All specimens were coated with acid-resistant varnish Revlon, France, with the exception of one area, measuring 3.0 x 6.0 mm, located at the labial or lingual surface Figure 2.
Cada espécimen fue cubierto con barniz ácido resistente Revlon, Francia, a excepción de un área de 3.0 x 6.0 mm en la cara labial o lingual Figura 2.