title: Shear bond strength of a sealant to contaminated-enamel surface: influence of erbium : yttrium-aluminum-garnet laser pretreatment.
abstract: BACKGROUND
  Salivary contamination is one of the factors that can disturb the sealing process and interfere in the longevity of pit and fissure sealants. Erbium : yttrium-aluminum-garnet (Er : YAG) laser could influence the bond strength of enamel and increase the acid resistance.
  
  
  OBJECTIVE
  To evaluate the influence of Er : YAG laser on the shear bond strength of a sealant to a salivary contaminated enamel surface.
  
  
  METHODS
  Twenty-four third molars had the roots sectioned 2 mm coronal to the cementoenamel junction. The crowns were mesiodistally sectioned providing 48 halves that were embedded in polyester resin. Enamel was flattened and a 2-mm diameter bonding area was demarcated. Specimens were randomly assigned to two groups according to the superficial pretreatment-37% phosphoric acid (A) and Er : YAG laser (80 mJ/2 Hz) + phosphoric acid (L), which were subdivided into two groups (N = 12), without salivary contamination (C) and with salivary contamination (SC). To contaminate the specimens, 0.25 mL of human fresh saliva was applied for 20 seconds and then dried. Fluroshield sealant was applied in all specimens. After storage, shear bond strength of samples were tested in a universal testing machine.
  
  
  RESULTS
  Means in MPa were: AC-14.61 (+/-2.52); ASC-6.66 (+/-2.34); LC-11.91 (+/-1.34); and LSC-2.22 (+/-0.66). Statistical analysis revealed that surfaces without salivary contamination and with acid treatment had the highest mean (p < 0.05). The group with salivary contamination treated by Er : YAG laser followed by phosphoric acid application presented the lowest bond values (p < 0.05).
  
  
  CONCLUSIONS
  The phosphoric acid etching under dry condition yielded better bonding performance. Er : YAG laser was not able to increase the effectiveness of conventional acid etching of enamel in the bond of sealants in both dry and wet conditions.
  
  
  CONCLUSIONS
  Under the conditions of this study, the conventional etching protocol (phosphoric acid without salivary contamination) is still preferable to laser-conditioning enamel surface prior to sealant application.
authors.affiliation: Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paolo (USP), São Paulo, Brazil.
authors.forename: Taísa Penazzo
authors.initials: TP
authors.lastname: Lepri
authors.forename: Aline Evangelista
authors.initials: AE
authors.lastname: Souza-Gabriel
authors.forename: Juliana Abdallah
authors.initials: JA
authors.lastname: Atoui
authors.forename: Regina Guenka
authors.initials: RG
authors.lastname: Palma-Dibb
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Silmara Aparecida
authors.initials: SA
authors.lastname: Milori Corona
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001840:Dental Bonding / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000187:drug effects / Q000528:radiation effects*; D045662:Dental Etching / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D053844:Lasers, Solid-State; D010895:Pit and Fissure Sealants; D011897:Random Allocation; D012463:Saliva / Q000528:radiation effects; D033081:Shear Strength; D013499:Surface Properties
chemical_list: D010895:Pit and Fissure Sealants