• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.71-83
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• 2001

The purpose of this study was to Prove that the medial edge epithelial cells covering the secondary palatal shelves were removed by apoptosis during palatal fusion. 12 mature female rats (Suprague-Dawley) were mated overnight with male rats and sacrificed on days 15.0, 16.5, 16.75, 17.0 of pregnancy. The embryos were removed from the uterus and the heads were embedded in paraffin. The paraffin blocks were sectioned and the sections were undergone H-E staining for general histologic feature and TdT staining for detection of apoptotic cells. The obtained results were as follows. k. In the section of 16.0 and 16.5 day embryos, the palatal shelves were prior to contact and no apoptotic cells wereobserved in the medial edge epithelium. At the initial contact of Palatal shelves, there was a few apoptotic cells in the fusing epithelium. 2. In the 16.75 day embryos, the samples that epithelial seams did not lost there continuity, apoptotic cells were rarely seen at the midline epithelial seam. In contrast, a lot of apoptotic cells were observed at epithelial triangles and the junction between palatal shelves and nasal septum. 3. In the 16,75 day embryos, the samples that epithelial seams lost their continuity and disrupted to epithelial islands, large number, of apoptotic cells were observed at epithelial islands and epithelial triangles. Some apoptotic cells were also observed at the oral, nasal epithelium near the midline. 4. In the 17.0 day embryos, most of epithelial islands were disappeared and mesenchymal confluence was achieved. Apoptotic cells were rarely observed in the mesenchymal tissue which replaced epithelial islands, but there were some apoptotic cells at the epithelial triangles, oral and nasal epithelium. From the results of the study, it was revealed that medial edge epithelial cells of fusing palate were removed by apoptosis. Apoptotic cells were found mainly in the disappearing midline epithelial seam and the oral and nasal epithelial triangles at some late stages of palatal fusion.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.421-433
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• 1988

The purpose of this study was to investigate the characteristics of craniofacial morphology in adult with crowded dentition. The craniofacial morphology associated with normal and crowded of mandibular dentition was studied in lateral cephalometric radiograph obtained from 145 subjects grouped 44 males and 40 females in normal group, 33 males and 28 females in crowded group. The conclusions were as follows: Means, standard deviations and facial polygons from measurements were obtained from normal and crowded groups. Palatal plane to SN, occlusal plans to SN, mandibular plane to SN, mandibular plane to palatal plane and gonial angle measurements of crowded group were significantly different from normal group and were larger than normal group. SNA, SNB measurements of crowded group were significantly different from normal group and were smaller than normal group. Significant differences were observed between normal group and crowded groups on the basis of $SN/{\underline{1}}$, PP/1, $MP/{\bar{1}}$, and compared with normal group, upper incisors of crowded group were inclined more labially, whereas lower incisors of crowded group were inclined more lingually. Posterior facial height and ramal height were shorter in males of crowded group than those of normal group. Posterior facial height, mandibular length and posterior cranial base length were shorter in females of crowded group than those of normal group. Anterior facial height was longer in females of crowded group than those of normal group.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.73-81
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• 1999

Midpalatal suture expansion is often used for patients haying narrow maxillary arch, cleft palate, respiratory handicap with narrow nasal cavity. CGRP has been known as a modulator of pain transmission in central nervous system and a local effector to peripheral tissue causing vasodilation, increase of blood flow, modulation of immune system, regulation of macrophagic function and stimulation of bone formation. To investigate changes of CGRP-immunoreactive nerve fibers in midpalatal suture during the expansion, immunohistochemical study was performed by using rats. Experimental rats (10 weeks, 250 gm) were divided into five groups (control, 1, 4, 7, 14 days group (each n=4) and applied orthodontic force (approximately 200gm) to upper anterior incisors. Frozen sections of midpalatal suture area were immunostained by using rabbit antisera. The results were as follows. ${\cdot}$ The CGRP-immunoreactive nerve fibers were hardly observed in control group. ${\cdot}$ In 1 day group, the CGRP-immunoreactive nerve fibers were more increased around the vessels than control group. ${\cdot}$ In 4 days group, the CGRP-immunoreactive nerve fibers were more increased than control group, but not more increased than 1 day group. Vascular diameter was more enlarged. ${\cdot}$ In 7 days group, especially, hematoxilin affinity of cells was remarkable and cells were arranged along the bone margin. The CGRP-immunoreactive nerve fibers were more reduced than 4 days group and vascular diameter was also reduced. ${\cdot}$ In 14 days group, the CGRP-immunoreactive nerve fibers were similar to those of 7 days group and the irregularity of bone margin was almost recoverd. In Conclusion, the CGRP-immunoreactive nerve fibers nay be related to initial neurogenic inflammatory reaction in expanding mid-palatal suture.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.2
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• pp.81-86
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• 1989

