• Imaging Science in Dentistry
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• v.46 no.1
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• pp.9-16
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• 2016

Purpose: To evaluate the upper airway dimensions of obstructive sleep apnea (OSA) and control subjects using a cone-beam computed tomography (CBCT) unit commonly applied in clinical practice in order to assess airway dimensions in the same fashion as that routinely employed in a clinical setting. Materials and Methods: This was a retrospective analysis utilizing existing CBCT scans to evaluate the dimensions of the upper airway in OSA and control subjects. The CBCT data of sixteen OSA and sixteen control subjects were compared. The average area, average volume, total volume, and total length of the upper airway were computed. Width and anterior-posterior (AP) measurements were obtained on the smallest axial slice. Results: OSA subjects had a significantly smaller average airway area, average airway volume, total airway volume, and mean airway width. OSA subjects had a significantly larger airway length measurement. The mean A-P distance was not significantly different between groups. Conclusion: OSA subjects have a smaller upper airway compared to controls with the exception of airway length. The lack of a significant difference in the mean A-P distance may indicate that patient position during imaging (upright vs. supine) can affect this measurement. Comparison of this study with a future prospective study design will allow for validation of these results.

• Journal of dental hygiene science
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• v.20 no.1
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• pp.34-43
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• 2020

Background: The number and curriculum of dental hygienists in Korea have dramatically increased. Controversies have since resulted from insufficient job descriptions of the work performed by a dental hygienist. A dentist's perception was examined to legally reflect the actual work of dental hygienists. Methods: Four hundred and nineteen dentists were surveyed about the duties of a dental hygienist. Their views on the career and availability of each job were examined. The duties of the dental hygienist include 13 items in dental treatment preparation, 14 items of radiography, 21 items of preventive dentistry, 6 items of periodontal treatment, 12 items of oral medicine, 12 items of conservative dentistry, 8 items of prosthetics, 10 items of orthodontics, 7 items of oral and maxillofacial surgery, 6 items of implantation, 6 items of impression taking and model fabrication, 5 items of anesthesia and injection, 11 items of management and administrative, and 3 items of self-development. Results: Most of the duties were doable by a dental hygienist. Many dentists reported that managing implants, oral hygiene of special patients, some duties in oral medicine, teeth brightening, making temporary crowns, making individual trays, selecting shades, ligaturing, and precision impressions need ≥3 years of experience. Duties perceived by dentists not to be performed by dental hygienists were reading radiographs (55.4%), suture and stitch out (48.0%), intramuscular injection (36.0%), root planning (27.2%), cementation and removal of prostheses (23.2%), and examining pulp vitality (22.0%). Conclusion: Current laws are to be revised to include, the care provided by dental hygienists and under a physician's supervision. Flexibility is also needed to cope with rapidly changing dental technology.

• Korean Journal of Cleft Lip And Palate
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• v.4 no.2
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• pp.19-27
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• 2001

This study was performed to determine the prevalence of hypodontia and hyperdontia of permanent teeth among Korean schoolchildren, and to compare differences in the prevalence between Korea, other country, and other ethnic groups. The sample consisted of 346 girls aged 6.9～0.3 yr and 375 boys aged 6.8～0.4 yr on whom a panoramic radiograph was taken at Yeonchun-Gun community in Korea. The prevalence of congenitally missing teeth (third molars excluded) was 6.7% in boys and somewhat higher, 9.5% in girls, and 8.0% for both sexes combined. On the average, number of missing teeth per affected child was 1.9 teeth. The most commonly congenitally missing teeth were the mandibular second premolar (32.7%), followed by the mandibular incisor (28.7%), the maxillary second premolar (16.7%), and the maxillary lateral incisors (10.2%). The prevalence of supernumerary teeth was 2.1 % in boys, 1.4% in girls, and 1.8% for both sexes combined. The most common supernumerary teeth were the mesiodens (76.9%), followed by the supernumerary premolar (23.1 %). The affected male-female ratio was 1.6: 1.0. The prevalence of congenital missing teeth in this study was similar to in studies of Japanese, Danish, American and German. The frequency of hyperdontia was lower in this study than in studies of Chinese children, Japanese and American.

• The Journal of Advanced Prosthodontics
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• v.7 no.6
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• pp.423-430
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• 2015

PURPOSE. To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth $Ankylos^{(R)}$ implants. MATERIALS AND METHODS. This was a retrospective clinical study that analyzed 450 single $Ankylos^{(R)}$ implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position. RESULTS. The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05). CONCLUSION. The $Ankylos^{(R)}$ implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.160-165
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• 2015

PURPOSE. In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS. Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous$^{(R)}$; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at $30^{\circ}$ in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. RESULTS. Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. CONCLUSION. Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.27-36
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• 2009

