Supernumeries- Identifying them and managing unerupted supernumeraries in the front maxilla

How considerations and the management plan differ in children, teenagers and adults. A podcast between orthodontist Dr Andrew Chang and pediatric dentist Dr Diane Tay that covers the issues in detail.  

Dr.Andrew Chang: 00:04 Diane, welcome, it's nice to have you back on our podcast.

Dr. Diane Tay: 00:08 Hi Andrew. Very good to chat to you again. As always.

Dr.Andrew Chang: 00:12 Well, what we'd like to talk to our audience of dentists today and if there is any interested parents out there as well, but mainly for dentists. The topic of supernumeraries or what we call,extra teeth types. And we were going to focus on the area of the upper front maxilla, the upper front teeth region. So maybe Diane, if you could provide our audience an outline of the different classifications or types of uninterrupted supernumeraries that we're going to talk about.

Dr. Diane Tay: 00:50 Yeah, absolutely Andrew, thank you. And yes, you are right for the benefit of the audiences. We know there's many different types of supernumeraries they can be in different positions, different numbers. And so just to clarify to be, particularly, you know, a really interesting topic and there's so much to say about that, but we're just going to limit it to unerupted teeth and anterior maxilla, which is something really common and has an impact. And I think can be reasonably,picked out and you know, and noticed and managed early by dentists. So as we were saying, souvenir is basically it's just a type of dental normally in the numeric form in terms of the number. So there are different types of supernumeraries and generally overall we divide them into what we call supplemental tooth or supervisor supplemental tooth is where it actually has the exact same form, the exact same function as adjacency.

Dr. Diane Tay: 01:49 So they pretty much don't really have any difference in anatomical differences versus supernumerary. More so where is the tooth? It's characterized by an atypical anatomic form and sometimes they can be smaller or different in the anatomy, very very briefly and a very old classification. You can classify them into the more conical shape form, you can classify them as tuberculate or supplemental form. So it's just a different sort of classification depending on the roots. Obviously there's other kinds of which I won't go into, such as composite odontomes etc. But really important to look at them and also determine the position. So it's not just what type of supernumerary it is, but the position of the supernumerary. So sometimes they can be just in a normal position they could be inverted.

Dr. Diane Tay: 02:42 So those ones tend to, and we'll talk about them more but inverted do generally and very rarely they don't erupt by itself. So hence sometimes the management does become different. And being aware that generally these ones will not erupt. We need to decide whether we need to remove them pending other things, which Andrew and I will discuss, just to clarify for a lot of our dentists, because we hear commonly misused terms, but strictly speaking, mesiodens is a tooth that's located between the central upper incisors. So a supernumerary say, you know, how little or to the 11. So that would not necessarily classify as a mesiodens. So it means it's actually one that's located between the upper incisors.

Dr. Diane Tay: 03:33 But I guess most irrelevant in classifications. While important, I guess like you and I, Andrew are very interested in the clinical management. So what are some of the signs that are important to know? And I know from my point of view, I always think the picking up, sort of knowing our, again going all where I was going back to first principles, knowing our dental development, knowing when teeth erupt, when should they exfoliate, always will help us lead to picking up these things early. And again, the earlier these things are picked up, then management always becomes, easier, less complicated. So the first thing I always think about when I'm looking at a patient is this dentition appropriate for their age? And so if you notice that there's somewhat of a delay or a failure of eruption in the permanent incisors.

