title: Effect of chemical substances in removing methylene blue after photodynamic therapy in root canal treatment.
abstract: OBJECTIVE
  The disadvantage of photodynamic therapy (PDT) is in the photosensitizing agents that may stain the tooth structure. There is no register of PDT studies evaluating protocols to minimize that concern. The present study evaluated the efficiency of chemical adjuncts in methylene blue dye (MB) removal after PDT.
  
  
  METHODS
  Forty single-rooted teeth, after root canal preparation, were filled with 0.01% MB for 5  min, and irradiated with diode laser 660  nm at 40  mW for 240  sec (total energy 9.6  J). The specimens were divided into four groups (n = 10), according to the chemical adjuncts used for dye removal: (a) 2.5% sodium hypochlorite (NaOCl); (b) 2.5% NaOCl + Endo-PTC cream; (c) 70% ethyl alcohol and (d) saline (control). The crowns were sectioned and fixed in a device. Photographs were taken before the PDT (T0), immediately after (T1) and upon dye removal (T2). The chromatic alterations were evaluated using Adobe Photoshop and K values were determined in four fixed points of each crown.
  
  
  RESULTS
  K values (dental staining) increased in all groups when comparing T0 and T1. The effectiveness of the tested adjuncts was, in decreasing order: G1 (-3.11) > G2 (-2.97) > G3 (-1.28) > G4 (-1.19), not observing significant statistical differences (p < 0.05) between G1 and G2 and also between G3 and G4.
  
  
  CONCLUSIONS
  Protocols to remove photosensitizing dyes should be applied after PDT in order to minimize dental stain. The protocols tested in this study by using 2.5% NaOCl, associated or not with Endo-PTC cream, were effective in avoiding tooth staining caused by MB during PDT.
authors.affiliation: Department of Dentistry, University of Taubate, Taubate, São Paulo, Brazil.
authors.forename: Erica dos Santos
authors.initials: Edos S
authors.lastname: Carvalho
authors.forename: Isabel
authors.initials: I
authors.lastname: Mello
authors.forename: Silvio José
authors.initials: SJ
authors.lastname: Albergaria
authors.forename: Sandra Márcia
authors.initials: SM
authors.lastname: Habitante
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Lage-Marques
authors.forename: Denise Pontes
authors.initials: DP
authors.lastname: Raldi
mesh_terms: D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000528:radiation effects*; D004492:Edetic Acid / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D008751:Methylene Blue / Q000737:chemistry*; D010778:Photochemotherapy / Q000379:methods*; D010781:Photography; D017319:Photosensitizing Agents / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry; D012390:Root Canal Therapy / Q000379:methods*; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties
chemical_list: D017319:Photosensitizing Agents; D012388:Root Canal Irrigants; D000431:Ethanol; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D008751:Methylene Blue