There are many studies in the literature showing that the use of 5.25% NaOCl as an enamel deproteinization agent is successful in positively affecting adhesion by removing organic elements from both the enamel structure and the pellicle on the enamel surface before acid application. However, sodium hypochlorite is a strong oxidizing agent and has disadvantages such as the risk of reaction in the soft tissues of the mouth, bad odor and bad taste, especially if not used carefully in pediatric dentistry, which has led to the search for an alternative material.

Hypochlorous acid is produced by the body's immune system cells, neutrophilic polymorphonuclear leukocytes, as a result of oxidative reactions to overcome pathogenic microorganisms and fight infection. Recently, slightly acidic HOCl solutions, developed by electrolysis of NaOCl, have been widely used as disinfectants. Hypochlorous acid has been shown to significantly reduce the lipopolysaccharide concentration of Porphyromonas gingivalis compared to NaOCl and chlorhexidine and to be an agent tolerated by oral tissues. It has also been reported that HOCl used as a mouthwash does not produce any systemic side effects. In clinical dentistry, HOCl has been shown to be highly effective as a result of its antimicrobial and deproteinizing properties. HOCl, with its low acidity, is an antiseptic irrigant with extraordinary properties, not only exhibiting biocompatibility and low cytotoxicity, but also having rapid and highly effective antimicrobial activity in physiological concentration ran

Since there is no in vivo study in the literature evaluating the clinical success of the use of hypochlorous acid for deproteinization in fissure sealants, our planned study is the first in this regard.

Modified Simonsen Criteria Score 0 Fissure sealant is completely in the mouth and there is no new caries. Score 1 Partial loss of fissure sealant, no new caries. Score 2 Partial loss of fissure sealant and new caries. Score 3 Complete loss of fissure sealant, no new caries. Score 4 Complete loss of fissure sealant and new caries.

Edge Integrity Evaluation Criteria 0 The fissure sealant and tooth surface are intact and cannot be distinguished with a probe. 1 The edges of the fissure sealants can be distinguished with a probe. 2 There is a gap along the edge of the fissure sealant and deep cracks reaching the central fossa.

Marginal Coloration Evaluation Criteria 0 No color change between fissure sealant and tooth. 1 Color change in only one area. 2 Color change in many areas. 3 Severe color change indicating leakage.