• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권5호
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• pp.438-443
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• 2004

Objectives : The proper development of the facial structures relies upon a sequence of tightly regulated signaling interactions between the ectoderm and mesoderm involving the participation of several families of signaling molecules. Among these, bone morphogenetic proteins (BMPs) have been suggested to be a key signal that regulates the development of the mandible and the initiation and morphogenesis of the teeth. The aim of this study was to examine the artificial development of the mandibular structures and to examine the role of BMPs on tooth morphogenesis and differentiation using an organ culture system. Materials and Methods : The tooth germs from Ed 11.5, 13.5 mice were dissected, and transplanted into the diastema of the mandible primordia. The mandibles containing the transplanted tooth germs were cultured in vitro. During this period, beads soaked with BMP4 were implanted around the transplanted tooth germs. In addition, a diastema block containing the transplanted tooth germ was dissected, then transferred to an adult mouse kidney. After the organ culture, the developing mandibular explant was removed from the kidney and prepared for the tissue specimens. Odontogeneis of the transplanted tooth germs was examined after Hematoxylin-eosin, Masson-trichrome staining. Results : Proliferation and differentiation of the tooth germs cultured in the diastema was observed. In the BMP4-treated tooth germs, the formation of the first and second molars was noted. The crown of the developing tooth showed the formation of a mature cusp with the deposition of enamel and dentin matrix. In conclusion, it was confirmed that BMP4 is involved in the formation of a dental crown and the differentiation of ameloblasts and odontoblasts of the molar tooth during the development of the transplanted tooth germs.

• 대한치과교정학회지
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• 제35권6호
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• pp.485-494
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• 2005

상악 측절치와 견치의 치근 사이에 식립한 microimplant를 이용하여 상악 전치의 합임과 설측으로의 치근 이동을 얻을 수가 있었으며, 상악 견치와 제1소구치의 치근 사이에 식립한 microimplant를 이용하여 과맹출된 상악 견치를 함입시켰다. 또한 상악 제1, 2대구치의 치근 사이에 식립한 microplant를 이용하여 상악 견치 및 구치의 후방 이동 및 상악 전치의 후방 견인을 시행하였다. Anterior bite plane과 intrusion arch, 그리고 II급 고무 등과 같은 전통적인 방법을 사용하여 하악 전치의 합입 및 구치부의 정출을 얻을 수가 있었으며, 과개 교합 및 상악 전치의 설측 경사가 해소 되면서 하악골이 전방으로 약간 이동하였다. 이와 같이, MIA는 II급 2류 부정교합환자에 있어서 II급 견치 및 구치 관계 그리고 과개 교합을 동시에 해소 하는데 절대적인 고정원을 제공하였다.

• 대한치과교정학회지
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• 제50권4호
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• pp.229-237
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• 2020

Objective: To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods: The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years' experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results: The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950-0.992 and 0.965-0.993; 0.976-0.994 and 0.973-0.995 in the maxillary and mandibular arches, respectively). Conclusions: The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

• Journal of Korean Dental Science
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• 제7권2호
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• pp.94-98
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• 2014

Numerous oral and maxillofacial surgeons have found facial space infections after tooth extraction. Most of these infections can be managed easily, but some of them could be life-threatening. Among the facial infections, temporal space infections are rare. Most temporal space infections could be observed as secondary to maxillary third molar infections, maxillary sinusitis, and maxillary sinus fractures. Note, however, that there are insufficient studies on temporal space abscess due to mandibular second molars, especially with acupuncture. A 74-year-old female came to our hospital with severe trismus and facial swelling on the right temporal, buccal, posterior auricular, and cervical regions. The patient had undergone extraction of tooth #47 secondary to dental caries by a general dentist about a month ago. After the dental procedure, the patient had been treated with acupuncture therapy around the right temporomandibular joint area at the oriental medicine clinic. We performed emergency incision and drainage under general anesthesia and started antibiotic treatment with IV ampicillin/sulbactam 3 g every 24 hours and vancomycin 1 g every 24 hours for 5 days. The patient's symptoms subsided and ultimately disappeared. Temporal space abscess after mandibular molar extraction is quite rare. In this case, the spreading mechanism against gravity is considered to be acupuncture therapy.

