• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.373-389
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• 1997

The purpose of this stdudy was to evaluate the effect of maxillary protraction and the relapse of hard and soft tissue after maxillary protraction. For this study 29 patients who were treated with maxillary protractor and labiolingual archwire were selected. Their mean age was 9 years 4 months and mean treatment period was 8.5 months. Lateral cephalograms were taken at pretreatment, immediately after treatment and one to three months after removal of the maxillary protractor. They were traced on skeletodental and soft tissue structures based on Burstone's analysis and analyzed by Quick-Ceph Image Digitizing System(ORTHODONTIC PROCESSING). The mean and standard deviation between pretreatment and posttreatment and between posttreatment and retention period for each cephalometric variable were calculated. Student t-test was used to determine the statistical significance of the changes in each variable. Correlation coefficients between hard tissue and soft tissue were used to determine interrelationship. The results were as follows. 1. After maxillayy protraction, the maxilla and maxillary dentition moved antero-inferiorly, the mandibld and mandibular dentition moved postero-interiorly and palatal plane rotated antero-superiorly by $0.59^{\circ}$. 2. After maxillary protraction, the soft tissue of upper lip moved antero-interiorly with the movement of hard tissue but the antero-posterior position of lower lip was stable in spite of the change of hard tissue. The thickness of upper lip was decreased and that of lower lip was increased after maxillary Protraction. 3. During the retention period, the position of jaws was relatively stable but upper and lower anterior teeth and antero-superiorly rotated palatal plane relapsed to original position. 4. During the retention period, the soft tissue of lips was stable antero-posteriorly and moved mote inferiorly than posttreatment. 5. The correlation coefficients between the postion of upper and lower incisal edge and that position of lips were high, especially in horizontal change.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.202-213
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• 2008

Objective: The purpose of this study was to compare the cephalometric measurements of obese and non-obese Korean male patients with obstructive sleep apnea syndrome (OSA). Methods: Eighty-seven adults who had visited the Sleep Disorder Clinic Center in Keimyung University, Daegu, Korea were examined and evaluated with polysomnography (PSG) and lateral cephalogram. They were divided into 4 groups (non-obese simple snorers, obese simple snorers, non-obese OSA patients, obese OSA patients) according to AHI (Apnea-Hypopnea Index) and BMI (Body Mass Index). Results: The obese OSA group had the highest AHI among the 4 groups. The non-obese OSA group had a significantly steeper mandibular angle and shorter tongue length than the obese OSA group. The hyoid bone of the obese OSA group was positioned anterior and inferior as compared with the non-obese OSA group. Multiple regression analysis showed that tongue length in the obese OSA group and retroposition of hyoid bone in the non-obese OSA group were significant determinants for the severity of AHI. Conclusions: From a cephalometric point of view, the obese and non-obese pateints with OSA may be characterized by different pathogeneses. Therefore, they have to be managed by individualized treatment. For the obese OSA patients, weight control must be advised as a first choice and for the non-obese OSA patients, oral appliance, nasal CPAP, UPPP and others could be chosen according to the obstructive sites.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.475-484
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• 2005

This study was performed to investigate the reproducibility of the horizontal and midsagittal planes, and to suggest a stable coordinate system for three-dimensional (3D) cephalometric analysis. Eighteen CT scans were taken and the coordinate system was established using 7 reference points marked by a volume model, with no more than 4 points on the same plane. The 3D landmarks were selected on V works (Cybermed Inc., Seoul, Korea), then exported to V surgery (Cybermed Inc., Seoul, Korea) to calculate the coordinate values. All the landmarks were taken twice with a lapse of 2 weeks. The horizontal and midsagittal planes were constructed and its reproducibility was evaluated. There was no significant difference in the reproducibility of the horizontal reference planes, But, FH planes were more reproducible than other horizontal planes. FH planes showed no difference between the planes constructed with 3 out of 4 points. The angle of intersection made by 2 FH planes, composed of both Po and one Or showed less than $1^{\circ}$ difference. This was identical when 2 FH planes were composed of both Or and one Po. But, the latter cases showed a significantly smaller error. The reproducibility of the midsagittal plane was reliable with an error range of 0.61 to $1.93^{\circ}$ except for 5 establishments (FMS-Nc, Na-Rh, Na-ANS, Rh-ANS, and FR-PNS). The 3D coordinate system may be constructed with 3 planes; the horizontal plane constructed by both Po and right Or; the midsagittal plane perpendicular to the horizontal plane, including the midpoint of the Foramen Spinosum and Nc; and the coronal plane perpendicular to the horizontal and midsagittal planes, including point clinoidale, or sella, or PNS.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.275-282
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• 2008

