Assessment of dental implant stability in osseodistraction-generated bone: a resonance frequency analysis

Objective: To determine the implant stability in osseodistraction-generated (ODG) bone after a 2-month consolidation period, assessed by resonance frequency analysis (RFA).
Material and methods: Twenty healthy, non-smoker female patients received 71 dental implants, 39 placed in native bone and 32 in ODG bone, after an 8-week consolidation period. Primary and secondary stability of the implants was assessed by means of the Osstell^® mentor device. The average value of six measurements was considered for the statistical analysis at each time point.
Results: The age of the patients who received implants in ODG was not significantly different from that of those receiving implants in pristine bone (48.0±10.9); [ X =1.6; 95% confidence interval (CI)=−7.7–10.9].
Although implants placed in both bone types indicated good primary stability, a statistically significant difference in favour of implants placed in pristine bone could be identified in terms of osteogenic distraction (OD) ( X _i− X _j=3.4; 95% CI=1.7–5.8). After a 1.5-month integration period, none of the implants failed, but implant stability still recorded higher values for implants located in the pristine bone ( X _i− X _j=2.5; 95% CI=0.5–4.4).
A positive linear correlation could be established between the implant stability quotient (ISQ) values at implant placement (primary stability) and the post-integration ISQ score (secondary stability) for both bone types, but only 16% of the post-integration ISQ in the ODG bone could be attributed to the primary stability.
Conclusions: Within the limitations of this study, OD bone offers – after a 2-month consolidation period – high primary and secondary stabilities after implant placement.     

Resonance frequency analysis assessment of implant stability in labial onlay grafted posterior mandibles: a pilot clinical study

PURPOSE: The objectives of this study were (1) to compare the stability, evaluated by means of resonance frequency analysis (RFA), of implants placed posterior mandibles augmented with autogenous bone harvested from the mandibular symphysis with that of implants placed in nongrafted edentulous posterior mandibles and (2) to compare peri-implant marginal bone height changes and implant failure for the 2 groups. MATERIALS AND METHODS: Eight patients with thin posterior mandibular ridges (buccolingual crestal width less than 4 mm) underwent labial onlay alveolar grafting with symphyseal bone blocks 4 months prior to placement of 17 implants. Seven nongrafted patients received 18 implants in the edentulous posterior mandible; these patients served as a control group. RFA was performed the day of implant placement (baseline), 1 month postplacement, 4 months postplacement (after prosthesis delivery), and 12 months postloading. Peri-implant bone height changes at a level of 0.01 mm were assessed using periapical radiographs at baseline, the 1-month follow-up, and the 4-month follow-up. Analysis of variance was used to evaluate statistical differences within the groups, and t test was used to make comparisons between groups. RESULTS: None of the patients presented postoperative complications or implant failure. Mean implant stability quotient (ISQ) was 63.0+/-6.0 to 70.2 +/-3.5 for the grafted group and 64.1+/-4.1 ISQ to 70.1+/-3.9 for the nongrafted group. No significant difference was found in mean ISQ between the grafted and nongrafted groups at baseline, the 1-month follow-up, 4 months postplacement, or 12 months postloading (P = .211, P = .873, P = .925, P = .735, respectively). Mean peri-implant bone loss was 0.16 +/- 0.04 mm mesially and 0.16 +/- 0.05 mm distally. CONCLUSION: RFA revealed no difference in implant stability between mandibular ridges augmented with autologous bone grafts at baseline or after loading.     

