• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.4
• /
• pp.512-518
• /
• 2010

The impaction of the maxillary permanent incisor is a common clinical problem and is mostly found at the "labial to the alveolar process." Surgical exposure and orthodontic treatment with fixed orthodontic appliances can be considered if normal eruption of the labillay impacted tooth is not expected. Surgical exposure of the impacted tooth, that is usually under the attached gingiva or is surrounded by alveolar bone through gingivectomy and removal of alveolar bone, may give a rise to complications such as diminution in the width of the attached gingiva, inflammation of the gingiva, and the loss of marginal alveolar bone. Therefore, closed eruption technique, which includes surgical exposure and orthodontic treatment with fixed orthodontic appliances followed by repositioning of surgical flap, is preferred. However, apically repositioned flap of the impacted tooth, which is beneath the movable submucosal area or is above the alveolar crestal area, can prevent unwanted exposures and facilitate successful tooth eruption. In this report, we described esthetic results of three patients with unerupted maxillary permanent incisor who were performed with an apically positioned flap without the loss of attached gingiva.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.47 no.2
• /
• pp.205-212
• /
• 2020

The purpose of this study is to evaluate the validity of primary anterior zirconia crown made with Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) technology by analyzing fracture strength and translucency parameter. Zirconia crown was designed with CAD software, using 3D scanned data of #61 tooth model. Crown fabrication was performed with CAM machine using zirconia block. Zirconia crowns were divided into 3 groups according to thickness(0.3, 0.5, and 0.7 mm), and fracture strength was compared with 1.0 mm thickness of resin strip crown. The compressive force was applied with universal testing machine at 30° along the incisal edge at increments of 1 mm/min. For translucency evaluation, 0.3, 0.5, and 0.7 mm thickness of zirconia specimens were fabricated and translucency was measured with spectrophotometer. Among zirconia groups, there was a significant increase in fracture strength as thickness increased (p < 0.05). The fracture strength of zirconia crown was significantly higher than resin strip crown in all groups (p < 0.05). Translucency parameter was highest in 0.3 mm group, and significantly decreased as thickness increased to 0.5 and 0.7 mm (p < 0.05). Thin primary anterior zirconia crown can be designed and fabricated according to individual needs by using CAD/CAM. Restoration with thin crown would reduce the amount of tooth reduction, risk of pulp exposure, and make more esthetic restoration possible.

• Journal of Technologic Dentistry
• /
• v.31 no.2
• /
• pp.45-52
• /
• 2009

Esthetic restorations have been widely used in dental practice, although many studies have focused on the development and improvement of all ceramic restorations. The success of esthetic restorations depends primarily on an optimal bond strength between various veneered ceramics and core materials for esthetic restorations. The purpose of this study was to compare the shear bond strength between various veneered ceramics and core materials for esthetic restorations. 30 metal cores and 20 zirconia cores were fabricated and divided into five groups according to veneered ceramic materials such as Creation porcelain powder, Cercon Ceram Kiss, and IPS e.max ZirPress. Thirty spacimens were prepared using Creation porcelain powder, veneered 3mm height and 3mm in diameter, over the metal cores (n=10). Twenty specimens were prepared using Cercon Ceram Kiss and Zirpress, veneered 3mm height and 3mm in diameter, over the zirconia cores (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 1mm/min. Ultimate shear bond strength data were analyzed with One-way ANOVA and the Scheffe's test (p=.05). Within the limits of this study, the following conclusions were drawn: The mean shear bond strengths (MPa) were: 18.44 for Uni metal VH/Creation (NCUC); 18.72 for Heraenium/Creation (NCHC); 16.23 for Wirobond C/Creation (NCWC); 13.88 for Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss (ZS110P); 14.61 for Zirconia core/No surface treatment/IPS e.max ZirPress (ZNTH). The mean shear bond strength for NCUC (Uni metal VH/Creation), NCHC (Heraenium/Creation) and NCWC (Wirobond C/Creation) were significantly superior to ZS110P (Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss) and ZNTH(Zirconia core/No surface treatment/IPS e.max ZirPress) (p<0.05).

