• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.368-373
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• 2010

The incisors function as instruments for biting and cutting food during mastication. They also support the lips and face and maintain vertical dimension. In addition, they contribute to overall normal arch appearance. They play important role during the articulation of speech and assist in guiding jaw closure. Extraction and space maintenance are the most common treatment for a tooth with poor prognosis. However, in the mixed dentition, extraction of the upper permanent incisors results in many complications, such as resorption of alveolar bone, poor esthetics, pronunciation, and mastication. Considering these various roles of incisors in oral cavity, approach for traumatized incisors, even the ones with poor prognosis, should be considered first prior to simple extraction. The dentist must take into account the age of the patient, growth potential, occlusion, oral hygiene status, economic status and motivation towards dental health in addition to patient compliance. In this case, although the prognosis was predicted to be unfavorable due to short root and mobility, we could save the central incisor using conservative treatment, reposition by orthodontic appliance instead of extraction.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.333-339
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• 2015

The study was intended to investigate the factors affecting dental caries in adults. To that end, adults aged 19 years and older among 10,113 subjects who completed the health-related questionnaire, medical examination and nutrition surveys in the first year (2013) of the 6th Korea National Health and Nutritional Examination Survey, and 4,843 subjects categorized as patients with permanent teeth caries were included in the final analysis. The prevalence of dental caries in line with socio-economic aspects was found to be higher in men than in women. In view of education, the prevalence of dental caries was high in high school graduates, middle school graduates, college graduates and other advanced degree holders in the order named. Low monthly income earners showed the highest prevalence of dental caries. As for health-related lifestyles, the prevalence of dental caries was higher in smokers than in non-smokers. Obese subjects showed a little higher prevalence of dental caries compared to people of normal weight. Also, the prevalence was higher in those who failed to get oral examination than otherwise. Frequent daily toothbrushing and use of dental floss and interdental brush significantly decreased the prevalence of dental caries. In the logistic regression analysis with the presence or absence of dental caries employed as a dependent variable, gender, age, income level, smoking, oral examination and use of dental floss were found to serve as independent variables affecting dental caries. Therefore, Korean adults' socio-economic factors and lifestyles were proved to affect dental caries, which warrants some dental health programs and action plans designed to help lead healthy lifestyles whilst preventing dental caries and improving dental health in adults.

• Journal of dental hygiene science
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• v.2 no.2
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• pp.53-62
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• 2002

The purpose of this study is to investigate the retention and caries prevention practical effectiveness of fissure sealant and regular checkup with cost-benefit analysis. The data of this study is based on "2000 The Survey of Korean Oral Health" by Ministry of Health & Welfare. This study is to investigate cost-benefit analysis on proper treatment for the decayed, in case of operating fissure sealant on molars at 1 year after eruption of permanent teeth. The obtained results were as follows: (1) Cost-benefit analysis on fissure sealant in 6-75 year old 43,736 thousand Korean people reveals that cost of fissure sealant is 1,610,994 million won and benefit is 69,460,691 million won. (2) Benefit of fissure sealant is 39.51 times as much as cost of fissure sealant. (3) Cost of twice in a year regular checkup is 2,678,544 million won. Indirect cost of regular checkup is 2.6 times as much as direct cost. (4) Cost of fissure sealant and twice in a year regular checkup is 4,289,538 million won, and benefit is 69,460,691 million won. Benefit of fissure sealant and twice in a year regular checkup is 16.2 times as much as cost.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.381-385
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• 2009

This study carried out to provide basic educational material of primary school children to improve the children's oral health by oral health checkup and survey over 215 students in the first grade and the fourth grade at the primary school in Hwaseong city. The collected data were analyzed by SPSS Win 12.0 program 1. The rate of students who have decayed permanent teeth was 57.2%, and there seemed to be a significant difference between the two genders showing 61.6% for male students and 53.3% for female students. Also 1st grade showed 56.0% and 4th grade 58.1% respectively. 2. The male students who claimed 'bleeding gum' against questions about oral illness experiences were 15.7% whereas female students were 28.0%. There was a significant difference(p<0.05) by the gender. 3. The 4th grade students who said 'Toothache while eating cold food' about questions of oral symptoms appeared as 19.4% and 1st grade students were 8.8%. Also there was a significant difference(p<0.05) by the grade. 4. Regarding oral health improvement behavior, there were significant differences in frequency of toothbrushing a day, the number(p<0.05) of eating snacks a day and the number(p<0.01) of experience of visiting dental clinic(p<0.01). 5. About oral health behavior frequency of daily toothbrushing was found as twice(50.2%), twice of eating snacks a day(70.2%), using fluoride toothpaste 60.9% and visiting a dental clinic(60.0%), were shown as the highest numbers.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.701-704
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• 2004

In this case, we would like to discuss about the single rooted deciduous mandibular first molar. The deciduous mandibular molar of a five years old boy was shown to have a single root, bilaterally. Ordinarily, the maxilary molars have three roots and the mandibular molars have two roots. However, when the hertwig's epithelial root sheath do not invaginate properly during tooth development, root fusion can occur from the absence of root separation. Molars with fused roots not only have unfavorable crown to root ratio, but also according to many reports, have higher probability of having multiple congenitally missing teeth or dens invaginatus in the maxillary incisors, consequently requiring preventive dental treatment In addition, disorders such as ectodermal dysplasia, syndactyly, clinodactyly, bluish sclera can also be related to this condition. Root fusion is known to be of autosomal recessive inheritance. Up to date, single rooted molars have been reported several times in permanent dentitions but hardly in deciduous dentition, which is the motive for this paper.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.106-117
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• 2013

