Ex vivo study of the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasers.
OBJECTIVE
To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters.


METHODS
Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II-V were irradiated with Er : YAG laser at the following parameters: group II - 8 Hz and 200 mJ input (120 mJ output); group III - 8 Hz and 400 mJ input (240 mJ output); group IV - 16 Hz and 200 mJ input (120 mJ output); group V - 16 Hz and 400 mJ input (240 mJ output). Groups VI-IX were irradiated with Nd : YAG laser at the following parameters: group VI - 10 Hz and 1 W input (0.4 W output); group VII - 10 Hz and 2 W input (0.8 W output); group VIII - 15 Hz and 1 W input (0.4 W output); group IX - 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test.


RESULTS
Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values.


CONCLUSIONS
An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer.
Sousa-Neto
M D
MD
Faculty of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil. sousanet@unaerp.br
Silva Coelho
F I
FI
Marchesan
M A
MA
Alfredo
E
E
Silva-Sousa
Y T C
YT
D000538:Aluminum Silicates; D001729:Bismuth / Q000737:chemistry; D002126:Calcium Hydroxide / Q000737:chemistry; D002614:Chelating Agents / Q000494:pharmacology; D003481:Cuspid; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004853:Epoxy Resins / Q000737:chemistry*; D004871:Erbium; D006801:Humans; D007834:Lasers; D009354:Neodymium; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000494:pharmacology; D015019:Yttrium
D000538:Aluminum Silicates; D002614:Chelating Agents; D004853:Epoxy Resins; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C080620:Sealer 26; D009354:Neodymium; D015019:Yttrium; C033443:EDTAC; D004871:Erbium; D004492:Edetic Acid; D002126:Calcium Hydroxide; D001729:Bismuth