Implant stability measurements using resonance frequency analysis in the grafted maxilla: a cross-sectional pilot study

Background: High failure rates have been presented for implants placed in grafted bone. The bone graft-implant interface constitutes a most complex healing situation, where the time scale for osseointegration and development of implant stability currently is not known. Purpose: The aim of the study was to measure the stability of implants placed in grafted bone after various follow-up periods. Methods: Implant stability measurements by means of resonance frequency analysis were performed in 10 patients previously treated with a Le Fort I osteotomy and interpositional bone grafts. The implants were placed 3 to 4 months after the grafting procedure. Sixty-seven Brånemark implants were subjected to resonance frequency analysis measurements at fixture placement and up to 5.5 years after implant surgery. Periapical radiographs were used for assessment of marginal bone levels. Results: The radiographic examinations showed marginal bone loss with time during the 5.5-year follow-up. The resonance frequencies varied from 5860 to 8440 Hz. When accounting for abutment length and marginal bone level, there was a tendency of increasing resonance frequency with time. Two implants with low resonance frequencies failed during the prosthetic phase. Conclusion: The results indicate an increased implant stability with time, which may reflect bone formation, remodeling, and maturation at the implant interface.     

Sensitivity of resonance frequency analysis method to assess implant stability

The aim of this human cadaver study was to determine the correlation between bone quality and implant stability parameters, and the relationship between resonance frequency value and peri-implant bone loss. Thirty-two implants were placed into four human cadaver mandibles. The bone density of the implant recipient site was determined using computerized tomography (CT) in Hounsfield units (HU). The peak insertion torque values were recorded. The resonance frequency (RF) measurements were performed immediately following implant insertion and also after one, two and three turns of the implant in a counterclockwise direction, representing peri-implant bone loss. The mean bone density, insertion torque and RFA values of all implants were 152 +/- 264 HU, 41.7 +/- 6 Ncm and 69.7 +/- 9 ISQ. Statistically significant correlations were found between bone density and insertion torque values, bone density and ISQ values, and insertion torque and ISQ values. A significant influence of the peri-implant bone loss on ISQ value was also observed. The findings from this study illustrate significant correlation between bone density and implant stability parameters, and a linear relationship between peri-implant bone levels and resonance frequency value.     

A comparison of implant stability quotients measured using magnetic resonance frequency analysis from two directions: a prospective clinical study during the initial healing period

Objectives: Given that the orientation of the transducer (mesiodistal or buccolingual) affects the data obtained from a piezoelectric resonance frequency analysis (RFA), this study evaluated whether it is necessary to use measurements taken in two different directions (mesiodistal and buccolingual) when using magnetic RFA to assess changes in the stiffness of dental implants. Materials and methods: A prospective clinical trial was completed, in a total of 53 patients, on 71 non‐submerged dental implants that were inserted to replace the unilateral loss of mandibular molars. All of the implants were of the same diameter (4.1 mm), length (10 mm), and collar height (2.8 mm). The implant stability quotient (ISQ) was measured during the surgical procedure, and at 4 and 10 weeks after surgery. Measurements were taken twice in each direction: in the buccolingual direction from the buccal side and in the mesiodistal direction from the mesial side. The average of two measurements in each direction was regarded as the representative ISQ of that direction. The higher and lower values of the two ISQs (buccolingual and mesiodistal) were also classified separately. In addition, the variation in ISQ was quantified by subtracting the lower value from the higher value, and the implants were classified into two groups according to this variation: one with ISQ variation of 3 or more and the other with a variation of <3. Results: There were no differences between the two ISQs when measured from different directions, but there were significant differences between the higher and lower values of the ISQs at each measurement point. A significant difference was also observed between the two ISQ variation groups in the pattern of change of the lower value for the period from immediately after surgery to 10 weeks after surgery. Conclusion: Acquisition of two directional measurements and classification of the higher and lower values of the two directional ISQs may allow clinicians to detect patterns of change in ISQ that would not be identified if only one directional measurement were made. To cite this article:
Park J‐C, Kim H‐D, Kim S‐M, Kim M‐J, Lee J‐H. A comparison of implant stability quotients measured using magnetic resonance frequency analysis from two directions: a prospective clinical study during the initial healing period.
Clin. Oral Impl. Res. 21 , 2010; 591–597.
doi: 10.1111/j.1600‐0501.2009.01868.x     

