• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.863-875
• /
• 2005

Bovine bone-derived bone substitutes are widely used for treatment of bone defects in dental and orthopedic regenerative surgery. The purpose of this study was to evaluate the basic characteristics of deproteinized bovine bone mineral as a bone graft substitute. Commercially available products from three different bovine bone minerals-Bio-Oss(GeistlichPharma, Switzerland), BBP(Oscotec. Korea), Osteograf/N-300(Dentsply Friadent Ceramed, USA) - were investigated. They were evaluated by scanning electron microscopy(SEM), energy dispersive X-ray spectrometer(EDS), surface area analysis(BET), and Kjeldahl protein analysis. Cell viability on different products was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay. The results of this study indicated that each bone substitute displayed distinct surface properties. Furthermore, Kjeldahl protein analysis indicated that residual crude proteins are present in deproteinized bovine bone mineral. BBP showed relatively large amount of residual protein, which indicated that the possibility of disease transmission can not be safely ruled out. Based on the results of this study, it is suggested that active quality management is strongly needed in operations that involve processing bovine bone tissue for medical use.

• The Journal of Korean Academy of Prosthodontics
• /
• v.42 no.6
• /
• pp.628-640
• /
• 2004

Statement of problem. Wear as a result of repeated closing/opening cycles may decrease the friction coefficient of screw head, threads, and other mating components and, consequently, resistance to opening gradually decreases. It may cause screw loosening, which is one of the most common failures in implant prosthesis. Purpose. The purpose of this study is to evaluate the changes on the head and thread surface of the abutment screws after repeated closing and opening through the examination of tested screws in SEM(scanning electron microscope). Materials and methods. Five species of abutments were selected (3i-three, Avana-two) respectively by two pieces. The implant fixtures were perpendicularly mounted in liquid unsaturated polyesther(Epovia, Cray Valley Inc.) with dental surveyor. Each abutment was secured to the implant fixture by each abutment screw with recommended torque value using a digital torque controller. The abutment screws were repeatedly tightened and removed 20 times with a digital controller. FESEM (field emission scanning electron microscope, Netherland, Phillips co., model:XL 30 SFEG) was used to observe changes of each part caused by repeatedly closing/opening expeiment. First, the Photomicrographs of pre-test screws provided by each manufacturer were taken. The changes of each screw were investigated after every fifth closing and opening experiment with FESEM. Scaning electron microscope photomicrographs of each screw were taken four times. Results. As the number of closing and opening was increased, the wear or distortion of hexed or squared slot that contacted with the driver tip was more severely progressed. Wear or distortion of hexed slot was more severe than that of squared slot and it was more remarkable in the titanium screw than in the gold screw. All the tested screws showed that the width in the crest of their screw thread decreased gradually as the test was proceeded. Conclusions. Conclusively, we recommend the clinical use of gold screw, a periodic exchanges of abutment screws and avoiding repeated closing/opening unnecessarily. We also suggest a more careful manipulation of the abutment screw and screw-driver and using of abutment screw with an acute-angled slot design rather than an obtuse-angled one. Finally, it is suggested that the new slot design and the surface treatment for enduring wear or distortion should be devised.

• The Journal of Advanced Prosthodontics
• /
• v.7 no.2
• /
• pp.138-145
• /
• 2015

PURPOSE. The objective of this study was to conduct an in vitro comparative evaluation of polished and laser-dimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS. Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had $5-{\mu}m$ dimples at $10-{\mu}m$ intervals, and SM30 (n=16) had $5-{\mu}m$ dimples at $25-{\mu}m$ intervals in a $2{\times}4mm^2$ area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS. The adhesion strength of epithelial cells was higher on Ti surfaces with $5-{\mu}m$ laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION. These findings demonstrate that laser dimpling may contribute to improving the peri-implant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.

