• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.169-179
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• 2004

The purpose of this study was to discriminate clinically and radiographically among the three groups of dentigerous cysts studied. First, Group I, involved area of dentigerous cyst was successive permanent tooth area beneath deciduous tooth. Second, Group II, involved permanent molar area, and the last, Group III involved maxillary anterior supernumerary tooth area. The author observed and compared the clinico-radiographic features of 49 cases of Group I, 36 cases of Group II, and 15 cases of Group III of dentigerous cyst and this observation and comparison had been done by based on the charts and panoramic films. The obtained results were as follows: 1. The cases of Group I were 29 cases and, those of Group II were 36 and those of Group III were 15. 2. The incidence of dentigerous cyst is high in first decade. In Group I, before first decade and early first decade was 87.8%, in Group II and Group III, was discovered more lately. 3. The frequency of dentigerous cyst is 2.5 times higher in male than in female. 4. The sequence of chief complaint was swelling(50%), routine examination(32%), and pain(9%). 5. When considering the type of the cyst, lateral type is many most in Group I (71.4%) and central type is many most in Group II (94.4%) and Group III (100%). 6. The most size of dentigerous cyst was 2 crown size in Group I, 1 crown size in Group II, above of 4 crown size in Group III. 7. Almost involved teeth showed displacement and some tooth of displaced teeth showed delayed root development and dilaceration of root. 8. The most many response of alveolar bone was buccal bone expansion in Group I (67.3%), no bone expansion in Group II(66.7%) and palatal bone expansion in Group III (60.0%). 9. The percentage of involved teeth were as follows : The mandibular third molar was 31% and many most. The mandibular second premolar was 30%. Mesiodens of maxillary anterior area was 15%. The maxillary canine was 8%. The mandibular first premolar was 5%. 10. In the Group I, causes suggesting of dentigeous cyst are pulpotomized deciduous tooth(59.2%), severe dental caries of deciduous tooth, untreated traumatic history on the deciduous tooth etc. 11. The treatment method of dentigerous was marsupialization in 61.2% of cases of Group I and that was enucleation in 61.1% of cases of Group II and in 80.0% of cases of Group III.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.1-14
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• 1999

Ursodeoxycholic acid(UDCA) is a hydrophilic gall bladder acid and has been used as a effective drug for liver disease related to in1munity. This drug inhibits secretions of IL-2, IL-4, and $IFN-{\gamma}$ from T-cells and production of immunoglobulin from B-cells. Also it has been reported that UDCA inhibits production of IL-1 related to the progression of periodontal disease and activation of collagenases. The purpose of the present study was to elucidate the effects of UDCA on inhibition of periodontal disease progression using clinical, microbiological and histometrical parameters. Twelve pure bred, 16 month-old-beagle dogs were used in the study. After ligature-induced periodontal diseases were formed, experimental drugs were applied twice a day and then the results of clinical, microbiological, and histometrical parameters were measured at baselie(initiation of experiment) , 4weeks and 8weeks. The gel with UDCA(concentration 0.5%, 5% 3 dogs in each) was applied to experimental group, chlorhexidine to positive control group(3dogs) and the gel without UDCA(base) to negative control group. After induction of general anesthesia, the maxillary 2nd, 3rd premolars and 1st molar and the mandibular 2nd, 3rd, 4th premolars and 1st molar were ligated in one side selected randomly and were not ligated in the opposite side. The plaque index(PI), gingival index(GI), pocket depth(PD) and gingival crevicular fluid(GCF) volum were measured clinically. The PI and GI were measured at 3 buccal points of all experimental teeth and the GCF was measured only at the 3rd premolar in the maxilla and the 4th premolar in the mandible. In the microbiological study, the samples extracted from the 3rd premolar of the maxilla and the 4th premolar of the mandible at the center of buccal surface were analyzed aerobics, anaerobics and Streptococcus colony forming units, After clinical and microbiological examination at 8weeks, the dogs were sacrificed by carotid artery perfusion. The samples were fixed and sectioned including interproximal area, and the distance from cementoenamel junction(CEJ) to alveolar crest was measured. The results were that PI, GI and PD increased until 4 weeks and decreased at 8 weeks in three groups but the differences between all the groups were not significant. The 0.5% UDCA in non-ligated group showed remarkable decrease of GCF. The experimental group applied 5% UDCA decreased the number of aerobics and anaerobics. The distance from CEJ to alveolar crest was greater in the negative control group on both ligated and non-ligated sides, but the differences were not significant stastically.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.3
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• pp.226-237
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• 2005

