Effect of bleaching agents on enamel surface of bovine teeth: A SEM study.
BACKGROUND
This study aimed to evaluate changes in the enamel surface of bovine teeth after whitening with exogenous bleaching agents: 10% carbamide peroxide (group 1), 16% carbamide peroxide (group 2) and 35% hydrogen peroxide activated by a light-emitting diode (LED) (group 3). The evaluations were performed by scanning electron microscopy (SEM).


METHODS
Ninety bovine teeth were divided into five groups (n = 18). The bleaching agents 10% and 16% carbamide peroxide were applied for eight hours a day for 14 consecutive days. The third agent, LED-activated 35% hydrogen peroxide, was used four times at seven-day intervals. Each of the four time points consisted of three applications of 10 minutes each. A 37% phosphoric acid solution and artificial saliva were used as positive and negative controls, respectively.


RESULTS
The evaluations by SEM showed changes in the enamel surfaces of the specimens. Based on the Mann-Whitney statistical test, the data showed significant differences (p<0.05) between groups 1 and 2 and between groups 2 and 3. However, no significant difference (p>0.05) was observed between groups 1 and 3.


CONCLUSIONS
Based on these results, it can be concluded that bleaching agents can cause changes in the structure of tooth enamel and that these changes are related to the concentration and the duration of contact with the tooth surface.Key words:Bovine teeth, carbamide peroxide, enamel, hydrogen peroxide, scanning electronic microscopy.
DDS, MS, Graduate student, Departament of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Brasil.
Ana-Cristina
AC
Pimenta-Dutra
DDS, MS, Graduate student, Departament of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Brasil.
Rodrigo-de Castro
RC
Albuquerque
DDS, MS, PhD, Professor, Centro Universitário Newton Paiva, Belo Horizonte, Brazil.
Luís-Fernando-Dos Santos-Alves
LS
Morgan
DDS, MS, PhD, Professor, Centro Universitário Newton Paiva, Belo Horizonte, Brazil.
Geraldo-Magela
GM
Pereira
DDS, MS, PhD, Professor, Departament of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Brasil.
Eduardo
E
Nunes
DDS, MS, PhD, Professor, Departament of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Brasil.
Martinho-Campolina-Rebello
MC
Horta
DDS, MS, PhD, Professor, Departament of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Brasil.
Frank-Ferreira
FF
Silveira