| Abstract|| |
Initial stability at the placement and development of osseointegration are two major issues for implant survival. Implant stability is a mechanical phenomenon which is related to the local bone quality and quantity, type of implant, and placement technique used. The application of a simple, clinically applicable, non-invasive test to assess implant stability and osseointegration is considered highly desirable. Resonance frequency analysis (RFA) is one of such techniques which is most frequently used now days. The aim of this paper was to review and analyze critically the current available literature in the field of RFA, and to also discuss based on scientific evidence, the prognostic value of RFA to detect implants at risk of failure. A search was made using the PubMed database to find all the literature published on "Resonance frequency analysis for implant stability" till date. Articles discussed in vivo or in vitro studies comparing RFA with other methods of implant stability measurement and articles discussing its reliability were thoroughly reviewed and discussed. A limited number of clinical reports were found. Various studies have demonstrated the feasibility and predictability of the technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are based on short-term results and long-term follow up are still scarce in this field. Nonetheless, from available literature, it may be concluded that RFA technique evaluates implant stability as a function of stiffness of the implant bone interface and is influenced by factors such as bone type, exposed implant height above the alveolar crest. Resonance frequency analysis could serve as a non-invasive diagnostic tool for detecting the implant stability of dental implants during the healing stages and in subsequent routine follow up care after treatment. Future studies, preferably randomized, prospective longitudinal studies are certainly needed to establish threshold ranges for implant stability and for implants at risk for losing stability for different implant system.
Keywords: Implant stability, resonance frequency analysis (RFA), implant stability quotient, Osstell
|How to cite this article:|
Gupta RK, Padmanabhan TV. Resonance frequency analysis. Indian J Dent Res 2011;22:567-73
Dental implants have been widely used to retain and support cross-arched fixed partial dentures. ,,,,,, It has been advocated that after implant placement, surgical sites should be undisturbed for at least 3-6 months to allow uneventful wound healing, thereby enhancing osseointegration between the implant and bone.  The rationale behind this approach is that implant micromovement caused by functional force around the bone-implant interface during wound healing may induce fibrous tissue formation rather than the bone contact, leading to clinical failure.  In addition, coverage of an implant has also been thought to prevent infection and epithelial down growth. , However, this discomfort, inconvenience, and anxiety associated with waiting period remains a challenge to both patients and clinicians. Hence, loading implants right after placement was attempted and has gained popularity among clinicians.  Current trends and demands have revealed the need for faster restoration of dental function using implants, which lead to the introduction of early and immediate loading protocols.
One of the major causes for implant failure is lack of primary stability, i.e., the stability of the implant at the time of implant placement. Primary implant stability is a prerequisite for successful osseointegration, and that implant instability results in fibrous encapsulation. , Achievement and maintenance of implant stability are prerequisite for long-term positive outcomes for osseointegrated implants. Thus, implant stability is the key to clinical success.  Thus, the success of immediate or early loading implant techniques is dependent on the ability of the clinicians to determine the degree of primary implant stability and changes in the stability along with new bone formation and remodeling.  Continuous monitoring in an objective and quantitative manner is important to determine the status of implant stability.  So, there is a clear and demonstrable need for a rapid, user friendly, non-invasive technique to clinically assess implant stability and osseointegration.
Primitive methods such as percussion and mobility testing by application of lateral forces with mirror handles have been used to determine primary stability. More recent methods have involved measuring cutting torque resistance and insertion torque values, both of which lack repeatability. Reverse torque test are invasive and destructive, hence impractical in a clinical setting. , Other techniques such as the Periotest and dental fine tester were primarily developed for use on natural teeth and are subjected to several variables, and hence questionable for accuracy and reliability. Histomorphometric and histologic analysis of the bone implant interface, while reliable, is not practical in a clinical setting.  The need for a user friendly, non-invasive, reliable, and clinically applicable technique to measure implant stability lead to the development of resonance frequency analysis (RFA) by Meredith and co-workers in 1996.  A commercially available electronic device, based on RFA, with the trade name OSSTELL, is used widely for clinical and experimental purposes.
