The ideal distance between Tooth and Implant: How to calculate it in presence of low visibility in complex cases

10 Mar 2018 - 3988

From the literature, we know that in implant surgery, to obtain aesthetic and functional results, a minimum distance of at least 1.5-2.0 mm between implant and natural tooth and of 3.0 mm between implant and implant must be maintained. Failure to comply with these parameters would result in a resorption of the interproximal bone crest with loss of the papilla and consequent aesthetic and biologic damage, as well as problems from a prosthetic point of view.

These rules are fundamental both in simple implant rehabilitations and even more in complex cases, where visibility and spaces are very reduced, and the potential for error is high, both from an aesthetic and a functional, or biologic point of view.

 

Not to make mistakes, it is possible to use the guided surgery technique, with increased costs and time to devote to the study of the case, or it is possible to use the Implant Misura MR which is a very useful tool in every implant cases in order to obtain better aesthetic and biologic results in an easier and predictable way, and becomes a fundamental aid for success in the more complex cases.

This tool helps to easily identify the proper position of the first bur in order to start the bone drilling, thus ensuring a correct final distance between the natural tooth and the implant or between implant and implant, without complex calculations and intra-operative measurements which could be difficult to read by the use of a periodontal probes.

 

In fact, it is really difficult to calculate accurately this distance with a periodontal probe, or even impossible; in particular, in the rehabilitations of the posterior sectors, in patients with reduced mandibular opening, where the visibility is not so good.

To determine the correct distance to which position the first drill, precise calculations are necessary, starting from the diameter size of the implant to be adopted, and, obviously, a good visibility is required in order to insert and view the periodontal probe.

Once the ideal position to start the osteotomy is identified, it is necessary to maintain it during bone drilling, and this exact point is sometimes not so easy visible.

All these difficulties for the correct implant placement become critical in complex cases, with patients with reduced opening, small mouth and reduced bone thickness, in which it is really difficult to maintain stable the first drill in the correct position.

Fig. 1

At the TC-Cone Beam it is visible that in the third quadrant, distal to the canine the patient had previously undergone a horizontal bone regenerative surgery with Bone Lamina Technique, in order to obtain a bone thicknesses suitable for the insertion of implants of adequate diameter. From the radiographic and intraoperative images, it can be seen how the desired bone augmentation has not been obtained completely, consequence of the grafted material partial reabsorption.

Fig. 2

Despite the partial failure of the regenerative surgery, after six months it was decided to proceed with the implants insertion, evaluating it as suitable to receive 2 small diameter implants.

The decision of where to drill the bone in order to correctly position the implants would not have been so easy with the use of a periodontal probe, especially in this case, with a patient with a reduced mouth opening, with significant visibility problems and very thin bone crest. Moreover, it is very difficult to maintain stable and fixed in the correct position the first drill, because with a thin crest the first drill has a lot of problems in maintaining the right position.

The Implant Misura MR instrument in this clinical case ensures greater simplicity in implant placement and greater accuracy, because it offers a rigid and stable wall to which the drill can stay, without any problem of view, and without any problem to calculate the right distance from the root of the adjacent tooth.

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

The instrument must be placed in close contact with the root of the element 3.3 and then it is possible to start drilling being sure to keep the drill with the right 3D direction, and in contact with the instrument, if 2.0 mm is the desired distance of the implant from the tooth.

Fig. 3

The instrument has two sides: the one to distance the implant from the natural root, ensuring 1.5-2.0 mm of space, the other to separate two initial drills to obtain a minimum distance of 3.0 mm between two implants with the same diameters.

Fig. 4

In this situation, the instrument was used to distance the first inserted implant from the initial drill in order to assure a bigger distance from the two implants, so that the prostheses would have a better and more natural appearance.

Fig. 5

The two implants correctly inserted, with the healing screws and the flap sutured.

Fig. 6
Fig. 7

The final post-operative X-ray shows the correct implants position, and the precise distance between them, and the natural tooth.

 

The Implant Misura MR instrument was fundamental to obtain this result, especially in a complex case, with an important bone atrophy, and accessibility problems of the operative field.

Without the measuring instrument, it would have been very complex to insert implants with such precision and simplicity, due to visibility problems, and a narrow crest on which it is very difficult to maintain fixed and stable the first bur in the desired position.

Fig. 8

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

 

Conclusions

For the correct implants insertion, both in simple and complex cases, it is important to maintain a minimum distance of 3.0 mm between implants, and of 1.5-2.0 mm from an adjacent tooth in order to maintain an adequate interproximal bone crest and therefore the possibility to maintain a natural papilla, as well as a prosthesis with harmonic and natural proportion.

This is necessary to ensure to the patient an optimal functional and aesthetic results.

In simple cases, but even more 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 of complex calculations and that can be exploited in complete safety even in reduced visibility sites, ensuring correct insertion of the implant maintaining all the minimum distances required.

Bibliography

  1. Saadoun AP, LeGall M, Touati B: “Selection and ideal tridimensional implant position for soft tissue aesthetics.” Pract Periodont Aesthet Dent 1999;11(9):1063-107

  2. 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

  3. Tarnow DP, Cho SC, Wallace SS : « The effect of inter-implant distance on the height of inter-implant bone crest » J Periodontol 2000;71:546-549

  4. 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

  5. Grunder U, Gracis S, Capelli M: “Influence of the 3-D bone-to- implant relationship on esthetics.” Int J Periodont Rest Dent 2005;25(2):113-9