正畸微种植体稳定性的临床共振频率分析

目的 用共振频率分析法评价正畸微种植体稳定性的临床变化规律,探讨合适的加载时机及加载对微种植体稳定性的影响。方法 选择上颌第一前磨牙减数并需要强支抗的正畸患者14例,分为延期加载组和择期加载组各7例。每例患者在上颌后牙左右颊侧牙槽骨区植入分体式微种植体各1颗,用Osstell种植体稳定性测量仪作共振频率分析,植入后即刻及每周记录微种植体的种植体稳定性系数（implant stability quotients,ISQ值）。延期加载组在第12周加载150 g水平牵引力之前,选出ISQ值稳定的时间点,以此作为择期加载组的加载时机,施加同样大小的正畸力。2组患者均随访至16周,采用SPSS 19.0软件包对数据进行方差分析和t检验。结果 28颗微种植体中,5颗在4周内发生松动而取出,剩余23颗在16周内保持稳定,其中12颗延期加载组微种植体的共振频率分析显示,ISQ值在植入即刻及第1周最高（21.48±5.25）,第2周到第5周逐渐下降,第6周后维持平稳 （11.26±3.36）。11颗择期加载组微种植体在第6周加载牵引力。从第6周至16周,2组微种植体无论加载与否, ISQ 值均无显著变化,2组间也无显著差异（P>0.05）。松动微种植体的初始ISQ值显著小于非松动组。结论 微种植体植入1周后稳定性下降,6周后趋于稳定。6周后加载正畸力对稳定性无影响,而初始稳定性差是微种植体失败的重要原因。     

A newly designed resonance frequency analysis device for dental implant stability detection

Resonance frequency (RF) analysis technology was used to design a new dental implant stability detector. To calibrate and test the performance of this novel apparatus, in vitro and in vivo models, respectively, were used. The RF values of the test implants detected using our new device and a commercially available analogous device (Osstell) were compared. Further, implant stability status was also detected clinically using our device at 2, 4, 8, and 12 weeks after surgery. A high correlation was demonstrated between the values measured with the two devices (y = 0.31x-12.45; R2 = 0.98, p < 0.05). In our clinical tests, an initial RF value above 10.0 kHz indicated that the implant was ready to accept functional loading, while values in the 4.0-10.0 kHz range reflected the need for further osseointegration. In conclusion, these results indicated that our new device might be useful in a clinical setting for evaluating the healing status of a placed implant.     

Occlusal stability in implant prosthodontics -- clinical factors to consider before implant placement

The success of any prosthetic design depends on proper management of the occlusion. The clinical variables influencing occlusal stability must be determined and considered in the design of the final prosthesis. This paper outlines some of these variables.     

A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE

This study evaluated the initial stability of different implants placed above the bone level in different types of bone.

MATERIALS AND METHODS

As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Brånemark System® Mk III TiUnite™, Straumann Standard Implant SLA®, and Astra Tech Microthread™-OsseoSpeed™) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis.

RESULTS

In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Brånemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants.

CONCLUSION

The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.     

Clinical study on the primary stability of two dental implant systems with resonance frequency analysis

Primary stability has a major impact on the long-term success of dental implants. The aim of this study was to investigate the correlation of resonance frequency analysis (RFA) and insertion torque of self-tapping and non-self-tapping implants and their respective differences in primary stability. A group of 263 patients were treated with a total of 602 conically formed dental implants: 408 non-self-tapping Ankylos and 194 self-tapping Camlog. The maximum insertion torque during implant placement was recorded. Resonance frequency, measured as the implant stability quotient (ISQ), was assessed once immediately after insertion and twice 3 months later. Torque values of the non-self-tapping implants were significantly higher than those in the self-tapping group (p = 0.023). RFA did not show differences between the 2 groups (p = 0.956), but a correlation between ISQ values after implantation and 3 months after implant placement was measured (r = 0.712). Within the implant systems, no correlation between insertion torque and resonance frequency values could be determined (r = 0.305). Our study indicates that the ISQ values obtained from different implant systems are not comparable. The RFA does not appear suitable for the evaluation of implant stability when used as a single method. Higher insertion torque of the non-self-tapping implants appeared to confirm higher clinical primary stability.     

