• 대한치과보철학회지
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• 제31권3호
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• pp.394-410
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• 1993

This study was accomplished for appreciation of the mandibular moments according to antero- posterior movement of pivot placed on the lower natural dentition. For this study, 20 subjects(male, $21\sim30$ yrs., average age 24) in the category of normal occlusion were selected, and the intraoral Vitallium clutches were cast and fabricated for each subjects. A 2-dimension PSD(Position Sensitive Detector, Hamamatsu Photonics Co., Japan) was attached to maxillary clutch in a mode of three dimensional control and LED (Light Emit Diode, Hamamatsu Photonics Co., Japan) was set up on mandibular clutch. Both clutches were set into oral cavity of each subjects and adjusted. Then the subjects were allowed to intercuspated with maximal bite force while the pivoting ball in the mid-line moving from anterior toward posterior position. The displacement scales were recorded by CCD camera(Sony, CCD-TR-705) and VCR, The conclusions were as follows : 1. When the subject was allowed to bite the metal pivoting ball in the midline of lower dentition with maximal bite force voluntarily while moving from lower central incisor to canine, 1st premolar, End premolar, 1st molar and 2nd molar. The lever actions on the pivot were revealed in all subjects. The equilibrium of moment were revealed on the pivots of 1st premolar(14 subjects), End premolar(4 subjects), and canine(2 subjects) areas. 2. The changes of loading on the TMJ according to antero-posterior positional changes of metal pivoting ball were able to recognize as follow. Compression on the TMJ was increased when the pivot moves anteriorly from the equilibrium point, and tension on the TMJ was increased when posteriorly. 3. 13 subjects were recognized their habitual chewing sides(Rights, Left8), and 7 subjects were not. During maximal biting, mandible was displaced toward their habitual chewing sides on the metal pivoting ball in the frontal plane. 4. In cephalometric analysis, the average genial angle of 20 subjects was $116.75^{\circ}$ and the average mandibular body length was 79.77mm. The equilibrium points of mandibular moment were positioned more posteriorly in the subjects having larger Genial angle than in the smaller(p<0.05). Relationships among the angle between FH plane and occlusal plane, the angle between occlusal plane and mandibular plane , and mandibular body length were not significant(p>0.05).

• Journal of Periodontal and Implant Science
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• 제28권4호
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• pp.785-797
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• 1998

This study has been done to prove that keratinized gingiva is required for the periodontal health and to analyse the adequate width that is necessary. Until now, the study on frenum has been documented on changing its location. But the location or the formation of the frenum has not been reported. This experiment has used 173 patients from the department of periodontology of Dankook University to investigate the width of keratinized gingiva, the formation of the frenum and its location for the frequency. This study also looks into the relationship between the gingival recession and the structure of the frenum, and affects they have on periodontal health. The width of the keratinized gingiva in the mandible has been found to be highest in the lateral incisor than in the central incisor. The width decreased from the canine to the first premolar until it reached the molar. The interproximal area of the mandibular frenum was 77.9%, which was greater than the frequency (22.1%) from the midline of the teeth. The highest frequency of frenum was at 30.6% in between the both central incisor then second greatest at 20.6% in between the right canine and the right first premolar. Frenum was not found in between the second premolar and the distal area. In the morphology of the frenum, it was found that 43.4% out of 551 parts were found to be a single narrow frenum, and the double or triple ligamented form of the complex frenum were found in similar frequency of 237 parts, but the broad frenum was rarely frequent. The incisal area was popular mostly with the single narrow frenum, the left premolar area frequented 57.4%, and the right premolar frequented 64.7%. Because the distance between the frenum apex and the gingival margin measured to be about 5mm or greater, the frenum apex started in the mucogingival junction and not just below the keratinized gingiva. In the 551 area investigated, 48.3% of gingiva showed recession, incisal area had recession the least at 44.9%, right buccal side at 47.4%, and right buccal side frequented the highest at 52.1%. The teeth that showed recession recessed at the average of 2.151.0.mm and the left canine showed the greatest amount of gingival recession. In the investigation to find out if the keratinized gingiva and the gingiva recession had mutually related somehow, the width of keratinized gingiva showed no affect on the probing depth, but had affected in the gingiva recession. This investigation showed that the gingival recession and the morphology of the frenum related in that, the single narrow frenum had recessed the least and the broad frenum recessed the most. With this analysis, a conclusion was drawn that the morphology of the frenum had affected in the gingical recession.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권4호
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• pp.350-359
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• 2005

