• Journal of Oral Medicine and Pain
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• v.37 no.4
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• pp.205-211
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• 2012

A 35 year-old female presented with the complaint of sudden occurrence of bite change and concurrent opening limitation, as well as pain in the right temporomandibular joint (TMJ) during mouth opening. From her history it was revealed that she had simple clicking of right TMJ for several years before onset of these symptoms, and that the clicking sound subsided recently after development of opening limitation. On clinical examination, anterior open bite, midline shift of the mandible to right, and premature contacts on left posterior teeth were observed. Maximum mouth opening and lateral movement to left were also restricted. On magnetic resonance images, the right TMJ showed anterior disc displacement without reduction and the posterior joint space is greatly collapsed by retrusion of the condyle. It was thought that the sudden occurrence of occlusal change would be resulted from abrupt displacement of the mandible associated with development of the anterior disc displacement without reduction. The stabilization appliance traction therapy was performed initially for first 3 months along with physical and pharmacologic therapy. However, the anterior open bite and opening limitation didn't resolve and the position of mandible still remained altered. So the stabilization appliance was changed to intermaxillary traction device. Then the mandible returned progressively to normal position and the occlusion became more stable and comfortable. After 5 months of intermaxillary traction therapy, the anterior open bite was dissolved completely and the occlusion became stabilized satisfactorily along with recovery of normal mouth opening range. On post-treatment magnetic resonance image, remodeling of condylar head was observed.

• Korean Journal of Cleft Lip And Palate
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• v.6 no.1
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• pp.1-15
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• 2003

Cleft lip and palate deformity have unknown patterns of maxillofacial growth and development. The maxillofacial growth can be affected either by congenital or environmental factors such as infection and trauma. Surgical repair of cleft lip and palate may interfere the subsequent growth and development of maxillofacial region. The purpose of this study is to evaluate the characteristics of development of maxillofacial region in adult cleft lip and palate patients and to compare post-treat-ment craniofacial morphology between cleft lip and palate patients with secondary alveolar bone graft group and normal group. The material for this study consisted of 20 adult male patients with cleft lip and palate(mean 22.5, range 18-31) visited in Yeungnam University medical center. Cephalometric tracing and measurements were done by one investigator. Results were followed: The values of Na. perpendicular to point A, SNA angle and Pogonion to Na. perpendicualrwere -4.93±5.70, 76.45±4.69, and -6.38±6.73. The values of effective maxillary length, effective mandibular length, mandibular plane angle and facial axis angle were 85.6±4. 42, 123.88±7.10, 29.9±5.09 and 5.53±2.03. The value of upper incisors to point A was 3.95±2.74.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.264-274
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• 2016

It is a trend that carbonated drink intake among adolescents is increasing, which makes young people more vulnerable to dental erosion. However, in Korea, public knowledge about dental erosion is very insufficient. The aim of this study was to investigate the prevalence of dental erosion and to assess its risk indicators among 13-15 years old students in Yangsan, Korea. A total of 1,371 adolescents were examined by one calibrated clinician. Dental erosion was assessed by using the Visual Erosion Dental Examination system. Correlation between their dietary habit, oral hygiene and dental erosion was assessed. The data showed that 676 (49.3%) adolescents had dental erosion. The prevalence of dental erosion was significantly higher in females than in males. The prevalence of tooth erosion in mandible is higher than in maxilla. Dental erosion was generalized to develop mostly on anterior teeth, especially lateral incisor, however, the severity score was highest in canines. Following questionnaire analysis, dental erosion was significantly associated with milk and flavored milk. No other associations were detected. The prevalence of dental erosion in this study is higher than those of previous reports. On the contrary to previously reported studies, the prevalence of dental erosion in females is higher than in males.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.679-684
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• 2007