Therefore, the purpose of this paper is to review and analyze critically the current available literature in the field of RFA and also to discuss based on scientific evidence, the prognostic value of this system to detect implants at risk of failure.
| Search Strategy|| |
A Medline search was performed to find all of the available literature on "Resonance frequency analysis for implant stability" till date. Search revealed that high-level evidence publications and long-term clinical trials were virtually absent.
Although there were numerous articles available on RFA (n=141), articles discussed in vivo or in vitro studies comparing RFA with other methods of measuring implant stability and articles discussing reliability of RFA were included for review (n=49). Consequently, a review was prepared to cover the working principle, reliability, clinical relevance, and effectiveness of RFA.
| Resonance Frequency Analysis|| |
Basic vibrational theory was applied to design a transducer that could be excited using a steady state, swept frequency waveform and its response measured to determine the stiffness of an implant in the surrounding tissues. The transducer was designed to be attached to an implant or abutment, and its performance was controlled using a dedicated frequency response analyzer. 
The technique originally used an L-shaped transducer that was screwed to an implant or its abutment. The transducer beam was then excited over a range of frequencies, typically from 5 to 15 KHz. A frequency response analyzer subsequently analyzed the response of the beam. At the first flexural resonance of the beam, there was a marked change in the amplitude and in the phase of the received signal. The resonance frequency can then be identified in a plot of the frequency (Hz) against the amplitude (V). 
Till date four generations of RFA have been introduced. The first generation device was based on a measuring element (transducer) placed on to the implant/abutment and then connected to the measuring unit with a wire. Mounting of the old transducer was often related to problems with limited access for the screwdriver or to a correct positioning of the transducer because of the connection to a wire. For these reasons, it was decided to design a dedicated frequency response analyzer, i.e., a second-generation device. Major drawback of the first- and second-generation RFA devices was that each transducer had its own fundamental resonance frequency. Therefore, different transducers had to be calibrated using a standard before measurements were comparable.  The aim of the third-generation device was to provide a small battery-driven system, which enables quick and simple measurements to be made with the possibility of chairside interpretation. The first commercially available RFA equipment (OsstellTM, Osstell AB, Gothenburg, Sweden) was battery-driven and had new generation of transducer that was precalibrated from the manufacturer. The results are presented as the implant stability quotient. The implant stability quotient unit is based on the underlying resonance frequency and ranges from 1 (lowest stability) to
100 (highest stability). The most recent version of RFA [Figure 1] is wireless, where a metal rod (a peg) is connected to the implant by means of a screw connection [Figure 2]. The peg has a small magnet attached to its top, which is excited by magnetic pulses from a handheld computer. The peg vibrates in two directions, which are approximately perpendicular to each other. The vibration takes place in the direction that gives the highest resonance frequency (first mode) and in the direction that gives the lowest resonance frequency (second mode). Thus, two implant stability quotient values are provided, one high and one low. 
| Literature Review|| |
Meredith and co-workers  found a significant increase in resonance frequency related to increase in stiffness during their in vitro study by embedding implants in self-curing polymethyl methacrylate and measuring the resonance frequency at periods during polymerization to simulate bone around implant during healing. They also found strong correlation between the exposed height of the fixture above the aluminium block and the resonance frequency. They verified all in vitro results with in vivo measurements. Meredith  concluded that RFA being non-invasive, is easy to use clinically and capable of eliciting quantitative information related to implant stability and stiffness. Relation between effective implant length and resonance frequency was proved by Meredith et al.  in 1997 during their study on 56 implants in the maxilla of nine patients.
Friberg and co-workers  found highest correlation when comparing the mean torque values of the upper cortical portion with the RFA measurements at implant placement. They proved that the stability of implants placed in softer bone seems to "catch up" over time with more dense bone sites. RFA technique proved to be more sensitive in detecting changes of implant stability than the conventional clinical and radiographic examination techniques during other clinical study by Friberg et al.  on 75 one-stage Branemark implants. One implant failed in this study and lower resonance frequency value indicated the failure several weeks before the mobility was clinically diagnosed.