• Journal of Periodontal and Implant Science
• /
• v.44 no.1
• /
• pp.33-38
• /
• 2014

Purpose: Autogenous bones are frequently used because of their lack of antigenicity, but good osteoconductive and osteoinductive properties. This study evaluated the biological behavior of perforated and nonperforated cortical block bone grafts. Methods: Ten nonsmoking patients who required treatment due to severe resorption of the alveolar process and subsequent implant installation were included in the study. The inclusion criteria was loss of one or more teeth; the presence of atrophy of the alveolar process with the indication of reconstruction procedures to allow rehabilitation with dental implants; and the absence of systemic disease, local infection, or inflammation. The patients were randomly divided into two groups based on whether they received a perforated (inner surface) or nonperforated graft. After a 6-month healing period, a biopsy was performed and osseointegrated implants were installed in the same procedure. Results: Fibrous connective tissue was evident at the interface in patients who received nonperforated grafts. However, full union between the graft and host bed was visible in those who had received a perforated graft. Conclusions: We found that cortical inner side perforations at donor sites increased the surface area and opened the medullary cavity. Our results indicate an increased rate of graft incorporation in patients who received such perforated grafts.

• Journal of Korean Foot and Ankle Society
• /
• v.10 no.2
• /
• pp.218-222
• /
• 2006

Purpose: We evaluate the results of subtalar arthroereisis with $Kalix^{(R)}$ implant (Newdeal, Lyon, France) that were performed in painful flatfoot deformity. Materials and Methods: We performed the subtalar arthroereisis on 16 feet of children symptomatic flexible flat feet after more than 6 months of conservative treatment. Average age was 11 years (8-14 years) old. We checked the functional status with AOFAS functional score in pre-operatively and at final follow-up. Radiologically, we took weight bearing anterior to posterior and lateral view of the feet, and measured the talo-$1^{st}$ metatarsal angle, calcaneal pitch angle, cuboid-surface height. Finally, we asked to patient's parents for satisfaction of the surgery. Results: Mean follow up period was 34.1 months. Average AOFAS score improved from preoperatively 71.9 to postoperatively 91.3. Only one patient has subtalar pain. Average lateral $1^{st}$ metatarsal angle reduced from $-18.2^{\circ}$ preoperatively to $-4.6^{\circ}$ at final follow-up. Average anterior to posterior $1^{st}$ metatarsal angle was reduced from $18.9^{\circ}$ preoperatively to $6.5^{\circ}$ at final follow-up. Average calcaneal pitch angle was increased from $8.6^{\circ}$ preoperatively to $12.6^{\circ}$ at final follow-up. Average cuoboid-surface height was improved from 12.1 mm preoperatively to 16.0 mm at final follow-up. All patients had excellent or good satisfaction. Conclusions: Subtalar arthroereisis with $Kalix^{(R)}$ implant is a viable surgical alternative for painful flatfoot deformity of children.

• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.991-1002
• /
• 2005

The purpose of this study was to compare the effect of desensitizing agents applied on hypersensitive root surface following periodontal treatment. This study included 21 subjects(168 vital teeth). To evaluate dentin sensitivity, three clinical tests(tactile, air stream, cold water) were tried and three different densensitizing agents(MS coat, Elmex gel. Superseal) were individually applied. After application, reassessment was done at 1 minute, 1 week, 1 month and 3 months. The results were as follows : 1. The degree of dentin sensitivity was measured highly in the sequence of cold water, air stream and tactile and significantly decreased in all four groups with lapse of time(p<0.05). 2. There was no significant difference between all four groups in the tactile test with lapse of time. 3. There was no significant difference between three experimental groups in the air stream test with lapse of time. however, one minute later, it was measured highly in the sequence of Superseal, MS coat and Elmex 4. There was no significant difference between three experimental groups in the cold water test with lapse of time. As a result of this study, all of three agents were significantly effective in reducing dentin hypersensitivity and these agents could be positively employed to patients complaining of dentin hypersensitivity following periodontal treatment.

