Good morning, everyone. Okay, I’m Irene Hilton. I’m from the San Francisco Department of Public Health, and, also, I’m faculty at the UCSF School of Medicine and School of Dentistry. The objectives for my part of this session today is to talk about so we can understand the effect of maternal oral health on families, learn how periodontal disease is related to birth outcomes, describe why pregnancy provides opportunity to provide oral health interventions for women.
Just a little bit, on my part, talking about periodontal disease. There’s so much information we’re trying to get to. This is going to be really brief. You can see out of all the slides, these for pictures, the one on the upper left hand corner, that’s the healthy one. This isn’t the only sign. When you look inside a woman’s mouth, don’t go straight to the throat, step back a little bit and look at the teeth and the gums. If you see redness, that’s some type of inflammation just like it is in pretty much any part of the body. If you see red gums, that’s definitely a reason why you want to refer a woman for a dental visit. You can show the woman the red gums and encourage them to get that in order to get that treated is one reason why they would want to go to the dentist while they’re pregnant.
To understand the issues and the research about periodontal disease and adverse outcomes, we’ll just talk a little bit, one slide on the process of periodontitis. There’s two types of periodontal disease. One is gingivitis, which is totally reversible, and that’s what happens when you don’t brush and floss for a couple of days. Then, you get back to doing it, and you get a little bit of bleeding. It goes away once you clean everything.
Periodontitis is about the disease process that is a chronic process. In that disease process, toxic products from the bacteria in the gingival crevice, the area between the tooth and the gum, induce an immune modulated response that results in destruction of bone. These are basically Gram-negative, anaerobic species, and this is really a chronic disease process because you get bone loss throughout your whole life. The important part is that it’s an inflammatory process mediated by your own immune system.
So, here’s a representation of that, again. So, you can see how that leads to potential associations with systemic disease because right here there’s the tooth, and right here is the bone level. Right here is junk, all junk and bacteria, and over time, if it’s not cleaned out, these substances produce these fatty acids that circulate throughout the blood steam. This is what initiates in inflammatory response. You can see tumor necrosis factor, interleukins, and prostaglandins. These are the same type of inflammatory mediators that you find, for example, in diabetics and people that have had cardiovascular events. Again, you can see that periodontal bacteria also result in the expression of these mediators in the bloodstream, and that’s why you get all these associations. The inflammatory process is the same in periodontitis like all these other diseases.
That brings us to these researches also that show association. Here’s a quick slide. This is a bang for your buck slide. It has lots of things in it, but basically, what you want to know in relation to periodontal disease and child bearing age is if you look at the prevalence in the population, it’s actually relatively low. Periodontal disease is age-related. So, the older you get, the more chance and more prevalence there will be in the population.
So, for women of childbearing age, when you’re looking at women that have the level of periodontal disease that has been associated with these adverse birth outcomes, it’s a relatively low percentage, but you can see that most women complain of gum bleeding when they’re pregnant. Again, it’s important to have them go to the dentist so that we can do our diagnosis and measurement so we can tell what level of periodontal disease we’re talking about because sometimes in the mouth, it all looks the same. You want to get more diagnostic testing done.
The other thing that you want to be able to see is there’s three bars here, and the one in the middle, the almost lime green bar, is African-American. So, no matter what age group you’re talking about, there’s a higher prevalence of periodontal disease in the African-American population. So, again, there is a disparity in health status which, again, impacts periodontal disease as well as other potentially related conditions.
So, the idea of the association between periodontitis, periodontal disease, and adverse birth outcomes, the earliest research you can see has been almost 15 years. You have case-control and prospective studies that have been done over this time that have shown both association. Both types of studies have shown association, again, depending on the study between low birth weight, pre-term birth weight, or preeclampsia with all the other factors being controlled.
There’s been so many studies that have been done in relation to that that there’s been a meta-analysis of all the analyses that have been down showing association. Again, this meta-analysis, which was done last year in 2011, was 125 studies during the last 12 years. Basically, the outcome of this meta-analysis is there is association between a certain level of periodontal disease and preeclampsia and prematurity.
When you try to cross that bridge between association and direct causation, you have to have a biologically plausible mechanism to explain it, and two of the most common roads that people have thought of in terms of how to explain this possible association is, again, there’s generally two trains of thought. One is that you have periodontal bacteria circulating from the mother’s mouth through the body, and triggers this immune-modulated response, cytokine release and prostaglandin release in the uterus that could potentially be what triggers muscle contraction. The other train of thought is some of the periodontal bacteria and toxins can actually cross the placental barrier and colonize in the fetal-placental unit, and, again, trigger and inflammatory response.
