Bone grafting is part of the Regenerative Dentistry procedures and it is aimed at restoration/regeneration of bone tissue that was lost as a result of either trauma, disease, atrophy or combination thereof. As was described here, titanium or other bone compatible implants should be placed/submerged into a bone tissue and preferably the one with a good density, because only bone tissue will respond with biological “integration” to those implants. Whenever the bone is not present or has insufficient dimensions or density then the bone grafting and compaction is necessary. In other words, the bone grafting procedure can be described as bone contour augmentation using either transplanted bone or bone like bio-compatible substances.
Once the natural tooth is lost then the bone that used to hold it undergoes a very rapid restructuring. The loss of function that is very often combined with dental infection leads to a bone modification resulting in decrease in volume in a three dimensional pattern. In other words, once the functional load has been lost, your jaw bone does not restore its original configuration since it “thinks” such configuration is no longer needed. The most advance bone loss is usually observed when the tooth or teeth have been absent for longer periods of time. Presence of complete or partial dentures only makes it worse. The latter one acts as biological bone “erasers” due to unnatural support they receive that is being derived from the soft tissue of the gums and which in turn leads to lesser stability.
Another factor that is very specific only for upper posterior teeth is the presence of a large air filled cavities such as our maxillary sinuses. Those sinuses are abundant in our facial structures, and almost every bone in our facial skeleton has it. Their function and biological importance is not fully understood. The large sinuses that are adjacent to upper back teeth are called maxillary sinuses and those are the ones we know that may get infected or get affected by allergies. The upper back teeth act as a “biological support” of the floor of those sinuses and when those teeth are lost for whatever reason the sinus “floor” extends downward. On the x-rays, it looks as if that sinus floor dropped down if we compare it to the areas where natural teeth are still hanging on. Such an expansion of the sinus floor takes place at the expense of the bone tissue that ceases to exist at the area of a drop. In upper toothless jaws, it is not uncommon to see the sinus expansion being so advanced that the remaining bone between the oral cavity and the sinuses becomes paper thin. This is when once again the grafting of the bone becomes an option to restore bone mass and later successfully place implants
To get even more info on bone grafting see our FAQ section.