Tumors originated from peripheral nerve tissues are neurofibroma, neurilemoma, plexiform neurofibroma, malignant schwannoma, and granular cell tumor. Neurofibromas seem to occur in two forms : The first one is circumscribed solitary neurofibroma and the second group is neurofibromatosis or Von Recklinghausen's disease, which is a congenital and familial disease, presenting abnormalities of the skin, nerve system, bones and soft tissue. A solitary neurofibroma is a benign, relatively circumscribed, noncapsulated tumor which often presents in the skin and subcutaneous tissue as a soft sessile or pedunculated mass. It may occur anywhere in the head and neck, but the common site of the occurrence is the tongue, buccal mucosa, palate in frequency. Since solitary neurofibroma is a relatively radioresistant and its recurrence rate seem to be low, the treatment of choice is surgical excision. The author would like to present a case of unusually large solitary neurofibroma occured in the chin, which was successfully treated with surgical excision and reconstructed using deltopectoral flap and tongue flap.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.149-157
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• 2016

Tooth preparation design is essential for successful laminate veneer treatment. Preservative tooth preparation limited on enamel, supra-margin advantageous for plaque control, and maintaining contact points known as a standard concept. However, the tooth preparation design has been the controversial issue. In biomechanical considerations, the incisal coverage should be decided on esthetic needs and necessity for the anterior guidance reconstruction. In occasion for sufficient enamel thickness, preparation can prolong to the palatal side but not recommended at palatal concavity. Elongation to contact point is selective option according to the cases. If an old resin restoration located at contact area, laminate veneer should cover over half area of that after surface treatment. The laminate veneer can be also selected at a partially discolored tooth root canal therapy (RCT) and at this occasion, the fiber-reinforced composite (FRC) posts are recommended.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.41-47
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• 2010

Purpose: The purpose of this study was to compare the functional abilities of the low bulb obturators with those of high bulb obturators in terms of patients' evaluation. Material and methods: This study included 11 maxillectomy patients who underwent postoperative prosthodontic rehabilitations. Two obturators of the same design except for different bulb heights, were fabricated for each of the maxillectomy patient. After two months of alternate use, the functions of the obturators were measured by investigating the patients' subjective evaluations in terms of convenience, speech, nasality, leakage, and mastication and identifying their preferred prostheses. Wilcoxon signed rank test was used as a statistical method (P < .05). Results: There were no significant differences in patient evaluations of low and high bulb obturators (P >.05). And patients' preferences varied. Conclusion: In extreme situation such as in mouth opening limitation, the use of low bulb obturators can be recommended and result in comparable speech function to that of obturators with high lateral walls.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.855-864
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• 1998

The purposes of this study were to evaluate the cephalometric characteristics of Korean female patients with Class II division 2 malocclusion and to compare Korean females with Caucasian females who had same type of malocclusion. All of the samples had Class II division 2 malocclusion with deep overbite (more than 4mm) and full permanent dentition. These samples were divided into two groups according to the races: Group 1(N=16; Korean females; average age=18Y 2M) and Group 2 (N:20; Caucasian females; average age=14Y 2M). The pretreatment lateral cephalograms were measured, analyzed and compared by using 38 variables and independent t-test. And the results were as follows: 1. Although there were no differences in Overbite, SN to mandibular plane angle, Palatomandibular plane angle, and FMA between Group 1 and 2, the other vertical relation variables of maxilla and mandible (SN to palatal plane angle, SN to occlusal plane angle, ODI) of Group 1 showed more clockwise rotation tendency of occlusal plane and less hypodivergency tendency than those of Group 2. 2. There were no differences in mandibular body length and ramus height between Group 1 and 2 except small upper genial angle of Group 1. There was less counterclockwise rotation tendency of mandible in Group 1. 3. There were no statistical significant differences in UAFH/LAFH and PFH/AFH between Group 1 and 2. 4. Although there were no differences of overjet and anteroposterior position of mandible between Group 1 and 2, the position of maxilla of Group 1 was more retropositioned than that of Group 2. 5. Except the more protrusion of lower incisor to A-Pog of Group 1, there were no differences of inclination and distance of upper and lower incisors to basal plane between Group 1 and 2. 6. The distance from upper- first molar to palatal plane showed no difference between Group 1 and 2. But the distance from lower first molar to mandibular plane of Group 1 was greater than that of Group 2. So it may be partially related to the clockwise rotation of occlusal plane and the less counterclockwise rotation tendency of mandible of Group 1. 7. Group 1 had more protrusive upper and lower lips than Group 2.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.66-76
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• 2010

