S03E01 Dr. Waldemar Polido - "Indications for zygomatic implants: a systematic review"

Dive into the publication "Indications for zygomatic implants: a systematic review" with Dr. Waldemar Polido published in the International Journal of Implant Dentistry. 2023 Jul 1;9(1):17.

Check the complete publication on the relevant databases:
doi: 10.1186/s40729-023-00480-4
PMID: 37391575

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Transcript

Amanda  00:04

Welcome to the ZAGA Centers podcast. Season three aims to explore the science behind zygomatic implants and the latest publications in this field. To this end, we welcome international scientific authors to discuss one of their publications and share their knowledge to progress clinically altogether.

David Pastorino  00:25

Welcome back to the ZAGA Centers Podcast. Today, we are welcoming Dr Waldemar Polido from the University of Indianapolis, ZAGA scientific partner, good morning. Dr Polido

Waldemar Polido  00:36

Good morning. Good to talk to you.

David Pastorino  00:39

Today, we're going to focus on one specific publication entitled indications for zygomatic implants, a systematic review published in the International Journal of implant dentistry in 2023. So Dr Polido, can you give us a bit of context around this publication? Where did you and your co authors identify the need to start working on this topic?

Waldemar Polido  01:04

Well, that's a great point. And again, thank you for the invitation to participate on this great podcast and speak with the listeners. So my experience with zygomatic implants dates back to 1999. This is when Professor Branemrk was developing all the training courses I was then living in South of Brazil city called Porto Alegre and and then the course was done by Dr Chantal Malevez in Brussels, Belgium, and Dr Peter Nielsen from from Sweden. And there I actually met Dr Carlos Aparicio on that course. So we have a photo of us together there. So my first zygomatic implant was done in 1999 when I went back to Brazil after training. And I had a good number of cases done after that, but the indications for it were always a bit, not very, very clearly defined. You know, when right at the beginning they were only for maxillectomies or extremely atrophic jaws. Then a lot of grafting became more popular, graft solutions, then short implants. Then, of course, the, you know, distally tilted or immediately tilted, pterygoid, all that kind of thing. So there was a need, I think, for a systematic review of the literature. Fast forward now to 2023, where I'm still involved in zygomatic implants now with the again, connection with Dr Carlos Aparicio and mentorship from him, but also other colleagues from around the world and the ITI, which is an association that we collaborate with, created this consensus conference on zygomatic implants, bringing worldwide experts on the zygomatic implant treatment, and my task was to review the literature based on indications. What were the indications? What were most clinicians documenting and publishing as the indications for zygomatic in terms of because that's when everything starts. You know, you can do it. You can report on numbers, but it's very difficult to report on the indications. If you don't know the indications, you're probably not going to have good outcomes. So once you select the proper indication, there's a higher chance everything will work fine. So I now as a full time professor in the maxillofacial surgery department at Indiana University. That's the name of our school here, Indiana University, Indianapolis School of Dentistry. Then we teamed up with a colleague that is a was a visitor here with me for a while, the Dr Lynn, which is a prosthodontist, and Professor Tara Aghaloo, who a maxillofacial surgeon from UCLA, Los Angeles, California, and I was the main author, and we reviewed the literature on it, and that that's how everything started.

David Pastorino  04:16

So the initial question, what are the indications for zygomatic implants? When I started reading the publication, I thought, that's easy, that's severe atrophy. And then when you go through the publication, you realize that this is a very wide range of anatomical situation and causes to this atrophy, and it's not that simple. So what was the process for that literature review that you started?