• The Journal of Korean Academy of Prosthodontics
• /
• v.55 no.4
• /
• pp.427-435
• /
• 2017

The most important factor in the treatment of fully edentulous patients using implants is the shape of the definitive prosthesis. After the shape of the definitive prosthesis is determined, residual bone analysis and selection of the implant type, number and position should be followed. In this case, for restoration of an edentulous patient fully implanted (except the maxillary right lateral incisor) without considering definitive prosthesis, facial esthetics and possibility of fixed type prosthesis were evaluated using complete denture. It was determined that the fixed type prosthesis was possible. Implants that could not be used for the definitive prosthesis were excluded from the treatment plan and fixed type provisional restorations were fabricated. After four months of provisional restorations, the patient showed stable occlusion and esthetic satisfaction. Definitive prosthesis was made of zirconia using CAD/CAM (computer aided design and computer aided manufacturing). The results were satisfactory during the 3 months of follow-up period after termination of treatment.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.41 no.1
• /
• pp.72-79
• /
• 2014

Cleft lip and palate(CLP) is one of the most common craniofacial deformities that requires systemic management involving a multidisciplinary team approach. Although there has been great improvement in the field of cleft surgery, surgical approach alone cannot resolve the various problems in treating cleft lip and palate. Hence the need for presurgical treatment was appreciated and especially, the concept of presurgical nasoalveolar molding was applied to treat unilateral and bilateral cleft lip and palate patients. Presurgical nasoalveolar molding(PNAM) of unilateral cleft mainly aims to recover nasal symmetry while the objectives of pre-surgical nasoalveolar molding in the bilateral cleft are to elongate the columella, to erect the tip of nose, and to reposition the forward displaced premaxillary region. This report covers the case of fraternal twins diagnosed with bilateral cleft. Retraction of the premaxillary region and nasoalveolar molding were conducted for 70 days until cheiloplasty, using elastic bands and nasoalveolar molding appliances. After cheiloplasty, there had been improvements in the length of columella and the position of forward-displaced premaxilla for both patients compared to their initial states. The esthetics was also satisfactory for both the surgery and the parents. In order to maximize the efficacy of the appliance, three components should be in balance; patients' adaptation to the appliance, parents' cooperation and proper selection and careful adjustment of the appliance by the dentist.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.4
• /
• pp.658-665
• /
• 2007

Oligodontia is defined as the congenital absence of six or more teeth in dentition, excluding the third molars. The prevalence of congenital missing teeth is about 1.6 to 9.6% of population and the prevalence of oligidontia is about 0.08 to 1.1%. The mandibular second premolar is the most frequently absent after the third molar, followed by the maxillary lateral incisor and upper second premolar. Females seem to be affected slightly more than males. Oligodontia may occur either in isolation, or as a part of a syndrome such as ectodermal dysplasia. Different causes are possible for oligodontia: physical obstruction or distruction of the dental lamina, space limitation, functional abnormalities of the dental epithelium, failure of induction of the underlying mesenchyme, chemotherapy, radiotherapy or genetic factor. Because oligodontia would result in esthetic and functional problems, such as facial asymmetry or occlusal disharmony, early diagnosis from clinical and radiographic examination was necessary. And appropriate treatment plan should be followed. This case report was about oral conditions and treatment of the oligodontia patients who have no specific systemic disease.

• The korean journal of orthodontics
• /
• v.31 no.3 s.86
• /
• pp.347-355
• /
• 2001

Maxillary and mandibular anterior dental arches often have the problems of occlusal relation and esthetics by malformations of teeth, congenital missing, et at. Though the clinician usually use the anterior ratio to overcome this problems, he has the limitation of a direct application this ratio to the prediction of anterior occlusal relationship by the change of anterior ratio as dental arch form, intercanine width, segment depth and arch perimeter. So this study examine maxillary and mandibular anterior dental arch forms by least square method using Korean normal occlusion models(man : 20 casts, woman : 20 casts). Maxillary and mandibular anterior dental arches of Korean normal occlusion models are curve fitted to polynomial function, beta function, hyperbolic cosine function in order. And this accuracy of curve fitting is constant regardless of man/woman and maxilla/mandible. The relationships between intercanine width, segment depth, and arch perimeter based on this owe fitted dental arch form are acquired. This relationships will give the prediction of anterior dental arch form and the information of more accurate anterior ratio according to intercanine width.