Animal study on rabbit by Rasmusson and co-workers  shows that the removal torque technique measures the strength of the bone implant interface in terms of shear, while the RFA is considered to measure the stability during bending. Same thing discussed by Sennerby et al.  saying RFA measurements essentially apply a bending load, which mimics clinical load and direction and provides information about the stiffness of the implant bone junction.
Highest resonance frequency value 36.1 kHz was found when the implant was placed into type I bone and in contrast resonance frequency value of 9.9 kHz was found in type IV bone by Huang et al.  in 2002. Huang and co-workers  use natural frequency to assess implant bone interface and they found that the boundary status of an implant can be monitored by detecting its natural frequency. In other in vivo and in vitro studies on implants, Huang and co-workers  found RFA as a reliable and accurate method for early assessment of osseointegration process. They concluded that these values can not only be used as an indicator for early diagnosis of primary stability but can also provide useful message regarding the secondary stability of implant.
In contrast, Bischof et al.  concluded that RFA method does not provide information on the bone implant interface as the torque test method does. Negative correlation was found between RFA and reverse torque in this study on 106 SLA ITI implants in 36 patients by Bischof and co-workers. They found no effect of implant position, length, diameter, and deepening on primary stability. In contrast to this study, results of study done by Horwitz and co-workers  show a correlation between implant stability quotient and implant diameter. In same study, positive correlation was found between implant stability quotient and insertion torque.
In a study on 48 stepped cylinder implants, Nkenke and co-workers  found more correlation of RFA with histomorphometric parameter than Periotest measurements. They concluded RFA superior to the Periotest in assessing implant stability as a predicator of histomorphometric data. However, negative correlation found between RFA and placement torque in the study on standard Branemark system implants and Branemark TiUnite implants by da Cunhe and co-workers. 
Results of study on 81 Branemark system implants in 23 patients by Glauser and co-workers  shows that failing implants showed a continuous decrease of stability until failure and this information may be used to avoid implant failure by unloading them. In contrast Nedir et al.  concluded that RFA was not reliable in identifying mobile implants; however, implant stability could be reliably determined for implant with an implant stability quotient ≥ 47.
Zix et al.  did study with 120 maxillary ITI implants in 35 patients and found mean implant stability quotient was 52.5±7.9. Men showed higher implant stability than women. They concluded that single RFA measurement of an implant does not allow assessment of its current status. Repeated measurements over a longer period of time would be necessary. Same thing, i.e., single reading using RFA is of limited clinical value as concluded by Aparicio and co-workers. 
Human cadaver study to determine primary stability of orthodontic palatal implants by Gedrange and co-workers  shows that resonance frequency values is affected by both the level of bone and stiffness of interface between implant and bone. However, no indication of stability was seen when evaluated radiographically. In contrast, experimental study in dog by Sennerby and co-workers  revealed a linear relationship between radiographic and RFA findings.
Study on 122 implants in 31 patients revealed weakest implant stability at 3-6 weeks after placement. Ersanli et al.  concluded that implant stability quotient value can be used to determine different healing phases and the stability of dental implants but implant stability quotient level should be calibrated for each implant system separately.
A strong correlation was found between the bone density, the fastening torque and resonance frequency values at implant placement by Turkyilmaz and co-workers  in their study on 158 Branemark system implants in 85 patients. Same results found by Turkyilmaz et al.  in other study done on 30 patients using 60 Branemark system implants. They concluded that both age and gender seems to have effect on both insertion torque and implant stability quotient. Contrary to these results Schliephake and co-workers  were unable to find any correlation between RFA values with the torque required to tap the bone for implant placement. No correlation was found between RFA and bone-implant contact nor between RFA values and peri-implant bone density. Similar results were shown by Veltri et al.  in clinical study on 9 patients with 55 implants. They also found no statistically significant correlation between implant stability quotient and marginal bone level. They also found influence of transducer orientation on the measurement of RFA. In agreement with previous studies Yang and co-workers  were unable to find any correlation between the marginal bone loss and the change of implant stability during their study on 43 implants in 19 patients. However, in a retrospective histological and histomorphometrical study a statistically significant correlation was found between implant stability quotient and bone-implant contact by Scarano and co-workers. 
