Take-home Messages

  • The Integral of the torque-depth curve, measured by TMM3 during implant insertions, varies predictably in relation to how underprepared the implant tunnel is.
  • The variation of the Integral is also predictable when altering the implant geometry, both in terms of shape (conical, cylindrical, etc.) and dimensions (diameter/length).
  • The mathematical algorithms describing these variations are also influenced by bone density.
  • Thus, given a certain bone density measured with TMM3, it is possible to quantitatively predict how each of the other factors affects the primary stability that can be achieved—provided that the implant system has been characterized beforehand.

Once the Integral of the torque-depth curve was shown to be more sensitive to variations in bone density than the insertion torque (IT) and the implant stability quotient (ISQ), and it was validated through studies about its correlation with the Bone-to-Implant Contact (BIC), IDI Evolution initiated a series of studies aimed at determining whether and how the Integral varies in relation to the implant site preparation and the morphological characteristics of the implant, both in terms of its shape (cylindrical, conical, etc.) and its dimensions (diameter, length).

The importance of these studies cannot be overstated. If the Integral varies depending on the implant site preparation (i.e., transitioning from normal preparation to undersizing or tapping), one could possibly know in advance how stability will change according to how the tunnel preparation is modified. Similarly, if the Integral varies with changes in implant morphology, it would be possible to quantitatively predict how choosing a particular implant shape (e.g., cylindrical, conical, etc.) and its dimensions (diameter, length) will modulate primary stability, thus achieving the desired primary stability value that allows the safest application of the most appropriate implant loading protocol.

Indeed, in 2018, a study conducted in collaboration with Prof. Piattelli's group at the University of Chieti showed that the Integral varies linearly depending on the extent of undersizing of the implant site, allowing precise measurement of how much undersizing is needed to achieve the desired increase in stability for a given type of implant. It also showed that the Integral distinguishes the tapping condition even when tapping leads to the same BIC achievable with a normal preparation, further highlighting its significance as a measure of primary stability and as an estimator of the bone-implant energy exchange.

In 2019, the same research group showed how the Integral distinguishes changes in stability caused by using different implant morphologies (cylindrical, modified cylindrical, conical-cylindrical), thus showing that each implant system can be characterized by a distinctive stability-density curve. The same study also demonstrated how the Integral provides different, dynamic information from that obtainable from IT or ISQ.

Again in 2019, another study, conducted by Prof. Di Stefano and Dr. Arosio, showed how the Integral, after choosing a given implant shape, accurately measures, for each encountered bone density, the increase in primary stability achievable by increasing the diameter and/or length of the fixture, and also showed that a unitary increase in diameter is significantly more stabilizing than a unitary increase length.

The implications of these studies are many. Beyond further validating the Integral as an estimator of primary stability, they show that it is truly possible to objectively quantify how each variable of implant insertion modulates, for a given type of implant, its primary stability: how the site is prepared, the extent of undersizing, the implant shape, its length, and its diameter.

References

Arosio P, Arosio F, Di Stefano DA. Implant Diameter, Length, and the Insertion Torque/Depth Integral: A Study Using Polyurethane Foam Blocks. Dent J (Basel). 2020 Jun 4;8(2):56. doi: 10.3390/dj8020056
Link to the article
IF: 3,400 (2025)

Di Stefano DA, Arosio P, Perrotti V, Iezzi G, Scarano A, Piattelli A. Correlation between Implant Geometry, Bone Density, and the Insertion Torque/Depth Integral: A Study on Bovine Ribs. Dent J (Basel). 2019 Mar 5;7(1):25. doi: 10.3390/dj7010025
Link to the article 
IF: 3,400 (2025)

Di Stefano DA, Perrotti V, Greco GB, Cappucci C, Arosio P, Piattelli A, Iezzi G. The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs. J Adv Prosthodont. 2018 Jun;10(3):227-235. doi: 10.4047/jap.2018.10.3.227.
Link to the article
IF: 2,000 (2025)

 


The plot on the left shows how BIC does not vary when undersizing or tapping the implant site compared to normal site preparation. In both cases, even if exerting a different pressure on bone, the implant gets in touch with a similar, not statistically different, bone quantity. The situation is different concerning the Integral: the energy exchanged in the two situation is different, and the difference is statistically significant. The Integral, thus, distinguishes between different preparation, even when the bone to implant contact area is the same.

