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Histologic Wound Healing After Ridge Preservation with Dr. Brian Mealey
420 Plays9 months ago
What factors affect the formation of new bone after ridge preservation? Listen as Dr. Diego Velasquez, Co-Editor of Clinical Advances in Periodontics, and Dr. Brian Mealey discuss healing time, graft material, and the importance of remembering that patients do not necessarily "follow the mean".
Read the full article here. https://aap.onlinelibrary.wiley.com/doi/10.1002/cap.10281
This podcast is produced by the American Academy of Periodontology. To learn more visit perio.org.
The views expressed in this episode are those of the participants and not necessarily those of the AAP.
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Transcript
Introduction to Periodontics Insights
00:00:00
Speaker
Whether you are in training, in practice, or in research, the Journal of Periodontology and Clinical Advances in Periodontics have something new for you.
00:00:34
Speaker
Hello,
Meet Dr. Brian Milley
00:00:35
Speaker
everyone. um It is a pleasure for me to be sharing this space with Dr. Brian Milley. Professor Milley is not only a colleague. I consider him a good friend. He is a clinical professor at UT Health San Antonio, part of the System of the University of Texas. And he is the main author of a paper that we're going to be sharing with the audience today. The paper is titled,
00:00:58
Speaker
histologic wound healing in studies using different rich preservation protocols, a review. This is a paper that is authored by Dr. Milley as well as Dr. Killing and Dr. Palalogo.
Histologic Wound Healing Study
00:01:12
Speaker
With that said, I would like to start a series of questions that will help us understand All the details behind this beautiful paper that was recently published in Clinical Advances of Periodontology, this was published just a couple of months ago. And the first question I would like to ask Dr. Milley is, could you please provide us a background on the nature of this paper? i In other words,
Research Journey and Focus
00:01:37
Speaker
what is the compilation of all the work? How long ago did you start this work? And how did this come to happen, please?
00:01:44
Speaker
Yeah, well, we started the the first project we started was in 2007. So it's been it's been quite a while. And since we started, we've had 21 different residents have participated in these studies. And we published, I think, 19 papers so far. And we're working on the 20th one now.
00:02:03
Speaker
Importantly, over 800 patients have been part of these studies. So ah we got started because um on a dinner napkin, I wrote down this idea because I heard somebody say at at a lecture, you know, if you wait longer after rich preservation before you put your implant in, you have more bone there than if you wait a shorter time. And I thought, I wonder if anybody's actually ever shown that.
00:02:30
Speaker
So wrote it down on a little dinner napkin and then came back and said, let's take a look at it. So that's kind of where it started. And that paper, you know, as you know, uh, Diego, you ask, you answer a question and you got two new questions that you think of. And so that's kind of where it began. And and the whole focus has been directed towards, towards wound healing. We don't really look at implant outcomes. We're looking at wound healing outcomes.
00:02:57
Speaker
You know, it's my opinion if if if my doctor implants something in me, I would like her to know why she implanted it in me based on some data. So that's what we were trying to do.
00:03:08
Speaker
Fantastic. Thank you.
Individualized Patient Treatment
00:03:09
Speaker
And what would the word do with would be without napkins, Brian? It is amazing. that's true So when I'm looking at the results, several of the papers, the original papers, and of course, in this compilation and this review that you wrote, they always mention average values such for instance, the average of bone loss, the average of bone gain,
00:03:32
Speaker
vital bone formation, residual graft material, et cetera. What is the downside of thinking in terms of averages when we are dealing with clinical realities, Brian? ah Right. So, you know, I always say that science is about means and standard deviations, but clinical practice is about Mrs. Gomez in room two tomorrow morning at eight o'clock.
00:03:52
Speaker
And
Bone Loss and Resorption Studies
00:03:53
Speaker
so one of the problems I have with evidence-based dentistry, the way it's sometimes understood is that it is somehow true, ah meaning not just factual, but but true, meaning it's going to apply to everybody. And you know if you just think about a normal bell curve shape population, if my practice is a bell curve shape, then the the average, which let's call that the mean plus or minus one standard deviation, how many of my patients are going to fit into that at that average?
00:04:23
Speaker
statistically at 66.7%. So that means fully one third of the patients in my bell curve shape practice don't fit the mean. So I think it's it should be our expectation, not a surprise, that individual patients do not follow the study that we happen to have just read. So when we talk in these papers about mean and standard deviation,
00:04:48
Speaker
I don't ever like to apply that to that patient on that day. The mean is 32% vital bone. Do I actually expect to get that when I do ridge preservation for Ms. Gomez? I don't. I expect it to be somewhere within the one standard deviation, except if she's an outlier patient who may have more vital bone or less vital bone, for example.
00:05:10
Speaker
That's a great point, always thinking about the individual and treat them as such. yeah Thank you. In this paper as well, you give credit to a classic paper that I consider classic, that paper written by Mauricio Araujo back in 2005, which is that an animal study, a dog study. What would be the take-home message from this classic paper, Brian, in your mind? Yeah, that was that was a really important series.
Healing Timelines and Implant Decisions
00:05:34
Speaker
So I think what I got out of that was kind of physiologically, why do we lose bone when we take out a tooth? Physiologically. So you and I both remember Dr. Lindy speaking about those papers and used to say, the bundle bone belongs to the tooth. So we think about the the sharpies fibers that insert from the tooth to the bone. Those insertions in the bone, that bone is bundle bone with the bundles being the bundles of collagen fibers. So when they when we take the tooth out,
00:06:05
Speaker
those fibers are gone. And so that bone resorbs because they no longer have that function. So if we think about thin bone, like let's say in the most coronal aspect of a maxillary first premolar where it's really thin bone, most of that bone thickness is being made up of cortical plate and bundle bone. And so if if if it's not really thick and has more than just bundle bone, when we take the tooth out, we lose the bundle bone, which means we lose vertical height.