Sagittal split ramus osteotomy(SSRO) has been commonly performed in the mandibular prognathism. The previous studies of the mandibular anatomy for SSRO have mostly been used in dry skull without consideration of age, sex or jaw relationship of patients. This study was performed to evaluate the location of mandibular canal and the anatomy of ramus, such as the location of mandibular lingula and the ramal bone marrow, which were associated with SSRO procedures, in the patients with mandibular prognathism and normal young adults by using computerized tomographs(CT) and 3D images. The young adults at their twenties, who were considered to complete their skeletal growth, and seen in the Department of Orthodontics and Oral and Maxillofacial Surgery in Chonnam National University Hospital between March 2000 and May 2003, were selected. This study was performed in 30 patients (15men, 15women) who were diagnosed as skeletal class I normal relationship, and another 30 patients (15men, 15women) who were diagnosed as skeletal class III relationship upon clinical examination and lateral cephalometric radiographs. The patients were divided into 2 groups : Class I group, the patients who had skeletal class Ⅰ normal relationship(n=30, 15men, 15women), and Class III group, the patients who had skeletal class III relationship(n=30, 15men, 15women). Facial CT was taken in all patients, and pure 3D mandibular model was constructed by V-works version 4.0. The occlusal plane was designed by three points, such as the mesiobuccal cusp of both mandibular 1st molar and the incisal edge of the right mandibular central incisor, and used as a reference plane. Distances between the tip of mandibular lingula and the occlusal plane, the sigmoid notch, the anterior and the posterior borders of ramus were measured. The height of ramal bone marrow from the occlusal plane and the distance between mid-point of mandibular canal and the buccal or lingual cortex of the mandible in the 1st and 2nd molars were measured by V-works version 4.0. Distance(Li-OP) between the occlusal plane and the tip of mandibular lingula of Class III Group was longer than that of Class I Group in men(p<0.01), but there was no significant difference in women between both groups. Distance(Li-SN) between the sigmoid notch and the tip of mandibular ligula of Class III group was longer than that of Class I Group in men(p<0.05), but there was no significant difference in women between both groups. Distance(Li-RA) between the anterior border of ramus and the tip of mandibular lingula of Class III Group was shorter than that of Class I Group in men and women(p<0.01). Distance(Li-RP) between the posterior border of ramus and the tip of mandibular lingula of Class III Group was slightly shorter than that of Class I Group in men(p<0.05), but there was no significant difference in women between both groups. Distance(RA-RP) between the anterior and the posterior borders of ramus of Class III Group was shorter than that of Class I Group in men and women(p<0.01). Longer the distance(SN-AN) between the sigmoid notch and the antegonial notch was, longer the vertical ramal length above occlusal plane, higher the location of mandibular lingula, and shorter the antero-posterior ramal length were observed(p<0.01). Height of ramal bone marrow of Class III Group was higher than that of Class I Group in men and women(p<0.01). Distance between mandibular canal and buccal cortex of Class III Group in 1st and 2nd lower molars was shorter than that of Class I Group in men and women (p<0.05 in 1st lower molar in men, p<0.01 in others). These results indicate that there are some anatomical differences between the normal occlusal patients and the mandibular prognathic patients, such as the anterior-posterior length of ramus, the height of ramal bone marrow, and the location of mandibular canal.

• 대한소아치과학회지
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• 제45권4호
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• pp.464-473
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• 2018

2011년 7월부터 2016년 6월까지 서울대학교 치과병원에 맹출 장애를 주소로 내원한 703명의 환자를 대상으로 897개의 치아에 대하여 맹출 장애의 빈도, 원인, 치료방법, 교정적 견인방법, 견인기간 등을 조사하여 다음과 같은 결론을 얻었다. 맹출 장애는 상악 견치, 상악 중절치, 상악 제1대구치에서 가장 높은 빈도로 발견되었다. 상악 견치의 맹출장애는 여자에게서 호발 하였고(p < 0.001), 상악 중절치(p = 0.009)와 상악 제1대구치(p < 0.001), 하악 제1대구치(p = 0.028)의 맹출 장애는 남자에게서 호발 하였다. 맹출 장애의 원인은 맹출 경로의 이상, 맹출 경로 상에 장애물의 존재가 가장 많았다. 치료 방법으로는 교정적 견인이 가장 많이 시행되었으며, 상악 중절치에서 가장 높은 빈도로 시행되었다. 교정적 견인 기간은 연령이 어릴수록(p < 0.001), 치관의 위치가 낮을수록(p < 0.001), 견인기간이 짧게 관찰되었다. 소아 환자는 정기적인 검진을 통해 맹출 장애를 조기에 발견하는 것이 중요하며, 정확한 진단과 치료계획으로 적절한 시기에 치료를 시작하는 것이 필요하다.

