• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.91-102
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• 2003

This study was performed to investigate the effect of immediate orthodontic force on soft md hard tissues surrounding C-Palatal $Plate^{TM}$ in beagle Dog. Immediately after this appliance was implanted on the midpalate of 4 adult beagle Dogs, 400gm continuous orthodontic force was applied. Experimental animals were euthanized at 8weeks, 18weeks, and 22weeks (including post-removal healing time of 4weeks), and a control animal was euthanized at 8weeks after implantation without orthodontic force application. The appliance and the surrounding tissue were studied radiographically, macroscopically, and histologically. The results were as follows: 1. The lateral radiographs taken after euthanasia showed very slight displacement of the vortical plate in the experimental animals, compared with the control animal. Mobility test of all animals confirmed primary stability without any increase of mobility during experimental period. 2. No pathologic changes were found in the healing condition of covering soft tissue and bone-screw interface in experimental animals as well as a control animal. 3. Osseointegration was achieved in the bone-screw interface in 8weeks after implantation and the amount of osseointegration increased in 18weeks. There was little difference of osseointegration between the compression side and the tension side. 4. In the marginal bone area, slight bone apposition and resorption were found regardless of compression and tension side, while there was no change in the control animal. 5. Both 8week-animal and 18week-animal showed the new bone apposition along the surface of screws which were perforated into the nasal cavity, while the control animal showed no change. 6. After 4weeks of plate removal, the covering epithelium was repaired intactly, while the connective tissue showed loose and irregular rearrangement and the connective tissue capsule remained. The C-Palatal $Plate^{TM}$ manifested sufficient anchorage capacity in the context of histological study as well as clinical outcomes, when immediate orthodontic force was applied after implantation.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.278-288
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• 2014

Purpose: The aim of the study was to evaluate preprosthetic initial survival rate and factors associated with survival of osseointegrated implants placed in edentulous area of maxilla and mandible and to suspect the possible causes leading to failure. Materials and Methods: A total of 2158 endosseous implants that had been inserted between 2004 through 2013 were placed in 770 patients. The clinical comparisons were performed to evaluate implant loss in relation to age and gender of patients, position, system, length and diameter of implant, and bone graft technique. Results: According to position, the survival rates were 98.23% in maxillary anterior site, 96.98% in maxillary posterior site, 97.85% in mandibular anterior site and 98.76% in mandibular posterior site (P < 0.05). According to diameter of implant, the survival rates were 100% under 3.0 mm, 97.09% between 3.0 to 3.5 mm, 98.19% between 3.5 to 4.0 mm and 98.29% between 4.0 to 4.5 mm but relatively lower survival rate was 75% in 5.0 mm-over (P < 0.05). The survival rates of implants were 89.51%, 98.28%, 98.34% and 99.27% in the group with isolated sinus graft, with isolated GBR, with sinus graft and GBR simultaneously and without bone graft, especially (P < 0.05). Conclusion: This study establishes a relationship between survival rate of implant and position, diameter of implant system and bone graft technique. In conclusion, there were low survival rates in maxillary posterior site, in dental implants with wide diameter of 5 mm-over, and in the group with isolated sinus graft.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.1
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• pp.31-41
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• 2008

Statement of problem: It has been proved that Pleurotus eryngii Quel and Eleutherococcus senticosus have antiinflammatory action and not only stimulates the proliferation and activity of osteoblast but inhibits the generation and activity of osteoclast in vitro. Pleurotus eryngii Quel and Eleutherococcus senticosus are the main component of $OPB-K^{(R)}$. Purpose: The purpose of this study was to evaluate $OPB-K^{(R)}$ which enhances the healing rate of peri-implant bone and the bone mineral density. Materials and methods: Thirty six specially designed implants were installed in the tibia of rats. The group medicated with $OPB-K^{(R)}$ was the experimental group, and that without was the control group. hen the implant stability was measured by $Periotest^{(R)}$. Bone mineral density and histological measurement were conducted at the 2nd, 4th and 6th week $Periotest^{(R)}$ and bone mineral density values were analyzed statistically with independent t-test at 95% confidence level(p<0.05). Results: The results of this study were as follows : 1. There was no statistically significant difference in $Periotest^{(R)}$. values between the experimental group and control group at the 2nd week, however, on the 4th and 6th week there was significant difference(p<0.05). 2. There was no statistically significant difference in bone mineral density between the experimental group and control group at the 2nd and 4th week, however on the 6th week there was significant difference(p<0.05). 3. Histological analysis showed difference in osseointegration on the 4th and 6th week between the groups. Conclusion: From the results, it is concluded that the $OPB-K^{(R)}$ medicated group showed statistically better results in bone density and stability than the control group. Clinically it would be better to medicate $OPB-K^{(R)}$ to patients for a long period of time after implantation to get superior results.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.190-198
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• 2013

