To evaluate the clinical performance of High-Viscosity Glass Ionomer (EQUIA) versus Silver Diamine Fluoride combined with Potassium Iodide (Riva Star) and Sliver Diamine Fluoride (SDF) under High-Viscosity Glass Ionomer (EQUIA) in deep class I carious lesions, over a period of one year follow-up. The null hypothesis tested in this study, that in deep class I carious lesions, the High-Viscosity Glass Ionomer (EQUIA) versus Silver Diamine Fluoride combined with Potassium Iodide (Riva Star) and Sliver Diamine Fluoride (SDF) under High-Viscosity Glass Ionomer (EQUIA) will show the same clinical performance.

A sample of adults with an age range of 18-40 years old, having a permanent molar with deep class I carious lesions, according to the international caries detection and assessment system (ICDAS), occlusal caries that scored 4 (underlying dark shadow from dentin), or 5 (Distinct cavity with visible dentin), will be selected from the patients attending at the Conservative and Esthetic Dentistry Department Clinic, Faculty of Dentistry, Cairo University, and those who meet the study inclusion criteria will be recruited.

All selected 42 permanent molars will be randomly equally allocated into three groups according to the material used. Group I (n=14) Silver Diamine Fluoride combined with Potassium Iodide (Riva Star) under High-Viscosity Glass Ionomer (EQUIA), Group II (n=14) Silver Diamine Fluoride (SDF) both under High-Viscosity Glass Ionomer (EQUIA), and Group III (n=14) High-Viscosity Glass Ionomer (EQUIA).

Steps in Short:

1. Recruitment of the patients and full examination with diagnosis.
2. Informed consent taking for the eligible participants to participate in the study.
3. Randomization and allocation into three groups.
4. Application of the intervention 1; Silver Diamine Fluoride combined with Potassium Iodide (Riva Star). Intervention 2; Silver Diamine Fluoride (SDF). Both under High-Viscosity Glass Ionomer (EQUIA). The comparator; High-Viscosity Glass Ionomer (EQUIA). All materials were manipulated according to the manufacturers' instructions.
5. Baseline data collection of the clinical evaluation of the restorations using FDI criteria.
6. Follow up at 3, 6, and 12 months for data collection of the clinical evaluation of the restorations using FDI criteria.

Inclusion Criteria:

1. Patients with deep class I carious lesions in molars, according to the international caries detection and assessment system (ICDAS), occlusal caries that scored 4 (underlying dark shadow from dentin), or 5 (Distinct cavity with visible dentin).
2. Adults males or females.
3. Age: 18-40 years old.
4. Good Oral hygiene.
5. Co-operative patients, approving to participate in the study.
6. Teeth planned to be restored should be vital.
7. Presence of favorable occlusion.

Exclusion Criteria:

1. Patients having severe systemic diseases, allergies, or adverse medical histories.
2. Patients complaining of sever or active periodontal disease.
3. Lack of compliance.
4. Teeth diagnosed with irreversible pulpitis.
5. Non vital teeth.
6. Heavy occlusion.

after 1 year.

The operator will not be blinded due to differences between both materials.