Objective: Obstructive sleep apnea (OSA) is a common disorder which is characterized by a recurrence of entire or partial collapse of the pharyngeal airway during sleep. A given tidal volume must traverse the soft tissue tube structure of the upper airway, so the tendency for airway obstruction is influenced by the geometries of the duct and characteristics of the airflow in respect to fluid dynamics. Methods: Individualized 3D FEA models were reconstructed from pretreatment computerized tomogram images of three patients with obstructive sleep apnea. 3D computational fluid dynamics analysis was used to observe the effect of airway geometry on the flow velocity, negative pressure and pressure drop in the upper airway at an inspiration flow rate of 170, 200, and 230 ml/s per nostril. Results: In all 3 models, large airflow velocity and negative pressure were observed around the section of minimum area (SMA), the region which narrows around the velopharynx and oropharynx. The bigger the Out-A (outlet area)/ SMA-A (SMA area) ratio, the greater was the change in airflow velocity and negative pressure. Conclusions: Pressure drop meaning the difference between highest pressure at nostril and lowest pressure at SMA, is a good indicator for upper airway resistance which increased more as the airflow volume was increased.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.45-54
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• 2006

Recent beauty trends have caused an increase in the number of bialveolar protrusion patients seeking treatment of lip protrusion. But studies of these patients are not common. Studies using their dental models are especially rare. Dental models have been measured manually or through a computer by digitizing two dimensional images of models. Nowadays, we are able to study dental models more easily and accurately by utilizing the three-dimensional (3-D) laser scanner in dentistry. An investigation was carried out to evaluate the characteristics of the dental arch in a bialveolar protrusion group in comparison with a normal group using 3-D digital models. The normal group was composed of 20 subjects who were selected from students of the School of Dentistry, Kyungpook National University. The bialveolar protrusion group was composed of 20 subjects who visited for treatment at the Department of Orthodontics, Kyungpook National University Hospital. Tooth size, arch width and arch length were measured digitally, and arch shape and the shape of the palate were drawn. Based on the results of this study, the differences of the arch characteristics in the bialveolar protrusion group were that the size of the teeth was larger, mandibular canine width and 1st premolar width were wider, and arch length was longer than in the normal group. And there were differences in the arch shape and the shape of palate between the bialveolar protrusion and normal groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.166-170
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• 2001

Rubinstein-Tabyi syndrome(RTS) is a congenital multisystem dysmorphic syndrome with many non-specific features, making diagnosis occasionally difficult. The major features of this syndrome include mental retardation, characteristic facial appearance, short stature, microcephaly, and broad thumbs and halluces. This syndrome was first described by Rubinstein and Tabyi in 1963, and many studies have been continued about this syndrome, but specific pathogenesis of the Rubinstein-Tabyi syndrome phenotype is still not clear. High arched palate, micrognathia and multiple caries etc have been reported in Rubinstein-Tabyi syndrome. In this report, a 6-year and 5-month-old boy visited at our department due to multiple dental caries, who showed broad thumbs, mental and physical development retardation, and characteristic facial appearance including both ptosis and ear deformity. This patient was diagnosed as a Rubinstein-Tabyi syndrome, and treated the multiple dental caries under general anesthesia. This study was aimed to observe the relationship between medical and dental characteristics.