title: Age-related changes in tooth enamel as measured by electron microscopy: implications for porcelain laminate veneers.
abstract: BACKGROUND
  Available information on the dimensions of the enamel and pulp tissues of tooth structure, as well as their correlation with chronologic age, is limited. However, this information is a significant determinate in planning the tooth reduction for a porcelain laminate veneer (PLV) restoration.
  
  
  OBJECTIVE
  This study examined variations in tooth enamel thickness and its correlation with chronologic age as it relates to available tooth substrate for PLV restorations.
  
  
  METHODS
  Forty human maxillary central incisors extracted from patients within the age range of 30 to 69 years were used to evaluate the thickness of tooth layers. Measurements were made for the following tooth areas using scanning electron microscopy (SEM): facial enamel thickness at 1, 3, and 5 mm above the cemento-enamel junction (CEJ), palatal enamel thickness at 5 mm above the CEJ, facial and palatal enamel thickness at the incisal edge, maximum facial-palatal (MFP) width at incisal edge, physiologic secondary dentin (PSD) height, facial-cervical enamel-pulp (FCEP) distance, and the incisal edge enamel-pulp (IEP) distance. The relationship between thickness and age was evaluated with a regression analysis (alpha=.05).
  
  
  RESULTS
  Significant differences (P<.001) were observed in all of the relationships between tooth thicknesses and chronological age. Outcome variables of enamel thickness related to age showed a steady decrease, beginning at approximately age 50. Mean values of facial enamel thickness at 1, 3, and 5 mm above the CEJ were 0.31 +/- 0.01, 0.54 +/- 0.01, and 0.75 +/- 0.02 mm, respectively, for the age range of 30 to 69 years. The thickness of maximum incisal width (R(2) = 0.95), PSD height (R(2) = 0.76), and IEP distance (R(2) = 0.99) indicated that all are subject to an increase in relation to age.
  
  
  CONCLUSIONS
  Facial enamel thickness above the CEJ decreases, while MFP increases in relation to age. The PSD height and IEP distance also increased with age.
authors.affiliation: Department of Prosthodontics, Faculty of Dental Medicine, Kirikkale University, Kirikkale, Turkey. saadetats@yahoo.com
authors.forename: Saadet Saglam
authors.initials: SS
authors.lastname: Atsu
authors.forename: P Sema
authors.initials: PS
authors.lastname: Aka
authors.forename: H Cenker
authors.initials: HC
authors.lastname: Kucukesmen
authors.forename: Mehmet A
authors.initials: MA
authors.lastname: Kilicarslan
authors.forename: Cemal
authors.initials: C
authors.lastname: Atakan
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D003743:Dental Enamel / Q000648:ultrastructure*; D003776:Dental Porcelain; D003782:Dental Pulp / Q000648:ultrastructure; D003801:Dental Veneers; D003809:Dentin, Secondary / Q000648:ultrastructure; D006801:Humans; D007180:Incisor; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D009811:Odontometry; D019237:Tooth Cervix / Q000648:ultrastructure; D019228:Tooth Crown / Q000648:ultrastructure
chemical_list: D003776:Dental Porcelain