ABSTRACT
This study was designed to evaluate one of the commonly used scoring systems -Score I- [categories from 0-5] to other two suggested scoring systems -Score II and III- [categories from 0-1 and 0-2 respectively], to test the degree of dye penetration for leakage studies. Class V cavities were prepared on 100 extracted human upper central incisors and filled with light cured composite. Herculite, and high copper amalgam. Tytin. All teeth were immersed in sodium fluorescein dye to test the degree of dye penetration. The results revealed that the suggested score II is very easy, simplified and representitive but not indicative regarding the severity of dye penetration as score I. Score III are indicative and obvious discussion can be obtained rather than score I. For any leakage study the use of non parametric measurement is preferable than parametric ones