No abstract available.
Extracellular Matrix Proteins* ; Extracellular Matrix* ; Peptides* ; Titanium*

Osteoblast or bone marrow stromal cell-derived RANKL is the major effector molecule essential for osteoclastogenesis. Previous studies have shown that tetracyclines have beneficial therapeutic effects in the prevention and treatment of inflammatory bone disease including periodontal disease. Periodontal ligament cells are thought not only to play an important role in the progression of periodontal disease, but to play an important role in alveolar bone remodeling. Previous studies indicated that receptor activation of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) are expressed in periodontal ligament cells by pro-inflammatory cytokine, such as IL-1beta and TNF-alpha . This study was designed to investigate the inhibitory effect of doxycycline on RANKL and OPG mRNA in rat periodontal ligament cells induced by IL-1beta(1 ng/ml). The results are as follows; 1. MTT assay showed that doxycycline at the concentration of 1-50 microgram/ml didn't result in statistically significant cell death at day 1 and 3 . 2. RANKL mRNA expression was increased to 2.6 folds by IL-1beta. When cells were treated with doxycycline (50 microgram/ml), IL-1beta-induced mRANKL expression was reduced by 33%. In contrast to RANKL, OPG mRNA expression was not inhibited by pre-treatment with doxycycline. These results suggest that doxycycline decrease the expression of mRANKL resulting in regulation of osteoclastogenesis in rat periodontal ligament cells.
Rats ; Animals ; Tumor Necrosis Factor-alpha

No abstract available.
Animals ; Enzyme-Linked Immunosorbent Assay ; Fibroblasts* ; Mice* ; p38 Mitogen-Activated Protein Kinases* ; Periodontal Ligament* ; Polymerase Chain Reaction

No abstract available.
Actinobacillus* ; Aggregatibacter actinomycetemcomitans* ; Animals ; Osteoclasts ; Rats*

STATEMENT OF PROBLEM: After placing the implant on the jaw, firm osseointegration between the implant interface and the bone should be achieved so that it can perform the same function as the normal teeth. That is, stability of the implant is required in order to form firm osseointegration. PURPOSE: This study was performed to evaluate the effect of implant preparation methods on primary implant stability in various bone qualities. MATERIAL AND METHODS: The recipient sites were prepared by various methods on 4 types of wooden plates (Osstem Co., Korea) which have similar mechanical properties with 4 types of human bone quality. The groups were divided according to implant preparation methods: In the control group the recipient sites were prepared from 1.8 mm guide drill, 2.0 mm initial drill, 2.7 mm pilot drill, 2.7 mm twist drill, 3.0 mm twist drill, 3.3 mm pilot drill, 3.3 mm twist drill, countersink drill, and tapping drill sequentially and 6 RBM surfaced GSII Osstem implants (Osstem Co., Korea) were installed in each type of wooden plates; In group 1, the recipient sites were prepared from 1.8 mm guide drill to 3.0 twist drill sequentially without countersink drill nor tapping drill and implants were placed; In group 2, the recipient sites were prepared from 1.8 mm guide drill to 3.0 mm twist drill, and countersink drill sequentially without tapping drill and implants were placed; In group 3, the recipient sites were prepared from 1.8 mm guide drill to 3.0 mm twist drill, countersink drill, and tapping drill sequentially and implants were placed; In group 4, the recipient sites were prepared from 1.8 mm guide drill to 3.3 mm twist drill sequentially without countersink drill nor tapping drill and implants were placed; In group 5, the recipient sites were prepared from 1.8 mm guide drill to 3.3 mm twist drill and countersink drill sequentially without tapping drill and implants were placed; In group 6, the recipient sites were prepared with 2.0 mm twist drill and 3.0 mm osteotome and implants were placed. The insertion torque was measured by INTRA surg(R)300 (KaVo., Germany). After installation of implants, the primary implant stability was measured by using Osstell(TM), Osstell(TM) mentor, and Periotest(R), and insertion torque test. The statistical analysis of the results was analyzed using SPSS ver. 12.0. Student t-tests and one-way analysis of variance (ANOVA) were used. RESULTS: The results obtained were as follows; 1. In type I and II bone quality plates, although the mean value of primary implant stability was somewhat different according to test methods, the primary implant stability of group 1 was significantly higher than those of other groups (p<0.05). 2. In type III bone quality plate, the primary implant stability of group 1 was significantly higher than those of other groups in Osstell(TM) test, the primary stability of group 1 and group 6 were significantly higher than those of other groups in Osstell(TM) mentor and Periotest(R), and the stability of group 6 was significantly higher than those of other groups in insertion torque test (p<0.05). 3. In type IV bone quality plate, the primary implant stability of group 6 was significantly higher than those of other groups (p<0.05). 4. As the quality of bone was softer, the primary implant stability tended to be lower in values. This tendency was not significantly different in Osstell(TM) and Osstell(TM) mentor tests, but it was significantly different in insertion torque test (p<0.05). 5. In type IV bone quality plate, the mean values of primary implant stability which were calculated by Osstell(TM) was 14.8+/-8.6 higher than the values calculated by Osstell(TM) mentor. CONCLUSION: These results suggest that the recipient implant preparation by using minimal drilling and osteotome may be useful in obtaining the primary implant stability and the insertion torque test seems be the most simple and predictable method.
Humans ; Jaw ; Mentors ; Osseointegration ; Tooth ; Torque