Mean implant stability quotient of 67.4 was obtained from the study on 905 Branemark dental implants in 267 patients by Ostman et al.  They found higher values for men than women, for mandible than maxilla, for posteriors than anterior sites and for wide platform implants than narrow platform implants. In agreement with this result another retrospective study by Karl et al.  on 385 ITI solid screw implants shows highest stability quotient values for posterior mandible than maxilla. In contrast Huwiler and co-workers  found implant stability quotient values between 57 and 70 represents homeostasis and implant stability during their study on 34 straumann implants. They were unable to find any correlation between implant stability quotient and the classification of bone characteristics given by Lekholm and Zarb in 1985.
Strong correlation between RFA and damping capacity (Periotest) was found by Lachmann and co-workers  in an in vitro study on bovine rib segments of different anatomical origin and densities. They found Periotest instrument showing greater error in clinical application than in vitro experiments. Similar results were shown in another in vitro study by Lachmann et al.  Results showed agreement between measured implant stability and actual loss of peri-implant resin. They found Osstell instrument to be more precise than Periotest device.
Animal study by Al-Nawas and co-workers  using 160 implants shows implant stability quotient at the placement to be more predictive of implant loss than torque measurements. However, they concluded to take caution while judging any implant system on RFA and torque measurements. However, a direct relationship was found between resonance frequency measurements and reverse torque values in an animal study using 40 implants by Buchter and co-workers. 
Alsaadi et al.  found positive relation between subjective assessment of bone quality, i.e., by radiographs and surgeon's tactile sensations, and implant stability quotient values, Periotest values and placement torque measurements at implant insertion during their biomechanical study on 298 patients with 761 TiUnite implants.
A simulation and histomorphometrical animal experiment by Ito et al.  reveals the superiority of RFA in the process of implant treatment and follows up. There was no correlation found between histological implant bone contact and RFA, but study demonstrates, bone at the neck region of implant affects resonance frequency most effectively. By applying controlled boundary conditions during in vivo measurements, a highly positive influence was seen on the repeatability of the Osstell instrument. Study was conducted on guinea pig animal model by Pattijn and co-workers.  They concluded that this improves the possibility of RFA to measure change in the implant bone interface during healing of the implant.
Lai et al.  found primary stability to be affected by bone type. Their study on 104 ITI sand blasted large grit acid etched (SLA) implants shows significantly higher implant stability quotient value for type I bone than type IV bone. Similar results showing strong correlation between the bone density and implant stability quotient were found by Turkyilmaz and co-workers  in their study on human cadavers using 24 implants. In contrast, most recent study by Lai and co-workers  shows no difference in implant stability quotient values between type III and type IV bone at implant placement and follow up. They concluded that residual bone height, implant length and bone type did not seem to affect the implant stability in the clinical situation.
Rabel et al.  found that the implant stability quotient values obtained from different implant systems are not comparable during their study on 602 implants in 263 patients. They also concluded that RFA does not appear suitable for the evaluation of implant stability when used as a single method. Same findings suggested by animal study using 196 implants by Al-Nawas and co-workers.  They found that RFA was influenced majorly by the transducer used, thus prohibiting the comparison of different implant systems.
In a comparative study between the magnetic RFA device and electronic RFA device, Valderrama and co-workers  found both devices correlated well and confirmed the initial decrease in implant stability that occur following placement and identified an increase in stability during the first 6 weeks of functional loading.
