• Restorative Dentistry and Endodontics
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• 제11권1호
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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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• 제27권1호
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• pp.12-15
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• 2002

The first purpose of present study was to compare the anticariogenic effect of compomer, resin modified glass ionomer cement and composite (RMGIC). The second purpose was to evaluate the recently introduced methods, which use confocal scanning micro-scope, in detecting initial caries around restoration. 2$\times$4$\times$1.5mm cavities were prepared from the recently extracted 50 human teeth on the buccal or lingual surface. The prepared teeth were randomly devided into 5 groups and restored with each filling material. Group 1: Dyract AP, Group 2: compoglass F, Group 3: F2000, Group 4: Z100. Group 5:Fuji II LC. The teeth were stored for 30 days in the distilled water, then stored in the buffer solution for artificial caries development: pH 4.3, lactic acid 100 mM, calcium 16 mM, phosphate 8mM, sodium azide 3mM. Then, the samples were sectioned longitudinally and examined with confical scanning microscope. The results showed that the use of compomer and resin modified glass ionomer cement showed caries inhibition zone whereas the composite did not. There was no difference in the width of caries inhibition zone between compomers and RMGIC. The confocal scanning microscope was useful in detecting initial caries around restoration.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.483-496
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• 1993

Dentin hypersensitivity medicaments such as Gluma, Scotchbond 2, All-Bond 2, which are resin adhesives, were used to compare the sealing effects of dentinal tubule under mechanical stress. Topical application of above medicaments on the dentin surfaces of extracted teeth followed by artificial tooth brushing for 6 weeks was performed for the comparison. The following conclusions on the degree of dentinal tubule exposure versus time by were reached by using polyvinyl siloxane impression material for taking the impression, epoxy resin for the duplication and SEM for observing the surface. 1. SEM was used to compare the accuracy of the duplicated surface, but no differences were found when teeth samples and the duplicated surfaces were observed. 2. After comparing the degree of dentinal tubules exposure with varnish applied contrast group, resin adhesive materials showed much less exposure as time went by. 3. The results indicated that AU-Bond 2 adhesive, under mechanical stress, showed lesser exposure of dentinal tubules comparing with Gluma and Scotchbond 2 adhesives After the results were put together, it was demonstrated that resin replica method is an useful way to evaluate the treatment effects of the dentinal tubule hypersensitivity medicaments. Also, it was noticed that under mechanical stress, All-Bond 2, classified as fourth generation, illustrated the best dentinal tubules sealing effects.

• Restorative Dentistry and Endodontics
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• 제41권1호
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• pp.63-67
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• 2016

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar.

• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.31-37
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• 1989

The purpose of these study was to compare the sealing ability of a injection-molded thermoplasticized gutta-percha and silver amalgam as retroseal material in vitro. Sixty two upper and lower extracted human teeth with single root were randomly selected and instrumented in a conventional method with H-file. After instrumentation the root canal was obturated with gutta-percha by lateral condensation technique with AH26 and an apicoectomy was performed by beveling the root tip 45 angle. In the experimental group 1 and 2, a class I preparation was made and filled with silver amalgam or gutta-percha and in the experimental group 3 an apicoectomy only was performed. All specimens were immersed in black Indian ink, decalcified and cleared. The depth of dye penetration into the canals were evaluated by califer. The results were as follows ; 1. The experimental group 1 displayed the smallest mean dye penetration as 0.45mm. 2. The experimental group 3 displayed the greatest mean dye penetration as 0.65mm. 3. There was the difference in dye penetration between each group, but the difference was not statistically significant(P>0.05).

• 대한가정학회지
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• 제49권5호
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• pp.11-22
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• 2011

This study aimed to suggest more appropriate and accurate festival costumes based on a comparative analysis on various reproduced costumes and a period review of traditional festival costumes. In particular, the comparative analysis examined festival costumes which appeared in Korean and Japanese festival parades during the Baekje Period. The Baekje Cultural and Sacheonwangsawasso Festivals were examined. A literature review as well as field research and digital restorative techniques were used in the study. The reproduction patterns of Baekje costumes from both festivals were compared with original Baekje costumes, demonstrating several differences in the configuration, material, color, and shape of the costumes in addition to the way they were worn. Based on the comparative analysis, Baekje costumes used in Festivals were grouped into three categories: King's Costume, Queen's Costume, and Government Official's Costume. Dress sketches and 3D illustrations also have been presented.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.20-32
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• 1990

