In continuation of my Blog posts,
Today I would like to discuss about narrow upper and lower jaws which lead to an increased overjet and overbite. Most people have a normal number of adult teeth which are 28 in number (32 if you include the wisdom teeth). If all the teeth have to erupt straight then the amount of space for them should equal or be slightly more then the combined widths of each tooth. If the total tooth material of all the 28 teeth is more than the amount of space for them in the jaws this leads to a condition called as crowding where some of the teeth erupt on the inside and some of the teeth are too bucky. The reason for this on many ocassions is lack of space in the upper and lower jaws to accomodate all the teeth.
This could lead to a condition where the overjet ( horizontal overlap of the upper teeth to the lower teeth) and overbite ( vertical overlap of the upper teeth to the lower teeth) could increase. In such situations when you look at the shape of the arches they would be narrow. Narrow upper arches provides an illusion of upper front teeth being too bucky or forward. All it needs is to expand the upper and lower jaws which would then help us to gain space to line up the upper and lower teeth with braces. Extraction of teeth in such cases may be not be indicated if the facial profile is acceptable as teeth would then go back to close the spaces which would eventually lead to the soft tissues to move in making the chin and nose more prominent.
I have illustrated this with a case below where the patient had a very narrow upper arch which made the front teeth to stick out too much, following expansion and braces ( no teeth were extracted) the teeth were lined up perfectly and she had the ideal smile.
Fig 1: Before expander and braces, narrow upper arch with a bucky appearance
Before treatment: Increased overjet because of the crowding and narrow upper arch
Narrow upper arch “V”shape
post treatment after expansion and braces
Normal overjet post treatment
Post treatment, well aligned upper teeth. “U”shaped upper arch