Figure 2
Relationship of intercuspal distance and concavity of axial outline with cervical tongue pattern. (a) Three-dimensionally (3D) reconstructed micro-computed topographies of PN14 mouse and PN21 rat first molars (M1) scaled to the same size from occlusal view. Black dots indicate highest points of each cusps and the lines connecting them are the reference lines for distance between cusps measured. (b,c) The distance between cusps in ratio to the mesiodistal diameter are compared between mouse (white bar) and rat (filled bar) in mandible (Mn) and maxilla (Mx). (d) Two-dimensional average (median) crown outlines of PN14 mouse and PN21 rat first molars (n = 5) generated based on Radial Fourier method is depicted. Concave axial outline in intercuspal regions where distinctions are observed between mouse outlines (black line) and rat outlines (red lines) are indicated by black arrowheads. (e) For the degree of concavity, tangent lines touching two convex outlines next to an intercuspal region were created in each tooth, and the area between the tooth outline and the tangent line was obtained and colored in light blue. (f) The concave area was measured and scaled to the total tooth area of two-dimentional outline, and then compared between mouse and rat (n = 5). P < 0.05.
