You start orthodontic treatment to straighten your crooked front teeth. Once they are in a proper line after a few months of treatment, you may notice dark, triangular empty spaces appearing between some of the teeth. Some patients call them ‘gaps’, yet they are there even when the two neighbouring teeth are in tight contact with each other. The reasons some patients have this problem are:
1. Thin gums – this is a characteristic of the tissue, and unfortunately patients with this type of gum are prone to gum recession;
2. Large teeth with a wide crown and a narrow base at the gum line (triangular-shaped incisors);
3. Some patients who start with very crowded teeth have less bone in this area.
Black triangles can be dealt with by filing down the side surfaces (the contact points) between the teeth concerned and moving the teeth closer together. Sometimes the triangular space is very large and this method cannot eliminate it completely, because too much enamel would have to be filed off the teeth. In these cases it is better to have bonding on the two neighbouring teeth (adding material) to fill the gap.
This answer is for general information. Your own case needs an examination by an orthodontist.