• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.487-495
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• 2004

In order to compare the induced time of osteoporosis between ovariectomized and neurectomized models in ddY mice. Experimental groups were divided into Sham, ovariectomized (OVX group) and neurectomized (NX group) group. The changes of body weight, tibia weight and histomorphometry of epiphyseal regions of tibia that were generally used as criteria index in osteoporosis, were evaluated at 2 and 4 weeks after operations with other generally used index-changes of serum osteocalcin. Also, calcium and phosphorus levels in the ash tibia were demonstrated with their ratio (Ca/P ratio). From the result of this study, evidences which reflect osteoporotic states of animals such as decrease of absolute and relative tibia weight, histomorphometrical index of epiphyseal region of tibia including trabecular bone volume %, and calcium and phosphorous contents in tibia, were generally detected from 4 weeks after ovariectomy and 2 weeks after neurectomy with increase of serum osteocalcin levels. In conclusion, it is considered that more rapid and favorable osteoporosis was induced in neurectomized model compared to that of ovariectomized model.

• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.465-478
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• 2007

Various periodontal barrier membranes used in many clinical and experimental fields, and many recent studies of membranes have reported good results. To improve clinical results, selection of barrier membranes is an important factor. So, we need not only to evaluate various barrier mem-branes, but also to understand the property of barrier membranes appropriate to defect characteristics. For this purpose, this study reviewed available literature, evaluated comparable experimental models, and compared various barrier membranes. From above mentioned methods, the following conclusions are deduced. 1. In i-wall periodontal defect models, new bone formation showed a consistent result, almost 30% of the defect size. New cementum formations measured mostly 40% of the defect size, but showed more variations than new bone formations. This seems to be resulted form difference in experimental methods, so standardization in experimental methods is needed for future studies. 2. Application PLGA barrier membrane to periodontal defect demonstrated improved healing in new bone and new cementum. 3. There was a minimal periodontal regeneration with calcium sulfate barrier membrane only. But, there was better healing pattern in combination of calcium sulfate membrane with bone graft material, such as DFDBA, 4. There was no significant difference between the experimental group that used chitosan mem-brane only and the control group. But, in combination with bone graft material for space maintanence, periodontal regeneration was improved. Overall, Space maintenance is a critical factor for Guided tissue regeneration using barrier membranes. Also, a barrier membrane itself that has difficulty in maintaining space, achieved better result when used with graft material.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.243-248
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• 2009

Purpose: Rehabilitation of the edentulous posterior maxilla with dental implants often poses difficulty because of insufficient bone volume caused by pneumatization of the maxillary sinus and by crestal bone resorption. Sinus grafting technique was developed to increase the vertical height to overcome this problem. The present study was designed to evaluate the sinus floor augmentation with anorganic bovine bone (Bio-$cera^{TM}$) using histomorphometric and clinical measures. Patients and methods: Thirteen patients were involved in this study and underwent total 14 sinus lift procedures. Residual bone height was ${\geq}2mm$ and ${\leq}6mm$. Lateral window approach was used, with grafting using Bio-$cera^{TM}$ only(n=1) or mixed with autogenous bone from ramus and/or maxillary tuberosity(n=13). After 6 months of healing, implant sites were created with 3mm diameter trephine and biopsies taken for histomorphometric analysis. The parameters assessed were area fraction of new bone, graft material and connective tissue. Immediate and 6 months after grafting surgery, and 6 months after implantation, computed tomography (CT) was taken and the sinus graft was evaluated morphometric analysis. After implant installation at the grafted area, the clinical outcome was checked. Results: Histomorphometry was done in ten patients.Bio-$cera^{TM}$ particles were surrounded by newly formed bone. The graft particles and newly formed bone were surrounded by connective tissue including small capillaries in some fields. Imaging processing revealed $24.86{\pm}7.59%$ of new bone, $38.20{\pm}13.19%$ connective tissue, and $36.92{\pm}14.51%$ of remaining Bio-$cera^{TM}$ particles. All grafted sites received an implant, and in all cases sufficient bone height was achieved to install implants. The increase in ridge height was about $15.9{\pm}1.8mm$ immediately after operation (from 13mm to 19mm). After 6 months operation, ridge height was reduced about $11.5{\pm}13.5%$. After implant installation, average marginal bone loss after 6 months was $0.3{\pm}0.15mm$. Conclusion: Bio-$cera^{TM}$ showed new bone formation similar with Bio-$Oss^{(R)}$ histomorphometrically and appeared to be an effective bone substitute in maxillary sinus augmentation procedure with the residual bone height from 2 to 6mm.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.403-414
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• 2002

