Nothing but the Tooth by Berkovitz Barry K.B

Author:Berkovitz, Barry K.B
Language: eng
Format: epub
ISBN: 9780123971937
Publisher: Elsevier Science
Published: 2012-11-27T16:00:00+00:00

Other Mammals

Crushing/cutting the food and absorbing its energy quickly is important in warm-blooded mammals. In many animals, the initial form of the teeth when they first erupt is not ideally suited to their grinding function. Take for example the grinding molar teeth of the hippopotamus. When they first erupt, the crowns possess smooth, rounded cusps that are inefficient in grinding up the tough vegetable matter on which the animal feeds (Figure 9.16A). After a ‘wearing-in’ period, the cusps are flattened to expose a complex pattern of folded ridges of enamel. Between the white enamel ridges are brownish areas of softer dentine and cement. As these three exposed dental tissues have different hardness levels, they wear away at different rates. Consequently, chewing food will leave the harder, more resistant, enamel at a higher level than the slightly softer dentine, ensuring that a roughened surface ideally adapted to masticate tough, abrasive vegetation is automatically maintained (Figure 9.16B). Imagine if the teeth, having been worn in and now suitable for function, were suddenly replaced by a new set that again required a lengthy ‘wearing-in’ process. This would clearly reduce the masticatory efficiency of the teeth. Hence, only two dentitions are present during life.

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