00:06:34
Speaker
And then when we measure the width where we've lost the vertical height, you see a loss of bone width as well as the height. So that was a seminal paper to me. That is classic. And I always enjoy the detail of those descriptions and exactly all the physiology that happens from the blood clot formation all the way to all the changes that you just described. Thank you, Brian. Now, with the knowledge that we have nowadays in 2024, how much time should we wait after alveolar rich preservation procedures are performed before we place a dental implant? And what is the rationale behind this timeframe? For instance,
00:07:11
Speaker
There's a variation. You mentioned in one of the papers that there was a large variation that was observed between the three month versus the six month now timeline. And the authors decided to collect start collecting data in some of these papers at the 18 to 20 week timeframe. How was
Donor Variables in Bone Grafts
00:07:28
Speaker
that decision made? So the the first paper that we did, Dr. Tina Beck, who now practices in San Diego, and she was really foundational for this for this whole series that we did.
00:07:39
Speaker
ah we We decided to look at that three month versus six month. Is there a difference in vital bone formation, residual graft, and what we called connective tissue slash other. We'll just call it CT for for today's podcast. And what we found was completely counterintuitive. And that was there was no significant difference in vital bone formation or residual graft percentages at three months versus six months. And we thought, well, it should have been more at six months. But it wasn't with the particular bone graft we were using for that study, which may not, that may not mean anything about the bone graft that you're using in your practice. That was a single study. But so a lot of people said what we had in our mind was that was a timing study, single protocol being used at three months versus six months. We also though wanted to do studies that looked at different protocols at a single time point. So the question then became what time point are we going to use for those studies?
00:08:37
Speaker
So some people said, well, since you showed no difference between three months and six months, you should use three months because it's shorter. You get the study done faster, et cetera, et cetera. But the reason that I decided on this 18 to 20 week time period was when we looked at the individual bone cores in that particular study, while the average vital bone formation was similar, no significant difference between the three month and six month group, the inter individual variability,
00:09:05
Speaker
in the percentage of vital bone and residual graft from one core to another was huge. So we may find an average of 43% vital bone, but I had some cores that were 18% and others that were 82%. So I didn't feel comfortable saying, let's just pick the three month one because it had as much variation as the six month group did. So this decision actually was relatively arbitrary, but it did come from the thought of let's pick a spot between three months and six months. So that's kind of where we ended up. It's not very scientific, but that's where we ended
Membrane Materials in Studies
00:09:41
Speaker
up. Very salamonic. I like that.
00:09:43
Speaker
now Now, in several of your studies, the age of the tissue donor is mentioned. Why is that important? Why should we keep that in mind as an audience? Should every practitioner be requesting this type of information when acquiring allograft material? And what is the ideal age range to maximize the best outcomes? So ah back in the late 1990s, and Diego, you know these people, Dr. Svi Swartz and Dr. Barbara Boyan, who were then in our department San Antonio,
00:10:15
Speaker
did very important research on the inductivity of demineralized freeze-dried bone, looking at end in yeah variation in inductivity between different tissue donors and different tissue banks, and relating the inductivity to sex, male versus female, as well as age. And what they found was that on average, there was really no difference in the inductivity between men and women donors.
00:10:40
Speaker
But when you looked at age, there was a difference with higher inductivity in younger donors than in older donors. So the for clinicians, the question is, well, gee, Liz, I only want to use bone from from young donors. I mean, that kind of makes sense on average. The problem is is that making that happen is difficult. So most of the tissue banks have age limits for certain types of tissues being donated. so that they may say, well, our age limit for this type of tissue is 65. So if the donor is over 65, we won't use these tissues. ah Other tissues may be less than 50. So, um, so one of the problems for a clinician is, is are you going to go to your bone distributor and say, Hey, I'm not taking any of your bone graft unless the donor is less than 40. Go ahead and try that, but you're not going to get very far.
00:11:32
Speaker
ah For one thing, you and I, by most of us buy our tissues from distributors, not from the tissue bank. So a tissue bank ah may have 10 distributors, you know what I mean? So I don't think, um ah I'll tell you what, I've tried to do a study with this exact thing in mind about looking at different age donors in in the model we've been using, the rich preservation model.
00:11:59
Speaker
Problem is you have to have a lot of patients to do a correlation that's actually going to be meaningful. You know what I mean? So I i think that, um I mean, the one of the things we did in these studies that I think is important is that, ah because I'm not sure any other research group did this, is in in our second study, ah I wanted to specifically work with a, let's say a tissue bank,
00:12:26
Speaker
but from which I could obtain all the bone that was going to be used in the study from a single donor. That way, that variable was gone. So, so ah so ah you know, the other variables might be there like the bone may be mineralized versus demineralized, but it came from the same donor. It was ground to the same particle size. So the only difference in that particular study was going to be how much residual calcium was present in the final DFDBA versus
Study Findings Across Different Sites
00:12:52
Speaker
mineralized FDBA. And since then, almost every study we've done, we've been able to get a single donor. And the tissue banks are have always been willing to share with me the age, the sex, and sometimes the cause of death as well. So that's that's why we report it.
00:13:12
Speaker
Thank you so much. That's such a great point and and something that it is not easily identifiable as a variable in some of the literature that is being reported. And again, trying to compare apples to oranges becomes more complicated, lacking that type of data. So thank you for for expanding on that. Much appreciated.
