In vitro Study Regarding the Effect of Different Types of Etching Acids on the Morphology and Chemical Content of the External Surface of Enamel Carious Lesion on Primary Teeth

摘要

The aims of this study were to evaluate the changes in surface morphology and in chemical composition of the artificial carious enamel lesion after etching with different types of etching acids. 25 extracted primary canines and molars were sectioned in mesio-distal direction. The external surface of the enamel was covered with a varnish resistant to acid action excepting a square of 2 mm x 2 mm, situated in the central area of the buccal and lingual faces. Artificial enamel carious lesions were induced. The 50 prepared sections were randomly divided into 5 groups. Control group included 10 enamel samples not subject to acid etching. Each of the rest of 4 study groups included 10 enamel samples etched for 15, 30, 60s with 37% phosphoric acid gel respectively, 2 minutes with 15% hydrochloric acid gel. The samples were then analyzed using a scanning electronic microscope coupled with a EDX detector. Phosphoric acid and hydrochloric acid affect the surface morphology of the carious enamel. Etching with 37% phosphoric acid for 15 or 30 s lead to similar morphological changes on artificial enamel carious lesion. A decrease of calcium and phosphorous ions content were recorded after etching with phosphoric acid and hydrochloric acid, as a result of enamel dissolution.