• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.535-539
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• 2000

Ectopic eruption of a tooth into the oral environment occurs commonly whereas ectopic eruption of a tooth into other sites is rare. Those that have been reported include the nasal cavity, chin, mandibular condyles, coronoid processes, orbits and maxillary sinus. The etiologic factors of ectopic eruption are developmental disturbances such as cleft palate and teeth displaced by trauma or cysts, maxillary infection, genetic factors, crowding and exceptionally dense bone. In many cases, however, the etiology cannot be identified. Eruption of the teeth into the maxillary sinus is uncommon, however the identification of such teeth can be important since they have the potential to cause considerable morbidity. The definitive treatment is surgical removal of the teeth. A 7 year-old-boy visited the Department of Pediatric Dentistry, College of Dentistry, Yonsei University for treatment of dental caries. The abnormal erupting paths of the left and right maxillary canines were found during routine panoramic radiographic investigations. A panoramic radiograph taken at 13 years old revealed that two maxillary canines were located into the sinus. The teeth were extracted by the Caldwell-Luc approach.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.334-347
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• 2006

The aim of this study is to evaluate the reasonableness of the medical fee on oral and maxillofacial surgery field according to surgeon's opinions and actual conditions. The medical fee has significant influence on hospital income, the supply and distribution of medical manpower, quality and facilities of medical services. Questionnaire survey was sent to 86 oral and maxillofacial surgeons who worked more than 3 years in general hospital. Among them, 25 doctors replied the 109 answers survey and the average of treatment time and physician work relative value on each category was calculated. And the health insurance cost (that has been applied since 2003) was compared with the questionnaire results. And finally we investigated items that health insurance system did not include in oral and maxillofacial field but actually performed in oral and maxillofacial surgery clinic. The result was that the medical fee did not properly reflect physician work relative value of actual treatments. In case of complicated extraction, work relative value needed 3.5 times enhancement of present value. For simple impacted tooth extraction 1.8 times, for impacted tooth extraction including odontomy 1.7 times, and for fully impacted tooth more than 2/3 of it located into the alveolar bone, 1.8 times enhancement needed. In respect of the present physician work relative value, hemimandibulectomy with neck lymph node dissection for the malignancy is appropriated as 3.3 times of open reduction and internal fixation for the mandibular fracture, but the questionnaire result showed 25 times discrepancy. In conclusion, this research shows the need for intervention that health insurance included items and legal relative medical value must act in union with treatment in clinic to reduce the imbalance between them.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.221-227
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• 2020

In the case of complete edentulous patients, as the mandibular alveolar bone absorption progresses, the maintenance and stability of the existing dentures, which had satisfactory functions in the past, are deteriorated. Despite of the need to fabricate new dentures, they often hesitate due to physical burdens on the duration and intensity of future treatment progress due to the effects of aging and systemic diseases. In the case of these completely edentulous patients, it is necessary to consider the treatment goals that can reduce the number of visits and the adaptation period for new dentures before starting the treatment. This case is a case of producing complete dentures of elderly patients with deteriorated physical ability. In addition to producing suction dentures through preliminary and definitive closed mouth functional impression suggested by Sato, CAD / CAM technique was used to transfer occlusal functional information of existing dentures to facilitate adaptation to new dentures.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.4
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• pp.244-252
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• 2019

Proper positioning of maxillary incisors is key to success of surgery combined treatment. Establishing surgery plan would be a difficult job if maxillary incisors are lost. Patient who lost all of her maxillary incisors due to accident came for orthodontic treatment. Through careful modification of maxillary archform, pre-surgical orthodontic treatment was conducted with four prosthetic space consolidation. Position of incisors was decided by help of 3D prosthetic set-up, and 1-jaw surgery was planned. After relative short treatment period of 28 months, final prosthesis was done. When alveolar bone loss happens, harmonious prosthesis of upper incisors is difficult. Utilizing mandibular set-back surgery and incisor positioning using 3D set-up could make a better environment for treatment outcome. Strategic pre-surgical orthodontic treatment can allow shorter time and less number of prosthetics.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.32.1-32.4
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• 2020

Background: Le Fort I osteotomy is a highly effective treatment for skeletal jaw deformities and is commonly performed. High Le Fort I osteotomy is a modified surgical procedure performed for improving the depression of the cheeks by setting the osteotomy higher than the conventional Le Fort I osteotomy. Developments in three-dimensional (3D) technology have popularized the use of 3D printers in various institutions, especially in orthognathic surgeries. In this study, we report a safe and inexpensive method of performing a high Le Fort I osteotomy using a novel 3D device and piezosurgery, which prevent tooth root injury without disturbing the operation field for patients with a short midface and long tooth roots. Results: A 17-year-old woman presented with facial asymmetry, mandibular protrusion, a short midface, and long tooth roots. We planned high Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. Prevention of damage to the roots of the teeth and the infraorbital nerve and accurate determination of the posterior osteotomy line were crucial for clinical success. Le Fort I osteotomy using 3D devices has been reported previously but were particularly large in size for this case. Additionally, setting the fixing screw of the device was difficult, because of the risk of damage to the roots of the teeth. Therefore, a different surgical technique, other than the conventional Le Fort I osteotomy and 3D device, was required. The left and right parts of the 3D device were fabricated separately, to prevent any interference in the surgical field. Further, the 3D device was designed to accurately cover the bone surface from the piriform aperture to the infra-zygomatic crest with two fixation points (the anterior nasal spine and the piriform aperture), which ensured stabilization of the 3D device. The device is thin and does not interfere with the surgical field. Safe and accurate surgical performance is possible using this device and piezosurgery. The roots of the teeth and the infraorbital nerve were unharmed during the surgery. Conclusions: This device is considerably smaller than conventional devices and is a simple, low-cost, and efficient method for performing accurate high Le Fort I osteotomy.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.324-330
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• 2018