In recent studies, statistically significant correlation was shown between insertion torque and implant stability quotient values by Turkyilmaz et al.  They found both insertion torque and implant stability quotient values decrease when the amount of peri-implant vertical bone defect increased. They found linear relationship between peri-implant vertical bone defect depth and RFA values. They proposed to use RFA to monitor healing of peri-implant bone defects. Similar results were shown by another recent study by Tozum and co-workers.  They also found significant correlation between insertion torque and implant stability quotient. They concluded that the wireless resonance frequency analyzer seems to be a suitable and reliable device to determine the implant stability.
In contrast to previous studies one of the recent studies on 24 patients using 64 implants by Boronet et al.  shows higher implant stability quotient values for women than men and for anterior implants than posterior fixtures. They got mean implant stability quotient value for all implants was 62.6 and lowest mean stability measurement was at 4 weeks for all bone types, i.e., 60.9.
| Conclusion|| |
The level of predictability and high success of current implant therapy has provided reasons for reassessing long adopted surgical and prosthetic guidelines. With the trend of shortening treatment time and reducing patient's discomfort and inconvenience, immediate loading implants has emerged as an alternate approach. Certain criteria and guidelines have to be followed to avoid any unnecessary failure.
Primary implant stability is a key factor to consider before attempting immediate implant loading as well as to consider long-term success of implant therapy. So, there is a need for a non-invasive diagnostic technique to clinically assess implant stability and osseointegration. Although extensively used in clinical research as one parameter to monitor implant stability, RFA is still having lot of controversy about its reliability.
A limited number of clinical reports were found. Various studies have demonstrated the feasibility and predictability of the technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are based on short-term results and long-term follow up are still scarce in this field. Nonetheless, from available literature, it may be concluded that RFA technique evaluates implant stability as a function of stiffness of the implant bone interface and is influenced by factors such as bone type, exposed implant height above the alveolar crest. Various studies indicates that implants yield high implant stability quotient values during follow up examinations considered to be successful, while low or decreasing implant stability quotient values may be indicative of developing implant failure of instability.
To conclude RFA could serve as a non-invasive diagnostic tool for detecting the implant stability of dental implants during the healing stages and in subsequent routine follow up care after treatment. Future studies, preferably randomized, prospective longitudinal studies are certainly needed to establish threshold ranges for implant stability and for implants at risk for losing stability for different implant system.
| References|| |
|1.||Branemark PI, Adell R, Breine U, Hansson BO, Lindstrom J, Ohlsson A. Implant osseous anchorage of dental prosthesis: Experimental studies. Scand J Plas Reconst Surg 1969;3:81-100. |
|2.||Branemark PI, Hansson BO, Adell R, Breine U, Lindstrom J, Hallen O, et al. Osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plas Reconst Surg 1977;11:50-3. |
|3.||Adell R, Lekholm U, Rockler B, Branemark PI. A 15 year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;10:387-416. |
|4.||Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long term efficacy of currently used dental implants. A review and proposed criteria of success. Int J Oral Maxillofac implants 1986;1:11-25. |
