This case shows the placement of two individual implants, each with different characteristics.
The upper one must be placed in the 15 bicuspid area. The bone has collapsed during resorption, although, externally, it doesn’t seem so.
The lower one must substitute a damaged 46 molar,which presents periapical abscess in both rots, bone loss in the septum and fistula draining to vestibule.
I start always by the easier part of each surgery. Which, in this case, is the upper implant.
After opening the flap I find a concave vestibular bone, with a ridge of about 4”, insufficient for placing a 3,75” with safety margin ridge bone on either side of the implant.
A smaller diameter implant could have been used, but this is a heavy duty area for chewing, and for me, the wider and longer the implant is, the better.
So, I expand the ridge to the limit of its elasticity in the desired angle. Again, I could have chosen another angle for insertion, but the more vertical, the better long term expectancy, especially in single, heavy loaded implants. You can appreciate the vestibular groove due to the concavity, angle of insertion and elasticity limit.
I place a 4×15” 3i implant and proceed to cover the bone defect with Bio-Oss bone graft and Bio-guide resorbable collagen membrane fixed by the healing screw.
The lower molar, after extraction, leaves a wide crater, wide septum resorption, as expected by x-rays, and a thin, cracked by the extraction, vestibular wall, through which the fistula was draining out.
I prefer to postpone the implant placement for a second phase. By now, I clean the alveolus thoroughly, removing all soft tissue, fill it up with Bio-Oss bone graft and Bio-guide resorbable collagen membrane, and try to close it as much as possible with the flap.
Four months later we check X-rays and see the shadow of the new generating bone in the alveolus.
Ridge preserved in height and width, the placement is now simple.
This case presents severe periodontal disease. The only logical treatment plan is full extractions and new denture.
The bone ridge is very damaged and there too many irregularities as to approach immediate implants after extractions. I prefer having the teeth extracted and wait until the bone ridge is in better, safer shape.
In addition, an impacted upper right cuspid will leave a big hole in the bone in an area that I will need to use for implantation.
So, I proceed to extract the cuspid and fill the bone defect with Bio-Oss graft, covering it with a resorbable Bio-Guide membrane.
Then, all the teeth are extracted by his general dentist, who places a removable denture while waiting for the bone to heal.
Four months later, the bone ridge is more regular
Then, I place six implants on each jaw.
Note the unexpected, deep bone defect that laid after previous extractions of the upper right molars, which was filled up with soft tissue.
I use Bio-Oss bone graft and Bio-Guide resorbable membrane to cover the cavity and place the last implant on the front side of the defect.
This is the final result after 6 months, ready for his general dentist to initiate the fixed prosthesis.
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.
Sinus lift surgery is done when there is not enough bone height to fix one or several implants in the upper rear sections of the mouth.
Placement of the implants can be done:
- simultaneously: remaining bone height over 4-6mm, good primary stability of the implants
- six months after the sinus lift surgery: the remaining bone height doesn’t stabilize the implants well enough (under 4-6mm, depending on bone density and with)
This case shows the placement of four implants on the left side, upper and lower, simultaneous to the sinus lift. the placement of the lower implants is reviewed in another article.
Several years without teeth on this side has completely altered the occlusal plane compared to the other side .
I open a flap on the gums big enough to approach the bone I want to treat.
The first approach is to drill and expand the crestal bone. Ostetoms are pushed carefully in to prevent the thin membrane that covers the inner side of the from breaking. This gives to signals. One is the bone density. The other is the bone height to the maxillary sinus.
If height, width and density are estimated to be enough as to stabilize the implants, as well as the bone graft, the graft can be introduced through these drillings and no further surgery is needed other than placing the bone graft and the implants.
In this case I estimated:
- Stability was good enough to place 4mm implants
- the leverage forces the implants would receive after load would be high, since the implants were to placed high up compared to the occlusal plane
- the amount and extension of the graft should be big enough as to provide support to these implants
So, I decided to lift the sinus membrane also laterally and insert the maximum bone graft material. A lateral window is open by drilling extremely carefully, not to break the membrane. The implants are placed and their stability is checked.
Thanks to the window I opened on the bone, the thread of the implants can be seen laterally.
I place the graft around the screws inside what used to be just air a few minutes before. The graft is made of lyophilized animal bone and some minerals. The body uses these graft material to crate self bone progressively. It takes about six months for this new generated bone to have enough strength to support load.
The lateral wall of the sinus is now folded up and above the implant threads, becoming the “ceiling” of the graft. Now we need another “wall” to close the “window” I opened and avoid the graft falling out and being reabsorbed without creating new bone. This is done by placing a resorbable collagen membrane over the lateral side.
Then, the flap is put back in place and stitches are used to close. They will be removed after 10-14 days, but the longer, the better, since the flap won’t stick to the membrane as it will stick to the bone.
The lower left implants are easily placed a little under the bone margin, to let space for the crown placement, since the occlusal plane is so damaged.
This case will need orthodontic treatment to lift the left teeth back in place, using the implants for anchorage. Once the occlusal plane is aligned, the crowns over the implants will be built.