• Teeth
  • Reconstruction under anaesthesia
  • Implants
    • Sinus inlay
    • Jaw ridge augmentation
  • Veneers/Lumineers
  • Clenching
  • Cysts
  • Dental hygiene
  • Wisdom teeth
  • Power-bleaching

Augmentation of the jaw ridge through calvarial bone transplantation

Under treatment

Patient with receding upper jaw and loss of teeth in the distal upper jaw on both sides.

Under treatment

Condition after advancement of the upper jaw to a normal position on the lower jaw with simultaneous inner (sinus inlay) and outer enhancement of the ridge.

Under treatment

Under treatment

Under treatment

Under treatment

The x-ray shows the condition one year after setting the 8 implants in an optimum position.

For extended ridge structures and sinus inlays the patient's own bone is used in most cases, these days, mostly from the iliac crest. But for larger jaw reconstructions the calvarial bone is far superior to the iliac crest. For smaller ridge augmentations and sinus inlays on the other hand, the patient's own bone can be used from the vicinity of the region of operation, e. g. from the cheek bone, chin or from the ascending ramus of the lower jaw, and occasionally mixed commercially received bovine bone.

Everyone knows that an implant should always be placed only in places where the jaw ridge is adequately broad and high. For pre-implantological ridge constructions, various possibilities are available, such as the guided tissue regeneration with special membranes. Often, however, bone that is additionally shielded by a membrane is used.

The sinus inlay or sinus membrane elevation technique respectively that is often necessary in the lateral region of the upper jaw is an indirect augmentation of the ridge or pseudo-augmentation of the ridge, since the ridge is actually not increased in height, but bone or bone like material is deposited on the maxillary sinus floor after carefully lifting the thin periosteal and mucous layers. Prof. Sailer's intervention is usually done with a piezo-device that can cut through the bone with ultrasound. This gentle procedure brings maximum safety for the necessary preservation of the mucous membrane in the maxillary sinus. Here, it is always necessary to differentiate between a mini-elevation and an extended one.

Bone substitutes

In the case of mini-elevations and mini-reconstructions spanning the region of one or two teeth, bone substitutes are used with a high rate of success, such as cattle bone derivatives or coral material. Unfortunately, these bone substitutes are not bone inductive, i. e. they do not contribute to the growth of bone from their side. Ideally, the bone substitute should be bone inducing, i. e. it should produce bone. If this is not the case it gets replaced gradually by bone. And this takes place only in sections where the capillary flow is favourable, i. e. in the region close to the bony ridge and in the vicinity of the mucous membrane of the sinus, whereas in the intervening sections the bone substitute remains unchanged within the connective tissue.

Patient's own bone tissue

For extended ridge augmentations in cases of advanced atrophy (Cawood, Class IV to VI ) the patient's own bone has to be used almost always. In the beginning stages of pre-prosthetic surgery, the patient's own bone (autologous tissue) taken from the ribs was used often for jaw ridge augmentations. Today, this method is considered to be obsolete, because the bone resorption proceeds rapidly in this case. The most frequently used autologous bone material is the bone material from the iliac crest, which has a totally different structure from the bone in the jaws. Its marrow gets resorbed very fast, the corticalis to a far lesser extent.

Bone building proteins

The formation of new bone at the host place depends on a whole lot of other factors, including the presence of bone producing proteins (Bone Morphogenetic Proteins, BMP), which are found particularly in the hard corticalis and to a lesser extent in the bone marrow. The harder the bone, the thicker the corticalis, and the greater the quantity of BMP the transplant contains, which in turn means that the resorption of the transplanted bone is much lesser.
It is known that soft osteoporotic bones in the elderly can be resorbed very quickly, so that despite the augmentation of bone, no implants can be placed, since the bone gets strongly resorbed within just four to six months.

