• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.165-174
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• 1990

The purpose of the study was to correlate margin design(chamfer, shoulder, shoulder with a $45^{\circ}$ bevel. with the seating and sealing of cemented full cast crowns under standardized simulated clinical conditions. Wax patterns were made with milled stainless-steel dies and rings, and were invested, burnt out, and cast. The full cast crowns were comented on individual resin dies, and a gradually diminishing load(45kg to 25kg. was applied over a 10-minute period. The specimens were sectioned centrally with a low speed diamond saw and examined with light microscope. The results were as follows : 1. Chamfer preparations demonstrated it was the best marginal seal, followed in order by the shoulder with a $45^{\circ}$ bevel, and by the shoulder(p<.05). 2. Chamfer preparations demonstrated it was the best occlusal seating, followed in order by the shoulder, and by the shoulder with a $45^{\circ}$ bevel(p<.05).

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.8 no.2
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• pp.109-112
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• 2012

Epidermolysis bullosa (EB) is an inherited skin disease characterized by blister formation of the skin following just minor trauma or spontaneously. The main classification of EB is based on the localization of the blistering. In epidermolysis bullosa simplex, the blister formation is intraepidermal; in epidermolysis bullosa junctionalis the blister formation in the epidermal-dermal junction; in the dystrophic forms of EB blister formation is intradermal. Oral manifestations of recessive dystrophic EB are characterized by rampant caries, crowding, microstomia, ankyloglossia, vestibular obliteration. Dental therapy may be well provided to patient with recessive dystrophic EB by using general anesthesia especially in case of poor cooperation. A two years old girl with recessive dystrophic EB visited our clinic for rampant caries. She was hospitalized for severe anemia and fever, and we provided dental therapy under general anesthesia. Extraction of incisors and stainless steel crown restoration of primary molars were performed.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.14 no.1
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• pp.31-35
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• 2018

Dentinogenesis imperfecta is a hereditary disorder that causes abnormal dentin formation and tooth morphology. Affected teeth show very thin dentin and large pulp chamber. Immediately after their eruption, the teeth tend to be destroyed rapidly. Early dental intervention is recommended to improve the feeding capacity and quality of life for the child, to maintain vertical dimension, and to promote healthy and functional dentition. This case report describes a treatment for a 4-year-2-month-old girl whose primary and permanent dentition were affected by Dentinogenesis Imperfecta. Shell teeth were observed in the entire primary dentition. The pulp of most teeth was exposed and the patient complained of pain. Most paternal family members were transferred to the Dentinogenesis Imperfecta. She needed an extensive dental treatment, but her compliance could not be expected because she was very young and anxious. So we decided to treat her under general anesthesia. All molar teeth are restored with Stainless Steel crown. Maxillary anterior teeth were extracted and mandibular anterior teeth are restored with composite resin. The patient's pain disappeared and masticatory function was restored.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.504-509
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• 2006

Pediatric dentistry is differentiated from other fields of dentistry in that it provides comprehensive dental care for children and adolescents. In early days, pediatric dentistry used to be confined to the caries treatment and extraction of primary teeth However, the practice spectrum of pediatric dentistry has broadened to the orthodontic, surgical, esthetic and preventive treatments A survey that contained questions about practice patterns were mailed to 50 pediatric dentists, and 21 surveys were returned. Results were as follows: 1. The average number of patients per week was 82.4, and the average number of treated teeth per patient was 2.35. 2. Preventive treatments comprised 15.7%, restorative treatments 55.7%, endodontic treatments 15.6%, surgical treatments 10.5%, and orthodontic treatments 2.4%. 3. In restorative treatments, amalgam restoration comprised 3.8%, glass ionomer 5.5%, composite resin 63.0%, and stainless steel crown 27.7%.

• The korean journal of orthodontics
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• v.45 no.6
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• pp.299-307
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• 2015

Objective: The aims of this study were to compare the shear bond strength between orthodontic metal brackets and glazed zirconia using different types of primer before applying resin cement and to determine which primer was more effective. Methods: Zirconia blocks were milled and embedded in acrylic resin and randomly assigned to one of four groups: nonglazed zirconia with sandblasting and zirconia primer (NZ); glazed zirconia with sandblasting, etching, and zirconia primer (GZ); glazed zirconia with sandblasting, etching, and porcelain primer (GP); and glazed zirconia with sandblasting, etching, zirconia primer, and porcelain primer (GZP). A stainless steel metal bracket was bonded to each target surface with resin cement, and all specimens underwent thermal cycling. The shear bond strength of the specimens was measured by a universal testing machine. A scanning electron microscope, three-dimensional optical surface-profiler, and stereoscopic microscope were used to image the zirconia surfaces. The data were analyzed with one-way analyses of variance and the Fisher exact test. Results: Group GZ showed significantly lower shear bond strength than did the other groups. No statistically significant differences were found among groups NZ, GP, and GZP. All specimens in group GZ showed adhesive failure between the zirconia and resin cement. In groups NZ and GP, bonding failed at the interface between the resin cement and bracket base or showed complex adhesive and cohesive failure. Conclusions: Porcelain primer is the more appropriate choice for bonding a metal bracket to the surface of a full-contour glazed zirconia crown with resin cement.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.598-603
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• 1998

