title: Effect of power settings on temperature change at the root surface when using a Holmium YAG laser in enlarging the root canal.
abstract: The aim of this study was to determine the maximum amount of power, in watts, that a Holmium YAG laser could deliver via a 245-micron fiberoptic to the canal surface and still not raise the temperature (delta T) of the cementum by > 5 degrees C. Sixty single-rooted teeth were divided into three groups according to power selection (0.50, 0.75, and 1.00 W). The three main outcome variables were: change in apical temperature, change in coronal temperature, and maximum size of an endodontic file that could fit into the canal after lasing. The group means for apical delta T were: 1.00 W = 2.2 degrees C, 0.75 W = 2.68 degrees C, and 0.50 W = 1.58 degrees C. The group means for coronal delta T were: 1.00 W = 1.15 degrees C, 0.75 W = 0.99 degree C, and 0.50 W = 0.56 degree C. The group means for file size were: 1.00 W = 41.25, 0.75 W = 38.75, and 0.50 W = 40.75. The canal size was increased from a size 25 file up to approximately a size 40 file with all power groups. There were no significant differences between the groups for change in apical temperature (p = 0.32), coronal temperature (p = 0.17), or maximum file size (p = 0.86) when adjustments were made for tooth dimensions. In all groups studied, the delta T was < 5 degrees C. This represents a safe and predictable laser procedure.
authors.affiliation: Division of Dental Research, Essential Dental Laboratory, South Hackenasck, NJ 07806, USA.
authors.forename: B I
authors.initials: BI
authors.lastname: Cohen
authors.forename: A S
authors.initials: AS
authors.lastname: Deutsch
authors.forename: B L
authors.initials: BL
authors.lastname: Musikant
mesh_terms: D000704:Analysis of Variance; D001831:Body Temperature; D003739:Dental Cementum / Q000502:physiology; D006695:Holmium; D006358:Hot Temperature; D006801:Humans; D007834:Lasers; D018915:Root Canal Preparation / Q000295:instrumentation*; D013499:Surface Properties; D013814:Thermal Conductivity; D015019:Yttrium
chemical_list: D015019:Yttrium; D006695:Holmium