Dr. Diane Tay: 04:22 So let's say a patient is eight years old and they've lost the lower incisors, the upper incisors, there's absolutely no mobility in the central incisors. Or even if you may see asymmetrical eruption. So, for instance, you may see the 51 has exfoliated and the 61 is still absolutely no signs of mobility, clinical mobility. I would be starting to look into reasons as to why. There is a failure of exfoliation and failure of eruption, of the permanent incisors. Also of course I know is different, but maybe there's an extra tooth in the sequence so you may notice that there may be a supplemental 52. So again, counting the teeth and charting them properly. But another thing that really, is important also if you start noticing a large gap or a diastema between the two front central incisors, often times people tend to think, Oh look there, that must be caused by a labial frenum. And that may be the case. But for me, I always will check if there is, if I'm concerned, it's just taking a very, very simple radiograph and you might find something else that may be present there. I mean, Andrew id be really happy to hear from your perspective or clinical experience of what you think or is there any other clinical signs that you might

Dr.Andrew Chang: 05:41 I've definitely seen your two, the two most common ones that in my experience has been the large gap, between the front central incisors where one incisor has erupted and the other incisor has not formed. So I suppose this leads to the next question is what other, you did mention a periapical, but what other diagnostic age should a dentistfirst of all use to diagnose this?

Dr. Diane Tay: 06:17 Yeah, that's a really good question, Andrew. From my side of things, I guess coming from a surgical standpoint where I'm starting to think, okay, how am I going to manage this. This for me, first of all, it requires management, what do we need to do? We have to remove it. Can we wait? Can we watch and see? So I guess a simple thing which all of us in clinical practice can do to start with is a periapical you could, and I know a lot of us practitioners do have our own OPG machine, which you can do to get an overall view. However, the only thing I would probably suggest is to get a cone beam scan and again a lot of practitioners I know have their own cone beam machine. The benefit or the value of a cone beam x-ray, sorry, a cone beam scan is that it also acts as a surgical means to localize the tooth and guide surgery planning.

Dr. Diane Tay: 07:06 So from a surgical standpoint if I'm going in, it's good to know exactly where the tooth is and also relative, obviously how much with bone is overlying it where to position it, how easy to retrieve it, what the proximity to adjacent structures adjacent developing permanency. So these are all really important to decide on a really separate known because I do have a really keen interest in that other, you know, other in children, managing kids with medical comorbidities and certain syndromes. I think it's also relevant and important to just consider if you do take an X-Ray and you see multiple supernumerary that you have to stop thinking of other systemic causes such as Gardner's syndrome, or cleidocranial dysplasia. I know those things tend to exhibit other signs as well. However, it's just valuable to start thinking about things. And that was just a really side comment I thought I'd make off the top of my head.

Dr.Andrew Chang: 08:04 Yes, yes. All clinical clinician. And I think I do recall with an opg, if it's outside the focal trough and there's multiple supernumeraries, that may not necessarily pick that up. Is that correct?

Dr. Diane Tay: 08:19 Yeah thats right. So, which is why I think a periapical is used if you're concerned that there may be another, you can always do that simple SLOB rule, have a look in and do a few angles to get, but I guess a cone beam CT, which is very easily obtainable these days,and the radiation is very low and comparable now. It's a worthwhile x-ray or diagnostic film to get so you can also use it for your surgical planning as well.

Dr.Andrew Chang: 08:48 So to recap for dentists, if you suspect there's a supernumerary, i.e as in you see a large gap between their front teeth or delayed eruption, you would take a screening, a x-ray like a periapical. And if one is considering in terms of the surgical management or in terms of how do we go about approaching this orthodontically then it would definitely need a CT. From my perspective and what I look at, I definitely require a CT to locate the tooth, so we can see in terms of is it close proximity to the developing adult teeth. Let's say if it's the upper central incisors, which may not be able to erupt because there's an impediment with the supernumerary and the permanent central incisors from erupting. I would want to make an assessment, well what is it's proximity because that would be an indication of what are the risks associated with the exposures in terms of with the surgeon accessing that area. And also in terms of moving that central incisor down. Having a CT provides three dimensional information that it goes far beyond what an OPG can provide.

Dr. Diane Tay: 10:08 I think cone beams are definitely coming up in terms of not being diagnostic and clinical management.

Dr.Andrew Chang: 10:16 So I suppose it now leads into the you did raise an important point. One of the things that you had talked about with the classification, these uninterrupted supernumeraries is that they often atypical as in, does that mean that the crown is usually not like a normal size is usually perhaps smaller or a a funny shape perhaps?

