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, Group B: Air abrasion, Group C: Ultrasonic preparation, Group D: Air abrasion followed by acid-etching preparation, and Group E: Ultrasonic followed by acid-etching preparation. Measurements of sealant marginal adaptation shear bond strength, and resin penetration.
Results: air abrasion or ultrasonic followed by acid etching, and acid etching alone exhibited less microleakage. acid-etching alone. ultrasonic alone resulted in a significant increase in the resin retention when compared with air abrasion alone. However, the use of ultrasonic in combination with acid etch resulted in an insignificant increase in the resin retention when compared with air abrasion in combination with acid etch. Conclusion: acid etching remains the most effective and simplest technique in sealants' success. The use of air abrasion followed by acid etching can be recommended to maintain an adequate seal.