STATEMENT OF PROBLEM: Ti-alloy has been used widely since it was produced in the United States in 1947 because it has high biocompatibility and anticorrosive characteristics. PURPOSE: The pure titanium, however, was used limitedly due to insufficient mechanical charateristics and difficult manufacturing process. Our previous study was focused on the development of a new titanium alloy. In the previous study we found that the Ti-Ta-Nb alloy had better mechanical characteristics and similar anticorrosive characteristics to Ti-6Al-4V. MATERIAL AND METHODS: In this study, the cytotoxicity of the Ti-Ta-Nb alloy was evaluated by MTT assay using MSCs(Mesenchaimal stem cells) and L929 cells(fibroblast cell line). The biocompatibility of the Ti-Ta-Nb alloy was performed by inserting the alloy into the femur of the rabbits and observing the radiological and histological changes surrounding the alloy implant. RESULTS: 1. In the cytotoxicity test using MSCs, the 60% survival rate was observed in pure titanium, 84% in Ti-6Al-4V alloy, and 95% in Ti-10Ta-10Nb alloy. 2. In the animal study, the serial follow-up of the radiographs showed no separation or migration revealing gradual bone ingrowth surrounding the implants. Similar radiographic results were obtained among three implant groups: pure titanium, Ti-6Al-4V alloy and Ti-10Ta-10Nb alloy. 3. In the histologic examination of the bone block containing the implants. the bone ingrowth was prominent around the implants with the lapse of time. There was no signs of any tissue rejection, degeneration, or inflammation. Active bone ingrowth was observed around the implants. In the comparison of the three groups, the rate of bone ingrowth was better in the Ti-10Ta-10Nb alloy group than those in pure titanium group or Ti-6Al-4V alloy group. In conclusion, Ti-10Ta-10Nb alloy revealed better biocompatibility in survival rate of the cells and bone ingrowth around the implants. Therefore we believe a newly developed Ti-10Ta-10Nb alloy can replace currently used Ti-6Al-4V alloy to increase biocompatibility and to decrease side effects. CONCLUSION: In conclusion, Ti-10Ta-10Nb alloy revealed better biocompatibility in survival rate of the cells and bone ingrowth around the implants. Therefore we believe a newly developed Ti-10Ta-10Nb alloy can replace currently used Ti-6Al-4V alloy to increase biocompatibility and to decrease side effects.
Alloys* ; Animals ; Femur ; Follow-Up Studies ; Inflammation ; Rabbits ; Survival Rate ; Titanium ; United States

No abstract available.
Alloys* ; Animals ; Rats*

No abstract available.
Animals ; Periodontal Ligament* ; Phosphotransferases* ; Rats*

PURPOSE: The characteristics of oxidized titanium (Ti) surfaces varied according to treatment conditions such as duration time and temperature. Thermal oxidation can change Ti surface characteristics, which affect many cellular responses such as cell adhesion, proliferation, and differentiation. Thus, this study was conducted to evaluate the surface characteristics and cell response of thermally treated Ti surfaces. METHODS: The samples were divided into 4 groups. Control: machined smooth titanium (Ti-S) was untreated. Group I: Ti-S was treated in a furnace at 300degrees C for 30 minutes. Group II: Ti-S was treated at 500degrees C for 30 minutes. Group III: Ti-S was treated at 750degrees C for 30 minutes. A scanning electron microscope, atomic force microscope, and X-ray diffraction were used to assess surface characteristics and chemical composition. The water contact angle and surface energy were measured to assess physical properties. RESULTS: The titanium dioxide (TiO2) thickness increased as the treatment temperature increased. Additional peaks belonging to rutile TiO2 were only found in group III. The contact angle in group III was significantly lower than any of the other groups. The surface energy significantly increased as the treatment temperature increased, especially in group III. In the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, after 24 hours of incubation, the assessment of cell viability showed that the optical density of the control had a higher tendency than any other group, but there was no significant difference. However, the alkaline phosphatase activity increased as the temperature increased, especially in group III. CONCLUSIONS: Consequently, the surface characteristics and biocompatibility increased as the temperature increased. This indicates that surface modification by thermal treatment could be another useful method for medical and dental implants.
Alkaline Phosphatase ; Cell Adhesion ; Cell Survival ; Dental Implants ; Electrons ; Phase Transition ; Tetrazolium Salts ; Thiazoles ; Titanium ; Transition Temperature ; Water ; Wettability ; X-Ray Diffraction

OBJECTIVETo evaluate the effect of electromagnetic pulse (EMP) irradiation on mice reproduction.

METHODSFemale/male Kunming mice, 6 - 8 weeks old, prior to mating, or female after pregnancy were treated with whole body irradiation by 6 x 10(4) V/m electromagnetic pulse (EMP) for five times. The pregnant mice were killed on the 18th days, and teratological markers were analysed.

RESULTSEMP irradiation caused no significant changes in most of female organ weight and organ/body weight ratio. But it caused significant shortening in tail length of live foetus in the female mice before conception (prior to mating) or after pregnancy (P < 0.05), and obvious decrease in male offspring ratio (0.85 +/- 0.09 vs 1.09 +/- 0.17, P < 0.05). The male offspring ratio also significantly decreased (0.76 +/- 0.18 vs 1.09 +/- 0.17, P < 0.01) after male mice irradiated by EMP. The tail length of live foetus was shortened and male offspring sex ratio was increased after both male and female mice were irradiated by EMP. EMP irradiation also caused a significantly higher fetal death rate than normal control (P < 0.05). The embryo absorption rate was increased after irradiation except that was decreased in male mice.

CONCLUSIONEMP irradiation has effect on pregnancy and offspring development in both male and female mice before mating and in female mice after pregnancy.

Animals ; Female ; Fetus ; radiation effects ; Male ; Mice ; Pregnancy ; Radiation ; Reproduction ; radiation effects