Mirbod Periodontics & Dental Implants

Mirbod Periodontics & Dental Implants Dr. Mirbod specializes in surgical periodontics and implant surgery

December Cases of the Month:After a few months off, we’re diving back in with two case discussions. I picked these cases...
12/14/2024

December Cases of the Month:

After a few months off, we’re diving back in with two case discussions. I picked these cases specifically to highlight some common challenges and to get us ready for the new topics I’m planning for the upcoming year—like horizontal and vertical bone grafting.

Case 1:

I have discussed direct and indirect sinus lifts in detail in the previous months. Here is the case that I started using one method and ended up being completing with another method.
The patient is a healthy 54-year-old male with a history of recurring migraine headaches. I had previously placed implants for him at two other sites which were subsequently restored very nicely. He was missing tooth # 26 for many years (Figures 1 and 2). The space had closed up and at best it could be restored with a larger bicuspid (or a primary molar) sized crown (Figure 3). Also, tooth #25 showed Grade 2 mobility and bone loss presumably due to a vertical fracture in the root. In any case, the prognosis for this tooth was also poor. The residual bone height at the 26 site was 2 to 3 mm. I decided that I would carry out a direct sinus lift to increase ridge height at the 26 site. I should note that the Schnidarian membrane was very thick which oddly enough sometimes becomes more challenging when reflecting than a medium thickness membrane.

In any case, my objective was to carry out a direct sinus lift using a mixture of an allograft plus a xenograft. I always reinforce the Schneiderian membrane, after it is raised, with a collagen membrane. If the lift site is very large, I also combine the graft material with autogenous bone harvested, preferably from the tuberosity area. In this case, the site was small and the surgery was very uneventful, I raised a flap, reflected the membrane without any perforation as far as I could see or test, used a flexible collagen membrane to reinforce the Schneiderian membrane and used a mixture of an allograft and a xenograft to augment the sinus and increase ridge width. I used another collagen membrane with tacks on the bony window and coronally positioned the flap to cover the membrane and the window. I also extracted tooth #25 and carried out ridge preservation using the same allograft. The flap was flaccid enough that I coronally positioned it over the extraction socket. A periapical radiograph showed the bone graft in place (Figure 4). Although, I did not take a small field CBCT at the time as everything was very much normal as far as the surgery went. I placed the patient on a course of Clavulin 875F for 1 week and Peridex rinse for 2 weeks.

I saw the patient 2 weeks post-operatively and removed the sutures which were non-resorable. Patient had no problems with the surgery site, although he had a very bad episode of migraine headaches after the surgery, which responded to his usual medication.

I saw the patient for a revaluation in 4 months and a CBCT radiograph was taken (Figure 5). Much to my surprise there was no sign of the grafted material in the sinus. The graft material had either resorbed completely or was ejected through a perforation in the membrane. Usually if there is a perforation, the patient feels grafted material in the back of the throat. In this case he did not complain of any such side effects. I have looked into the literature to determine why this graft despite all the positive factors failed. From my understanding of the literature and talking to a few of my colleagues, I have concluded that whenever the membrane is relatively thick, there is always a possibility of some of the graft material getting embedded in the folds of the membrane after it has been raised. This results in a local inflammation which either contributes to resorption or perforation and subsequent exfoliation of the grafted material. In any case, I was now left with the situation that needed a remedy. My first response was that I will raise another flap and carry out another direct sinus lift. However, I will use a larger collagen membrane to exclude any folding of the Schneiderian membrane and subsequent embedding of the graft material in the Schneiderian membrane.

The patient was very understanding but he was very scared of having another episode of migraine headaches after the surgery. He asked me if it was possible to carry out a different procedure at this time. I discussed indirect sinus lift in detail with him and noted to him that he has only 2 to 3 mm of residual bone height which is usually not enough for an indirect sinus lift and immediate implant placement. However, if the indirect sign lift is successful and if I achieve primary stability, I will place both implants at the same time as the indirect sinus lift.

This time, I once again raised a large flap and prepared the 25 and 26 sites with Versa drills. The 26 site was prepared to 2.5 mm before I encountered the membrane. I used Novabone to initially lift the membrane at both osteotomies, doing both lifts at the same time. After that I used an allograft to further lift the membranes (Figure 6). Radiographically there does not appears to be any perforation present (Figure 7). I easily had 13 mm of sinus lift at both sites. However, I used an RP Nobel Parallel CC 11.5 mm implant at the 25 site and a similar 10 mm implant at the 26 site with cover screws (Figure 8). These two implants are to be restored with two bicuspid-sized crowns, preferably splinted together. I saw the patient in 6 months after this surgery for placement of healing abutments. Both implants had clinically and radiographically osseointegrated. In fact, I had to use a trephine to remove some bone on top of the cover screws (Figure 9).

