• Journal of Periodontal and Implant Science
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• 제48권4호
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• pp.236-250
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• 2018

Purpose: Resorption of the alveolar bone is an unavoidable consequence of tooth extraction when appropriate alveolar ridge preservation (ARP) measures are not taken. The objective of this trial was to test the hypothesis that dimensional changes in the alveolar bone after tooth extraction would be reduced by inserting an equine collagen membrane and a collagen cone to fill and seal the alveolus (as ARP), in comparison to extraction with untreated alveoli. Methods: In this randomized clinical trial, 31 patients were directly treated with the collagen material after extraction of a tooth from the maxilla (the ARP group). Twenty-nine patients served as the control group. After extraction, no further treatment (i.e., no socket preservation measures) was performed in the control group. Changes in the alveolar process immediately after extraction and after an 8 (${\pm}1$)-week healing period were evaluated 3-dimensionally. Blinded analyses were performed after superimposing the data from the digitalized impressions and surfaces generated by cone-beam computed tomography. Results: Both the ARP and control groups showed a reduction of bone in the alveolar area after tooth extraction. However, significantly less bone resorption was detected in the clinically relevant buccal region in the ARP group. The median bone reduction was 1.18 mm in the ARP group and 5.06 mm in the control group (P=0.03). Conclusions: The proposed hypothesis that inserting a combination material comprising a collagen cone and membrane would lead to a difference in alveolar bone preservation can be accepted for the clinically relevant buccal distance. In this area, implantation of the collagen material led to significantly less alveolar bone resorption. German Clinical Trials Register at www.drks.de, DRKS00004769.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.2.1-2.9
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• 2016

Background: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. Method: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. Results: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. Conclusions: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to $1200{\mu}m$ had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.

• 대한치과교정학회지
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• 제46권2호
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• pp.111-126
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• 2016

Objective: To systematically review previous studies and to assess, via a subgroup meta-analysis, the combined odds ratio (OR) of prognostic factors affecting the success of miniscrew implants (MIs) inserted into the buccal posterior region. Methods: Three electronic searches that were limited to articles on clinical human studies using MIs that were published in English prior to March 2015 were conducted. The outcome measure was the success of MIs. Patient factors included age, sex, and jaw of insertion (maxilla vs. mandible), while the MI factors included length and diameter. A meta-analysis was performed on 17 individual studies. The quality of each study was assessed for non-randomized studies and quantified using the Newcastle-Ottawa Scale. The meta-analysis outcome was a combined OR. Subgroup and sensitivity analyses based on the study design, study quality, and sample size of miniscrews implanted were performed. Results: Significantly higher success rates were revealed for MIs inserted in the maxilla, for patients ${\geq}20$ years of age, and for long MIs (${\geq}8mm$) and MIs with a large diameter (> 1.4 mm). All subgroups acquired homogeneity, and the combined OR of the prospective studies (OR, 3.67; 95% confidence interval [CI], 2.10-6.44) was significantly higher in the maxilla than that in the retrospective studies (OR, 2.10; 95% CI, 1.60-2.74). Conclusions: When a treatment plan is made, these risk factors, i.e. jaw of insertion, age, MI length, and MI diameter, should be taken into account, while sex is not critical to the success of MIs.

• 대한치과교정학회지
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• 제47권1호
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• pp.39-49
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• 2017

Objective: This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root-crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). Methods: We included 672 Korean patients (141 men and 531 women; mean age, $27.2{\pm}7.7years$) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. Results: Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. Conclusions: The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

• 지역연구
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• 제10권2호
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• pp.17-29
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• 1994

This study attempts to examine the regional distribution and the locational pattern of leisure facilities at Kangnam-gu in Seoul. For the convenience of the analysis the facilities are classified into public and private sector and then the facilities are classified into 11 types: mineral spring resort, play ground, neighborhood park, swimming pool, gymnasium, bowling, pingpong, aerobic, golf practice, health, and billiard facilities. For the purpose data was collected from statistical yearbook in 1993 and lists of registered facility at department of living physics of Kangnam-gu office. The data of the density of facilities and the opportunity of facilities per facilities type and per region are analysed with the technology of GIS. Results may be summarized as follows. First of all, correlation between the results of Location-Allocation model and the results of Interaction model is very high. Secondly, on comparing the density of facilities with the opportunity of the facility use per eleven facility types, three discrete spatial pattems are found. The mineral spring resort facility type with the highest unbalanced density and opportunity of facility use is to be found. Play ground, neighborhood park, swimming pool, gymnasium, bowling, pingpong, and aerobic facility types have the high unbalanced density and opportunity of facility use. The golf practice, health, and billiard facility types have spatially balanced density and opportunity of facility use. Thirdly, as comparing the density and the opportunity of the facility use per 'dong' administration unit, the spatial patterns of the public and the private facilities are different in density of the facility use and otherwise two are similar in the opportunity of the facility use. Fourthly, patterns of facilities users have different charateristics based on facility use time, expense, residence, and access time and four regional patterns are to be found ; user favorable, facility profitable, user balanced, and unfavorable.

