• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.32-37
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• 2016

Purpose: To determine the anatomical characteristic of C-shaped canal systems in Korean mandibular 2nd molars by cone beam computed tomography (CBCT). Materials and Methods: The 824 CBCT images were evaluated. These patients were taken CBCT for the diagnosis and treatment of dental implantation on 2013. The 711 mandibular 2nd molars were examined. The configuration of root canal systems were classified according to modified Melton's classifications. Results: Of the 711 mandibular 2nd molars, 21.5% had C-shaped canal systems. This prevalence did not differ with tooth position. Most of the C-shaped canals with bilateral molars were symmetrical. Of the C-shaped canal, the most common configuration Type were Melton's Type I (89%) in the orifice level and Melton's III (83.8%) in the apical level. The prevalence of C-shaped canal was higher in female (25%) than male (13.9%) (P < 0.05). Conclusion: A high prevalence of C-shaped canals were observed in Korean mandibular 2nd molars. For successful C-shaped root canal treatment, the comprehension of root canal systems was important.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.289-294
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• 2003

This study aimed to determine of osseointegration following dental implantation in the dog mandible using bone scintigraphy. Five mongrel dogs, weighing approximately 8.5 kg and averaging 1.8 years of age, without active periodontal disease were used. During the entire study period, all dogs were fed a soft commercial diet and water ad libitum to minimize functional loading of the implant. Titanium alloy implant systems 10 mm in length and 4 mm in diameter were chosen for insertion. Twelve weeks prior to implantation, the second and third left mandibular premolars in each dog were extracted for the dental implant insertion. Before the dental implantation procedures and 0, 4, 8, and 12 weeks after the insertions, clinical observation, radiography and bone scintigraphy were conducted. The scintigraphy was obtained using a large field of view gamma camera equipped with a paralled-hole, low-energy collimator about 3 hours after intravenous injection of Tc-99m-MDP (8 mCi/dog) to the dogs. There were not inflammation sign after insertion of dental implants on the mandible in dogs. Implants were slightly movable at the first and fourth weeks, and there was no mobility after 8 weeks. Twelve weeks after dental implantation, the bone uptake scintigraphy of peri-implant bone was similar to that of normal alveolar bone, indicating that peri-implant bone was completely regenerated by new bone. In conclusion, we recommend stable implant fixation with alveolar bone for the accurate and safe repair of teeth loot due to decacy, trauma or peridontal disease. Titanium alloy implants were optimal due to their biocompatibility.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.308-320
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• 2006

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.161-169
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• 2011

Longitudinal serial cephalometric films in the every second year from fifty girls were used for the analysis of growth pattern of maxillary alveolar bone (MAE). Six parameters regarding MAB height were measured and were compared with stature and chronological age. Descriptive analysis. correlation coefficient test and linear regression analysis were done for the statistical analyses. 1. The height of MAE increased until 14 years although growth velocity was gradually decreased. which was different with stature growth pattern. 2. The correlation coefficients between chronological age and MAB height were high and had no statistical differences with those of stature and MAB height. In addition. the correlation coefficients between chronological age groups within each parameter of MAB were very high. 3. The growth amount of MAB could be predicted using linear regression analysis on the basis of chronological age data. The growth pattern between MAE and statue was quite different because of the growth pattern difference between skeletal and neuronal system. Therefore. growth pattern of Korean MAB must be considered in dental treatment of youth. Also. close relationship between chronological age and MAB height would be useful when clinicians want to predict growth amount of MAE for the dental implant treatment.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.22 no.1
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• pp.30-46
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• 2013

Porcelain fused to metal crown has been used mostly over the last 50 years for restorations in dentistry. However, the patients' awareness of aesthetic aspect, biocompatibility and the problems such as an allergy to metals led to the growing interest in the 'metal free restoration'. In particular, the price of the precious metals that have been mainly used to date has risen drastically, which made them impossible to play their role as oral restorative materials anymore, and in addition, the PFM restoration has intrinsic problems of chipping and fracture. Therefore, the CAD/CAM has been drawing more attention than ever due to the popular needs for the material that is more aesthetic and stronger for restoration of the molar implant. Considerations in carrying out the full zirconia restoration are as follows: 1) strength, 2) combination work, 3) light penetrability, 4) treatment of cracks, 5) the color reproducibility of the block, 6) the abrasivity of antagonistic tooth, 7) low temperature degradation. In this presentation, the color reproducibility of the block will be discussed. One of the biggest reasons for avoiding the full zirconia restoration is that it is difficult to reproduce the natural color compared to the conventional PFM restoration. Thus, many clinicians show reluctance due to the exposure of the ugly block when the coloring on the surface is removed after occlusal adjustment. From the experience of using blocks by Zirkonzahn for more than 4 years, it is considered that these problems can be addressed to some degrees. Accordingly, how to make restorations that are well in harmony with surrounding prosthesis or natural teeth will be discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.2
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• pp.142-149
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• 2008

