Swords Orthodontics
17 Main St, Swords, Co Dublin, Ireland

Just when you thought your braces were coming off…Spaces! Gaps!

Why are there still gaps between my teeth?
I have been wearing braces for ages, I thought I was getting them off soon?

Well, this was sort of the question I was asked by one of my orthodontic patients from Balbriggan two weeks ago, and it's a great opportunity for a short article to explain a common reason that you might still have space between teeth towards the end of orthodontic treatment and the basic options for solving it.

I have another article on this topic with a list of reasons, but this one is about a specific problem that generally manifests itself towards the end of treatment - a problem with the relative tooth sizes - that is the size of the teeth when compared to each other.

Before I talk about the spaces, I need to explain the basic aim of most orthodontic treatment - a nice smile usually involves straight, well aligned teeth, symmetrically placed and the upper and lower teeth fitting together in a good relationship. The target relationship for most people involves the upper teeth biting outside the lower teeth.

So when something has to fit outside something else the thing on the outside has to be bigger than the thing on the inside*. Even if it's only slightly bigger, it still has to be bigger.

Some non-dental examples:

  1. my watch strap has to be bigger than the outside of my wrist or it won't close
  2. my belt has to be bigger than my waist or it won't close (you can imagine that Homer Simpson has some trouble with this idea)
  3. my shoe has to be bigger than my foot or I can't get my foot in it, or if I can get my foot in it, then I won't be able to lace it up
  4. my bicycle tyre has to be bigger than my bicycle wheel or it won't go on.
  5. A better example might be two rings of people holding hands and dancing around each other. There needs to be more people in the outside ring, or if the number of people is the same in each ring, then the people in the outside ring will need much longer arms!

For teeth, the teeth in each jaw are arranged in a sort-of horseshoe arch shape. Ideally the teeth in each jaw are touching tightly without spaces.

If the teeth in the top jaw aren't big enough to fit around all the lower teeth then either:

  1. there will be spaces between the upper teeth
  2. the teeth won't fit together the ideal way
  3. some combination of the two situations

If the teeth in the top jaw are too big, then there aren't any gaps, but they might stick out a bit more than usual beyond the lower teeth. This is pretty rare, and no one really notices this. Depending on which research you read, this problem with top teeth being too small can affect at least 1 in 6 people, sometimes as many as 1 in 3.

So if the top teeth are too small, and you get them nicely lined up, and in the right positions so that the correct top teeth meet against the corresponding lower teeth you will have gaps somewhere in the top jaw. This is usually at the sides, just behind the upper front teeth. Once the upper front teeth have moved back all the way to touch the lower front teeth, and the other teeth are in their ideal positions you can't really close the gaps by moving the teeth, unless you accept that you'll be moving them to positions that aren't ideal.

So when you get to this stage, you don't have to accept the spaces there are still a few options:

  1. Make the lower teeth a bit narrower - an orthodontist will have special instruments for very slightly reducing the width of teeth very precisely and gently. When the lower teeth are narrower, it's easier for the top teeth to fit around them. The braces close up the space on the lower teeth and reduce or close the space on the upper teeth.
  2. Remove a lower tooth, usually one of the lower front teeth and the braces close up the space on both upper and lower jaw. This option is rarely used.
  3. Make the upper teeth a bit wider - this is usually something that would be arranged with your own general dentist as they would have a bigger range of materials for doing this with good colour match to the original teeth
  4. Accept the spaces - this is actually a common decision among patients, and I've seen movies where some of the actors seemed to do just that: their teeth are straight but have slight spaces at the sides.
  5. Some combination of the above

(In the example of the people dancing in two circles while holding hands, this is the equivalent of the people in the inside ring holding their hands closer together and the people in the outside reaching out as far as they can, or even someone leaving the inner ring and joining the outside one, or some people in the outer circle having to leave go of each other's hands.)

The choices aren't always interchangeable, sometimes teeth are significantly bigger or smaller than normal, and that needs to be dealt with.

We usually can tell this will be a problem early on in the treatment, but many orthodontists wait until the teeth are straight, symmetrical and fitting together well before they make a decision on the extent of the problem, the options and the best course of action.


* This doesn't apply to Dr Who's spaceship, but he takes forever to get an orthodontic appointment with.

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As part of Phase One of the National Reopening, Swords Orthodontics is now resuming routine orthodontic treatment.
There will be a few differences in how we do this specifically to deal with coronavirus, but you'll still be getting great orthodontic treatment.
We'll be in touch to reorganise your appointments, please don't attend without an appointment.