What is the importance for Clinical Research?

  • Researchers measuring implant primary stability using TMM3 through the Integral of the torque-depth curve benefit from a dynamic estimator that precisely assess the energy the implant exchanges with the bone tissue during its placement, whether it's dispersed as heat due to friction, retained as elastic compression energy, or utilized in trabecular anelastic deformation.
  • Every insertion variable can be quantitatively studied in relation to its effect on energy exchange and implant primary stability.
  • Consequently, researchers can now, for any type of implant, construct specific primary stability-bone density curves in relation to the site preparation and fixture dimensions, thus achieving a precise and comprehensive system characterization.
  • During fixture development, researchers can modulate its geometry and accurately measure how the introduced modification impacts primary stability, thereby optimizing the overall design.

What is the impact on Daily Operations:

  • Surgeons utilizing IDI Evolution TMM3 for implant insertions and positioning IDI Evolution implants, can rely on completely characterized implant systems.
  • They will use TMM3 to measure bone density in a site-specific manner and, having defined the dimensions of the implant to be placed, they will benefit from the precise prediction of mathematical algorithms that will suggest how to prepare the implant site to achieve the desired primary stability. They can also, if desired, verify whether and how, given a certain density and site preparation mode, primary stability will vary by modifying the dimensions of the implant to be placed. They will operate not only consciously but also predictably, thereby increasing the likelihood of success of the entire rehabilitation. 

In Support of IDI Evolution Devices

By employing TMM3 in the context of implant placement, every step is rational and translates into quantitative and objective measures: from site-specific bone density determination to primary stability measurement through the Integral, a parameter more sensitive to bone density variations than IT and ISQ. The TMM3 predictive mathematical algorithms, derived from the many scientific studies conducted, calculate in advance how primary stability varies when, given a certain bone density and chosen any IDI Evolution implant, and its dimensions, the implant site preparation is modulated. This allows the surgeon to predict the primary stability that will be achieved with that specific implant-preparation combination and therefore to modulate the preparation protocol, if necessary.

Other Publications

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We have paved the way to provide objective protocols for undersizing the cortical layer, making the clinical procedure reproducible, and the outcome predictable in terms of MBL

The relationship between the extent of cortical undersizing, the primary stability it allows to achieve, the early and late marginal bone resorption it may induce has still not been clarified: studies on this matter are contradictory and inconclusive.
However, IDI Evolution systems are the only ones capable of site-specific discrimination and operator-independent assessment of different combinations of cortical thickness and cancellous density, providing a measure of implant primary stability, the Torque-Depth Integral, which also evaluates the mechanical stress exerted on the cortical thickness.

Read moreabout We have paved the way to provide objective protocols for undersizing the cortical layer, making the clinical procedure reproducible, and the outcome predictable in terms of MBL

We have demonstrated that the IDI bone density diagnosis system can distinguish between different cortical-trabecular combinations, paving the way for a new objective bone classification

The research carried out by IDI Evolution shows that TMM3 measures even bone quality, that is the combination of a given cortical layer thickness and a given trabecular density.

Read moreabout We have demonstrated that the IDI bone density diagnosis system can distinguish between different cortical-trabecular combinations, paving the way for a new objective bone classification

We have defined an objective method for rationally choosing both the protocol for preparing the implant site and the shape and dimensions of the implant to be used

The Integral of the torque-depth curve, measured by TMM3 during implant insertions, varies predictably in relation to how underprepared the implant tunnel is.
The variation of the Integral is also predictable when altering the implant geometry, both in terms of shape (conical, cylindrical, etc.) and dimensions (diameter/length).
The mathematical algorithms describing these variations are also influenced by bone density.

Read moreabout We have defined an objective method for rationally choosing both the protocol for preparing the implant site and the shape and dimensions of the implant to be used