What is bone grafting?
The quantity and quality of the jawbones can be influenced by various factors. Certain genetic factors determine the size of the jawbones, including the width and height of the jawbone ridge. An important anatomical factor is the extent of the sinuses, which can reach the area between the roots of the teeth in the premolar and molar regions.
If the height and/or width of the jawbone in the area of the missing tooth or teeth is insufficient for implant placement, a bone grafting procedure is necessary.
Generally speaking, for the safe placement of an implant, approximately 6mm of width and 10mm of height of bone are required. Various bone grafting procedures can increase both the width and height of the bone.
There are numerous bone grafting techniques. Bone can be replaced using the patient’s own bone (e.g., from the area behind the teeth in the lower jaw or, in extreme cases, with a bone block harvested from the hip), synthetic bone graft materials, or inorganic bone matrix derived from cattle.
In addition to the materials used, the techniques for bone grafting also vary widely. The specialist performing the bone grafting decides on the materials and techniques based on the specific anatomical situation.
A 3D CBCT scan is always essential beforehand, as it allows for a clear diagnosis of the available bone structure.
Why does bone deteriorate?
After the removal or loss of teeth, the jawbones are no longer subjected to stress, as the chewing force is no longer transmitted to the bone through the periodontal ligament system. As a result, the signal for bone remodeling ceases, and the bone begins to resorb.
The degree of bone resorption is most significant in the first year, which is why it is crucial not to let too much time pass between tooth removal and implantation.
Otherwise, bone grafting is likely unavoidable if an implant is to be placed to replace the missing tooth.
In certain conditions, bone resorption may begin even before tooth removal. One such condition is periodontal disease.
In periodontal disease, inflammation gradually destroys the bone surrounding the tooth. In more advanced cases, if traditional treatment is unlikely to yield results, it is better to remove the tooth with a hopeless prognosis to prevent further bone resorption.
Not only periodontal disease (parodontitis) but also other conditions, tooth-related inflammations, abscesses, and cysts can lead to various bone defects and deficiencies.
Different traumas, accidents, or tooth extractions performed without sufficient caution can also lead to bone loss if the tooth socket is damaged.
When and why is bone grafting necessary?
Based on a 3D CBCT scan, the amount of bone can be clearly diagnosed. In many cases, there is insufficient bone available for implant placement (both the width and height of the bone influence the implantation).
If the available bone is inadequate, there are numerous routine procedures to create sufficient bone for implants. To accurately assess the quantity and quality of the bone, a specialized dental CT (CBCT) is required.
Bone grafting generally involves creating an environment/framework using various methods and materials where bone formation can begin.
The most common approach is the use of commercially available bone graft materials, which are often of animal origin (cattle, pigs). Additionally, human-derived and synthetic bone grafts are also available.
These bone grafts are always subjected to special procedures to ensure they are completely sterile and pose no risk.
The bone graft material creates the space into which the patient’s own bone tissue can later grow. They are available in various forms and particle sizes, with varying absorption times; synthetic bone grafts typically absorb faster.
For larger bone grafts, some of the patient’s own bone chips are mixed with the graft material. These chips can be collected during the preparation of the implant bed or harvested from the surrounding surgical area using bone scrapers.
The essence of this technique is that the patient’s own bone contains numerous growth factors that promote the bone formation process.
How is bone grafting performed, and how long does it take?
Sinus lift
In the upper jaw, the roots of the teeth are often separated from the base of the sinus by only a few millimeters of bone tissue.
After tooth removal, the amount of this thin bone further decreases.
In cases where the bone height in the upper jaw in the premolar and molar regions is insufficient, the sinus must be lifted to create adequate bone for implant placement.
Internal sinus lift (closed sinus lift)
This surgical procedure is used for minor bone deficiencies. After pre-drilling for the implant, the sinus membrane is lifted through the hole, and bone graft material is placed underneath.
The implant is then placed. There are various methods for detaching and lifting the sinus membrane through the hole.
With a closed sinus lift, typically only 2-3mm of bone height can be gained.
The surgery, including implant placement, takes approximately 1 hour.
