title: Treatment of root fracture by CO2 and Nd:YAG lasers: an in vitro study.
abstract: The purpose of this in vitro study was to use scanning electron microscopy and polarized light microscopy to evaluate the feasibility of using either the CO2 laser or an Nd:YAG laser in combination with air/water surface cooling to effect fusion of fractured tooth roots. The experimental unit consisted of 81 single-rooted teeth, each with an induced root fracture. Fifty-six teeth that had been reapproximated in dental stone and 25 teeth that had been reapproximated with C-clamps were assigned to untreated control groups or groups for treatment using CO2 and Nd:YAG lasers. Laser treatment consisted of multiple passes along the line of fracture, which was inspected using a dissecting microscope after each pass until a visual indication of fusion or irreparable damage resulted. Scanning electron microscopy evaluation of the treated lines revealed heat-induced fissures and cracks, areas of cementum meltdown and resolidification, crater formation, and separation of cementum from underlying dentin. In no instance-regardless of reapproximation technique, laser type, energy, and other parameters-did the treatment effect fusion of the fractured root halves.
authors.affiliation: Department of Periodontics, School of Dentistry, University of Missouri-Kansas City 64108, USA.
authors.forename: S
authors.initials: S
authors.lastname: Arakawa
authors.forename: C M
authors.initials: CM
authors.lastname: Cobb
authors.forename: J W
authors.initials: JW
authors.lastname: Rapley
authors.forename: W J
authors.initials: WJ
authors.lastname: Killoy
authors.forename: P
authors.initials: P
authors.lastname: Spencer
mesh_terms: D001128:Argon; D002245:Carbon Dioxide; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008859:Microscopy, Polarization; D009354:Neodymium; D011897:Random Allocation; D014082:Tooth Fractures / Q000601:surgery*; D014092:Tooth Root / Q000293:injuries*; D015019:Yttrium
chemical_list: D002245:Carbon Dioxide; D009354:Neodymium; D015019:Yttrium; D001128:Argon