the prevalent crack shielding mechanism observed in the hydrated dentin core. 25
MACROSTRUCTURE: CONVEX ENAMEL VS. CONCAVE DENTIN
Most topographic structures are related to the different functional roles of the enamel and dentin surfaces. The robust, rounded convex contours of the enamel surface provide strength to a tissue subjected to direct masticatory stresses and occlusal loads. In contrast, the sharp, concave relief of the dentin surface provides a stable support for the enamel shell. (FIG 5+6.) From a bio-mechanical viewpoint, harmony between the ectodermal and mesodermal tissues was necessary for the selective adaptation of teeth, with the DEC proving to be the most intricate of mechanisms, imparting the structural efficiency of an interconnecting network, where the various structural elements function in unison rather than remaining independent from each other. The DEC therefore is considered as functional shielding mechanism, that should be preserved, whenever possible during clinical restorative procedures. Bio-mechanical force loads are thus allowed to transmit freely through the surfaces, dissipating throughout this structurally fluid
Morphologic Features
Enamel Surface
Dentin Surface
Marginal Ridges
Rounded
Sharp
Buccal Cusp/s
Rounded
Sharp
Lingual Cusp/s
Rounded
Sharp
Concave 26,27
Buccal Surface
Convex
Lingual Surface
Convex
Concave
Occlusal Fissures
Present
Absent
Table 1. Visual Observations of the Posterior Enamel/Dentin Surface Correlations
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