No abstract available.
Suicide, Attempted*

STATEMENT OF PROBLEM: When veneering composite resin-metal restoration is prepared, the fact that bond strength between Ti and composite resin is relatively weak should be considered. PURPOSE: The purpose of this study is to evaluate the shear bond strength between the veneering composite resin and commercial pure (CP) Ti / Ti-6Al-4V alloy according to the method of surface treatment. MATERIAL AND METHODS: The disks were cast by two types of metal. Their surfaces were treated by sandblasting, metal conditioner, TiN coating and silicoating respectively. After surface treatment, the disks were veneered by composite resin (Tescera(TM), Bisco, USA) which is 5 mm in diameter and 3 mm in thickness. The specimens were stored in water at 25degrees C for 24 hours, and then evaluated for their shear bond strength by universal testing machine (STM-5(R), United Calibration, USA). These values were statistically analyzed. RESULTS: 1. All methods of surface treatment were used in this study satisfied the requirements of ISO 10477 which is the standard of polymer-based crown and bridge materials. 2. The metal conditioner treated group showed the highest value in shear bond strength of CP Ti, silicoated group, TiN coated group, sandblasted group, in following order. 3. The silicoated group showed the highest value in shear bond strength of Ti-6Al-4V alloy, metal conditioner treated group, sandblasted group, TiN coated group, in following order. CONCLUSION: Within the limitations of this study, all methods of surface treatment used in this study are clinically available.
Alloys ; Calibration ; Collodion ; Crowns ; Tin ; Titanium ; Water

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study. Samples were divided into two groups: the denture base resin with chitosan, without chitosan. Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows: Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan,but less bacteria adhered on them.
Bacteria* ; Cell Count ; Chitosan* ; Denture Bases* ; Dentures* ; Lactobacillus casei ; Polymethyl Methacrylate ; Streptococcus mutans

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth.To prepare for the experimental samples,first,extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens.Next,each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces.Then,the enamel(E)and dentin(D)specimens were divided into four; 1) non-bleached,laser-treated(NBLA)group 2)bleached,laser-treated(BLLA)group 3)non-bleached,acid-treated(NBAC)group and 4)bleached,acid-treated(BLAC)group.Here,opales-cence(R)(10%carbamide peroxide)was used for bleaching agent.The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment : 1. Compared with the ENB group,the EBL group was shown to be dyed about 20 micrometer deeper with rhodamine B.The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about 20 micrometer deeper and 5 micrometer wider in diameter,compared with the DNB group. 2. In comparison with the EBLAC group,the ENBAC group looked evenly bonded with the resin, while the DNBAC group,compared to DBLAC group,was observed to have its resin tags penetrated about 50 micrometer deeper.Other than those,however,no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3. At the shear bond test,the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p<0.05).No statistically significant differences between the ENBLA and the EBLLA groups were observed(p>0.05). 4. At the shear bond test,the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p<0.05).No statistically significant differences between the DNBLA and the DBLLA groups were observed(p>0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.
Crowns ; Dental Enamel* ; Dentin* ; Humans ; Microscopy, Confocal* ; Molar, Third ; Plastics ; Rhodamines ; Tooth