Normal eruption of the canine is important for the transition to the permanent dentition. Etiologies, including premature loss or delayed retention of deciduous teeth, neoplasm and abnormality of lateral incisor can cause impaction of the maxillary canine. Untreated canine impaction can result in malocclusion, cyst formation and obstacles in orthodontic treatment. The aim of this study is to evaluate location of the impacted maxillary canine and to identify correlation between location and management of the impaction including complications. Using panoramic radiographs and CBCT scan, images of 89 children diagnosed with impaction of the maxillary canine, location of impacted canines was evaluated. The choice of treatment and complications were investigated to identify correlation. Results show that the most commonly impacted location of the maxillary canine was in the mid-alveolar area, followed by buccal side and palatal side. Orthodontic traction was selected more frequently than the other treatments. As complications, displacement of adjacent tooth was occurred most frequently. Buccally impacted canines showed increased tendency towards displacement. The more buccally the canine was impacted, the less orthodontic traction was chosen as the treatment. The canine impacted mesially to the central incisor showed increased tendency to occur root resorption. Therefore, early diagnosis by periodic examination, appropriate treatment and intervention is required.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.134-142
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• 2010

The purpose of this study was to evaluate the effect of Er,Cr:YSGG laser irradiation with hypersensitivity mode on microtensile bond strength of composite resin. Twenty extracted permanent molars were randomly assigned to six groups, according to the irradiation of Er,Cr:YSGG laser, adhesive system (Optibond FL or Clearfil SE bond) and application time of etchant (15 sec or 20 sec). Then composite resin was build up on each conditioned surface. The restored teeth were stored in distilled water at room temperature for 24 h and twelve specimens for each group were prepared. All specimens were subjected to microtensile bond strength and the fracture modes were evaluated. Also, the prepared dentin surface and laser irradiated dentin surface were examined under SEM. The results were as follows: 1. The microtensile bond strength of laser irradiated group was lower than that of no laser irradiated group. 2. Regardless of laser irradiation, the microtensile bond strength of Optibond FL was higher than that of Clearfil SE bond. And the microtensile bond strength of 20 sec etching group was higher than that of 15 sec etching group when using Optibond FL. 3. The SEM image of laser irradiated dentin surface showed prominent peritubular dentin, opened dentinal tubules and no smear layer.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.96-105
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• 2010

The purpose of this study is to observe and compare the remineralization tendencies of artificial enamel caries lesion by remineralization solutions of different degree of saturations at pH 5.5, using a polarizing microscope and computer programs (Photoshop, Image pro plus, Scion Image, Excel). For this study, 48 sound permanent teeth with no signs of demineralization, cracks, or dental restorations were used. The specimens were immersed in lactic acid demineralization solution for 2 days in order to produce artificial dental caries that consist of surface and subsurface lesions. Each of 9 or 10 specimens was immersed in pH 5.5 lactic acid buffering remineralization solution of four different degrees of saturation (0.507, 0.394, 0.301, and 0.251) for 12 days. After the demineralization and remineralization, images were taken by a polarizing microscope (${\times}100$). The results were obtained by observing images of the specimens, and using computer programs, the density of caries lesions were est mated. While the group with the lowest degree of saturation (0.251) showed total remineralization feature from the surface to the subsurface of the lesion, the group with the highest degree of saturation (0.507) showed demineralization mainly on the surface of the lesion at the constant organic acid concentration 0.01 M and pH 5.5.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.481-492
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• 2008

The purpose of this study is to observe and compare the remineralization tendencies of artificially demineralized enamel by remineralization solutions of different degree of saturations at pH 5.5, using a polarizing microscope and computer programs (Photoshop, Image pro plus, Scion Image, Excel). For this study, 36 sound permanent teeth with no signs of demineralization, cracks, or dental restorations were used. The specimens were immersed in lactic acid demineralization solution for 3 days in order to produce dental caries artificially that consist of surface and subsurface lesions. Each of 9 or 10 specimens was immersed in pH 5.5 lactic acid buffered remineralization solution of three different degrees of saturation (0.25, 0.30, 0.35) for 12 days. After the demineralization and remineralization, images were taken by a polarizing microscope $({\times}100)$. The results were obtained by observing images of the specimens, and using computer programs, the density of caries lesions were determined. In conclusion, in the group with the lowest degree of saturation, remineralization occurred thoroughly from the surface to the subsurface lesion, whereas in the groups with greater degree of saturation showed no significant change in the subsurface lesion, although there was corresponding increase in the remineralization width on the surface zones.

• Anatomy & Biological Anthropology
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• v.27 no.3
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• pp.155-163
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• 2014

This study aimed to investigate the cusp size and morphological characteristics of permanent mandibular molars in Koreans with reference to the hypoconulid, and to analyze the differences and correlations between both sexes as well as between first and second mandibular molars. We obtained data from dental casts of 110 adults (78 males and 32 females). Mesiodistal and buccolingual diameters of first and second mandibular molars, the area of five cusps (protoconid, metaconid, hypoconid, entoconid, and hypoconulid), as well as the total cusp area and occlusal table area were measured. Paired t-test was performed to analyze the morphological differences between first and second mandibular molars and the sex differences between both sexes using SPSS program. Crown diameters and cusp areas of mandibular first molars were larger than those of mandibular second molars in both sexes. The hypoconulid was the most variable in size and morphological pattern among the five cusps, and the first molars showed a higher incidence of hypoconulid than the second molars. Except for the entoconid area of the first molar (p=0.06) and the hypoconulid area of the second molar (p=0.24), all other mean values were larger in males than in females, demonstrating a significant sexual dimorphism. These data suggest that the teeth which develop late in ontogeny tend to be smaller in size and more variable in morphological characteristics.