• Journal of Periodontal and Implant Science
• /
• v.38 no.sup2
• /
• pp.363-372
• /
• 2008

Purpose: This study compared the effects of coating implants with hydroxyapatite (HA) using an ion beam-assisted deposition (IBAD) method prepared with machined, anodized, sandblasted and large-grit acid etched (SLA) surfaces in minipigs, and verified the excellency of coating method with HA using IBAD. Material and Methods: 4 male Minipigs(Prestige World Genetics, Korea), 18 to 24 months old and weighing approximately 35 to 40 kg, were chosen. All premolars and first molars of the maxilla were carefully extracted on each side. The implants were placed on the right side after an 8 week healing period. The implant stability was assessed by resonance frequency analysis (RFA) at the time of placement. 40 implants were divided into 5 groups; machined, anodized, anodized plus IBAD, SLA, and SLA plus IBAD surface implants. 4 weeks after implantation on the right side, the same surface implants were placed on the left side. After 4 weeks of healing, the minipigs were sacrificed and the implants were analyzed by RFA, histology and histometric. Results: RFA showed a mean implant stability quotient (ISQ) of $75.625{\pm}5.021$, $76.125{\pm}3.739$ ISQ and $77.941{\pm}2.947$ at placement, after 4 weeks healing and after 8 weeks, respectively. Histological analysis of the implants demonstrated newly formed, compact, mature cortical bone with a nearby marrow spaces. HA coating was not separated from the HA coated implant surfaces using IBAD. In particular, the SLA implants coated with HA using IBAD showed better contact osteogenesis. Statistical and histometric analysis showed no significant differences in the bone to implant contact and bone density among 5 tested surfaces. Conclusion: We can conclude that rough surface implants coated with HA by IBAD are more biocompatible, and clinical, histological, and histometric analysis showed no differences when compared with the other established implant surfaces in normal bone.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.3
• /
• pp.224-235
• /
• 2013

A passively fitting prosthesis is an essential prerequisite to attain long-lasting success and maintenance of osseointegration. However, true "passive fit" can not be achieved with the present implant-supported prosthesis fabrication protocol. Many clinical situations are suitably treated with cantilevered implant-supported fixed restorations. The purpose of this study was to compare the stress distribution pattern and magnitude in supporting tissues around ITI implants with cantilevered, implant-supported, screw-retained fixed prosthesis according to the fitness of superstructures. Photoelastic model was made with PL-2 resin (Measurements, Raleigh, USA) and three ITI implants (${\phi}4.1{\times}10mm$) were placed in the mandibular posterior edentulous area distal to the canine. Anterior and posterior extended 4-unit cantilevered FPDs were made with different misfit in the superstructures. 4 types of prosthesis were made by placing a $100{\mu}m$ gap between the abutment and the crown on the second premolar and/or the first molar. Photoelastic stress analysis were carried out to measure the fringe order around the implant supporting structure under simulated loading conditions (30 lb).

• The Journal of Korean Academy of Prosthodontics
• /
• v.43 no.2
• /
• pp.248-257
• /
• 2005

