• The korean journal of orthodontics
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• v.52 no.2
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• pp.102-111
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• 2022

Objective: To develop and explore the usefulness of an artificial intelligence system for the prediction of the need for dental extractions during orthodontic treatments based on gender, model variables, and cephalometric records. Methods: The gender, model variables, and radiographic records of 214 patients were obtained from an anonymized data bank containing 314 cases treated by two experienced orthodontists. The data were processed using an automated machine learning software (Auto-WEKA) and used to predict the need for extractions. Results: By generating and comparing several prediction models, an accuracy of 93.9% was achieved for determining whether extraction is required or not based on the model and radiographic data. When only model variables were used, an accuracy of 87.4% was attained, whereas a 72.7% accuracy was achieved if only cephalometric information was used. Conclusions: The use of an automated machine learning system allows the generation of orthodontic extraction prediction models. The accuracy of the optimal extraction prediction models increases with the combination of model and cephalometric data for the analytical process.

• Journal of Korean Dental Science
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• v.6 no.2
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• pp.67-77
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• 2013

Purpose: The purpose of this study was to evaluate the survival and success rates of Korean Osstem implants US II Plus, GS II following loading period. Materials and Methods: Dental records were obtained in total 201 patients who were treated with Korean Osstem implants US II Plus, GS II on both maxillary and mandibular anterior and posterior areas in six different clinics for 2 years from January 2007 to December 2008. Total 430 implants were evaluated clinically and radiographically using predefined success criteria prospectively and following results were obtained. Result: US II Plus, GS II implants showed high survival rates of more than 99% and high success rates more than 90% independent of loading period. As a result of cross analysis to evaluate clinical significance between implant loading period and success rate, the P-value of US II Plus was 0.10 (P>0.05), and the P-value of GS II was 0.17 (P>0.05), which showed no statistical significance. Bone quality, smoking, and edentulous state are factors that can affect the survival and success rates following differently loaded implants, but did not significantly affect in this study. Conclusion: These results suggest that selection of loading period of Korean Osstem implants US II Plus, GS II would be done carefully considering implant install area, the quality alveolar bone, the state of edentulous ridge and experience of operator, though they showed clinically good results on both maxillary and mandibular anterior and posterior areas.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.15-26
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• 2009

The purpose of this study was to prepare improved education guideline by grasping parts and items felt difficult to apply instruments by the students of the dental hygiene department in the practice of oral prophylaxis using manikin and analyzing factors influencing the satisfaction at the oral prophylaxis subject. To achieve this purpose, 285 senior students of the dental hygiene department located in the Kwangju. Jeonnam area who took theory and practice courses of oral prophylaxis but only practiced the manikin from the second semester of 1st year were selected as the subjects. The following results were obtained. 1. In the manikin, the most difficult part was maxillary anterior lingual in the use of explorer, sickle scaler, and universal curet, and maxillary right posterior lingual was in the use of gracey curet. In the dentiform, the most difficult item was instrument stroke in the use of explorer, sickle scaler, universal curet and gracey curet. 2. The highest stressor was the lack of knowledge and skill in practice of oral prophylaxis, followed by the lack of confidence, and difference between theory and practice in oral prophylaxis. The overall practice satisfaction was 3.23 at oral prophylaxis. The highest satisfaction was found in patient and operator position(3.51), followed by basic skill(3.34), the way to use hand instrumentation(3.16), and the way to use oral examination instrumentation(3.01). 3. According to school records, satisfaction at oral prophylaxis practice satisfaction was 3.36 of good, 3.24 of fair, and 3.06 of poor, suggesting significant difference(p<0.05). Students who participated just in practice during a school term showed 3.47 of satisfaction. The highest satisfaction was found in a full-time professor as a professor in charge(3.24) and there was significant difference(p<0.05). 4. The highest correlated factor between oral prophylaxis theory and practice satisfaction was curriculum satisfaction. The use of hand instrumentation was found to have the greatest effect on the practice satisfaction at oral prophylaxis, followed by basic skill, the way of basic instrumentation, and position. There was statistically significant difference(p<0.01).