You have several stages that have shown different periodontal-causing bacteria in the amniotic fluid or in stillbirth. For example, one of them, P. gingivalis, is one of the bacteria that’s most responsible for periodontal disease. So, we have these studies showing association. We have some biologically plausible mechanisms, and in the hierarchy of showing causation, you have to go to randomized clinical trial in order to get your causation. When you actually go to the randomized clinical trials, you find that they show, at least the two largest clinical trials, both funded by the National Institute of Health, and we can see was published in the OPT and the New England Journal of Medicine MOTOR and Obstetrics and Gynecology. We can even look at the motor, 1800 subjects, incredible how difficult because very few women have the level of periodontitis associated with the adverse outcomes. To be able to get 1800 and to be able to put them in the treatment arts and all the resources that were expended for this, but both of the studies did not show significant difference, again, between the women that had their periodontal disease treated by scaling and root [22:47] while they were pregnant and the ones that did not.
So, now, we have had even enough intervention studies, again randomized clinical studies, to be able to do a meta-analysis of the clinical trials. In the last two years, 2010 and 2011, there have been three meta-analyses aggregating all of the clinical trials all over the world, not just in the United States, doing interventions, scaling and root planing versus treatment after birth. Again, in the aggregate, they have not shown any effect on the adverse birth outcomes. At the same time, there’s still bench research because we continue to have this association. These researches are what we have up to this point. So, things still continue to go on like I’ve said.
This is an example of a study that was done last week, and this is a bench study showing, again, that this particular bacteria, again, another periodontal bacteria, can induce cell death in placental precursors. So, again, research continues to happen. Hopefully, sometime in the future, it will become clear what the mechanism for adverse birth outcomes is and periodontal disease, if it does play a disease, how does that really work at the biological cell level.
So, what do we know? Again, we know that we have this association. We believe that it’s probably related because we have [24:37] periodontal disease, there’s adverse birth outcomes, has some kind of inflammatory component. What we need to remember is that having gum disease, having periodontal disease in pregnancy is a disease/pathological state, and that restoring a woman, while pregnant, to periodontal health has value in itself regardless of whether or not there is a link with some other types of outcomes, system outcomes for both the woman and child. Again, we want to be healthy in all parameters.
On the flip side, the flip side of all these studies has been that you can see there have been thousands and thousands of women in the United States, all across the world that have had dental treatment done while they were pregnant, and they didn’t have a higher incidence of adverse birth outcomes. So, you can also see that getting treatment, not just periodontal treatment but on some of these studies, there are arms where women were getting routine dental care, fillings and extractions, that also did not have worse birth outcomes through dental treatment. Again, these studies show that it’s obviously safe to do dental work while pregnant.
So, let’s talk a little bit about another disease process that we’re quite, quite clear about, the relationship between maternal status and the status of the child, and that’s dental caries. Dental caries is actually a bacterially modulated disease that once you acquire the cavity-causing bacteria, you basically have to manage this disease risk pretty much throughout the rest of your life. In that way, again, it is acquired in a transmissible fashion, but it’s managed like a chronic disease like diabetes or hypertension or, depending on your lifestyle factors, there’ll be times in your life where you’ll be at a higher risk of having a disease or lower risk of having that disease.
Cavities, what the dentist drills and fills every day, is basically the surgical removal of the end stage of the caries process. Again, dental caries is a multifactorial disease with multiple bacteria associated with it. The most common one are Streptoccus mutans and Streptococcus sobrinus and Lactobacilli. So, then how do we get cavity-causing bacteria? We know now, through years of research, if you look at this, Berkowitz’s research, you can see is 1981 were the first studies showing that the maternal transmission from mom to child is the most common way to acquire Streptococcus mutans. You can have horizontal transmission from kids or even other people, but there’s always the highest fidelity with the mom. Of course, we know this now with DNA sequencing of the Streptococcus mutans bacteria as cavities of mom and child match.
So, here’s some examples of how you get Steptococcus mutans transmission. It’s really pretty common, and we all have levels of Streptococcus mutans in our mouths. It’s just a question of whether we have high or low. Remember, we can’t really avoid transmission, but what you can hope is to slow the rate down or have it be at very, very low levels. All the research shows that women with high counts of Streptococcus mutans, their children will get cavities faster, earlier, more than women with low counts of Streptococcus mutans.