• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.554-563
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• 1999

For the purpose of elucidating the polymerization modes of dual-cure restorative materials and comparing them with single-cure restorative materials, a study was performed on the light-cured composite resin, dual-cure composite resin, dual-cure glass ionomer cement and chemical-cure glass ionomer cement. By measuring the microhardness of each material at 0mm, 1mm and 3mm depth during initial 24 hours with predetermined interval, the state of polymerization and degree of conversion was indirectly evaluated for each material, and obtained results are as follows : 1. All of four materials tested showed significant increase in microhardness after 24hrs compared with just after curing starts. 2. In all materials except Ketac-fil, there showed a significant difference in microhardness between each depth at each time interval. 3. In the test of lap time till final curing for each material, the polymerization process was revealed to last longer in the dual-cure type materials than in single-cure type materials at 3mm depth. Based on the results above, it was demonstrated with materials of dual-cure mode that the degree of conversion increases by successive curing reactions even in the deeper layers where sufficient curing light is impermeable.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.741-750
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• 1998

This study was designed to evaluate the Personality characteristics of orthognathic surgery patients preoperatively and postoperatively through the MMPI. Comparison was made between the personality characteritics of preoperative and postoperative groups. Motivation for undergoing orthognathic surgery and postoperative satisfaction were examined through the questionnaire. Subjects used in this study consisted of 50 patients under presurgical orthodontic treatment and 22 patients who had received orthognathic surgery. From this study, the results were followings. 1. In preoperative patients group, all T-scores were within the normal range except for K-scale. The T-score of K-scale is 57.7, this showed that these patients underwent some or less stress. 2. In postoperative patients group, all T-scores were within the normal range. 3. Only in K-scale, there was statistically significant increase after surgery (p<0.05). 4. In male patients group, all T-scores were within the normal range except for that of preoperative K-scale. Postoperatively, there were statistically significant increase in K and Hs scales(p<0.05) 5. In female patients group, all T-scores were within the normal range. 6. Motivation for undergoing orthognathic surgery could be divided into 4 categories. esthetic goal($28.2\%$), functional goal($32.1\%$), TMJ problem($9.0\%$), and psychosocial reason($30.7\%$). 7. The degree of postoperative satisfaction was quite high($85.7\%$). $14.3\%$ of all patients were very satisfied, $71.4\%$ were satisfied, $9.5\%$ were neither satisfied or dissatisfied, and $4.8\%$ were very dissatisfied.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.582-595
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• 2003

Statement of problem : Most posts are metallic, but in response to the need for a post that possesses optical properties compatible with an all-ceramic crown. an esthetic post has been developed. Although there have been many studies about the esthetic post materials, 3-dimensional finite element studies about the stress distribution of them are in rare. Purpose : The purpose of this study is to investigate comparatively the distribution of stresses of the restored, endodontically treated maxillary incisors with the esthetic post materials and the displacement on the cement layer on simulated occlusal loading by using a 3-dimensional finite element analysis model. Material and method : Four 3-dimensional finite element models were constructed in a view of a maxillary central incisor, a post, a core, and the supporting tissues to investigate the stresses in various esthetic posts and cores and the displacement on the cement layer (Model 1 ; Cast gold post and core, Model 2 ; Glass fiber post with composite core, Model 3 ; Zirconia post with composite core. Model 4 ; Zirconia post with ceramic core). Force of 300N was applied to the incisal edge and the cingulum (centric stop point) with the angle of 135-degree to the long axis of the tooth. Results : 1. The stresses and displacement on the incisal edge were higher than on the cingulum 2. The stresses in dentin were the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. 3. The stresses in post and core were the highest in Model 4 (Zirconia post with ceramic core), and the second was Model 1, the third Model 3, and the lowest Model 2. 4. The displacement on the cement layer was the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. Conclusion : When a functional maximum bite force was applied, the distribution of stresses or the esthetic post and core materials and the displacement on the cement layer were a little different. It seems that restoring extensively damaged incisors with esthetic post and core materials would be decided according to the remaining tooth structure.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.640-655
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• 2003

