• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.10 no.1
• /
• pp.22-25
• /
• 2014

Fibrous dysplasia(FD) is a benign fibro-ossifying disease in which fibrous tissue replaces normal bone and marrow. Craniofacial bones, including the maxilla and mandible, are commonly involved. A 7 year-old girl visited the clinic with a chief complaint of gingival swelling around the lower left primary molar. Mild bulging of the lower left periodontal tissue was observed. Not only the mandible, but also the maxilla, zygoma, sphenoid, and temporal bones were affected by FD. Permanent tooth germs were involved in the lesions and facial asymmetry was caused by lower left bone expansion. She was scheduled for a follow-up visit at the department of pediatric dentistry and oromaxillofacial surgery.

• The korean journal of orthodontics
• /
• v.35 no.3 s.110
• /
• pp.238-249
• /
• 2005

The contemporary two-jaw surgical approach usually involves a Le Fort osteotomy of the maxilla and a ramal osteotomy of the mandible with 3-dimensional repositioning of the jaws as well as the occlusal planes. After making the surgical treatment plan. the surgical movements are duplicated in the model surgery. During this procedure, reference poings and lines are drawn on the base of the models over the dental arch and sawcuts are mads according to these marked osteotomy lines. This technique, however, has been found to be inexact. especially when the laws are moved in several dimensions simultaneously. To overcome this. different methods have been developed for an accurate repositioning of the jaws as planned. A new appliance. Surgical Jaw Relater, has been devised by th8 author for the simple 3-dimensional relocation of the upper and lower models, resulting in the easy construction of the splints such as centric relation splint, intermediate and final splint. This article describes an introduction and a clinical application of this appliance. Through the application of this system to the orthognathic cases including two-law surgery. it is proved that the row device is very clinically useful.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.1
• /
• pp.46-51
• /
• 2004

Talon cusp is cusp-like structure that develops additionally in crown of anterior tooth. And it is one of dental anomalies. Talon cusp can cause various diagnostic, functional, aesthetic problems depending on the size and configuration of cusp. there is a tendency for caries to occur in the developmental grooves, and advanced attrition, periodontal problems, irritation the tongue and temporomandibular pain, occlusal interference and displacement of affected tooth may result. Therefore, early diagnosis and appropriate treatment of each case is important so that it minimize local problems, such as caries, periodontal diseases, and malocclusion. These cases which are in permanent and primary anterior teeth are about gradual reduction forming reparative dentine and complete reduction of talon cusp and root canal therapy which is an alternative and effective form of treatment when gradual reduction of talon cusp may not be possible.

• Journal of Periodontal and Implant Science
• /
• v.27 no.1
• /
• pp.179-189
• /
• 1997

Teeth mobility is an important part of a periodontal examination, because it represents a function of the persisting height of the alveolar bone and the width of the periodontal ligament. The purpose of this study was to evaluate clinical difference in teeth mobility after treatment with the modified Widman flap and the undisplaced flap in humans. Twenty males with moderate periodontal disease were selected. The severity of periodontal disease was evaluated with sulcular bleeding index, pocket depth and attachment level and tooth mobility was measured with Periotest(Siemens Co., Germany) at the initial examination, 1, 2, 4, 6, 8 and 12 weeks following the modified Widman flap and the undisplaced flap operation using the split-mouth technique. The relation of mobility to clinical parameters was statistically analyzed by multiple regression and the change of teeth mobility according to healing process by independent t-test using SPSS program. The results were as follows: 1. There was a strong relationship between the Periotest value(PTV) and attachment level. 2. The change of teeth mobility in both flap procedures was increased significantly at 1 week post-op. and was decreased to preoperative level at 4 weeks post-op, in modified Widman flap and at 6 weeks post-op. in undisplaced flap. 3. The change of teeth mobility in premolar teeth group in undisplaced flap compared to modified Widman flap was generally increased but these changes were not statistically significant. The changes of teeth mobility in molar teeth group in undisplaced flap was increased significantly at 2 weeks post-op.. 4. The change of teeth mobility following undisplaced flap was increased significantly compared to that of modified Widman flap at 2 weeks post-op.