00:13:28
Speaker
now I also noticed that there was an evolution. In the beginning, the graft sites seem to have been protected utilizing a collagen sponge. And all of a sudden, after a a certain number of studies, then a dense EPTFE barrier starts being utilized. And I was just wondering, why was that change incorporated in the protocols? And also, how was that?
00:13:51
Speaker
non-resorbable membrane handled? Was it tucked under the tissues? Was it sutured into the flaps? How did that go, Brian? When we first started doing the studies, I think it was kind of pretty conventional in our perio practices to use a collagen sponge. It's fairly simple. It's inexpensive, et cetera. When the DPTFE membranes first came out, we started using them just like you did, I'm sure. And we found them pretty darn nice for handling and the the kind of the tissue when you when you it's healed so we decided to stay fairly contemporary with practice and start to use those and when we did we we would reflect the flaps using not more than about three millimeters from the from the bony margin and we would tuck the membrane under both the facial and the
00:14:40
Speaker
lingual or palatal flap, and not currently advance the flap. Some of the studies, Jago, we also used resorbable collagen membranes, not the wound dressing, but a collagen membrane, and those would be tucked underneath the flap margins, similar to the dptfe membrane. Very good. Thank you for thank you for explaining that.
00:14:59
Speaker
Now, when we're looking at most of the studies were performed in non-molar sites by caspids, if I'm not mistaken, probably the the tooth of choice. And I was wondering, what are your thoughts in extrapolating data when you're looking at, for instance, this type of research design compared to mandibular incisors or compared to maxillary incisors with a very delicate phenotype?
00:15:23
Speaker
or even just mandibular molars when you have a different scenario, different morphotype as well involved with these type of procedures. Yeah, when, again, when we first started, because, excuse me, this model was relatively new, you know, ridge preservation, ah you know, a four-walled socket being used to look at wound healing outcomes. So ah we wanted to keep the complexity, let's say, or the variability in the socket shape and size to a minimum, if we could.
00:15:54
Speaker
So that's why we started with non-molar teeth, which could be the premolar all the way around to the other premolar. It just happens that we take out a lot of premolar teeth in periole. And so that's why there is a predominance of premolars in the non-molar tooth studies that we've done.
00:16:15
Speaker
So that's why we started that way. My other concern was this. You know you think about a mandibular molar. So you've got two roots, and a lot of times those roots are actually fairly narrow if you compare it to like a K9, a max-rate K9, until you get to the root trunk. And then it's huge. right you know And so again, that variability was what led us to start with non-molar teeth. As we moved along, we did a series of four studies that were specifically done only in molars.
00:16:45
Speaker
ah to kind of look at different protocols as well. And then we did ah a molar study for a product that we were looking at particle size. And you pretty much had to use a molar because some of those particle sizes were pretty big. And so that was just a practical thing. My sense of our data is that the wound healing events that happen ah ah the wounding link parameters that we look at, histomorphometrically, there's not a whole lot of differences between molars and non-molars. Now the clinical measurements, ridge width, et cetera, right may be different due to the thickness or thinness of the buccal and lingual plates in molar sites versus, let's say, a maxillary canine. But ah the numbers kind of show us there's not that much variability in vital bone formation.
00:17:32
Speaker
in um
Analyzing Bone Formation and Future Research
00:17:33
Speaker
in you know in the cores we take at the osteotomy site between molars and non-molars. Thank you, Brian. I appreciate that. Now, you mentioned the histomorphometric data. And this is something that when we read these type of studies, we're always looking at vital bone formation, residual grafts, connective tissue. And these are mainly the sources of all the data points.
00:17:55
Speaker
Why is this important, right? And if you could please share with the community, why are these data points important? And are there any other factors that perhaps we could include in future research that might give us better information or equal information that we might be missing as far as healing and the quality of bone formation and perhaps in anticipation of a better implant to bone contact? Right. Well, one of the reasons I started with those parameters is because your mentor and mine, Dr. Jim Melanie,
00:18:24
Speaker
I had a big influence on both of us. So when I first came out to the school after retiring from the Air Force, I sat down with Dr. Melanig. He was still with us when we started this first project and said, you know, I'm thinking about this study. What parameters do you think we should look at? Well, he and Dr. Bowers had looked at percent vital bone, percent ridual graph residual percent CT and other. So if you have a master,
00:18:50
Speaker
suggesting that that's what you should look at well my gosh that's what you're gonna look at so so we did and one of the things you know I've thought over time it would be nice to be able to count osteoblasts for example you know if you think about the the newly forming bone that you have ah how many osteoblasts do you see that that's obviously a little more difficult to do you have to look at really high power that type of thing which wasn't practical for us in the way we were doing the evaluation, but you know that's something you could you could certainly look at. You could do immunohistochemistry if you were interested to drill down into some of the more basic sciences of what proteins are present in this this newly formed bone versus for perhaps a site that you didn't do ridge preservation in.
00:19:39
Speaker
And you look at that vital bone. You know what I'm saying? Right? Yep. You know, this may not be the right venue, but I'm a clinician. So I kind of tend to care about the wound healing outcomes that I think will directly translate to the clinical procedures we're doing. In this case, ah you know, implants. Again, our studies are not implant outcome studies. They're wound healing studies. But I think that all of us are concerned when we place an implant Is there going to be vital bone there you know when we place it? And we may talk later on about other issues but related to that. But that's why I started with those three primary histomorphometric parameters.
00:20:22
Speaker
That's fair, and thank
Selecting Graft Materials and Ratios
00:20:23
Speaker
you for the insight as far as some of the factors that we could be looking at as well to get better understanding of what's happening with those details. Moving on, there was a paper that Dr. Holman published together with you in 2012. And in this particular paper, a demineralized bone matrix putty was utilized with very positive outcomes when it came down to vital bone formation.