Purpose: The stability of periodontal condition and marginal bone level were important to achieve long-term success of dental implant treatment. The aim of this study was to evaluate periodontal conditions and marginal bone loss around 67 GSII(OSSTEM, Seoul, Korea) dental implants with dual-microthread at the neck portion, 1 year after prosthetic loading. Materials and methods: Sixty-seven GS II dental implants in 27 patients(mean age; $47.4{\pm}14.0$ years) who received implant treatments at Pusan National University Hospital, were included in this study. Thirteen US II(OSSTEM, Seoul, Korea) implants with smooth neck design were selected for the control group. Periodontal and radiographic evaluations were carried out at baseline, 6 months and 12 months after prosthetic loading. Results: In the GS II group, plaque index(PI), gingival index(GI) and probing depth(PD) increased as time passed. In the US II group, GI and PD increased. Although marginal bone level was lower in the US II group in all evaluation periods, the changes between the periods were not statistically significant(p>0.05). In each period, periodontal parameters were not statistically significant between groups. Conclusion: One year after prosthetic loading, GS II and US II dental implants showed similar periodontal conditions and marginal bone response, and were within the criteria of success.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.104-109
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• 2013

PURPOSE. Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiberreinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS. Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at $38^{\circ}C$). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at $37^{\circ}C$. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukey's HSD (${\alpha}$=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS. Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiberreinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION. The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.3
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• pp.23-39
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• 2014

Objective : This review aims at analyzing Complementary and Alternative Medicine (CAM) therapies, using for oral health to know current use of CAM in dental area by analyzing randomized controlled clinical trials (RCTs). Method : We searched the following 6 electronic databases until 1 July 2014. : Pubmed, Medline, Embase, Allied and Complementary Medicine Database(AMED), Cumulative Index to Nursing and Allied Health Literature(CINAHL), the Cochrane Library. We included parallel RCTs and cross-over RCTs that assessed the efficacy of CAM regardless of blinding and language. Results : A total of 154 RCT articles were included. There were 2-arm parallel study design(69.5%), 3-arm parallel study design(20.8%), 4-arm parallel study design(4.5%) and Cross-over design(5.2%). Complementary and alternative medicine RCTs in oral health tend to increase in the early-2000s and in the mid-2010s. In addition, 154 citations were classified according to diseases and interventions that categorized Natural Products studies(68.2%), Mind and Body Practices studies(31.8%). We classified in detail that vitamin and mineral therapies(29.9%), dietary supplements(24.7%), acupuncture(23.3%), Herbal medicine(13.6%), homeopathy (2.6%), energy therapies(2.6%), Massage(1.9%), biofeedback(0.6%), traditional medicine(0.6%). Conclusion : Increasing publications and diverse interventions regarding CAM for oral health is observed by analyzing RCTs from the literature review. Further studies are needed to be performed as systematic reviews to verify their effectiveness and the research to inquire into side effect.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.4
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• pp.593-607
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• 1994

The purpose of this study is to evaluate the effect of the bone morphogenetic protein, bone matrix gelatin and collagen matrix on the amount and shape of generating new bone adjacent to the implant. Implants were inserted in the mandible of adult dogs at 2 months after teeth extraction. Artificial bony defects, 3mm in width and 4mm in depth were made at the mesial and distal side of implant. Experimental groups were divided into three groups ; Group 1 : Defects filled with collagen matrix and bone morphogenetic protein, Group 2 : Defects filled with bone matrix gelatin. Control group : Defects filled with only collagen matrix. After implantation, the animals were sacrificed at 1,3,5 and 10 weeks for light microscopic examination. For the fluorescent microscopic examination. each tertracycline Hcl and calcein were injected at 1, 3, 5, 8 and 10 weeks after implantation. The results obtained were as follows : 1. The molecular weight of bovine BMP was about 18,100 by hydroxyapatite chromatography. 2. Osseointegration was observed in experimental groups 1 & 2, and BMG and BMP had an excellent bone forming capability as a filling materials to the repair of the bone defects. 3. The degree of healing of bone defect area, the experimental group 1 showed more prominent bone formation than control group, and the control group showed fibrous connective tissue between the implant and the bone. 4. In the fluorescent microscopic findings, bone remodelling was observed regenerative lamellar bone at defect area in experimental group 1, and partial remodelling in experimental group 2, In the control group, fibrous connective tissue was observed between the implant and bone surface and sign of remodelling was not apperaed. Above results suggest that BMP has rapid osteoinductive property and can be used clinically as a bone substitute on bone defects around implants.

• The Korean Journal of Pain
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• v.26 no.2
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• pp.130-134
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• 2013

Background: The aims of this study were to analyze the anatomic variations of supraorbital foramina/notches in Koreans and to compare the results with those of previous studies examining other races. We evaluated the three-dimensional computed tomography (3D-CT) images of human faces using multidetector computed tomography (MDCT). Methods: A total of 395 adults (232 men and 163 women) were enrolled and the 3D-CT images of their faces were reviewed in this study. In this study, the data from the images included the presence, shape, width and distance from the nasion to the supraorbital foramina/notches. ANOVA was used to assess the main effects of gender and side (right or left foramen/notch), and comparisons of the means were done by paired t-test. Results: The most common shapes in Koreans were a single notch (39.5%) on the right hand side and a single foramen (42.3%) on the left hand side. The incidence of a single foramen in Koreans was high compared to other races. The mean foramen diameter was $2.34{\pm}0.78$ mm, and the mean distance from the nasion was $27.19{\pm}4.03$ mm. The mean notch diameter was $3.37{\pm}1.71$ mm, and the mean distance from the nasion was $23.42{\pm}2.45$ mm. Conclusions: This is the first study on the variations of supraorbital foramina/notches in Koreans using 3D-CT images of faces. The anatomic characteristics of the supraorbital foramina/notch will help in performing nerve blocks and maxillofacial surgery.