title: Erbium laser ablation of dental hard tissue: effect of water cooling.
abstract: OBJECTIVE
  Several lasers have been explored for hard dental tissue applications; used alone they have resulted in potentially harmful temperature increases in the pulp chamber.
  
  
  METHODS
  An Er:YAG laser (lambda = 2.94 microns) was used to ablate hard dental tissues. Ablation rates with and without a water-cooling spray were measured. Subsequent experiments investigated the cooling effects of the water. Initially single channels were drilled into dentin; further studies involved ablating rectangular areas with repetition rates up to 10 Hz.
  
  
  RESULTS
  The water spray minimally reduced the ablation rates of dentin and did not affect the ablation rates of enamel. The water spray effectively cooled the teeth; while using the maximum average power investigated (10 Hz, 360 mJ/pulse), a water flow rate of 4.5 ml/min limited the temperature rise in the pulp chamber to less than 3 degrees C.
  
  
  CONCLUSIONS
  The studies confirm the feasibility of using an Er:YAG laser in conjunction with a water spray to safely and effectively remove hard dental tissues.
authors.affiliation: Biomedical Engineering Department, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Visuri
authors.forename: J T
authors.initials: JT
authors.lastname: Walsh
authors.forename: H A
authors.initials: HA
authors.lastname: Wigdor
mesh_terms: D003080:Cold Temperature; D003804:Dentin / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation*; D013696:Temperature; D007507:Therapeutic Irrigation / Q000295:instrumentation*