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 Table of Contents  
Year : 2018  |  Volume : 5  |  Issue : 1  |  Page : 12-16

Dental implant stability: A comparative evaluation between insertion torque and resonance frequency analysis techniques

1 Prosthodontist and Implantologist, Family Dental Care, Bellary, Karnataka, India
2 Prosthodontist and Implantologist, Clove Dental, Hyderabad, Telangana, India
3 Department of Prosthodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutpalli, India
4 Prosthodontist and Implantologist, Safa Multispecialty Dental Clinic, Guntur, Andhra Pradesh, India

Date of Web Publication14-May-2018

Correspondence Address:
Dr. Ravikanth Anne
SF-3, AGS Towers, Srinivasanagar Bank Colony, Vijayawada - 520 008, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdrr.jdrr_66_17

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Aim: The aim of the study was to compare and correlate the primary stabilities of dental implants using torque wrench and resonance frequency analysis (RFA). Materials and Methods: A total of ten patients with partial edentulous condition (Kennedy's Class I, II, and III conditions) in relation to posterior mandibular arch were selected for the study based on inclusion and exclusion criteria. Only the implants positioned in the first molar region were considered for the study (one implant in each patient) to avoid bone density-related bias. Insertion torque values were recorded using a standard spring-loaded torque wrench. RFA at the time of placement was evaluated. Statistical Analysis Used: Linear correlation graph was drawn and statistical analysis was carried out using Mann–Whitney U-test. Results: Statistical analysis between the maximum insertion torque and implant stability quotient (ISQ) values with Mann–Whitney U-test indicated statistical significance (P = 0.0002). Linear correlation graph indicated statistical significance (P = 0.0005; r = 0.8951). Conclusion: Within the limitations of this study, a positive correlation is observed between implant insertion torque and ISQ values measured with RFA.

Keywords: Implant insertion torque, primary stability, resonance frequency analysis

How to cite this article:
Gorantla SD, Peddinti VK, Anne R, Kalluri L. Dental implant stability: A comparative evaluation between insertion torque and resonance frequency analysis techniques. J Dent Res Rev 2018;5:12-6

How to cite this URL:
Gorantla SD, Peddinti VK, Anne R, Kalluri L. Dental implant stability: A comparative evaluation between insertion torque and resonance frequency analysis techniques. J Dent Res Rev [serial online] 2018 [cited 2023 Jan 30];5:12-6. Available from: https://www.jdrr.org/text.asp?2018/5/1/12/232364

  Introduction Top

Modern dentistry aims at restoring the function, comfort, and esthetics of missing tooth. The success of a dental implant depends on its ability to osseointegrate with surrounding bone.[1]Within the clinical perspective, successful osseointegration is quantified on the basis of implant stability.[2]

Implant stability can be categorized as primary implant stability and secondary implant stability. Primary stability, defined as the biometric stability immediately after implant insertion, is a main prognostic tool for the success of dental implants. It is primarily attributed by means of mechanical interlocking of implant with the adjacent cortical bone, which in turn aids in direct bone deposition onto the surface of implant and its mineral tissue integration.[3] The greater the primary stability, the lesser the micromotions between the implant surface and surrounding bone, facilitating uninhibited healing and sound osseointegration.[4]

The traditional gold standard used to assess the status of implant was microscopic and histological analysis. However, owing to invasiveness of this method and the associated ethical issues, various other noninvasive methods are being used such as the surgeon's perception, radiographical analysis, cutting torque resistance, reverse torque, resonance frequency analysis (RFA), modal analysis, and Implatest.[5]

Of all the above-stated methods, RFA introduced by Meredith et al. in 1996 is the widely being used to assess implant stability. RFA is based on the basic vibration theory wherein the response from a transducer that is excited using a steady-state frequency waveform is used to analyze the stiffness of an implant in the surrounding tissues and thus, in turn, assesses the implant stability.[6],[7]

Implant insertion torque is the maximum insertion torque necessary to advance the implant into the prepared bone cavity.[8] In this study, the maximum insertion torque was measured using a calibrated spring-loaded torque wrench.

