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| IMC Wiki | Condensation techniques

Condensation techniques

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Introduction

Sufficient quality and quantity of the local bone is one of the key factors in implantology. Primary stable implant insertion is difficult with large amounts of cancellous bone.
With the osteotome technique, the cancellous bone is consolidated laterally, or pushed back cranially towards the antrum.
The osteotome technique was described by Summers in 1994. He attempted to increase the primary stability by using the bone condensation technique in the posterior maxilla.
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Primary stability

The primary stability of an implant is mainly dependant on two factors: Firstly, on the surface of the implant (structure, material, size), and secondly on the quality and the quantity of the surrounding bone.
The effects of lower bone density are more important for the bones around the implant than the lower bone height (Meyer et al. 2001).

With progressive bone atrophy, the cancellous character of the maxillary alveolar process becomes more apparent. The area of the tuberosity shows a highly characteristic cancellous bone structure.
The high levels of cancellous bone make the primary stability for the implant insertion more difficult (Misch 1990 b).
Therefore, the remaining alveolar process is of the poorest quality in the area of the strongest occlusal force. Furthermore, the necessary implantation depth is limited by the caudal limitation of the antrum.
To improve bone density on site, the bone is not removed when the implant bed is prepared with bone condensation but is compressed laterally and/or apically.
In a histological and histomorphometrical analysis of implant osseointegration, Nkenke et al. (2002) showed a use of the osteotome technique in relation to an increased bone implant contact in the early phase after implant insertion.

This results in a zone of traumatized bone with a variety of chipped trabeculae but also intact osteocytes.
The primary stability is improved when the term 'primary stability' is taken to mean that a tactile movement is not present.

However, if primary stability means stability of the implant for immediate loading, the studies on implant stability at different points in time after different preliminary treatment of the bony bed resulted in the following:
The mechanical stability (twist-out attempts as well as resonance frequency measurements) was significantly firmer with the conventional preparation technique (guide drilling) than with bone condensation.
Increased osseointegration after bone condensation could also not be proved.
The preparation of the implant base with bone condensers causes micro-fractures that lead to a significant reduction of the biomechanical primary stability.

The highest primary stability with enossal implants can be reached by simply drilling the implant base; the additional tap reduces the primary stability. The application of bone condensers significantly reduces the primary stability (Büchter et al. 2003, Büchter et al. 2005).

The results of this study are of clinical importance for understanding the early osseointegration processes in condensed bone. The reduction of the mechanical properties has a more pronounced effect on implant stability than gaining peri-implant bone. Therefore, bone alone cannot determine the mechanical stability of the peri-implant bone.

Recommendation

The bone condensation method is a good technique to avoid more significant augmentation procedures for smaller bone deficiencies.
However, if the implant is to be loaded soon or immediately, it should be inserted in the conventional manner with a drill. (Büchter et al. 2003, Büchter et al. 2005).

Indication

Non-ablative osteotome technique according to Summers is suitable for use in the maxilla.
  • Spreading and stretching a narrow alveolar process
    If the alveolar process is not wide enough, the osteotome technique is used to widen the bone vestibularly. This requires cancellous bone between the outer and inner cortical bone.
  • Performing an internal sinus lift
    When the height of the local bone is at least 6-7 mm, then the floor of the antrum can be lifted by l-3 mm.

Instruments

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Conical elevators cause mainly lateral condensation, cylinder-shaped elevators cause a vertically aligned condensation.

Procedure/therapy

Lateral bone condensation

Insert osteotomes with increasing diameters until the implant diameter is reached. This laterally compresses the cancellous bone.
Cancellous bone is easy to compress at first.
However, the more bone is compressed around the osteotome, the more difficult it becomes to push still more bone aside and compress it.

Bone spreading and stretching

With bone spreading and simultaneous bone condensing, the alveolar bone can be prepared in many cases without extensive inlay and/or onlay grafts.
The vestibular wall is stretched outwards when the alveolar process is not wide enough.
When a pointed alveolar crest is prepared with conventional drilling techniques, this often results in a perforation of the vestibular bone wall.

First, place an incision with the osteotomy disk in the horizontally resorbed jaw segment. Then insert the instruments to sufficient depth.
Twist in the spreaders slowly and in a controlled manner to give the bone time to extend. Expand and vestibularly stretch the bone cavity to the desired diameter.
Then use a standard drill to prepare the implant bed.

In a jaw with an extremely pointed alveolar crest on which the outer and inner cortical bone do not encompass any more cancellous bone, bone spreading is contra-indicated but onlay or inlay grafts may be used.

Internal sinus lift

Vertical condensation increases the amount of available bone in the area of the floor of the antrum.

After the incision and flap mobilization, drill 3 mm deep with a hollow burr.
This eases the mobilization to the antrum. The calibrated instruments are used with increasing diameter and inserted by light tapping.
The basal surface of the work side is concave and has sharp edges.
When used, this geometry pushes the bone column cranially.
The antral mucosa is lifted and the resulting space is filled with bone.
As soon as the working end has reached the floor of the antrum, less strength is required since the bone column is no longer pushed forward.
There is only circular bone compression.
This method can also be used to deliver autologous bone caudally from the floor of the antrum.

Complications

  • Fracture of the vestibular bone lamella
    If this risk is to be minimized, it is helpful to leave the periosteum on the bone and to prepare a mucosal flap on both sides. This results in a periosteally pedicled fracture segment which heals without additional problems.
  • Rupture of the antral mucosa


sources

  • Büchter A, Kleinheinz J, Joos U, Meyer U (2003)   Primary implant stability with different bone surgery techniques. An in vitro study of the mandible of the minipig   Mund Kiefer Gesichtschir 7:351-5 Epub 2003 Oct 24
  • Büchter A, Kleinheinz J, Wiesmann HP, Kersken J, Nienkemper M, Weyhrother H, Joos U, Meyer U (2005) Biological and biomechanical evaluation of bone remodelling and implant stability after using an osteotome technique. Clin Oral Implants Res 16:1-8
  • Meyer U, Vollmer D, Runte C, Bourauel C, Joos U (2001)   Bone loading pattern around implants in average and atrophic edentulous maxillae: a finite-element analysis   J Craniomaxillofac Surg. 2001 Apr;29(2):100-5
  • Misch C (1990)   Classifications and treatment options of the completely edentulous arch in implant dentistry   Dent Today. 1990 Oct;9(8):26, 28-30
  • Misch CE (1990)   Density of bone: effect on treatment plans, surgical approach, healing, and progressive bone loading   Int J Oral Implantol. 1990;6(2):23-31
  • Nkenke E, Kloss F, Wiltfang J, Schultze-Mosgau S, Radespiel-Troger M, Loos K, Neukam FW (2002) Histomorphometric and fluorescence microscopic analysis of bone remodelling after installation of implants using an osteotome technique. Clin Oral Implants Res 13:595-602