00:20:47
Speaker
My question to you is, what are what are your thoughts with the carriers that are being utilized nowadays or perhaps future applications that can enhance these type of results?
00:20:58
Speaker
We've kind of gone through the putty and paste era. You know, yeah you remember when that first started? And and I wish we'd have thought that up because we're pretty smart as dentists, but we didn't. But orthopedics started that. So a lot of what you and I and and the people listening do in the oral cavity has been preceded by our brothers and sisters in the orthopedic world. So they started it. and I like the handling properties of putties and pegs. I think that's what that's why most of us use them if we do use them. Here's a question for you. If I take a ah premolar socket and I use a bone allograft that's particulate and I ah fill the socket, I have a volume of X particles, correct?
00:21:41
Speaker
Now, if I use a puddier paste, I no longer have a volume of X particles. What I have is X minus the paste is what my particles are. Does that matter if you compare a paste with, let's say, a demineralized paste versus a demineralized particulate? Does that matter? that That's a project that I've wanted to do for a long time and just haven't yet.
00:22:09
Speaker
ah because ah most clinicians really don't seem to find much difference when you're drilling the site, where you know we used a paste or a putty. um So I hate to say it, but I'm kind of a particulate guy. if i If I want X amount of particles in there, if I just put that much particles in there, I'm good to go. so and And most of the the defects we're dealing with when we take a tooth out are contained.
00:22:35
Speaker
You know what I mean? Do you really need a putty in a contained defect versus perhaps an open sinus augmentation or closed sinus augmentation? Where those putties, the flowability of those putties may be really nice from a handling of property standpoint. A much better application. I'm glad you mentioned.
00:22:53
Speaker
The ah reality that we have learned a lot from the orthopedic surgeons, I remember Dr. Melornico you mentioned, he was an avid reader of that literature and I think a lot of that came from that field. especially what us to yeah cross Cross fields and continue learning.
00:23:09
Speaker
Another question that I had as well when I was reading the ah the body of your of your research was, in some of these papers, you're utilizing a combination of grafting materials. For instance, you're utilizing some demineralized and mineralized bone, and the same thing with cortical or cancellous bone. My question to you is, what are the advantages of these combinations, number one? And number two, how how have we come to determine the appropriate ratios?
00:23:38
Speaker
The first, um one of the first studies I wanted to do looked at demineralized bone versus allograft versus mineralized FDBA. Because periodontists, you know, traditionally use DFDBA for periodontal defects, right? yeah And our oral surgery colleagues, they didn't. I mean, they've used mineralized bone forever. Demineralized is not really something that's been as that bigger a thing for them so So, Rob Wood, who practices up in Utah now, he and I did the study where we looked at demineralized bone versus mineralized bone, all from the same donor. ah The only difference in those two products was the percentage of residual calcium, and we looked at those at that 18 to 20 week time period.
00:24:22
Speaker
the The results of that study showed that there was a significant increase in vital bone formation when you use demineralized freeze-dried bone versus mineralized, like 50% greater. So I said, well, gee, look I switched. I actually stopped using mineralized bone and started using demineralized FDA because of the results of that study. The problem is, is you and I often work with referring dentists. right So we take a tooth out, you read preservation,
00:24:49
Speaker
we place the implant, let's say four months later, we take a radiograph and what does it look like? With two vertical bony defects on the PA because the DFDBA is not mineralized yet. So it's kind of spooky, you know, just to look at an x-ray. Even though, you know, you open the site and put the bone, the bone was plodded as a rod. Just practically It got us to thinking, what if we had a combination of demineralized bone for this kind of inductivity aspect and mineralized bone, one reason because it's radio opaque. So we got together with ah one of the the companies that has supported some of our research and suggested that, and they had actually been working on that. So again, we don't come up with new ideas, it seems like. Somebody else has always thought of it.
00:25:41
Speaker
but But so I got together with them. They had done some animal research looking at different percentages of the mineralized and demineralized components. And the 70% mineralized and 30% demineralized was kind of what they and other tissue banks had come up with as a, ideal is a terrible word, but a good combination of the two. Could you have used 50-50? Yeah, probably. So, but the 70-30 product,
00:26:08
Speaker
was just out on, I mean, it had just literally come out on the market. And so we Tyler Borg, ah who practices in Denver, and I did the project looking at that 70-30 compared to 100% mineralized. So 70% mineralized with a 30% demineralized combination versus 100% mineralized freeze-dried bone. And what did we find? The addition of that small amount of demineralized bone and resulted in increase in vital bone formation,
00:26:38
Speaker
18 to 20 weeks after ridge preservation compared to 100% mineralized. So that's kind of where this com combining started. Same thing in the cortical versus cancellous. That's a big fight in
Graft Processing and Integration
00:26:51
Speaker
orthopedic. you know Should we use cortical? Should we use cancellous? Each one has good properties.
00:26:56
Speaker
And so ah Adam Esco and I did a study looking at 100% Cancellus versus 100% cortical. This was before the combinations were out, right? We showed there was no real difference in the vital bone formation, but there was greater residual graft at the time we placed the implant in the 100% cortical group.
00:27:18
Speaker
So once the 50-50 Cancellus product came out, and I'm not exactly sure why that combination was chosen versus 90-10 or whatever, okay good but that's what was available. When that came out, we did a three-arm study. Randy Demeter and and Blaine Callahan and I did a three-arm study, 100% Cancellus, 100% cortical, and in the middle, 50% Cancellus and 50% cortical.
