• Journal of the Korea Convergence Society
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• v.8 no.1
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• pp.89-96
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• 2017

This study is to analyze seven fluoride varnishes remineralizing effects on early carious lesions in the clinical field. While CS, MI, CW, VV, EP, FP and FN were used for permanent teeth, CS, MI, CW and FP were used for primary teeth. The specimens were demineralized for 4 days after forming a $3{\times}3mm^2$ window with nail varnish, applied with varnishes separately, then were stirred in artificial saliva for 1 week. QLF-D analysis of carious lesion size showed that permanent teeth's ${\Delta}F$ value decreased after applying CS(4,64), MI(4.86), CW(4.50), and EP(5.50), while for primary teeth, FP(3.00) and MI(3.00) displayed a remineralizing effect. Thus, MI can be used effectively for preventing caries for both adults and children in the clinical field.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.171-177
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• 2013

Purpose: The purpose of this study was to compare the efficacy of two imaging modes in a cone beam computed tomography (CBCT) system in detecting root fracture in endodontically-treated teeth with fiber posts or screw posts by selecting two fields of view. Materials and Methods: In this study, 78 endodontically-treated single canal premolars were included. A post space was created in all of them. Then the teeth were randomly set in one of 6 artificial dental arches. In 39 of the 78 teeth set in the 6 dental arches, a root fracture was intentionally created. Next, a fiber post and a screw post were cemented into 26 teeth having equal the root fractures. High resolution (HiRes) and standard zoom images were provided by a CBCT device. Upon considering the reconstructed images, two observers in agreement with each other confirmed the presence or absence of root fracture. A McNemar test was used for comparing the results of the two modes. Results: The frequency of making a correct diagnosis using the HiRes zoom imaging mode was 71.8% and in standard zoom was 59%. The overall sensitivity and specificity in diagnosing root fracture in the HiRes mode were 71.79% and 46.15% and in the standard zoom modes were 58.97% and 33.33%, respectively. Conclusion: There were no significant differences between the diagnostic values of the two imaging modes used in the diagnosis of root fracture or in the presence of root canal restorations. In both modes, the most true-positive results were reported in the post space group.

• International Journal of Oral Biology
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• v.41 no.4
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• pp.243-251
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• 2016

This study was undertaken to achieve a high bleaching efficacy with plasma, through longer application and reparative bleaching processes, by different shade evaluation methods. Extracted human teeth were divided into 6 groups (n=10). All teeth were treated in pairs. Low concentration of 15% carbamide peroxide (CP) was applied, with and without plasma, for 10, 20, and 30-min tooth bleaching, respectively. The bleaching procedure was repeated once daily for four days. The teeth were maintained in a moist environment provided by artificial saliva. The Vitapan Classical shade guide and Commission Internationale de L'Eclairage (CIELAB) color system were collectively used to measure the bleaching efficacy. Color evaluation was statistically analyzed using Student t-test and one-way analysis of variance (ANOVA) complemented by Tukey's test. Combining the plasma with 15% CP showed significantly greater color changes compared to bleaching without plasma (p<0.05). A high bleaching efficacy with plasma is proportional to the repetitive application and the treatment time. A 30-min application with plasma provided the best bleaching. Repetitive bleaching showed lower probability of color relapse of the bleached tooth. The color change by shade guide correlated with the changes in CIELAB color system. A value of 1 color change units (CCU) conversion factor for overall color change (${\Delta}E$) values comparisons was 3.724 values. The two measuring methods provide a more accurate correspondence of color change. The repetitive and longer application for tooth bleaching, combined with plasma, has a strong bleaching effect and produces whiter teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.14 no.1
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• pp.17-21
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• 1976

The author studied the gingival responses to some dental cements in the gingival sulcus around artificial crowns. Abutment preparation for full veneer crown was performed in the canines of the two dogs. The location of cervical margins was about 0.5mm. below the gingival crest. Niranium metal crowns were constructed for the teeth, and cemented with zinc phosphate cement or polycarboxy late cement. In the experimental groups the retained cements in the gingival sulucus were not removed, and in the control groups the cements were removed completely after cementation. The dogs were sacrificed at 3 weeks and 5 weeks respectively after cementation. The gingival responses to these cements were examined histologically. The findings were as follows. 1. There was severe inflammation in the gingiva where the cements had been retained in the gingival sulcus around artificial crowns. 2. There was more severe inflammation in the gingiva which had contacted with zinc phosphate cement than in the gingiva with polycarboxylate cement. 3. There was mild inflammation in the gingiva around the margins of Niranium crowns. 4. The retained cement around the margin of restoration should be completely removed after cementation.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.91-95
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• 2003

Purpose : To compare the diagnostic accuracy of proximal caries detection between Kodak Insight film and the Biomedisys CDX2000HQ digital (CCD) sensor. Materials and Methods: 156 proximal surfaces of extracted teeth, 78 of which had chemical artificial caries, were used in this study. Four observers interpreted the radiographs using a five-point confidence rating scale to record their diagnoses. The results were analyzed by receiver operating characteristic curves, ANOVA and Kappa values. Result: Analysis using receiver operating characteristic curves revealed the areas under each curve which indicated a diagnostic accuracy of 0.951 in Insight and 0.952 in CDX2000HQ digital sensor. ANOVA revealed no significant differences between the two images with respect to caries detection. Kappa values indicated that the mean intra-observer agreement was 0.85 and inter-observer agreement 0.71 in conventional radiography. In digital radiography, the mean intra-observer agreement was 0.84 and inter-observer agreement 0.72. Conclusion: The results suggest that no significant difference exists between the two modalities for artificial caries detection and that CDX2000HQ was as good as Insight film for this purpose.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.180-193
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• 1994

