WHAT IS BONE AUGMENTATION
Bone Graft
In certain implant situations, bone augmentation is necessary when the amount of bone is insufficient or the jaw bone structure is not suitable to securely anchor a dental implant. This is often due to bone shrinkage or bone loss, which can occur as a result of edentulism or dental disease and worsen without proper treatment. Without intervention, the rest of the teeth may also be at risk of serious dental health consequences and further tooth loss.
Experience has shown that a denser jawbone is more suitable for dental implant placement than a thin, porous bone. Consequently, the higher and thicker the jawbone, the more favorable the conditions for successful implant placement.
Bone augmentation is a surgical method used to increase the thickness and density of the edentulous areas of the upper and lower jaw
When is bone augmentation necessary?
Up until the late 1990s, bone augmentation was only used to improve and stabilize prostheses and prosthesis bearings. However, with the advancement of implantology, it is now almost exclusively used in combination with implant treatment.
There are several reasons for this. Firstly, a sufficient bone volume can be built up to securely anchor a dental implant. Secondly, the implantation of bone replacement material can stimulate natural bone growth and counteract bone loss, which also has a positive effect on neighboring teeth and dental health, as it reduces the risk of further tooth loss.
When natural teeth are lost, for example, due to an accident, bone loss occurs over time due to the lack of stress. Similarly to muscles that are not exercised, the jawbone also shrinks when not in use. Dental implants put a physiological load on the jawbone again, stimulating it in a similar way to your teeth and thus preventing the jawbone from deteriorating.
The implantation is difficult if the jawbone is less than 5mm wide and less than 8-10mm high, as the dental implant cannot be given enough support. The thicker and higher the jawbone, the better the conditions for the successful insertion of dental implants. Depending on the remaining thickness of the jawbone, an individual procedure for jaw reconstruction is selected.
What are the reasons for bone loss?
Bone augmentation may be necessary for a variety of reasons, such as inflammation of the periodontium (periodontitis) that causes the jawbone to break down, or teeth that have been pulled or lost. It is also possible that the jawbone only degrades after implantation due to peri-implantitis, which allows bacterial inflammation to get into the jawbone. In some cases, it is sufficient to expose the implant and remove the inflammation. In other cases, the implant has to be removed and the bone rebuilt to anchor the dental implant firmly in the jaw again.
Anxious patients and elderly patients are particularly prone to bone loss. Anxious patients may delay an early visit to the dentist, missing out on timely treatment. Elderly patients may already have dentures, which can cause the underlying jawbone to degrade due to the unnatural pressure load. The lower jaw is usually more affected by bone loss than the upper jaw due to the disproportionate pressure distribution.
Which Materials are used?
Modern dentistry offers a wide range of options for replacing the natural jawbone. Depending on the degree of bone loss and the practitioner's criteria and preferences, different bone replacement materials can be used.
These materials include the patient's own bone matter, as well as very biocompatible bone substitutes materials such as human tissue, animal tissue, or synthetic graft material. All of these materials are well accepted by the body.
In addition, there are special techniques such as bone splitting and bone spreading which can be used to build up bone without having to use replacement material directly. These techniques require experienced handling.
Which treatment methods are used for bone formation?
The choice of the appropriate treatment method for bone augmentation in the jaw depends primarily on the type of bone deficit. The jawbone can be too narrow or too low for one treatment method, which is why another method has to be chosen. It also depends on where in the mouth (upper jaw, lower jaw, front or side teeth) the lack of bone mass is located. Due to the different structures of the bones, some special features must be observed, for example, with implants in the upper jaw and implants in the lower jaw.
Especially in the posterior region, the bone supply is usually unfavorable for implantation and because the maxillary sinus takes up so much space in the upper jaw, bone augmentation in the upper jaw is necessary in many cases. Frequently used techniques and methods for bone augmentation are, for example:
- sinus lift
- nasal floor elevation
- Socket Preservation
- trapdoor technology
- Bone Spreading and Bone Splitting (jaw bone widening)
- Distraction osteogenesis (jaw bone elevation)
- Overlay osteoplasty using autologous bone (jaw ridge augmentation)
Once all preliminary examinations have been carried out, the advantages and disadvantages of the respective method for the patient have been weighed up and the planning has been completed by the dentist, a decision must also be made as to whether immediate or delayed implantation should take place. This decision depends, among other things, on jaw conditions and surgical aspects.
What are the risks of bone augmentation?
In general, bone augmentation carries only a few risks, which are also very low. It is generally well tolerated, with symptoms similar to those of tooth extraction. However, a small residual risk of complications cannot be ruled out, so the same risks exist as with any other medical intervention
Possible complications include:
- infections
- inflammation
- Wound healing disorders
- Rejection of the bone substitute material
The probability of the bone replacement material not integrating properly and needing to be removed is very low. Taking antibiotics after the augmentation can help prevent these residual risks.
Under certain circumstances, the membrane separating the nasal and maxillary sinuses or the lower jaw and tongue nerves may be injured during the procedure. If the membrane is breached, it can be treated directly. If the nerve is injured, temporary numbness in the lower or upper lip may occur, though this is very rarely permanent.
How long does it take to heal after bone grafting?
On average, the procedure for bone formation takes 1-2 hours, but patients must be patient with the healing time. For the implant to be inserted, the bone formation must be successful. This process can take 3-6 months for the bone to gain the necessary strength. After the implant is inserted, a few months of rest and healing are needed before the jaw can be fully loaded again.
For minor bone defects, the bone structure and implant insertion can be done in one operation. This shortens the total healing time compared to multiple procedures.
What alternatives are there to bone grafting?
As a conservative alternative to bone augmentation without dental implants, classic forms of dentures such as dental bridges, crowns, and prostheses can be used. Depending on the initial situation (missing single tooth, residual dentition, free-end situation, or complete edentulism), it must be weighed up which form of denture comes closest to the remaining healthy teeth.
Conventional bridges, for example, require at least two healthy and caries-free teeth to be ground down, resulting in an irreparable loss of substance. Compared to conservative dentures, the use of dental implants offers greater comfort and prevents bone loss and incorrect loading of the other natural teeth.
If you do not want to resort to removable dentures, but would like to gain more quality of life through the wearing comfort and safety of dental implants, there are implants, especially for the upper jaw (so-called zygomatic implants), which, due to their length and positioning, can be used with and despite existing bone loss in the upper jaw. Another implant-supported alternative to bone augmentation is the All-on-4® concept, in which a prosthesis is anchored to 4, 6, or 8 implants per jaw using a bar construction. In some cases, the concept also works with 2 implants.