STATEMENT OF PROBLEM: The microbial adhesion on the surface of materials used in prosthodontics and restorative dentistry significantly influences microbial infection. PURPOSE: The purpose of this study was to evaluate the effect of how the degree of surface roughness of acrlyic resin affect the adhesion of bacteria. MATERIAL AND METHODS: Resins were finished with 50micrometerand 250micrometeraluminium oxide particles by using sandblaster, by using stone point, and high polished with Opal(R) and Lace motor(R). The surface of acrylic resin attached by bacteria was directly touched on the surface of BHI agar, which was incubated. Bacteria colonies formed on BHI agar were counted in accordance with the degree of the surface roughness. RESULTS: 1. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated in BHI broth than in PBS. 2. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated without agitation than with agitation, washed three times than six times, and incubated in broth added with 5% sucrose than without sucrose. 3. When Streptococcus mutans incubated in BHI broth, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with 250micrometeraluminium oxide particle using sandblaster. But when incubated in BHI broth containing sucrose, the number of colonies formed on that was the largest on the acrylic resins high polished using Opal(R) and Lace motor(R). 4. When Streptococcus sanguis was incubated in BHI broth with or without sucrose, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with 250micrometeraluminium oxide particle using sandblaster. 5. When Actinomyces viscous was incubated in BHI broth with or without sucrose, the number of Streptococcus mutanscolonies formed on BHI agar was the largest on the acrylic resins high polished using Opal(R) and Lace motor(R). CONCLUSION: These results indicated that when acrylic resins attached by bacteria were touched on the surface of BHI agar, the number of bacterial colonies formed on the agar was dependent on the bacterial species. Also, the result of this study was showed that increase in the surface roughness and the addition of sucrose increased retention of microbial cells.
Acrylic Resins ; Actinomyces ; Agar ; Bacteria* ; Cell Count ; Dentistry ; Dihydroergotamine ; Prosthodontics ; Streptococcus ; Streptococcus mutans ; Streptococcus sanguis ; Sucrose

STATEMENT OF PROBLEM: It is known that an anodic oxidation technique, one of the methods for the implant surface treatment, remarkably increased surface area, enhanced wettability and accelerated the initial bone healing. Purpose: This study was performed to evaluate the wettability of anodized titanium surface which has a nanotubular structure, to assess osseointegration after the placement of implant with nano-size tubes on tibia of rats and to analyze quantitatively transferable rhBMP-2 on each surface. MATERIAL AND METHOD: Four different kinds of surface-treated titanium discs (polished (machined surface) group, micro (blasting surface) group, nano (anodizedmachined surface) group, and nano-micro (anodized-blasting surface) group) were fabricated (n=10). Three different media were chosen to measure the surface contact angles; distilled water, plasma and rhBMP-2 solution. After a single drop (0.025 ml) of solution, the picture was taken with the image camera, and contact angle was measured by using image analysis system. For the test of osseointegration, 2 kinds of anodized surface (anodized-machined surface, anodized-blasting surface) implants having 2.0 mm in diameter and 5.0 mm in length inserted into the tibia of Wistar rats. After 3 weeks, tibia were harvested and the specimens were stained with hematoxylin and eosin for histological analysis. To test the possibility of drug delivery, after soaking sample groups in the concentration of 250 ng/ml of rhBMP-2 for 48 hours, the excess solution of rhBMP-2 were removed. After that, they were lyophilized for 24 hours, and then the rhBMP-2 on the surface of titanium was resolved for 72 hours in PBS. All the extracted solution was analyzed by ELISA. One-way analysis of variance (ANOVA) was performed on the data. RESULTS: The wettability is improved by anodic oxidation. The best wettability was shown on the nano-micro group, and it was followed by nano group, micro group, and polished group. In the histological findings, all implants showed good healing and the new bone formation were observed along the implant surface. After 3 days, nano-micro group delivered the most amount of rhBMP-2, followed by nano group, micro group, and polished group. CONCLUSION: It indicated that anodic oxidation on blasting surface produce functionally graded nano-micro porous structure and enhance hydrophilicity of the surface and osseointegration. The findings suggest that the nano-micro porous structure could be a useful carrier of osteogenic molecules like rhBMP-2.
Animals ; Durapatite ; Enzyme-Linked Immunosorbent Assay ; Eosine Yellowish-(YS) ; Hematoxylin ; Hydrophobic and Hydrophilic Interactions ; Osseointegration ; Osteogenesis ; Plasma ; Rats ; Rats, Wistar ; Tibia ; Titanium ; Water ; Wettability

