Evaluation of human enamel permeability exposed to bleaching agents

  • Diego Horning State University of Ponta Grossa
  • Giovana Mongruel Gomes State University of Ponta Grossa
  • Bruna Fortes Bittencourt State University of Ponta Grossa
  • Lucas Manuel Ruiz State University of Ponta Grossa
  • Alessandra Reis State University of Ponta Grossa
  • Osnara Maria Mongruel Gomes State University of Ponta Grossa

Abstract

Aim: To evaluate the human enamel permeability after different external bleaching techniques. Methods: The coronal portions of 20 maxillary human incisors were covered with an acid resistant varnish, except the labial surface, to prevent dye penetration of silver nitrate. The specimens were divided randomly into four groups (n=5) according to the bleaching treatments: Group 1 (G1) - without bleaching agent (control group), Group 2 (G2) - 35% hydrogen peroxide (HP) – one session of three 10-min applications, Group 3 (G3) - 35% HP – 2 sessions of three 10-min applications, and Group 4 (G4) - 6% HP – 14 days (1h/day). G1 was exposed to artificial saliva only and in the other groups the bleaching agents were applied following the manufacturers’ recommendations. After bleaching, teeth were immersed in a 50% silver nitrate solution for 2 h and photodeveloped for 16 h. Then, three longitudinal slices of each tooth were photographed by an optical microscope (100x). The degree of dye penetration was analyzed in the middle third of the dental crowns using a 0 to 4 score system (0= no dye penetration, 1= less than half the enamel thickness, 2= half of the enamel thickness, 3= full extent of enamel without reaching the dentin, and 4= tracer agent reaching dentin). The data were analyzed statistically by the KruskalWallis and Dunn tests (α=0.05). Results: The median (1st/3rd interquartiles) ranges were: G1: 0(0/0), G2: 2(2/3), G3: 3(3/3) and G4: 3(3/3). G2, G3 and G4 showed significantly higher dye penetration compared with G1 (p=0.0017). Conclusions: The use of bleaching agents increased dental enamel permeability, regardless of the bleaching technique.

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Author Biographies

Diego Horning, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Giovana Mongruel Gomes, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Bruna Fortes Bittencourt, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Lucas Manuel Ruiz, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Alessandra Reis, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Osnara Maria Mongruel Gomes, State University of Ponta Grossa
Department of Restorative Dentistry, Dental School, State University of Ponta Grossa, Ponta Grossa, PR.
Published
2015-10-16
How to Cite
Horning, D., Gomes, G. M., Bittencourt, B. F., Ruiz, L. M., Reis, A., & Gomes, O. M. M. (2015). Evaluation of human enamel permeability exposed to bleaching agents. Brazilian Journal of Oral Sciences, 12(2), 114-118. https://doi.org/10.20396/bjos.v12i2.8641083
Section
Article

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