Objectives: the present study was conducted to evaluate the effect of Two Different Invasive Tooth Surface Preparation Techniques on Penetration, Marginal Adaptation, and Retention of Pit and Fissure Sealant.Subjects and methods: A total of 60 permanent mandibular molars were divided into five equal main groups according to the pits and fissure preparation protocol as follow: Group A: Acid-etching...