STATEMENT OF PROBLEM: The screws of dental implant, having various thread types, can be categorized into different classes by their geometrical form, and each type transmits dissimilar amount and form of stress to alveolar bone. PURPOSE: The purpose of this study was to find an inclination angle of the screw thread that is favorable in distributing the stresses to alveolar bone. MATERIAL AND METHODS: In this study, We used three dimensional finite element analysis with modeling having three types of thread inclination angles and fixed pitch-0.8 mm (single thread type with 3.8 degrees inclination, double thread type with 7.7 degrees inclination, triple thread type with 11.5 degrees inclination). RESULTS: The results obtained from this study were as follows; 1. When the number of thread increased, the amount of Von-Mises stress was reduced since the generated stress was effectively distributed. 2. Since the maximum principal stress affects on the alveolar bone can influence deeply on the longevity of the implants when comparing the magnitude of the maximum principal stress double thread had least amount of stress. This shows that the double thread screw gave best result. CONCLUSION: In conclusion, double, and triple thread screws were found to be more effective on distribution of the stress than the single thread screws. But, increasing in the thread inclination angle such as triple thread screw relate on the magnitude of the maximum principal stress affecting on the alveolar bone can become problematic. Thus, effective combination of thread number and thread inclination angle can help prolonging the longevity of implant.
Dental Implants ; Finite Element Analysis* ; Longevity

PURPOSE: Current trend in implant dentistry is changing from external connection to internal connection. To evaluate the splinting of external and internal connection implant on screw loosening, 2-units prosthesis was fabricated with BioPlant System(R) of external connection type and Lifecore STAGE-1 Single Stage Implant System(R) of internal connection type. MATERIAL AND METHOD: Experimental group is classified into three groups. 1) G1-EE: 2-units prosthesis was fabricated with two BioPlant System. of external connection type. 2) G1-EI: 2-units prosthesis was fabricated with one BioPlant System(R) of external connection type and one Lifecore STAGE-1 Single Stage Implant System(R) of internal connection type. 3) G1-II: 2-units prosthesis was fabricated with two Lifecore STAGE-1 Single Stage Implant System(R) of internal connection type. In fabricating 2-units prosthesis, two hexed abutments are recommended when two implants are installed parallel, otherwise one hexed abutment is used on major occlusal force area and one nonhexed abutment is used on the other area. Since it is rare to find two implants being parallel, it is hard to fabricate prosthesis with passive adaptation using two hexed abutments. It is much more difficult to acquire passive adaptation when using hex abutment compared to nonhex abutment. To evaluate the influence of hexed and nonhexed abutment on screw loosening, 2-units prosthesis was fabricated with hexed and nonhexed abutment. Experimental group is classified into three groups. 1) G2-HH: 2-units prosthesis was fabricated with two hexed abutments. 2) G2-HN: 2-units prosthesis was fabricated with one hexed abutment and one nonhexed abutment. 3) G2-NN: 2-units prosthesis was fabricated with two nonhexed abutments. RESULT: The results of comparing the detorque value after loading on a each prosthesis periodically are as follows. 1. In splinting group of external and internal connection implant, G1-II group demonstrated the biggest detorque value, followed by G1-EI group and G1-EE group. 2. There is no notable significance between external connection implant of G1-EI group and G1-EE group and also no significance between internal connection implant of G1-EI group and G1-II group. 3. G2-HH group showed higher detorque value than G2-HN and G2-NN group. From the results, we can concluded that using both external connection and internal connection implant together is clinically acceptable and in order to acquire a good passive adaptation in fabricating 2-units implant prosthesis we can use two nonhexed abutments.
Bite Force ; Dentistry ; Prostheses and Implants ; Splints

