title: [Comparative study of friction and wear behavior of different human enamel in vitro].
abstract: OBJECTIVE
  To investigate the friction and wear behavior of different human enamels.
  
  
  METHODS
  24 enamel samples selected from aged, young permanent and faded deciduous teeth were classified into 3 groups and slid against artificial porcelain teeth in the presence of artificial saliva on an oscillating friction and wear test rig. The wear volume loss, microhardness and toughness of each group of the enamel specimens were measured, the wear scars were observed with a scanning electron microscope, and the elemental compositions of Ca, P, and Si of the wear scar and wear debris were determined with an energy dispersion spectrometer.
  
  
  RESULTS
  The wear volume losses of aged, young permanent and deciduous tooth enamels are (2.40 +/- 1.10) x 10(-12) m(3), (3.50 +/- 1.83) x 10(-12) m(3) and (4.86 +/- 2.49) x 10(-12) m(3). The data of aged tooth enamels are statistically greater than that of deciduous tooth enamels (P < 0.05). There is no significant difference between the wear volume loss of aged and young permanent tooth enamels or between the young permanent and deciduous tooth enamels (P > 0.05). However, the friction and wear behavior of each group of enamel specimens is different from each other.
  
  
  CONCLUSIONS
  In the present testing condition, the wear scars of each kind of enamel specimens is characterized by ploughing and cracking. The different wear resistance of the three kinds of enamels is attributed to the different microstructure of the enamel, while the hardness and toughness of the enamels are not correlated with the wear resistance.
authors.affiliation: Department of Stomatology, Lanzhou General Hospital, Lanzhou Command PLA, Lanzhou 730050, China.
authors.forename: Yi-nong
authors.initials: YN
authors.lastname: Qiu
authors.forename: Wei-min
authors.initials: WM
authors.lastname: Liu
authors.forename: Tong-sheng
authors.initials: TS
authors.lastname: Li
authors.forename: Lan-zhong
authors.initials: LZ
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003743:Dental Enamel / Q000473:pathology*; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D014072:Tooth Abrasion / Q000473:pathology*; D014094:Tooth, Deciduous