Measurement of mini-implant stability using resonance frequency analysis

Objective:To investigate whether resonance frequency analysis (RFA) is suitable to measure orthodontic mini-implant stability. Implant size significantly affects the level of resonance frequency. Regarding the operating mode of RFA, it has to be proven whether the resonance frequency of mini-implants in bone fits the range of frequency emitted by the Osstell ISQ device.Material and Methods:For this purpose the SmartPegs in the Osstell ISQ device were modified to fit with the inner screw thread of orthodontic mini-implants, and 110 mini-implants were inserted into porcine pelvic bone. RFA was performed parallel and perpendicular to the run of superficial bone fibers. A suitability test, Periotest, was also performed in the same directions. Compacta thickness was measured using cone-beam computed tomography. Correlation tests and linear regression analysis were carried out between the three methods.Results:The RFA showed a mean Implant Stability Quotient value of 36.36 ± 2.67, and the Periotest mean value was −2.10 ± 1.17. The differences between the two directions of measurement were statistically significant (P > .001) for RFA and the Periotest. There was a high correlation between RFA and the Periotest (r  =  −0.90) and between RFA and compacta thickness (r  =  0.71). The comparison between the Periotest and compacta thickness showed a correlation coefficient of r  =  −0.64.Conclusion:The present results suggest that RFA is feasible as a measurement method for orthodontic mini-implant stability. As a consequence, it could be used for clinical evaluation of current stability and allow stability-related loading of mini-implants to reduce the failure rate.     

Influence of factors related to implant stability detected by wireless resonance frequency analysis device

Summary Resonance frequency analysis (RFA) was introduced as a method for measuring implant stability more than a decade ago. Implant stability quotient (ISQ) values obtained using a recently introduced wireless RFA device have made it possible to evaluate stability in a non‐invasive technique; however, there are few studies of the factors that affect ISQ values determined using this device. The aim of the present study was to evaluate the association between ISQ values determined by wireless RFA and various factors related to dental implant stability using a pig cortical bone model. Dental implants (Replace^® Select Tapered implants) with a length of 10 mm were placed into pig cortical bone samples, then, ISQ values were determined using wireless RFA under various conditions (probe orientation, diameter of implant, insertion torque and peri‐implant bone loss). The results of this study showed that ISQ values were not affected by the direction of the probe from parallel to perpendicular to the long axis of the pig bone or to the smart peg. In addition, the diameter of the implant did not have a significant effect on the measured ISQ values. Statistically significant correlations were found between insertion torque and ISQ values (Spearman’s test, P < 0·05), and lower ISQ values were observed for deeper peri‐implant vertical defects (Mann–Whitney U‐test, P < 0·05). A wireless RFA device appears to be useful for measuring implant stability within the limits of the present in vitro study.     

Evaluation of two different resonance frequency devices to detect implant stability: a clinical trial

