In each jaw, four small molars were placed in pairs next to the canines. These teeth have broad surface or sharp ridges that are used for chewing, crushing and grinding food. Early humans also had four small molars in the jaw that were larger in size and the burrs on them were sharper. Today, the number of these teeth is also decreasing.
In some modern humans, from the series of minor molar teeth, tooth buds #5 are smaller than normal or these tooth buds may not form. Thus, due to the lack of sufficient space in the jaws, the number of teeth is reduced. If the number of teeth is large and the jaw is small, the teeth grow irregularly and are crowded. So, they need treatment, they should go to an orthodontist and start orthodontic treatment.