A thorough understanding of the histoanatomic structures and dynamic light interaction of the natural dentition provides dental practitioners with the ultimate strategic advantage with regard to optical integration of the final restoration. The first part of this article will attempt to provide insight on the threedimensional coronal configuration of natural teeth and on the utilization of this knowledge in the clinical and technical restorative approach. The main goals for this article are to identify and reveal previously unreported histo-anatomic interrelationships and to explain existing ones: the sigmoid curve distribution (convex enamel/concave dentin), the distinction between dentinoenamel "junction" (DEJ, visual interface) and dentinoenamel "complex" (DEC, functional interphase), and the structural significance of DEC preservation.