Bone from the iliac crest and its disadvantages

Whereas the bone from the ribs is no longer used for jaw reconstructions, the most frequently used source of donor bone tissue still remains the iliac crest. Besides the bone resorption levels that cannot be predicted accurately, taking the bone tissue from the iliac crest has a particular disadvantage, namely, severe pain over an extended period, and this even if little bone tissue is removed, such as two square centimetres of bone.
In the case of extensive jaw reconstructions, however, requiring about 6x3 centimetres of bone per jaw, especially if both the circular augmentation of the ridges in the upper jaw and a sinus inlay also need to be done.
Removing bone from the iliac crest region leads to severe pain during movement, which could last for weeks or months and could be extremely unpleasant for patients who are sportive or those who need to climb stairs. Apart from the pain, the incidence of complications at the site of removal, such as those mentioned in the scientific literature, is relatively high. Bone should not be removed from the iliac crest region under any circumstance from patients with hip or knee transplants or those who will need them!

Advantages of using bone from the cranial (calvarial) roof

The bone from the cranial roof area is clearly superior to the bone from the iliac crest. Only the outer bone lamella is used here. The advantages of using the patient's own bone are many:

1. Like the jawbone, the bone is of so-called membranous origin, unlike all other bone materials outside the skull area, which come into existence through an intermediate cartilaginous stage and are formed into the jaw bone locally under bigger resorption.
2. The bone of the cranial roof is extremely hard and consists almost exclusively of corticalis, so that it is decomposed only very slowly. In the case of an implantation, hardly any resorption is seen four to six months later. In the case of delayed setting of implants after ten to twelve months, implantation is always possible, which is rarely the case with bone taken from the iliac crest region.
3. Another major advantage is that the patient will not feel any pain after the intervention and can move about free from pain after the operation. This is especially important for elderly patients, who can only be mobilised with difficulty after extracting bone from the hip region and therefore remain hospitalised for longer periods. The scar will not be visible under normal hair cover.

Disadvantages of using the bone from the cranial (calvarial) roof

The disadvantage of using the bone form cranial roof is that it leaves behind a fine scar that lies within the hair, which is visible in the case of balding men. During the operation the hair is not removed; even the hair in the region where the section is performed is not removed, as in the case of the facelift.
If large quantities of bone are removed from the iliac crest, for instance, it almost always leaves behind a clearly visible scar and often leads to a deformation of the edge of the iliac crest, which could be very disturbing especially in women (who wear bikinis).

Active reformation of new bone

For increasing the height and width of the jaw, the bone from the cranial roof can be overlaid in several layers and fixed using mini-screws made of titanium or resorbable screws fixed to the remaining part of the jaw. For large sinus elevation surgeries, where up to half the entire jaw cavity is filled, the bone from the cranial roof is broken down into chips.
The bony window in the fossa canina is nowadays covered with a special membrane of the third generation, which is not only resorbable and hardens just a few minutes after it is positioned, but is bone inductive at the same time, i. e. the formation of new bone is promoted actively. This happens thanks to N-Methyl-2-pyrrolidon (NMP).
Experiments on animals have shown that the formation of new bone is even superior to that of BMP. We use the same membrane in critical load areas, e. g. in places where two bone transplants adjoin to promote the bony consolidation and avoid the fast ingrowth of connective tissue. In the same manner, we use these membranes in cases where we have removed bicortical bone for smaller augmentations in the chin region and need to anticipate complete ossification at the place of bone removal, e. g. with regard to a subsequent placement of implants, in the interforaminal region.

Proven success

Of the more than 100 extensive jaw ridge augmentations conducted so far, mostly in combination with sinus inlays, we have seen a significant resorption of the cranial roof bone in only one case. Still, the placement of dental implants in the planned positions was possible.
It must also be mentioned, further, that the bone from the cranial roof can be used even if there is advanced osteoporosis of the skeletal system. Bone from the cranial roof, which is known to be membranous in origin, appears to be far less prone to osteoporosis than bone of cartilaginous origin from other parts of the skeletal system like the hip bone (iliac crest bone).

It is known that smoking not only leads to disruptions in the healing of wounds in the skin and mucous membranes (dehiscence) and could lead to the loss of bone transplants, but also a lower healing rate of dental implants.