Dr. Diane Tay: 10:41 Yeah. In my experience, usually the unerupted supernumerary tend to be very, they have a very clinical form, the smaller and oftentimes when they're inverted, as I said, they don't actually, they won't erupt until, I guess it is. I tend to advise parents that these are probably the ones that will need to be removed. But again, that goes into looking at what other factors to consider.

Dr.Andrew Chang: 11:09 I suppose this is now a segue into this topic. So we've located the Supernumerary. What are the implications of having a supernumerary and what happens if we don't do anything? What may happen?

Dr. Diane Tay: 11:26 Because parents do want to know, they want to understand, do we often question is really do I need to remove this as is not causing a problem or my child has not complained. What do I need to know? When should I look at managing it? I think the important thing with supernumeraries is because generally of where they are located, they can or tend to cause failure of eruption in incisors, eruption of the permanent and you know, usually the central incisors and sometimes they can also cause ectopic positioning and movement of the permanent teeth or displacement in some way of, of adjacent teeth. And sometimes I've also seen supernumeraries that do not impede the eruption of the permanent teeth.

Dr. Diane Tay: 12:17 And parents say the permanent teeth are coming out. Do I really need to remove the supernumeraries cause it's clearly not blocking the way. However, you also have to consider from an orthodontic, and obviously we value your opinion but from an orthodontic perspective, can supernumeraries interfere with orthodontic teeth movements? And that's where, for me, I always tend to work with orthodontists to treatment plan these things. And I think you and I, Andrew had worked in a few cases very successfully together.

Dr.Andrew Chang: 12:53 I have. So I should talk about in terms of three patients I can recall on this one was that we collaborated on where the supernumerary or that extra tooth was what we call incisal to the adult developing adult front tooth. So it was clearly in the path of the erupting tooth. And,fortunately one of the things is we got to that early. Generally, If the root of the adult front tooth has fully formed, there's a lesser chance of it wanting to erupt by itself. So it becomes a balance of well, do we go in soon knowing that the root of the front tooth has not fully developed, possibly it may be risking its root development by doing this surgical exposure, or do we wait and let the root form a bit longer and then do we expose it,remove the supernumerary and expose the tooth at the same time.

Dr.Andrew Chang: 14:04 So generally, we normally would like to have at least half to two thirds root formation on that central incisor before I go in, as I don't want to make a surgical intervention too early, in terms of removing that supernumerary,if I felt that there was a high risk of interfering with development of the upper central incisor root.

Dr.Andrew Chang: 14:30 In another case where we collaborated. In this case, the girl was a bit older. She was about, 9 if i recall. So,the root was literally almost fully formed. So in this case we made a decision to remove the supernumerary and expose the central incisor at the same time. There was another instance where I saw another patient who was a slightly younger and we clearly had enough space for the adult, cetral incisor that to come down. And I can't exactly recall, it may have been a mesiodens right in between or may have been a supernumerary. But in that instance she had the mesiodens removed and the central incisor erupted without orthodontic intervention.

Dr.Andrew Chang: 15:24 And the last patient that I can recall quite clearly is an adult where the supernumerary in this case it's probably a mesiodens where it was right in between the two front teeth. It was actually located incisal to the upper permanent incisor. So the tooth was inverted and was conical in shape exactly what you described. And it was actually right below the nasal floor. So being an adult, she's very wary of having that removed, so the consideration for orthodontics is would its presence interfere with the zones of movement or the boundaries of movement of the teeth.

Dr.Andrew Chang: 16:06 And in this case we took a cone beam CT & we've verified that supernumerary was actually quite high superiorly and along the palatal aspect and we determined that at that point in time we would be monitoring with another CT in 12 months time, and as you may understand she was very hesitant about having the supernumerary removed. So we went through a discussion of the risks and benefits, the pros and cons,but because it was quite high up, d after running through that with her, e made a decision together to review that in 12 months time with another cone beam CT.