• Journal of Periodontal and Implant Science
• /
• v.36 no.1
• /
• pp.27-37
• /
• 2006

Although the main purpose of periodontal treatment to regenerate is the complete regeneration of periodontal tissue due to periodontal disease, most of the treatment cannot meet such purpose because healing by long epithelial junction. Therefore, diverse materials of resorbable and non-resorbable have been used to regenerate the periodontal tissue. Due to high risk of exposure and necessity of secondary surgical procedure when using non-resorbable membrane, guided tissue regeneration using the resorbable membrane has gain popularity, recently. However, present resorbable membrane has the disadvantage of not having sufficient time to regenerate date to the difference of resorption rate according to surgical site. Meanwhile, other than the structure stability and facile manipulation, acellular dermal matrix has been reported to be a possible scaffold for cellular proliferation due to rapid revascularization and favorable physical properties for cellular attachment and proliferation. The purpose of this study is to estimate the influence of acellular dermal matrix on periodontal ligament, cementum and alveolar bone when acellular dermal matrix is implanted to 1-wall alveolar bone defect. 4 dogs of 12 to 16 month old irrelevant to sex , which below 15Kg of body weight, has been used in this study. ADM has been used for the material of guided tissue regeneration. The 3rd premolar of the lower jaw was extracted bilaterally and awaited for self-healing. subsequently buccal and lingual flap was elevated to form one wall intrabony defect with the depth and width of 4mm on the distal surface of 2nd premolar and the mesial surface of 4th premolar. After the removal of periodontal ligament by root planing. notch was formed on the basal position. Following the root surface treatment, while the control group had the flap sutured without any treatment on surgically induced intrabony defect. Following the root surface treatment, the flap of intrabony defect was sutured with the ADM inserted while the control group sutured without any insertion. The histologic specimen was observed after 4 and 8 weeks of treatment. The control group was partially regenerated by periodontal ligament, new cementum and new alveolar bone. the level of regeneration is not reached on the previous formed notch. but, experimental group was fully regenerated by functionally oriented periodontal ligament fiber. new cementum and new alveolar bone. In conclusion, we think that ADM seems to be used by scaffold for periodontal ligament cells and the matrix is expected to use on guided tissue regeneration.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.23-23
• /
• 2018

In this study, new titanium alloys were prepared by adding elements such as tantalum (Ta), zirconium (Zr) and the like to complement the biological, chemical and mechanical properties of titanium alloys. The Ti-40Ta-xZr ternary alloy was formed on the basis of Ti-40Ta alloy with the contents of Zr in the contents of 0, 3, 7 and 15 wt. %. Plasma electrolytic oxidation (PEO), which combines high-voltage sparks and electrochemical oxidation, is a novel method to form ceramic coatings on light metals such as Ti and its alloys. These oxide film produced by the electrochemical surface treatment is a thick and uniform porous form. It is also composed of hydroxyapatite and calcium phosphate-based phases, so it has the characteristics of bone inorganic, non-toxic and very high bioactivity and biocompatibility. Ti-40Ta-xZr alloys were homogenized in an Ar atmosphere at $1050^{\circ}C$ for 1 hour and then quenched in ice water. The electrochemical oxide film was applied by using a power supply of 280 V for 3 minutes in 0.15 M calcium acetate monohydrate ($Ca(CH_3COO)_2{\cdot}H_2O$) and 0.02 M calcium glycerophosphate ($C_3H_7CaO_6P$) electrolyte. A small amount of 0.0075M zinc acetate and magnesium acetate were added to the electrolyte to enhance the bioactivity. The mechanical properties of the coated surface of Ti-40Ta-xZr alloys were evaluated by Vickers hardness, roughness test, and elastic modulus using nano-indentation, and the surface wettability was evaluated by measuring the contact angle of the coated surface. In addition, cell activation and differentiation were examined by cell culture of HEK 293 (Human embryonic kidney 293) cell proliferation. Surface properties of the alloys were analyzed by scanning electron microscopy(FE-SEM), EDS, and X-ray diffraction analysis (XRD).

