• The Journal of Advanced Prosthodontics
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• v.1 no.2
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• pp.107-112
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• 2009

STATEMENT OF PROBLEM. Macroscopic and especially microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Dental implants with modified surfaces have shown stronger osseointegration than implants which are only turned (machined). Advanced surface modification techniques such as anodic oxidation and Ca-P application have been developed to achieve faster and stronger bonding between the host bone and the implant. PURPOSE. The purpose of this study was to investigate the effect of surface treatment of titanium dental implant on implant stability after insertion using the rabbit tibia model. MATERIAL AND METHODS. Three test groups were prepared: sandblasted, large-grit and acid-etched (SLA) implants, anodic oxidized implants, and anodized implants with Ca-P immersion. The turned implants served as control. Twenty rabbits received 80 implants in the tibia. Resonance frequencies were measured at the time of implant insertion, 2 weeks and 4 weeks of healing. Removal torque values (RTV) were measured 2 and 4 weeks after insertion. RESULTS. The implant stability quotient (ISQ) values of implants for resonance frequency analysis (RFA) increased significantly (P <. 05) during 2 weeks of healing period although there were no significant differences among the test and control groups (P >. 05). The test and control implants also showed significantly higher ISQ values during 4 weeks of healing period (P < .05). No significant differences, however, were found among all the groups. All the groups showed no significant differences in ISQ values between 2 and 4 weeks after implant insertion (P >. 05). The SLA, anodized and Ca-P immersed implants showed higher RTVs at 2 and 4 weeks of healing than the machined one (P < .05). However, there was no significant difference among the experimental groups. CONCLUSION. The surface-modified implants appear to provide superior implant stability to the turned one. Under the limitation of this study, however, we suggest that neither anodic oxidation nor Ca-P immersion techniques have any advantage over the conventional SLA technique with respect to implant stability.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.362-374
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• 2007

Statement of problem. The intial stability for osseointegration of implant has been an interesting factor. Especially, in the case of poor bone quality or immediately loaded implant, various strategies have been developed focusing on the surface of materials to improve implant fixation to bone. The microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Purpose. The aims of this study are to perform a histologic and histomorphometric comparison of the healing characteristics of three different surfaces and the comparison of resonance frequency analysis (RFA) values measured by $Osstell^{TM}$ and perio-test values (PTV) measured by Periotest. Material and methods. A total of 24 screw titanium implants (Dentium Co., Seoul, Korea) with 6mm in length and 3.4mm in diameter, were placed in the mandible of 4 beagle dogs. Implants were divided into three groups following the surface treatment methods: Group I is machined(control group). Group II is anodically oxidized. Group III is coated 500nm in thickness with hydroxyapatite(HA) by ion beam assisted deposition(IBAD) on the anodized oxidization. Bone blocks from 2 dogs were caught after 3 weeks of covered healing and another blocks from 2 dogs after 6 weeks. RFA values and PTV were measured right after insertion and at 3 and 6weeks. Histomorphometric analysis was made with Kappa Image Base System to calculate bone-to-implant contact (BIC) and bone area inside the threads. Pearson's correlation analyses were performed to evaluate the correlation between RFA and PTV, BIC and bone area ratio of three different surfaces at 3 and 6 weeks. Results. 1) In all surface treatment methods, the RFA values decreased and the PTV values increased until 6 weeks in comparison to initial values. 2) At 3 weeks, no significant difference was found from bone-to-implant contact ratio and bone area ratio of three different surface treatment methods(P>0.05). However, at 6 weeks, different surface treatment methods showed significantly different bone-toimplant contact ratio and bone area ratio(P<0.05). 3) In the implants with the IBAD on the anodic oxidization, significant difference was found between the 3 weeks and the 6 weeks bone area ratio(P<0.05). 4) Correlation was found between the RFA values and the bone area ratio at 3 and 6 weeks with significant difference(P<0.05). Conclusions. These results indicate that the implants with the IBAD on the anodic oxidization may have a high influence on the initial stability of implant.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.245-253
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• 2011

Purpose: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. Materials and methods: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). Results: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). Conclusion: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.5
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• pp.240-246
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• 2002