This case remains somewhat puzzling, even though the outcome was highly successful. If I were to start over with this patient, would I do anything differently? The answer is a somewhat hesitant "No!" Typically, with only 2 mm of residual bone height, the instinct is to go for a direct sinus lift rather than an indirect one. However, this case demonstrates that even in such scenarios, it’s possible to perform an indirect sinus lift and successfully place an immediate implant—provided there is initial primary stability.

Case 2:

Here’s another fascinating case that took completely unexpected turns. In short, I had a treatment plan, but at every step, things unfolded differently. Luckily, the final outcome turned out to be excellent!

A 40-year-old male was referred to me for implant placement at the 31 site (Figure 10). He was suffering from periodontal disease in other areas and as such before even considering implant placement, we carried out extensive scaling and root planing which effectively dealt with his periodontal disease. As far as tooth #31 was concerned, extraction was the only option. However, radiographically, it is clear that we have both vertical and horizontal defects at the site. To make matters more complicated, the lingual plate has also resorbed which translates into a very difficult bone grafting. I have dealt with many cases of this nature with severe bone loss associated with mandibular anterior teeth. I usually extract teeth # 32, 31, 41, and 42 and place implants at 32 and 42 sites. Such a case will then be restored with a fixed bridge. In the long run, this is usually a good approach since ultimately, I expect teeth # 41 and 42 to also suffer periodontal disease. However, in this case tooth #32 also shows considerable distal bone loss which makes this site suspect for an implant placement. As for bone grafting to increase ridge width and height at the 31 site, this would be extremely difficult clinically because of the loss of the lingual plate. So, all in all, this would be a very complicated case surgically. The patient mentioned that he would be fine with any treatment plan that I suggested for him. This is more complicated because now the onus was on me to figure out the best option for him. As the patient is relatively young, I decide that before sacrificing other teeth, I might as well extract tooth # 32 and possibly carry out some ridge preservation to see if we can regrow bone on the distal aspect of tooth #31 which would make the area more amenable to a bridge prosthesis. I had very little expectation of vertical and horizontal bone growth at the 32 site to make this site amenable for a single implant placement. So, the treatment plan was as follows:

1) Extract tooth #32 and if possible, carry out ridge preservation using a mixture of an allograft and a xenograft and a membrane. I did not expect this to be a slam dunk procedure since there was no lingual plate present. Furthermore, there was still some suppuration from the site which would make the area less amenable to any type of ridge preservation procedure.
2) Following a healing period of 6 months, I would raise a flap, use a mixture of autogenous bone and a xenograft and a non-resorbable titanium reinforced PTFE membrane and possibly a connective tissue graft at the time of bone grafting with the hopes that I can regenerate vertical and horizontal bone.
3) Following a healing period of 6 months, I would then remove the non-resorbable membrane and either place a single implant at the 31 site possibly with further bone grafting at the time of implant placement or consider a fixed bridge if 31 site is still defective and tooth # 32 shows distal bone growth (i.e. implants at 32 and 42 sites for a fixed bridge).

Now back to reality, I raised the flap with verticals and extracted tooth # 32, degranulated the socket extensively and removed all infected soft tissue. As far as I could see the buccal plate had completely resorbed and there was a large fenestration in the lingual plate which had the thickness of an eggshell at best. In fact, I was surprised that the lingual plate did not completely come off with the lingual flap. Considering the extent of the infection, I decided not to place any ridge preservation graft material at the site. However, I used a resorbable membrane to stop the ingrowth of soft tissue from the buccal plate area. I was not sure if this would make any difference but at least I was hoping that I can stop ingrowth of soft tissue. The patient was scheduled to see me in 6 months for another CBCT and extensive bone grafting to increase ridge width and height. By the way, I did not mention that the patient was in film industry and was transferred to California almost immediately after this first surgery. Fortunately, I know a few good Periodontists in California and mentioned to the patient that he can see one of them to continue with treatment in 6 months time. The patient informed me that his job was for 12 months in California and he would be working 12 hours a day shifts. It would be very difficult for him to see anybody else and he would wait until he comes back to Nova Scotia. I saw the patient for a re-evaluation 13 months after the removal of tooth # 31 in my office in Halifax. A CBCT radiograph was taken which to my surprise showed some new bone growth, development of periodontal ligament on the distal aspect of two #32 as well as a robust lingual plate with a small perforation in this lingual plate (Figure 11). I was still planning to raise a flap and carry out bone grafting to further increase ridge width and height before placing an implant at the site later as per initial plan and the patient was in agreement with this approach. I raised the flap with verticals and noticed that there was possibly enough bone for placement of an implant at the site at this time. I placed a Nobel Replace CC implant at the site which achieved primary stability (Figure 12). Just to be on the safe side, I harvested autogenous bone from the synthesis area, mixed it with xenograft and placed on the buccal aspect of the implant with a resorbable membrane (Figure 13). I was able to coronally position the flap completely and cover the implant and the cover screw. Also, I noticed that there was adequate attached gingiva at this time and further soft tissue crafting was not necessary.

