The incisor teeth are at the front of the mouth and have a flat edge designed for shearing or cutting.

Incisors are usually bigger in herbivores (plant eaters) and omnivores (plant and meat eaters) because they are useful for biting off pieces of plant-based foods before chewing them with the back teeth. Carnivores (meat eaters) have relatively small incisors because they use their more pointed canine and carnassial teeth to tear meat and shear bone.

The two maxillary central incisor teeth in the front of the upper jaw are the most prominent teeth in the human mouth. They pair with the mandibular central incisors in the lower jaw for the primary cutting motion associated with the biting of food.

Mandibular central incisors are the smallest human teeth and have a relatively long, narrow shape compared to their wider maxillary counterparts. Both pairs of central incisors have a flat, blade-like profile that enables them to slice through food as it enters the mouth.

Maxillary lateral incisors are found on either side of the maxillary central incisors, and have a similar flat profile but are narrower in shape. The mandibular lateral incisor teeth are slightly larger than the mandibular central incisors and somewhat more rounded.