After my clinical residency on Sinus Lift Techniques in February, I returned to the Clínica Mayo in Barcelona to observe and work with patients using the latest innovations in Bone Regeneration Techniques, or bone augmentation, in cases of Atrophic Jawbone, i.e. when there is not enough bone to fit implants to the upper or lower jawbone.
Work on the patients was based on 4 Bone Regeneration or Augmentation Techniques:
1. Preservation of the Alveolar Ridge
2. Urban Technique
3. Khoury Technique
4. Alveolar Ridge Split
Preservation of the alveolar ridge. Following the extraction of a tooth or molar, the remaining bone tends to shrink, becoming smaller and narrower when healed. This means that there is less available bone height and width when fitting an implant to replace the extracted piece.
To overcome this problem, bone taken from an artificial source or from the patient themselves is placed in the space left by the extracted tooth. Here we can also use growth factors or fibrin. During the course, we studied a technique consisting of taking a cylinder-shaped piece of bone from the patient’s palate and placing it in the alveolar space at the same time as the implant. This technique is used when the tooth socket does not have sufficient exterior wall.
Urban technique. This technique, also known as the “Sausage Technique”, created by the Hungarian, Dr Urban, is used in the rear part of the jaw, when there is insufficient bone height to fit several implants. It involves vertical bone regeneration.
Here the gum is opened and well separated, leaving a flap to surround the material placed under it in sausage shape. The implants are fitted, leaving two or three threads exposed. These threads are surrounded with bone dust taken with a curved scraper from the area furthest back and to the side of the patient’s jaw, adding a pellet of growth factors with biomaterial.
A long duration membrane is added and tacked in place, just like a tent, where the pegs would be the implants. The next layer is a fibrin membrane, over which the gum is stretched and sewn. The implants must remain in place for 9 months with no load, i.e. without fitting the crowns or using removable dentures to eat. The patient may experience a certain feeling of paraesthesia or tingling for a time. This is a complex and laborious technique which we try to avoid by using very short implants.
Khoury technique. This is a 3D bone regeneration technique created by Dr Khoury from Münster University for cases where we want to augment the height and width of bone at the rear of the jaw in order to fit several implants. A square lamina of bone is taken from the patient, from the exterior of the gonial angle. This lamina, measuring several millimetres , is sagittally divided into two, giving us two square laminas of bone.
These laminas are used to create a formwork for the particulated bone: the two laminas are screwed onto the outside part of the two bone walls of the socket into which we want to place the implants, higher than said walls. Between the laminas, we will place regeneration material, normally a mixture of autogenous bone obtained by scraping the bone, together with biomaterial containing growth factors. After waiting for 6 months to a year, the socket is re-opened, and the implants are fitted. This technique is used in the event of being unable to fit very short implants.
Alveolar ridge split. This is a more common procedure, used above all on the jaw when there is sufficient bone height, but the bone ridge is too narrow to take one or more implants. Having opened the gum, a sagittal incision is made in the bone ridge, with mesial and distal discharges which are neither too long nor too deep. This technique is similar to opening a horizontal bread roll to take one or several vertical hot dogs.
Increasingly wider expanders are gradually placed between the two half-open laminas to create the split to take the implants. Growth factors are used to fill the space between the implants. The external lamina, the one that moves, is connected to the interior lamina, which is held in place, with two screws. The whole area is surrounded with a fibrin membrane containing bone particles obtained by reaming. It is important not to stretch the gum too tightly when sewing. We must then wait for 6 months to a year for completion of the implant osseointegration process.