I. Purpose of Study Zea Mays L. has been known to be effective for improving periodontal health and Magnoliae cortex to have effective antibacterial and antimicrobial activity against periodontal pathogens. The purpose of this study was to examine the biologic effects of Zea Mays L. and Magnoliae cortex extract mixtures on healing of rat calvarial bone defects. II. Materials & Methods 8mm circular defects were prepared on rat calvaria during surgical procedures of 180 Sprague-Dawley rats. The ethanolic extracts of Magnoliae cortex and Zea Mays L. and these two natural extract 1:1 and 2:1 (Magnoliae: Zea Mays L.) ratio mixtures were oral administrated by oral zondes once a day at two different dose of 94.5mg/kg, 189mg/kg body weight. There are nine groups of rats in this study: control group (no sample loading), Magnoliae cortex extract loading groups (I,II)(94.5mg/kg,189mg/kg respectively), Zea Mays L. extract loading groups (I,II), M:Z(1:1) loading groups (I,II), M:Z(2:1) loading groups(I,II). Rats were sacrificed at 4 weeks and 6 weeks after surgery. New bone formations around calvarial defects were radiographically and histologically measured by computerassisted histomorphometry. Each data was statistically analyzed by One-way ANOVA test. III. Results There were statistical significances between negative control group and the other test groups on radiographical and histological quantitative assessments. Among test groups, mixture groups showed statistical significances, especially, M:Z (2:1) groups (I and II) were highly significant.(p<0.05) These results implicated that the mixture of Magnoliae and Zea Mays L. (2:1 mixing ratio) with 94.5mg/kg concentration might be highly effective on the wound healing of bony defected site and have potential possibilities as a useful drug to promote bone tissue regeneration.

• Journal of Periodontal and Implant Science
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• v.51 no.4
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• pp.264-275
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• 2021

Purpose: Periodontitis is considered a local risk factor for medication-related osteonecrosis of the jaws (MRONJ). However, little is known about the progression of periodontitis in the presence of zoledronic acid (ZOL). The aim of this study was to evaluate the effects of the systemic use of ZOL on the progression of experimental periodontitis (EP) in rats, as ZOL could modulate the progression of periodontitis and concomitantly cause MRONJ in individuals with periodontitis. Methods: Forty-eight male Wistar rats were randomly distributed in 6 groups (n=8 each). To induce EP, ligatures were placed around the right first mandibular molars. Three groups were treated with ZOL (0.15 mg/kg/week, intraperitoneal), and 3 with 0.9% saline solution (controls). In the ZOL/Lig30 and ZOL/Lig 15 groups, after 4 weeks of treatment with ZOL, EP was induced and euthanasia was performed after 30 and 15 days of EP induction, respectively. In both groups, the animals continued to receive ZOL after EP until the end of the experiment. In the Lig/ZOL group, EP was induced first, and 15 days later, ZOL was administered for 8 weeks, with euthanasia 1 week after the last dose. After euthanasia, the mandibles were evaluated using micro-computed microtomography (micro-CT) and histomorphometry. Bone loss was measured, and the presence of osteonecrosis was evaluated histologically. The data were evaluated using the Student t-test and the Mann-Whitney test, with a significance level of 5%. Results: In the Lig/ZOL group, micro-CT revealed less alveolar bone resorption in the distal root (P<0.01) than in the control group (Lig/Con). Histomorphometric analysis confirmed less alveolar bone resorption in the Lig/ZOL group (P=0.001). Histologically, osteonecrosis was more common in the ZOL groups. Conclusion: ZOL decreased alveolar bone resorption in rats with EP. However, it presented a higher risk for MRONJ.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.136-142
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• 2009

Bone density in the recipient implant site seems to be an important factor for long term success of endosseous implants. Preoperative evaluation of bone density is very helpful to assist the clinician with the treatment planning of implant therapy. Accurate information on bone density will help the surgeon identify suitable implant sites, thereby improving the success rate of the procedure. Purpose; The aim of this study was to evaluate a correlation between bone density measured preoperatively with computerized tomography and histologically measured bone density by bone biopsy. Patients and methods; Twenty seven patients were selected. All the patients were in good health, with no systemic disorder and additional bone graft. Preoperatively the patients underwent CT scanning to evaluate Houmsfield Unit(HU). Each patients wore a surgical template for implant placement. During surgery 2mm in diameter and 6mm in length specimens were taken. Histomorphometric analysis was performed using digitalized image analysis software Axiovision 4.3. Also, the Resonance frequency analysis(RFA) and insertion torque values were recorded. Results; The highest histomorphometric values was found in the posterior mandible $32.3{\pm}3.8$, followed by $29.9{\pm}2.6$ for the posterior maxilla, $29.4{\pm}2.6$ for the anterior maxilla, $28.6{\pm}2.3$ for the anterior mandible(p=0.214). The hounsfield unit was $989.2{\pm}258.1$ in the posterior mandible, $845.0{\pm}241.5$ in the anterior maxilla, $744.5{\pm}92.6$ in the anterior mandible, $697.3{\pm}136.9$ in the posterior maxilla(p=0.045). This results may suggest that there are strong correlation between the histomorphometric values and hounsfield unit(r=0.760, p<0.05). The RF measurements were $81.9{\pm}2.4$ ISQ in the posterior mandible, $79.0{\pm}1.4$ ISQ in the anterior mandible, $78.3{\pm}4.6$ ISQ in the posterior maxilla, $76.5{\pm}5.0$ ISQ in the anterior maxilla(p=0.048). The insertion torque values was $43.2{\pm}4.2\;Ncm$ in the posterior mandible, $42.0{\pm}0.0\;Ncm$ in the anterior mandible, $41.3{\pm}4.1\;Ncm$ in the posterior maxilla, $40.8{\pm}3.8\;Ncm$ in the anterior maxilla(p=0.612). This results may suggest that there are statistical significance between the hounsfield unit and the insertion torque values(r=0.494, p<0.05), the histomorphometric values and the insertion torque values(r=0.689, p<0.05). But there was no correlation between histomorphometric values and ISQ. There was no statistical significance in age and gender effect on parameters. Conclusions; There was significant correlations between bone density and implant stability parameters. The bone density measurements using preoperative CT may help clinicians to predict primary stability before implant insertion, which is associated with implant survival rates.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.7-14
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• 2008