Objective: The purpose of this study was to investigate the effect of using laser for ceramic bracket bonding of porcelain surfaces and to compare it with conventional treatment of porcelain surfaces. Methods: Ninety feldspathic porcelain specimens were divided into 9 groups of 10, with each group having different surface treatments performed. Surface treatment groups were orthophosphoric acid, orthophosphoric acid with silane, hydrofluoric acid, hydrofluoric acid with silane, sandblasted, sandblasted with silane, laser etched, laser etched with silane, and glazed surface served as a control group. In the laser etched groups, the specimens were irradiated with 2-watt superpulse carbon dioxide ($CO_2$) laser for 20 seconds. Ceramic brackets were bonded with light-cure composite resin and all specimens were stored in water at $37^{\circ}C$ for 24 hours. Shear bond strength was determined in megapascals (MPa) by shear test at 1 mm/minute crosshead speed and the failure pattern was assessed. For statistical analysis, one-way ANOVA and tukey test were used. Results: Statistical analysis showed significant differences between the groups. The HFA + S group showed the highest mean shear bond strength ($13.92{\pm}1.94\;MPa$). This was followed by SB + S ($10.16\;{\pm}\;1.27\;MPa$), HFA ($10.09\;{\pm}\;1.07\;MPa$), L + S ($8.25\;{\pm}\;1.24\;MPa$), L ($7.86\;{\pm}\;0.96\;MPa$), OFA + S ($7.22\;{\pm}\;1.09\;MPa$), SB ($3.41\;{\pm}\;0.37\;MPa$), OFA ($2.81\;{\pm}\;0.37\;MPa$), G ($2.46\;{\pm}\;1.36\;MPa$), Bond failure patterns of HFA and silane groups, except L + S, were cohesive modes in porcelain while adhesive failure was observed in the control group and the rest of the groups. Conclusions : A 2-watt superpulse $CO_2$ laser etching of porcelain surfaces can provide a satisfactory result for porcelain surface treatment for ceramic bracket bonding. Laser irradiation may be an alternative conditioning method for the treatment of porcelain surfaces.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.459-473
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• 2004

Recently, many children have been treated under sedation in the department of pediatric dentistry of the dental hospital of Kangnung National University, and sedation cases are increasing gradually. So, in this study. the author analyzed and studied about the characteristics of sedated pediatric dental patients and their parents with patient chart and questionnaire at first visit, from 1999 to 2002 for the purpose of making pediatric dental treatment plan more effective and the improvement of behavior management for better pediatric dentistry. The results were follows : 1. The number of total pediatric and sedative patients increased from 1999 to 2002. 2. The sedated pediatric dental patients were younger than total pediatric dental patients(p<0.001). 3. In visit frequency per month, the sedated patients showed higher percentage on March, July, November contrast to non-sedated patients(p<0.001). 4. In parental occupation, there was a significant difference between sedated patients and non-sedated patients(p<0.001). 5. Caries treatment rather than preventive care or orthodontic treatment, was primarily composed of chief complaint of sedated patients(p<0.001). 6. The sedated patients showed worse response to previous treatment than non-sedated patients, and their parents also expected worse response contrast to non-sedated patients (p>0.001). 7. The patients who were introduced, occupied 31.2% of sedated pediatric dental patients and referral by the dentist were composed of the highest percentage(58.3%). 8. In case of uncooperative child at conventional behavior management, the parents of sedated pediatric dental patients prefered to sedation(50.9%). while the parents of non-sedated patients prefered to physical restraint(54.6%) (p<0.001).

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.345-354
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• 2001

The purpose of this study was to make public oral health plan more effective and the improvement of the hospital management system for better clinical dental practice. Distribution and trends were examined in all patients who had been examined and diagnosed at Department of Pedodontics, Dental Hospital, Chosun University over 10 year-period from 1990 to 1999 Results were as follows, 1. The number of patients per year was increasing trend after 1996 and higher visiting rate in male(55.9%) than in female(44.1%). 2. Age distribution had shown $3\sim4$ year-old cup being the largest (23.4%) and each percentage of $5\sim6,\;7\sim8,\;0\sim2,\;9\sim10,\;11\sim12,\;13\sim14,\;above\sim15$ year-old group was 19.9%, 17.7%, 14.6%, 12.6%, 8.0%, 3.3%. 0.5%. 3. Geographic distribution showed a majority of patients in Kwang-Ju (83.0%). Group in the suburbs of Kwang-Ju(Jang-Sung group) was 5.4%. 4. Dental caries showed the highest percentage(40.5%) in chief complaints and percentage of oral exam, orthodontic problem, oral pain, trauma, supernumerary teeth, swelling was 13.9% 12.6%, 8.8%, 7.4%, 5.5%, 4.9%. 5. In all patients with traumatic problem, crown fracture showed the highest percentage(41.4%) and percentage of subluxation was 19.4%. 6. Majority(78.7%) of patients were not refered, and percentage of patients refered from local clinic was 20.5%. 7. Patients who had periodic check-up comprised 19.6%, and percentage of after 3, 6, 9, 12, 18, 24month was 36.7%, 22.2%, 13.5%, 11.3%, 5.4%, 11.0%.