The plane strain fracture toughness of a material characterize the resistance to fracture in the presence of a sharp crack under severe tensile condition. Fracture toughness can be determined by indentation method. The purpose of this study was to investigate the fracture toughness of dental amalgams by measuring the plane strain fracture toughness and the fracture toughness from indentation method. Two conventional and four high copper amalgam alloys were employed for this study. The amalgams were prepared according to the A.D.A. spec. No. 1 and inserted into the specially designed mould with the single edge notch specimen to use in 3-point bending method. The specimens (20mm long, 4mm wide, 2mm thick) were stored at $37^{\circ}C$ for 1 week, and tested in 3-point bending by means of Instron at a cross-head speed of 1mm/min. In indentation method, the specimens were made in same manner as single edge notch specimens. The test was conducted with Vickers hardness tester at 10kg load. The following results were obtained. 1. The plane strain fracture toughness and the fracture toughness from indentation method were higher in the low copper amalgams than the high copper amalgams. 2. In high copper amalgams, the fracture toughness of amalgams decreases according as the copper contents increase. 3. In similar copper contents, the single composition amalgams have a higher fracture toughness than the admixed amalgams.

• Restorative Dentistry and Endodontics
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• 제38권4호
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• pp.248-252
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• 2013

Objectives: Fast-setting pozzolan cement (Endocem, Maruchi) was recently developed. The aim of this study was to investigate the effects of various root canal irrigants on the washout of Endocem in comparison to the previously marketed mineral trioxide aggregate (ProRoot; Dentsply) in a furcal perforation model. Materials and Methods: ProRoot and Endocem were placed into acrylic molds on moist Oasis. Each mold was then immediately exposed to either physiologic saline, 2.5% sodium hypochlorite (NaOCl), or 2% chlorhexidine (CHX) under gentle shaking for five minutes. Washout testing was performed by scoring scanning electron microscope (SEM) images. Results: Endocem exhibited higher washout resistance compared to ProRoot, especially in the NaOCl group. Conclusions: These results suggest that Endocem can be considered a useful repair material for furcal perforation, especially in a single-visit scenario.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.310-315
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• 2016

Two case reports describing a new technique of creating a repositionable piezoelectric bony window osteotomy during apicoectomy in order to preserve bone and act as an autologous graft for the surgical site are described. Endodontic microsurgery of anterior teeth with an intact cortical plate and large periapical lesion generally involves removal of a significant amount of healthy bone in order to enucleate the diseased tissue and manage root ends. In the reported cases, apicoectomy was performed on the lateral incisors of two patients. A piezoelectric device was used to create and elevate a bony window at the surgical site, instead of drilling and destroying bone while making an osteotomy with conventional burs. Routine microsurgical procedures - lesion enucleation, root-end resection, and filling - were carried out through this window preparation. The bony window was repositioned to the original site and the soft tissue sutured. The cases were re-evaluated clinically and radiographically after a period of 12 - 24 months. At follow-up, radiographic healing was observed. No additional grafting material was needed despite the extent of the lesions. The indication for this procedure is when teeth present with an intact or near-intact buccal cortical plate and a large apical lesion to preserve the bone and use it as an autologous graft.

• 대한치과보철학회지
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• 제19권1호
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• pp.47-54
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• 1981

Dental porcelains are widely used for restorative material because of its excellent esthetic property. But according to contact with natural teeth or metal in oral cavity, the porcelain may be worn and may effect on masticatory physiology and prosthetic function. The purpose of this experiment was to study on wear of porcelain surface which treated in different method. Using the abrasion device which was designed and constructed by myself, the different porcelain surface were abraded by gold alloy, nickel-chrome alloy and natural teeth in order to compare roughness. Results were as follows. 1. The group of porcelain abraded by gold alloy showed less surface roughness change (t=2.92, p<0.05), and the group of porcelain abraded by natural teeth had high surface roughness. change (t=6.84, p<0.05). 2. According to the method of surface treatment, the surface roughness were very significant (F=9.12, p<0.05). 3. After abrading, the porcelain surface roughness change was very significant (F=54.49, p<0.05). 4. There was no significant between surface treatment method and the kind of abrading materials. (F=1.01, p>0..05). 5. The group of natural glazing had the most smooth surface ($2.1{\pm}1.13{\mu}m$).