The purpose of this study was to evaluate the effect of
erbium:
yttrium-aluminum-garnet (
Er:YAG) laser (2.94 mum) irradiation on the removal of root surface
smear layer of extracted human teeth and to compare its efficacy with that of
citric acid,
ethylenediamine tetra-
acetic acid (
EDTA), or a gel containing a mixture of
tetracycline hydrochloride (HCl) and
citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic
saline solution; G2, conditioned with 24%
citric acid gel; G3, conditioned with 24%
EDTA gel; G4, conditioned with a 50%
citric acid and
tetracycline gel; G5, irradiated with
Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with
Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the
Er:YAG laser groups and those undergoing the other treatment modalities. When the two
Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in
smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by
Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in
smear layer removal. The results of our study suggest that the
Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of
Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.