PURPOSE: The biocompatibility and bio-adhesive property of a dental implant abutment are important for proper soft tissue healing and maintenance of osseointegration of implant. However, studies of soft tissue healing and mucosal attachment of various materials of implant abutment other than titanium are still needed. In this study, cell attachment, proliferation, cytotoxicity of human gingival fibroblast for ceramic, gold alloy, Ni-Cr alloy and, commercially available pure titanium as a control were evaluated, using MTS and scanning electron microscopy. MATERIALS AND METHODS: Specimen was designed to disc, 4mm diameter and 1mm thickness, made of ceramic, gold alloy, Ni-Cr alloy and commercially available pure titanium. Primary culture of human gingival fibroblasts were grown in Dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. Cells were inoculated in the multiwell plates placed the specimen disc. Cell Titer 96 AQucous One Solution Cell Proliferation Assay were done after 1hour, 3hours, 24hours, 3days, 5days of incubation. The discs were processed for scanning electron micrography to evaluate cell attachment and morphologic change. RESULTS: The results were obtained as follows. 1. The ceramic showed high cell attachment and proliferation and low cytotoxicity, which is as much bioadhesive and biocompatible as titanium. 2. The gold alloy represented limited proliferation of human gingival fibroblast and the highest cytotoxicity among tested materials (p<0.05). 3. The Ni-Cr alloy limited the proliferaion of the human gingival fibroblast compared to titanium(p<0.05), but cytotoxicity on the bottom of well was not so considerable, compared to titanium. 4. On the scanning electron micrographs, the ceramic showed good attachment and proliferation of human gingival fibroblast, which was similar to titanium. But gold alloy and Ni-Cr alloy showed the shrinkage of gingival fibroblast both after 24 hours and 3 days. On 5th day, small amount of the human gingival fibroblast proliferation was observed on the Ni-Cr alloy, while the shrinkage of gingival fibroblast was still observed on the gold alloy. CONCLUSIONS: These results suggest that the ceramic abutment is as biocompatible as titanium to make proper mucosal seal. The gold alloy has a high cytotoxicity to limit proliferation of gingival fibroblast, which suggest limited use on the anterior tooth where soft tissue healing is recommeded.
Alloys ; Anti-Bacterial Agents ; Cell Proliferation ; Ceramics ; Dental Implants ; Fibroblasts* ; Humans* ; Microscopy, Electron, Scanning ; Osseointegration ; Titanium ; Tooth

PURPOSE: The biocompatibility and bio-adhesive property of a dental implant abutment are important for proper soft tissue healing and maintenance of osseointegration of implant. However, studies of soft tissue healing and mucosal attachment of various materials of implant abutment other than titanium are still needed. In this study, cell attachment, proliferation, cytotoxicity of human gingival fibroblast for ceramic, gold alloy, Ni-Cr alloy and, commercially available pure titanium as a control were evaluated, using MTS and scanning electron microscopy. MATERIALS AND METHODS: Specimen was designed to disc, 4mm diameter and 1mm thickness, made of ceramic, gold alloy, Ni-Cr alloy and commercially available pure titanium. Primary culture of human gingival fibroblasts were grown in Dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. Cells were inoculated in the multiwell plates placed the specimen disc. Cell Titer 96 AQucous One Solution Cell Proliferation Assay were done after 1hour, 3hours, 24hours, 3days, 5days of incubation. The discs were processed for scanning electron micrography to evaluate cell attachment and morphologic change. RESULTS: The results were obtained as follows. 1. The ceramic showed high cell attachment and proliferation and low cytotoxicity, which is as much bioadhesive and biocompatible as titanium. 2. The gold alloy represented limited proliferation of human gingival fibroblast and the highest cytotoxicity among tested materials (p<0.05). 3. The Ni-Cr alloy limited the proliferaion of the human gingival fibroblast compared to titanium(p<0.05), but cytotoxicity on the bottom of well was not so considerable, compared to titanium. 4. On the scanning electron micrographs, the ceramic showed good attachment and proliferation of human gingival fibroblast, which was similar to titanium. But gold alloy and Ni-Cr alloy showed the shrinkage of gingival fibroblast both after 24 hours and 3 days. On 5th day, small amount of the human gingival fibroblast proliferation was observed on the Ni-Cr alloy, while the shrinkage of gingival fibroblast was still observed on the gold alloy. CONCLUSIONS: These results suggest that the ceramic abutment is as biocompatible as titanium to make proper mucosal seal. The gold alloy has a high cytotoxicity to limit proliferation of gingival fibroblast, which suggest limited use on the anterior tooth where soft tissue healing is recommeded.
Alloys ; Anti-Bacterial Agents ; Cell Proliferation ; Ceramics ; Dental Implants ; Fibroblasts* ; Humans* ; Microscopy, Electron, Scanning ; Osseointegration ; Titanium ; Tooth