The present study was done to compare and correlate the RFA values measured using Osstell implant stability quotient (ISQ) instrument, with the insertion torque values (ITV) measured using spring-loaded torque wrench.

  Materials and Methods Top

An in vivo clinical study was conducted in the Department of Prosthodontics, SIBAR Institute of Dental Sciences, Guntur, India. Patients with adequate bone volume, good systemic health, and no smoking habits were included in the study. Ten patients with partial edentulous condition in relation to mandibular arch (Kennedy's Class I, II, and III conditions) were selected. However, only the implants positioned in mandibular first molar region were considered for the study (one implant in each patient) to avoid bone density-related bias. Thorough clinical and laboratory investigations were carried out; patient was informed about the treatment and consent form was obtained. The study was approved by the Institutional Committee.

During the presurgical phase, Sidexis software was used to measure the available bone on digital orthopantomograph. Diagnostic casts were prepared to assess the crown space; ridge mapping was done and transferred to diagnostic casts. An autopolymerizing acrylic stent with acrylic tooth was fabricated. A 2 mm hole is drilled through it matching the prosthetic and surgical centers [Figure 1].
Figure 1: Acrylic stent

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Prophylactic antibiotics were administered before the day of surgery. Standard surgical protocol was performed under aseptic conditions. Sequential drilling was performed using external irrigation with cool saline [Figure 2]. Cortex root form Classix design implant was inserted into the osteotomy site [Figure 3] using cortex spring-loaded torque wrench, and the maximum insertion torque obtained was recorded [Figure 4]. Then, Osstell SmartPeg was fitted to the implant to check the ISQ by RFA [Figure 5]. The values were taken in four directions buccal, lingual/palatal, mesial, and distal and were tabulated.
Figure 2: Pilot drill

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Figure 3: Implant placement

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Figure 4: Measuring stability using torque wrench

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Figure 5: Measuring implant stability quotient using resonance frequency analysis

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Cover screw was placed over the implant after the ITV and ISQ were obtained [Figure 6]. Interrupted sutures were placed [Figure 7]. Postsurgical digital intraoral periapical was taken to assess the implant placement [Figure 8]. Postsurgical antibiotics and nonsteroidal antiinflammatory drugs were prescribed. The data obtained are subjected to statistical analysis.
Figure 6: Placement of cover screw

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Figure 7: Suturing done

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Figure 8: Postoperative intraoral periapical

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  Results Top

The mean ISQ values of each patient and the ITV were statistically analyzed by Spearman Rank correlation method to find the correlation between insertion torque and ISQ values. The average ISQ and ITV values for ten implants placed in this study were determined.

The mean ISQ values as tabulated in [Table 1] were 64.20 ± 8.94 on buccal and palatal/lingual aspects, 63.50 ± 8.62 on mesial aspect, and 63.70 ± 8.71 on distal aspect, respectively. The mean of IT values obtained was 41.50 ± 4.12 and the mean of average ISQ values obtained was 63.90 ± 8.68 [Table 2]. The comparison of values by means of Mann–Whitney U-test [Table 3] is statistically significant (P = 0.0002). The linear correlation [Graph 1] between insertion torque and ISQ values indicated statistical significance for ten implants (P = 0.0005; r = 0.8951). The results show that there is a statistically significant correlation between the maximum insertion torque and resonance frequency values.
Table 1: Mean implant stability quotient values

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Table 2: Mean of average implant stability quotient values

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Table 3: Comparison of implant stability quotient values at different sides and insertion torque (N-Cm) values by Mann-Whitney U-test for 10 implants

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The correlation between the ISQ values on different sides and average ISQ value with the IT value is tabulated in [Table 4]. The Spearman correlation method has given R value and t value when correlated with IT values which were as follows: r = 0.8869, t = 5.4301 for ISQ on buccal side and IT value; r = 0.8319, t = 4.2401 for ISQ on mesial and distal sides and IT values; and r = 0.8951, t = 5.6789 for average ISQ and IT values. The probability values obtained were <0.005 (P< 0.005), which shows a significant correlation between the ISQ and IT values.
Table 4: Correlation between insertion torque with implant stability quotient values at different sides by Spearman rank correlation method for ten implants