00:27:43
Speaker
we found again on average there was no difference in vital bone formation between the three at 18 to 20 weeks after ridge preservation but there was a higher percentage of residual graft in the hundred percent cortical compared to the other two. So I think if we're using a hundred percent cortical, which I do use, we should expect those particles to stick around for a longer period of time than the Kincellus does. Does that make sense? Absolutely, which might be a positive thing. It might be a positive characteristic. It could be, especially in some applications. do You have a big distance, for example. So maybe that's a time you want that to stick around. Dimensional stability, perhaps. Right. Or exactly. It could be. Thank you. Appreciate you you elaborating on that. That's something that I was wondering myself and appreciate you you expanding on that. Yeah. Now, went what what are the implications of the different processing techniques, for instance, for allograft dehydration? Specifically, we have recognized two main ways to do that, the freeze drying fashion and the fashion utilizing a solvent dehydration approach. Is this something that we should be, as practitioners, we should be asking our purveyors of bone what type of technique are you utilizing and what would be the rationale behind that?
00:28:57
Speaker
I think it's it's always a good idea to know what's in the bone we use. When I see product representatives come to the office, I really want them to know what's in their bone too. And so if we don't know what's in the bone, we we can't always fact check them. But traditionally, freeze drying was used. And freeze drying can have some effects on some of the properties of the final allograft. So the solvent dehydration process kind of came up as a way to maybe using this process, there there will be less alteration in the final
00:29:33
Speaker
product. So there are solvent dehydrated allografts that a lot of periodontists and other dentists use. And so um so does it really make a difference when it comes to vital bone formation? We did a ah specific study that looked at that. Solvent dehydrated versus lyophilized or freeze dried ah mineralized allograft. And what we showed in our, this is just one study, and this is the average, we showed no average difference in vital bone formation or residual graft. and That particular study we did at 12 weeks, plus or minus a week or so, instead of 18 to 20. So why do we do that?
00:30:13
Speaker
We thought that the if there was going to be a difference between solvent dehydrated and laugholized freeze dry bone, maybe that difference would be more evident earlier in the wound healing process. Does that make sense? So that's why we did that study.
00:30:28
Speaker
a little bit earlier than our standard 18 to 20 week. That one was done around 12 to 13 weeks after the reservation. We didn't really find a difference. So if you're a solve it guy, knock yourself out. If if you're a lyophilized person, that's okay too. I don't think there's really that big a difference.
00:30:45
Speaker
Fantastic. Thank you. that That is a great answer and something that I think some of us have been wondering about. The other aspect when we're doing when we're dealing with graphs is the particle size. That has always been a focus of interest. How big is too big? And how is small is too small for a bond particle? And what are the clinical implications of, for instance, with absorption speed or sequestration, et cetera? What are your thoughts on that?
00:31:12
Speaker
Yeah, you know how you can tell out clinician a dentist is a periodontist? It's because they ask about particle size. Because we kind of did that, remember, in periodontology. We didn't. We didn't. But our researchers, our colleagues did that. right and And so ah I think a summary to that would be this. um We want, when we when we when we grind the bone to a certain size, we'd like to get a particle size that allows, when we put it all in the defect, that allows spaces, pores,
00:31:39
Speaker
for angiogenesis, for new blood vessel in growth. We want there to be pores present. And the more we grind it, the greater the surface area becomes, right? So that's a good thing. The problem is if you grind it too small into the socket, now it's like putting sand in the socket. So once it soaks in with blood, it gets packed in like wet sand. So there really aren't pores for the blood vessels to grow through. So too small may get you a lot of surface area, but no blood vessels.
00:32:09
Speaker
so So we don't want too small. the larger the The larger size gives you less surface area but more pores, right? And then there's the practical app applicability of, you know, most of the graph we periodize use, Dennis in general, is usually about 250 to 1,000 microns, right? but For some
Healing Timelines and Implant Placement
00:32:29
Speaker
applications like ridge augmentation, sinus augmentation, you may want even bigger particles.
00:32:33
Speaker
but Most of them are that size. Because if you get much bigger, if you go with two to four millimeter particle sizes and try to stuff those into a lateral incisor size, good luck. You know, you get two particles in and that's it. So ah so I think that's kind of the poor thing. And and the tissue banks get that. I mean, they've they've done that research. So what we're getting, that 250 to 1,000 microns, I think gets you the best of both worlds. Lots of surface area, lots of pores.
00:33:02
Speaker
Great, great summary with that. Appreciate that. Now, if we wanted to accelerate healing times because we live in a society that we want everything immediate, everything needs to be done right now and we cannot wait three months, four months for anything to heal. If we wanted to accelerate the healing times, can we make that decision by choosing a type of grafting material of the stuff that we have available in our storage, in our Yeah, let me let me talk about it from a wound healing standpoint, not from an implant outcome standpoint. I know a lot of us are kind of antsy. ah you know We take the tooth out, we do the ridge preservation, and by gosh, we want to put an implant in tomorrow you know if we could. ah but So how long how long should we wait? And then can we shorten the waiting time by using a particular protocol on site? So when Dr. Wood and I did the mineralized versus demineralized freeze dried bone,
00:33:57
Speaker
We found so much higher vital bone in the demineralized group versus the mineralized that we started thinking that. What if we, instead of doing 18 to 20 weeks, what if we shorten it to eight to 10 weeks and see what happens? Because we got so much bone at 18 to 20, maybe we still have a lot of bone at eight to 10 weeks. So we did that study. Jeremiah Wetman, who practices out out in Arizona, we did that to say, let's look at 100% demineralized bone.
00:34:26
Speaker
from a single donor, ridge preservation, implants placed at 8 to 10 weeks versus 18 to 20 weeks. So what did we find? We found what your intuition would tell you. The shorter wound healing time period period had less vital bone, a lot less vital bone compared to the 18 to 20 week. But even though it had a lot less vital bone, it was still a lot of vital bone, even at that short time period.
