The easy way to implant placement – How to manage distance

5 Oct 2018 - 10400

In implant surgery, a correct implant insertion is fundamental in order to obtain optimal aesthetic and functional results that can be maintained over time.

Incorrect positioning of the implants, with regard to the minimum distances from a natural tooth or another implant, would involve a resorption of the interproximal bone crest with loss of the papilla and consequent aesthetic damage, as well as problems from a prosthetic point of view, not guaranteeing the possibility of using crowns of an ideal shape.

According to the international literature, the minimum distance between an implant and natural tooth should be at least 1.5-2mm, and between implant and implant should be at least 3mm, in order to obtain an esthetic and functional result lasting in time.

 

Normally, a wax-up and a surgical guide are used to insert implants in complex cases, but if these are missing, the most common way to measure the distance from the tooth/implant, from which to start to drill the bone, is the use of a conventional periodontal probe, but this procedure is really inaccurate and difficult, if not impossible in some cases, and it entails a waste of intraoperative time. 

The use of the periodontal probe requires precise calculations, which should take into account the size of the implant to be inserted, the size of the first drill, and the distance that this should have from the neighboring tooth/implant, and obviously a good visibility is necessary to be able to read the measurement on the periodontal probe.

The possibility of reading the measurement from the periodontal probe will depend on the patient’s mouth opening and on the position of the edentulous ridge; moreover, this will always be approximate, not very precise, as it would be impossible to calculate the decimal numbers.

Once the ideal position to start the osteotomy has been identified, it is necessary to be maintained during bone perforation and the exact point is sometimes not so easy to see.

All these difficulties for correct implant placement become critical in complex cases, having limited spaces and impassable anatomical limits. The position of the two implants must be as correct as possible, not only from a biological point of view but also from a prosthetic perspective, in order to have an ideal crown position and an optimal aesthetic and functional result.

The most expensive, but also the most precise alternative to inserting implants as accurately as possible is the use of a guided surgery, which guarantees very high levels of precision, appropriate in the very complex cases, or a conventional classic surgical template made by the use of a wax-up.

However, surgical templates, despite the benefits offered, are very expensive and therefore their use is not always justified or better, sometimes, they are missed to be prepared.

An important help in this difficult and fundamental procedure, and a valid alternative to the two options mentioned above, is provided by Implant Misura space bar, a very useful tool in simple cases which enables to obtain better aesthetic and functional results in an easier, predictable and rapid way, and which becomes a fundamental aid for success in the most complex cases.

This tool helps to identify in an easy and intuitive way the proper position of the first bur to start the bone drilling thus ensuring a correct minimum final distance between the natural tooth and the implant or between two implants, without having to perform complex calculations and intraoperative measurements difficult to read by periodontal probes,and without using expensive surgical guides where not fundamental. Moreover, thanks to the possibility to use different instruments size, it is possible to exploit them in order to position different implants diameters at the desired distance, always respecting the biological limits described in the literature.

Fig. 1

Preoperative OPT (1) and intraoral photos (2) of a patient with partial edentulism in the posterior sector of the I quadrant: absence of 1.6 and 1.7 is completely decoronated.

Therefore, it was decided to rehabilitate the area by extracting the element 1.7, inserting an immediate post-extraction implant and a conventional implant in the 1.6.

In this case, the available space is limited by the presence of two teeth, mesial and distal, to the edentulous ridge, enhancing the possibility of error and requiring greater precision of insertion and spacing the implants correctly, in order to respect biological limits and obtain adequate aesthetic and functional results with correctly sized crowns.

Fig. 2

Once the flap is elevated, the decision of where to drill the bone in order to rightly position the implants would not have been so easy with the use of a periodontal probe, especially in this case which was marked by a superior distal surgical site, with reduced visibility and access and the need to position implants in a pre-established space.

The Implant MisuraMRinstrument, in this case, ensures greater simplicity in implant placement and greater accuracy, avoiding the use of a surgical template as it is not essential.

Fig. 3

The first step is to choose the correct implant diameter and then the corresponding IM-MR instrument.

The instrument has two sides: the first one to distance the implant from the natural root, ensuring 1.5-2mm of distance, the second one to separate the two implants from each other, ensuring the 3mm of distance described in the literature.

Fig. 4

The instrument must be placed in close contact with the root of the element 1.5 and then it is possible to start drilling being sure to keep the drill in contact with the instrument if 2.0 mm is the desired minimum distance of the implant from the tooth.

Fig. 5

In the same way, the IM-MR instrument was used to control the distance from where to start the bone perforation for the distal implant, by the use of a pin inserted in the first osteotomy as a reference point.

The insertion of the implants is prosthetically guided; therefore the instrument is used to verify that there is a minimum distance of 3mm between the two implants, which will be inserted in the position defined by the future prosthetic crown.

Fig. 6

The post-operative panoramic X-ray demonstrates the correct positioning of the implants and the precise distance between them.

The IM-MR instrument was fundamental to obtain this result in a quick and simple way, facilitating and speeding up all the surgical procedures, guaranteeing the highest levels of precision. Without the measuring instrument, it would have been extremely complex to insert implants with such precision and simplicity, due to problems of visibility and access.

Fig. 7

Dr. Marco Redemagni and the Styleitaliano team, designed, together with LM, this set of implant spacers. Available with LM local dealer or online store of Smile Line by Styleitaliano webshop.

 

Conclusions

For the correct insertion of implants, both in simple and complex cases, it is important to maintain a minimum distance between implants (3 mm) and between the implant and an adjacent tooth (1.5-2 mm) in order to maintain an adequate interproximal bone crest and therefore the possibility of having a natural papilla, as well as having the possibility of prosthesizing implants with adequate size crowns; all this to guarantee the patient an optimal functional aesthetic result.

In simple cases, but even more so in complex cases, it is a great advantage to have an instrument that allows to distance and stabilize the first drill for bone perforation from the tooth/implant, simply and quickly, without the need for complex calculations, and that can be exploited in complete safety even in sites with reduced visibility, ensuring correct insertion of the system while maintaining all the minimum distances required.

This tool makes the whole procedure much simpler but, at the same time, more precise and faster, thus ensuring optimal aesthetic and functional results without necessarily having to resort to the use of surgical masks if not necessary.

Bibliography

  1.  Salama H, Salama M, Garber D, Adar P: “The interproximal height of bone: a guidepost to predictable aesthetic strategies and soft tissue contours in anterior tooth replacement.” Pract Periodont Aesthet Dent 1998;10(9):1131-1141

  2. Tarnow DP, Cho SC, Wallace SS: « The effect of inter-implant distance on the height of the inter-implant bone crest » J Periodontol 2000;71:546-54

  3.  Cardarapoli G, Wennstr Öm JL, Lekholm U: “Peri-implant bone alterations in relation to inter-unit distances. A 3 year retrospective study.” Clin Oral Impl Res 2003;14:430-436