A very common question we get from patients is “Why Are My Teeth on an Angle”? There are two main reasons behind why teeth may be angled forwards or backwards and we thought we would provide some insight.
Let’s first talk about Crowding and Spacing. The space available for teeth and the size of teeth are not correlated at all. Someone can have big jaws and small teeth – which will result in spacing, or small jaws and big teeth – which will result in crowding. Very rarely is the space available and the size of teeth perfectly correlated. If that were the case, orthodontists would be out of business 🙂
Side note – the space available for the teeth and the size of the teeth do not change. After about age 7, once the permanent first molars have erupted, we have an idea what we’re working with. In fact, when the baby second molars exfoliate (usually around the age of 11), the permanent first molars tend to move forwards, reducing the space available to align the front 10 teeth. When severe crowding is anticipated, oftentimes a lower lingual holding arch is recommended as a space maintainer to keep the permanent molars back. The message here is that even though the jaws grow (forward and downward) up until late teenage years, it does not give more space for the teeth.
Crowded teeth need room/space to align. So when we align them with braces or Invisalign, two things happen – the teeth move outwards and forwards. In general, however, most of this is expressed by forward movement of the teeth and this causes protrusion. In these situations, the teeth may be angled out quite excessively. Teeth cannot be moved outwards that much as the bone size is fixed and moving them outwards too much leads to gum recession. That is why if you are a candidate, your orthodontist may prescribe a palatal expander. This appliance actually makes the upper jaw wider, creating more bone, so the teeth can be moved outwards (laterally) as opposed to forwards). Extractions and interproximal reduction are other solutions to help reduce the excessive forward angulation of teeth.
Conversely, in situations where there is a lot of extra space, closing all the space can lead to the front teeth angling backwards. In some of these situations, your orthodontist may recommend that you consider getting dental bonding. This is a conservative approach where your dentist will add tooth coloured filling material to the sides of some teeth to make them bigger.
The second main reason that affects the angulation of teeth is jaw position. Most people’s jaws are not perfectly aligned. In situations where the upper jaw is ahead of the lower jaw, an “overbite” usually appears. An “underbite” often occurs in situations where the lower jaw is ahead of the upper jaw. Orthodontists are tasked with making the teeth fit together since the jaw positions are usually fixed and cannot be changed significantly.
How is this done? In an “overbite” the orthodontist is applying a backwards force to the upper teeth and a forwards force to the lower teeth. In these situations the front teeth often appear angled backwards slightly and the lower teeth appear to be angled forwards. The opposite is true for underbites – where the upper teeth appear to be angled forwards and the lower teeth are angled backwards.
Keep in mind there is always a limit to how much the teeth can be moved since they are housed within bone and gums. Moving teeth too far forwards and backwards can have the same effect as moving them too much outwards – gum recession or even tooth loss. In situations where the jaw discrepancies are too large, jaw surgery needs to be considered.
In summary – the angulation of one’s teeth is dependent on a multitude of factors. When crowding is addressed with orthodontics, the tendency is that the front teeth can end up excessively angled forwards. When spacing is addressed with orthodontics, the tendency is that the front teeth can end up excessively angled backwards. In “overbites” the front teeth are more upright compared to “underbites” where the front teeth are angled more forwards.
If you wish to change the angulation on your teeth feel free to contact our Vaughan office or you can even submit photos for a virtual consultation.