title: Permeability, morphologic and temperature changes of canal dentine walls induced by Nd: YAG, CO2 and argon lasers.
abstract: The permeability, temperature and morphologic changes of the wall of the root canal induced by Nd:YAG, CO2 and argon lasers were studied. The changes were evaluated according to the presence or absence of a smear layer. Root canals of 140 human single-rooted teeth were enlarged using a step-back technique. Permeability was evaluated by the extent of methylene blue dye penetration into the tubules. Temperature changes were measured using a thermovision system, and morphological changes were evaluated by scanning electron microscopy. Laser energy was delivered into the canal by means of a flexible optical fibre or metal tip. There were statistically significant differences in permeability between lased groups with and without a smear layer in the cervical third of the root canal following lasing. In the middle third of the root canal, all three laser types induced permeability increases in groups with a smear layer. In the apical third, statistically significantly decreases in permeability were observed among CO2 laser and Nd:YAG compared with control group (P < 0.01). Rises in temperature ranged from a minimum of +10.1 degrees C (CO2 laser) to a maximum of +54.8 degrees C (argon laser). All three laser devices appeared capable of producing a glazed-like surface and craters.
authors.affiliation: Department of Dental Pathology, School of Dentistry, University of Zagreb, Croatia.
authors.forename: I
authors.initials: I
authors.lastname: Anić
authors.forename: H
authors.initials: H
authors.lastname: Tachibana
authors.forename: K
authors.initials: K
authors.lastname: Masumoto
authors.forename: P
authors.initials: P
authors.lastname: Qi
mesh_terms: D000704:Analysis of Variance; D001128:Argon; D001831:Body Temperature; D002245:Carbon Dioxide; D003786:Dental Pulp Cavity / Q000502:physiology / Q000528:radiation effects*; D003804:Dentin / Q000502:physiology / Q000528:radiation effects*; D003806:Dentin Permeability / Q000528:radiation effects*; D006358:Hot Temperature; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D009354:Neodymium; D013499:Surface Properties; D014092:Tooth Root / Q000502:physiology / Q000528:radiation effects
chemical_list: D002245:Carbon Dioxide; D009354:Neodymium; D001128:Argon