31. Tertiary dentin is dentin formed as a reaction to external stimulation such as cavities. 32. Because dentin is softer than enamel, it wears away more quickly than enamel. 33. In the longitudinal section of a tooth . these lines appear near the dentin . 34. The procedure was later adopted by ADA for measuring of Relative Dentin Abrasion Index. 35. In contrast, reparative dentin is secreted when the tooth has a poor prognosis. 36. By 1997 the only original gods remaining active were Dentin , Wyvren and Heart. 37. The faster spread of caries through dentin creates this triangular appearance in smooth surface caries. 38. Dentin is a bone-like matrix that is porous and yellow-hued material.39. It is usually 10-47 micrometer and lines the innermost region of the dentin . 40. Odontoblasts, the dentin -forming cells, differentiate from cells of the dental papilla.
