• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.411-421
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• 2006

In children, during developing occlusion stage, many studies confirm a high prevalence of gingival inflammation. Prevention, early diagnosis and treatment of gingival and periodontal disease is important because by establishing excellent oral hygiene habits in children, the risk of periodontal disease can be on the decrease in adulthood. This study evaluated the gingival conditions of 50 children$(8.5{\pm}3.1years)$ and 20 $adults(26.1{\pm}3.3 years)$ receiving clinical examination and GCF test at the pediatric dentistry of Chonbuk national university hospital in Jeonju, Korea. I estimated children's and adult's gingival states by measuring gingival crevicular fluid(GCF) using Periopaper and $Periotron^{(R)}$ 8000, gingival index, plaque index, DMFT scale. The results were as follows : 1. There are no statistical differences of GCF volume among the groups of the primary dentition, tooth erupting stage, complete eruption stage(p>0.1). But mean value of GCF is highest at the tooth erupting stage. 2. Comparing with adults, children have higher mean value of GCF volume with statistical differences (p<0.001). 3. There is statistically positive relationship between volume of GCF and gingival index (GI), plaque index(PLI) in both adults and children(GI; r=0.394, PLI ; r= 0.642). 4. There is no relationship between GCF volume and dental caries, composite resin treatments (p>0.05). But There is statistically positive relationship between GCF and orthodontic treatments(p<0.001) 5. Primary dentition has higher mean value of DMFT than permanent dentition(p<0.001). But there is no statistical relationship between GCF and DMFT (p>0.1).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.625-630
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• 2009

Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.278-286
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• 2008

Many studies regarding Casein phosphopeptides-amorphous calcium phosphate(CPP-ACP) have demonstrated the remineralization ability on the demineralized enamel surface. A question is still remained that how deep can the calcium (Ca) and phosphorus (P) ions supplied by the CPP-ACP paste penetrate into the enamel subsurface. The aims of this study were to measure the penetrating depth of Ca and P ions in the demineralized human enamel in vitro, and were to determine the amount and depth of Ca and P ions according to the duration. The amount and depth of Ca and P ions were measured by microscopic observation with Field Emission Scanning Electron Microscopy (FE-SEM; LEO SUPRA 55, Carl Zeiss, Germany) and Energy Dispersive X-ray Spectrometer (EDS; GENESIS 2000, EDAX, USA: Linescan of Calcium and Phosphorus). Freshly extracted four human 1st premolars were obtained from the Dept. of Pediatric Dent., Kyung Hee Univ. Buccal surfaces of the 1st premolars were covered with nail varnish to form a window on the middle third of buccal surface. All of the teeth with enamel windows were immersed in a solution of 0.1 M lactic acid, Carbopol C907 (carboxypolymethylene BF Goodrich, Cleveland, OH, USA) at pH 4.8, and then incubated for 7 days. Each tooth crown was sawn in half through the midline of buccal window along the long axis of premolar. The four blocks of premolars were immersed in a 10-times diluted solution of CPP-ACP paste (Tooth Mousse, GC Corp., Tokyo, Japan) for 1, 2, 3 and 5 weeks while the rests were immersed in a placebo solution (distilled water) for the same duration. Each specimen was embedded in epoxy resin, and was sectioned perpendicular to the window, using a water-cooled diamond blade saw. The spectrum density indices of Ca and P were measured in the sound, de- and remineralized enamels by FE-SEM and EDS. The Student's t test was performed to compare the Spectrum Density Indices (SDI) of sound, re-and demineralized enamels, and to compare the differences among the durations. Followings are the conclusion : 1. The penetration depth of the remineralizing ions (Ca & P) of CPP-ACP paste is related to the depth of demineralized enamel (approximately $1050{\sim}1350{\mu}m$). It is revealed that the penetration depth of both ions reaches full thickness of decalcification and even slightly into the sound enamel. 2. The Ca & P levels of remineralized enamels in 1, 2 weeks were significantly higher than those of the sound enamels (p<0.05). 3. No statistically significant difference of Ca & P levels was found in relation with the increasing duration of remineralization (p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.791-799
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• 1996