Waldemar Polido  04:41

Yeah, that's a great point. Because if you think, well, it's what's indication maxillary atrophy, that's easy, but what is a maxillary atrophy? Is it no bone? One millimeter, 2, 3, 4, 5, 6, for some people, six is already atrophic. For some other, six is okay. They can always put a six or a four millimeter long implant. They can tilt the implant. What is the anatomical configuration? So the main, the main focus of the study was to actually define the indications, but mainly define the what is a maxilla atrophy? What are the clear cases where we can use it like one clear indication would be a maxolectomy, right? Patients do not have a maxilla. That's kind of obvious, because then grafting solutions are way more complex and not as predictable. So that is one clear indication, but, but the other the day definition was posterior maxilla, because the main use of zygomatic implants for posterior maxilla number one. And then when do you do it? Like a quad zygoma fashion, where you put a zygoma that goes all the way to the anterior. So we had to look at different anatomical situations. So the main challenge, or the challenge was also, was actually not to define that, but to go over all the papers and read them carefully and see if they define clearly the indication, because a lot of papers and and we actually some of the authors of papers were in this big consensus meeting. They go out. You never quoted my paper. Well, your paper is great, but it never tells exactly what are the indications. You know, I did a zygomatic including patients where the maxilla was at least was less than four millimeters of height and less than two millimeters in width in the poster in maxilla premolar molars. So we needed that definition. So that is how it started. So we first reviewed, we had a strategy to select all the papers and and then we we went on and we had a minimum 10 patients with a minimum follow up 12 months. But mainly is that clearly, very clearly stated the indications for use of zygomatic implants. So while we consider papers that compare the zygomatic implants with bone grass, we consider oncologic rehabilitations, randomized clinical trials, prospective, retrospective case series, as long as they had at least 10 patients with a very clear definition of, of the indications.

David Pastorino  07:30

Okay, so looking at the Prisma flow diagram, I see the inclusion and exclusion criteria were quite strict meaning from 1266 publications and reports you identify only 10 that made it through the criteria. Does this mean that most papers don't mention a clear definition of the atrophy when they're reporting zygomatic implant rehabilitations?

Waldemar Polido  07:57

Yeah, that means that the precise indications were not reported. So we excluded reports that where the indication was not precise. They say maxillary atrophy without defining. Some papers had follow ups were less than a year. So we want to see where there was were indicated, but also worked. Some had less than 10 patients and and, and we only consider publications in English, so that's where all the the screens were. You know, we know how those things work. We just started with 1200 and something papers, and then we ended up with 10 at the end, which the indications are very, very clear and successful previous treatments, avoidance of stage bone grafts, but that was for the meta analysis, because actually the indications, we opened that scope a little bit, and then we went and reviewed clear indications, or some not very clear, but overall categories. So the next step was to categorize. What were the indications so we could have, like extreme bone atrophy or deficiency. 418 papers talked about that without perfectly defining, but they say, well, extreme. Then we went on and closed on the number of four, because most papers actually published less than four millimeters or less to be considered a potential candidate for zygoma instead of staged sinus lifts, unsuccessful previous treatments with grafts, grafts that fail, implants that failed, and those include old, separate also type implants. You know that that when they when they fail, they create immense bone defects and bone atrophy. And the sinuses are exposed then patients preference on avoiding staged. Grafting procedures also was one of the deep indications, because everything now is patient-driven, patients preference. And instead of going through a major bone graft, you could places that go my rehabilitate the patient predictably faster, especially with a new with a new type of implants, with the less invasive approach. So technique also changes throughout the years, and then obviously the maxolectomies and post cancer and post trauma. Also we here are a big trauma center, so we see a lot of patients that are post trauma, where they lose the teeth and the maxillo. So we have to deal with that.

David Pastorino  10:42

I'd like to come back on two points you mentioned. The first one is that in your search for the definition, or harmonious definition, of severe maxillary atrophy, I think in the paper, you found one number, an average number, the height of the crest in posterior, which is around four millimeters in average. But you're still missing another number, which is the width of the crest Exactly. Do you have anything to tell us on this? Yeah, it is. Is it something overlooked? Because it looks quite critical.

Waldemar Polido  11:14

You are absolutely right. It was not overlooked. It's just that nobody reports on it, because that is, that is one of the things that at the end, when we concluded, and then we have as as a consensus paper, we we suggest that better studies should be done reporting on the three dimensionality of the ridge. And another point that was brought up is that nobody ever reports on the different anatomy of the zygomatic bone, per se, only on the maxilla, but not all zygomatic bones are the same for different people. So some indications maybe the zygoma is very thin or is in a position that will make more difficult use of zygomatic nuance, then probably a graft. Maybe, you know, an indication So, but you're right. There is no report, I think only one paper reports on the width. So if you look in a panoramic, actually, let's say, and then you say, the height is eight millimeters, but the width is probably just, you know, one or two very horizontally, atrophic. You can still do a bone graft, but you have to depend on the type of prosthesis. You can just resect a bit of bone vertically and then go with this zygoma implant, or find, you know, do a technique with a flat in pen where it stays out of the sinus and just graft on the buccal those things so, but so that is a thing that, and that is a, I will not say, we did not overlook, but we saw that that is a deficiency in most papers, And nowadays, with CBCT and special software, it's not difficult to report on, on, on the three dimensional anatomy, yeah.

