Anterior Open Bites: Causes, When to Refer and When to Treat: A podcast conversation between Dr Chang and Dr Tay (for dentists)

February 25th, 2020 Andrew Chang

This is a blog podcast for general dentists to increase their understanding about a certain bite condition ie: front teeth anterior open bites and how the timing of their referral can make a difference to the quality of care and outcomes their patient receives.

What do you currently say to child, teen or adult patients with anterior open bites? If the patient is not in pain, how would this affect your recommendations?

Have you wondered how the age of your patients can affect the simpleness or complex-ness of orthodontic treatment methods?

Do you wonder if referring them when they are a child, a teen or an adult makes a difference to their smile outcomes, cost and duration of treatment?

While every patient is an individual, and managed as such, this podcast outlines the answers to the above questions. It provides a basis to increase your understanding through identifying:

  1. Different causes of anterior open bites. Early treatment in children is focused on addressing causes ie: habits and skeletal discrepancies.
  2. When to treat: start early or start late? And when to tell if face growth is complete.
  3. Treatment methods for anterior open bites  in teens and adults: moving away from jaw surgery.

We hope you find this useful. An outline of the podcast transcript is also below.

Dr Chang: 00:03 Welcome Diane, great to have you back on board.

Dr Tay: 00:09 Very good and happy new year to all our listeners and hope everyone had a nice holiday season.

Dr Chang: 00:15 So what we would like to talk to a dentists here is anterior open bites. What are the causes of open bites? And when’s a good time to for a patient with an anterior open bite to see a dentist and orthodontist. We also touch on briefly about the different types of treatment and how the age of the patient can make a difference.

Dr Tay: 00:51 Absolutely. So a lot of factors to consider. All of us, we want to have a good outcome. So definitely I think it would be a very useful and interesting topic. Andrew, if you talk just a little bit about anterior open bites and what, what to look up for clinically.

Dr Chang: 01:11 Okay. So maybe what we can do is if we can talk about a person’s growth and is this case, I’m talking about a person’s face growth because the teeth fit on the bones. And one of the things to take away, is the last growth of a person’s face to finish is the vertical growth. So I should preface this by saying that there’s three aspects to face growth. One is the transverse in which case the, the distance between the right and left sides, the transverse growth, that’s the first part of the facial growth to finish. And then it’s followed by the sagittal or the front and back growth. What one would call an example of a transverse growth discrepancy would be what we label narrow maxillae or crossbites.

Dr Chang: 02:08 So these crossbites from the point of view of trying to address this from something relatively simple in a child or early teen should be done by the early teens, by ages 12 or 13. After that, there’s a higher chance of unfavorable outcome. An example of a front and back skeletal discrepancy is the class three. And the last part is what we call a long face or what we call an increased vertical dimension. That vertical part is completed last and sometimes that facial growth can continue particularly in males where their growth finishes later than in females, until the age of 21. So coming back to open bites, I suppose what we want to do is talk about open bites in young kids. I know that Diane, this is something that you see quite often, young little kids. What are the causes when you see kids with open bites, and what are the main things that you tend to find associated with these open bites?

Dr Tay: 03:37 So my focusing on the younger children is what I generally see, which is more commonly the younger ones under five years old. It could likely be commonly from say more habits. And which is why part of when we’re doing now at examinations for kids, it’s something I always ask is : does your child has any habits? So even before I’m doing an exam, I’m starting to ask things like, do they suck their thumb or do they suck a dummy? How long have they had it during the day and are they doing it all the time or just to fall asleep and then maybe the dummy comes out, they’re no longer sucking your thumb. Those are commonly, non-nutritive sucking. Also I commonly see a lot of children with special needs or other genetic conditions.

