This randomized controlled trial evaluates the effect of diode laser pre-treatment on the retention and caries prevention of giomer-based fissure sealants in young adults aged 17-22 years. The study compares sealant application with and without diode laser conditioning on molars with ICDAS 0-2 fissures over a 12-month follow-up period. Primary outcome is sealant retention using Simonsen's criteria, while secondary outcome is caries prevention using modified USPHS criteria. The study hypothesizes that diode laser pre-treatment may improve sealant retention and enhance caries prevention by modifying enamel surface characteristics and improving sealant penetration.

The protocol investigates whether diode laser pre-treatment can improve the clinical performance of a giomer-based fissure sealant in young adults. The study is designed as a two-arm randomized controlled clinical trial evaluating sealant retention and caries prevention over a 12-month period.

The background emphasizes that pits and fissures of posterior teeth are highly susceptible to caries, and fissure sealants are an evidence-based preventive approach. Giomer sealants combine the advantages of resin composites and glass ionomer materials through S-PRG filler technology, offering fluoride release and simplified application using self-etch primer systems. However, concerns remain regarding their long-term retention. Diode laser enamel pre-treatment is proposed to enhance enamel surface roughness, improve sealant penetration, and increase resistance to acid dissolution, potentially improving retention and caries prevention.

The study aims to compare giomer-based sealant application with and without diode laser pre-treatment in patients aged 17-22 years having deep retentive fissures with ICDAS scores 0-2 in second and third molars. Primary outcome is sealant retention assessed using Simonsen's criteria, while secondary outcome is caries prevention evaluated using modified USPHS criteria at baseline, 6 months, and 12 months.

The null hypothesis states that diode laser pre-treatment will not significantly affect retention rate or caries prevention compared with conventional application. The protocol includes detailed sample size calculation based on previous literature, resulting in 37 teeth per group after adjustment for dropouts. Statistical analysis will include chi-square and Cochran's Q tests with significance set at p ≤ 0.05.

Eligibility criteria include healthy young adults with good oral hygiene and absence of parafunctional habits. Teeth with fractures, existing restorations, secondary caries, developmental defects, or periodontal compromise are excluded.

Methodologically, participants are randomly allocated using opaque sealed envelopes. In the control group, self-etch primer is applied before placement of BeautiSealant. In the laser group, a 940-nm diode laser is first applied to the occlusal surface, followed by the same primer and sealant application protocol. All restorations are light-cured and clinically evaluated for voids and occlusion

Inclusion Criteria:

• Young adult Patients Aged 17-22.

  • Good oral hygiene (plaque index score 0 or 1).
  • Absence of abnormal occlusion habits (e.g. bruxism, nail biting, tooth clenching and mouth breathing).
  • Patients approving to participate in the study.

Exclusion Criteria:

• •Patients with known allergic or adverse reaction to the tested materials.

  • Systematic disease that may affect participation.
  • Xerostomic patients.