Statement of problem : The beauty has a little different meaning according to a time, culture, and nation. Purpose : This study was undertaken to determine the Korean perception of the altered upper anterior dental esthetics including the lack of symmetry, the midline deviation, the gingival exposure, the inclination of incisal plane, the type of incisal plane, and the type of gingival line. Material and Method : 670 subjects were participated in this survey. A questionnaire accompanied by 12 sets of computer-manipulated images using 3D MAX 4.2 software was used to record the ranking of the geometric preference related to the anterior esthetic discrepancies in three or four degrees of alteration. The statistical significance of the differences between the groups was determined by a one-way ANOVA and a t-test. Results : The results obtained were as follows: 1) The Korean perception of the anterior dental esthetics according to the subjects' occupation, sex, and age was most affected by occupation. 2) The masked image emphasizing the dentition and lips appeared stranger than the non-masked image at the same alteration. 3) The lack of symmetry, which was expressed as a unilateral discoloration of the tooth, showed incongruity in any teeth of the anterior dentition. The incongruity was more severe as the degree occurred closer to the midline. 4) The deviation of midline was showed more severe strangeness as the degree of deviation increased. However, more than half of the subjects did not perceive a deviation of 5mm. 5) During smiling, the exposure of the upper gingiva showed more severe incongruity as the degree of gingival exposure increased. 77% of the subjects perceived strangeness at the gingival exposure of 4.5mm. 6) The inclination of the incisal plane appeared stranger as the degree of inclination increased. 62% of subjects perceived strangeness at the $7.5^{\circ}$ inclination of the incisal plane. 7) The type of incisal plane showed increasing strangeness in the order of convex/downward, straight/horizontal, and concave/upward. 80% of subjects perceived strangeness at concave/upward. 8) The type of gingival line was showed increasing incongruity in the order of the same, a little above, and a little under the zenith of the lateral incisor to the line joining the zenith of the central incisor and the canine. However, less than half the subjects did not perceive strangeness at any alteration of the gingival line. Conclusion : The Korean perception of the upper anterior dental esthetics was different to the westerner's perception in the some respects.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.156-163
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• 2017

People with class I intellectual disability need lifelong assistance and protection from their surroundings due to impaired adaptive functioning. They have poor oral health and show higher prevalence of dental caries, periapical inflammation and tooth loss that require proper prosthetic restoration. Because removable prostheses for intellectually disabled patients often lack stability, retention, and maintenance, fixed prostheses are essential and the only available option is dental implants. In this case, a 45 year-old male patient with class I intellectual disability had poor oral hygiene with most of his teeth missing and visited the clinic to recover his masticatory function. Due to such systemic conditions, the definitive restoration of choice was the implant-supported fixed dental prosthesis made of biocompatible and highly strong monolithic zirconia. In consequence of the treatment process, the patient was able to improve his oral environment aesthetically and functionally.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.375-383
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• 2018

Clinicians are faced with many difficulties when planning prosthodontic restorations with implants in a complete edentulous patient. When planning fixed implant prosthetics, it is often necessary to have additional surgery due to highly reduced alveolar bone, as well as high treatment costs and long-term treatment durations can be required. In addition, lack of interocclusal space can be a problem when planning implant supported overdentures. In this study, we planned to place a small number of implants on the anterior maxilla and used them as the abutments for distal-extension removable partial dentures on the posterior side in a maxillary fully edentulous patient. This would reduce the possibility of additional invasive operations such as alveolar bone graft, shorten the treatment time, and be relatively easy for elderly patients to burden. In this case, the patient was provided with a distal-extension removable partial denture and anterior implant fixed prostheses, which was similar to the previous one, and showed good adaptation, and chewing efficiency and esthetics was recovered.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.331-338
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• 1999

