• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.4
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• pp.279-288
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• 2007

In the present study, we focused on stem cells in the dental papilla of the tooth germ. The tooth germ, sometimes called the tooth bud, is the primordial structure from which a tooth is formed. The tooth germ consists of the enamel organ, the dental papilla, and the dental follicle. The dental papilla lies below a cellular aggregation of the enamel organ. Mesenchymal cells within the dental papilla are responsible for formation of dentin and pulp of a tooth. Tooth germ disappears as a tooth is formed, but that of a third molar stays in the jawbone of a human until the age of 10 to 16, because third molars grow slowly. Impacted third molar tooth germs from young adults are sometimes extracted for orthodontic treatment. In the present study, we evaluated the osteogenic activity and mineralization of cultured human dental papilla-derived cells. Dental papillas were harvested from mandible during surgical extraction of lower impacted third molar from 3 patients aged 13-15 years. After passage 3, the dental papilla-derived cells were trypsinized and subsequently suspended in the osteogenic induction DMEM medium supplemented with 10% fetal bovine serum, 50 g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate at a density of $1\;{\times}10^6\;cells/dish$ in a 100-mm culture dish. The dental papilla-derived cells were then cultured for 6 weeks and the medium was changes every 3 days during the incubation period. Dental papilla-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 7 of culture period, then decreased in intensity during the culture period. ALP mRNA level was largely elevated at 1 weeks and gradually decreased with culture time. Osteocalcin mRNA expression appeared at day 14 in culture, after that its expression continuously increased in a time-dependent manner up to day 28. The expression remained constant thereafter. Runx2 expression appeared at day 7 with no detection thereafter. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. Osteocalcin secretion was detectable in the culture medium from 1 week. The secretion of osteocalcin from dental papilla-derived cells into the medium greatly increased after 3 weeks although it showed a shallow increase by then. In conclusion, our study showed that cultured human dental papilla-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.2
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• pp.191-193
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• 2008

Impacted third molars of the mandible are generally found at or close to the second molar. If the third molar is impacted far distant from its original site, it may be affected by cysts or tumors. Ectopic impaction of third molar in the condyle area is very rare. Furthermore, impaction without cystic lesion is even less common. The etiology of migration of the mandibular third molar without cystic lesion is unknown. So periodical X-ray taking is essential.

• Journal of The Korean Dental Society of Anesthesiology
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• v.11 no.1
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• pp.32-37
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• 2011

Pulsus paradoxus has been defined as a decrease in systolic blood pressure (SBP) of 10 mmHg or more during inspiration. This report describes pulsus paradoxus detected by pulse oximetry during dental procedure. Case: A 10 years old boy who had impacted mandibular premolar with malformation scheduled for extraction under intravenous sedation with Fentanyl and Propofol. The patient showed upper airway obstruction with stridor and pulsus paradoxus. Though pulsus paradoxus is generally critical condition, in this case, respiration and other vital sign was maintained comparatively well with care in administering oxygen and considerate monitoring of pulse oximetry and capnography. Discussion: Noninvasive continuous monitoring of pulse oximetry allows recognition of pulsus paradoxus which can lead to serious problems. Clinicians should know very well about it and be able to manage of this kind of situation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.255-264
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• 1993