$TiO_2$ films on soda-lime-silica glasses were prepared by spin coating-pyrolysis process using titanium naphthenate as a starting material. As-deposited films were pyrolyzed at $500^{\circ}C$ for 10 min in air and annealed at 500, 550 and $600^{\circ}C$ for 30 min in air. Crystallinity of the film was investigated by X-ray diffraction analysis. A field emission-scanning electron microscope and an atomic force microscope were used for characterizing the surface morphology and the surface roughness of the film. After annealing at 550 and $600^{\circ}C$, the X-ray diffraction patterns consist of only anatase peak. Films annealed at 500 and $550^{\circ}C$ exhibited flat surfaces. While with the increase in annealing temperature to $600^{\circ}C$, the $TiO_2$ film showed abnormal growth of three-dimensional needle-shaped grains. For all samples, high transmittance, above 90 % at 500 nm, was obtained at visible range. To investigate photocatalytic properties, IR absorbance associated with the C-H stretching vibrations of a thin solution-cast film of stearic acid under 365 nm (2.4 mW/$\textrm{cm}^2$) UV irradiation was estimated.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.233-240
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• 2014

PURPOSE. To evaluate the effects of different abutment geometries in combination with varying luting agents and the effectiveness of different cleaning methods (prior to re-cementation) regarding the retentiveness of zirconia copings on implants. MATERIALS AND METHODS. Implants were embedded in resin blocks. Three groups of titanium abutments (pre-fabricated, height: 7.5 mm, taper: $5.7^{\circ}$; customized-long, height: 6.79 mm, taper: $4.8^{\circ}$; customized-short, height: 4.31 mm, taper: $4.8^{\circ}$) were used for luting of CAD/CAM-fabricated zirconia copings with a semi-permanent (Telio CS) and a provisional cement (TempBond NE). Retention forces were evaluated using a universal testing machine. Furthermore, the influence of cleaning methods (manually, manually in combination with ultrasonic bath or sandblasting) prior to re-cementation with a provisional cement (TempBond NE) was investigated with the pre-fabricated titanium abutments (height: 7.5 mm, taper: $5.7^{\circ}$) and SEM-analysis of inner surfaces of the copings was performed. Significant differences were determined via two-way ANOVA. RESULTS. Significant interactions between abutment geometry and luting agent were observed. TempBond NE showed the highest level of retentiveness on customized-long abutments, but was negatively affected by other abutment geometries. In contrast, luting with Telio CS demonstrated consistent results irrespective of the varying abutment geometries. Manual cleaning in combination with an ultrasonic bath was the only cleaning method tested prior to re-cementation that revealed retentiveness levels not inferior to primary cementation. CONCLUSION. No superiority for one of the two cements could be demonstrated because their influences on retentive strength are also depending on abutment geometry. Only manual cleaning in combination with an ultrasonic bath offers retentiveness levels after re-cementation comparable to those of primary luting.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.212-234
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• 1999

Dental restorative materials must have the physical properties to withstand wear and corrosion. Base metal alloys possess better mechanical properties and lower price than the gold alloys. For these reasons such alloys have largely replaced the precious metal alloys. One aspect to con-sider is the release of metal substances to oral environment. The release of elements from dental alloys is a continuing concern because the elements may have the potentially harmful biological effects on local tissues. The purpose of this study was to minimize metal release on the nonprecious metal surfaces by ion beam assisted deposition(IBAD) of titanium nitride (TiN) Ni-Cr-Be alloys with and without TiN coatings were secured in an wear test machine opposing ruby ball to determine their relative resistance to wear with loom, 200m, 300m and 400m sliding distance. And the corrosion behavior of the Ni-Cr-Be alloys with and without TiN coatings and 3 dental noble alloys have been studied. Potentiodynamic curves were used to analyse the corrosion characteristics of the alloys. The measurement of the released Ni and Cr ions was conducted by analysis of the electrolyte solution with atomic absorption spectroscopy. The results were as follows : 1. The critical sliding distance that wore down TiN coatings of $2.5{\mu}m$ thickness in this study condition was 300m. 2. Ion beam assisted deposition of TiN showed a good surface modification with respect to the properties of wear and corrosion resistance. 3. X-ray diffraction showed that the strongest peak of TiN is TiN(111) in the coatings. 4. The release of Ni and Cr ions from alloys measured by means of atomic absorption spectroscopy was reduced by ion beam assisted deposition of TiN.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.128-135
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• 2003