• The korean journal of orthodontics
• /
• v.28 no.3 s.68
• /
• pp.431-440
• /
• 1998

While periodontal disease results in the extrusion of upper incisors with interdental spacing in adult patient, the intrusive movement should be executed for the rehabilitation in terms of esthetics and function. The present study was peformed to investigate the periodontal response following orthodontic intrusion of teeth with infrabony pocket. Bone defect and periodontal disease were produced adjacent to the both maxillary second lateral incisors in four adult dogs. Four weeks later, a flap operation was performed to eliminate inflammation and a reference notch was made on the root surface at the level of bottom of each defect. Two weeks after periodontal surgery, 4 weeks of intrusion and subsequent another 4 weeks of retention was executed on the right side of incisors while left incisors served as the control. Through the histologic analysis, following results were obtained. 1. Histologic section of control side showed the reduction of pocket depth after flap operation. However, the status of long junctional epithelium was observed while new connective tissue attachment occurred in a small area adjacent newly formed cementum 2. Epithelial attachment was less around the intruded incisor while new connective tissue attachment was much more compared to the control side. 3. Plenty of cells were observed in the connective tissue around the reference notch of the intruded incisor and the degree of the new cementum formation was higher in the intruded incisor than the control. The results of the present study suggested that an orthodontic intrusion of periodontally involved and extruded incisors could be carried out with a desirable periodontal response, provided that inflammation is under control.

• The korean journal of orthodontics
• /
• v.30 no.3 s.80
• /
• pp.355-365
• /
• 2000

The treatment plan for orthognathic surgery must be based on accurate predictions, and this can be produced the most esthetic results. Treatment of prognathic mandible in adult is usually orthognathic surgery using mandible set back, but mandible with retruded chin point is needed additional chin augmentation. In this case, the directions between mandible and chin point are different therefore, the prediction of soft tissue reactions must be modified. In this study, we materialize the patients who was taken orthognathic surgery due to prognathic mandible, 11each(Group A) was taken only Bilateral Sagittal Sprit Ramus Osteotomy (BSSRO), 9each(Group B) was taken additional advancement genioplasty. The lateral cephalometric radiography taken 8 months later after orthognathic surgery by this patients were used. The results of this study were as follows : 1. The profile of lips was favorable after surgery due to upper lip to I-line became prominent and lower lip tc E-line was retruded. 2. In both group, upper lip moved posteriorly and nasolabial angle was increased. 3. The ratio of the soft tissue profile change in POGs point to skeletal B point movement was $84\%$ in group A and $66\%$ in group B, and there was statistical significance between group A and group B. 4. Vertical movement of hard tissue points is decreased in group A.

• The korean journal of orthodontics
• /
• v.32 no.2 s.91
• /
• pp.143-153
• /
• 2002

The bonded orthodontic retainer constructed from composite and multistrand orthodontic wire provides an esthetic and efficient system for maintained retention. This study was designed to measure shear bond strength of bonded retainers and to suggest a optimal combination of a multistrand wire and bonding method used when bonded retainer was fabricated. 160 sound maxillary and mandibular premolars were used for 80 test samples. After Uniformizing bonding area, length of wire, and thickness of composite, multistrand wire was bonded to fabricated a bonded retainer by direct or indirect bonding method. Shear bond strength and extension length of each sample were measured by a universal testing machine. The results of this study were as follows : 1. In vitro shear bond testing found 6-stranded, 0.0155 inch wires to have the largest shear bond strength and 3-stranded, 0.0195 inch wires to have the least shear bond strength. But, These difference was not statistically significant(p<0.05). 2. In vitro extension testing found 3-stranded, 0.0155 inch wires to have the largest extension length and 3-stranded, 0.0195 inch wires to have the least extension length(p<0.05). The larger diameter wire was used, the larger extension length was shown. But, the strand of wire is not related to the extension length of wire. 3. In comparison with direct bonding method, larger shear bond strength and extension length was shown in indirect bonding method(p<0.05).