• 대한치과의사협회지
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• 제56권5호
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• pp.263-276
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• 2018

Long-term survival and prognosis of narrow-diameter implants have been reported to be adequate to consider them a safe method for treating a deficient alveolar ridge. The objective of this study was to perform case report of narrow-diameter implants with a trapezoid-shape in anterior teeth alveolar bone. A 50-year-old male patient presented with discomfort due to mobility of all of the maxillary teeth and mandibular incisors. Due to destruction of alveolar bone, four anterior mandibular teeth were extracted. Soft tissue healing was allowed for approximately 3 months after the extraction, and a new design of implant placement was planned for the mandibular incisor area, followed by clinical and radiological evaluation. Implant placement was determined using an R2GATE surgical stent. The stability of the implants was assessed by ISQ measurements at the first and second implant surgery and after prosthetic placement. At 1 and 3 months and 1 year after implantation of the prosthesis, clinical and radiological examinations were performed. Another 50-year-old male patient presented with discomfort due to mobility of the mandibular central incisors. For the same reason as in the first patient, implant placement was carried out in the same way after extraction. ISQ measurements and clinical and radiological examinations were performed as in the previous case. In these two clinical cases, 12 months of follow-up revealed that the implant remained stable without inflammation or additional bone loss, and there was no discomfort to the patient. In conclusion, computer-guided implant surgery was used to place an implant in an optimal position considering the upper prosthesis. A new design of a narrow-diameter implant with a trapezoid-shape into anterior mandibular alveolar bone is a less invasive treatment method and is based on the contour of the deficient alveolar ridge. Through all of these procedures, we were able to reduce the number of traumas during surgery, reduce the operation time and total treatment period, and provide patients with more comfortable treatment.

• 대한치과보철학회지
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• 제36권2호
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• pp.245-257
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• 1998

This study was performed to measure the changes of the mandibular movement and the masticatory muscular activities - anterior temporal and masseter muscle of both side - reflected by intentional increase of anterior guidance angie. For this study, 5 volunteers (3 males and 2 females with average age of 24.0) were selected. Each volunteer had Angle's classification I and did not have any missing tooth except third molar and any extensive restorations. Metallic guide plate was made at volunteer's working model fabricated by improved dental stone and cemented to the palatal surface of maxillary central incisor using resin cement(Panavia $21^{(R)}$) and then adjusted not to give any occlusal interferences at intercuspal position. The activity of masticatory muscles and the changes of mandibular movement were recorded by EMG and Sirognathograph in Biopak analysing system(Bioresearch Inc., Milwaukee, Wisconsin, USA). Measurement was done at before experiment, immediatley after placement, 1 week after placement, immediately after removal, and 1 week after removal. The results were as follows: 1. Moderate phonetic disturbance and mild headache were occured to 3 volunteers for 2 days after setting and 1 volunteer had positive reaction to percussion and slight midline diastema. But all of these clinical signs were diappeared 1 week after removal and the other volunteer did not have any special clinical sign. 2. In the EMG of the mandibular rest position, the mean value of anterior tempotal muscle was increased immediately after placement(p<0.01) and then decreased 1 week after placement(p<0.05) and increased 1 week after removal(p<0.05) but not recovered as before experiment. The mean value of masseter muscle was decreased during the experiment period. 3. In the EMG during mandibular protrusive movement, all muscular activity was decreased during the experiment period. Reduced activity was not recovered 1 week after removal(p<0.03). 4. During the habitual opening, anteroposterior movement of mandible was decreased immediately after placement(p<0.05) and then increased 1 week after placement but not statistically significant(p>0.1). Vertical movement was not shown significant difference during the experiment period(p>0.1). Lateral movement was decreased immediately after placement(p<0.05) and then increased 1 week after placement but not recovered as before experiment. The opening and closing velocity of mandible was shown minor changes but not statistically significant. 5. During the habitual opening, anteroposterior movement of mandible was decreased 1 week after placement(p<0.05) and then increased immediately after removal and recovered 1 week after removal as before experiment. Vertical movement was not shown significant changes. Lateral displacement of mandible was increased continuously and recovered 1 week after removal. Opening velocity was temporarily increased immediately after removal but recovered and closing velocity was not shown significant changes. 6. During the right side chewing, anteroposterior movement of mandible was increased immediately after removal but recovered and vertical movement was not shown statistically significant results. Lateral displacement and velocity of mandible were not shown significant results. 7. During the left side chewing, the changes of mandibular movement pattern were not shown statistically significant results.