Purpose : Extensive defect of oral and maxillofacial area is usually reconstructed with composite flap including skin paddle. However, if the defects are lined with only skin components, the mucosa's role in mastication and texture are not restored. Furthermore, stiffness and hair-growing prevent denture rehabilitation and good oral hygiene. This study was performed to overcome the disadvantages of composite soft tissue flaps including the skin and to make a model for myo-mucosal flaps. Materials and methods : Buccal mucosa sized $0.5\times1.0\;cm^2$ from New Zealand rabbit (around 1.5kg) was harvested and cultivated by the modification of Rheinwald and Green's keratinocyte culture method. Cultured mucosa was grafted on the fascia of latismus dorsi as form of mucosal sheet. After 7, 10, 14 days, the myomucosal flap was excised and evaluated under light microscope with H & E and immunohistochemical staining. As control group, harvested buccal mucosa from rabbit was transplanted to gracilis muscle(n=6). Results : From 7 days after prelamination, the basal layer of the grafted mucosa resembled that of normal mucosa. As control group, transplanted mucosa had original shape but there's slight inflammatory reaction. Prelaminated mucosa has 19.8$\pm$4.59 cell layers and some samples have more than 20 layers. The expression rate of PCNA was relatively strong (42.9%$\pm$14.1) at the basal layer of grafted mucosa and the laminin was found at the basal layer. On the contrary, prelaminated mucosa at 10 days showed moderate expression rate of PCNA(32.4%$\pm$4.62). We found the mucosal layer was somehow disappeared and there is strong inflammatory reaction. After 14 days prelamination, the grafted oral keratinocytes were almost disappeared and expression of PCNA was not observed. Conclusion : We can make 75 fold large mucosal($3850mm^2$) sheet from small samples of mucosa $(50mm^2)$. Epithelial sheet that grafted on the fascia of muscle underwent differentiation and proliferation. But after 10, 14 days, there was strong inflammatory reaction and the grafted mucosa was destroyed from surface layer. In rabbit model, transfer of fascio-mucosal flap should be done from 7 to 10 days after prelamination.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.179-195
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• 2010

In the internal connection system, the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. The purpose of this study was to assess the loading distributing characteristics of three different abutments for GS II$^{(R)}$ implant fixture(Osstem, Korea) under vertical and inclined loading using finite element analysis. Three finite element models were designed according to three abutments; 2-piece Transfer$^{TM}$ abutment made of pure titanium(GST), 2-piece GoldCast$^{TM}$ abutment made of gold alloy(GSG), 3-piece Convertible$^{TM}$ abutment with external connection(GSC). This study simulated loads of 100N in a vertical direction on the central pit(load 1), on the buccal cusp tip(load 2) and $30^{\circ}$ inward inclined direction on the central pit(load 3), and on the buccal cusp tip(load 4). The following results were obtained. 1. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture and lower stress was taken at the cancellous bone. 2. When off-axis loading was applied, high stress concentration observed in cervical area. 3. GSG showed even stress distribution in crown, abutment and fixture. GST showed high stress concentration in fixture and abutment screw. GSC showed high stress concentration in fixture and abutment. 4. Maximum von Mises stress in the surrounding bone had no difference among three abutment type. In GS II$^{(R)}$ conical implant system, different stress distribution pattern was showed according to the abutment type and the stress-induced pattern at the supporting bone according to the abutment type had no difference among them.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.199-207
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• 2001

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop Produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.220-230
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• 2007

Objective: The purpose of this study was to determine the changes of mandibular anterior alveolar bone thickness with age. Methods: Cephalometric radiographs of 160 skeletal class I patients (male 80, female 80) with normal vertical growth pattern was investigated by measuring the buccolingual thickness of mandibular alveolar bone on the basis of root axis. Results: As the age increases, both male and female showed a significant decrease in buccolingual width of the mandibular anterior alveolar bone and in the width of mandibular anterior lingual alveolar bone except the CEJ area of females. However, there was no significant difference in the thickness of mandibular anterior buccal alveolar bone and in the width of maximum prominence of mandibular symphysis with age. Conclusion: From the above results, it is concluded that Korean children whose growth pattern is sagittally skeletal class l with a vertical normal growth pattern have a greater mandibular anterior lingual alveolar bone width than Korean adults; therefore, lingual movement of mandibular incisors, which is usually accompanied in extraction treatment, is considered to be more preferable in younger patients.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.2
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• pp.226-237
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• 2004

Purpose: Four finite element models were constructed in the mandible having a single implant fixture connected to the first premolar-shaped superstructure, in order to evaluate how the shape of the fixture and the implant-abutment connection would influence the stress level of the supporting tissues fixtures, and prosthethic components. Material and methods : The superstructures were constructed using UCLA type abutment, ADA type III gold alloy was used to fabricate a crown and then connected to the fixture with an abutment screw. The models BRA, END , FRI, ITI were constructed from the mandible implanted with Branemark, Endopore, Frialit-2, I.T.I. systems respectively. In each model, 150 N of vertical load was placed on the central pit of an occlusal plane and 150 N of $40^{\circ}$ oblique load was placed on the buccal cusp. The displacement and stress distribution in the supporting tissues and the other components were analysed using a 2-dimensional finite element analysis . The maximum stress in each reference area was compared. Results : 1. Under $40^{\circ}$ oblique loading, the maximum stress was larger in the implant, superstructure and supporting tissue, compared to the stress pattern under vertical loading. 2. In the implant, prosthesis and supporting tissue, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 3. In the superstructure and implant/abutment interface, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 4. In the implant fixture, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 5 The stress was more evenly distributed in the bone/implant interface through the FRI of trapezoidal step design. Especially Under $40^{\circ}$ oblique loading, The maximum stress was smallest in the bone/implant interface. 6. In the implant and superstructure and supporting tissue, the maximum stress occured at the crown loading point through the ITI. Conclusion: The stress distribution of the supporting tissue was affected by shape of a fixture and implant-abutment connection. The magnitude of maximum stress was reduced with the internal connection type (FRI) and the morse taper type (ITI) in the implant, prosthesis and supporting tissue. Trapezoidal step design of FRI showed evenly distributed the stress at the bone/implant interface.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.490-496
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• 2010