Dr Tay: 04:29 Often times, they can also be associated. So one of the common things, I mean there’s a multitude of genetic syndromes that can result or come in together because of the facial and skeletal proportions as part of their genetic condition. But one common thing I commonly see because I get new referrals for kids is with amelo genesis imperfecta. So if you’re starting to recognize or see a child which has a generalized hypoplasia or hypo mineralization. You notice they’re starting to be a family history of, you know, where the parents, like all the grandparents had always been to the dentist & got crowns on all teeth. You notice siblings having a similar thing. Then I’d be looking at something correlated with anterior open bite. Often times that can come together with AI and is commonly associated with anterior open bites, in the older children. Obviously I’m looking out for their Scolito patterns even looking also what their occlusion is like. But you know, interested to hear what else from your experience in the older children.

Dr Chang: 05:44 So to touch on a point about, thumbsucking: what I’ve seen in my practice is the dental and arch effects of prolonged thumb sucking: after the age of four years old is when it starts to affect the premaxilla. And that’s when the front part of the mouth starts to become more tapered. And associated with that you get proclination on the upper front teeth. We’ve seen that leading to a maxillary constriction where in other words in the posterior region you have a crossbite forming. The other thing I see in kids and lookout for is signs of airway obstruction. So typically one of the things you can ask the parent is, does your child snore when they’re sleeping or sleep with their mouth open?

Dr Chang: 06:48 The other signs may also be bedwetting or teeth grinding . And then when after I touch on the snoring, one of the other things I ask is do they have any allergies? Cause often anyway, airway obstruction may be related to allergies. And the most common one is allergic to dust. So this is where if you have a local ENT working with them because there are some clinics that even bulk-bill for allergy testing as well. And sometimes it may be something very simple like a nasal spray that would help to improve their breathing through their nose as well. But then there has been studies in the past which have found that airway obstruction can lead to a long face and potentially an anterior open bite forming as well.

Dr Chang: 07:55 So the other thing, touching upon what we did mention about growth and facial growth, if there is a narrow upper jaw because that part of the growth tends to be finished first. It has also the potential for greatest improvement if treated early. So that’s why I’m looking from that point of view and really having a conversation with the parent mentioning the treatment approaches if we identify a narrow upper jaw. And I know it’s not really something that is the main theme of our topic today, but that can be one component by correcting that in a young child, in a growing child before the age of 10 or 11 but in girls and if you’re looking to improve the facial growth, you’re looking at treating about eight or seven years of age that has the potential to improve face growth.

Dr Tay: 09:08 I wanted to also expand a little bit cause you did mention about teeth grinding as one of the clinical signs of airway obstruction of potentially a child having obstructive sleep apnea. Parents say: Oh my child grinds to sleep all the time. Like is there any options? Is there something we can do to stop? Because the sound is very distressing for parents. So while not saying that not all kids who grind their teeth has an airway obstruction, it’s an important thing to ask or further expand when someone reports that just to eliminate or pick up because there is some theoretical correlation between teeth grinding and obstructive sleep apnea.

Dr Tay: 10:09 So one of the things I would then expand further is into other signs if possible that you know ie: looking to see whether they’ve got enlarged tonsils. And you know, as dentists we’re in a prime position to refer them directly to an ENT doctor , allergist as well and it’s really important, teeth are a part of the body and looking after that is, you know, really important. On the other hand, if a child just, this is a side step, teeth grinding, I know that’s not the main topic. However, if a child does a lot of grinding it can also just be physiological. So there’s many kids before they get into the permanent dentition, it’s completely physiological and often times we just say just monitoring it because lots of times we know little kids will not tolerate wearing mouthguards as splints. Definitely expand on the topic of teeth grinding another time, but just thought that there was a really good important point to expand in case our listeners was wondering about why teeth grinding was in association with airway obstructions.

