One hundred twenty previously extracted premolar teeth were used in this study. Teeth were divided into five groups of twenty-four each. The first group was treated with Copalite, the second with Portrait Veneer, the third with a polymeric adhesive coating material (Protecto), the fourth group with Nuva-Seal, and the fifth group served as a control. Orthodontic bands were selected and cemented to each tooth. The cement seal was then broken and teeth were thermocycled to simulate an in vivo condition. All teeth were then submerged in a decalcifying gelatin for 21 weeks. Every group was further broken into three equal subdivisions. Division A was to be submerged for 7 weeks, Division B in each group was to be submerged for 14 weeks, and Division C was to be submerged for 21 weeks. At each time interval, teeth were cleaned and examined for decalcification. Data were recorded and analyzed by means of the chi-square test. It was found that acid-etching materials protect the teeth against decalcification best. Among the acid-etching materials used, Nuva-Seal proved to be the best at protecting the teeth against decalcification for 21 weeks with this experimental design.