The restoration of a lost bone

 
In this section I want to talk about such a complex and unsolved topic, as the restoration of a lost bone.
The loss of alveolar bone (bone plate that surrounds the tooth root and remains after the extraction) is associated with a disease or tooth loss, and may occur as a result of trauma, as well as to be associated with resection (excision of the bone) interventions aimed to eliminate pathological entities ( For example, cysts).
 
Lack of bone is a major challenge that we face during implantation. During the first year after tooth extraction a fast irreversible atrophy of the alveolar bone happens. In addition, bone loss often occurs as a result of periodontitis, which leads to the formation of large bone defects. 
 
Bone loss (atrophy) can occur in height, thickness, and height and thickness at the same time. To restore the lost bone various bone materials or their substitutes are used. In making the bone material in the area of atrophy new bone is formed by one of the mechanisms:
1. Osteogenesis (submitted material contains cells that make up your bone).
2. Osteoconduction (the material can serve as a scaffold for developing of the bone)
3. Osteoinduction (material contains substances that stimulate bone growth).
 
There are following types of bone material or substitutes for restoration of a lost bone:
1. Autogenic graft - materials that are transplanted from one body part to another in one person (e.g., for lack of bone in the front sections of the upper jaw the bone is taken from the angle of the mandible in the same person). This type of transplant is considered to be the most assured, as autotransplants contain viable cells and affect the formation of new bone by osteogenesis, osteoconduction and osteoinduction.
2. Allogeneic bone materials are made from human cadaveric bone through removal of living cells and freeze-dried mineralized bone. Such material has osteoconductive and osteoinductive properties. If combining with autologous bone you can also get a guaranteed result.
3. Xenogeneic bone materials of bovine origin, material, possessing osteoconductive and possibly osteoinductive properties. Give excellent results for uncomprehensive defects.
4. Alloplastics - synthetic or inorganic materials that can be used as substitutes for bone. Have only osteoconductive properties. This material is considered to be the least predictable and when it is being used the result cannot be guaranteed.
 
Using different types of materials and a variety of surgical techniques the alveolar bone may be increased to the extent necessary for the implant.
 
So, what are the basic surgical techniques for restoration of a lost bone:
1. Sinuslifting or subantral augmentation – lifting of the lower wall of the maxillary sinus.
After tooth extraction in the lateral parts of the upper jaw, we face the deficit of bone height due to the low-lying maxillary sinus. In these cases, use an indoor sinus lift (if necessary to raise the bone for 1-2 mm through a hole drilled for the implant) or open - when, with a large deficit of bone in the front wall of the upper jaw a window is done, and through it the sinus membrane is raised and the resulting cavity is filled with one of the bone materials.
 
Open sinuslifting 
 
Closed sinuslifting
 
With a large shortage of bone must necessarily use autologous transplant with allogeneic or xenogeneic materials.
 
2. Restoration of a lost bone with blocks
When installing the implant, the bone thickness should be not less than 7 mm. After teeth removal the alveolar bone is atrophying (thinning)during the first year, and often it doesn’t have the thickness of 7mm. For restoring the lost volume from the corner of the lower jaw or chin area a part of bone (bone box) is taken, which is fixed to the missing parts of alveolar bone. The donor site heals quickly, and in the accepting part of the alveolar bone the necessary for us depth for future implant placement is formed guaranteed. With small defects, allo-xenogeneic materials are used instead of autotransplants.
The restoration of a lost boneThe restoration of a lost bone
 
3. Splitting of alveolar bone.
If the alveolar bone has a thickness of more than 4mm, and less than 7mm, the volume is increased by splitting it into two parts, with simultaneous installation of implants and completion of the resulting gap with bone materials.
 
4. Segmental osteotomy
The surgical technique which allows to increase the alveolar bone height. A partial separation of the alveolar crest into two parts with a piezosurgical tool is made. The moving part is lifted, fixed with special plates for asteosynthesis to the fixed part and the resulting gap is filled with bone material.
 
5. Distraction osteogenesis.
The method is similar to the previous one, but differs in that instead of plates for osteosynthesis a special distractor is used, which is fixed to the patient’s jaw for a few months and the patient self-activates it daily, gradually increasing the bone height.
 
There are many versions of the five basic methods. The choice of method depends on the degree of atrophy (decrease) remaining after the loss of teeth of the alveolar ridge and the patient's willingness to meet the increase of the lost bone to obtain further long-term aesthetic and functional result.
 
Do not install the implants without having a proper amount of bone tissue as this would lead to their short lifetime and questionable aesthetic result.
 
Recommendations:
1. If, after passing computer tomography a deficiency of alveolar bone is seen at the site of the planned implantation, it is necessary to make the restoration of the lost bone.
2. Go to a professional who specializes in bone transplantation.
3. For your comfort I recommend doing drug sedation (sleep during surgery) for any of these techniques.
4. In the day of surgery you have to come with your attendant.
5. After surgery there will be an after surgery swelling for a few days. I recommend sticking to home treatment within 3-5 days.
6. On the intervention eve you need to buy all the medicines prescribed by the doctor.
7. Carry out all the recommendations in the postoperative period and regularly attend the examination.