic force application after bone graft into angular bony defect.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.2
• /
• pp.213-230
• /
• 2008

The aim of this study was to analyze the initial movement and the stress distribution of each tooth and periodontal ligament during the lingual lever-arm retraction of 6 maxillary incisors using FEA. Two kinds of finite element models were produced: 2-properties model (simple model) and 24-properties model (multi model) according to the material property assignment. The subject was an adult male of 23 years old. The DICOM images through the CT of the patient were converted into the 3D image model of a skull using the Mimics (version 10.11, Materialise's interactive Medical Image Control System, Materialise, Belgium). After series of calculating, remeshing, exporting, importing process and volume mesh process was performed, FEA models were produced. FEA models are consisted of maxilla, maxillary central incisor, lateral incisor, canine, periodontal ligaments and lingual traction arm. The boundary conditions fixed the movements of posterior, sagittal and upper part of the model to the directions of X, Y, Z axis respectively. The model was set to be symmetrical to X axis. Through the center of resistance of maxilla complex, a retraction force of 200g was applied horizontally to the occlusal plane. Under this conditions, the initial movements and stress distributions were evaluated by 3D FEA. In the result, the amount of posterior movement was larger in the multi model than in the simple model as well as the amount of vertically rotation. The pattern of the posterior movement in the central incisors and lateral incisors was controlled tipping movement, and the amount was larger than in the canine. But the amount of root movement of the canine was larger than others. The incisor rotated downwardly and the canines upwardly around contact points of lateral incisor and canine in the both models. The values of stress are similar in the both simple and multi model.

• Journal of Oral Medicine and Pain
• /
• v.33 no.1
• /
• pp.15-26
• /
• 2008

Purpose : To investigate the actual conditions of diagnosis and treatment of oral medicine inpatient with systemic disease. Methods : A total of 110 subjects, inpatient due to systemic disease for diagnosis and treatment of oral disease was requested to answer the medical history and dental treatment record. Results : Systemic disease is composed of Non-insulin-dependent diabetes mellitus 26%, Cerebral infarction 25.2%, Intracerebral hemorrhage, Polyarthrosis, Coxarthrosis 4.7%, Nerve root and plexus disorders, Hypertensive heart and renal diseases, Ankylosing spondylitis 2.4%. Chief complain of oral disease is composed of toothache 28.6%, routine check 23%, tooth mobility 8.7%, hypersensitivity 7.1%, periodontal bleeding 6.4%. Oral disease is composed of Gingivitis and periodontal diseases 28.9%, Dental caries 17.1%, Diseases of pulp and periapical tissues 15.1%, Diseases of salivary glands 10.5%, Other diseases of hard tissues of teeth 8.6%, Within Normal Limit 5.3%. Treatment of oral disease is composed of periodontal treatment 17.95%, rejection of treatment 16.67%, medication for halitosis & dry mouth 13.46%, extraction 12.18%, prosthetic treatment 8.97%. Chief complain in oral medicine is composed of oral soft tissue problem 6.4%, craniomandibular disorders 5.6%, halitosis 4%, total 16%. Conclusion : These findings indicate that inpatient due to the systemic disease is significantly correlated to the oral disease. The patients of oral disease interrelationship between inpatient and outpatient of systemic disease should be validated by future research.

• The Journal of Korean Academy of Prosthodontics
• /
• v.52 no.2
• /
• pp.74-81
• /
• 2014

Purpose: While studies have examined microleakage in endodontically treated teeth restored with posts, microleakage among post and adhesive systems remains a concern. This study compared the sealing properties of 3 adhesively luted post systems. Materials and methods: Thirty-six endodontically treated permanent maxillary central incisors were divided into 3 groups: Zirconia-glass fiber, Quartz-glass fiber, Polyethylene fiber posts. Post space was prepared and each post was adhesively luted with 3 systems. The specimens were separately immersed in freshly prepared 2% methylene blue solution for 1 week. The cleaned specimens were then embedded in autopolymerizing acrylic resin. The root portion of tooth were horizontally sectioned into three pieces (apical, middle, and coronal portions). An occlusal view of each section was digitally photographed with a stereomicroscope. The methylene blue-infiltrated surface for each specimen was measured. Dye penetration was estimated as the ratio of the methylene blue-infiltrated surface to the total dentin surface. Results: No significant differences were found among post types. The variables of middle section and 3-stage adhesive produced significant differences in microleakage between the following post pairs: zirconia-glass fiber versus quartz-glass fiber, zirconia-glass fiber versus polyethylene fiber, and quartz-glass fiber versus polyethylene fiber (P<.05). There were significant differences between the apical and coronal sections of each post type, and between apical versus middle sections of quarze-glass fiber and polyethylene fiber posts (P<.05). Conclusion: No significant differences were found among post types. The 3-stage adhesive produced significant differences in microleakage between the following post pairs.