Dr. Diane Tay: 16:42 Yeah i think that explains things really well. You have a really good point about all of them.

Dr.Andrew Chang: 16:50 I mean there's one other thing in terms of implications of having an extra supernumerary is sometimes leaving it too long can lead to displacement, not just of the central, but it can also lead to displacement of the lateral incisor, which may be impeded in its eruption. So depending on where that location of that supernumerary is keeping it in there, f it's located incisal to the adult upper incisors is probably not something I would do, indefinitely, ue to the effects on eruption of the adjacent teeth there. Definitely, if you're going to monitor that, it will need closely monitoring and at some point you need to make a decision to have that supernumerary removed. And working in conjunction with in this case a surgeon or a pediatric dentist and an orthodontist is definitely very helpful as a team effort.

Dr. Diane Tay: 17:55 Absolutely. No, Andrew, I think your cases really classify and very well illustrate what we were looking at and talking about before. So what are important things to consider when we're managing supernumeraries because identifying it is easy, but what are you looking at when you're thinking about how to manage it? So, I mean from my perspective as you correctly saying you illustrated it again, you know, across your cases, the age of the patients shouldn't just be a guide, because we're looking at the root development stage of the permanent incisors. So you're weighing up the risk benefits of surgery of damaging developing permanent teeth & waiting too long and impeding or preventing the spontaneous eruption of the permanent incisors.

Dr. Diane Tay: 18:43 You also have to think and consider as we discussed, the number of supernumeraries, the position, where is it, is it inverted, what type of supernumeraries and which is why we say use the cone beam to determine exactly, the locality and the position and, and proximity to adjacent teeth, we have to consider which tooth is it around, is it an erupted supernumerary or unerupted supernumerary? And also what are the parents' expectations? What's the occlusion like? Is this, you know, is this child likely to require orthodontic movement of teeth so is it something, can you leave it or monitor it. So is the supernumerary actually causing ectopic or displacement of the permanent teeth? In which case then you may need to consider,acting and being more proactive in your approach. Those are some of the things I'll be be thinking about. Was there any other points, Andrew, that you'd like to get from your clinical experience?

Dr.Andrew Chang: 19:52 I think if we had to list out the factors which we covered on, all we touched on. One was the, the age of the patient. We talked about in a child, we also talked about it as an adult. As we talked about it, I can recall a teenage patient who also had a supernumerary where he was in his permanent dentition and he was about 13 or 14, and most of the supernumeraries that I've had in the anterior maxilla tend to be slightly along the Palatal. And I can recall because this patient, while he had crowded teeth but his upper front teeth were also,proclined as well. And when the mum went to see the surgeon because of where the supernumerary was, it was located apical but close to the apices of the permanent central incisors.

Dr.Andrew Chang: 20:42 But because the surgeon mentioned there is a risk of the upper front teeth losing their vitality or nerve, and in case what it means by that if there's any parents listening to this, is that nerve could suffer and a tooth may die or darken, in which case he may require a root canal, as a complication of surgery to remove the supernumerary tooth. But because of that risk, the possibility of that risk, they held off removing this supernumerary. And because the supernumerary was lying more a bit more palatal, we could not bring his upper front teeth back. So we kept them at a forward inclination. In other words, the upper front was sloping forward. So while his teeth were crowded, we straightened them. We didn't really bring them back but of course, then we came to a point where I said, well, we can't move it back. She wasn't happy with the current smile either.

Dr.Andrew Chang: 21:31 So at the end she made a decision, yes, the risks, but based on what the surgeon said, the risk was actually very small. So she went back to the surgeon and found out the risk was actually very small. So then she said, well I made a decision, I mean it's a balance of benefits versus risks. Okay, we'll have that supernumerary out,and turn out in the end the upper central incisors were fine, the vitality was fine and we managed to move the upper adult front teeth back and correct the protrusion and he is very close now to getting his braces off. So it's a balance of where, when we talk about for teenage patients, it's more getting the orthodontist involved and in terms of where the movements of their adult teeth are going to go and would the presence of the supernumerary interfere with them getting an ideal treatment outcome in terms of their smile & orthodontic correction for teenage patients.