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.1
• /
• pp.41-45
• /
• 2009

Background: Reduced bone height is one of the major problems faced in restoring tooth loss with implants. By the use of short implants, it is possible to reduce complicated and invasive treatment such as bone graft, allowing more simple surgery. But short implants are generally considered to have lower success rates than that of standard implants. Purpose: To assess the results of short Straumann implants by a retrospective study of short Straumann implants with TPS(titanium plasma-sprayed) and SLA(sandblasted, large grit, acid etched) surfaces. Materials and methods: 173 implants in 106 patients who received short Straumann implant surgery(${\le}8\;mm$) in the department of oral and maxillofacial surgery, Kyunghee Dental Hospital, from February 1996 to October 2006 were selected and studied. All of the implants were followed up after prosthetic rehabilitation. The average follow-up period was 34 months with 119 months as the longest follow up period. The average follow-up period after prosthetic rehabilitation was 31 months. 64 females(60.4%) and 42 males(39.6%) participated in the research with the age range of 19 to 85(mean age 47). 20 patients(18.9%) were under 40, 85 patients(80.2%) were over 40 and under 70, and only one patient(0.9%) was over 70 years old. Results: 27 implants(15.6%) had TPS surface while 146 implants(84.4%) had SLA surface. 9 implants(5.2%) were 3.3, 108 implans(62.4%) were 4.1mm and 56 implants(32.4%) were 4.8mm in diameter. 167 implants(96.5%) were 8mm and 6 implants(3.5%) were 6mm in length. There were 24 implants(13.9%) on the maxillas and 149 implants(68.8%) on the mandibles. 119 implants(68.8%) were rehabilitated with FPD(fixed partial denture), 47 implants(27.2%) with single crowns and 4 implants(2.3%) with overdentures. Among the fixed partial dentures, 30 of them were splinted with short implants only. After over an year of follow-up period, 139 implants(96.5%) out of 144 implants showed marginal bone loss of less than 1mm. 3 out of 173 implants failed showing 98.27% survival rate. Conclusions: The use of short Straumann implants(${\le}8mm$) can be a simple and reliable treatment method in minimal residual bone height.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.4
• /
• pp.308-314
• /
• 2010

Purpose: The purpose of this study is to analyze the change in re-osseointegration over time and bone reaction at the interface between implant fixture and the surface of the bone, after destroying re-osseointegration by distorting the bone-implant interface artificially. Materials and methods: Experimental implant fixtures (cp titanium, ${\phi}3.75\;mm{\times}4\;mm$) which didn't have surface treatment were produced. Two or three fixtures were implanted on both tibias of twelve female rabbits (New Zealand white, more than 3.5 kg). Then after six weeks, removal torque (RT) was measured and the results were recorded as the first measurement values. The fixtures were submerged again to get reosseointegration between the bone and fixture. To identify the change in re-osseointegration of submerged fixtures over time, six groups had the healing time for four days (group I), one week (group II), two weeks (group III), three weeks (group IV), four weeks (group V) and five weeks (group VI), and then the secondary removal torque was measured for each group. To identify the bone formation under fluorescent light, tetracycline (15 mg/kg, IM) were treated on the rabbits of each group. After the second measurement, the rabbits were sacrificed, and 16 slides were made, two or three for each group. The slides were observed under the fluorescent light with light microscope. To find out the change in the secondary removal torque over the primary removal torque in progress of time, the averages of the increase rate of the primary and secondary torque removal force were calculated. Then, to find out if there were any critical differences between the primary removal torque and the secondary removal torque in each group and among the groups, the results were analyzed statistically by paired t- test, one-way ANOVA, and Duncan's Multiple Range Test. Results: In group I and II, secondary removal torque decreased, especially in group I. In group III, IV, V, and VI, secondary removal torque increased critically. Comparing the differences among the groups, the critical difference was shown between group I, II and group III, IV, V, VI. Mineralization at the interface between the bone and implant fixture was identified from the first week, and bone formation was shown more clearly from the second week. Conclusion: If the implant fixture remains unforced for a certain period of time after the fixture has had iatrogenic mobility, re-osseointegration occurs at the surface of the fixture, and for tibias of rabbits, higher re-osseointegration was obtained within two weeks.