title: Dental enamel irradiated with a low-intensity infrared laser and photoabsorbing cream: a study of microhardness, surface, and pulp temperature.
abstract: OBJECTIVE
  The aim of this study was to assess the effect of low-intensity infrared laser light (λ=810 nm, 100 mW/cm(2), 90 sec, 4.47 J/cm(2), 9 J) with or without indocyanine green cream fluorinated or not fluorinated, using Knoop surface microhardness analysis.
  
  
  BACKGROUND
  Lasers can be used as tools for the prevention of tooth enamel demineralization.
  
  
  METHODS
  The surface and pulp temperatures of the human deciduous tooth enamel were measured. For the analysis of surface hardness, a total of 48 specimens were prepared and randomly assigned into six groups (n=8/group): C (+), which received laser light; C(-), which received no treatment; cream (IV); cream and fluoride (IVF); cream and light (IVL); and cream and fluoride and light (IVFL). The specimens were subjected to treatment before demineralizing challenge by pH cycling. To analyze the surface and pulp temperatures, the samples were divided into the following groups (n=10): C(+), IVL, and IVFL.
  
  
  RESULTS
  The hardness analysis indicated that the groups that received irradiation had less hardness reduction following the demineralizing challenge (p<0.001), with IVFL and IVL presenting the lowest percentages of surface microhardness loss at 3.98% and 9.3%, respectively. Surface temperature analysis indicated a maximum increase of 74°C and a mean of 45.25°C and 45.95°C for the IVL and IVFL groups, respectively. Pulp temperature analysis indicated a higher mean increase of 2.40°C±0.65 in the IVL group.
  
  
  CONCLUSIONS
  These results suggest that the combination of cream and laser light possibly promoted protein denaturation of the tooth enamel organic matrix, which possibly decreased the loss of hardness without causing pulp damage.
authors.affiliation: 1 Pediatric Dentistry, Cruzeiro do Sul University (UNICSUL) , São Paulo, Brazil .
authors.forename: Patricia
authors.initials: P
authors.lastname: da Silva Barbosa
authors.forename: Patricia Aparecida
authors.initials: PA
authors.lastname: da Ana
authors.forename: Isis Andréa Venturini Pola
authors.initials: IA
authors.lastname: Poiate
authors.forename: Denise Maria
authors.initials: DM
authors.lastname: Zezell
authors.forename: Giselle Rodrigues
authors.initials: GR
authors.lastname: de Sant' Anna
mesh_terms: D004396:Coloring Agents / Q000008:administration & dosage*; D003743:Dental Enamel / Q000528:radiation effects*; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007208:Indocyanine Green / Q000008:administration & dosage*; D054023:Lasers, Semiconductor; D008963:Molar; D009824:Ointments; D011897:Random Allocation; D013499:Surface Properties; D013696:Temperature; D017001:Tooth Demineralization
chemical_list: D004396:Coloring Agents; D009824:Ointments; D007208:Indocyanine Green