BACKGROUND: Resonance frequency analysis (RFA) provides a non-invasive assessment of implant stability. The established RFA device uses electronic technology, whereas a recently developed device uses magnetic technology. The goal of this clinical trial was to evaluate the ability of the magnetic RFA device to detect changes in stability during early healing following implant placement and to determine whether the implant stability quotient (ISQ) values obtained correlated with those made with the electronic device. METHODS: RFA assessments were performed using electronic- and magnetic-based devices on 34 non-submerged titanium dental implants in 17 patients. Each patient received two implants in the posterior maxilla or mandible. Implant stability was measured at placement and weekly until week 6, when implants received provisional crowns, and at 12 weeks, when definitive crowns were cemented. During each visit, measurements were taken three times and averaged to obtain a single representative ISQ for each device. RESULTS: At placement, the mean ISQ obtained with the electronic device was 61.9 (95% confidence interval [CI], 59.4 to 64.3); it increased to 63.2 (95% CI, 61.2 to 65.2) at 12 weeks. With the magnetic device, the mean ISQs were 70.6 (95% CI, 68.4 to 72.8) and 75.9 (95% CI, 74.2 to 77.7), respectively. Both devices indicated a pattern of decreased mean stability from 1 to 3 weeks post-placement, small fluctuations in mean ISQ from 3 to 6 weeks, and significantly increased mean stability from 6 to 12 weeks. For the complete set of implant measures across all weeks, the paired electronic and magnetic ISQ values correlated significantly (r = 0.52; P <0.001). CONCLUSIONS: This study demonstrates that changes in implant stability measured with the newer magnetic device correlate well with those found with the electronic device. Both devices confirmed the initial decreases in implant stability that occur following placement and identified an increase in stability during the first 6 weeks of functional loading.     

单个种植体即刻种植即刻负重骨结合情况的动物实验研究

目的本实验设计了单个种植体即刻种植即刻负重的动物模型,目的在于研究种植体周围硬组织的变化.方法选取8只成年狗,体重10～15 kg.分别拔除每只狗的双侧下颌第二前磨牙;同时,各植入一枚ITI种植体,分别以20Ncm及30Ncm的扭矩旋入.实验侧即刻以树脂冠行上部结构修复,对照侧无负荷.每只狗在植入种植体后和处死后拍X线片,观察其影像学的改变.动物分别于1个月和3个月处死后取标本,观察其组织学的改变.结果16枚种植体中14枚种植体获得良好的骨结合,种植体周围包绕着致密的骨组织,未观察到任何间隙和结缔组织长入.实验侧1枚种植体脱落,对照侧1枚种植体松动.结论单个种植体的即刻种植即刻负重是一个可行的选择.     

Early detection of implant healing process using resonance frequency analysis

In this study, in vitro and in vivo models were adopted for assessing the application of resonance frequency analysis (RFA) in the early detection of implant stability. In the in vitro tests, RF values of implants placed in bone block with predrilled cavities of 3.75 and 5.0 mm were measured and compared. Stone was used to fill the inter-space between implants and the bone blocks. Our results showed that poor initial stability conditions contributed to a lower initial RF (IRF) value (5.41+/-0.32 kHz) and a longer simulated healing period (41 min) than that of well-fitted conditions (9.63+/-0.34 kHz for IRF, 14 min for the simulated healing period, P<0.05). To validate such in vitro tests, animal models were also performed. Implants were placed in the left tibias of six rabbits using a general surgery procedure. The modal testing method was used to test the RF values of the implants. The RF values of the implants increased significantly (P<0.05) during the healing period and reached a plateau when the implant-bone interface was united. The variations of RF values of the testing implants showed a similar trend to the results of in vitro tests, i.e., implants with higher initial RF values had shorter simulated healing times. Based on these findings, we concluded that RFA is a reliable and accurate method for early assessment of the osseointegration process.     

不同骨移植材料用于种植同期GBR术式的临床比较

目的：比较不同骨移植材料在种植同期行膜引导骨冉生（GBR）手术式的临床效果。方法：69例单牙缺失的种植修复病例,根据骨移楠材料的不同分为3组：A组采用人工骨;B组采用人工骨与自体骨混合;C组为自体骨。常规完成种植删期GBR手术式,6个月后再次翻瓣,比较其骨移植临床效果。结果：A组20例中有5例发生移植骨未格合机体暴露,B组25例中有2例发生移植骨未整合植体暴露,C组24例中有3例发生移植骨术整介植体暴露。经统计学分析,三组骨移植临床效果差异无统计学意义。结论：临床观察,三种骨移植材料GBR于术式短期内骨移植临床效果无明显差异。