Odontoma is the most common benign odontogenic tumors, and have been defined as mixed odontogenic tumor composed of epithelial and mesenchymal cells. Odontoma is believed to be hamartomatous rather than neoplastic in nature. The classification by WHO divides odontoma into 2 groups such as complex odontoma and compound odontoma. Compound odontoma comprises dental tissues, resembling the morphology of a tooth and has predilection for the anterior maxilla. In contrast, complex odontoma has unorganized mass, not resembling the normal tooth and has predilection for the posterior mandible. Odontoma is almost asymptomatic, so it is usually found on routine radiographic examination. Common presenting symptom is impacted or unerupted permanent teeth and retained primary teeth, but coexistent odontoma and congenital missing of permanent teeth is a very rare condition. The recommended treatment for an odontoma is conservative surgical excision, with care taken to remove the surrounding soft tissue. This report presents 2 patients with compound odontoma of the mandible who have congenital missing of the permanent teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.281-295
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• 1994

It is very important for the ideal restorations of anterior openbite patients to record the mandibular movement and to harmonize mandibular movement with other organs in stomatognathic systems. This study was designed to compare the mandibular movement of anterior openbite patients with that of normal bite(Angle Class I) patients, to ascertain which components of mandibular movement have differences between two groups, and to use for occlusal treatment of mandibular movement. Saphon Visi-trainer Model 3(Tokyo Shizaisha Co. Japan) and Denar Pantronic(Denar Corp.,U.S.A.) were used to record mandibular movement. Pantronic survey was peformed by using an arbitrary hinge axis according to manufacturer's direction. Twenty-eight adult who have physiologically normal occlusion(Angle Class I) and are free of TM dysfunction were selected as a control group(Group 1). Fifteen adult who are anterior openbite patient and have not anterior guidance function and have posterior interference at protrusion were selected as a experimental group(Group 2). The results are as follows : 1. There was no statistically significant difference between the average immediate and progressive side shift of anterior openbite patients(0.54mm, $7.57^{\circ}$) and those of normal group(0.49mm, $5.96^{\circ}$). 2. The average protrusive and orbiting condylar inclination of anterior openbite patient$(30.87^{\circ},\;32.27^{\circ})$ were significantly lower than those of normal group$(36.11^{\circ},\;39.04^{\circ})$ (P<0.05). 3. In the results of Visi-trainer recordings, the mean for the maximum protrusion, the maximum laterotrusion, the angle of laterotrusion and the angle of protrusion in the horizontal trajectory between group 1 and 2 did not differ significantly. 4. The mean for the angle of protrusion, the maximum opening in the frontal trajectory, the ICP-RCP(A-P) distance and the angle of protrusion in the sagittal trajectory differ significantly(P<0.05). 5. The significant correlation was found between orbiting condylar inclination and protrusive condylar inclination.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.255-268
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• 1998

This study was investigated to assess the difference of facial height and occlusal plane inclination between normal occlusion group and class II malocclusion group. The subjects consisted of 50 normal occlusion (male 25, female 25) and 50 class II(male 25, female 25) malocclusion patients. All subjects are adult. lateral cephalogram was taken with standard method traced, and digitized for each subjects. The computerized statiscal analysis was carried out with SPSS program. The results were as follows 1. In class II malocclusion group, variables significant different from normal occlusion group were as follows ; SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP 2. In class II malocclusion group, the posterior facial height -especially posterior lower facial height-was significantly smaller than normal occlusion group.(P<0.05) 3. In class II malocclusion group, the angles between occlusal plane and upper and lower incisor, the angle between upper molar and bisected occlusal plane were significantly larger than those of normal occlusion group. (P<0.05) 4. L1 to Mandibular plane (mm) was a unique factor of occlusal plane position that showed significant difference in class II malocclusion group. 5. The correlation between overbite and occlusal plane inclination existed in class II malocclusion group, but the correlation didn't exist in normal occlusion group.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.433-442
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• 2005

