This study aims to evaluate and compare the clinical performance of pre-etched bioactive fissure sealants to conventional RBFS in permanent molars affected by MIH in terms of retention, marginal integrity, caries prevention effect, and sensitivity.

Molar Incisor Hypomineralization (MIH) poses a significant clinical challenge in pediatric dentistry due to enamel fragility, hypersensitivity, and increased susceptibility to caries. While conventional resin-based fissure sealant (RBFS) is the gold standard fissure sealant material for occlusal caries, its performance on hypomineralized enamel remains suboptimal. Bioactive sealants are newly developed materials that promote remineralization and utilize both mechanical and chemical adhesion; however, they demonstrate poor retention when used with their self-etching primer. Bioactive sealants with phosphoric acid pre-etching may offer improved clinical outcomes for MIH-affected teeth. This study aims to evaluate and compare the clinical performance of pre-etched bioactive fissure sealants to conventional RBFS in permanent molars affected by MIH in terms of retention, marginal integrity, caries prevention effect, and sensitivity. Participants will be randomly allocated to receive either a bioactive sealant with phosphoric acid pre-etching or conventional RBFS. Clinical evaluations will be performed at 3-, 6-, and 12- months post-application using Modified United States Public Health Service (USPHS) criteria to assess retention, marginal adaptation, and secondary caries formation. Pre and postoperative sensitivity will be measured using the Schiff Cold Air Sensitivity Scale (SCASS).

Inclusion Criteria:

• 6-12-year-old patients with at least one fully erupted first permanent molar (FPM) diagnosed with MIH defects (White, creamy, or yellow to brownish opacities greater than one millimetre) without posteruptive enamel breakdown or caries (ICDAS code 0 or 1).
• Non -contributory medical history
• Children must exhibit sufficient cooperation for treatment.
• FPMs status of eruption must allow for proper isolation. Exclusion Criteria:-
• Medically compromised patient.- Partially erupted MIH first permanent molars that could not be sufficiently isolated.
• Carious molars.
• Restored MIH molars.
• Sealed MIH molars.
• MIH molars with extensive enamel breakdown that requires restoration.
• MIH molars planned for extraction (compensatory or balancing extraction) as part of elective extraction plan of MIH molars with poor long-term prognosis.
• Molars affected with other enamel defects ((e.g., amelogenesis imperfecta or fluorosis)
• Non-MIH affected molars.
• Parents did not consent for treatment.
• Child not sufficiently cooperative for treatment.