• The korean journal of orthodontics
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• v.40 no.3
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• pp.167-175
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• 2010

Objective: The aim of this study was to validate the Periotest values for the prediction of orthodontic mini-implants' stability. Methods: Sixty orthodontic mini-implants (7.0 mm $\times$ $\emptyset1.45$ mm; ACR, Biomaterials Korea, Seoul, Korea) were inserted into the buccal alveolar bone of 5 twelve month-old beagle dogs. Insertion torque (IT) and Periotest values (PTV) were measured at the installation procedure, and removal torque (RT) and PTV were recorded after 12 weeks of orthodontic loading. To correlate PTV with variables, the cortical bone thickness (mm) and bone mineral density (BMD) within the cortical bone and total bone area were calculated with the help of CT scanning. Results: The BMD and cortical bone thickness in mandibular alveolus were significantly higher than those of the maxilla (p < 0.05). The PTV values ranged from -3.2 to 4.8 for 12 weeks of loading showing clinically stable mini-implants. PTV at insertion was significantly correlated with IT (-0.51), bone density (-0.48), cortical bone thickness (-0.42) (p < 0.05) in the mandible, but showed no correlation in the maxilla. PTV before removal was significantly correlated with RT (-0.66) (p < 0.01) in the mandible. Conclusions: These results show that the periotest is a useful method for the evaluation of mini-implant stability, but it can only be applied to limited areas with thick cortical and high density bone such as the mandible.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.278-286
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• 2018

Purpose: The purpose of this study was to evaluate the effect of healing abutment height and measurement angle on implant stability when using Periotest and AnyCheck. Materials and methods: 60 implants were placed into artificial bone blocks. After implant insertion, 2, 3, 4 and 5 mm healing abutments were installed on 15 specimens, respectively. Insertion torque value, implant stability test, Periotest value were measured. Insertion torque value was controlled between 45 - 55 Ncm. AnyCheck was used for measuring implant stability test and Periotest M was used for measuring Periotest value. Implant stability test and Periotest value were measured at the angles of 0 and 30 degrees to the horizontal plane. Measured values were analyzed statistically. Results: Insertion torque value had no significant difference among groups. When healing abutment height was higher, implant stability test and Periotest value showed lower stability. Also when measurement angle was decreased, implant stability test and Periotest value showed lower stability. Conclusion: When measuring stability of implants with percussion type devices, measured values should be evaluated considering height of healing abutments and measurement angle.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.209-216
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• 2008

Statement of problem: It is difficult about assessing the loosening tendency of conical connection type implant after cyclic loading with diamond like carbon coating one-piece abutments, and also about the retightening effect. Purpose: This study was performed to investigate the influence of one-piece abutment screw retightening after $5.0{\times}10^{4}$ cyclic loading and Diamond like coating Material and methods: Thirty two ITI implant were divided to 4 groups. Group 1,3-titanium abutment, group 2,4 - diamond like carbon coated abutment. Group 1,2 - $20.0{\times}10^{4}$ cyclic loading after $5.0{\times}10^{4}$ cyclic loading, Group 3,4- after $20.0{\times}10^{4}$ Cyclic loading. After cyclic loading, periotest values were taken and removal torque values of abutments were measured with a digital torque gauge. Results: 1. The removal torque of group 2 after $5.0{\times}10^{4}$ cyclic loading is slightly greater than the other groups but not significantly higher than others (P>0.05). 2. The final removal torque values after $20.0{\times}10^{4}$ cyclic loading of group 1 is bigger than group 3, and group 2 is bigger than group 4, but not significantly higher (P>0.05). 3. The final removal torque values after $20.0{\times}10^{4}$ cyclic loading of all groups are not significantly different (P>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.128-137
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• 2011