00:34:51
Speaker
so So then but we we moved on and looked at the 70-30 combination, right? So we had shown, again, vital bone formation, looking at 100% mineralized, the 70-30 combination, and 100% demineralized bone. There was a difference in vital bone formation at 18 to 20 weeks.
00:35:11
Speaker
So we took the 70-30 and did the same protocol ah that we did with 100% demineralized, where we did the 70-30 combination at 8 to 10 weeks.
00:35:21
Speaker
and 18 to 20 weeks. Dr. Aaron Nelson, who practices out in Phoenix, did that study. And what did we find? Kind of what you would think. Less vital bone at the shorter time period, right? So so in the end, what we found is this. Sorry is for such a long answer. No, this is good. if yeah If you have ants in your pants and you have to get your implant in quickly, you can do that by using 100% demineralized bone.
00:35:47
Speaker
If you, you can also, compared to mineralized bone, you also at a short time period can use the 70-30 combination. You won't get as much vital bone as you did with 100% demineralized.
00:36:02
Speaker
But it'll still be more than you have with 100% or up. You won't get as much with the combination, right, at the early healing time point, as you do with 100% demineralized bone. But you'll have more with the combination you would with 100% mineralized bone. So again, if i if I really need to get my implant in soon for some reason,
00:36:22
Speaker
And the radiographic appearance is not going to freak out your referring dentist. I personally would use 100% demineralized allograft. Now, from a clinical standpoint, this is not science. this This is just, we've done a lot of these. The tactile sensation of drilling the osteotomy at eight to 10 weeks, whether it's D-men, 100% men, or a combination of the three, is it's often quite soft.
00:36:49
Speaker
And it's a little freaky when you, when you drill that and it kind of just goes in like it's jello. The good news is, is most of us place a longer implant. Our osteotomy is deeper than the original socket depth. So we're using apical vital bone to help anchor the implant like we do in an immediate implant.
00:37:08
Speaker
correct So I think so long as you have a site that you have some good native bone apical to the former socket, that softness, if you will, of the osteotomy drilling doesn't really bother me. Our implant outcomes have been pretty much the same.
00:37:22
Speaker
right And we're not talking about immediate loading or anything like that, which is another ordeal. Thank you for saying that. That's another ordeal. Very good. Thank you. and And on the other side of the spectrum, how long is too long to wait for us to take advantage of the benefits of these rich preservation up procedures that we're doing? Raise your hand if you've been a ah dentist who did an extraction rich preservation asked Mrs. Jones to come back in four months for the placement, called to make the appointment, and she says, Dr. Velasquez, I can't do that. um ah My insurance year is over. ah My husband is sick, et cetera, et cetera. Or here's one, because this is what happened in our study. COVID hit. Oh. So we specifically decided to do a study looking at extraction and ridge preservation using the 70-30 mineralized to de-mineralized combination.
00:38:18
Speaker
And we were going to do the test group had their implants placed at 12 months. And the control group was the four month time period we'd always been using. so So first of all, getting patients to wait a year to be in that study arm is not easy, but we were able to do it. And interestingly, we had done just a few of the patients in this study and we got shut down due to COVID. So all of a sudden this idea we had had well before COVID, because you may have to do all the IRB papers all months ahead of time, all of a sudden becomes really clinically relevant.
00:38:52
Speaker
And so we were able to do we were able to finish that study on time ah to after you know after we all came back from from COVID crazy. And what we found was from a clinical standpoint. So here's the first question. How long does ridge preservation last? right That's not very scientific. But if we don't put an implant in and get some micro movement in that bone, are we just going to have this nice ridge that's preserved all of a sudden kind of shrink in dimension?
00:39:19
Speaker
right Right, we didn't find that. Hunter Allen who practices in Dallas, she did all the clinical and radiographic part of this big study and we found really the ridge ah dimensions at four months in the four month group were similar to the ridge dimensions in the 12 month group. So that gives me some comfort when my patient says I can't do it right now. When we looked at the histologic outcomes which was done by Jake Zellner in Tallahassee now,
00:39:45
Speaker
um And to see how much vital bone and residual graft did we did we have, well, what would you guess would happen? We had a lot more vital bone at 12 months than we did at 4 months. And we had a a lot less residual graft at 12 months compared to 4 months.
00:40:00
Speaker
But then we did something that that I was really glad we decided to do because we found that on average, even at 12 months, there was still a small percentage of residual graft in those patients, less than there was at the four month group, but it was still there. go there so So Dr. Bowers, you may remember, used to say,
00:40:21
Speaker
in in periodontal defects, we asked him, when I was a resident, he came down a couple of times. And and we asked him, you know how long does that DFDBA that you put in a periodontal defect, how long does it stay there? And he had he had data from a year, which showed they still had residual graph particles. And he used to say, I think it takes two years or longer. Not with data, but you know he's a very well-informed opinion, obviously. So what we showed in our study when we did the the frequency distribution was we had about um In the 12-month group, we looked at this. How many, what percentage of the sites had 30% or more residual graft? At the, in the four-week group versus the 12, four-month group versus the 12-month group.
00:41:05
Speaker
And what we found was that, that we had, uh, uh, in the, in the 12 month group, only 18% of those sites had 30% or more residual graft. The rest of them that had residual graft was, was smaller than that, but 40%, 40% of the four month group had 30% or more of the volume still as residual graft. So here's my conclusion of what if we have to wait to a longer than we want to wait. You're okay. Clinically.
