Rapid advances in surgical techniques and equipment, as well as an ever-developing body of evidence around the mechanisms involved in osseointegration, have made dental implants an increasingly predictable treatment for edentulism. There is now an array of options for successful treatment in all bone types.[i]
Despite an impressive success rate, now estimated to be over 97%,[ii] failure can still occur, and complications can be a barrier to treatment. Overall, primary, or mechanical stability is the best indicator of implant success, alongside the patient’s capacity to heal.[iii]
Clinicians have to consider the impact of putting a healing implant under stress when deciding on loading protocols, and decisions are dependent on secondary, or biological stability. This is determined through bone regeneration and remodelling resulting in osseointegration, and is largely influenced by the factors related to the design, material and surface treatment of the implant, as well as the quality and quantity of the bone.[iv] For example, the length[v], width[vi] and surface texture of implants[vii] influences survival rates, and bone quality is of vital importance, particularly in the first 4 to 12 weeks of healing.[viii]
Measuring stability
Two well-accepted measures of implant stability are the insertion torque value (ITV), and the implant stability quotient (ISQ) through resonance frequency analysis (RFA).[ix] Reverse torque was conventionally the first measure used to confirm integration. However, torque is a measure of frictional rotation, not a measure of stability, which is resistance to micromovement. Although torque doesn’t register the variable morphology of bone around an implant, it can be a valuable addition to radiological and clinical examination.[x] However, ISQ is the only way to tell if implants can resist micromovement, and is now believed to have a greater predictive power for the clinical outcome than ITV.[xi]
ISQ is an effective means to establish a baseline and subsequently to identify trends in a patient’s healing process which provide indications for the best loading protocols. When used in conjunction with clinical judgement and other measures, monitoring ISQ is the best predictor of biological stability.[xii]
RFA to establish ISQ is performed by measuring the response of an implant-retained piezo-ceramic element to vibration. The peak amplitude of the response is then converted into ISQ values in a range from 0 to 100.[xiii] The range between 60 and 70 is of greatest significance when planning treatment, as we will examine in further detail.[xiv]
The ISQ workflow
As Dr Aly Virani said in a recent webinar on ISQ, loading protocols, and the role of progressive loading: “An integration check at placement is essential for ISQ readings during the healing process to be truly useful. The narrative offered by multiple readings is one of the main advantages of ISQ monitoring. For example, if an implant has shown a medium-high ISQ at placement, but then a medium-low one after four weeks, this shows a decline in stability, whereas, if a low ISQ reading at placement then becomes a medium-low one, this demonstrates positive progress. The implant may simply require more time to integrate.”
Where ISQ is less than 60 at placement, the implant may need to be submerged below the soft tissue, and may require a longer healing period, with regular tests to determine progress. Delayed, early or progressive loading can be considered, depending on the quality of bone, once an ISQ value above 60 has been determined.[xv]
Any reading above 70 is considered high stability, and can provide an optimal basis for immediate loading protocols.[xvi] Dr Virani added: “ISQ is perhaps most useful when monitoring implants in the middle range, or when implants are heading for failure due to compromised healing, medications or underlying medical conditions.”
The advantages of progressive loading with low-medium ISQ
Bone quality is of prime importance during the osseointegration process, and where it is less dense, progressively loaded implants have a number of advantages. ISQ is the most useful tool in implementing this treatment type. Studies have shown that progressively loaded implants show a continuous increase in peri-implant bone density,[xvii] due to a phenomenon known as Wolff’s Law. This is where trabecular and cortical bone strengthens as an adaptation to stress caused by mechanical loading.[xviii]
This practice has also been called “bone training” for its potential to strengthen bone. A clinician can manipulate the process by slowly increasing the stress on the maturing bone, allowing time for the bone to increase in density and thus be able to withstand the subsequent higher loading.[xix] The ISQ testing process of periodically removing a healing abutment to test can in itself contribute to this healing process.
Determining stability with the best tools available
The Osstell Beacon from W&H is a fast and non-invasive tool used to determine ISQ reliably and intuitively. The Osstell Beacon works with the free, cloud-based analysis software, Osstell Connect, to easily determine which implants can be treated and which require additional healing time, providing documentation for sharing and review. The Osstell Beacon also works seamlessly with the Implantmed surgical unit and Piezomed piezo surgery device, offering a full surgical solution.
With increasingly accurate tools and greater knowledge of the processes around optimal osseointegration, using ISQ as a measure throughout the treatment process gives both clinician and patient greater certainty and confidence.
To find out more visit www.wh.com/en_uk, call 01727 874990 or email office.uk@wh.com
Author: Kate Scheer, W&H Marketing Executive
[i] Ranjan Gupta; Neha Gupta; Kurt K. Weber, DDS. Dental Implants. StatPearls Publishing. January 2024. Available at: https://www.ncbi.nlm.nih.gov/books/NBK470448/ Accessed June 2024.
[ii] Kochar SP, Reche A, Paul P. The Etiology and Management of Dental Implant Failure: A Review. Cureus. 2022 Oct 19;14(10):e30455. doi: 10.7759/cureus.30455. PMID: 36415394; PMCID: PMC9674049.
[iii] Kochar SP, Reche A, Paul P. The Etiology and Management of Dental Implant Failure: A Review. Cureus. 2022 Oct 19;14(10):e30455. doi: 10.7759/cureus.30455. PMID: 36415394; PMCID: PMC9674049.
