title: Root surface roughness following Er:YAG laser irradiation at different radiation energies and working tip angulations.
abstract: OBJECTIVE
  The determination of roughness of root surfaces following treatment with 2.94 micro m Er:YAG laser radiation at different radiation energies and working tip angulations.
  
  
  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 micro m, with a pulse duration of 250 micro s, 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 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees. Five samples were treated mechanically using curettes. Five samples were left untreated as control. The mean (Ra) and maximum (Rmax) surface roughness of each sample was measured using a profilometer. The statistical analysis was undertaken using anova and Scheffé-test at a level of significance of 5% (p < 0.05).
  
  
  RESULTS
  Er:YAG laser radiation led to an Ra which ranged from 0.52 micro m (+/- 0.10) to 0.81 micro m (+/- 0.26) and to an Rmax between 3.4 micro m (+/- 0.48) and 9.26 micro m (+/- 3.08). The Ra and Rmax for samples treated with curettes was 0.51 micro m (+/- 0.11) and 5.08 micro m (+/- 4.98), respectively. That for the untreated control samples were 0.53 micro m (+/- 0.15) and 7.07 micro m (+/- 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.
mesh_terms: D000538:Aluminum Silicates; D000704:Analysis of Variance; D004867:Equipment Design; D004871:Erbium; D006801:Humans; D053685:Laser Therapy; D011829:Radiation Dosage; D013223:Statistics as Topic; D013357:Subgingival Curettage / Q000295:instrumentation / Q000379:methods; D013499:Surface Properties; D014092:Tooth Root / Q000528:radiation effects* / Q000648:ultrastructure; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D015019:Yttrium; D004871:Erbium