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.15 no.1
• /
• pp.89-93
• /
• 2019

Preterm infants have higher possibility of undergoing endotracheal intubation after birth than normal children due to medical conditions. Developmental disturbances of primary incisors following intubation can occur as crown malformation, enamel defects, delayed eruption, displacement of dental follicle in crypt, groove formation of palate or alveolar ridge, acquired cleft palate, and dental arch distortion. This clinical report presents the effect of intubation on primary dentition of preterm infants. A 2-year-old girl with cerebral palsy and premature birth history visited our clinic with chief complaint of unerupted primary upper incisor. A 1-year-old boy with cerebral palsy, status epilepticus and premature birth history visited our clinic due to crown malformation. Developmental disturbances of primary incisors in these cases were not related to the patients' systemic disease, and there were no history of dental trauma. A long term endotracheal intubation prior to tooth eruption might have caused local trauma on alveolar ridge. It is very important to monitor dental problems of preterm infants who had experienced endotracheal intubation during neonatal period. Due to influences on both primary and permanent teeth, periodic re-evaluation of affected areas and establishment of comprehensive treatment plans are necessary.

• The korean journal of orthodontics
• /
• v.34 no.5 s.106
• /
• pp.417-428
• /
• 2004

The purpose of this study was to evaluate the stress distributions at the periodontal ligament (PDL) and displacements of the maxillary first molar when mesially directed force was applied under various molar angulations and rotations. A three dimensional finite element model of the maxiilary first molar and its periodontal ligament was made Upright position, mesially angulated position by $20^{\circ}$ and distally angulated position of the same degree were simulated to investigate the effect of molar angulation. An anteriorly directed force of 200g countertipping moment of 1,800gm-mm (9:1 moment/force ratio) and counterrotation moment of 1,000gm-mm (5:1 moment/force ratio) were applied in each situation. To evaluate the effect of molar rotation on the stress distribution, mesial-in rotation by $20^{\circ}$ and the same amount of distal-in rotation were simulated. The same force and moments were applied in each situation. The results were as follows: In all situations, there was no significant difference in mesially directed tooth displacement Also, any differences in stress distributions could not be found, in other words. there were no different mesial movements. Stress distributions and tooth displacement of the $20^{\circ}$ mesially angulated situation were very similar with those of the $20^{\circ}$ distal-in rotated situation. The same phenomenon was obserned between the $20^{\circ}$ distally angulated situation and $20^{\circ}$ mesial-in rotated situation. When the tooth was mesially angulated, or distal-in rotated, mesially directed force made the tooth rotate in the coronal plane. with its roots moving buccally, and its crown moving lingually. When the tooth was distally angulated, or mesial-in rotated, mesially directed force made the tooth rotate in the coronal plane, with its roots moving lingually and its crown moving buccally. When force is applied to au angulated or rotated molar, the orthodontist should understand that additional torque control is needed to prevent unwanted tooth rotation in the coronal plane.

• Restorative Dentistry and Endodontics
• /
• v.30 no.2
• /
• pp.128-137
• /
• 2005

In this study we measured the amount of light energy that was projected through the tooth material and analyzed the degree of polymerization by measuring the surface hardness of composites. For polymerization, Optilux 501 (Demetron, USA) with two types of light guide was used: a 12 mm diameter light guide with 840 nW/$cm^2$ light intensity and a 7 mm diameter turbo light guide with 1100 nW/$cm^2$. Specimens were divided into three groups according to thickness of penetrating tooth (1 mm, 2 mm, 0 mm). Each group was further divided into four subgroups according to type of light guide and curing time (20 seconds, 40 seconds). Vickers' hardness was measured by using a microhardness tester. In 0 mm and 1 mm penetrating tooth group, which were polymerized by a turbo light guide for 40 seconds, showed the highest hardness values. The specimens from 2 mm penetrating tooth group, which were polymerized for 20 seconds, demonstrated the lowest hardness regardless of the types of light guides (p < 0.05). The results of this study suggest that, when projecting tooth material over a specified thickness, the increase of polymerization will be limited even if light intensity or curing time is increased.