Purpose: Resonance frequency analysis, Periotest, and removal torque (RT) test were known as the methods to assess implant stability. The results of these methods are affected by the bone condition, implant diameter and shape. The purpose of this study is to access the meaning and the correlationship of the resonance frequency analysis, Periotest and RT test in osseointegration simulated acrylic resin when the engaged bone thickness and peri-implant bone defect are changed. Materials and methods: To simulate osseointegration, the fixture was fixed to an aluminum mold with a screw. Acrylic resin powder and liquid were poured into the mold for polymerization. The engaged resin thickness with implant was controlled. Simulated cortical bone thicknesses were 1, 3, 5 and 10 mm. Additional 1, 3 and 5 mm peri-implant bone defects were simulated. Three types of implants were used; 4 mm diameter implants of straight shape, 4 mm diameter implants of tapered shape and 5 mm diameter implants of tapered shape. Five fixtures per each type were tested in respective bone condition. Resonance frequency analysis and Periotest were evaluated in all bone conditions. Peak removal torque was measured at simulated cortical bone thicknesses of 1 and 3 mm. The statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, and Spearman test using a 95% level of confidence. Results: With increasing engaged bone depth, the Implant Stability Quotient (ISQ) values increased and the Periotest values (PTVs) decreased (P<.001, P<.001). With increasing peri-implant bone defect, ISQ values decreased and PTVs increased (P<.001). When the diameter of implant increased, ISQ values increased and Periotest values (PTV) decreased (P<.001). There was a strong correlation between ISQ values and PTVs (r = -0.99, P<.001). Furthermore, the peak removal torque values had weak correlations with both ISQ values and PTVs (r = 0.52, P<.001 ; r = -0.52, P<.001). Conclusion: This study confirmed favorable implant stability with increasing engaged bone depth and implant diameter and decreasing peri-implant bone defect. ISQ values and PTVs showed strong correlation with each other and not with the peak removal torque values.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.300-307
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• 2011

Purpose: This study evaluated PostGraft$^{TM}$ which enhances implant stability and bone density. Materials and methods: Forty eight implants were installed at the tibia of ovariectomized rats. The group administrated with PostGraft$^{TM}$ was the experimental group, and the control group was not administrated. Implant stability was evaluated at the $2^{nd}$, $4^{th}$ and $6^{th}$ week by Periotest value, bone mineral density, bone-to-implant contact. These values were analyzed statistically with Mann-Whitney U test (P<.05). Histological analysis was evaluated at the $2^{nd}$, $4^{th}$ and $6^{th}$ week. Results: According to the Periotest$^{(R)}$ measurement, both experimental and control groups showed decrease in values as time elapsed. Greater decrease was observed in the experimental group but there was no significant difference. By examining the radiographic images, both experimental and control groups showed tendency of increase in bone density. Greater increase was seen in the experimental group but there was no significant difference. According to the bone-to-implant contact measurement, both experimental and control groups showed increase in values as time elapsed. Greater increase was seen in the experimental group. At the $2^{nd}$ and $4^{th}$ week, there was no significant difference. But at the $6^{th}$ week, there was significant difference (P<.05). By histological analysis, both experimental and control groups showed increase in bone formation as time elapsed. In addition, greater increase was seen in the experimental group. Conclusion: It could be concluded that the PostGraft$^{TM}$ medicated group showed better results in the bone density and osseointegration.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.128-134
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• 2010

