Bone Augmentation - Quality and Quantity of the Jawbone

Watch Dental Video about Bone Augmentation

Both the quality and the quantity of existing jawbone material are crucial for a successful implantation.

However, in many cases, there is not enough bone material for optimal support of artificial dental roots due to periodontitis, accidents, or other diseases. Today, there are many surgical techniques available to augment jawbones. For example, one can use endogenous bone, cultivated bone tissue, or a bone spreading procedure called distraction. Human bone heals best, while synthetic materials heal worst. When using human bone, it’s possible to use cleaned donor bone or one’s own bone.

However, when using one’s own bone, the transplanted block should not exceed a certain size; otherwise, the majority of the transplanted bone will recede again. The reason for this is as follows: The transplanted bone block contains different cells. The moment the block is extracted, the cells contained in it are cut off from their nutrient supply. In cases of small block transplantation, the new environment quickly supplies the cells with nutrients due to diffusion.

However, if the bone block is too large, diffusion is not sufficient enough to reach the innermost cells in the bone block. Furthermore, it takes several days for new blood vessels to grow into the interior of the bone block. For the cells in the interior of the block, this process takes too long; therefore, due to a lack of nutrients, the cells inside the block die off.

As soon as new blood vessels have grown in the transplanted bone block, the dead cells are broken down by immune cells, which are part of the new blood vessels. An immune reaction then occurs. Unfortunately, in doing so, the immune system doesn’t just remove dead cells, but the transplanted bone as well.

This is why larger bone blocks are transplanted in a microvascular fashion. This means that the bone is extracted with the overlying muscle and the supplying vessel; this vessel is linked to another vessel at the spot where transplantation occurs. This guarantees nutrient supply to the inside the bone block; no cells die off and the bone block does not lose its size.

Microvascular transplantation is not necessary in dental surgeries; as a rule, small bone blocks are sufficient, or one can use cleaned donor bone, which doesn’t trigger any immune response. In large tumor extractions, the microvascular technique should be employed.

Onlay Plastic

Onlay Plastic

Now you might understand why it’s nonsense to colonize cleaned bone structures (i.e., synthetic ones, but also non-synthetic ones) with endogenous cells in the lab. The reasoning for this procedure is that it shortens the duration of the process. However, because of the reasons described above, this makes no sense at all, because the very moment that the bone is extracted from its “optimal” incubation chamber – i.e., the test tube – and implanted into the human being, the cells in the interior of the bone block begin to die off. This happens during the first couple of days after the transplantation, as the bone block “melts away” due to a lack of nutrient supply.

Although this method sounds very interesting and promising, it’s expensive and it isn’t a useful option. Unfortunately, however, this technique is pursued with a lot of energy and money in many hospitals due to ignorance regarding molecular biology. This is all pointless! Another problem concerning bone augmentation is patients who still have some of their teeth or who are experiencing horizontal bone loss (for example, patients with periodontitis). For the bone to grow in, blood is required.

Imagine a vertical bone pocket (vertical meaning that the bone is missing to a very limited degree; for example, only at one tooth as shown in this animation). The bone defect consists of five sides, four of which are bone, and all of which are well-supplied with blood and ideal for the growing in of bone substitute material.

One side, namely the one where the dental root is located, is not supplied with blood – that’s bad for the bone substitute material. Furthermore, this area is an ideal entry site for bacteria, scraps of food, and saliva, because the gingiva does not seal this area well after surgery. All of this impairs bone healing after surgery. In some cases, such isolated defects may be treated successfully with today’s techniques, but if the bone has receded across the entire jaw – i.e., horizontally and not vertically – then no treatment is possible because the sides of the bone that are well-supplied with blood are missing.

This is why the remaining teeth and the dental objective must be taken into consideration before proceeding with any kind of bone augmentation. You can find individual videos about various surgical techniques by entering the respective search words such as, for example:

Alternatives to bone augmentation surgery include deciding against artificial teeth mounted on implants or having a partial prosthesis and/or a full prosthesis made.

The risks of surgery are negligible when performed by an experienced surgeon; nevertheless, complications may occur in individual cases, possibly requiring additional measures. Every additional measure may in turn lead to complications that may be life-threatening in the course of treatment. At this point, we will only discuss the complications specifically encountered in bone augmentation procedures. These are, for example:

  • A risk of disease transmission when using foreign material (depending on how the material has been processed)
  • The material not growing in
  • Bone infections – osteomyelitis
  • Damage to surrounding structures such as the tongue, cheek, nerves, blood vessels, neighboring teeth, and neighboring roots, as well as any corresponding consequences

Luckily, such complications have become very rare due to the combination of positive developments in medicine in the last few decades and precise surgical preparation.

Click here to see the video: Augmentation

 

This post is also available in: German

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