The purpose of this study was to observe the sealing ability and durability of All-Bond 2, Gluma Bonding System, Scotch bond 2 and Superbond D-liner which are dentin bonding agents used as desensitizing agents. The durability of the sealing ability of the materials were compared after 0, 140, 420, 840 tooth brushing strokes. 120 extracted teeth were divided into 5 groups and the agents were applied to the exposed dentin. No agents was applied on group I, the control group. Each specimen went through thermocycling from $5^{\circ}$ to $55^{\circ}C$, 200 times. Each group was devide into 4 subgroups and artificial tooth brushing strokes were done for 0, 140, 420, 840 times. Finally the specimens were stored in 0.5 % methylene blue solution for 24 hours in a incubator set at $37^{\circ}C$. The tooth were sectioned perpendicular to the long axis and the dye penetration ratio to the pulp was measured. The following results were obtained. 1. All four dentin bonding agents initially showed excellent sealing ability. 2. All-bond 2, Gluma Bonding System and Superbond D-liner showed durability of dentinal tubule sealing effect after 840 strokes(6-week) artificial tooth brushing. 3. Scotchbond 2 showed a significant decrease in sealing ability after 420 strokes(3-week) artificial tooth brushing. (P<0.05).

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.109-115
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• 2012

PURPOSE. The purpose of this clinical study was to evaluate the frequency and type of prosthetic complications in relation to type and properties of removable dentures and to investigate the influence of these complications and several data about the existing dentures on patient satisfaction. MATERIALS AND METHODS. Ninety nine patients (44 males and 55 females) wearing removable dentures have been included in the study. The complications of the patients were recorded; patient satisfaction was determined with a Visual Analog Scale (VAS) and the relationship of complications and patient satisfaction with several data about the dentures such as denture age, type of denture, centric relation and vertical dimension was investigated. Kruskal Wallis, Mann Whitney U and Chi square tests were used for statistical analyses. The results were evaluated statistically at a significance level of $P$ <.05. RESULTS. Need for addition of artificial teeth for dentures with correct centric relations was found to be significantly lower than dentures with wrong centric relations ($P$ <.01). Loss of retention, ulcerations and high vertical dimension affected the VAS chewing ability scores negatively and ulcerations affected the VAS phonation scores negatively ($P$ <.05). CONCLUSION. Considering the results of this study, it can be concluded that loss of retention, ulcerations and high vertical dimension caused patient dissatisfaction. Additionally, dentures with wrong centric relations caused need for addition of artificial teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.445-450
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• 2016

Piezography, prosthetic space recorded by pronunciation, can be used as a reference for arrangement of artificial teeth and polishing surface of a denture. In this case, a 67 year old female patient was presented for new dentures. Old dentures had class II relationship and poor retention. For fabrication of stable dentures, using piezography and lingualized occlusion was planned. After taking impressions with conventional method, conventional denture bases with wax rim were fabricated. Then, additional mandibular denture base was fabricated for piezography. With fast setting silicon impression material, piezography was recorded by using six pronunciations, 'si', 'so', 'me', 'te', 'de', and 'mu'. According to the piezographic space, mandibular artificial teeth were arranged and modified for lingualized occlusion. As a result, the patient was satisfied with new dentures functionally and esthetically.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.277-290
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• 1993

Dental caries is considered to be caused by demineralization by organic acid produced by microorganism. But the formation of subsurface lesion in initial caries make it diffcult to explain by simple demineralization. This study is carried out on the basis of thermodynamic concept proposed by Margolis and Moreno. The purpose of this study is to evaluate the effects of acid concentration and pH of lactate buffer system on the artificial caries lesion progress. 160 teeth without any crack, defect or opaque enamel were used and coated with nail varnish except the window ($2{\times}3$ mm). Under the constant degree of saturation(D.S.). The teeth were divided into 8 groups according to acid concentration(10mM, 25mM, 50mM, 100mM) and pH(4.3, 5.0, 6.0). Each group was immersed in buffer solution for 3, 6, 9, 18 days under controlled temperature($25^{\circ}C$). After cutting through the window and grinding, the specimens, 100-150 um in thickness, were imbibed in water or air and examined using polarilizing microscope. The depth of the surface and subsurface surface lesion were measured. 1. In the constant pH and D. S. value, the subsurface lesion progresses more rapidly as the concentration of lactic acid increases. (0.01, 0.025, 0.05, 0.1) 2. In the constant acid concentration and DS value, the subsurface lesion progresses more slowly as the pH increases. (4.3, 5.0, 5.5, 6.0) 3. The width of surface lesion seems to be constant independant of pH and acid concentration.

• Imaging Science in Dentistry
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• v.41 no.4
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• pp.143-150
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• 2011

Purpose : The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. Materials and Methods : One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve ($A_z$) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). Results : The mean $A_z$ values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest $A_z$ value. Conclusion : Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.