David Pastorino  13:10

The second point I'd like to come back to is something you mentioned about patient preference in the introduction of the paper. You mentioned that many of the publications you looked at mentioned the benefits of zygomatic implants as an indication, namely, immediacy. It's an immediate treatment, and that's why we did a zygomatic implant rehabilitation. And the question is not philosophical, but almost: Should we take into account the patient preference when looking at the indication for a certain treatment? I'm thinking in the market today, in the dental offices, in the private offices. I guess it's the most impossible to defend a bone grafting, online grafting, or iliac crest harvesting, with more than six months or a year of timed teeth and invasiveness versus teeth in six hours, one day, two day or even delayed loading. What do you think about this?

Waldemar Polido  14:11

I agree this is very philosophical, and it has a lot of marketing implications or market and also surgeons experience and patients preference I see sometimes in meetings or maybe even a couple of publications in not you know, in different journals that maybe some clinicians over indicate zygomatic events When you could just use a normal, classic, distally tilted, or maybe four normal anterior implants and then a couple short implants on the post cedar maxilla. In some orders, I think grafting like, let's say younger patients. If you have a patient that is, I don't know, 20, 21, 25 and technically, they have a lot of, you know, many years to live. And they do have an atrophic maxilla where the surgeon or whoever is treating this patient has good experience with bone grafts. Maybe reconstruction will be number one and leave the zygoma as an option for later in life, whereas, you know the same, like a huge defect for someone that is a little older, that already lost implants or and does not want to wait or has the option of maybe grafting, maybe a zygoma, that will be an indication, but that is, again, patient's preference, yes, because you're right, if you just ask the patients, do you want to get bone from somewhere, reconstruct, wait six months, no dangers for a while, zero teeth, or at least, you know, few weeks until the graft heal, plus dangers that are not perfectly free for a few more months, then the Inklings not always. You can do immediate loading on a grafted side. So you know worst case scenario to wait for us integration, and you may lose the graft. You may every time you increase treatment complexity, you increase the risk and but also increase patients expectations. Because the more treatment you do, you raise the bar as far as expectations. And if something goes wrong and fails, that's a setback, because it's cost, it's trauma, it's invasiveness, it's, I call it emotional expectations.

David Pastorino  16:37

All right. So I have one more curiosity about the publications, which was the percentage of delayed versus immediate loading on the zygomatic publications you identified, that was about 50% of each, meaning 50% would be delayed loading and 50% would be immediate loading. Do you think there is an effect, like average on time, where in the beginning, it would be more on the delayed loading side, and as of today, we're looking at almost 100% immediacy. Or can you think of quite a few cases where delayed loading is necessary today?

Waldemar Polido  17:17

Yes, that's a good, good evaluation, also, because we noticed that trend. So the initial papers, they were not with immediate loading as we progress. And most recent papers considered immediate loading as as a an indication. And this is a trend, not as an indication as an advantage. So see, 105 papers were had conventional loading, and 104 had immediate loading. So the most recent papers were mainly talking about immediate loading as a primary treatment option, because you don't that's the advantage of the immediacy. And colleagues like Edward Rosen Jay Neugarten, they all publish on the immediacy comp, the detail protocol for immediate loading. But again, that depends like I like to teach my residency and say that the immediate loading is something that has to be planned and prepared beforehand, but it can only be decided during the surgery, so that is a beneficial thing to the patients. And you know, I did a systematic review a few years ago on the number of implants for full arch restoration. And we also found that same trend when doing full arch not using zygomatic implants, just full arch treatment. We actually did not include zygomas for that one. It was the same type of finding, initial papers, conventional loading. And then after whatever date, I think the year, 2000 or so, then immediately became more and more and more used, popular and reported on. So it is an advantage. It is a consideration. You can plan for it whenever you can. But it's, it's based on the surgeon's experience, number one, to be able to achieve optimal primary stability. And then also, I think, based on the team experience and workflow, to be able to deliver their restoration in a timely fashion, to still be considered immediate. It links quite closely to the patient expectations, the emotional expectations, because if you promise and immediate treatment, zygoma treatment, meaning the patient, it's not his or her first visit at the office. They have a whole dental past. Yeah, they usually wouldn't trust the office that much anymore, and if you convince them, you present them, you know this is the right treatment option. Plus you would probably have teeth tomorrow, in 24 hours. Perhaps 48 hours if this doesn't happen, that's a lot of emotional expectations to manage. Yeah, that is why. And you see, unlike a private practice, we work in a academic training, education environment, so I have to let the residents do a little bit, and I also have the prosthodontist residence to do a little bit. They're not always we we do. We never promise to the patient that we will do immediate loading. We say this is we will prepare for it, if possible. We will do it, but we'll always have a plan B. Plan B, maybe two, three weeks without any dangers, and then we just capture and realign and deliver a conventional danger so that heals without any loading. Or we are able to do immediate loading, you know, up to seven days, technically, up to seven days still considered immediate loading. We do it as soon as possible. Sometimes we take impressions in the or adjust and deliver the you know, few days later, like you were in two separate practices. So the environment you work also plays a bit role on it of and then the experience, obviously. But the the key finding, I think, from the paper, is that yes, immediate loading is possible if you plan ahead, if you use the right protocol, and if you and if you have experience in achieving good AP distribution and good primary stability, it is a huge advantage compared to a staged bone graph, where you can ever do anything like that.