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.673-677
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• 2006

The spectrum of pediatric dentistry has been changing recently, due to many socioeconomic changes and developments in dental materials. The purpose of this study was to recognize the changing pattern in pediatric dental treatment and to present the direction for pediatric dentistry in the future. Patient distribution and practice trends were reviewed based on the patient records of the department of pediatric dentistry, Seoul National University Dental Hospital, from 2000 to 2005. Results were as follows ; 1. In 2000, preventive treatments comprised 14.5%, restorative treatments 52.6%, surgical treatments 11.4% and orthodontic treatments 21.5%. In 2005, the percentages were changed to 12.1%, 38.3%, 13.7%, and 35.9% respectively, showing a decline in preventive and restorative treatments and an increase in surgical and orthodontic treatments. 2. In restorative treatments, the proportion of amalgam, stainless steel crown restoration and pulp treatments decreased, and that of glass ionomer and resin restoration increased. 3. The number of out-patients increased from 2000 to 2002, and decreased thereafter. 4. In 2005, the average age of patients decreased from that of 2000.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.230-237
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• 2013

In this research, the degree of depression and death orientation of the 332 female students majoring in dental hygiene at colleges located in Gyeongsangbuk-do Province were examined and analyzed through a structured self-administered questionnaire from May to July, 2012, for the purpose of improving their mental health. The results are as follows: 1. The degree of depression of the subject students majoring in dental hygiene was shown that 59.9%, 36.8%, 3.0%, and 0.3% of the students were in the normal group, mild depression group, moderate level of depression group, and severe depression group, respectively. 2. The grand mean and the standard deviation of the subjects'death orientation was $2.09{\pm}0.62$ points. 3. The degree of depression of the subjects whose family's economic level was low, whose satisfaction with their family background was low, whose satisfaction level with their major was low, whose school records was low, who frequently thought about death, and who attempted suicide was high in a meaningful way, and death orientation was meaningfully low. In addition, those in the group with the experience of feeling suicidal were proved to have a significantly high degree of depression, and those without the experience of education about death had a low level of death orientation. 4. The degree of depression and death orientation had a positive correlation. When the study results above are combined, follow-up research needs to be conducted so that differentiated programs linked with the care for mental health for the formation of proper attitudes toward depression and death will be established to help students lead a positive life.

• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.381-386
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• 2017

PURPOSE. To integrate extra-oral facial scanning information with CAD/CAM complete dentures to immediately rehabilitate terminal dentition. MATERIALS AND METHODS. Ten patients with terminal dentition scheduled for total extraction and immediate denture placement were recruited for this study. The patients were submitted to a facial scanning procedure using the in-office PritiMirror scanner with bite registration records in-situ. Definitive stone cast models and bite records were subsequently submitted to a lab scanning procedure using the lab scanner (iSeries DWOS; Dental Wings). The scanned models were used to create a virtual teeth setup of a complete denture. Using the intra-oral bite records as a reference, the virtual setup was incorporated in the facial scan thereby facilitating a virtual clinical evaluation (teeth try-in) phase. After applying necessary adjustments, the virtual setup was submitted to a CAM procedure where a 5-axis industrial milling machine (M7 CNC; Darton AG General) was used to fabricate a full-milled PMMA immediate provisional prosthesis. RESULTS. Total extractions were performed, the dentures were immediately inserted, and subjective clinical fit was evaluated. The immediate provisional prostheses were inserted and clinical fit, occlusion/articulation, and esthetics were subjectively assessed; the results were deemed satisfactory. All provisional prostheses remained three months in function with no notable technical complications. CONCLUSION. Ten patients with terminal dentition were treated using a complete digital approach to fabricate complete dentures using CAD/CAM technology. The proposed technique has the potential to accelerate the rehabilitation procedure starting from immediate denture to final implant-supported prosthesis leading to more predictable functional and aesthetics outcomes.

• The Journal of Advanced Prosthodontics
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• v.3 no.4
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• pp.229-235
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• 2011

PURPOSE. The aim of this retrospective study was to evaluate cumulative survival rate (CSR) of Implantium implants followed for 5 years and association between risk factors and the CSR. MATERIALS AND METHODS. A total of two hundred forty-nine Implantium Implants System (Dentium, Seoul, Korea) placed in ninety-five patients from 2004 to 2009 were investigated with several identified risk factors (sex, systemic disease, smoking, alchohol, reason of tooth loss, length, arch (maxilla or mandible), replace tooth type (incisor, canine, premolar or molar) Kennedy classification, prosthodontic type, prosthodontic design, opposite dentition, abutment type, occlusal material, occlusal unit, splint to tooth, cantilever, other surgery). Clinical examination (mobility, percussion, screw loosening, discomfort, etc.) and radiographic examination data were collected from patient records including all problems during follow-up period according to protocols described earlier. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR. RESULTS. Five of 249 implants were failed. Four of these were lost before loading. The 5-year implant cumulative survival rate was 97.37%. Cox regression analysis demonstrated a significant predictive association between overall CSR and systemic disease, smoking, reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The screw related complication was rare. Two abutment screw fractures were found. Another complications of prosthetic components were porcelain fracture, resin facing fracture and denture fracture (n=19). CONCLUSION. The 5-year CSR of Implantium implants was 97.37 %. Implant survival may be dependent upon systemic disease, smoking reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The presence of systemic diseases and combination of other surgical procedures may be associated with increased implant failure.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.4
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• pp.314-321
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• 2014

