• The Journal of Advanced Prosthodontics
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• v.6 no.6
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• pp.434-443
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• 2014

PURPOSE. The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS. A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of $6mm{\times}4mm$ and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with $30{\mu}m$ silica oxide particles ($Cojet^{TM}$ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at ${\alpha}=.05$. RESULTS. Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION. Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.564.1-564
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• 2001

Porphyromon as endodontalis, a gram-negative anaerobic rod, is an important pathogenic organism in periapical lesionis with acute symptoms, such as pain, swelling, and suppuration in endodontic patient. Like P. gingivalis, a major pathogen of adult periodontitis, P. endodontalis is asaccharolytic and forms black-pigmented colonies on enriched blood agar plates. However, the pathogenic factors and the pathological potential of this microbe have been poorly characterized.(omitted)

• The Journal of the Korean dental association
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• v.11 no.2
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• pp.131-133
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• 1973

A Case of a supernumerary teeth on the buccal side of upper right and left molar teeth was observed from a 21 years young Korean female. The characteristics were as follows : 1. The site of the occurrence were resemble on the right and left sides. 2. The cusps of the supernumerary tooth on the right side were resemble to the premolar, and the cusp of the left one was added by one more cusp than the normal molar tooth. 3. The supernumerary teeth were smaller than the normal teeth size. 4. The right and left teeth had only one root.

• Imaging Science in Dentistry
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• v.33 no.4
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• pp.223-229
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• 2003

Purpose: To compare the effects of the conservative treatment and operative treatment by observation of osseous changes of the TMJ and mandibular asymmetry in condylar fracture patients. Materials and Methods: 33 condylar fracture patients (17 with conservative and 16 with operative treatment) were included in this study. After a minimum of 6 months after the surgical procedure, patients were given a follow up examination of the osseous changes using a transcranial view. Differences in the osseous changes of both groups were compared and the asymmetry indices were calculated on a postero-anterior skull view. Results: The TMJ of the operative treatment group showed more significant osseous changes than the conservative treatment group. The affected TMJ showed more significant osseous changes than the unaffected TMJ in the both groups. The unaffected TMJ of the conservative group and the affected TMJ of the operative group showed significant osseous changes. The mandibular asymmetry indices in the conservative and operative group were 5.12 and 7.30 respectively at the time of treatment, and 2.39 and 3.41 respectively at the follow-up. But the mandibular asymmetry between the both groups showed no statistical differences. Conclusion: The TMJ of the operative group showed more significant osseous changes than the conservative group, but the mandibular asymmetry between the both groups showed no statistical difference.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.23-38
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• 1988

In order to investigate the material formed by application of fluoride on human dentin, exposed dentin of tooth cervix and sound dentin powder was treated by several fluoride solutions. The former was observed by scanning electron microscope and the latter was analysed by x-ray diffractometer and infrared spectrophotometer. The results obtained were as follows: 1. Application with NaF, $SnF_2$ and $Na_2PO_3F$ on exposed dentin of tooth cervix formed mineralized materials covered. 2. The amount of mineralized materials increased with time intervals of applying the fluorides. 3. The density of mineralized materials was highest in $Na_2PO_3F$ treatment group, and NaF treatment group was higher than $SnF_2$ treatment group. 4. $SnF_2$ remained in covering of mineralized materials. 5. Application with NaF and $Na_2PO_3F$ formed mineralized materials characterized apatitic crystals. 6. The crystallinity of mineralized materials was higher prominently in $Na_2PO_3F$ treatment group.

• Restorative Dentistry and Endodontics
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• v.11 no.1
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• pp.53-61
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• 1985

This study was conducted to evaluate and compare the apical leakage in the following retrograde techniques; apicoectomys, retrograde filling with zinc oxide eugenol cement, non-zinc and zinc amalgam, and cold-burnished gutta-percha method. One hundred twenty five upper anterior and lower premolar teeth were divided into five above mentioned groups and each tooth was individually prepared for its particular group. The specimens were incubated at $37^{\circ}C$ for 14 days and then were infiltrated by 2% methylene blue for 24 hours. The apical leakage was evaluated by measuring the degree of dye penetration between the filling material and the canal wall. The results were as follows: 1. The cold-burnished gutta-percha group showed the least amount of apical leakage and the apicoectomy group showed the greastest amount of apical leakage. 2. Statistics showed that there were significant differences among the groups (P<0.05), however there was no difference between the zinc oxide eugenol cement retrograde filling group and the non-zinc amalgam retrograde filling group (P>0.05).

