title: Argon and Nd:YAG lasers for caries prevention in enamel.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of Nd:YAG and argon laser irradiations on enamel demineralization after two different models to induce artificial caries.
  
  
  BACKGROUND
  It is believed that the use of the high-intensity laser on the dental structure can lead to a more acid-resistant surface.
  
  
  METHODS
  Twenty-one extracted human third molars were sectioned into tooth quarters. The quarters were distributed in three groups: Group I (control), untreated; Group II, Nd:YAG laser (60 mJ, 15 pps, 47.77 J/cm(2), 30 sec); and Group III, argon laser (250 mW, 12 J/cm(2), 48 sec). Tooth quarters from each group were subjected to two different demineralization models: cycle 1, a 14 day demineralization (pH 4.5; 6 h) and remineralization (pH 7.0; 18 h) solutions, 37 °C and cycle 2, 48 h in demineralization solution (pH 4.5). Samples were prepared in slices (60-100 μm thick) to be evaluated under polarized light microscopy. Demineralization areas were measured (mm(2)) (n=11). Data were analyzed by ANOVA and Tukey's test (p<0.05).
  
  
  RESULTS
  Means followed by different letters are significantly different: 0.25 A (control, cycle 48 h); 0.18 AB (control, cycle 14 days); 0.17 AB (Nd:YAG, cycle 14 days); 0.14 BC (argon, cycle 48 h); 0.09 BC (Nd:YAG, cycle 48 h), and 0.06 C (argon, cycle 14 days).
  
  
  CONCLUSIONS
  The argon laser was more effective for caries preventive treatment than Nd:YAG laser, showing a smaller demineralization area in enamel.
authors: Department of Preventive Dentistry, School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil. jutavar@terra.com.br
authors: Julieta Gomes
authors: JG
authors: Tavares
authors: Carlos de Paula
authors: Cde P
authors: Eduardo
authors: Luiz Henrique
authors: LH
authors: Burnett
authors: Teonas Renato
authors: TR
authors: Boff
authors: Patrícia Moreira
authors: PM
authors: de Freitas
mesh_terms: D000704:Analysis of Variance; D003731:Dental Caries / Q000517:prevention & control*; D003743:Dental Enamel / Q000528:radiation effects*; D006801:Humans; D066298:In Vitro Techniques; D054018:Lasers, Excimer; D053844:Lasers, Solid-State; D008964:Molar, Third / Q000528:radiation effects*; D017001:Tooth Demineralization / Q000517:prevention & control*