Dr Chang: 11:15 Thank you Diane. I would also like to touch on a point where the one of the other causes of airway obstruction and hence anterior open bite is a smaller lower jaw., ie. what we call a skeletal Class II. That can also be one of the causes of snoring and from the point of correcting this and managing this, it’s best to be done before the peak in their pubertal growth spurt. So as a general guide it has been before the age of 11 years old for girls as an average and 13 year old in boys. However, over the last 30 years, girls have been observed and boys too have been observed to reach their peak growth spurt sooner over the past few decades ago.

Dr Chang: 12:13 So if you’re ever in doubt, look at the individual rather than averages and one of the simple ways you can ask is when your child has a school photo, where do they sit in this school photo? Or did they stand in the front row? In middle row or back row, because the tallest ones are usually in the back row, which means their growth would happen rather than 11, their growth would probably may have at 10 if on a back row versus in a front row their growth may happen later. So that gives you some sort of indication about the urgency of timeframe in terms of when to refer to the orthodontist. Yeah. So a few pointers on that. And the other thing also, I think there’s only been much more attention in the literature about snoring and obstructive sleep apnea.

Dr Chang: 13:08 In an adult, it really is a very uncomfortable thing to either have a CPAP machine in what we call continuous air pressure. That’s definitely where they have a mask. And there’s oxygen, which is placed under positive pressure so they can breathe better. Often adults have to sleep semi upright for that to happen. But it is very uncomfortable if you speak to any adult patients who are having CPAP machines. How I frame conversations with parents is another solution would be to use a mandibular advancement splints, which is essentially what we use to treat a small, lower jaws in growing kids. Except the only difference is in a growing kid is that would help to correct that.

Dr Chang: 14:09 And generally even in a short period as three months, but in the adult, it’s a lifetime thing that they have to wear. So there’s only a window of timeframe that you can correct this where it becomes much more challenging and difficult afterwards and parents seem to grasp and understand that. So the other thing with anterior open bites you may have been aware of is tongue posture and tongue function. One of the ways that you would perhaps see that is you would look at signs of large tongue or macroglossia when they can stretch your tongue out and it goes almost all the way to the chin. And there’s another school of thought about perhaps when if there’s no large tongue, but there is a forward tongue position or what you see as a tongue thrust during certain tongue functions ie: drink, swallow and speech, where the tongue thrust between the two front teeth rather than touching behind the upper incisors around the incisive papilla.

Dr Chang: 15:48 So fortunately, most of these where they have abnormal tongue functions tend to be also associated with lisp and which is really the domains of speech therapists. And this is where you should work with your speech therapist to ensure that the any appliances that you’re making would not interfere as such with the speech exercises that the speech therapist is prescribing. Or you may simply have a go through a short period of observation pending the discussion with the speech therapist about the treatment and take photos before and then photos during. So you can see if there’s any changes that the speech is having. But sometimes causes can be multifactorial. So even though there is one, they can be other causes as we already touched on right now, in terms of habits, in terms of tongue, in terms of airway obstruction. One last point is genetics. Of course on seeing like a Mom’s got a long face, and Dad’s got a long face and it’s quite likely that the child would have a long face as well.

Dr Tay: 17:18 Absolutely. Yeah. That’s always a good thing when you’re looking at the family, isn’t it? That was a fantastic summary of the causes and what maybe you can, Andrew, to touch a little bit about some treatments and I guess when more importantly, what do you think of treatment timing? I know it’s pending the cause.

Dr Chang: 18:15 In a child in the mixed dentition it’ll be depending on the cause: If there is a narrow maxilla, & there are crossbites, I’ll be more inclined to suggest an expander. And in this case it will be my preference to be a fixed expander. If it’s something to do with an airway obstruction then I’ll be working with an allergy clinic and ENT , with potentially a functional appliance to correct the smaller, retrusive mandible, in addition to widening the upper jaw. And my preferred approach is a removable twin block with in built upper expansion for that.