Dr.Andrew Chang: 22:29 That's a main consideration for the adults of course there's often may be other medical histories that may affect in terms of surgical risk, and would involve maybe a closer conversation with the oral surgeon. Often adults,need to be more aware of the situation and they tend to be less inclined doing invasive surgery,particularly if its quite high. If a decision is made to keep a supernumerary, close monitoring is important and if the patient goes and for some reason doesn't come back, they need to be aware of that, that a supernumerary needs to be monitored because in a very, very small number of cases there can be cases of cysts. I mean the possibility is very small. It's just something that the patient needs to be aware about.

Dr.Andrew Chang: 23:38 So is there any other important factors I suppose to consider if we had to list it out, we've already covered root development, child, teen and adult management, is this a permanent incisor or primary incisor? Is the supernumerary erupted or non erupted? I suppose the good thing is nowadays with a CT you can easily see the shape and the size and the widths of the supernumerary. Some supernumeraries are generally smaller in size as we touched on. Very briefly and I know this is not really the topic on this podcast it becomes a bit harder when it's a supplemental, when a tooth is already erupted and is quite close in shape to the other incisors.

Dr.Andrew Chang: 24:33 One of the things that I'm inclined to look at is the width, but also the root formation and because sometimes some supernumeraries may have dilacerations in terms of root or dens in dente associated with them. So there's something that I'll be looking at quite closely, in terms of their pulpal status, but the main decision is which tooth could look nicer, both on the clinical point of view or aesthetic point of view and has got a good pulpal health as well. The other consideration for important factors is root development stage. And I know we touched on the risk of surgery and the position of the adult incisors, is a supernumerary causing displacement of the other incisors , patient factors: cooperation and the parent factors as well. Is there anything you want to elaborate on Diane?

Dr. Diane Tay: 25:34 No. Covered points very, very thoroughly and exactly what you're saying with looking out for these things. I think that's a key to success and management of the case.

Dr.Andrew Chang: 25:48 We've touched on these management options earlier by talking about these case studies, but could you briefly outline the management options if you haven't covered any of it?

Dr. Diane Tay: 26:05 We pretty much covered it through our discussion on the cases. But I guess to just really summarize it, mainly first if the option is to monitor, say maybe because the child's only three or four younger, we're waiting to decide what we're going to do or versus if the patient's older to say, then monitoring closely, ensuring you get appropriate radiographs just to manage monitoring for any specific changes such as cone beams would be very good and very clear x-rays or scans. So sometimes it may just involve simple surgical extractions.

Dr. Diane Tay: 27:01 And then let's say the child is six, six and a half, seven, and we know this, a supernumerary that's impeding the eruption of the permanent incisor and you have an over retained say 51 or 61. So you'd want to remove the primary incisor as well as the supernumerary and then monitor the eruption of the permanent incisors. So this would obviously be, and I often at times in the cases I've done before, work together with the orthodontist to determine and finalize the treatment plan: So if I'm going in surgically knowing whether we're just going to monitor the incisor based on the root development as you correctly say Andrew, we're looking at the root development if its about half to a third of roots.

Dr. Diane Tay: 27:57 However, conversely, if the roots, let's say this has been picked up and now the child is 10 or 11 years old and the root of the permanent incisors have already formed, then sometimes what we'll need to do is in addition to removing the supernumerary and the retained primary incisor, then we would really would be looking at doing a surgical exposure and potential bonding of the tooth orthodontically, to bring the tooth down into the arch. Oftentimes I get them to see the orthodontist first to lay down those braces archwires. And prior to surgery, was there anything else Andrew you'd like to add to that?

Dr.Andrew Chang: 28:47 I think we covered that really well. And it's really nice to have you on Diane and I hope the audience took something away today.

Dr. Diane Tay: 28:58 And thank you so much for listening again, and we will have more interesting topics to discuss next time. Thank you.