The purpose of this study was to compare the shear bond strength of adhesion bridge by various resin cements. One hundred and foully 1st premolars were used. The teeth were cut below 2mm from CEJ and the coronal portions were used. The coronal portions were embeded with the acrylic resin and trimmed with sic paper until the flat plane with ${\phi}$ 4mm above acrylic resin sticks in height 5mm were casted with nonprecious metal and the using surfaces were treated with sic paper from #200 to #1200 and polished with alminum oxide paste. And then, the using surfaces were sandblasted and treated with the electrochemical etching. The teeth were divided into three groups of fourty two each. In group I, teeth and specimens were cemented with Panavia 21 In group II, teeth and specimens were cemented with Superbond In group I, teeth and specimens were cemented with All-Bond & composite resin cement Each group was subdivided into three subgroups according to the storage period ; one-day storage, fifteen-day storage, and thirty-day storage. The special jig was made. Then, the specimen and jig were mounted to Instron Universal Testing Machine and the failure were measured. The results were as follows. 1. There was statisfically significant difference between the failure loads of group I and group II and III after one day storage(P<0.01), 2. There was statisfically significant difference between the failure loads of group II and group I and III and between group I and group III at fifteen day storage(P<0.01). 3. There was statisfically significant difference between the failure loads of group I and II and group III after thirty day storage(P<0.01). 4. There was statisfically significant difference between the failure loads of one day storage and fifteen and thirty days storages in group III (P<0.01).

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.310-317
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• 2015

Purpose: The purpose of this study was to evaluate the validity of reference points for edentulous patient by examining the correlation of teeth and face, and intraoral anatomic landmarks. Materials and methods: We examined a facial outline, length, bizygomatic width, nasion - gnathion length, glabella - nasion distance in 270 men and 280 women satisfied with inclusion criteria from Seoul National School of Dentistry. The shape of maxillary central incisor, mesiodistal crown width and length of maxillary 6 incisors, distance from incisive papilla to labial surface of maxillary central incisor, and perpendicular distance from incisive papilla to intercanine line were measured in the stone model. We analyzed the ratio and relevant relation statistically. Results: The probability on having the same shape of face and the relative same shape maxillary incisor was 55.56% and 46.43% for men and women. The facial length proved to be a more valuable measurement in women in the tooth selection. The ratio of bizygomatic width to mesiodistal width of maxillary central incisor, and the ratio of bizygomatic width to width of maxillary 6 incisors were 16.8 : 1 and 3.0 : 1 and were positively correlated with each other. The distance of the canines from the maxillary incisal papilla was $1.33{\pm}1.28mm$. The distance between the center of the incisal papilla and the labial surface of their maxillary central incisor was $9.23{\pm}1.20mm$. Conclusion: It was showed that anatomical reference points in tooth selection and arrangement for edentulous patient are useful and have validity in our limited study.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.207-217
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• 2014

The purpose of the present study was to evaluate the relationship between the malocclusion and dental caries in adolescents with permanent dentition. The subjects of the study were 385 adolescents aged 12 to 15 years. Dental Aesthetic Index (DAI) and DMFT index were recorded as clinical indicators of malocclusion and dental caries. The mean Dental Aesthetic Index (DAI) score of the subjects was 12.42 and the mean DMFT index of the subjects was 2.89. Four students (1.04%) were included in the group of orthodontic treatment mandatory, which signifies the handicapping malocclusion. Moreover, the result of gender-specific analysis of the DAI components observed that the prevalence of midline diastema and mandibular overjet were significantly higher among boys (p < 0.05). In 7 components (missing teeth, incisal segment crowding, maxillary anterior irregularity, mandibular anterior irregularity, mandibular overjet, anterior openbite, antero-posterior molar relationship) among the 10 DAI components, abnormal groups showed significantly higher DMFT index than normal groups (p < 0.05). The subjects in the group of definite to handicapping malocclusion (DAI ${\geq}$ 26) showed significantly higher DMFT index than the subjects in the group of minor or no malocclusion (p < 0.01). In addition, the DAI score had significant positive linear correlation with the DMFT index (r = 0.584, p < 0.01). Consequently, the current findings suggested a positive relationship between the malocclusion and caries prevalence. And several specific types of malocclusion were supposed to be significantly correlated with dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.636-644
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• 2004

