This case shows how to place an implant in a a narrow ridge after several years without teeth, same as case “bone splitting (1)” This patient lost the two premolars, but we will only replace one, a little distally, for a fellow doctor to retrude the cusp with orthodontics, anchored on the implant. The difference is that in this case I will need to use a resorbable membrane.
An abscess is growing since long around the root we need to pull out.
I decide to extract the root and let the abscess cure before placing the implant. It is safer than placing the implant immediately, but there is a counterpart, too.
The exterior cortical layer is normally damaged by an existent bone loss, through which the abscess has being draining. So we could expect great collapse during the healing time. 3-4 months, as it happened in fact.
The two corticals have collapsed transversally, leaving a ridge much narrower than what I need to place a 3.2mm standard (hollow) where to screw abutments for the ortho treatment as a well as the final prosthesis.
We can’t do any drilling here. It would remove the little spongeus bone left in between the two inner and outer corticals. The first approach is to make a puncture and try to expand it. This gives me an idea of bone density and elasticity. The more spongeus there is, the more malleable the bone is.
This bone doesn’t accept further expansion, it doesn’t flex. So I need to split the bone. I use a radial mini-saw to open the ridge and a set of chisels to enlarge the opening.
Then, I use more expanders until I reach the necessary width to insert the thinnest implant available
Note that the direction may not always be the best. The concavity of the external bone may cause the direction of the implant to be not straightly vertical, as it would provoke exposition of the end part of the implant.
But in this case the axis is almost vertical and the bone can be split to insert a 3.75mm regular implant. The outer cortical shows a deep crack. You have to be careful to expand but not to break the cortical. We want to gain bone, but not to lose it. If we cannot expand wide enough as to insert the implant in that surgery, we may need to fill the gap with bone graft and cover it with a membrane. Wait a 3-4 months and then repeat the operation.
The collagen membrane, Bio-Guide, is cut to fit in place and perforated to let the healing screw enter the inner thread of the implant
I always start fixing the membrane from the far end, while filling the vestibule with graft (Bio-Oss). Stitches are applied to close the flap in place.
Stitches should be kept as long as possible, since the has been a considerable increase in volume that makes complete closure difficult.
A tetracycline gel can be used to prevent infection. Tetracycline is preferred over hexetidines because these have been reviewed to affect the collagen regeneration the area.