Purpose: Chitosan & chitosan derivative(eg. membrane) have been studied in periodontal regeneration, and recently many studies of chitosan have reported good results. If chitosan's effects on periodontal regeneration are enhanced, we can use chitosan in many clinical and experimental fields. For this purpose, this study reviewed available literatures, evaluated comparable experimental models. Materials and Methods: Ten in vivo studies reporting chitosan's effects on periodontal tissue regeneration have been selected by use of the 'Pubmed' and hand searching. Results: 1. In Sprague Dawley rat calvarial defect models, amount of newly formed bone in defects showed significant differences between chitosan/chitosan-carrier/chitosan-membrane groups and control groups. 2. In beagle canine 1-wall intrabony defect models, amount of new cementum and new bone showed significant differences between chitosan/chitosan-membrane groups and control groups. The mean values of the above experimental groups were greater than the control groups. Conclusion: The results of this study have demonstrated that periodontal regeneration procedure using chitosan have beneficial effects, which will be substitute for various periodontal regenerative treatment area. One step forward in manufacturing process of chitosan membrane and in use in combination with other effective materials(eg. bone graft material or carrier) may bring us many chances of common use of chitosan in various periodontal area.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.337-349
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• 2008

Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in delayed loading conditions. A total of 36 solid screw implants (diameter 3.75 mm, length 10mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium Implants served as control. Gold crowns were inserted 3 months. Radiographic assessments and stabilitytests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 1 and 3 months after loading. Histological observations and morphometrical measurements were also performed. Of 36 implants, 32 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (p=0.413) and RFA values. The mean BIC % in the Mg-implants was $54.4{\pm}20.2%$. The mean BIC % in the turned implant was $48.9{\pm}8.0%$. These differences between the Mg-implant and control implant were not statistically significant (P=0.264). In the limitation of this study, bone-to-implant contact (BIC) and bone area of Mg-incorporated oxidized implant were similar to machine-turned implant. The stability analysis showed no significantly different ISQ values and marginal bone loss between two groups. Considering time-dependent bone responses of Mg-implant, it seems that Mg-implants enhanced bone responses in early loading conditions and osseointegrated similarly to cp Ti implants in delayed loading conditions. However, further investigations are necessary to obtain long-term bone response of the Mg-implant in human.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.122-127
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• 2010

Purpose: The objective of this study was to investigate the effects of calcium phosphate coated titanium implant surface on bone response and implant stability at early stage of healing period of 3 weeks and later healing period of 6 weeks. Material and methods: A total of 24 machined, screw-shaped implants (Dentium Co., Ltd., Seoul, Korea) which dimensions were 3.3 mm in diameter and 5.0 mm in length, were used in this research. All implants (n = 24), made of commercially pure (grade IV) titanium, were divided into 2 groups. Twelve implants (n = 12) were machined without any surface modification (control). The test implants (n = 12) were anodized and coated with thin film (150nm) of calcium phosphate by electron-beam deposition. The implants were placed on the proximal surface of the rabbit tibiae. The bone to implant contact (BIC) ratios was evaluated after 3 and 6 weeks of implant insertion. Results: The BIC percentage of calcium phosphate coated implants ($70.8{\pm}18.9%$) was significantly higher than that of machined implants ($44.1{\pm}16.5%$) 3 weeks after implant insertion (P = 0.0264). However, there was no significant difference between the groups after 6 weeks of healing (P > .05). Conclusion: The histomorphometric evaluation of implant surface revealed that; 1. After 3 weeks early healing period, bone to implant contact (BIC) percentage of calcium phosphate coated implants (70.8%) was much greater than that of surface untreated machined implants (44.1%) with P = 0.0264. 2. After 6 weeks healing period, however, BIC percentage of calcium phosphate coated implants group (79.0%) was similar to the machined only implant group (78.6%). There was no statistical difference between two groups (P = 0.8074). 3. We found the significant deference between the control group and experimental group during the early healing period of 3 weeks. But no statistical difference was found between two groups during the later of 6 weeks.