Purpose: The aim of this study was to evaluate the changes in bone density and reduction of time consumed for osteogenesis by $PostPlant^{TM}$ Calcium and to find out efficacy of $PostPlant^{TM}$ Calcium by comparing the group prescribed with $PostPlant^{TM}$ Calcium with the group without $PostPlant^{TM}$ Calcium prescription. Material and methods: The experimental group of 18 patients with 25 dental implant placement and the control group of 7 patients with 9 dental implant placement were randomly selected from the patients who visited prosthetic department of Dankook University Dental Hospital since July, 2006 (IRB Number ; 20060710). The experimental group was instructed to take $PostPlant^{TM}$ Calcium for 6 months after the implant surgery while the control group was instructed not to. Both experimental and control group were assigned for measurement using $Osstell^{TM}$ Mentor and $Periotest^{(R)}$ and radiographic examination was performed using specifically manufactured Aluminum Step Wedge. The results were compared and analyzed. Results: 1. According to the $Osstell^{TM}$ Mentor measurement, both the experimental and control group showed increase in values as time elapses and the experimental group showed significantly higher rate of increase (P < .05). 2. According to the $Periotest^{(R)}$ measurement, both the experimental and control group showed decrease in values as time elapses. In addition, greater decrease can be seen in the experimental group but no statistical significance was found. 3. By examining the radiographic images, both the experimental and control group showed tendency of increase in bone density. In addition, greater increase can be seen in the experimental group but no statistical significance was found. Conclusion: Clinically, taking $PostPlant^{TM}$ Calcium medicine for a long period of time after implant placement is expected for a better prognosis.

• 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.34 no.3
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• pp.167-174
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• 2018

Purpose: The purpose of present study was to retrospectively analyze the survival rate of implant placed after alveolar ridge preservation by initial stability and radiographic measurements. Materials and Methods: In total, 19 patients who received 21 sandblasted, large-grit, acid-etched (SLA) implants were enrolled in this retrospective study. Implants placed after alveolar ridge preservation technique (ARP) 2 - 3 months healing period, Periotest value (PTV) measured at implant placement and before placed prosthodontics. Marginal bone level (MBL) was measured at implant placement and final recall check. Results: Overall survival rate of implant was 100%. Mean PTV at implant placement was $-0.06{\pm}8.33$ and mean PTV before placed prosthodontics was $-5.75{\pm}1.7$. The range of MBL change was from -0.55 mm to 1.6 mm (Mean: $0.19{\pm}0.58mm$). Conclusion: The findings of present study suggest that the implant paced after alveolar ridge preservation appear high survival rates and stable MBL.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.490-499
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• 2008

Statement of problem: Bioactive materials must have the ability to spontaneously form a bone like apatite layer on their surface and induce direct biochemical bonding to bone. A simple chemical treatment via alkali and heat has been revealed to induce bioactivity in titanium. Purpose: The purpose of this study was to evaluate the surface characteristics and stability of alkali and heat treated implants. Material and methods: Specimens were divided into three groups; group 1 was the control group with machined surface implants, groups 2 and 3 were treated with alkali solutions and heat treated in the atmosphere and vacuum conditions respectively. The surface characteristics were observed with FESEM, XPS, TF-XRD and AFM. Stability was evaluated with the resonance frequency analysis, periotest and removal torque values. One-way ANOVA and Duncan test were used for statistical analysis. Results: 1. Groups treated with alkali and heat showed similar characteristics. Groups 2 and 3 showed high compositions of Na ions on the surface with sub-micron sized pores compared to group 1. Group 2 showed mixed compositions of anatase and rutile with superior contents of rutile. 2. Resonance frequency analysis : The ISQ of group 2 showed significantly higher values than that of groups 1 and 3 at 12 weeks. The ISQ of groups 1 and 2 showed significant increase after 4 weeks, and the ISQ of group 3 increased significantly after 2 and 4 weeks respectively (P < .05). 3. Periotest: The PTV of groups 1 and 2 showed significant decrease after 4 weeks, and the PTV of group 3 showed significant decrease after 2 and 4 weeks respectively (P < .05). 4. Removal torque analysis: The removal torque value of group 2 was significantly higher than those of groups 1 and 3 at 2, 4 and 8 weeks. The removal torque values of groups 1 and 3 showed increase at 4 and 12 weeks, but the removal torque value of group 2 showed increase after 4 weeks (P < .05). Conclusion: An oxide layer with appropriate crystal structure and amorphous sodium titanate layer can be obtained on titanium implants through alkali and heat treatment in the atmosphere, and even alkali and heat treatment in vacuum conditions, provided a bioactive surface containing sodium. These surface layers can be considered to be effective for enhancement of osseointegration and reduction of healing period for implant treatment.