|5.||Arvidson K, Bystedt H, Frykholm A, Von Konow L, Lothigins E. A 3-year clinical study of Astra dental implants in the treatment of edentulous mandibles. Int J Oral Maxillofac Implants 1992;7:321-9. |
|6.||Albrektsson T. On long term maintenance of the osseointegrated response. Australian Prosthod J 1993;7:15-24. |
|7.||Astrand P, Almfeldt I, Brrinell G, Hemp SE, Hellen S, Karlsson U. Non-submerged implants in the treatment of the edentulous lower jaw- A 2 year longitudinal study. Clin Oral Imp Res 1996;7:337-44. |
|8.||Branemark P I, Zarb G, Albrektsson T. Tissue-integrated prosthesis: osseointegration in clinical dentistry. Chicago: Quintessance; 1985. |
|9.||Gapski R, Wang HL, Mascarenhas P, Lang NP. Critical review of immediate implant loading. Clin Oral Imp Res 2003;14:515-27. |
|10.||Lionbiovine-hack N, Lang NP, Karring T. Significance of primary stability for osseointegration of dental implants. Clin Oral Implants Res 2006;17:244-50. |
|11.||Molly L. Bone density and primary stability in implant therapy. Clin. Oral Implant Res. 2006; 17 (Suppl. 2): 124-135. |
|12.||Sennerby L, Maredith N. Resonance frequency analysis: Measuring implant stability and osseointegration. Compend Contin Educ Dent 1998;19:493-8. |
|13.||Sennerby L, Maredith N. Implant stability measurements using resonance frequency analysis: Biological and Biomechanical aspects and clinical implications. Periodontology 2008;47:51-66. |
|14.||Atsumi M, Park SH, Wang HL. Methods used to assess implant stability: current status. Int J Oral Maxillofac Implants 2007;22:743-54. |
|15.||Aparicio C, Lang NP, Rangert B. Validity and clinical significance of biomechanical testing of implant/bone interface. Clin Oral Implant Res 2006;17:2-7. |
|16.||Meredith N. Assessment of implant stability as a prognostic determinant. Int J Prosthodont 1998;11:491-501. |
|17.||Brunski J. Push out (pull out), tensile and reverse torque tests of bone-implant interfaces. Clin Oral Implant Res 2006;1:33-40. |
|18.||Meredith N, Alleyne D, Cawley P. Quantitative determination of the stability of the implant-tissue interface using resonance frequency analysis. Clin Oral Implant Res 1996;7:261-7. |
|19.||Meredith N, Book K, Friberg B, Jemt T, Sennerby L. Resonance frequency analysis of implant stability in vivo. Clin Oral Implant Res 1997;8:226-33. |
|20.||Friberg B, Sennerby L, Meredith N, Lekholm U. A comparison between cutting torque and resonance frequency measurements of maxillary implants- A 20 month clinical study. Int J Oral Maxillofac Surg 1999;28:297-303. |
|21.||Friberg B, Sennerby L, Linden B, Grondahl K, Lekholm U. Stability measurements of one-stage Branemark implants during healing in mandibles- A clinical resonance frequency analysis study. Int J Oral Maxillofac Surg 1999;28:266-72. |
|22.||Rasmusson L, Merdith N, Cho I H, Sennerby L. The influence of simultaneous versus delayed placement on the stability of titanium implants in onlay bone grafts- A histologic and biomechanic study in the rabbit. Int J Oral Maxillofac Surg 1999;28:224-31. |
|23.||Huang H M, Lee S Y, Yeh C Y, Lin C T. Resonance frequency assessment of dental implant stability with various bone qualities: a numerical approach. Clin Oral Implant Res 2002;13:65-74. |
|24.||Huang HM, Pan LC, Lee SY, Chin CL, Fan KH, Ho KN. Assessing the implant/bone interface by using natural frequency analysis. Oral Surg Oral Med Oral Pahtol Oral Radiol Endod 2000;90:285-91. |
|25.||Huang HM, Chiu CL, Yeh LC, Lin CT, Lin LH, Lee SY. Early detection of implant healing process using resonance frequency analysis. Clin Oral Implant Res 2003;14:437-43. |
|26.||Bischof M, Nedir R, Moncler SS, Bernard JP, Samson J. Implant stability measurement of delayed and immediately loaded implants during healing- A clinical resonance frequency analysis study with SLA ITI implants. Clin. Oral Implant Res 2004;15:529-39. |