The purpose of this study was to evaluate histomorphometrically a toothash - plaster of Paris mixture associated with collagen membrane ($Bio-Gide^{(R)}$), regarding new bone formation in the peri-implantitis defects in dogs. Three mandibular molars were removed from 1-year-old mongrel dogs. After 2 months of healing, 2 titanium implants with sandblasted with large grit and acid etched (SLA) surface were installed in each side of the mandible. Experimental peri-implantitis was induced with ligatures after successful osseointegration. Ligatures were removed after identification of bone defect beneath the level of 5th thread of fixture on radiographic image. The mucoperiosteal flaps were elevated and the contaminated fixtures were treated with chlorhexidine and saline. The bone defects were assigned to one of the following treatments: no guided bone regeneration (GBR) procedure (group 1), GBR with Bio-$Oss^{(R)}$ and Bio-$Gide^{(R)}$ (group 2), or GBR with toothash - plaster of Paris mixture (TPM) and Bio-$Gide^{(R)}$ (group 3). The dogs were sacrificed after 8 or 16 months. The mean percentages of new bone formation within the limits of the 5 most coronal threads were $17.83{\pm}10.69$ (8 weeks) and $20.13{\pm}13.65$ (16 weeks) in group 1, $34.25{\pm}13.32$ (8 weeks) and $36.33{\pm}14.21$ (16 weeks) in group 2, and $46.33{\pm}18.39$ (8 weeks) and $48.00{\pm}17.78$ (16 weeks) in group 3, respectively. The present study confirmed statistically considerable new bone formation within the threads in group 3 compared with group 1 at 8 and 16 weeks (P<0.05). Although, data analysis did not reveal significant differences between group 2 and 3, the latter showed better results during the period of 8 or 16 weeks. Our findings support the effectiveness of TPM as a GBR material in the treatment of peri-implantitis bone defect.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.661-671
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• 2006

The purpose of this study was to evaluate cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with ITI SLA (sand-blasted, large-grit, acid-etched) implant system and compare the CSR between first and second molar. The findings from the results were as follows; 1. Total of 158 implants were inserted into 147 patients. 68 patients were males, 79 patients were females and their mean age was 47.8 years. 98 implants were placed in first molar area and 60 implants were placed in second molar area. In terms of diameter, implants with wide diameter over 4.8mm dominated (91.1%). Implants with length over lOmm were used (96.2%). 2, In the two cases, there was a slight transient numbness which recovered within 1-2 months. Nine SynOcta screw type abutments demonstrated screw loosening, There were ten cases of crown fallen-out from decementation. 3. Only one failed out of 158 implants. The CSR was 99.4%. The CSRs for first molar and second molar were 99% and 100%, respectively. From the results, it was concluded that single tooth replacement implant in the mandibular posterior area, might be considered as the effective treatment modality comparable to the conventional crown and bridge.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.202-208
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• 2015

The aim of this retrospective study was to evaluate the relationship between periodontal health condition and the results of a new method such as Cariview which could evaluate the acidity of dental biofilms. Fifty four subjects more than 20 years old were selected for the candidates of this study. The periodontal health conditions of the candidates were divided into 4 groups according to the assessment of X-ray and Quantitative Light-induced Fluorescence-Digital (QLF-D; Inspektor Research Systems BV) images; gingivitis, slight periodontitis, moderate periodontitis, severe periodontitis. The biofilm acidogenicity of each subject was examined using Cariview (All in ONE BIO) according to manufacturer's instruction, and the Cariview score was calculated. The mean differences of Cariview score between 4 groups of periodontal health condition were examined by ANCOVA test with the covariance of decayed, missing, and filled teeth (DMFT) index. As a result, the mean Cariview score was different, however it was not significantly different from the 4 groups (p=0.12). The mean score was the lowest in the gingivitis group ($40.54{\pm}11.01$), and the highest in slight periodontitis group ($57.26{\pm}20.51$). In conclusion, the significant mean differences were not confirmed in Cariview score according to the periodontal health condition.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.299-304
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• 2021

Purpose. The purpose of the present study was to investigate the effects of image matching experience of operators on the accuracy and working time of image registration between radiographic and optical scan images. Materials and methods. Computed tomography and optical scan of a dentate dental arch were obtained. Image matching between the computed tomography and the optical scan (IDC S1, Amann Girrbach, Koblah, Austria) was performed using the point-based automatic registration method in planning software programs (Implant Studio, 3Shape, Copenhagen, Denmark) using two different experience conditions on image registration: experienced group and inexperienced group (n = 15 per group, N = 30). The accuracy of image registration in each group was evaluated by measuring linear discrepancies between matched images, and working time was recorded. Independent t test was used to statistically analyze the result data (α = .05). Results. In the linear deviation, no statistically significant difference was found between the experienced and inexperienced groups. Meanwhile, the working time for image registration was significantly shorter in the experienced group than in the inexperienced group (P = .007). Conclusion. Difference in the image matching experience may not influence the accuracy of image registration of optical scan to computed tomography when the point-based automatic registration was used, but affect the working time for the image registration.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.29 no.2
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• pp.103-117
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• 2020

A beautiful smile has a great impact on the quality of life. It gives you confidence, and makes you function with a positive attitude, which will eventually bring the joy and happiness to daily lives. As dental practitioners, our mission is to bring back the bright smile of the people who come to see us. Restoring masticatory function is one thing but one should always remember that the esthetics should always come first in any kind of restorative procedures. When treating complex rehabilitation cases, treatment planning is probably the most important step before you start any dental procedures. Obviously, esthetics should be the ultimate goal of the treatment and one should approach a case step by step to achieve an optimal result. For the past few years, "digital smile design" has been introduced in the field of dentistry. It can be applied by using various methods and tools. In this article, a very basic form of 2-dimensional digital smile designing was utilized to treat a complete mouth rehabilitation case. We will discuss how the DSD concept can be applied to your daily practice with a simple photograph and photoshop.