title: Near-ultraviolet removal rates for subgingival dental calculus at different irradiation angles.
abstract: The laser ablation rate of subgingival dental calculus irradiated at a 400-nm-wavelength, 7.4-mJ pulse energy, and 85- and 20-deg irradiation angles is measured using laser triangulation. Three-dimensional images taken before and after irradiation create a removal map with 6-μm axial resolution. Fifteen human teeth with subgingival calculus are irradiated in vitro under a cooling water spray with an ∼300-μm-diam, tenth-order super-gaussian beam. The average subgingival calculus removal rates for irradiation at 85 and 20 deg are 11.1±3.6 and 11.5±5.9 μm∕pulse, respectively, for depth removal and 4.5±1.7×10(5) and 4.8±2.3×10(5) μm(3)∕pulse, respectively, for volume removal. The ablation rate is constant at each irradiation site but varies between sites because of the large differences in the physical and optical properties of calculus. Comparison of the average depth- and volume-removal rates does not reveal any dependence on the irradiation angle and is likely due to the surface topology of subgingival calculus samples that overshadows any expected angular dependence.
authors.affiliation: University of Rochester, Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA. jscho@lle.rochester.edu
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Schoenly
authors.forename: Wolf D
authors.initials: WD
authors.lastname: Seka
authors.forename: Peter
authors.initials: P
authors.lastname: Rechmann
mesh_terms: D003728:Dental Calculus / Q000473:pathology / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods*; D053844:Lasers, Solid-State / Q000627:therapeutic use; D055620:Optical Phenomena; D014466:Ultraviolet Rays