• 대한치과교정학회지
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• 제38권6호
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• pp.388-396
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• 2008

본 연구의 목적은 성장이 끝난 성인 여대생들에 있어 가장 흔한 부정교합의 하나인 전치부의 crowding과 입술주위 돌출감이 자존감(self-esteem)에 미치는 영향을 알아보는 것이다. 연구를 위하여 대학에 재학중인 여자대학생 67명을 대상으로 구강검진과 두부계측방사선 사진촬영, 모형계측을 실시하여 상악전치부의 치아배열과 입술의 돌출도를 평가하였다. 또한 Rosenberg의 자존감 평가 설문조사문항을 이용하여 이들의 자존감을 평가한 후 전치부의 치아배열, 입술주위 돌출도와 자존감 간에 어떠한 관계가 있는지 통계처리 하였다. 실험결과, 입술의 돌출을 가졌거나 전치부의 치아배열이 고르지 못한 학생들은 치아배열이 고르고 돌출되지 않은 안모를 가진 학생들에 비하여 유의하게 낮은 자존감을 보여주었다. 부정교합이 심리적으로 미치는 부정적 영향력에 관하여 더욱 체계적인 연구와 교육, 홍보가 필요하다고 생각한다.

• Journal of Periodontal and Implant Science
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• 제46권4호
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• pp.234-243
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• 2016

Purpose: Immediate loading of dental implants has been proved to be feasible in partially edentulous jaws. The purpose of this retrospective investigation was to assess the feasibility of immediately loading dental implants in fully edentulous jaws. Methods: A total of 24 patients aged between 53 and 89 years received a total of 154 implants in their edentulous maxillae or mandibles. Among the implants, 45 were set in fresh extracted sockets and 109 in consolidated alveolar bones. The implants were provisionally managed with chair-side made provisional resin bridges and exposed to immediate loading. Implants were followed up for 1-8 years, including radiographic imaging. Marginal bone levels were evaluated based on radiographic imaging. Results: A total of 148 out of the 154 implants survived over the follow-up period of 1 to 8 years, giving a survival rate of 96%. The time or region of the implantation, the pre-implant augmentation, and the length and diameter of the implants had no statistically significant influence on the survival or the success rate. The marginal bone level remained stable with only minimal loss of 0.3 mm after 60 months of loading. Conclusions: Within the limitations of this study, immediate loading is feasible for dental implants in edentulous jaws.

• 대한치과교정학회지
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• 제44권6호
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• pp.294-303
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• 2014

Objective: The purpose of this study was to examine whether orthodontic treatment experience affects the individual's perception of smile esthetics and to evaluate differences among orthodontically treated laypersons, non-treated laypersons, and dentists by using computerized image alterations. Methods: A photograph of a woman's smile was digitally altered using a software image editing program. The alterations involved gingival margin height, crown width and length, incisal plane canting, and dental midline of the maxillary anterior teeth. Three groups of raters (orthodontically treated laypersons, non-treated laypersons, and dentists) evaluated the original and altered images using a visual analog scale. Results: The threshold for detecting changes in maxillary central incisor gingival margin height among laypersons was 1.5 mm; the threshold of dentists, who were more perceptive, was 1.0 mm. For maxillary lateral incisor crown width and height, the threshold of all three groups was 3.0 mm. Canting of the incisal plane was perceived when the canting was 3.0 mm among non-treated laypersons, 2.0 mm among treated laypersons, and 1.0 mm among dentists. Non-treated laypersons could not perceive dental midline shifts; however, treated laypersons and dentists perceived them when the shift was ${\geq}3.0mm$. Conclusions: Laypersons with and without orthodontic treatment experience and dentists have different perceptions of smile esthetics. Orthodontically treated laypersons were more critical than non-treated laypersons regarding incisal plane canting and dental midline shifts. Based on these findings, it is suggested that orthodontic treatment experience improved the esthetic perceptions of laypersons.

• The Journal of Advanced Prosthodontics
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• 제7권2호
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• pp.151-159
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• 2015

PURPOSE. To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS. A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non- quantitatively. RESULTS. All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION. The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

• 가정의학회지
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• 제39권6호
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• pp.355-359
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• 2018

Background: Body image is associated with the perception of people on themselves. Influencing factors are generated internally and/or externally. The most common issue pertaining to body image is body weight and weight loss. This study aimed to determine the association between body weight perception and weight loss practices among college students. Methods: A cross-sectional study was conducted involving 297 college students from private nursing colleges in the state of Kelantan, Malaysia. A self-administered questionnaire was used to assess sociodemographic characteristics, body weight perception, and weight loss methods. Weight and height were measured, and body mass index (BMI) was calculated based on weight and height measurement. The World Health Organization BMI cutoffs were applied in the study. Results: More than half (54.2%) of college students perceived their weight correctly as per actual measured BMI. A total of 51.5% of participants had tried various methods to reduce their weight. Body weight perception is associated with weight loss practices (odds ratio, 0.31; 95% confidence interval, 0.19-0.50; P<0.001) adjusted for sex, marital status, and status of having obese family members. Those who had correct body weight perception were less likely to engage in weight loss practice. Food intake restriction (42.4%) is the most popular weight reduction method among students in nursing colleges. Over a quarter of the participants chose physical exercise (25.3%) to reduce their weight, and a small number engaged in unhealthy weight loss practices. Conclusion: Body weight perception is an important factor that influences the practice to reduce weight especially among young adult group and college students.