title: Caries inhibition in vital teeth using 9.6-μm CO2-laser irradiation.
abstract: The aim of this study was to test the hypothesis that in a short-term clinical pilot trial short-pulsed 9.6 μm CO(2)-laser irradiation significantly inhibits demineralization in vivo. Twenty-four subjects scheduled for extraction of bicuspids for orthodontic reasons (age 14.9 ± 2.2 years) were recruited. Orthodontic brackets were placed on bicuspids (Transbond XT, 3M). An area next to the bracket was irradiated with a CO(2)-laser (Pulse System Inc, Los Alamos, New Mexico), wavelength 9.6 μm, pulse duration 20 μs, pulse repetition rate 20 Hz, beam diameter 1100 μm, average fluence 4.1 ± 0.3J∕cm(2), 20 laser pulses per spot. An adjacent nonirradiated area served as control. Bicuspids were extracted after four and twelve weeks, respectively, for a quantitative assessment of demineralization by cross-sectional microhardness testing. For the 4-week arm the mean relative mineral loss ΔZ (vol% × μm) for the laser treated enamel was 402 ± 85 (mean ± SE), while the control showed significantly higher mineral loss (ΔZ 738 ± 131; P = 0.04, t-test). The difference was even larger after twelve weeks (laser arm ΔZ 135 ± 98; control 1067 ± 254; P = 0.002). The laser treatment produced 46% demineralization inhibition for the 4-week and a marked 87% inhibition for the 12-week arm. This study shows, for the first time in vivo, that the short-pulsed 9.6 μm CO(2)-laser irradiation successfully inhibits demineralization of tooth enamel in humans.
authors.affiliation: University of California at San Francisco, Department of Preventive and Restorative Dental Sciences, School of Dentistry, 707 Parnassus Avenue, San Francisco, California 94143, USA. rechmannp@dentistry.ucsf.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Rechmann
authors.forename: Daniel
authors.initials: D
authors.lastname: Fried
authors.forename: Charles Q
authors.initials: CQ
authors.lastname: Le
authors.forename: Gerald
authors.initials: G
authors.lastname: Nelson
authors.forename: Marcia
authors.initials: M
authors.lastname: Rapozo-Hilo
authors.forename: Beate M T
authors.initials: BM
authors.lastname: Rechmann
authors.forename: John D B
authors.initials: JD
authors.lastname: Featherstone
mesh_terms: D000293:Adolescent; D002648:Child; D003731:Dental Caries / Q000517:prevention & control*; D003743:Dental Enamel / Q000737:chemistry / Q000528:radiation effects; D005260:Female; D006245:Hardness Tests; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D016910:Orthodontic Brackets; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D017001:Tooth Demineralization / Q000517:prevention & control