When a surgeon plans his intervention, he would like to be sure that the implant positioned in the patient's mouth will have exactly the same position as virtually planned. In general, when surgeons wish to be sure of that, they try to approach guided surgery. But, is it conventional guided surgery really able to let them meet their needs?
With the conventional guided surgery, the position of the drill is guided by the contact of the drill or of a portion of it with the sleeve fixed to the template.
But in most cases the first contact of the drill with the bone occurs when the driving portion of the drill isn't yet in contact with the sleeve.
Therefore, the precision of the initial positioning depends on the surgeon's hand, which is the only instrument to try to keep the drill exactly in the middle of the sleeve. Unless the surgeon is able to do that (by the way it's almost impossible) the first hole will be more or less eccentric. Further drilling will make the hole more centric, but always with some necessary limits in the precision (see below).
Furthermore, in order to be able to rotate into the sleeves, the drills must necessarily have a clearance that allows rotation without the risk of seizure.
Due to this reason, the precision in the direction of the drill can be much less than expected.
The clearance is needed in order to allow the rotation of the instruments, but it also may cause errors:
* in inclination (on average 3.84 ± 1.49°) and position of the implants (on average 0.45 ± 0.48 mm horizontally and 0.63 ± 0.51 mm vertically at the implant neck and 0.70 ± 0.63 mm horizontally and 0.64 ± 0.57 mm vertically at the implant apex).
** The mean angular deviation was 2.72° ± 1.42. The mean threedimensional deviation at the implant's entry point was 0.75 mm ± 0.34. At implant's apex, the mean was 1.06 mm ± 0.44.
* Moon et al. Maxillofacial Plastic and Reconstructive Surgery (2016) 38:15 - DOI 10.1186/s40902-016-0063-3
** Derksen et al. Clinical Oral Implants Research / Volume 30, Issue 10 (2019) 1005:1015 - https://doi.org/10.1111/clr.13514
Which advantages in the precision offers Toltac®system?
When a mechanician needs to do precise holes, never uses a drill with his free hands: he always uses a drill press.
The idea of Toltac® gives to the surgeons a mechanic way to drive their drills which is somewhat similar to a drill press, therefore offering great advantages in the precision.
first advantage of Toltac®system:
early guide of the drill
With Toltac® the first contact of the drill with the bone occurs when the drill is already guided, therefore it is already perfectly aligned with the planned implant's axis
If what we wish is to fix two implants perfectly parallel to one another, with Toltac® it's easier than freehand. If the bone amount is adequate and the planning correct, implants may be positioned so that they will be perfectly in the center of the prosthetic crowns. And all of this without distorting our operative habits.
Toltac®precision milling surgery
second advantage of Toltac®system:
With Toltac® the mechanic that guides the rotating instruments isn't in contact with them, therefore the precision of the guide isn't limited by the clearance drill/sleeve. The contact in the guide's rail is much more vertically extended than in the conventional sleeves (2 to 3 times more), thus the angular clearance is extremely reduced and the drills move much more axially.
third advantage of Toltac®system: safer drilling with bone-level drill stop
In the conventional guided surgery the depth is restricted by the contact of the drills with the sleeves, thus due to a wrong template's positioning the drills could work at a depth different than planned and produce damages. Toltac® allows the use of bone-level safety drill's stops (if available in the implant system used) in order to restrict drilling deeper than planned. Otherwise the depth marks on the drill can be easily used in order to carefully check and manage the drilling depth.
limited mouth's opening
The difficult use with limited opening of the mouth is a classical problem for guided surgery, and sometimes for implantology in general.
With the conventional guided surgery the surgeon must climb over the sleeves in order to insert the drills in the planned position.
With Toltac®System the guiding structure is approached by side, as in the freehand surgery, thus there is no need to climb over any sleeves. There is a choice of two different designs of the Toltac® driver's guiding portion in order to allow use with any mouth's opening.
For this reason, Toltac®system is suitable for use in the posterior sites in most cases where the other systems of guided surgery cannot operate.
Obviously, when the mouth's opening is too limited to operate with any kind of drills for implantology, also Toltac®system can't be used.
precision milling surgery
irrigation of the drills
A correct irrigation of the surgical drills is fundamental in order to prevent damages to the bone.
With the conventional guided surgery the sleeve doesn't allow to reach the drill with the irrigating solution, thus the risk of bone's overheating is high.
With Toltac® System there is nothing between the handpiece's irrigator and the surgical drill, thus the irrigation, as desirable, is provided exactly in the same way as in the freehand surgery.
soft tissue's management
With the conventional guided surgery the approach to the operating site often is done with a punch in flapless technique. This is certainly a less invasive technique, but it doesn't allow to manage the soft tissue according the guidelines of periodontology.
In selected cases, also with Toltac® System the flapless technique can be used, but the surgeon can also work as in the freehand surgery with flap technique, thus he can manage the soft tissues as he wishes.
Correct management of soft tissues with Toltac® System
The pollution of the implant site with metal dust by contact of the drills with the sleeves is one of the risks of conventional guided surgery. Since the drilling is guided only after the insertion of the drills in the sleeves, before that moment, drills risk to work not perfectly axially and collect metal dust from the sleeves, with pollution of the implant site. For the same reason, also the guided implants risk metal contamination by touching the sleeves.
With Toltac® System the guiding structure isn't in contact with the rotating drills, thus there is no risk of pollution of the implant site. For the same reason also the guided implants never risk to touch a sleeve.
The conventional guided surgery is always dedicated to particular brands and types of implants, and expensive starter kits of dedicated components must always be purchased in order to use the guided surgery.
Toltac® system can be used with every brand of implant, and needs to use only a single component (the Toltac® driver) and the special Toltac® guides fixed on the templates. There is no need to buy expensive starter kits, because it allows the use of the usual drills for freehand surgery.