Purpose: The purposes of this study were to investigate osseointegration around zirconia implants which had machined or alumina sandblasted surface, and to compare the results with titanium implants. Materials and methods: The study was performed on the tibia of 6 pigs. Three types of implants were investigated: group T-titanium implant, group Z-machined zirconia implant, group ZS-alumina sandblasting treated zirconia implant. Zirconia implants were manufactured from yttria-stabilized tetragonal zirconia polycrystalline (Acucera Inc., Pocheon, Korea). A total of 36 implants were installed in pigs' tibias. After 1, 4 and 12 weeks of healing period, the periotest and the histomorphometric analysis were performed. The data were analyzed using one-way ANOVA and significance was assessed by the Scheffe test (${\alpha}=.05$). Results: In the measurement of surface roughness, highest Ra value was measured in group T with significant difference. No significant differences were found among groups regarding Periotest values. After 1 week, in comparison of bone to implant contact (BIC), group Z showed higher value with significant difference. In comparison of bone area (BA), group T and group Z showed higher value with significant difference than group ZS. After 4 weeks, in comparison of BIC, group T showed higher value with significant difference. Comparison of BA showed no significant difference among each implant. After 12 weeks, the highest mean BIC values were found in group T with significant difference. Group ZS showed higher BIC value with significant difference than group Z. In comparison of BA, group T and group ZS showed higher value with significant difference than group Z. Conclusion: Zirconia implant showed low levels of osseointegration in this experiment. Modification of surface structure should be taken into consideration in designing zirconia implants to improve the success rate.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.319-326
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• 2012

For many years, ceramics have been used in fixed prosthodontics for achieving optimal esthetics. but, they have another use as well. Many studies today show ceramics can be used for biomaterials. In the beginning researchers made a start in the study of aluminium oxide and sapphire for biomaterial. The appearance of Zirconia began a new phase of research. Zirconia was introduced into implantology as an alternative to titanium, because of its white color, good mechanical properties and superior biocompatibility. But it is not easy to surface treatment in comparison with titanium. To overcome the limitation, interconnected porous bodies of zirconia were fabricated by sintering technique. And the technique of coating was developed. Therefore, some zirconia implants are currently available. It is thought that Research of biomaterials as a variety of puposes for the use of zirconia is looking very promising. The purpose of this paper reviews are to evaluation of zirconia as biomaterials.

• The Journal of the Korean dental association
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• v.54 no.6
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• pp.404-413
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• 2016

Currently, dental implants have become predictable and reliable adjuncts for oral rehabilitation. Osseointegrated implants can be used to provide rigid orthodontic anchorage and have advantages compared conventional orthodontic anchorage especially when there were edentulous areas and implants were scheduled as a treatment plan. Orthodontic force doesn't cause the bone loss of osseointegrated implants. Implant materials, surgical protocols and healing time before loading follow the conventional treatment protocol. Because the implants, once installed, can't change the location, meticulous treatment planning should be preceded. Further investigations are needed to standardize the treatment protocol.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.214-221
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• 2011