This study investigated the pattern and treatment of traumatic dental injury (TDI), with respect to the time elapsed prior to the initial visit to the Department of Pediatric Dentistry, Chonnam National University Dental Hospital for TDI, from January 2009 to December 2013. The dental trauma records of a total of 378 patients (940 traumatic teeth) were analyzed. The prevalence rate of dental trauma was twofold higher in males versus females. The principal cause of injury, among all participants, was falling (36.5%). The most commonly affected teeth were the maxillary central incisors (66.9%). Subluxation (43.9%) represented the most common trauma for primary teeth, and uncomplicated crown fracture in permanent teeth (30.9%). Only 10% of patients visited the dental clinic within 1 hour of sustaining trauma. The principal treatment provided for primary teeth, during the initial clinical visit, was follow-up (53.2%); for permanent teeth it was root canal treatment (27.3%). The prevalence of root canal treatment for permanent teeth increased commensurate with the time elapsed since injury. These data suggest that delayed checkup following trauma may increase the risk of loss of pulp vitality.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.230-236
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• 2008

Purpose: This study was performed to investigate the incidence, types of fracture, treatment, associated fracture and complications in patients with nasal bone fracture. Materials and methods: Clinical examination, patient's records and radiographic images were evaluated in 230 cases of nasal bone fractures who were treated at the Department of Oral and Maxillofacial Surgery, Chonnam National University Hospital for recent 5 years; from January 2002 to December 2006. Results: 1. The age of patient was ranged from 4 to 77 years (mean age=36.6 years); Males was 75.7% (n=174), and females 24.3% (n=56). 2. The cause of the nasal bone fracture in this study was a fall or slip down (28.8%, n=66), sports accident (26.0%, n=60), fighting (21.3%, n=49), traffic accident (9.6%, n=22), industrial trauma (7.8%, n=18), and the others (6.6%, n=15). 3. For the patterns of fracture, simple fracture without displacement occured in 10.4% (n=24). Simple fracture with displacement without septal bone fracture was found in 49.5% (n=114). Simple fracture with displacement in company with septal bone fracture showed in 32.6% (n=75). Commiuted fracture with severe depression was presented in 7.4% (n=17). 4. The reduction the displaced nasal bone was carried out in 2 to 10 days (mean 6.8 days) after the injury. 5. Nasal bone fracture associated with Le Fort I fracture (6.5%, n=6.5), Le Fort II fracture (7.4%, n=17), Le Fort III fracture (1.3%, n=3), NOE fracture (13.9%, n=32), ZMC fracture (17.4%, 40), maxillary bone fracture (8.3%, n=19), orbital blow-out fracture (15.7%, n=36), frontal bone fracture (1.3%, n=3) and alveolar bone fracture (10.9%, n=25). 6. The major type of treatment method was closed reduction in 90% (n=207), open reduction in 3% (n=7), and observation in 7% (n=16). 7. There were some complications such as ecchymosis, hyposmia, hypo esthesia and residual nasal deformity which are compatible. Open rhino-plasty was conducted for 3 patients who had residual nasal deformity. Conclusions: These results suggest that most of nasal bone fractures are occurred physically active aged groups(age 10-49 years) and could be treated successfully with closed reduction at 7 days after the injury.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.5
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• pp.303-308
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• 2022

Objectives: Selection of treatment methods for mandibular condylar fractures remains controversial. In this study, we investigated treatment methods for condylar fractures to determine the indications for open or closed reduction. Patients and Methods: Patients >12 years of age treated for mandibular condylar fractures with a follow-up period of ≥3 months were included in this study. The medical records of enrolled patients were reviewed for sex, age, fracture site, treatment method (open or closed reconstruction), postoperative intermaxillary fixation period, operation time, and complications. Radiological analysis of fracture fragment displacement and changes in ramal height difference was performed using computed tomography and panoramic radiography. Results: A total of 198 patients was investigated, 48.0% (n=95) of whom underwent closed reduction and 52.0% (n=103) underwent open reduction. There was no significant correlation between reduction method and patient sex, age, or follow-up period. No statistically significant difference between the incidence of complications and treatment method was observed. None of the patients underwent open reduction of condylar head fracture. Binary logistic regression analysis showed that open reduction was significantly more frequent in patients with subcondylar fracture compared to in those with a fracture in the condylar head area. There was no statistically significant correlation between the groups and fracture fragment displacement. However, there was a significant difference between the treatment groups in amount of change in ramal height difference between the fractured and the non-fractured sides during treatment. Conclusion: No significant clinical differences were found between the open and closed reduction methods in patients with mandibular condylar fractures. According to fracture site, closed reduction was preferred for condyle head fractures. There was no significant relationship between fracture fragment displacement and treatment method.