I saw the patient 6 months after first stage surgery to place a healing abutment on the implant. I was fully prepared to carry out further bone grafting to increase ridge width or height at the time of second stage surgery. However, there was no need for either bone grafting or soft tissue augmentation at this time since the implant was completely encased in bone and had clinically and radiographically osseointegrated (Figure 14). The patient was referred to the dentist for fabrication of a screw retained crown.

I shared these two cases to highlight that even the best plans often need to be adjusted during treatment. In other words, flexibility is truly a gift (Figure 15).

Looking ahead to the new year, I hope we’ll dive into a few cases focused on horizontal and vertical bone grafting.

Wishing everyone a Merry Christmas and Happy Holidays!

Case 7: August Case/Topic of the MonthThis month I will address a simpler topic compared to our last few cases. However,...
08/30/2024

Case 7: August Case/Topic of the Month

This month I will address a simpler topic compared to our last few cases. However, despite its simplicity, it is a very important topic. This is what I call “Ridge Preservation” or “Socket Augmentation”. I have heard the expression of “socket grafting” and I truly do not like this term. I have seen patients who required onlay bone grafting or guided bone regeneration following an extraction where the dentist carried out socket augmentation. They're inevitably confused as they say that their dentist performed “bone grafting”. They always wonder if this graft that I'm proposing is like that socket grafting procedure. I will have to always inform them that we are talking about two different procedures all together. Therefore, I would like to call what we are talking about here either socket augmentation, or more properly ridge preservation. I would reserve the term grafting for guided bone regeneration or on onlay bone grafting. This session will be in terms of questions and answers which might make the whole topic simpler.

1) Do we have to carry out socket augmentation or ridge preservation after any extraction?

The answer to this question is very simply, NO. There are those who advocate extraction without socket preservation. Their main argument is that after extraction “let the chips fall where they may”. They say that if there is a need after extraction, we will carry out onlay bone grafting or guided bone regeneration. They argue that there might not be a need for any of these procedures and as such socket preservation would have been a waste of time and money. On the other hand, there are people who carry out socket preservation for each extracted tooth.

I would not advocate either of these two extremes. There are situations where socket preservation is beneficial while there are situations where there is no need for such an endeavor.

2) When do we carry out socket preservation?

The first important point to consider is the patient’s interest in a future implant at the extraction site. If there is no plan to place an implant at the site, I would not consider socket preservation unless we are developing a pontic space for a fixed bridge. The second important point is the absence of ongoing infection. If there is any infection with suppuration AND it is difficult or impossible to remove all the infected tissue from the socket, I would not consider socket preservation. I have encountered situations where socket preservation was attempted in presence of infection and after months of healing there is a residual cyst at the bottom of the socket which must be now removed.
In absence of infection and if an implant is to be placed at a future date at the site, I would then consider socket preservation IF the buccal plate is thin or non-existent OR IF the ridge height is minimal and/or there is proximity of the maxillary sinus.

In cases of thin buccal plate, there will be definite resorption of the buccal plate. As such, it is important to augment the socket to minimize the reduction in ridge width following resorption of the buccal plate. If the buccal plate fractures during the extraction, it becomes even more important to consider ridge preservation to avoid further reduction in ridge width.
As for ridge height, in particular in the bicuspid and molar areas, if there is proximity of the sinus, reduction in ridge height following extraction is inevitable. Therefore, it would be beneficial to carry out ridge preservation to reduce the need for subsequent sinus lift procedures.

