title: Morphological characteristics of primary enamel surfaces versus permanent enamel surfaces: SEM digital analysis.
abstract: OBJECTIVE
  The morphology of permanent and primary enamel surface merits further analysis. The objective of this study was to illustrate a method of SEM digital image processing able to quantify and discriminate between the morphological characteristics of primary and permanent tooth enamel.
  
  
  METHODS
  Sixteen extracted teeth, 8 primary teeth and 8 permanent teeth, kept in saline solution, were analysed. The teeth were observed under SEM. The SEM images were analysed by means of digitally processed algorithms. The two algorithms used were: Local standard deviation to measure surface roughness with the roughness index (RI); Hough's theorem to identify linear structures with the linear structure index (LSI).
  
  
  RESULTS
  The SEM images of primary teeth enamel show smooth enamel with little areas of irregularity. No linear structures are apparent. The SEM images of permanent enamel show a not perfectly smooth surface; there are furrows and irregularities of variable depth and width.
  
  
  CONCLUSIONS
  In the clinical practice a number of different situations require the removal of a thin layer of enamel. Only a good morphological knowledge of both permanent and primary tooth enamel gives the opportunity to identify and exploit the effects of rotary tools on enamel, thus allowing for a correct finishing technique.
authors.affiliation: Department of Medical-Surgical Sciences of Communication and Behavior School of Dental Hygiene, Dental School, University of Ferrara, Ferrara, Italy. lcclsn@unife.it
authors.forename: A
authors.initials: A
authors.lastname: Lucchese
authors.forename: E
authors.initials: E
authors.lastname: Storti
mesh_terms: D000465:Algorithms; D003743:Dental Enamel / Q000648:ultrastructure*; D004311:Double-Blind Method; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D014094:Tooth, Deciduous / Q000648:ultrastructure*