14 Although differences in tooth shape among mammalian

taxa have lead to the establishment of distinct categories of dental wear, principles adopted are similar and rely on standardization of criteria by the researcher. In odontocete cetaceans, homodonty and absence of cusps or other morphological features facilitates and simplifies the standardization of categories by using the estimated percentage of tooth loss.26 In our study, superficial wear was frequent in all species of dolphins with exception of the Clymene dolphin S. clymene and false killer whale P. crassidens. However, besides having small sample sizes, sampled specimens of both species were most likely adults due to their body length (see Table 1), a factor that could explain higher frequencies of moderate and severe wear in these species. For most of the other species analysed, although general prevalence of wear was selleck chemical high, wear was mostly superficial and affected enamel and outer dentine. This observation is consistent with the limited role of dolphin teeth in food processing and modified occlusion MAPK inhibitor resulting in interdigitation contact. 35 It is expected that the natural progression of wear will generate moderately to severely worn teeth. While superficial wear would have limited or negligible

implications for the fitness of individuals, moderate and severe wear could have the potential to expose the pulp cavity and lead to tissue necrosis and increase the susceptibility to infections. 30 and 41 In general, the occurrence of dental wear is related to progression of age.9, 11, 19, 20 and 23 In S. guianensis, Ramos et al. 24 observed that the height of the tooth crown and the height of the tooth itself were negatively related to the age of specimens,

due to the higher prevalence of Galeterone wear. Using the total body length (TBL) of individuals as a proxy to estimate age, we observed that our sample of S. guianensis did not follow the same trend established by Ramos et al. For our specimens, superficial wear was frequent even in bigger and potentially older animals. The weak association between indexes of wear and body size of specimens of D. capensis, L. hosei and S. guianensis suggests that, at least in these species, dental wear is common among all body sizes and age ranges and it is not influenced by growth and ageing processes. It would be expected that in those cases, interdigitation contact of upper and lower teeth played a more important role in generating dental wear than abrasion due to tooth use. Besides, allometric growth of teeth and body should also be taken into consideration. It means that different body parts may grow at varying rates during lifetime and could explain the weak association between dental wear and body size in these species. S. frontalis and T.