3) How do we carry out socket preservation?

This is probably the most difficult question to answer as there are so many different what I would like to call the “recipes” for socket preservation. Each one of them has some scientific validity and background. However, there is no one way which is the best way. To make matters more complicated, different companies produce different materials and brand them as the only way to carry out proper socket preservation. My approach is much more broad-based in a sense that I would use different materials and different routines for different situations.

A) As I mentioned if an implant is not to be placed at the extraction site, I would generally avoid socket augmentation unless we are developing a pontic space. In such a case, I would use a xenograft (bovine or porcine) with a collagen plug. IF we are dealing with an anterior pontic space, I would consider a soft tissue graft (connective tissue graft) to “plump” the tissue. No worries, if CTG can not be done at the time of extraction as it can be done a few months later. I should also note that instead of a CTG, one can use synthetic gingival products but they usually do not plump the tissue as much!

B) For simple extractions I would like to use an allograft and a collagen plug. I would suture the collagen plug over the allograft (possibly with some periacryl on the collagen plug). Not to make matters more complicated but I should mention that on occasion I use a non-resorbable membrane (dense e-PTFE) with or without an allograft for certain sockets. Non-resorbable membrane is more prone to infection and will have to be removed in 6 to 8 weeks. Once again if the gingiva is thin, we can consider a CTG at the time of extraction or later.

C) If the buccal plate fractures, I would then consider placing an allograft in the socket with a resorbable or non-resorbable membrane to cover the allograft and I would then coronally position the flap to cover the membrane. Covering the membrane is more important if you use a non-resorbable membrane. Once again if the gingiva is thin, we can consider a CTG at the time of extraction or more likely later.

What I have mentioned here is the backbone of socket preservation in my hands. Last but not least, I should mention that socket preservation is attempted only if I cannot carry out immediate implant placement. In other words, if I can place an immediate implant after extraction, that would be my first choice. Otherwise, I would consider socket preservation and delayed implant placement.

On October 24, 2024 in conjunction with Zimvie implant company, we are providing a course on socket preservation. Here is sign up info (figure1).

Case 6: July Case of the MonthAs I mentioned, with the advent of osseodensification indirect sinus lifts have become mor...
07/29/2024

Case 6: July Case of the Month

As I mentioned, with the advent of osseodensification indirect sinus lifts have become more predictable and common. However, it is imperative to be able to carry out direct sinus lifts as 1) you may have perforation of the sinus membrane during an indirect procedure or 2) there might be areas that require direct sinus lift as opposed to indirect sinus lift. It is far beyond the scope of our discussion here to completely go over direct sinus lift procedures. I highly recommend a course with a hands-on practical component for anyone who is planning to carry out direct sinus lifts. Personally, my favorite is the one by Dr. Michael Pikos. He is an Oral Surgeon who is very competent in surgical bone grafting procedures as well as soft tissue procedures. Most importantly he provides surgical steps to be undertaken when there is sinus membrane perforation.

When do we consider a direct sinus lift:

1) In the past, residual bone height was usually considered the determining factor. As I mentioned, there were people who would advocate direct sinus lifts when we had less than X mm of residual bone height where X was based on the practitioner’s preference (usually 5 to 6mm). This is not the determining factor anymore. I have carried out indirect sinus lift with 3 mm of residual bone height successfully and on consistent basis. As far as height goes in my opinion, anything below 3 mm of height you may have to be consider a direct sinus lift approach.
2) Number of teeth involved. If I am considering a sinus lift for multiple bicuspids and molars, I am more inclined to consider a direct sinus lift. In other words, if we have a long span lift, it is easier to consider a direct sinus lift as opposed to multiple indirect lifts.
3) If you need to carry out Guided Bone Regeneration to increase ridge width, and sinus lift to increase ridge height, it is best to consider a direct sinus lift in conjunction with GBR. Simply put, if you are considering GBR you might as well do a direct lift at the same time using the same material and setup.