|27.||Horwitz J, Zuabi O, Peled M. Resonance frequency analysis in immediate loading of dental implants. Refuat Haper Vehashinayim 2003;20:80-8. |
|28.||Nkenke E, Hahn M, Weinzierl K, Radespiel-Troger M, Engelke K, Neukam FW. Implant stability and histomorphometry: a correlation study in human cadavers using stepped cylinder implants. Clin Oral Implant Res 2003;14:601-09. |
|29.||Da Cunha HA, Frencischone CE, Filho HN, De Oliveira RC. A comparison between CT and RF in the assessment of primary stability and final torque capacity of standard and TiUnite single tooth implants under immediate loading. Int J Oral Maxillofac Implants 2004;19:578-85. |
|30.||Glauser R, Sennerby L, Meredith N, Ree A, Lundgren AK, Gottlow J, et al. Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading: successful vs. failing implants. Clin Oral Implant Res 2004;15:428-34. |
|31.||Nedir R, Bischof M, Szmukler-Moncler S, Bernard J P, Samson J. Predicting osseointegration by means of implant primary stability: A resonance frequency analysis study with delayed and immediately loaded ITI SLA implants. Clin Oral Implant Res 2004;15:520-8. |
|32.||Zix J, Kesiler-Liechti G, Mericska-Stern R. Stability measurements of one-stage implants in the maxilla by means of resonance frequency analysis- a pilot study. Int J Oral Maxillofac Implants 2005;20:747-52. |
|33.||Gedrange T, Hietschold V, Mai R, Wolf P, Nicklisch M, Harzer W. An evaluation of resonance frequency analysis for the determination of the primary stability of Orthodontic palatal implants: A study in human cadavers. Clin Oral Implant Res 2005;16:425-31. |
|34.||Sennerby L, Persson LG, Berglundh T, Wennerberg A, Lindhe J. Implant stability during initiation and resolution of experimental periimplantitis: an experimental study in the dog. Clin Implant Dent Relat Res 2005;7:136-40. |
|35.||Ersanli S, Karabuda C, Beck F, Leblebicioglu B. Resonance frequency analysis of one-stage dental implant stability during the osseointegration period. J Periodontol 2005;76:1066-71. |
|36.||Turkyilmaz I, Tozum TF, Tumer C, Ozbek EN. Assessment of correlation between computerized tomography values of the bone, and maximum torque and resonance frequency values at dental implant placement. J Oral Rehab 2006;33:881-88. |
|37.||Turkyilmaz I. A comparison between insertion torque and resonance frequency in the assessment of torque capacity and primary stability of Branemark system implants. J Oral Rehab 2006;33:754-9. |
|38.||Schliephake H, Sewing A, Aref A. Resonance frequency measurements of implant stability in the dog mandible: experimental comparison with Histomorphometric data. Int J Oral Maxillofac Surg 2006;35:941-6. |
|39.||Veltri M, Balleri P, Ferreri M. Influence of transducer orientation on Osstell TM stability measurements of osseointegrated implants. Clin Implant Dent Related Res 2007;9:60-4. |
|40.||Yang S M, Shin S Y, Kye S B. Relationship between implant stability measured by resonance frequency analysis and bone loss during early healing period. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105: 12-9. |
|41.||Scarano A, Degidi M, Iezzi G, Petrone G, Piattelli A. Correlation between implant stability quotient and bone-implant contact: a retrospective histological and histomorphometrical study of seven titanium implants retrieved from humans. Clin Implant Dent Related Res 2006;8:218-22. |
|42.||Ostman PO, Hellman M, Wendelheg I, Sennerby L. Resonance frequency analysis measurements of implants at placement surgery. Int J Prosthodont 2006;19:77-83. |
|43.||Karl M, Graef F, Heckmann S, Krafft T. Parameters of resonance frequency measurement values: a retrospective study of 385 ITI dental implants. Clin Oral Implant Res 2008;19:214-18. |