• 대한소아치과학회지
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• 제35권2호
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• pp.313-318
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• 2008

치내치(dens invaginatus)는 형태분화기에 비정상적인 치아발생이 원인으로 경조직이 석회화되기 전에 법랑질 상피가 함입되어 생기는 드문 치아 기형이다. 치내치의 발생 빈도는 0.04-10 %이고 대부분이 상악에서 발생하며 특히 상악측절치에서의 빈도가 높고 하악에서는 드물게 발생한다고 보고되었다. 치내치는 우상치나 왜소치, 쌍생치, 과잉치, 상아질 형성부전증과 같은 형태 이상과 연관되어서 나타나는 경우도 있다. 치내치는 함입된 정도에 따라 3가지로 분류할 수 있고 다양한 해부학적 변이를 보이며, 이러한 기형은 미생물의 침입을 용이하게 하므로 치아우식증과 치수감염 및 괴사의 위험성을 높인다. 치수조직에 문제가 생긴 경우 근관의 복잡한 해부학적 형태 때문에 근관치료가 매우 어려우므로 조기에 진단하여 치료하는 것이 중요하다. 본 증례들은 하악 중절치에 드물게 발생하는 치내치를 가진 환아에 대한 것으로 하악 중절치에서의 치내치 유병율과 치료에 대한 고찰을 하였기에 이를 보고하는 바이다.

• 한국치위생학회지
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• 제10권4호
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• pp.655-661
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• 2010

Objectives : This study is aimed to prevent the damage to the inferior alveolar nerve during the orthognathic surgery. Methods : The control group consist of 50 patients with class I occlusion. The experimental group consist of 50 patients with class III malocclusion. The cepalometric radiography was used to evaluate the position of the mental foramina. Results : In the first, mental foramen position of class III was more inferior 0.85 mm in the distance between base of mandible and mental foramen. But the distance between occlusal plan and mental foramen had not statistically significant. Secondly, mental foramen location of Mandibular Prognathism was more anterior 0.91 mm in the distance between coronal plane of mandible included pogonion point and mental foramen. Also, the distance of occlusal-coronal plane of mandible included central incisor and mental foramen had statistically significant. The mental foramen location of class III was more anterior 4.81 mm than class I patients. Conclusions : The result of this study could help the clinicians to apprehend fundamental data with various facial skeletal types for any related researches about the location of the mental foramina for other purposes.

• Journal of Periodontal and Implant Science
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• 제43권5호
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• pp.243-247
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• 2013

Purpose: The aim of this work is to evaluate a surgical technique for mobilization of mal posed dental implant in anterior area. Methods: A 38-year-old patient consulted our unit for esthetic dissatisfaction with the implant treatment of a central incisor. An implant was observed in 11 and 21, where 11 was 3 mm above the ideal limit, with excessive vestibular angulation. The choice was made to perform a segmental osteotomy and mobilize the bone block and the implant down and forward; a bone block extracted from the mandibular ramus was installed between the implant block and the bed to stabilize the segment. Results: After 4 months, a conventional fixed prosthesis was created and the esthetic result achieved was close to what the patient wanted, with no need for further surgery. The surgical condition was stabilized and maintained for the long-time and no complications how necrosis, infection or bone defects was present. Conclusions: It was concluded that the procedure is efficient, and the biological arguments in favor of the procedure are discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권6호
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• pp.575-580
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• 2005

Transitional implants were developed to support provisional restorations and to allow for load-free osseointegration of conventional implants while a patient was provided with immediate esthetics and function and are usually placed simultaneously at the time of definitive implant placement. Transitional implants are placed in a non-submerged fashion in a single-stage surgery and are designed to be immediately loaded. They generally are made of commercially pure titanium or titanium alloy and are designed as 1-piece implants composed of root and crown replacement segments. Transitional implants can be used in a wide range of indications, such as basic use as temporary implant, to support and protect the primary implants during the healing phase, single crown in the edentulous anterior region of mandibular, anchorage for orthodontic treatment, support a surgical and radiographic template, and primary implant to extremely atrophied alveolar crests of the mandible and maxilla. This article describes the clinical use of transitional implants to support the provisional complete denture and single crown in the restricted edenturous central incisor region of mandible.