Statement of problem. Cortical bone plays an important role in the primary implant stability, which is essential to immediate/early loading. However, immediate load-bearing capacity and primary implant stability according to the change of the cortical bone thickness have not been reported. Purpose. The objectives of this study were (1) to measure the immediate load-bearing capacity of implant and primary implant stability according to the change of cortical bone thickness, and (2) to evaluate the correlation between them. Material and methods.48, screw-shaped implants (3.75 mm$\times$7 mm) were placed into bovine rib bone blocks with different upper cortical bone thickness (0-2.5 mm) and resonance frequency (RF) values were measured subsequently. After fastening of healing abutment. implants were subjected to a compressive load until tolerated micromotion threshold known for the osseointegration and load values at threshold were recorded. Thereafter, RF measurement after loading, CT taking and image analysis were performed serially to evaluate the cortical bone quality and quantity. Immediate load-bearing capacity and RF values were analyzed statistically with ANOVA and post-hoc method at 95% confidence level (P<0.05). Regression analysis and correlation test were also performed. Results. Existence and increase of cortical bone thickness increased the immediate load-bearing capacity and RF value (P<0.05) With the result of regression analysis, all parameter's of cortical bone thickness to immediate load-bearing capacity and resonance frequency showed significant positive values (P<0.0001). A significant high correlation was observed between the cortical bone thickness and immediate load-beating capacity (r=0.706, P<0.0001), between the cortical bone thickness and resonance frequency (r=0.753, P<0.0001) and between the immediate load-bearing capacity and resonance frequency (r=0.755, P<0.0001). Conclusion. In summary, cortical bone thickness change affected the immediate load-baring capacity and the RF value. Although RF analysis (RFA) is based on the measurement of implant/bone interfacial stiffness, when the implant is inserted stably, RFA is also considered to reflect implant/bone interfacial strength of immediately after placement from high correlation with the immediate load-baring capacity. RFA and measuring the cortical bone thickness with X-ray before and during surgery could be an effective diagnosis tool for the success of immediate loading of implant.

• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.813-822
• /
• 2005

The predictable outcome of implant placement in the atrophic maxilla with sinus floor elevation procedure(osteotome sinus floor elevation technique and window opening technique) is well documented. Aim of this study was to evaluate the efficacy of $Br{\aa}nemark$ Ti-Unite implant system and ITI SLA implant system placed in the atrophic posterior maxilla with sinus floor elevation procedure. Eighty patients received placement of $Br{\aa}nemark$ Ti-Unite implants(195 implants) in their atrophic posterior Maxilla with sinus floor elevation procedure(153 osteotome sinus floor elevation technique and 42 window opening procedure). Fifty patients received placement of ITI SLA implants(83 implants) in their atrophic posterior Maxilla with sinus floor elevation procedure(77 osteotome sinus floor elevation technique and 6 window opening procedure). Chart review were taken from each patient. The total failed implants were seven and the total implant survival rate was 96.4% in $Br{\aa}nemark$ Ti-Unite system. The total failed implants were one and the total implant survival rate was 98.8% in ITI SLA system. The implant survival rate with osteotome technique was 96% and 97.6% with window opening in $Br{\aa}nemark$ Ti-Unite system. The implant survival rate with osteotome technique was 98.7% and 100% with window opening. The implant survival rate with osteotome technique was 96% and 97.6% with window opening in ITI SLA system. The results of this evaluation show that the placement of $Br{\aa}nemark$ Ti-Unite system as well as ITI SLA system is a reasonable treatment option for patients with the atrophic posterior maxillary area.

• The Journal of Advanced Prosthodontics
• /
• v.1 no.2
• /
• pp.107-112
• /
• 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
• /
• v.45 no.3
• /
• pp.362-374
• /
• 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.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.31 no.3
• /
• pp.203-211
• /
• 2015

Purpose: The purpose of this study was to investigate the reosseointegration periods when the rough surface implants, which had complete bone-implant ankylosis, suddenly losed the osseointegration. Materials and Methods: The implants with RBM surface treatment were inserted into both tibias of 23 rabbits. Two implants were submerged into each side. After six weeks, the primary removal torque was measured by Digital torque gauge, and then the implants were replaced and submerged to estimate the level of reosseointegration. After assigned healing periods for each group, the removal torque was measured again. BIC (Bone-Implant contact, %) ratio was measured through histomorphometric analysis.Paired t-test was processed by SPSS 14.0. One-way ANOVA and Tukey's post-hoc test was processed to analyze statistically significant differences among the groups. Results: In comparison with the primary removal torque, the secondary removal torque was increased after 11 days and significantly increased from 2 weeks. In fluorochrome labeling, the origin of mineralization was observed after 7 days, which showed as fluorescent bands around the bone-implant interfaces. After 11 days, the bone formation was apparent, and it is increased continuously with the passage of the time. Conclusion: In 11 days after the implant replacement, the secondary removal torque was almost as same as the primary value, and was significantly higher from 2 weeks. The mineralized shapes were observed in 7 days after the implant replacement, and then the bone formation appeared visibly in 11 days.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.2
• /
• pp.141-151
• /
• 2013