The purpose of this study was to evaluate and compare the shear bond strength of orthodontic brackets depending on the variety of adhesives and whether saliva exists, by using self-etching primer (SEP). Groups were divided according to the type of adhesive into resin adhesive (Trans bond XT) and resin-modified glass ionomer cement (Fuji Ortho LC). One group of resin adhesive used XT primer after etching with 37% phosphoric acid, and the other group used self-etching primer. One group of resin-modified glass ionomer cement only used etching for bonding, and the other group used SEP. Each of the groups were also classified by whether saliva was contaminated or not. and then the shear bond strength was measured. The results showed that when using resin adhesive, the shear bond strength of SEP was lower than the XT primer. In the resin-modified glass ionomer cement groups, the shear bond strength which depends on the priming method, did not have a meaningful difference statistically When saliva was contaminated, the group which used SEP, regardless of the adhesive variety, had a greater shear bond strength than the normal priming group. From these results, SEP showed a shear bond strength that is possible to be used clinically, regardless of the adhesive variety. It can especially be clinically useful to use SEP to bond brackets even on tooth surfaces contaminated with saliva, because it offers the appropriate bonding strength as well as shorter treatment time and easy application.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.45-53
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• 2001

Recently some studies have shown that low light intensity followed by final cure at high light intensity may result in a smaller marginal gap and may be no negative effect on material properties. The purpose of this study was to evaluate the influence of the initial cure with low intensity on the shear bond strength of dentin and the microhardness of composite resin. Twenty intact bovine teeth were prepared for shear bond strength test and each tooth sectioned to three specimens. The specimens were randomly divided into three groups according to the light intensity and curing time as follows; Group I. $450mmW/cm^2$ 40sec Group II. $300mmW/cm^2$ 20sec and $600mmW/cm^2$ 20sec Gropu III. $250mmW/cm^2$ 20sec and $450mmW/cm^2$ 20sec. Samples of each group were restored with light-cured composite resin after dentin bonding and then the shear bond strength of each specimen were measured using universal testing machine. Ten resin specimens per group were prepared. After 24 hours, the Vickers microhardness value was measured at the top and bottom surfaces. The result are as follows; 1. Mean value of low initial intensity groups(II, III) were higher than the control group(I) in shear bond strength, but no significant difference could be found. 2. No significant difference could be found between three groups in microhardness.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.539-547
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• 2008

Apert syndrome is an autosomal dominant condition characterized by craniosynostosis, midface hypoplasia, and syndactyly of the hands and feet. It occurs in about 1 of every 65,000 to 160,000 births and is caused by a mutation in the fibroblast growth factor receptor 2(FGFR2) gene. Apert syndrome typically produces acrobrachycephaly(tower skull). The occiput is flattened, and there is a tall appearance to the fore head. Ocular proptosis is a characteristic finding, along with hypertelorism and downward slanting lateral palpebral fissures. The middle third of the face is markedly retruded and hypoplastic, resulting in a relative mandibular prognathism. The reduced size of the nasopharynx and narrowing of the posterior choana can lead to mouth breathing, contributing to an open-mouth apprance. Three fourths of all patients exhibit either a cleft of the soft palate or a bifid uvula. The maxillary hypoplasia leads to a V-shaped arch and crowding of the teeth. A 6-year-old male patient visited to the Department of Pediatric dentistry, Kangnung National University of Dental Hospital. He visited the hospital to get treatment of carious teeth. The purpose of this report is to present a specific dental manifestations about the apert syndrome.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.532-538
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• 2008

Lesch-Nyhan syndrome is a rare X-linked recessively inherited disorder, caused by complete absence or decrease in activity of hypoxanthine guanine phosphoribosyl transferase(HPRT), an enzyme involved in purine metabolism. This enzyme deficiency gives rise to nephropathy symptoms, such as hyperuricosuria and hyperuricemia by excessive uric acid production and neuropathy symptoms, such as mental retardation, choreoathetosis and self mutilation behavior. Patients with Lesch-Nyhan syndrome have tendency to bite their lip, tongue and finger. In severe cases, partial or even total amputation of tongue or finger occur. Self-inflicted bites are often complicated by secondary infection to the injured site as well as pain. Furthermore tissue loss by biting results in esthetic problems. The dental management of self mutilation includes treatment with appliances such as soft mouth guard or lip bumper, extraction of all the teeth, and orthognathic surgery. We report a case of a 13 year-old boy with Lesch-Nyhan syndrome, who severely injured himself on his tongue. At first, conservative treatment using soft mouth guard was considered, but it could not prevent trauma on his tongue. Therefore, extraction of the lower anterior and posterior teeth was carried out.