Dental caries is a highly prevalent disease in children. Contemporary caries management emphasizes minimally invasive approaches that aim to arrest or reverse non-cavitated lesions rather than remove tooth structure. This randomized clinical trial aims to evaluate the effects of different remineralization agents on the progression of non-cavitated approximal carious lesions in primary teeth.

The study will be conducted in children aged 4-10 years presenting with non-cavitated approximal carious lesions in primary molars. Participants will be randomly assigned to treatment groups receiving silver diamine fluoride (SDF), a self-assembling peptide (P11-4), and/or 5% sodium fluoride (NaF) varnish. Materials will be applied according to manufacturers' instructions.

Lesion progression will be assessed using standardized bitewing radiographs obtained at baseline and follow-up visits. Radiographic evaluations will be performed by blinded investigators. In addition, potential tooth color changes associated with the treatments will be quantitatively measured using a spectrophotometer based on the CIE Lab* system at predefined follow-up intervals.

The findings of this study are expected to provide clinically relevant evidence regarding the effectiveness and aesthetic outcomes of contemporary non-invasive caries management strategies in primary teeth.

This study is designed as a randomized, parallel-group clinical trial investigating the effects of different remineralization agents on non-cavitated approximal carious lesions in primary teeth.

The study population will consist of children aged 4-10 years with at least two non-cavitated approximal carious lesions (radiographically classified at the enamel or outer dentin level) in primary molars. After baseline clinical and radiographic examinations, eligible teeth will receive preventive treatment interventions.

Participants will be randomly allocated to treatment groups. Interventions include silver diamine fluoride (SDF), a self-assembling peptide (P11-4), and 5% sodium fluoride (NaF) varnish. All materials will be applied following manufacturers' recommendations and standard clinical procedures. Repeat applications will be performed at scheduled follow-up visits.

Lesion progression will be evaluated using standardized bitewing radiographs taken at baseline and follow-up periods. Radiographic assessments will be performed independently by blinded examiners using predefined scoring criteria. Changes in lesion status over time will be categorized as regression, stability, or progression.

To assess potential aesthetic effects of the treatments, tooth color measurements will be performed using a spectrophotometer under standardized conditions. Color parameters will be recorded according to the CIE Lab* color system at baseline and follow-up visits.

Statistical analyses will be conducted to evaluate differences in lesion progression and color changes between treatment groups. Reliability of radiographic assessments will be evaluated using appropriate agreement statistics.

This study aims to generate clinical evidence regarding the effectiveness of minimally invasive remineralization strategies for managing non-cavitated approximal carious lesions in primary teeth.

Inclusion Criteria:

• Children aged 4-10 years
• Presence of at least two non-cavitated proximal caries lesions in primary teeth
• Radiographic detection of lesions classified as E1, E2, or D1
• Absence of systemic disease
• Cooperative patients
• Written informed consent obtained from parents or legal guardians

Exclusion Criteria:

• Presence of restorations on study teeth
• Deep dentin caries (D2 or D3)
• Cavitated lesions
• Uncooperative patients
• Inability to attend follow-up visits

Due to institutional policies and ethical considerations regarding pediatric patient confidentiality, individual participant data (IPD) will not be shared.

In this split-mouth randomized clinical trial, the outcome assessor was blinded to the lesions' allocation to remineralization agents.