Take-home messages

  • The bone density measurement system devised by IDI Evolution applies a fundamental insight, already noted in 1995 by two renowned implantologists – Lars Sennerby and Bertil Friberg: bone resistance to cutting measures its density.
  • Starting from this insight, IDI Evolution has endowed a specific a special instant torque measuring micromotor with a bone density measurement probe, to be used after passing the initial drill for implant tunnel preparation, while the motor measures the instant torque required to allow its descent into the tunnel at a constant speed. The average of all the instant torque values has been shown to be a reliable bone density estimator.
  • Initial exploratory studies immediately demonstrated that the system could distinguish the four bone density areas empirically known, through Misch's classification, to all implantologists: upper posterior, upper anterior; lower posterior, lower anterior. With a fundamental difference: such finding was no longer empirical but objective because it was achieved through quantitative measurements.
  • The validity of the device and its measuring system was confirmed by a research done in collaboration with Prof. Piattelli's group at the University of Chieti: the measurements are independent of the operator performing them. The system yields the same results regardless of who is using it.

Already in 1995, Lars Sennerby and Bertil Friberg had proposed and demonstrated the validity of the hypothesis that the resistance offered by bone to implant threads could be correlated with bone density, publishing some fundamental works on the subject.

The discovery, while of interest to research, had little clinical impact: at the time of implant insertion, there is no way to adapt the implant tunnel, and bone density measurement at that moment, although quantitative, is not more meaningful for the oral surgeon.

However, starting from this concept, IDI Evolution hypothesized that the same principle could be exploited at a time when the implant tunnel could still be modified: after passing the initial drill. It thus created a special probe, with a diameter of 2.3 mm, to be associated with the TMM3 motor, capable of measuring the instant torque needed to make it rotate at a constant speed while descending into the tunnel. It then hypothesized, following in the footsteps of Sennerby and Friberg, that the average value of all such instantaneous torque values could be a reliable bone density estimator.

Clinical researchers close to IDI Evolution began collecting data. The first confirmation that the intuition was correct came from their analysis: bone density measurements collected with the motor exactly replicated what was already known about maxillary density – that is, that the anterior sectors are denser than the posterior ones, and that the mandible is denser than the maxilla.

Still, while the existence of the four areas had long been known to all implantologists empirically, based on tactile sensation during drilling (the well-known Misch classes, with perceptual sensation compared to drilling... different types of wood!), the motor instead provided numerical, precise, objective data. Thus, an objective, numerical, and, above all, site-specific bone density measurement was born.

With these initial works, a line of research has been opened that has continued uninterrupted for more than 10 years: that of intra-operative, site-specific, and operator-independent bone density measurement.

We mention three pioneering works: in 2013, Prof. Di Stefano and other researchers published the first evidence of the system's validity, showing how the motor quantitatively and objectively distinguishes the four areas (upper, posterior, and anterior; lower, posterior, and anterior) already empirically known to every implantologist; in 2015, Dr. Arosio published a first case showing how objective density measurement could serve as a rational guide for implant site preparation to achieve the desired primary stability predictably; again in 2015, Prof. Di Stefano and the University of Chieti group led by Prof. Piattelli showed how density measurements provided by the motor are independent of the operator performing them, demonstrating that the TMM3 motor is a true measurement tool, providing objective data regardless of the operator using it.

References

Di Stefano DA, Arosio P, Pagnutti S. A possible novel objective intraoperative measurement of maxillary bone density. Minerva Stomatol. 2013 Jul-Aug;62(7-8):259-65. 
Link to the article
IF: 1,400 (2025)

Arosio P, Moschioni M, Banfi LM, Di Stefano DA. An Intraoperative Site-specific Bone Density Device: A Pilot Test Case. J Contemp Dent Pract. 2015 Aug 1;16(8):697-703. doi: 10.5005/jp-journals-10024-1743.
Link to the article

Di Stefano DA, Arosio P, Piattelli A, Perrotti V, Iezzi G. A torque-measuring micromotor provides operator independent measurements marking four different density areas in maxillae. J Adv Prosthodont. 2015 Feb;7(1):51-5. doi: 10.4047/jap.2015.7.1.51. 
Link to the article 
IF: 2,000 (2025)

 


Bone density measurement is performed using a probe that is lowered at a constant speed into a first tunnel, which can then be widened based on the bone density reading. The initial exploratory works, aimed at verifying the validity of measuring density as described, immediately highlighted how the system was able to distinguish the well-known four density areas also empirically found in maxillae using Misch's classification, but in an objective, reproducible, and operator-independent manner.

What is the importance for clinical research?

These results, beyond their immediate applicability in daily practice, are fundamental for clinical research. They pave the way to the possibility of performing a site-specific measurement of bone density exactly where the implant will be placed. The tactile evaluation is finally abandoned, and researchers can now rely on an objective bone density measurement system. The researcher who wants to conduct studies on parameters dependent on bone density (given an implant system and a certain bone density, investigate what is the best preparation protocol; study how implant stability varies according to its diameter and length, shape, thread design, given a certain bone density, etc.) can collect objective density data, completely eliminating the subjectivity of tactile evaluation.

What is the impact on everyday practice?

  • The surgeon can exploit a tool that provides an objective bone density measurement: this piece of information allows confirming or modulating the diagnosis regarding bone quality already formulated on CBCT scans and gives the surgeon complete awareness when preparing the implant site.
  • The surgical procedure becomes less empirical, less subjective, and therefore more predictable, allowing greater repeatability and reproducibility and a higher probability of success, ensuring a more positive outcome for the patient.
  • The implant positioning is adapted in relation to the objective diagnosis of bone density of that specific patient, just where the implant will be placed.

In support of IDI Evolution devices:

TMM3 gives the surgeon the ability to carry out a bone density diagnosis through objective measurements; the graph produced by the motor while the probe enters the first tunnel, to later be adapted based on the reading, provides additional qualitative information, complementing those already acquired by analyzing the patient's CBCT scans.

TMM3 thus completely eliminates any subjectivity, both as far as the operator is concerned, who is no longer forced to rely on their manual sensitivity, and in relation to different operators, all of whom obtain the same result, when performing the measurement on the same bone tissue.

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