• Journal of Periodontal and Implant Science
• /
• v.23 no.3
• /
• pp.535-563
• /
• 1993

New techniques for regenerating the destructed periodontal tissue have been studied for many years. Current acceptable methods of promoting periodontal regeneration alre basis of removal of diseased soft tissue, root treatment, guided tissue regeneration, graft materials, biological mediators. Platelet-derived growth factor (PDGF) is one of polypeptide growth factor. PDGF have been reported as a biological mediator which regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purposes of this study is to evaluate the possibility of using the PDGF as a regeneration promoting agent for furcation involvement defect. Eight adult mongrel dogs were used in this experiment. The dogs were anesthetized with Pentobarbital Sodium (25-30 mg/kg of body weight, Tokyo chemical Co., Japan) and conventional periodontal prophylaxis were performed with ultrasonic scaler. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree III furcation defect was made on mandibular second(P2) and fourth(P4) premolar. For the basic treatment of root surface, fully saturated citric acid was applied on the exposed root surface for 3 minutes. On the right P4 20ug of human recombinant PDGF-BB dissolved in acetic acid was applied with polypropylene autopipette. On the left P2 and right P2 PDGF-BB was applied after insertion of ${\beta}-Tricalcium$ phosphate(TCP) and collagen (Collatape) respectively. Left mandibular P4 was used as control. Systemic antibiotics (Penicillin-G benzathine and penicillin-G procaine, 1 ml per 10-25 1bs body weight) were administrated intramuscular for 2 weeks after surgery. Irrigation with 0.1% Chlorhexidine Gluconate around operated sites was performed during the whole experimental period except one day immediate after surgery. Soft diets were fed through the whole experiment period. After 2, 4, 8, 12 weeks, the animals were sacrificed by perfusion technique. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. At 2 weeks after surgery, therer were rapid osteogenesis phenomenon on the defected area of the PDGF only treated group and early trabeculation pattern was made with new osteoid tissue produced by activated osteoblast. Bone formation was almost completed to the fornix of furcation by 8 weeks after surgery. New cementum fromation was observed from 2 weeks after surgery, and the thickness was increased until 8 weeks with typical Sharpey’s fibers reembedded into new bone and cementum. In both PDGF-BB with TCP group and PDGF-BB with Collagen group, regeneration process including new bone and new cementum formation and the group especially in the early weeks. It might be thought that the migration of actively proliferating cells was prohibited by the graft materials. In conclusion, platelet-derived growth factor can promote rapid osteogenesis during early stage of periodontal tissue regeneration.

• The korean journal of orthodontics
• /
• v.29 no.5 s.76
• /
• pp.521-534
• /
• 1999

The purpose of this study was to find the difference of stress distribution on canine altered by the application point of preangulated T-loop spring. For this study, the finite element models of upper left canine, upper left second premolar and upper left first molar were made. Also, the finite element models of $0.017{\times}0.025$ inch preangulated, preactivated T-loop spring and $0.018{\times}0.025$ inch stainless steel wire were made. Three types of T-loop spring were made . the middle of activated T-loop is positioned in accordance with the middle position of distance of bracket position of both the canine and first molar, 2mm anterior, 2mm posterior. We compared the forces and the distribution of stress that were generated by the difference of position of T-loop spring. The results were as follows. 1. All of the 3 types of T-loop spring showed the similar retraction forces. 2. All showed the similar amount & pattern of stress distribution. 3. The centers of rotation of canine in 3 types of T-loop spring were same and were positioned between C and D plane. 4. The canine showed the intrusive force by 2mm anterior positioned T-loop spring, but the extrusive force by 2mm posterior positioned T-loop suing. Neverthless, because of the small amount of the forces, the effect of vertical force was not significant.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.2
• /
• pp.260-266
• /
• 2010

Trauma to the primary teeth may have an effect on the successive permanent teeth. Thus, the treatment plans should be focused on safety of their permanent teeth. The degree of developmental disturbances in those permanent teeth depends upon many factors including the age of the children, developmental conditions of the affected teeth, types and severities of trauma and time interval from the moment of trauma to the initial treatment the patients received. The complications of the effected permanent teeth vary from the mild enamel hypoplasia to the premature finishing of teeth development. In this study, children whose ages were 33 months, 5 years, and 26 months presented the developmental disturbances to their permanent teeth, which resulted from the trauma to the primary teeth: the intrusion, the avulsion, and the subluxation. There showed a mild complication in the case of subluxation resulting in enamel hypoplasia, but, the more severe complication of the root dilacerations occurred in the case of intrusion. Furthermore, the 5-year-old patient whose primary dentition was near in transition period to the permanent one, the more complicated problem such as stop of root development of the permanent teeth was resulted from the avulsion. Thus, one should assume that the types of trauma and the age of the children at the moment of trauma have different effects on those successive permanent teeth. In conclusion, when the trauma that causes changes in the position of primary teeth happened, it is important to arrange an appropriate treatment procedure considering the types of trauma and the developmental conditions of the permanent teeth.