External sinus lift (open sinus lift)
This surgical procedure is used to restore larger bone deficiencies. The gum is opened, and a bone window is prepared on the outer wall of the upper jaw.
Through this window, the sinus membrane covering the lower wall of the sinus is carefully lifted.
The space created is filled with bone graft material through the bone window under the sinus membrane, and the bone window is closed with a special membrane or simply with the gum flap.
If the bone height reaches 4-5mm, the sinus lift can be performed simultaneously with implant placement.
If the bone height is less than 4-5mm, the bone grafting and implantation are usually performed in separate sessions. First, the sinus lift is performed, followed by implantation after approximately 6 months of healing.
It is important for the sinus to be healthy. In cases of repeated or chronic sinusitis, sinus lift is contraindicated.
Postoperative symptoms are usually mild, but occasional nosebleeds may occur. In the weeks following surgery, it is strictly forbidden to blow the nose or engage in activities (e.g., lifting heavy objects) that increase pressure in the sinus.
The open sinus lift can be completed in 1-2 hours, depending on the complexity of the case, with a healing time of approximately 6 months.
In addition to sinus lifts, other bone grafting procedures are also distinguished. Generally, their goal is to increase the height or width of the bone, or both, at the planned implant site.
Various techniques are available for this purpose.
Depending on the bone deficiency and the specialist performing the surgery, numerous solutions can be applied.
Jawbone “thickening” (lateral augmentation)
In many cases, the width of the jawbone is insufficient for implant placement.
This can be restored by transplanting the patient’s own bone. The patient’s own bone can be transplanted from within the mouth, typically from the area of the lower wisdom teeth, or in cases of extreme bone deficiency, from the hip bone.
Lateral augmentation can also be performed using commercially available bone grafts and membranes.
These materials are usually of animal (cattle/pig) or human origin, and their use is completely safe. The role of the granular bone graft is to create a special framework along which the bone formation process can begin.
The granular material is typically covered with a special absorbable (or sometimes non-absorbable) membrane.
This type of surgical procedure can also be performed simultaneously with implant placement if the initial bone quantity allows it.
In situations where the bone is extremely deficient, simultaneous implantation is not possible. In such cases, after the bone grafting procedure, a minimum of six months is required for sufficient bone to develop.
When the patient’s own bone is transplanted (usually harvested from the lower jaw in the area of the wisdom teeth or the chin), the healing time can be reduced to 3-4 months.
Will the result be perfect after the treatment?
Generally, the smaller and more localized the bone deficiency, the more predictable the result.
Patients are always appropriately informed about what to expect from a specific bone grafting procedure, including postoperative discomfort, possible complications, and expected outcomes.
Bone grafting procedures always require antibiotic prophylaxis. The first-choice antibiotic is usually amoxicillin, which is replaced with clindamycin in cases of allergy.
The antibiotic should be started immediately before the surgical procedure and continued for one week after the surgery.
After the procedure, facial swelling (edema) is likely to occur, which is usually most pronounced on the second day after surgery and then decreases day by day.
To reduce swelling, it is very important to apply ice externally to the area after surgery.
Occasionally, discoloration of the facial skin may occur due to tissue bruising.
Stitches are typically removed two weeks after the procedure.
After larger bone grafts, since the volume of the bone has been increased, the gum must be “stretched” to close the surgical area. In such cases, a minor gum correction surgery may be recommended near the end of the healing period to ensure the implants are surrounded by firm gum.
The presence of firm gum is crucial for the long-term survival of implants.
In what cases is bone grafting not possible?
If someone has undergone antiresorptive treatment due to osteoporosis, i.e., received bisphosphonate derivatives intravenously or in tablet form (typically one tablet per week), bone grafting is contraindicated.
These substances alter the bone’s defense mechanisms, which can lead to bone necrosis (osteonecrosis) in the event of bone injury, making most oral surgical procedures contraindicated.
In smokers, failure is much more common because smoking impairs the oxygen supply to the tissues. Patients are generally asked to quit this harmful habit in the weeks leading up to surgery.
Patients are always informed about possible alternatives, whether it involves rehabilitation with implants or the creation of removable prosthetics.