The purpose of this study was to obtain some informations for the radiographic differential diagnosis between dentigerous cysts and unicystic ameloblastomas in the mandible. The authors observed and compared the clinico-radiographic features of 38 cases of dentigerous cyst and 32 cases of unicystic ameloblastoma associated with impacted mandibular molar. The obtained results were as follows: Dentigerous cysts occurred the most frequently in the 3rd decade, but unicystic ameloblastomas in the 2nd decade, and both lesions occurred with slight predilection in males. Average of lesional size of unicystic ameloblastomas was larger than that of dentigerous cysts, and lesions of over 25㎠ were only in unicystic ameloblastomas. Cortical thinning and expansion were more frequently observed in unicystic ameloblastomas at 72.9% than in dentigerous cysts at 15.8%. Dentigerous cysts showed smooth border at 89.5%, but unicystic ameloblastomas showed smooth border at 53.1% and scalloped border at 46.9%. Dentigerous cysts showed well-defined outline at 81.6%, but unicystic ameloblastomas showed well-defined outline at 53.1% and moderate-defined outline at 46.9%. In both lesions, the mandibular 3rd molar was the most frequent causative tooth. Average of distance between the cemento-enamel junction and lesional wall attachment of the causative tooth was longer in unicystic ameloblastomas than in dentigerous cysts. Severe displacement of causative tooth was more frequent in unicystic ameloblastomas at 62.5% than in dentigerous cysts at 23.7%. Dentigerous cysts showed homogeneous lesional radiolucency at 89.5%, but unicystic ameloblastomas showed inhomogeneous lesional radiolucency at 53.1%. Root resorption of adjacent tooth and displacement of mandibular canal were more frequent in unicystic ameloblastomas at 65.2% and 61.5% than in dentigerous cysts at 15.8% and 38.1% respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.166-173
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• 2012

Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth. Dilacerations are estimated to occur in 3% of all permanent dentitions. However, the etiology of dilaceration is not yet fully understood. Traumatic injury to the deciduous predecessors and ectopic development of the tooth germ are the two commonly cited causes of this anomaly. The involved tooth is usually the maxillary central incisor and it also shows high prevalence of impaction. At first, We tried to do surgical exposure with orthodontic traction but to no avail. After then surgical repositioning of the dilacerated tooth was performed. Finally, Satisfactory results were obtained at the end of treatment, with improvement in dental esthetics and functional aspects.

• The korean journal of orthodontics
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• v.41 no.5
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• pp.346-353
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• 2011

Objective: The purpose of this study was to investigate the prevalence of dental anomalies in outpatient clinics. Methods: The subjects of this study were 3,133 patients who visited the clinic between January 2009 and June 2011. The dental records and panoramic films of the patients and detection of supernumerary, missing, and impacted teeth, transposition, and peg lateralis were reviewed. The results were analyzed according to gender and types and locations of dental anomalies. Results: Among the patients, 362 had dental anomalies, with a prevalence rate of 11.55%. Congenital missing teeth (5.71%) ranked first in the categories, and impacted teeth (3.09%) ranked second. The percentage of patients having supernumerary teeth, peg lateralis, and dislocated teeth were 1.79%, 1.66%, and 0.45%, respectively. Conclusions: Congenital missing teeth and impacted teeth are, respectively, the first and second most common dental anomalies in Korean dental patients.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.3
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• pp.217-226
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• 2022

Background: Intraosseous anesthesia is the process by which an anesthetic solution, after penetration of the cortical bone, is directly injected into the spongiosa of the alveolar bone supporting the tooth. This study aimed to compare the effectiveness of the traditional inferior alveolar nerve block (IANB) and computerized intraosseous anesthesia in the surgical extraction of impacted lower third molars, compare their side effects systemically by monitoring heart rate, and assess patients' a posteriori preference of one technique over the other. Methods: Thirty-nine patients with bilaterally impacted third molars participated in this study. Each patient in the sample was both a case and control, where the conventional technique was randomly assigned to one side (group 1) and the alternative method to the contralateral side (group 2). Results: The traditional technique was faster in execution than anesthesia delivered via electronic syringe, which took 3 min to be administered. However, it was necessary to wait for an average of 6 ± 4 min from the execution to achieve the onset of IANB, while the latency of intraosseous anesthesia was zero. Vincent's sign and lingual nerve anesthesia occurred in 100% of cases in group 1. In group 2, Vincent's sign was recorded in 13% of cases and lingual anesthesia in four cases. The average duration of the perceived anesthetic effect was 192 ± 68 min in group 1 and 127 ± 75 min in group 2 (P < 0.001). The difference between the heart rate of group 1 and group 2 was statistically significant. During infiltration in group 1, heartbeat frequency increased by 5 ± 13 beats per minute, while in group 2, it increased by 22 ± 10 beats per minute (P < 0.001). No postoperative complications were reported for either technique. Patients showed a preference of 67% for the alternative technique and 20% for the traditional, and 13% of patients were indifferent. Conclusion: The results identified intraosseous anesthesia as a valid alternative to conventional anesthesia in impacted lower third molar extraction.