Amelogenesis imperfecta is a group of hereditary defects of enamel unassociated with any other generalized defects. The prevalence of this condition has been estimated to range from 1 in 14,000 to 1 in 16,000, depending on the population studied. It may be differentiated into three general types : hypoplastic, hypocalcified, and hypomaturation, depending on the clinical presentation of the defects and the likely stage of enamel formation that is primarily affected. The dentin and root form are usually normal, but the enamel may lack the normal prismatic structure, being laminated throughout its thickness or at the periphery, with the result that these teeth are more resistant to decay. This case is that of an six-year-old girl brought to the pediatric dentistry department by her parents for esthetic reasons and also because of slight dental sensitivity. Clinical and radiographic examinations confirmed amelogenesis imperfecta. The author has treated with the crowning of the primary molars, using prefomed NiCr crowns and periodic fluoride application on whole dentition.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.12 no.2
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• pp.87-91
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• 2016

Pierre Robin syndrome (PRS) is characterized by the triad of congenital mandibular hypoplasia, glossoptosis and cleft palate. Infant PRS patients are frequently suffering from upper airway obstruction, gastroesophageal reflux and growth retardation caused by above mentioned problems. We report a dental caries treatment of 3-year old girl with Pierre Robin syndrome with multiple caries. The cause of multiple caries was mainly presumed as patient's eating habit caused by her general condition. She had some feeding problems and had history of gastric tube. She was still using milk bottle and took more than an hour to finish a meal. The treatment was performed under general anesthesia considering patient's condition; mild autism, poor cooperation and respiratory problem due to micrognathia. Severely affected upper incisors were treated with pulp treatment and restored with zirconia crown for esthetic purpose. Lower incisors were treated with pulp treatment and restored with composite resin. Upper right first primary molar was restored with stainless steel crown and other primary molars were treated with composite resin. There were no postoperative complications. According to her parents, the patient's compliance to oral hygiene management was greatly improved after the treatment since she was very pleased with the esthetic result and highly motivated by her looks. The treatment without sedation or general anesthesia would be possible once the airway is improved as the mandible grows.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.15 no.1
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• pp.50-54
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• 2019

Muscular dystrophy (MD) is a heterogeneous group of inherited neuromuscular disorders, characterized by progressive muscle weakness. Severity of the disease ranges from mild to severe, and the disease is mostly caused by mutations in a number of genes. These genetic mutations cause lack of proteins which are essential for muscle cell stability. Muscle fibers are gradually replaced by fat and fibrous tissue. The muscles of the head and neck are affected in several types of MD that manifest as altered craniofacial morphology and dental malocclusion. A 3-year-10-month old, 15.0 kg boy with MD presented to Seoul National University Dental Hospital, Seoul, South Korea because of extensive carious teeth. A number of dental caries in primary dentition were identified during clinical oral examination. Due to dental anxiety and underlying systemic disease, general anesthesia was considered. General anesthesia was induced and maintained with intravenous anesthetics, propofol and remifentanil. Caries treatments - resin restoration, pulpectomy, zirconia crown restoration, stainless steel crown restoration - were performed. Under general anesthesia, successful dental procedure was done. Total intravenous anesthesia (TIVA) was performed instead of inhalation anesthesia in order to avoid risk of complications such as malignant hyperthermia and life-threatening rhabdomyolysis. With decreasing muscle function, plaque control becomes more difficult and leads to gingivitis. Especially, the open-mouth posture worsens gingivitis and can leads to malocclusions and problems in swallowing. Regular and periodic dental care is essential for maintaining oral health for patients with MD.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.1
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• pp.27-35
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• 2016

The present study aimed to assess the perception of a child's primary caregiver on the oral health-related quality of life (OHRQoL) of dental treatment under general anesthesia (GA) or intravenous sedation (IV-SED) in pediatric dental patients. Self-administered questionnaires were completed before dental treatment under GA or IV-SED by 52 primary caregivers of healthy pediatric patients (10 years old or younger), and 43 (84%) of these caregivers completed the same questionnaires within 6 months after treatment. The Korean version of Child Oral Health Impact Profile (COHIP) and the Family Impact Scale (FIS) were used to assess OHRQoL in the questionnaires. The scores of COHIP and FIS improved after dental treatment. Demographic variables such as gender did not affect the improvement of COHIP and FIS, and age did not affect that of COHIP. However, baseline FIS score of younger patients was better than that of older patients before dental treatment. Regardless of the treatment variables, all COHIP and FIS scores were improved after dental treatment. COHIP score improved more in cases with pulp treatments compared to those without the treatments. On the other hand, FIS score improved less in cases with posterior stainless steel crown restorations compared to those without them. Anterior esthetic restorations and anterior teeth extractions did not affect the degree of improvement. Based on the primary caregiver's perceptions, the OHRQoL of healthy pediatric patients was improved by dental treatment under GA or IV-SED.