[iv] Sarfaraz H, Johri S, Sucheta P, Rao S. Study to assess the relationship between insertion torque value and implant stability quotient and its influence on timing of functional implant loading. J Indian Prosthodont Soc. 2018 Apr-Jun;18(2):139-146. doi: 10.4103/jips.jips_203_17. PMID: 29692567; PMCID: PMC5903177.
[v] Gómez-Polo M, Ortega R, Gómez-Polo C, Martín C, Celemín A, Del Río J. Does Length, Diameter, or Bone Quality Affect Primary and Secondary Stability in Self-Tapping Dental Implants? J Oral Maxillofac Surg. 2016 Jul;74(7):1344-53. doi: 10.1016/j.joms.2016.03.011. Epub 2016 Mar 22. PMID: 27070843.
[vi] Barikani H, Rashtak S, Akbari S, Badri S, Daneshparvar N, Rokn A. The effect of implant length and diameter on the primary stability in different bone types. J Dent (Tehran). 2013 Sep;10(5):449-55. Epub 2013 Sep 30. PMID: 24910653; PMCID: PMC4025419.
[vii] H H, G W, E H. The clinical significance of implant stability quotient (ISQ) measurements: A literature review. J Oral Biol Craniofac Res. 2020 Oct-Dec;10(4):629-638. doi: 10.1016/j.jobcr.2020.07.004. Epub 2020 Aug 14. PMID: 32983857; PMCID: PMC7494467.
[viii] H H, G W, E H. The clinical significance of implant stability quotient (ISQ) measurements: A literature review. J Oral Biol Craniofac Res. 2020 Oct-Dec;10(4):629-638. doi: 10.1016/j.jobcr.2020.07.004. Epub 2020 Aug 14. PMID: 32983857; PMCID: PMC7494467.
[ix] Sarfaraz H, Johri S, Sucheta P, Rao S. Study to assess the relationship between insertion torque value and implant stability quotient and its influence on timing of functional implant loading. J Indian Prosthodont Soc. 2018 Apr-Jun;18(2):139-146. doi: 10.4103/jips.jips_203_17. PMID: 29692567; PMCID: PMC5903177.
[x] Sarfaraz H, Johri S, Sucheta P, Rao S. Study to assess the relationship between insertion torque value and implant stability quotient and its influence on timing of functional implant loading. J Indian Prosthodont Soc. 2018 Apr-Jun;18(2):139-146. doi: 10.4103/jips.jips_203_17. PMID: 29692567; PMCID: PMC5903177.
[xi] H H, G W, E H. The clinical significance of implant stability quotient (ISQ) measurements: A literature review. J Oral Biol Craniofac Res. 2020 Oct-Dec;10(4):629-638. doi: 10.1016/j.jobcr.2020.07.004. Epub 2020 Aug 14. PMID: 32983857; PMCID: PMC7494467.
[xii] https://view6.workcast.net/AuditoriumAuthenticator.aspx?cpak=2000973112847507&pak=2678508770806964
[xiii] H H, G W, E H. The clinical significance of implant stability quotient (ISQ) measurements: A literature review. J Oral Biol Craniofac Res. 2020 Oct-Dec;10(4):629-638. doi: 10.1016/j.jobcr.2020.07.004. Epub 2020 Aug 14. PMID: 32983857; PMCID: PMC7494467.
[xiv] do Vale Souza JP, de Moraes Melo Neto CL, Piacenza LT, Freitas da Silva EV, de Melo Moreno AL, Penitente PA, Brunetto JL, Dos Santos DM, Goiato MC. Relation Between Insertion Torque and Implant Stability Quotient: A Clinical Study. Eur J Dent. 2021 Oct;15(4):618-623. doi: 10.1055/s-0041-1725575. Epub 2021 Jul 7. PMID: 34233364; PMCID: PMC8630976.
[xv] Ranabhatt R, Singh K, Siddharth R, Tripathi S, Arya D. A randomized clinical study to compare implant stability and bone loss using early loading protocol in two implant systems with different design. J Indian Prosthodont Soc. 2021 Jan-Mar;21(1):74-80. doi: 10.4103/jips.jips_297_20. PMID: 33835071; PMCID: PMC8061433.
[xvi] do Vale Souza JP, de Moraes Melo Neto CL, Piacenza LT, Freitas da Silva EV, de Melo Moreno AL, Penitente PA, Brunetto JL, Dos Santos DM, Goiato MC. Relation Between Insertion Torque and Implant Stability Quotient: A Clinical Study. Eur J Dent. 2021 Oct;15(4):618-623. doi: 10.1055/s-0041-1725575. Epub 2021 Jul 7. PMID: 34233364; PMCID: PMC8630976.
[xvii] Appleton RS, Nummikoski PV, Pigno MA, Cronin RJ, Chung KH. A radiographic assessment of progressive loading on bone around single osseointegrated implants in the posterior maxilla. Clin Oral Implants Res. 2005 Apr;16(2):161-7. doi: 10.1111/j.1600-0501.2004.01089.x. PMID: 15777325.
[xviii] Paul Rowe; Adam Koller; Sandeep Sharma. StatPearls. Physiology, Bone Remodeling March 2023. Available at: https://www.ncbi.nlm.nih.gov/books/NBK499863/ Accessed June 2024.
[xix] Turner PS, Nentwig GH. Evaluation of the value of bone training (progressive bone loading) by using the Periotest: A clinical study. Contemp Clin Dent. 2014 Oct;5(4):461-5. doi: 10.4103/0976-237X.142811. PMID: 25395760; PMCID: PMC4229753.