Recently, self-etching adhesive system have been developed and bonding procedures simplified into one or two steps, which are simultaneously applied to both enamel and dentin. These systems are easy to use and have the potential for good clinical success. The purpose of this study is to evaluate in vitro the microleakage on the cementum/dentin and enamel walls in composite resin restoration of Class V cavities, regarding the use of different adhesive systems. 30 human premolars were divided into 3 groups. A standardized Class V preparation was prepared on the buccal and lingual surface of each premolar. The preparation were made parallel to the cementoenamel junctions, with the gingival half of the preparation extending 1mm apical to the cementoenamel junction. After adhesive system was applied to teeth as manufacture's recommendation, hybrid resin composite was filled in bulk into the preparation and light polymerized according to manufacturer's recommendations. Specimen were stored in distilled water at $37^{\circ}C$ for 5 days and thermocycled 1000 times ($5^{\circ}C{\pm}2^{\circ}C\;and\;55^{\circ}C{\pm}2^{\circ}C)$, then immersed in a 2% methylene blue solution for 12 hours. After sectioning mesio distally through the restorations, the degree of dye penetration was scored under a stereomicroscope at ${\times}\;25$ magnification. The data were analyzed statistically using t-test and one-way ANOVA. The results were as follows: ${\cdot}$ There is no adhesive system which can prevent microleakage perfectly. ${\cdot}$ There is significant difference in microleakage between enamel margin and dentin margin (p<0.0001). ${\cdot}$ In enamel margin, self-etching primer systems did not show any significant difference comparing total-etching system. In denin margin, self-etching primer systems did not show any significant difference comparing one-bottle adhesive system used in combination with total-etching.

• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.279-294
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• 2008

This study aimed to make an analysis of the occlusion in the state of muscle fatigue produced by excessive mouth opening and clenching during the dental treatment to control the dental pain and to evaluate the sensory nerve in the muscle pain state. Most of the reasons why patients visit the dental office result in pain-either conceivably the dental origin pain or the non-dental origin pain. The dental offices have many therapeutic actions to produce the masticatory muscle fatigue for the treatment. Dental treatment with long minutes of mouth opening can cause some headaches, masticatory muscle pain and mouth opening difficulties. Patients with mastication problems who visits a dental office to alleviate pain run against another unexpected pain with other aspects. This study uses T-scan II system(Tekscan Co., USA) for the evaluation on the occlusal pattern in the experimental muscle fatigue after clenching, opening the mouth excessively and chewing gum. The occlusal contact pattern is analyzed by the contact timing, namely first, intercuspal, maximum and end point of contact. This inspection was performed at frequencies of 2000Hz, 250 Hz and 5 Hz before and after each experimental muscle pain was produced to 24 subjects who had normal occlusion without the orthodontic treatment or a wide range of the prosthesis by using $neurometer^{\circledR}$ CPT/C(Neurotron, Inc. Baltimore, Maryland, USA). The measuring sites were mandibular nerve experimental muscle fatigue respectively. This study could obtain the following results after the assessment of occlusion and sensory nerve of the experimental muscle fatigue. 1. There were the fastest expression after the excessive mouth opening in muscle fatigue and after tooth clenching in muscle pain. In the visual analog scale that records the subjective level, there was the highest scale after the clenching in the muscle fatigue in jumping off the point of pain. 2. Tooth contact time, contact force, relative contact force on the point of the first contact had no difference, and there were decreases in the contact force after the excessive mouth opening on intercuspal position point, after the excessive mouth opening and the gum chewing on the point of the maximum, and in the contact time after all the experimental muscle fatigue state on the point of the end contact. 3. There was no statistic significance in the current perception threshold before and after the experimental muscle fatigue. 4. There was no significant difference in the contact number, the maximal contact number on the point of the first contact, and the contact number after the mouth opening and gum chewing on the point of the intercuspal position and the contact number after the experimental muscle fatigue on the maximum point, and showed significant decreases. In conclusion, it was found that the occlusal pattern can cause the changes on the case of the clinical muscle weakness by intra-external oral events. It was important that the sedulous attention to details is required during dental treatment in case of excessive mouth opening, mastication and clenching.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.413-426
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• 1992

