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Using electronic speckle pattern interferometry minipig molars were tested under load inside the bone socket and when embedded in a stiff polymer. It is demonstrated that the molar bends in the direction of the load in both configurations even at low loads. This shows that the intrinsic reaction of the tooth crown to load is complemented by the structures supporting the tooth.

Occlusal wear rate and wear plane in two Chalcolithic ( approximately 6500-5500 BP) samples from the southern Levant were compared, using paired first and second mandibular molars. Though food staples in both societies were derived from agro-pastoralism, they were located in distinct environmental regions: Wadi (W.) Makkukh in the Judean desert, and Peqi'in in the Upper Galilee. Accordingly, it was predicted that variation in wear should occur due to their location in distinct environments. Jaw size and tooth size were measured to estimate the possible impact of these variables on wear scores. Molar occlusal surfaces were divided into four quadrants, and wear scores were recorded for each quadrant. Principal axis analysis was then performed between total wear scores of paired, adjacent first and second molars to assess wear rates. Principal axis analysis was also used to analyze the change in occlusal wear plane in each sample by comparing between-buccal-cusps wear scores of the first molar with lingual wear scores of the second molar. The results indicate that the occlusal wear plane was similar in both samples but that wear tended to be more rapid in W. Makkukh. Since both samples were similar in jaw/tooth size, it is argued that the results reflect less refined food-processing methods as well as the unintentional ingestion of sand by individuals interred in the Judean desert.

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Teeth adopt a variety of different morphologies, each of which is presumably optimized for performing specific functions during feeding. It is generally agreed that the enamel cap is a crucial element in controlling the mechanical behavior of mammalian teeth under load. Incisors are particularly interesting in terms of structure-function relations, as their role in feeding is that of the 'first bite'. However, little is known how incisor cap morphology is related to tooth deformation. In the present paper we examine the mechanical behavior of mandibular central incisors in the cercopithecine primate Macaca mulatta under loads similar to those encountered during ingestion. We map three-dimensional displacements on the labial surface of the crown as it is compressed, using electronic speckle pattern interferometry (ESPI), an optical metrology method. In addition, micro-computed tomography is used to obtain data regarding the morphology of the enamel cap, which in the M. mulatta lower incisors exhibits missing or very little enamel on the lingual face. The results showed that although compressed along a longitudinal axis, deformation in the incisors mostly occurred in the lingual direction and orthogonal to the direction of the applied load. Both isolated, embedded teeth and teeth in the mandible showed considerable lingual deformation. Incisor deformation in the mandible was generally greater, reflecting the additional freedom of movement enabled by the supporting structures. We show that the association with adjacent teeth in the arch is significant for the behavior of the tooth under load. Finally, loading two teeth simultaneously in the mandible showed that they work as one functional unit. We suggest that these results demonstrate the importance of enamel cap morphology in directing deformation behavior; an ability stemming from the stiffness of the enamel cap overlying the more pliable dentin.