Introduction: This study examined the effect of a conservative neck dissection in patients with head and neck cancer. Materials and Methods: A total of 24 patients, who underwent a conservative neck dissection for the treatment of oral cancer from January 2002 to December 2007, were included. All procedures were performed by one oral and maxillofacial surgeon. The mean age was 58.2 years (range, 19 to 79 years). The medical recordings, pathologic findings, and radiographic findings were evaluated. The mean follow up period was 41.1 months (range, 4 to 88 months). Results: 1. Oral cancer was more common in men than women with a 3:1 ratio. 2. Histopathologically, squamous cell carcinoma(83%) was the most prevalent oral cancer in this study. 3. The most common primary site was the tongue(6 cases, 25%) followed by the mouth floor (5 cases, 21%), buccal mucosa (3 cases, 13%), lower lip, mandible, palate (2 cases, respectively) and salivary gland, retromolar area, oropharynx, alveolus (1 case, each). 4. Three out of the 24 (13%) subjects had a recurrence at the primary sites. 5. Two out of 24 (8%) subjects had a distant metastasis. 6. All 24 patients survived and there were eleven patients who passed 5 years postoperatively. Conclusion: A conservative neck dissection is a reliable and effective method for controlling neck node metastases in patients with oral cancer of the N0 or N1 neck node without serious complications.

• Journal of Oral Medicine and Pain
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• v.35 no.4
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• pp.259-264
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• 2010

The majority of chronic gingival ulcerative lesions are known to be due to autoimmune disease such as oral lichen planus, benign mucous membrane pemphigoid or pemphigus vulgaris. Topical or systemic corticosteroids are mainly used and adjuvant drugs like immunosuppressant, anti-inflammatory drugs, antimalarials or antimetabolites can also be prescribed. Because systemic corticosteroids causes various side effects, such as gastrointestinal disturbance, osteoporosis, diabetes or adrenal suppression. So, topical steroid therapy is main treatment for chronic gingival ulcerative lesion confined to small area. However, there's also limitation of topical corticosteroids. The effect of the corticosteroids decreases due to salivary flow and the movement of the tongue, lips, or buccal mucosa. When the lesions are widely distributed or positioned deeply in oral cavity, it is hard to apply the medication on patients' own. Moreover, it can be applied to unaffected mucosa. Although occlusive steroid therapy using stent was reported to minimize taking steroid and overcome the faults of applying topical steroids, it has been used less frequently in the clinical field. Therefore, this report is going to find out the usefulness and the way to utilize clinically through the case which acted satisfactorily by performing topical steroid therapy using stent on chronic ulcerative gingival lesions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.497-503
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• 2004

One of the most difficult problems to damage in dentistry is an odontogenic infection. These infections may range from low-grade, well-localized infections that require only minimal treatment to a severe, life-threatenig fascial space infection. Although the overwhelming majority of odontogenic infections are easily managed by minor surgical procedures and supportive medical therapy that includes antibiotic administration, the practitioner must constantly bear in mind that these infections may become severe in a very short time. We made an investigation was targeting on 78 male and 47 female patients (125 patients in total) who had been hospitalized because of the fascial space abscess on the oral and maxillofacial area and gained a complete recovery in Daegu Catholic University Hospital, Oral & Maxillofacial Surgery from January 1999 to December 2003. By tracing their charts, we could grasp the characteristics such as age, gender, the time of breakout and specific areas of the attacks, making a conclusive study of the statistical analysis and finally, we could reach conclusions. Now, we report the conclusion from the investigation with the literature. The proportion of males and females was approximately 3 to 2, and in age group, patients under 10 years old marked the highest, 22.4%. The patients between the age of 10 and 40 were only 14.4%, yet those who were between 40 and 80 marked 53.6% in contrast. In the monthly distribution, the order was Dec.(13.6%)-Sep.(12%)-Jan.(10.4%) and in seasonal distribution, it was winter(30.4%)-fall(28%)- summer(24.4%)- spring(19.2%). Considering the medical history, D.M. was the highest which was 30.3%, hypertension marked 24.4%, and the patients with both D.M. and hypertension were 9.0%. The major cause of infection of oral and maxillofacial areas was odontogenic infection, which marked about 96%, and especially the cases related to dental caries occurred most frequently, which was 51.2%. In the number of relaxed fascial space, single fascial space was 81.6%, and in the degree of relaxation of fascial space, the buccal space abscess marked 40.8%, following submandibular space abscess, which was 30.4%.