• Journal of The Korean Dental Society of Anesthesiology
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• v.9 no.1
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• pp.24-29
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• 2009

When performing the inferior alveolar nerve block anesthesia, surgeon often faced a difficulty of the surgical operation due to the incomplete anesthesia. One of the reason is the variety of mandibular canal anatomy. Up to now, there are some reports of index cases about bifid mandibular canal among mandibular canal anatomic variation, and some classification is applied according to anatomical location and configuration. When surgical operation is performed involving mandible such as dantal implant treatment, extraction of an impacted third molar, sagittal split ramus osteotomy, etc, the position of mandibular canal should be considered. Bifid mandibular canal clinically causes troublesome cases of anesthesia when inferior alvelor nerve block, especially is performed extraction of an impacted third molar. Therefore, It is important for clinicians to recognize the presence of bifid canals on radiographys. Nowadays, the position of mandibular canal can be measured precisely by using Dental CT. It is not found by panorama image but is found by Dental CT sometimes. Among the patients, which take panorama and Dental CT simultaneously, for tooth extraction of lower impacted third molar in our department, we report the case that did not identifying in panorama but identifying it in Dental CT.

• Archives of Craniofacial Surgery
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• v.20 no.6
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• pp.376-381
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• 2019

Background: This study was conducted to determine the relationship between third molar (M3) and mandibular fracture. Methods: Patients with unilateral mandibular angle or condyle fractures between 2008 and 2018 were evaluated retrospectively. Medical records were reviewed regarding the location of fractures, and panoramic radiographs were reviewed to discern the presence and position of ipsilateral mandibular third molars (M3). We measured the bony area of the mandibular angle (area A) and the bony area occupied by the M3 (area B) to calculate the true mandibular angle bony area ratio (area A-B/area A×100). Results: The study consisted of 129 patients, of which 60 (46.5%) had angle fractures and 69 (53.5%) had condyle fractures. The risk of angle fracture was higher in the presence of M3 (odds ratio [OR], 2.2; p< 0.05) and the risk of condyle fracture was lower in the presence of M3 (OR, 0.45; p< 0.05), than in the absence of M3. The risk of angle fracture was higher in the presence of an impacted M3 (OR, 0.3; p< 0.001) and the risk of condyle fracture was lower in the presence of an impacted M3 (OR, 3.32; p< 0.001), than in the presence of a fully erupted M3. True mandibular angle bony area ratio was significantly lower in the angle fractures than in the condyle fractures (p= 0.003). Conclusion: Angle fractures had significantly lower true mandibular angle bony area ratios than condyle fractures. True mandibular angle bony area ratio, a simple and inexpensive method, could be an option to predict the mandibular fracture patterns.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.435-440
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• 2011

Maxillary canine impaction is a common eruption problem in children. Impaction frequently involves further complications such as root resorption of adjacent teeth, cyst formation and migration of the neighboring teeth, etc. Various treatment modalities include extraction of preceding deciduous canine, orthodontic traction, and surgical extraction followed by immediate replantation of the extracted tooth at the proper position(autotransplantation). Autotransplantation is considered as the treatment of choice when surgical exposure and subsequent orthodontic traction are difficult or impossible due to unfavorable impacted position. The prognosis of autotransplantation is affected by the degree of apex formation, surgical procedures performed, timing of root canal treatment, and length of stabilization period. In these two cases presented, the patients with unerupted maxillary canine were treated with autotransplantation. One case was thought that guidance of eruption by orthodontic traction was difficult because of its unfavorable impacted position. In the other case, parents didn't agree to treat by orthodontic traction, therefore autotransplantation was done. In both cases, autotransplantation was carried out following root canal treatment and orthodontic treatment, and both cases have demonstrated to be successful to this day.