David Pastorino  21:36

All right, looking at the conclusion of the study, if you had to summarize what we learned from that study, what you learned from that study in one minute, and how does it apply to the clinical practice in the day to day protocols, what would it look like?

Waldemar Polido  21:55

I think the main thing that we learned is that zygomatic implants are, number one, predictable when you have severe atrophy. And the overall number, we actually just gathered numbers from papers that mentioned it is that four millimeters or less. And technically, again, this is based on our interpretation is very narrow regions, but also horizontally and vertically, atrophic. Then we learned that if you plan correctly, immediate loading is a possibility. We can do it, especially again, in the most recent papers, the way, using the Zaga techniques, using the approach correctly, using the you know, the advantage of now having round and flat ink designs that are helpful reducing complications and proper soft tissue management, everything that's good. We learned that there is a lack of information on a few things, so we propose new potential studies better defined anatomically driven zygomatic bone assessment, better defined three dimensional alveolar bone and sinus situation as well. And then, you know, and then we, we define, we ended, actually the paper, then that the final indication must consider the type of restoration planned. We actually do a lot of over dangers with zygomatic implants, they are all splinted, bar supported over dangerous and not fixed because of LEAP support and maintenance and that kind of thing. So that should be considered the anatomy of the ridge the zygoma, zygomatic maxillary region. Patients overall health and obviously the experience. So I also got lucky to be an author of a book that looks at the at the risk analysis for implant patients, the the straightforward, advanced, complex classification, risk assessment and implant density and zygomatic implies are very risky implants to place. So they should be managed only by experienced, well educated surgeons and restorative colleagues. So if you get proper education, proper training, and you you know, learn how to place them properly, they are a great tool to have in your armamentarium to treat this complex patients.

David Pastorino  24:22

Can you think of any bias or limitation to this study that would limit its scope?

Waldemar Polido  24:29

Yeah, there is always a bias. You know, there's a bias that we actually gather from from we do the risk of bias for the non RCT, and there is always every author, they do, have a bias towards their own experience and preference. Everybody that publishes its experience, surgeons. And we try to not put our bias on the discussion and everything, but there is obviously the way we read and interpret. So every study should be read with some care, but we try to be as technical and as detailed as possible. So someone that is a non experienced clinician but is interested, he will read it, and he will understand all the risks without and all the advantages without a bias. Yeah, use zygomatic insert everything, because that's not the point. So the point is to properly select what we wanted with the goal of this paper, which was just to get the indications out of it.

David Pastorino  25:35

I think we did quite a quite a nice tour of this publication, indications for zygomatic implants, a systematic review published last year in 2023 in the International Journal of implant dentistry. Thank you, Dr Polido, for the time spent on this publication and with us in the podcast.

Waldemar Polido  25:54

Oh, thank you, David. My pleasure to collaborate with the ZAGA Centers. Always, with you and everybody involved. So I hope people read the paper and my emails on the paper, and they can always contact us if there's any any need for further discussion, for sure.

David Pastorino  26:09

Fantastic. So let's give the audience a little time to go through the publication, and eventually you get a few emails with questions from them. Thank you again for your time, knowledge, willingness to share and have a great morning on your side of the world.

Waldemar Polido  26:26

All right. You too. Same for everybody listening. Thank you.

Amanda  26:33

Season Three aims to explore the science behind zygomatic implants and the latest publications in this field. To this end, we welcome international scientific authors to discuss one of their publications and share their knowledge to progress clinically, altogether.