Purpose: To date most of finite element analysis assumed the presence of 100% contact between bone and implant, which is inconsistent with clinical reality. In human retrieval study bone-implant contact (BIC) ratio ranged from 20 to 80%. The objective of this study was to explore the influence of bone-implant contact pattern on bone of the interface using nonlinear 3-dimensional finite element analysis. Materials and methods: A computer tomography-based finite element models with two types of implant (Mark III Br${\aa}$nemark$^{(R)}$, Inplant$^{(R)}$) which placed in the maxillary 2nd premolar area were constructed. Two different degrees of bone-implant contact ratio (40, 70%) each implant design were simulated. 5 finite element models were constructed each bone-implant contact ratio and implant design, and sum of models was 40. The position of bone-implant contact was determined according to random shuffle method. Elements of bone-implant contact in group W (wholly randomized osseointegration) was randomly selected in terms of total implant length including cortical and cancellous bone, while ones in group S (segmentally randomized osseointegration) was randomly selected each 0.75 mm vertically and horizontally. Results: Maximum von Mises strain between group W and group S was not significantly different regardless of bone-implant contact ratio and implant design (P=.939). Peak von Mises strain of 40% BIC was significantly lower than one of 70% BIC (P=.007). There was no significant difference between Mark III Br${\aa}$nemark$^{(R)}$ and Inplant$^{(R)}$ in 40% BIC, while average of peak von Mises strain for Inplant$^{(R)}$ was significantly lower ($4886{\pm}1034\;{\mu}m/m$) compared with MK III Br${\aa}$nemark$^{(R)}$ ($7134{\pm}1232\;{\mu}m/m$) in BIC 70% (P<.0001). Conclusion: Assuming bone-implant contact in finite element method, whether the contact elements in bone were wholly randomly or segmentally randomly selected using random shuffle method, both methods could be effective to be no significant difference regardless of sample size.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.28 no.2
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• pp.64-73
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• 2019

Various techniques have been developed, and the development of piezo electric devices have made it possible to widen the alveolar ridge even if the residual bone is dense or if there is a lack of cancellous bone between the cortical bones. In the operation of the mandibular posterior area, the flap is easily accessible to the ramus bone, from which high quality autogenous bone can be obtained, compared to other parts. A small autologous bone block can be used with particulated bone graft material using one screw for bone regeneration instead of a large autologous bone with two screws. The tapered implant design can minimize buccal bone fracture, even in severely atrophic mandibular areas. We report a case of 4 years following implant placement with ridge splitting and small autogenous bone graft in severly atrophic mandible. This report demonstrates a case of functional and aesthetic restoration in a patient through a collaboration.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.9-17
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• 2014

Purpose: The purpose of this study was to compare zirconia implants with titanium implants from the view point of biomechanical stability and histologic response on osseointegration when those were placed with xenograft materials. Materials and methods: Specimens were divided into two groups; the control group was experimented with eighteen titanium implants which had anodized surface and the experimental group was experimented with eighteen sandblasted zirconia (Y-TZP) implants. At the tibias of six pigs, implants were installed into bone defect sites prepared surgically and treated with resorbable membranes and bovine bone. Two pigs were sacrificed after 1, 4 and 12 weeks respectively. Each implant site was sampled and processed for histologic and histomorphometric analysis. The stability of implants was evaluated with a $Periotest^{(R)}$. And the interfaces between bone and the implant were observed with a scanning electron microscope. Results: In stability analysis there was no significant difference between Periotest values of the control group and the experimental group. In histologic analysis with a light microscope after 4 weeks, there was new bone formation with the resorption of bovine bone and the active synthesis of osteoblasts in both groups. In bone-implant contact percentage there was significant difference between both groups (P<.05). In bone area percentage there was no significant difference between both groups. In analysis of both groups with a scanning electron microscope there was a gap between bone and a surface at 4 weeks and it was filled up with bone formed newly at 12 weeks. Conclusion: When accompanied by xenograft using membrane, bone to implant contact percentage of zirconia implants used in this experiment was significantly less than that of the titanium implants by surface treatment of anodic oxidation. So, it is considered that the improvement of zirconia implant is needed through ongoing research on surface treatment methods for its practical use.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.313-321
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• 2016

Placenta accrete patients whose mother mortality rates are rather high due to massive bleeding during childbirth need to have Prophylactic placement of Internal Iliac Artery Balloon Occlusion Catheters procedure to reduce amount of blood loss and inoperative transfusion. Nevertheless, studies for mothers inevitably exposed to dose during PIIABOCs procedure have not been published many yet. Therefore, this study is to investigate exact information on radiation dose exposed to fetus during PIIABOCs procedure. Average effective dose of fetus per organ is 2.38~8.83 mGy, measured highest at beam center and followed by eyeball, stomach and bladder. The result showed that the longer fluoroscopy time is used, the closer beam center is and the thicker abdominal thickness is, the more effective dose on fetus is increasing. When using the collimator and protection shown to decrease the effective dose and when using higher the patient table shown to decrease the effective dose. It has been reported that the threshold of deterministic effect is about 100mGy. Deterministic effect was regarded as a factor that would influence on fetus exposed by medical radiation than stochastic effect. Consequently, it concluded that dose exposed on fetus in PIIABOCs procedure was approximately 10% of threshold of deterministic effect with effective dose of 0.49~18.27 mGy.