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  Discussion Top

The use of dental implants in oral rehabilitation has been increasing significantly owing to their enormous success rate. Successful dental implant outcome may be counted as a result of primary implant stability following placement of dental implants; thus, the implant stability is a key to clinical success. The primary stability of implant in the surrounding bone is crucial in the bone healing, by resisting implant micromovement and the consequent damage to the bone healing process.[8],[9] Micromovement of newly placed implant by any means can endanger the osseointegration process. Thus, it is necessary to attain greater primary stability immediately after implant placement and in the early healing phase until the secondary stability of implant has been achieved through bone remodeling and osseointegration.[10],[11] Primary stability depends on the mechanical engagement of an implant with surrounding bone, and it reduces by time due to the associated bone remodeling of surrounding bone and also due to a reduction in the interfacial strain owing to mechanical stress relaxation within the bone.[12]

Various noninvasive techniques have been proposed to assess the primary implant stability.[5] Of all the techniques proposed, RFA and insertion torque resistance analysis are being used widely to assess primary implant stability.[3],[5] Thus, this study had been carried out to ascertain the correlation between maximum insertion torque and RFA values.

Implant insertion torque is the maximum insertion torque necessary to sink the implant into the prepared bone cavity should ideally range from 35 to 50 Ncm.[13] The energy required in inserting implant is due to the thread placement force from the tip of the instrument, and the friction generated as the implant enters bone.[13],[14] Rajatihaghi et al.[15] in his study has concluded that spring torque wrenches were significantly more accurate than the friction type. Thus, in this study, the maximum insertion torque was measured using a calibrated spring-loaded torque wrench. The implant was torque into the prepared bone cavity by increasing the torque by 5 Ncm incrementally till the implant is completely inserted into the bone cavity.[13] The torque that is obtained when the implant is completely inserted into the bone cavity is the maximum insertion torque which is noted as IT value in this study.

RFA is a widely used clinical, noninvasive measure of implant stability assessment. The magnetic resonance analyzer used in this study consists of a probe that is connected to the ISQ instrument and a SmartPeg, which is a metallic rod with a small magnet on top of it, which can be screwed to the implant or abutment. The transducer probe was held so that the probe tip was aimed at the small magnet on the top of the SmartPeg at a distance of 2–3 mm. The probe was held still during the pulsing time until the instrument beeped and displayed ISQ value. The results of as RFA were expressed as ISQ on a scale from 1 to 100, which represents a standardized unit of stability. In general, the ISQ has been found to vary between 40 and 80 ISQ for clinically stable implants.[7],[16],[17]

The results of the present study are in accordance with the studies conducted by Turkyilmaz,[18] Ohta et al.,[19] and Turkyilmaz et al.,[20] wherein they observed a strong correlation (r = 0.890, P < 0.001) between the insertion torque and resonance frequency values.

However, the present study has certain limitations such as the smaller sample size, limited accuracy of manual torque gauge, and nonavailability of cone-beam computed tomography (CBCT) for accurate assessment of bone density. To overcome the limitations of this study, large sample size could be included; use of CBCT can be considered for accurate bone density measurements and improvement in torque measuring systems, etc.

