title: Structural and distribution patterns of surface 'prismless' enamel in human permanent teeth.
abstract: Using human permanent teeth, structural and distribution patterns of the surface 'prismless' enamel with the occasional presence of indistinct and/or stunted prism structures were investigated by scanning electron microscopy. The 'prismless' enamel was classified into three shapes: step-like, occurring in mid-coronal enamel; band-like, frequently seen in occlusal and fissure enamel, and island-like, found in occlusal and cuspal-coronal enamel. These three 'prismless' shapes were formed by two structural patterns. One was determined by prisms which gradually changed into 'prismless' structures via indistinct and stunted prisms (prism-dependent; P type), and another, probably a variance of the P type, was characterized by prisms which abruptly changed into 'prismless' structures on the incremental lines of Retzius or the fine laminated striations (Retzius-dependent; R type). The P type pattern clearly forming the band and island-like shapes was found in occlusal and cuspal-coronal enamel, whereas the R type pattern forming some of the band-like shapes as well as the step-like shapes might be observed in almost all surface enamel.
authors.affiliation: Second Department of Oral Anatomy, School of Dentistry, Showa University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kodaka
authors.forename: M
authors.initials: M
authors.lastname: Kuroiwa
authors.forename: S
authors.initials: S
authors.lastname: Higashi
mesh_terms: D000293:Adolescent; D000328:Adult; D001641:Bicuspid; D002648:Child; D003743:Dental Enamel / Q000737:chemistry / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008963:Molar; D008964:Molar, Third; D013499:Surface Properties; D014097:Tooth, Unerupted