Bunodont[edit]
Upper and lower dentition of a chimpanzee
In bunodont molars, the cusps are low and rounded hills rather than sharp peaks. They are most common among omnivores such as pigs, bears and humans.[7] Bunodont molars are effective crushing devices and often basically quadrate in shape.[8]
Hypsodont[edit]
Hypsodont dentition is characterized by high-crowned teeth and enamel that extends far past the gum line, which provides extra material for wear and tear.[9] Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on gritty, fibrous material. Hypsodont molars can continue to grow throughout life, for example in some species of Arvicolinae (herbivorous rodents).[7]
Hypsodont molars lack both crown and neck. The occlusal surface is rough and mostly flat, adapted for crushing and grinding plant material. The body is covered with cementum both above and below the gingival line, below which is a layer of enamel covering the entire length of the body. The cementum and the enamel invaginate into the thick layer of dentin.[10]
Brachydont[edit]
The opposite condition to hypsodont is called brachydont or brachyodont (from brachys, "short"). It is a type of dentition characterized by low-crowned teeth. Human teeth are brachydont.[7]
A brachydont tooth has a crown above the gingival line and a neck just below it, and at least one root. A cap of enamel covers the crown and extends down to the neck. Cementum is only found below the gingival line. The occlusal surfaces tend to be pointed, well-suited for holding prey and tearing and shredding.[10]
Zalambdodont[edit]
Zalambdodont molars have three cusps, one larger on the lingual side and two smaller on the labial side, joined by two crests that forms a V- or lambda-shape. The larger inner cusp might be homologous with the paracone in a tribosphenic molar, but can also be fused with the metacone. The protocone is typically missing. The two smaller labial cusps are located on an expanded shelf called the stylar shelf. Zalambdodont molars are found in for example golden moles and solenodons.[7]
Dilambdodont[edit]
Like zalambdodont molars, dilambdodont molars have a distinct ectoloph but shaped like two lambdas or a W. On the lingual side, at the bottom of the W, are the metacone and paracone, and the stylar shelf is on the labial side. A protocone is present lingual to the ectoloph. Dilambdodont molars are present in shrews, moles, and some insectivorous bats.[7]