In order to produce a stable denture for severe alveolar bone loss area, it is not only important that .0a suitable occlusion is established but also to consider compatibility with the surrounding muscle to form a suitable polished surfaces. Neutral zone is defined as a potential area where the neuromuscular system of the tongue, cheeks and lips is balanced can be determined through the neutral zone impression technique. And if artificial teeth are aligned within the neutral zone and the polished surface follows the anatomical form of the dynamic muscle, higher stability and retention of the denture may be obtained through coordination with the surrounding muscle tissue. This case is being reported since the concept of the neutral zone was applied to a patient with severely atrophic residual alveolar ridge and the result was clinically satisfactory in both function and aesthetics.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.367-378
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• 2023

With the recent development of computer-aided design-computer-aided manufacturing technology and 3D printing technology, and the introduction of various digital techniques, the accuracy and efficiency of top-down definitive prosthetic restoration are increasing. In this clinical case, stable occlusion support was obtained through the placement of a total of 9 maxillary and mandibular posterior implants in patient with anterior-posterior crossed occlusion. The edentulous area of the maxillary anterior teeth, which showed a tendency of high resorption of the residual alveolar bone, was restored with a Kennedy Class IV implant assisted removable partial denture to restore soft tissue esthetics. Computed tomography guided surgery was used to place implants in the planned position, double scan technique was used to reflect the stabilized occlusion in the interim restoration stage to the definitive prostheses, and metal 3D printing was used to manufacture the coping and framework. This clinical case reports that efficient and predictable top-down full mouth rehabilitation was achieved using various digital technologies and techniques.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.197-207
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• 1999

Although there is a severe underlying skeletal deformity, the dentition has often maintained some occlusal contact and interdigitation by the teeth compensating in their positions for the skeletal problem, and these dental compensations are manifested in all three planes of space. The purposes of present investigation were 1) to study the pattern of dentoalveolar compensation of hyperdivergent skeletal pattern , and 2) to compare the dentoalveolar compensations of hyperdivergent skeletal pattern in children with adults. The samples selected for this study were consisted of 60 subjects in normal group, 60 subjects in hyperdivergent group. Each was divided into two subgroups by age ; child groups($8\~12yr$ old) and adult groups(17yr old over). The findings of this study were as follows; 1. In child, hyperdivergent subjects had smaller posterior lower facial height(p<0.01) and slightly longer anterior lower facial height than normal ones. In adults, they still expressed smaller posterior lower facial height and much longer anterior lower facial height than normal ones(p<0.01). 2. Hyperdivergent subjects had larger amount of upper and lower incisor relative eruption to their basal bone length than normal ones(p<0.05). In adult, relative eruption of upper incisor was increasing(p<0.05), although relative eruption of lower incisor remained the same as the child. 3. In child, there was no difference between hyperdivergent group and nomal one in the upper and lower molar relative eruption to their basal bone length. In adult, hyperdivergent group had target amount of upper molar relative eruption than normal ones(p<0.01), but relative eruption of lower molar was similar to normal ones. 4. Hyperdivergent group had larger angle between lower occlusal plane and mandibular plane than normal group(p<0.01). Upper occlusal plane of adult groups rotated more antero-superiorly than child groups, and adult hyperdivergent group had sleeper upper occlusal plane than normal group(p<0.05).

• 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 Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.10-20
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• 2012

Purpose: The purpose of this study was to investigate the stress distribution in mandibular implant-supported overdentures and tooth-supported overdentures with telescopic crowns. Materials and methods: The assumption of this study was that there were 2, 3, 4 natural teeth and implants which are located in the second premolar and canine regions in various distributed conditions. The mandible, teeth (or implants and abutments), and connectors are modeled, and analyzed with the commercial software, ANSYS Version 10.1. Stress distribution was evaluated under 150 N vertical load bilaterally on 3 experimental conditions - between canine areas, canine and $2^{nd}$ premolars, 10 mm posterior to $2^{nd}$ premolars. Results: Overall, the case of the implant group showed more stress than the case of the teeth group in stress distribution to bone. In stress distribution to superstructures of tooth and implants, there was no significant difference between TH group and IM group and the highest stress appeared in TH-IV and IM-IV. The stress caused from bar was much higher than those of implant and tooth. TH group showed less stress than IM group in stress distribution to abutment teeth and implant. Conclusion: The results shows that it is crucial to make sure that distance between impact loading point and abutment tooth does not get too far apart, and if it does, it is at best to set abutment tooth on premolar tooth region. It will be necessary to conduct more experiments on effects on implants, natural teeth and bone, in order to apply these results to a clinical treatment.