Chemoradiation therapy used on pediatric oncology patients often causes dental developmental anomalies that affect future dental care. Defects noted include tooth and root agenesis, root thining and shortening, and localized enamel defects. The effect of radiotherapy usually are confined to the radiation site, but the effects of chemotherapy may be more wide spread because of its systemic distribution and structures and organs unrelated to the primary tumor may be affected. Many pediatric cancers are treated with a combination of radiation and multiagent chemotherapy to create synergic and additive effects. Dental treatment affected by chemoradiation damage to developing teeth includes orthodontic tooth movement, prosthetic abutment considerations, periodontal health, space maintenance, requirements for home fluoride regimens to protect hypomineralized areas, restoration options for hypoplastic/hypomineralized teeth, and endodontic procedures. The following case demonstrate chemoradiation therapy effects on the dental development.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.317-322
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• 1999

Dens invaginatus is a developmental anomaly resulting from an invagination of the enamel organ. The incidence is highest with maxillary permanent lateral incisors. The reported occurrence ranges from 0.04 to 10%. This anomaly may involve the pulp and periapical tissues and cause pulpal inflammation, loss of vitality, apical and lateral periodontitis, periapical abscesses and cysts and stimulate internal resorption. Oehlers describes dens invaginatus as occurrence in three forms. In treating type 3 invaginatus, treatment strategy can be determined by considering the complexity and accessibility of invagination. In this case, showing simple invagination, it could be treated by simple endodontic treament confining to invagination without loss of vitality of tooth. After treatment of the present case, the results were as follows: 1. In type 3 dens invagiantus, if the tooth is vital and there is no evidence of communicating between invagination and pulp, we can save the vitality of the tooth and resolve the lesion by endodontic treament confining to the invagination. 2. In the invagination with opened apex, the closure of apex can be induced by apexification procedure doing this, we can avoid the neccessity of surgical intervention.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.293-300
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• 2012

In case of treating the functional type of anterior cross bite, removing the cause in early stage prevents from turning to skeletal type, leads to perform normal function, and has improved facial appearance. Functional Regulator III (FR III), one kind of the Functional regulator(FR)s suggested by R$\ddot{o}$lf Fr$\ddot{a}$nkel in 1966, applied to patients with the functional and skeletal anterior crossbite in early mixed, and permanent dentition. This appliance improves unbalanced power condition by blocking abnormal muscle-power effect, so that normal growth can be expected. In this case report, favorable results were obtained by selecting clinical cases of children in their early mixed dentition with functional cross bite. 1. FR IIIs were applied to patients with anterior crossbite for 5~6 months. Anterior crossbite patients were corrected favorably, nevertheless they didn't show any horizontal skeletal-changes by buccal shields. 2. Normal occlusion and esthetic facial contour were achieved from dental movement of maxillary and mandibular anterior teeth while the mandible rotates to posterior and inferior direction.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.281-287
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• 2009

An eruption failure can be observed for child and adolescent periods when the primary dentition is changed to the permanent dentition through the mixed dentition frequently. The eruption failure can lead to miss erupting times of the tooth, then it will cause a lot of problems including root resorption, esthetic problem, transposition of adjacent tooth, malocclusoin and etc. Especially, the maxillary first molar is importantly concerned with occlusion and growth and is an essential tooth for development and maintenance of occlusion. So, it is a momentous part of more proper occlusal management to find these abnormal cases at the early stage and solve the problems. The sorts of eruption failures of the maxillary first molars can be divided into delayed eruption, impaction and the primary retention and the secondary retention. When physical obstacles cause impaction, first of all they must be removed then we can treat the impaction with observation after removal, surgical exposure or orthodontic traction. If the source of impaction is an ectopic eruption, the treatment can be a brasswire, a pendulum appliance, a space maintainer or space regainer after the extraction of the second deciduous tooth and etc. These cases are made a diagnosis of eruption failures of the maxillary first molars in mixed dentition period and have good prognosises after my treatments. So I reported them.