<title>Treatment of dentinal tubules by Nd:YAG laser</title>

Abstract

Symptom of cervical dentine hypersensitivity attacks from 10 % to 15 % of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, nonporous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNCdriven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 J.cm2. Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used.The best samples were investigated by means ofthe Atomic Force Microscopy.

Sealing of open dentinal tubules by laser irradiation: AFM and SEM observations of dentine surfaces

“…Parameters of the generated intense laser pulses can vary in broad ranges and this enables us to study the pulse interaction with a dentine surface (Perina et al, 2004;Chmelickova et al, 2005;Zapletalova et al, 2007) under conditions not always accessible by special dental lasers. Using a beam with a diameter of 0.6 mm, an energy of 200 mJ per pulse or higher is required for the modification of a dentine surface assuming onefold irradiation.…”