• 대한소아치과학회지
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• 제44권2호
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• pp.210-219
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• 2017

본 연구는 영구치열이 완성된 청소년을 대상으로, MIH를 포함한 영구치 법랑질 저광화의 유병률과 분포를 조사하고, 심미적 만족도와의 연관성을 파악할 목적으로 시도되었다. 양산시 거주 14 - 16세 청소년 1371명을 대상으로 횡단연구가 수행되었다. MIH를 포함한 법랑질 저광화는 유럽소아치과학회 기준에 의거하여 평가하였다. 전치부 심미성에 대한 설문 조사를 병행하여 전치부 법랑질 저광화의 연관성을 분석하였다. MIH에 이환된 경우는 189명으로 13.8%의 유병률을 보였다. 모든 영구치 중 1개 이상에서 저광화 병소가 나타난 경우는 318명(23.2%)으로 일반적인 MIH 기준 적용시에 비해 매우 높게 나타났다. 영구치에 나타난 법랑질 저광화 이환 빈도는 하악 제1대구치, 상악 중절치, 하악 제2대구치 순이였다. 전치부에 대한 평가에서는 상악 중절치의 절단연이 가장 높은 이환 빈도를 보였다. 전치부에서 저광화 병소가 존재하는 경우 높은 심미치료 요구도가 관찰되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권3호
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• pp.301-309
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• 2000

This clinical study was made of 214 cases of the jaw cysts which were diagnosed histopathologically in the Department of Oral and Maxillofacial Surgery, Wonkwang University Dental Hospital from Jan. 1, 1991 to Dec. 31, 1998. Medical records, radiographs, histopathological reports of 214 cases with jaw cysts were retrospectively reviewed. The results were as follows : 1. Among the total patient of 214 cases, male were 143 cases, and female are 71 cases, male predominated by the ratio of 2.04. 2. The periapical cysts and the dentigerous cyst are the most common cyst, irrespective of 116 cases(54.2%) and 58 cases(27.1%). 3. The periapical cyst has no gender prediction, male were 70 cases and female were 54 cases, the mean ages were 39.3 years(SD=18.4). The most common involving teeth were maxillary anterior teeth(59.7%). 4. The dentigerous cyst predominantly occurred in third decade (18 cases : 31%), and the mean ages were 31.9 years(SD=14.8). Dentigerous cysts predominantly occurred in male by the ratio of 7.29 (male : 51 cases, female : 7 cases). Maxillary anterior teeth(43.1%) and mandibular molars(32.8%) were most frequently involved. 5. The odontogenic keratocyst predominantly occurred in second and third decade and mean ages were 23.5 years(SD=17.2). The mandibular molars(60%) were most frequently involved. 6. All nasopalatine cyst occurred after fourth decade, mean ages were 49.5years(SD=10.4). In the gender incidence of nasopalatine cyst, 1 case occurred in female and 10 cases occurred in male. 7. In the surgical intervention of jaw cyst, cyst enucleation and marsupialization performed in 156 cases. Cyst enucleation with bone graft performed in 58 cases and iliac autogenous bone grafts most frequently performed in 29cases. 8. The diameter range of cyst enucleation with bone graft were from 15mm to 120mm with a cyst diameter of 33.3mm. (SD=15.2) The diameter range of cyst enucleation and marsupialization were from 7mm to 82mm with a cyst diameter of 20.4mm.(SD=9.0) The diameter of cyst enucleation with bone graft were significantly greater than diameter of cyst enucleation. (p<0.05) 9. Post-operative complications occurred in 9 cases(15.5%) in which cyst enucleation with bone grafts performed and occurred in 31 cases(19.9%) in which cyst enucleation.