• Journal of dental hygiene science
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• v.12 no.6
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• pp.558-565
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• 2012

The purpose of this study was to work related musculoskeletal disorders are a major. Occupational disease of the dental care profession is no exception. The survey was self-reported questionars of 300 dental hygienists that 268 dental hygienists reply to self-reported survey. This study results are as follows: Subjects of research analyzing the degree of physical musculoskeletal disorders pain, shoulder 90.3%, neck 89.2%, leg 83.6%, 81.7% back, hand/wrist/fingers 75.7%, arm/elbow, according to 52.8%. Therefore the work province of the research object people the musculoskeletal disorders appeared different. Generally characteristic was taller dental hygienists lower back pain and were out of less weight, study subjects had neck and arm pain. 29~33 year-old age the shoulder, over the age of 34 the arm/elbow to be high (p<0.05). Working environment to become a career, the more hand/wrist/fingers and the pain increased (p<0.05). The neck, shoulders (p<0.05), arm (p<0.01), waist high in the 3~4 years experience. And leg/foot was in the 1~2 years experience. This increase in working hours had increased pain in the neck but the hand/wrist/finger pain in the small hours of experience in the high pain(p<0.01). Conclusion of the musculoskeletal disorders of the dental hygienists often than the average for this risk is recognized. When it occurs early in treatment can be simple, but time is left to revert to normal when you do not already. Therefore, maintaining proper posture and dental hygienists, pain or fatigue appeared to accumulate immediately treated continued efforts are needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.245-253
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• 2018

This study investigated 2,088 economically active workers aged 20 to 65 years selected from the sixth Korea National Health and Nutrition Examination Survey to evaluate the relationship between chronic diseases and oral health behaviors among economic workers and examine the risk factors for oral diseases. The results of the study were as follows. Dental caries were related to subjective oral health status, toothache experience, orthodontic treatment experience, chewing problems, speaking problems, oral examination, and dental clinic use. Periodontal disease was associated with oral health status, toothache experience, orthodontic experience, and chewing and speaking problems. The risk factors for chronic diseases and oral health behavior were as follows. Hypertension, 1.37 times; obesity, 1.48 times; diabetes, 1.5 times; low HDL-cholesterol, 1.31 times; hepatitis A antibody, 1.53 times higher. Health status was found to be 1.70 times higher in dental caries and 2.10 times higher in periodontal disease. The tooth experience was 1.30 times higher in dental caries and 1.35 times higher in periodontal disease. Problems chewing were 1.76 times for dental caries and 1.78 times for periodontal disease. The possibility of dental caries and periodontal disease was 1.44 times higher. Smokers were 1.61 times more likely to have dental caries and 1.63 times more likely to have periodontal disease. These results suggest that periodontal diseases increase the risk of chronic diseases and oral health behavior increases the risk of dental caries and periodontal disease. Although dental caries seem to have a lower risk of becoming a chronic disease if only oral health care is good, it is considered that both chronic disease and oral health care are important for periodontal disease.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.39-44
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• 2008

The treatment of esthetic areas with single-tooth implants represents a new challenge for the clinician. In 1993, a modification of the forced eruption technique, called "orthodontic extrusive remodelling," was proposed as a way to augment both soft- and hard-tissue profiles at potential implant sites. This case report describes augmentation of the coronal soft and hard tissues around a fractured maxillary lateral incisor associated with alveolar bone loss, which was achieved by forced orthodontic extrusion before implant placement. Through these procedures we could reconstruct esthetics and function in a hopeless tooth diagnosed with subgingival root fracture by trauma.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.693-702
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• 2005

Accurate timing and sequence of eruption of permanent teeth are indicies of growth and essential for pediatric dentistry and pediatric clinical orthodontics. From the children brought to the Yonsei Dental Hospital during 2001 to 2003, 654 boys and 542 girls, ranging in age from five to fourteen years, were selected and analysed. The following was concluded. 1. Eruption time of maxillary teeth is 6.81 years in boys, 6.78 years in girls for central incisor, 8.30 years in boys, 7.98 years in girls for lateral incisor, 10.28 years in boys, 10.04 years in girls for canine, 9.74 years in boys, 9.90 years in girls for first premolar, 10.87 years in boys, 10.41 years in girls for second premolar, 6.25 years in boys, 6.54 years in girls for first permanent molar, 12.21 years in boys, 12.03 years in girls for second permanent molar 2. Eruption time of mandibular teeth is 6.00 years in boys, 6.06 years in girls for central incisor, 6.99 years in boys, 6.74 years in girls for lateral incisor, 9.83 years in boys, 9.17 years in girls for canine, 9.92 years in boys, 9.75 years in girls for first premolar, 10.66 years in boys, 10.39 years in girls for second premolar, 5.99 years in boys, 5.75 years in girls for first permanent molar, 11.92 years in boys, 12.17 years in girls or second permanent molar. 3. The following eruption sequence was observed the first permanent molar erupted first, followed by the central incisor, the lateral incisor, the first premolar, the canine, the second premolar and the second permanent molar in the maxilla. The first permanent molar erupted first, followed by the central incisor, the lateral incisor, the canine, the first premolar, the second premolar and the second permanent molar in the mandible.