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.17-30
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• 1984

This study was done to evaluate the hardness, water sorption and solubility values of twelve well known composite resins, and to compare each other. For the hardness test, the specimens were made in cylinder form with 4mm in diameter and 2mm in thickness as a modification of the American Society for Testing and New Materials, 1966, and for water sorption and solubility tests, the specimens were prepared in same shape of 20mm in diameter and 0.5mm in thickness as a modification of the ADA Specification No. 12. The results were obtained as follow: 1. The hardness range were from 17.9 to 87.5 respectively. As time passed by, the noticable change was evident in early 12 hours. 2. Of the water sorption. the range was from 0.38 to 0.93. The significant change was appeared within 12 hours and on 3 day by 1 week except four brands. 3. Of the water solubility, the range was 0.06 to 0.16. The highest value was found within early 24 hours. 4. Generally, four brands could be chosen as preferable products of hardness. water sorption and solubility tests according to the ADA Specification No. 12.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.103-114
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• 1984

The purpose of this study was to compare the polished surfaces of two composite resins (Clearfil F and Durafill) with those of glass ionomer cement (Fuji ionomer cement) and to observe what types of polishing devices are valuable, and then to establish a clinically satisfactory procedures. Studies have been undertaken to determine the effects of glass plate matrix and finishing instruments (Carborundum point, White point and Sof-Lex medium) on the surface finish of three restorative materials. The results were examined with profilometer (Kosaka laboratory LTD. Tokyo, Japan) and scanning electron microscopy (JSM-T20: JEOL). The results were as follows: 1. The most satisfactory surface finishes were produced against glass matrix. 2. Coarser finishes were obtained with use of carborundum point. 3. Generally Fuji ionomer cement were left surfaces with higher roughness values. 4. The smoothest finishes were obtained with Sof-lex medium. 5. Clearfil-F was showed more smoother than the other restorative materials.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.71-83
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• 1984

The purpose of this study was to evaluate the transmission spectrum of the set calcium hydroxide dental cement (Dycal, L.D. Caulk Co. Milford, Del.) Cement was prepared for A T R spectra at a low powder-to-liquid ratio of 3.0gm/ml in order to retard the reaction and facilitate the manipulation of loading the cement into the cell. Spectra were recorded on an I R Spectrophotometer (MX-1, FT) at an agle of incidence of 55. The A T R cell was a RIIc Model TR5 with a hemisperical KRS-5 (Thallium-Bromide-Iodide). A spectrum was recorded within 3 minutes. Further spectra were recorded after 5,10,30 minutes and 1,5,24, 72 hours. The results were as follows; 1. The setting reaction between acid paste and base past would take place fastly within 10 minutes after mix, and that would be slow until 72 hours after mix. 2. In the set cements, some methyl salicylate and calcium hydroxide remained unreacted until 72 hours after mix. 3. The setting reaction and the reaction rate occuring at the surface and in the bulk cements were similar. 4. The chelates were bound together between calcium hydroxide and methyl salicylate.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.113-118
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• 2013

Nowadays, oral anticoagulants are commonly prescribed to numerous patients for preventing cardiovascular accident such as thromboembolism. An important side effect of anticoagulant is anti-hemostasis. In a major surgery, the oral anticoagulant therapy (OAT) regimen must be changed before the surgery for proper post-operative bleeding control. However, in a minor dental surgery and endodontic surgery, the necessity for changing or discontinuing the OAT is open to debate. In this study, risks of the consequences were weighed and analyzed. In patients who stop the OAT, the occurrence of thromboembolic complication is rare but the result is fatal. In patients who continuing the OAT, post-operative bleeding can be controlled well with the local hemostatic measures. In the endodontic surgery, there are almost no studies about this issue. The intra-operative bleeding control is particularly important in the endodontic surgery because of its delicate and sensitive procedures such as inspection of resected root surface using dental microscope and retrograde filling. Further studies are necessary about this issue in the viewpoint of endodontic surgery.