Take-home messages

  • 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.
  • This paves the way for rational and quantitative studies aimed at providing objective criteria for cortical undersizing to achieve reproducible primary stability and predict the outcome in terms of short- and long-term marginal bone resorption.

The demonstration in 2021 and 2024 that the IDI Evolution bone density diagnosis system can discriminate between different cortico-cancellous combinations, besides paving the way to a possible new objective bone density classification, allows to address a new line of research: the rational undersizing of the cortical layer. In 2022, a systematic literature review carried out in collaboration with the research group of the Vita-Salute University definitively highlighted how cortical thickness is rarely taken into consideration when deciding how to prepare the site for implant placement.

Furthermore, the literature review highlighted how studies on the extent of cortical preparation are few and have conflicting results, both in relation to the achievable primary stability and the marginal bone loss (MBL) that cortical undersizing can induce in the short and long term.

Studies conducted in 2021 and 2024, however, showed that the IDI system is capable of objectively and quantitatively discriminating different combinations of cortical thickness and cancellous density; in 2018, it was also shown to quantitatively measure the mechanical stress that the cortical undergoes during implant placement. This paves the way to carrying out clinical studies specifically designed to understand how much a certain undersizing of the cortical layer stabilizes the implant immediately after its placement, and whether and how much it influences both the immediate and long-term marginal bone resorption. These studies could provide objective criteria for cortical undersizing, making the clinical procedure reproducible and predictable, in terms of both primary stability and MBL – a result that would significantly change the daily practice of oral implant surgeons.

References

Arosio P, Sartori M, Arosio F, Garagiola U, Di Stefano DA. Using a Bone Density Measuring Micromotor to Distinguish Different Cortical/Cancellous Combinations in Vitro: A Study Using Polyurethane Foam Blocks. Int J Oral Maxillofac Implants. 2024 Apr 24;39(2):310-318. doi: 10.11607/jomi.10467.
Link to the article
IF: 2,000 (2025)

Di Stefano DA, Piattelli A, Iezzi G, Orlando F, Arosio P. Cortical Thickness, Bone Density, and the Insertion Torque/Depth Integral: A Study Using Polyurethane Foam Blocks. Int J Oral Maxillofac Implants. 2021 May-Jun;36(3):423-431. doi: 10.11607/jomi.8419.
Link to the article
IF: 2,000 (2025)

Di Stefano DA, Arosio P, Capparè P, Barbon S, Gherlone EF. Stability of Dental Implants and Thickness of Cortical Bone: Clinical Research and Future Perspectives. A Systematic Review. Materials (Basel). 2021 Nov 25;14(23):7183. doi: 10.3390/ma14237183.
Link to the article
IF: 3,700 (2025)

Andreasi Bassi M, Arosio P, Di Stefano DA. Evaluation of Peri-implant Bone Stress on D1 Bone Using a Computerized Torque-Measuring Implant Motor: A Study on Photoelastic Resin Blocks. Int J Oral Maxillofac Implants. 2018 July/August;33(4):770–778. doi: 10.11607/jomi.6079.
Link to the article
IF: 2,000 (2025)

What is the importance for clinical research?

To date, no one has fully understood how undersizing a cortical layer having a given thickness changes, for a particular type of implant, its primary stability and its short- and long-term marginal bone loss. Using the IDI Evolution bone density and primary stability measurement system allows to design, for the first time, investigations aimed to gather quantitative and reproducible measurements that could definitively clarify this relationship. These studies could lead to the definition of objective criteria for cortical undersizing, making the clinical procedure reproducible and predictable as far as the implant primary stability and MBL are concerned.

What is the impact on everyday practice?

When protocols for cortical undersizing will be introduced,  the TMM3 system, will provide the oral surgeons not only with a site-specific, objective, and independent system for measuring bone density and quality and primary stability through a dynamic parameter, the Integral - but also with guidance about the extent of cortical undersizing to be used to achieve the desired primary stability safely with respect to short- and long-term MBL.

In support of IDI Evolution devices

Using TMM3 already means exploiting an objective and operator-independent system for site-specific measurement of bone quality, and to assess primary stability through a dynamic measurement parameter more informative than IT or ISQ. This, especially if fully characterized implants are used, as those provided by IDI Evolution, makes the implant insertion procedure objective, reproducible, and predictable in its outcome. This could soon be supplemented by the possibility of performing targeted and objective cortical undersizing according to rational and validated criteria.

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