  Conclusion Top

Within the limitations of this study, it can be concluded that there is a significant correlation between maximum insertion torque and the ISQ as measured using RFA. Furthermore, from the results of this study, it is observed that higher the ISQ value, higher is the implant stability.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Lekholm U, Zarb GA: Patient selection and preparation. In Branemark P-I, Zarb GA, Albrektsson T (Eds.): Tissue Integrated Prosthesis. Osseointegration in Clinical Dentistry. Chicago:Quintessence Publ Co, Inc, 1985:199-209.  Back to cited text no. 1
Linkow LI, Dorfman JD. Implantology in dentistry. A brief historical perspective. N Y State Dent J 1991;57:31-5.  Back to cited text no. 2
Mall N, Dhanasekar B, Aparna IN. Validation of implant stability: A measure of implant permanence. Indian J Dent Res 2011;22:462-7.  Back to cited text no. 3
[PUBMED]  [Full text]  
Trisi P, Perfetti G, Baldoni E, Berardi D, Colagiovanni M, Scogna G, et al. Implant micromotion is related to peak insertion torque and bone density. Clin Oral Implants Res 2009;20:467-71.  Back to cited text no. 4
Atsumi M, Park SH, Wang HL. Methods used to assess implant stability: Current status. Int J Oral Maxillofac Implants 2007;22:743-54.  Back to cited text no. 5
Meredith N, Alleyne D, Cawley P. Quantitative determination of the stability of the implant-tissue interface using resonance frequency analysis. Clin Oral Implants Res 1996;7:261-7.  Back to cited text no. 6
Gupta RK, Padmanabhan TV. Resonance frequency analysis. Indian J Dent Res 2011;22:567-73.  Back to cited text no. 7
[PUBMED]  [Full text]  
Freitas AC Jr., Bonfante EA, Giro G, Janal MN, Coelho PG. The effect of implant design on insertion torque and immediate micromotion. Clin Oral Implants Res 2012;23:113-8.  Back to cited text no. 8
Sotto-Maior BS, Rocha EP, de Almeida EO, Freitas-Júnior AC, Anchieta RB, Del Bel Cury AA, et al. Influence of high insertion torque on implant placement: An anisotropic bone stress analysis. Braz Dent J 2010;21:508-14.  Back to cited text no. 9
Brånemark PI, Hansson BO, Adell R, Breine U, Lindström J, Hallén O, et al. Osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plast Reconstr Surg Suppl 1977;16:1-32.  Back to cited text no. 10
Albrektsson T, Sennerby L, Wennerberg A. State of the art of oral implants. Periodontol 2000 2008;47:15-26.  Back to cited text no. 11
Cehreli MC, Karasoy D, Akca K, Eckert SE. Meta-analysis of methods used to assess implant stability. Int J Oral Maxillofac Implants 2009;24:1015-32.  Back to cited text no. 12
Goswami MM, Kumar M, Vats A, Bansal AS. Evaluation of dental implant insertion torque using a manual ratchet. Med J Armed Forces India 2015;71:S327-32.  Back to cited text no. 13
Gutierrez J, Nicholls JI, Libman WJ, Butson TJ. Accuracy of the implant torque wrench following time in clinical service. Int J Prosthodont 1997;10:562-7.  Back to cited text no. 14
Rajatihaghi H, Ghanbarzadeh J, Daneshsani N, Sahebalam R, Nakhaee M. The Accuracy of Various Torque Wrenches Used in Dental Implant Systems. J Dent Mater Tech 2013;2:38-44.  Back to cited text no. 15
Meredith N. Assessment of implant stability as a prognostic determinant. Int J Prosthodont 1998;11:491-501.  Back to cited text no. 16
Quesada-García MP, Prados-Sánchez E, Olmedo-Gaya MV, Muñoz-Soto E, González-Rodríguez MP, Valllecillo-Capilla M, et al. Measurement of dental implant stability by resonance frequency analysis: A review of the literature. Med Oral Patol Oral Cir Bucal 2009;14:e538-46.  Back to cited text no. 17
Turkyilmaz I. A comparison between insertion torque and resonance frequency in the assessment of torque capacity and primary stability of Brånemark system implants. J Oral Rehabil 2006;33:754-9.  Back to cited text no. 18
Ohta K, Takechi M, Minami M, Shigeishi H, Hiraoka M, Nishimura M, et al. Influence of factors related to implant stability detected by wireless resonance frequency analysis device. J Oral Rehabil 2010;37:131-7.  Back to cited text no. 19
Turkyilmaz I, Sennerby L, Yilmaz B, Bilecenoglu B, Ozbek EN. 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 2009;11:52-8.  Back to cited text no. 20


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]

  [Table 1], [Table 2], [Table 3], [Table 4]


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