00:41:34
Speaker
You'll get more residual bone if you have to wait 12 months. you'll have or um You'll get more vital bone if you have to wait 12 months. You'll have less
Clinical Concerns with Residual Graft Particles
00:41:44
Speaker
residual graft if you have to wait 12 months, but you will still have residual graft if you have to wait 12 months because it's not all gone by that time period, at least with the 70-30 combination of mineralized and demineralized.
00:41:59
Speaker
Fantastic. Thank you for that answer. It's very, very relevant. And again, every time this we discuss this, the longevity of these particles, of these graph particles, um what would be the cons? We always talk about, yes, they're still there. What would be the disadvantages of having some of these particles remaining at the time of implant placement? Any concerns, any clinical concerns that we should be aware of?
00:42:25
Speaker
Given that you know we're going to place a dental implant kind of right in the center, or let's just say right in the center where that ridge preservation was done, we can rest assured, ah with certainly with xenographs, but even with allographs, that we're going to be we're goingnna have non-vital allograft or xenograft particles in contact with that implant surface. And there's plenty of animal data that show that that happens. But those animal data also show that you get ossu-integration along the implant surface because the the the bone particle is not attached to the implant. You know what I'm saying? There's a space there. So you do get new bone formation between the implant surface and the residual graft particle. But clinically, I know ah Diego, you and I have seen this. We have friends who've seen this. We place an implant.
00:43:14
Speaker
And, you know, a year, two years later, we start to see some radiographic bone loss. Maybe now we have some perian plantitis. We reflect a flap and right at the crest, right at the where that bone resorption has occurred, we see residual graft particles. And so you start wondering, holy cow, you know, that's not good. So so I think that's a concern. right Let's keep in mind.
00:43:38
Speaker
of the thousands of implants that you've done, Dr. Velasquez, how many times have you seen residual parti-, first of all, how many times you get peri-implantitis? And secondly, how many times have you seen residual graft particles right at the crest of that resort bone, bone level?
00:43:55
Speaker
You've seen some,
Xenograft Comparisons
00:43:56
Speaker
haven't you? Absolutely. Out of the thousands that you've done, how many have you seen? We freak out about the two that we've seen. So I think we just have to be careful about that. It's a potential risk, but I don't i don't know that it's it's and i don't know it's enough to make me say, I'm not going to use that product any or that type of graft anymore. It's kind of the sclerotic bone concept you know that some of the particles that are in that allograft will never resort.
00:44:23
Speaker
They never become vital bone. They just kind of sit there. OK, I don't mind that if it's at the apex of the implant or if it's in the middle of the implant. It's when it's up near the most coronal portion of the implant where we may get some bone resorption due to period implantitis that those particles can become exposed and then ah increase the amount of bone loss because now it's just a dead particle sitting there. So I think it's a risk. But I think that the frequency of the risk is relatively low.
00:44:53
Speaker
Yeah, that would be important to keep in mind that that would be the most vulnerable part of exposure that can lead to some issues with protein plantitis. Very good point. Right. Moving on to another part of your research ah as well that is very relevant. When it comes to xenografts, Brian, what would be your recommendation as far as origin? Do you have any preferences recommending perhaps the bovine source versus the porcine source for your your xenograft? And what are your thoughts about that?
00:45:20
Speaker
um the Of course, the bovine zenograph has kind of been out for a long, long time. And when the porcine zenograph started to kind of hit the US market, ah we did a study specifically to look at that question you just asked. Is there ah is there a difference in these histomorphometric outcomes using a bovine and a porcine zenograph that have fairly similar structure? You know what I mean?
00:45:43
Speaker
um So the particles don't look radically different. We did not find any significant difference between the vital bone and residual graft that we had ah in that 18 to 20 week healing time period. Veronica Lye did that study.
00:46:00
Speaker
and over in North Carolina now. And so that made me feel pretty comfortable. So at least for this one study again, be careful making conclusions, but it didn't seem to make a big impact in this ah ridge preservation model. I think it's a matter of personal preference, honestly. That's valid. Thank you.
Experience with Alloplastic Materials
00:46:20
Speaker
Appreciate that. What are your your thoughts and what is your experience with alloplastic materials?
00:46:26
Speaker
ah Negligible. um but We did two studies of our group of however many we've done now. ah We did two two studies that used alloplastic materials, one of which is an orthopedic product, no longer on the on the dental market, unfortunately, because it had the it had the highest percentage of vital bone of any product I've ever used. and it was ah It was an alginine and hydroxyapatite Product worked very well, and then we did another one. That's I don't want to mention any specific names, but we did another one
00:46:59
Speaker
and that also got very good outcomes. But honestly, I guess I've been an out, it's because of Dr. Melanik. I mean, you know, he taught me too. I've been such an allograft person for so long. We tried to limit ourselves to that, that particular type of graft for a lot of the studies until we finally did branch out into xenographs and a couple of alloplasts. So I can't give an informed ah conclusion on alloplasts.
00:47:26
Speaker
First of all, Diego, you know, there there's a million different kinds of alloplasts you can use. Calcium faucet, calcium carbonate, you know, et cetera. I don't think any of those are bad. Honestly, for ridge dimensional change, this is kind of a conclusion for what should I put in the hole. For ridge dimensional stability, we have not found a significant clinical dimensional stability difference between any of the products we've used.
00:47:51
Speaker
ah Calcium sulfate, use simple plaster of Paris. That works great. right um So I suspect that a lot of the alloplasts probably give you very good clinical outcomes. I just
Advice for Young Researchers
00:48:03
Speaker
haven't seen a lot of, I haven't seen a lot of histomorphometrics for some of the, for example, the plugs that are out on the market right now. There's a lot of plugs because they're really easy to use. right But go try to find wound healing data and it's going to be sparse. Correct. I share that same impression.
