Root surface roughness following Er:YAG laser irradiation at different radiation energies and working tip angulations

Objectives: The determination of roughness of root surfaces following treatment with 2.94 mum Er:YAG laser radiation at different radiation energies and working tip angulations. Materials and methods: The study sample comprised 85 extracted human molars, premolars, canines and incisors (n = 85). The source of laser radiation was an Er:YAG laser device (KAVO-Key II, System Aesculap Meditec) emitting pulsed infrared radiation at a wavelength of 2.94 mum, with a pulse duration of 250 mus, and a pulse repetition rate of 10 pps. The samples were randomly divided into three experimental units, for treatment with a constant amount of 380 laser pulses at a radiation energy of 60 mJ, 100 mJ, and 180 mJ. Each experimental unit was divided into five subgroups of five samples, which were irradiated at a working tip angulations of 15degrees, 30degrees, 45degrees, 60degrees, and 90degrees. Five samples were treated mechanically using curettes. Five samples were left untreated as control. The mean (R-a ) and maximum (R-max ) surface roughness of each sample was measured using a profilometer. The statistical analysis was undertaken using anova and Scheffe-test at a level of significance of 5% (p < 0.05). Results: Er:YAG laser radiation led to an R-a which ranged from 0.52 mum (+/- 0.10) to 0.81 mum (+/- 0.26) and to an R-max between 3.4 mum (+/- 0.48) and 9.26 mum (+/- 3.08). The R-a and R-max for samples treated with curettes was 0.51 mum (+/- 0.11) and 5.08 mum (+/- 4.98), respectively. That for the untreated control samples were 0.53 mum (+/- 0.15) and 7.07 mum (+/- 5.48), respectively. Conclusions: The mean and maximum surface roughness of root surfaces following irradiation with Er:YAG laser was not significantly different to that obtained on samples treated with conventional hand instruments or left untreated. Furthermore, the surface roughness does not depend on the radiation energy and the angulation of the working tip.