• 대한치과의사협회지
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• 제48권2호
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• pp.140-145
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• 2010

True vertical root fracture (VRF) in nonendodontically treated teeth confined to the root surface (fatigue root fracture; FRF) is apparently uncommon, the few documented reports being Chinese. The aim of this study is to analyze the cases of a fatigue root fracture and to find out the characteristic features of teeth with a FRF. A total of 21 consecutive cases of fatigue root fracture occurring in 16 patients were reviewed. In terms of the occlusion, the presence of restorations, the location, the age and gender, each tooth and patient were analyzed. The prevalent age was in those over 50 years of age (75%) and FRFs were more frequent in male patients (69%). Fatigue root fractures occurred most frequently in the mandibular molars (61.9%; 42.9% in first molar, 19% in second molar). Fatigue root fractures were observed most frequently in the teeth with no restorations (85.7%) and in the patients with occlusal problems (94%). FRFs seem to occur frequently and may represent an undiagnosed clinical entity deserving of our attention.

• 대한치과의사협회지
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• 제40권7호통권398호
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• pp.542-547
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• 2002

This study was aimed to help diagnose the vertical root fractures in endodontically and in nonendodontically treated teeth. This was a study about mine teeth with a vertical root fractures. Four cases were nonendodontically treated teeth and five cases were endodontically treated teeth. A collection of information including past dental history, periodontal probing, and X-ray was gathered on each case. One of the endodontic cases had no periodontal pocket depth and was in acute pain. It was confusing to find whether causes were because of endodontic failure or vertical root fractures. Most of the vertical root fractures were found in patients aged between 50 and 60. Vertical root fractures were found in the molar and premolar of maxillary and mandibular teeth. The second molars repecially, which had C shaped roots had vertical root fractures with apical propagation type. The apical propagation type means that vertical root fracture initiates in root apex and propagate to coronal root. The teeth with vertical root fractures of the apical propagation type, which was in acute pain, were very difficult in differential diagnosis of periodontal lesion and endodontic failure. Therefore, the dental history was very important to make a differential diagnosis. Past pain history repeated uncomfortable symptoms in bite was a key of differential diagnosis.

• 대한소아치과학회지
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• 제51권1호
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• pp.22-31
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• 2024

The objective of this study was to assess the wear resistance of tooth-colored materials used in crown restoration for primary molars with a chewing simulator. In this study, four groups-three experimental groups and one control group-were included. They consisted of three-dimensional (3D) printed resin crowns (NextDent and Graphy), milled nano-hybrid ceramic crowns (MAZIC Duro), and prefabricated zirconia crowns (NuSmile). Twelve mandibular second molar specimens were prepared from each group. In the wear experiment, 6.0 × 10⁵ cycles were conducted with a force of 50 N, and a 6 mm-diameter steatite ball was used as an antagonist. The amount of wear was calculated by comparing the scan files before and after the chewing simulation using 3D metrology software, and the worn cross-section was confirmed by scanning electron microscopy (SEM). The resin and ceramic groups did not exhibit any statistically significant differences. However, compared to other crown groups, the zirconia crown group demonstrated notably reduced levels of wear (p < 0.05). In SEM images, layers and cracks were observed in the 3D-printed resin crown groups, which differed from those in the other groups.

• 구강회복응용과학지
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• 제20권2호
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• pp.71-81
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• 2004

The purpose of this study was to compare the distributing pattern of stress on the finite element models of two units implant prosthesis with one angulated placement of two implant fixtures. The two unit implant crowns simulated to mandibular first and second molars were made. The two kinds of finite element models were designed according to angulation of fixture ($4.0mm{\times}11.5mm$) : Model 1($15^{\circ}$ buccally angulated placement of one fixture on second molar area), Model 2($15^{\circ}$ lingually angulated placement of one fixture on second molar area). Axial loads of 200N were applied to the center of central fossa and to distance of 2mm and 4mm apart from the center of central fossa. Von-Mises stresses were recorded and compared in the fixtures, and buccolingual section of implants. The results were as follows: 1. Under axial loading at the central fossa, the stress was distributed along the straight fixture except apical portion, while on buccally or lingually angulated placement, the highest stresses were concentrated in the neck portion on the opposite side of the angulated fixture. 2. With offset distance increasing, the stresses were concentrated greater in buccal neck of lingually angulated fixture than in lingual neck of buccally angulated fixture. From the above results, in designing of the occlusal scheme for implant prosthesis with the angulated fixture, occlusal contacts should be placed to distribute stress axially in maximum intercuspation and to avoid offset force during eccentric movements.