|44.||Huwiler MA, Pjetursson BE, Bosshardt DD, Salvi GE, Lang NP. Resonance frequency analysis in relation to jaw bone characteristics and during early healing of implant installation. Clin Oral Implant Res 2007;18:275-80. |
|45.||Lachmann S, Jager B, Axmann D, Gornaz-Roman G, Groten M, Weber H. Resonance frequency analysis and damping capacity assessment. Part I: an in vitro study on measurement reliability and a method of comparison in the determination of primary dental implant stability. Clin Oral Implant Res 2006;17:75-79. |
|46.||Lachmann S, Laval JY, Jager B, Axmann D, Gornaz-Roman G, Groten M, et al. Resonance frequency analysis and damping capacity assessment. Part II: Periimplant bone loss follw-up. An in vitro study with the Periotest and Osstell instruments. Clin Oral Implant Res 2006;17:80-4. |
|47.||Al-Nawas B, Wagner W, Grotz K A. Insertion torque and resonance frequency analysis of dental implant systems in an animal model with loaded implants. Int J Oral Maxillofac Implants 2006;21:726-32. |
|48.||Buchter A, Joos U, Wiesmann H P, Seper L, Mayer U. Biological and biomechanical evaluation of interface reaction at conical screw type implants. Head and Face Medicine 2006;2:1-9. |
|49.||Alsaadi G, Quirynan M, Michiels K, Jacobs R, Steenberghe DV. A biomechanical assessment of the relation between the oral implant stability at insertion and subjective bone quality assessment. J Clin Periodontol 2007;34:359-66. |
|50.||Ito Y, Sato D, Yonada S, Ito D, Kondo H, Kasugai S. Relevance of resonance frequency analysis to evaluate dental implant stability: simulation and histomorphometrical animal experiments. Clin Oral Implant Res 2008;19:9-14. |
|51.||Pattijn V, Jaecques S V, DeSmet E, Muraru L, Van Lierde C, Vander Perre G, et al. Resonance frequency analysis of implants in the guinea pig model: Influence of boundary conditions and orientation of the transducer. Med Eng Phys 2007;29:182-90. |
|52.||Lai HC, Zhuang LF, Zhang ZY. Stability of implants placed in different bone types. Zhonghua Kou Qiang Yi Xue Za Zhi 2007;42:292-3. |
|53.||Turkyilmaz I, Sennerby L, McGlumphy EA, Tozum TF. Biomechanical aspects of primary implant stability: A human cadaver study. Clin Oral Implant Res 2008. |
|54.||Lai HC, Zhang ZY, Wang F, Zhuang LF, Lin X. Resonance frequency analysis of stability on ITI implants with osteotome sinus floor elevation technique without grafting: a 5-month prospective study. Clin Oral Implants Res 2008;19:469-75. |
|55.||Rabel A, Kohler SG, Schmidt-Westhausen AM. Clinical study on the primary stability of two dental implant systems with resonance frequency analysis. Clin Oral Investig 2007;11:257-65. |
|56.||Al-Nawas B, Groetz KA, Goetz H, Duschner H, Wagner W. Comparative histomorphometry and resonance frequency analysis of implants with moderately rough surfaces in a loaded animal model. Clin Oral Implant Res 2008;19:1-8. |
|57.||Valderrama P, Oates TW, Jones AA, Simpson J, Schoolfield JD, Cochran DL. Evaluation of two different resonance frequency devices to detect implant stability: a clinical trial. J Periodontol 2007;78:262-72. |
|58.||Turkyilmaz I, Sennerby L, Yilmaz B, Bilecenoqlu B, Ozbek E N. Influence of defect depth on resonance frequency analysis and insertion torque values for implants placed in fresh extraction sockets: A human cadaver study. Clin Implant Dent Relat Res 2008. |
|59.||Tozum TF, Turkyilmaz I, McGlumphy EA. Relationship between dental implant stability determined by resonance frequency analysis measurements and peri-implant vertical defects: an in vitro study. J Oral Rehabil 2008. |
|60.||Boronat Lopez A, Balaquer Martinez J, Lamas Pelayo J, Carrillo Garcia C, Penarrocha Diago M. Resonance frequency analysis of dental implant stability during the healing period. Med Oral Pathol Oral Cir Buccal 2008;13:244-7. |
Rajiv K Gupta
Department of Prosthodontics, Maulana Azad Institute of Dental Sciences, New Delhi
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]