• Journal of Periodontal and Implant Science
• /
• v.23 no.3
• /
• pp.577-594
• /
• 1993

The ultimate goal of periodontal therapy is the regeneration of the periodontium that have been destroyed as a result of periodontal disease. This study were done in order to determine the healing status of periodontium under Polytetrafluoroethylene and millipore fillter combined with fibrin and the effect of the guided tissue regeneration procedures were performed as follows : 1) flap operation using PTFE membrane(control group) 2) flap operation using PTFE membrane which was fixed with fibrin(experimental group 1) 3) flap operation using millipore filter which was fixed with suture(experimental group II) 4) flap operation using millipore filter which was fixed with fibrin(experimental group II) After 1, 2, 4, 8, 12 weeks, dogs were sacrificed by perfusion technique and tissue block was excised including the tooth and prepared for light microscope with H-E & Masson’s trichrome staining. The result were as follows : In control and experimental group, there is no siginificant difference on epithelial cell down growth within 1st week, but more epithelial cell downgrowth in millipore or millipore combined with fibrin group. In this experiment, there were no significant difference in new cementum and alveolar bone formation whether PTFE membrane was fixed with suture or fibrin. In control and each experimental group, bone maturation appeared in 4 weeks, bone width increased bucco-lingually in control and experimental 1 group especially. Both control group and experimental group showed mild mew cementum formation on root surface and irregular arrangement of collagen fiber at 4 weeks, that showed obvious increased cementum formation at 8 weeks, and that was observed the functional arrangement of collagen fiber between new cementum and new alveolar bone at 12 weeks.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.27 no.4
• /
• pp.540-548
• /
• 2000

The aim of this study was to evaluate the timing of sequence of tooth calcification in current Korean growing children. The Calcification stage of permanent teeth of Korean children was investigated by classifying them into 10 stages by the criteria of Nolla, using the panoramic radiographs of 258 healthy Korean children, 149 males and 109 females, between the ages of 4 years and 13 years, with normal growing tendency and no orthodontic treatment experience. The obtained results were as follows: 1. Timing of calcification of permanent teeth by Nolla stage was established with mean values. Among the mean value, results of Nolla stage 7 were as follows: Calcification timing of male in the maxilla was 6 year 9 month on central incisor, 7 year 4 month on lateral incisor,7 year 9 month on canine, 8 year 8 month on the first premolar, 9 year 4 month on the second premolar, 6 years 3 month on the first molar and 10 year 8 month on the second molar, calcification timing of male in the mandible was 5 year 11 month on central incisor, 6 year 4 month on lateral incisor, 7 year 5 month on canine, 8 year 1 month on the first premolar, 8 year 6 month on the second premolar 5 years 6 month on the first molar and 10 year 3 month on the second molar. Calcification timing of female in the maxilla was 6 year 2 month on central incisor, 6 year 7 month on lateral incisor, 6 year 11 month on canine, 8 year 1 month on the first premolar, 8 year 5 month on the second premolar, 5 years 10 month on the first molar and 9 year 10 month on the second molar, calcification timing of male in the mandible was 5 year 6 month on central incisor, 5 year 9 month on lateral incisor, 6 year 8 month on canine, 7 year 6 month on the first premolar, 8 year 4 month on the second premolar, 5 years 3 month on the first molar and 9 year 7 month on the second molar. 2. The sequence of calcification at Nolla stage 7 was in consequence to the first molar, central incisor, lateral incisor, canine, the first premolar, the second premolar and second molar. 3. While the sequence of root completion of maxilla was in consequence to the first molar, central incisor, lateral incisor, that of mandible was in order of central incisor, first molar and lateral incisor. 4 the calcification timing of permanent teeth was earlier in female than in male (p<0.05). According to above data, the result of this study is applicable for diagnosis and routine clinical practice for children.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.1
• /
• pp.77-94
• /
• 2021

The purpose of this study was to investigate the three-dimensional characteristics of mesiodens using Cone-beam Computed Tomography(CBCT) and analyze the factors affecting complications and anesthetic methods of extraction. This study evaluated 602 mesiodens of 452 patients who underwent extraction of mesiodens at the department of Pediatric Dentistry in Seoul National University Dental Hospital between 2017 and 2019. The ratio of mesiodens patients over total patient per year was gradually increased over the past 20 years. Mesiodens with labio-palatally horizontal direction while root directing labial were the most common among the mesiodens with horizontal direction. Mesiodens were the most common at the cervical side of the adjacent teeth(37.0%) and mesiodens located in the near-palatal side were observed about 3.83 times higher than the far-palatal side. Most of the mesiodens(82.1%) were in contact with adjacent permanent teeth on all three sides of the CBCT and 46.2% of mesiodens had curved roots. The patient's age, vertical position, presence of complications, and proximity showed a significant difference in the selection of general anesthesia among anesthetic methods. The direction and vertical position of mesiodens had a significant effect on complications. These results provide a better understanding of mesiodens for establishing an accurate diagnosis and treatment plan.