In order to analyze the relationship between teeth and basal bone for the maintainance of the good occlusion, the mesiodistal width of teeth, the basal arch width and the basal arch length were measured on the study model of the normal occlusion group and Angle's class I malocclusion group (non-extraction group, extraction group) The Maximum tooth material, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material were caculated, and then statistical analysis was done. From thie study, the obtained results were as follows; 1. In maxilla, the percentage of basal arch width to maximum tooth material was $46.9{\pm}2.6\%$ in normal occlusion group, $49.4{\pm}3.9\%$ in non-extraction group, and $42.5{\pm}3.3\%$ in extraction group. In mandible, that was $46.6{\pm}2.4\%$ in normal occlusion group, $47.5{\pm}4.0\%$ in non-extraction group, and $42.6{\pm}2.6\%$ in extraction group. 2. In maxilla, the percentage of basal arch length to maximum tooth material was $33.4{\pm}1.9\%$ in normal occlusion group, $33.9{\pm}1.8\%$ in non-extraction group, and $28.7{\pm}2.5\%$ in extraction group. In mandible, that was $34.4{\pm}4.3\%$ in normal occlusion group, $36.5{\pm}1.9\%$ in non-extraction group, and $31.5{\pm}2.5\%$ in extraction group. 3. In maxilla, the percentage of basal arch width plus basal arch length to maximum tooth material was $80.3{\pm}3.4\%$ in normal occlusion group, $83.3{\pm}4.8\%$ in non-extraction group, and $71.2{\pm}4.3\%$ in extraction group. In mandible, that was $81.0{\pm}5.2\%$ in normal occlusion group, $84.0{\pm}5.4\%$ in non-extraction group, and $74.1{\pm}4.1\%$ in extraction group. 4. In Maxilla, the $95\%$ confidence interval of the percentage of basal arch width to maximum tooth material was $46.3-47.5\%$ in normal occlusion group, $48.1-50.7\%$ in non-extraction group, and $41.7-47.2\%$ in extraction group. In mandible, that was $46.1-47.2\%$ in normal occlusion group, $46.1-48.8\%$ in non-extraction group, and $42.0-43.3\%$ in extraction group. 5. In maxilla, the $95\%$ confidence interval of the percentage of basal arch length to maximum tooth material was $32.9-33.9\%$ in normal occlusion group, $33.3-34.5\%$ in non-extraction group, and $28.1-29.2\%$ in extraction group. In mandible, that was $33.4-3.4\%$ in noraml occlusion group, $35.8-37.2\%$ in non-extraction group, and $30.9-33.1\%$ in extraction group. 6. In maxilla, the $95\%$ confidence interval of thepercentage of basel arch width plus basal arch length to maximum tooth material was $79.5-81.0\%$ in normal occlusion group, $81.6-84.9\%$ in non-extraction group, and $70.1-72.2\%$ in extraction group. In mandible, that was $79.8-82.2\%$ in normal occlusion group, $82.1-85.5\%$ in non-extraction group, and $73.1-75.1\%$ in extraction group. 7. There was correlation between maxilla and mandible in the maximum tooth material, the basal arch width, the basal arch length, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material, but not in the basal arch length of male of the extraction group. * A thesis submitted to the Council of the Graduate School of Kyungpook national University in partial fulfillment of the requirements for the degree of Master of Dental Science in December, 1991.

• Sijohaknonchong
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• v.23
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• pp.107-131
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• 2005

The purpose of this is to make sure what the scholar of the Choseon thought the object of aesthetics, and which psychological element did they use to clear the center of the aesthetics. In addition, I consider their way to recognize the human's aesthetic point of view. A literary man in Choseon regarded the five senses as an obstacle which interrupted to see the nature of all things. So they set up the spiritual condition as their aesthetic subject, with suppressing the pleasure through five senses. The goal to make one's mind calm was to cause someone's spirit to activate freely. The condition of the calmness was considered as a process of recovering the human's natural spirit, which was connected to the poetic spirit and became the aesthetic subject. Simultaneously, a literary man at that time set up the condition of the calmness as a subject of objective consciousness, and estimated the common things as a objective existence, which led to the result that all the materials of the poem and the poet could be unified. This aesthetic centra put a premium on the senses caused by contacting with all natural things, and adopted the 'Xing' as a method of expression. This 'Xing' is not a sense based upon one's experience, but a sense which is created of itself. The expression method of 'Xing' caused the reader to feel and express, encourage, and sublimate what they feel through the poem, as well as purified reader's mind.