What material to use for a direct sinus lift:

25 years ago when I started doing direct sinus lifts, we used to use autogenous bone exclusively. Soon after, the pendulum swung the other way, and we started using BioOss (a bovine xenograft) exclusively. The problem with the autogenous bone is that it resorbs very quickly and extensively. The problem with the BioOss alone is that it has the consistency of concrete and probably very few live cells. As such, I'm not sure if BioOss alone is a good medium for new bone growth and implant placement. At this point, the choice of material for me is very much dependent on the size of the sinus lift. If I am planning to carry out a small one tooth sinus lift, such as a single molar, I would use a mixture of Freeze-Dried Bone Allograft mixed with a xenograft in a ratio of say 70% to 30%. The xenograft will give a harder consistency to the graft and the allograft will presumably result in new bone growth. If I am considering a sinus lift for multiple teeth, I might use autogenous bone mixed with allograft and xenograft. If there is very little original bone to start with (i.e. 1-2mm of residual bone height) I might consider using growth factors. Obviously, the best growth factor would be a recombinant DNA growth factor (rhBMP-2) such as Infuse; however, amniotic growth factors such as BioXclude can also be mixed with the bone graft material for the sinus lift. As you can see, the less initial bone, the more likely I will use autogenous bone and growth factors mixed in with the allograft and xenograft.

On occasion, I have used an allograft in a gel carrier. This type of material is very easy to place in the sinus cavity but because of presence of a carrier gel, the percentage of allograft is relatively low. In other words, there's usually a carrier which could be from 30 to 50% of the material. At the end of the day, this is an allograft with easier handling characteristics. So it is definitely a good option for single or two teeth sinus lifts.

The other point to make is the use of PRF or PRP in sinus lifts. My feeling is that PRP is generally good for soft tissue healing more than bone healing. This is supported by literature and as such I am not very fond of these materials on their own for bone regeneration. However, one place that PRP is useful is sinus lifts. If we are carrying out a very large sinus lift, the use of PRP might be beneficial. However, a better material would be a recombinant DNA growth factor such as Infuse. It should be noted that the cost of growth factors is considerably more than PRP. So there is a use for PRP in sinus lifts. My observation is that there is not one single formula for each and every case. The larger the sinus lift, the more complicated the procedure and the more beneficial it is to use autogenous bone +/- growth factors +/- PRP.

Last but not least, sinus perforation is inevitable. It is essential to have a protocol for dealing with a perforated sinus. Here is where a course with a hands-On component is essential.

Case 1:
For this month we have one case which elucidates most of the points I have made thus far. A female in her early 40s was referred to me for a sinus lift in quadrant 1 for placement of 1 implant at the bicuspid site and 1 implant at the adjacent molar site. My rule is that if I am doing the sinus lift, I will also place the implants. However, in this case the patient was interested in zirconia implants which I do not place. She was referred by a colleague who places and restores zirconia implants but did not feel confident to perform a sinus lift of this magnitude (Figures 1 and 2).

A CBCT radiograph of the area revealed a residual bone height of less than 2 mm for the bicuspid and the molar areas. The ridge width was wide and did not require simultaneous guided bone regeneration. I should note that zirconia implants generally have wider diameter and as such a wider ridge is necessary.
I performed the direct sinus lift for this area using a large lateral window approach. I usually place a membrane on the existing sinus membrane for protection of the sinus membrane. In this case, I used a membrane with amniotic growth factors (BioXclude) on the existing sinus membrane (although there was no visible or functional perforation). A mixture of Freeze-dried Bone allograft plus xenograft plus amniotic growth factors (liquid form) was placed in the sinus cavity. After that, a non-cross-linked membrane was placed on the bony window and it was secured with pins. The flap was coronally positioned to cover this membrane passively.

Six months after that a CBCT of the area showed excellent increase in ridge width and height (Figures 3, 4 and 5) and patient was referred back to the dentist for placement of zirconia implants. The dentist placed 4.2 x 10 mm and 4.8 x 12 mm zirconia implants at bicuspid and molar sites, respectively which subsequently restored by him. I saw the patient 3 years later and took a CBCT radiograph as she needed other implants. There is still good bone growth around the zirconia implants (Figures 6, 7 and 8). My preference would have been smaller diameter implants, which are not available with this zirconia implant system.
By the way, when I place the implants myself after a direct sinus lift, I always use Versah drills to prepare the osteotomy site. This will result in a small amount of indirect sinus lift plus osseodensification of the osteotomy site at implant placement. In other words, after every direct sinus lift, the osteotomy is prepared using versah drills. Thus, the site gets the additional benefits of an indirect sinus lift plus osseodensification at the time of implant placement.

Address

Parklane Mall
Halifax, NS
B3J3R4

Website

Alerts

Be the first to know and let us send you an email when Mirbod Periodontics & Dental Implants posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Shortcuts

Share

Category