Statement of problem : Implant screw loosening remains a problem in implant prosthodontics. Some abutment screws with treated surfaces were introduced to prevent screw loosening and to increase preload. DLC(Diamond Like Carbon) film has similar properties on hardness, wear resistance, chemical stability, biocompatibility as real diamond materials. Purpose : The purpose of this study was to investigate the effect of lubricant layer on abutment screw and to discriminate more effective method between soft lubricant and hard lubricant to prevent screw loosening. Material and method : In this study, $1{\mu}m$ thickness DLC was used as protective, lubricating layer of titanium screws and 3 times removal torque was measured on the abutment screws to investigate the difference in 10 coated and 10 non-coated abutment screws. Results : The results indicated that the implants with DLC coating group were not more resistant to the applied force in screw loosening. At 32Ncm, the 3 times removal torque in DLC group were $27.75{\pm}2.89,\;25.85{\pm}2.35$ and $26.2{\pm}2.57$. The removal torque in no-coated abutment screws were $27.85{\pm}4.23,\;27.35{\pm}2.81$ and $27.9{\pm}2.31$, respectively. Conclusion : The lubricant layer used in this study was Diamond Like Carbon(DLC) and it have a properties of hard and stable layer. The DLC coating layer was hard enough to prevent distortion of screws in the repeated unscrewing procedure in clinical situation. The reduced friction coefficient in hard DLC layer was not effective to prevent screw loosening.

• Journal of Periodontal and Implant Science
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• v.30 no.3
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• pp.491-504
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• 2000

In clinical therapy, the current goal of dental implants is to enhance quantity and quality of osseointegration. Surface roughness and oxide structure are considered to influence the behavior of adherent cells. The purpose of this study is to evaluate the effect of different surface treatment on cellular response. The attachment and proliferation of osteoblast-like cell on sandblasted, sandblasted and etched, thermal oxidated surfaces have been compared. Sandblasting was done with $Al_2O_3$ particles(grain size of $50{\mu}m$), etching was processed with $NH_4OH$ : $H_2O_2$ : $H_2O(1:1:5)$ at $90^{\circ}C$ for 1 minute. Thermal oxidation was followed sandblasting and etching at $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$ for 2 hours. Measurement of surface roughness after the different treatment did not show any differences of Ra value between terated surfaces. Cell attachment and proliferation were increased during experiment period, but no difference was observed. SEM evaluation revealed a similar pattern of osteoblast-like cells, well attached with dendritic extension and producing numerous matrix vesicles on cell surface. The results of this study showed that oxide layer alteration by thermal oxidation did not affect the attachment and proliferation of osteoblast-like cells. This suggests the possibility that the cellular responses are further influenced by surface roughness than titaniun oxide structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.230-236
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• 2019

Recently, issues related to the quality of concrete have continuously resulted in surface quality problems, such as the exfoliation of concrete surfaces due to the cost reduction of cement and poor quality fine aggregate, scaling of surfaces caused by laitance, and plastic shrinkage cracks. Prompted by social issues, the application of a photo catalyst to road structures is being attempted to solve the environmental problems caused by fine dust and automobile exhaust. In this study, chemical admixtures were developed to improve the surface quality of concrete and to apply and distribute titanium dioxide in nanoscale sizes to provide basic data for the development of a photocatalyst-curing agent. As a result of the experiment, silicon and silane were reviewed as a raw material as a curing agent to develop a high performance curing agent with better film performance than conventional curing agents because they could form a film quickly on a fresh concrete surface. The distributed stability of the ultrasonic disperser showed the best performance through an outdoor test for four weeks to review the dispersion measures for the application of nanomaterials.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.335-341
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• 2019

Purpose: Chemically strong-acids (HF and $HCl/H_2SO_4$) dual etching implant surfaces have higher strengths of osseointegration than machined implant surfaces. However, the dual acid treatment deteriorates the physical properties of the titanium by weakening the fatigue resistance of the implant and causing microcracks. The removal torque comparison between the dual-acid etched (hydrochloric acid, sulfuric acid, HS) and single-acid etched implants (hydrochloric acid, H) could reveal the efficiency of implant surface acid treatment. Materials and methods: Nine $3.75{\times}4mm$ dual-acid etched SLA implants and nine single-acid etched SLA implants were inserted into New Zealand rabbit tibias. After 10 days, removal torque, roughness, and wetting angle were measured. Results: Mean removal torque values were as follows: Mean removal torque were 9.94 Ncm for HS group and 9.96 Ncm for H group (P=.995). Mean surface roughness value were $0.93{\mu}m$ for HS group and $0.84{\mu}m$ for H group (P=.170). Root mean square roughness (RSq) values were $1.21{\mu}m$ for HS group and $1.08{\mu}m$ for H group (P=.294), and mean wetting angle values were $99^{\circ}$ for HS group and $98^{\circ}$ for H group (P=.829). Statistical analysis showed no significant difference between the removal torques, roughness, or wetting angles of the two groups. Conclusion: In this experiment, we found no significant difference in removal torque, roughness, or wetting angle between dual-acid etched and single-acid etched implants.