Dr Chang: 19:24 The treatment time for that I usually would do for a period about a year for an expander. And similarly for the twin blocks as well. In someone who is a teenager, I’ll be cautious in terms of wanting to know what stage of their growth that they are at. I’ll be more inclined to observe and see by if they are in their mid to late teenage years & one of the things I’ll look at first is finding out if they’re still growing in height.

Dr Chang: 20:32 And lastly is their facial growth. And a way that you can evaluate facial growth once their height stops is by taking a lateral cephalogram and you’ll be taking some measurements of their face height from that and generally if each overlay another lateral cephalogram about a year later, there will be no changes in the vertical face height growth in a vertical face height, then that’s an indication that the vertical face height growth is complete. So I’m more inclined to do that when the amount of open bite is what I call a borderline that’s typically in the range of about four to five millimeters where if it becomes more severe, it can affect my plans and recommendations. And the last thing I want is to a turn around to say, dear parent, you know, we have to completely change course here because of the amount of open bite that we have.

Dr Chang: 21:30 So I think on those same notes here: My general philosophy would be first treat any habits. And habits should be treated early, preferably in their deciduous or mixed dentition. And it can be something very simply as just having a conversation or counseling with a parent: non food rewards have worked well. And then I’m observing, taking some photos to observe and check this open bite and putting them on a recall and checking that. So the theme of these treatments should be based on a more conservative approach first before we recommend any sort of orthodontic appliances. If there’s anything to do with the jaws sizes like a class II or narrow jaw, I do want to treat them early in their mixed dentition, preferably.

Dr Chang: 22:35 Once in the permanent dentition, after diagnosis is established and if there is no family history, and if the child is very self conscious, sometimes I think as we’ve, as our listeners will be able to know it’s important to have this frank and open conversation with the patients and the parents. What are the pros, what are the cons, what are the recent benefits and what may or may not happen? And then discuss that in conjunction with them. I think we’ve covered the issues today that dentists are aware to look for in patients. If ever there’s signs of crossbites or signs of a large overjet in conjunction with an anterior open bite refer them sooner. Any of those habits that they think that they are there, seek guidance from other health professionals. And we’ve talked about some speech therapists and sometimes even teachers: having help from the teachers or the childcare workers. It can also be quite helpful as well

Dr Tay: 24:04 I think you’re absolutely right about the multidisciplinary team approach. And I think there’s a lot of things that in dentistry in general, in healthcare, we really do need to look at that because there’s so many ways that putting it all our assets together can get a better outcome.

Dr Chang: 24:47 And I know dentists are, & can be quite concerned, you know, the front teeth, they don’t meet & how the back teeth will start wearing down. Well, check if there’s signs of progressive teeth wear: Are the cusps worn or do you see shiny and wide & flat occlusal wear facets?. So in a teenager you don’t tend to see heavy teeth wear. More so in an adult, which has an anterior open bite that has been there for a sustained period of time. I do like to touch on treatment trends for adults and late teenagers. They have been recently a trend away from surgery where anterior open bites can be treated actually quite successfully now. Without surgery using either braces, with skeletal anchorage or what we call temporary Anchorage devices or small mini screws. And these are placed under local anesthetic. With very minimal risks compared with jaw surgery. Recent orthodontic publications also have started to suggest removable aligners where more and more mild to moderate cases of anterior open bites are being treated. These function as a removable bite plane so we can intrude the molars. So it has been something where I think if you’re asking me this topic in about a year’s time I mean, they could well be a trend to treat more challenging cases with aligners and possibly the combination of aligners with temporary anchorage devices may even help to be a better alternative compared with braces & temporary anchorage devices. So that’s something to look forward to.

Dr Tay: 26:30 Excellent!

Dr Chang: 26:30 Is there anything else you want to touch on, Diane?

Dr Tay: 26:32 No, I think you’ve covered that really, really nicely. So thanks Andrew. And I feel like I’ve always learned something.

Dr Chang: 26:39 No worries. Well, thank you. Thank you to our listeners. And thank you, Diane for coming. Thank you.