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.28 no.5
• /
• pp.434-444
• /
• 2006

This study was performed to evaluate the effects of three different implant surface treatments to the bone formation during osseous healing period under unloading conditions. Machined, double-acid etched and anodic oxidized implants were inserted into tibia of 3.0 - 3.5 kg NZ white male rabbits and 2 animals of each group were sacrificed at 2, 4 and 8 weeks. The specimens containing implant was dehydrated and embedded into hard methylmethacrylate plastic. After grinding to $50{\mu}m$, the specimens were stained with Villanueva bone stain. From each specimen, histomorphometric evaluation and the bone implant contact rate were analysed with optical microscope. The results were as follows; 1. In the scanning electronic microscopic examination, machined surface implant had several shallow and paralleled scratches on plain surface, double acid-etched implant had lots of minute wrinkles, rough valley and also irregularly located craters that looked like waves, anodic oxidized surface implant had porosity that minute holes were wholly distributed on the surface. 2. After 2 weeks of implantation, the percentages of bone-to-implant contact in the machined implant, double acid-etched implant and anodic oxidized implant were 26.85%, 62.64% and 59.82%, after 4 weeks of implantation they were 64.29%, 77.85% and 75.23%, and after 8 weeks they were 82.66%, 85.34% and 86.39%. 3. After 2 weeks of implantation, the percentages of bone area between threads in the machined implant, double acid-etched implant and anodic oxidized implant were 21.55%, 42.81%, and 40.33%, after 4 weeks of implantation they were 49.32%, 62.60% and 75.56%, and after 8 weeks they were 71.62%, 87.73% and 83.94%. In summary, percentages of implant surface contacted to bone trabeculae and bone formation area inside threads in double acid-etched implants and anodic oxidized implants were greater than machined implants in early healing stage. These results suggest that double acid-etched and anodic oxidized surface implants could reduce the healing period for osseointegration and may enable to do early function.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.22 no.3
• /
• pp.274-287
• /
• 2000

The use of dental implants has increased tremendously in recent years and is expected to increase even more in the future. The successful outcome of any implant procedure is surely dependent on interrelationship of the various components of an equation that includes biocompatibility of implant material, macroscopic and microscopic nature of the implant surface, the status of implant bed, surgical technique, undisturbed healing phase and subsequent prosthetic design and long-term loading phase. The purpose of this study was to clarify the effects of adrenalectomy on the osseointegration of pure titanium implants. Seventy rats, 11 weeks of age, were divided into two groups : an adrenalectomized group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm) was placed into left tibia of 70 rats, 35 in control group and 35 in the experimental group. The rats were sacrificed at different time interval (1, 2, 3, 4, 6, 8, and 12 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with fibronectin and CD44 antibody. The results obtained from this study were as follows: 1. Histopathogically, findings, newly formed bone was seen at 3 weeks control group and became lamellar bone at 12 weeks. At 6 weeks, lipocytes were observed in bone marrow space. Thickness of regenerated trabecular bone increased till 6 weeks after then, that decreased gradually. 2. By histomorphometric analysis, marrow bone density and contact ratio of marrow bone to implant decreased significantly from 8 to 12 weeks in experimental group compared to control group and also total bone to implant contact ratio decreased significantly from 4 to 12 weeks in experimental group compared to control group. 3. Fibronectin immunoreactivity was very strong at 3 and 4 weeks control group. And after that reduced gradually. But it was continuously strong from 1 to 12 weeks experimental group. 4. CD44 immunoreactivity was very strong in the newly formed osteoblasts at 3 and 4 weeks control group. But it reacted minimally later. However, it reacted continuously strong from 3 to 12 weeks experimental group. From these results, bone to implant contact ratio decreased gradually from 4 weeks in adrenalectomized group compared to control group. CD44 and fibronectin immunoreactivities were strong at all times in adrenalectomized rats. Therefore, it could be stated that immature bone remained continuously for a long time and not readily proceeded into mature status.