A modified technique for removal of prismless enamel in primary teeth : a scanning electron microscopy study

Abstract

Acid etching of teeth allows for attachment of resins to enamel for preventive dentistry, repair of fractured anterior teeth, direct bonding of orthodontic brackets and many other useful procedures in both adults and children. However, it has been shown that primary tooth enamel has a pronounced prismless layer compared to enamel of permanent teeth. The enamel of primary teeth is more acid resistant and tends to interfere with the development of well developed prism-end-patterns needed for resin attachment. Gwinnett (1973) found that mechanical disking could be used to remove the prismless enamel layer and enhance the development of etching patterns. The purpose of this investigation was to determine whether the acid etch procedure can be made more effective on primary tooth enamel through the use of simple mechanical pretreatment. For that purpose, forty teeth were divided into four groups. Teeth in Group I were etched for two minutes with 37% phosphoric acid and then prepared for scanning electron microscopy. The same procedure was followed for Group II. After sealing, the enamel was totally dissolved and the negative replica viewed in a SEMicograph. The prismless layer of the teeth in Group III were removed by (1) paper disk, (2) green stone (3) initial two minutes etching followed by the use of a green stone and pumice. The teeth were then etched again by applying 37% phosphoric acid for one minute. In Group IV, the same procedure as in Group III was applied, followed by the negative image technique・ The results indicated that the method of Group III, sub division C, demonstrated the best result. The specimens established a good surface uniformity and the length of tags was uniform as demonstrated by Group IV, sub division C. Control specimens in Group I did not show these features. They lacked uniformity and a clearly definable etching pattern.