title: Qualitative analysis of teeth and evaluation of amalgam elements penetration into dental matrix using laser induced breakdown spectroscopy.
abstract: BACKGROUND
  In this study, laser induced breakdown spectroscopy (LIBS) is used for qualitative analysis of healthy and carious teeth. The technique of laser ablation is receiving increasing attention for applications in dentistry, specifically for the treatment of teeth such as drilling of micro-holes and plaque removal.
  
  
  METHODS
  A quality-switched (Q-switched) Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser operating at wavelength of 1064 nm, pulse energy of 90 mJ/pulse, repetition rate of 2Hz and pulse duration of 6 ns was used in this analysis. In the process of ablation a luminous micro-plasma is normally generated which may be exploited for on-line elemental analysis via laser induced breakdown spectroscopy technique. We propose laser induced breakdown spectroscopy as a rapid, in situ and easy method for monitoring drilling process.
  
  
  RESULTS
  The results of elemental analysis show the presence of some trace elements in teeth including P, Ca, Mg, Zn, K, Sr, C, Na, H, O and the permeability of some amalgam (teeth filling materials) elements including Hg, Ag, Cu and Sn into dental matrix.
  
  
  CONCLUSIONS
  This study addresses the ability of LIBS in elemental analysis of teeth and its feasibility in acute identification of healthy and carious teeth during drilling process for future clinical applications.
authors.affiliation: Laser and Plasma Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, 1983963113, Iran.
authors.forename: Meisam
authors.initials: M
authors.lastname: Gazmeh
authors.affiliation: Laser and Plasma Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, 1983963113, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Bahreini
authors.affiliation: Laser and Plasma Research Institute, Shahid Beheshti University, G. C., Evin, Tehran, 1983963113, Iran.
authors.forename: Seyed Hassan
authors.initials: SH
authors.lastname: Tavassoli
authors.affiliation: Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Asnaashari
keywords: amalgam; carious; spectroscopy; tooth