00:48:22
Speaker
Now, starting to wrap things up, I had a ah question for you. Let's say we have a young researcher, a young clinician listening to this podcast. What would be your advice as far as how to advance this collective knowledge when it comes to rich preservation, if they're doing some research? What would be the next frontier? What should they be looking for at this point? I think there's two two potential answers to that. One would be a more basic science or or you know, kind of a translational science idea. And that's to do histomorphometry for what growth factors are operant when we place when we do ridge preservation. Is there any difference in the protein cascade that occurs in wound healing with ridge preservation versus no ridge preservation? In other words, natural healing. From a more clinical standpoint,
00:49:16
Speaker
ah I would love to see a lot of studies with the growth factors that we're currently using in periodontal and site development, let's say in sinus augmentations, to see good randomized control trials of some of those growth factors with some of the allografts, xenographs, alloplasts that we use for ridge preservation in a combination. So is there any value in adding a a growth factor to, let's say, demonized free stripe bone, for example, versus just the demonized free stripe bone alone. There are some data, as you know, right out there looking at that, ah but I'd like to see large
00:49:58
Speaker
ah randomized controlled trials, maybe that are unfunded, that's that's not fair. But you know what I'm saying. Of course. Very objective ah stuff. And I think you're involved in multi-center trials, you know, in in in places like that is what we need. So you guys
Objective of Ridge Preservation
00:50:14
Speaker
need to do that. I'll pass the message along. Thank you again.
00:50:20
Speaker
One last question actually there's one more question but that just to finish I like to treat my patients in my chair in my office the same way that I would like to be treated or the same way that I would love to treat my wife my daughter my my children.
00:50:35
Speaker
Patients ask me sometimes that question, doctor, what would you put in your mouth if you needed this type of procedure? And that is the question that I had for you that I had saved for the end. If, let's say, God forbid, you were to need one of these procedures, what would you be your request for your clinician that is going to be treating you? What type of material, biomaterial would you like to have utilized in your mouth? I think if I was, um if it was in my mouth, I think my first choice would be 100% demineralized freeze-dried bone.
00:51:05
Speaker
um because I know what that does. and But if i had if if you if you you're doing the surgery on me now, Diego, so I say, okay, I want 100% DFTBA, and you say, yeah, but this really great restorative dentist I work with doesn't like that radiographic appearance. I think the 70-30 combination has been a really good compromise for that. I use it a lot in my patients. So that's probably what I would that's what i would recommend.
00:51:38
Speaker
Oh, and one last thing. If for some reason I had to have my implant like two and a half months from now, I would definitely use the 100% de-mineralized. Fantastic. Thank you. Appreciate that candid answer. I appreciate that. And one last thing, truly now the last question. Is there anything else that you would like to share, Brian, that we didn't ask you? Is there something that we missed during this ah this presentation?
00:52:03
Speaker
I guess, you know, for me in closing, ah with the residents and and sometimes with patients, I kind of want them to understand what is the goal of richs bridge Ridge preservation. You know, we do that so much. We do the procedure so much. And then sometimes I think we lose sight of what the goal is. So if I take a tooth out and do nothing at the socket,
00:52:24
Speaker
What two things do I know are going to happen? Number one is I'm going to get vital bone in that socket. There's lots of good studies that show you get, you know, maybe 35 to 45 percent of the volume of that socket is going to be actual vital bone and the rest will just be connective tissue, you know, non-mineralized bone. So that's one thing that's going to happen. Second thing that's going to happen is the ridge is the ridge is going to shrink.
00:52:45
Speaker
So if I take the tooth out and do no ridge preservation, I'm going to get lots of bone and a skinny ridge. So what is the purpose of ridge preservation? It's to keep a wide, tall ridge, maintain ridge, but is preserve the ridge dimension, and while at the same time developing or ending up with a similar amount of vital bone at the site as compared to no ridge preservation.
00:53:12
Speaker
So if I'm going to put something in there and I'm going to go from 35% vital bone with no ridge preservation to 8% with ridge preservation, I haven't achieved achieved that goal, right? So we don't want our ridge preservation protocol to decrease the amount of vital bone formation that we get in the socket, right? So that that to me is the end result of ridge preservation, the goal. Maintain the ridge dimension while obtaining the same amount of vital bone that you would have had at the site had you not done ridge preservation. Fantastic.
Conclusion and Appreciation
00:53:42
Speaker
Thank you so much. It's been... Can you believe it? It's a little longer than 15 minutes. It's been... it Sorry. You buy. I talk too much. No, this is fantastic. You buy. I just wanted to personally thank you so much for your contributions. Ever since I started following your work, your line of work,
00:54:01
Speaker
I admire the relevancy of your work. You're doing stuff that is practical. As clinicians, we appreciate that because it is information that we can translate it immediately to our patient care. And it is very valid the way you've been presenting this. Number one, thank you so much for having put this paper together. That is, of course, the ah ah a lot of work went was went behind this. I appreciate you giving credit to those co-workers that made this possible, of course, because this is not only Dr. Milia alone doing this, yeah As we know, there is a lot of people involved that made this happen, and I'm very appreciative of you giving credit to them. And again, thank you for having considered clinical advances in periodontics to publish this paper, which I believe is a must-read for the residents. And again, thank you for having done that. um With that said, Dr. Milley, it's been a pleasure. Thank you so much for your time, and I hope you enjoy the rest of your day. And thank you for for agreeing to do this with us.
00:54:57
Speaker
Thank you, Dr. Velazquez. I'm honored that you asked. Thank you, sir. Thank you for joining our episodes today. If you like this episode, share it with a friend. Don't forget to subscribe to the podcast wherever you're listening so you get the latest episodes.