The study involved 54 adult patients between the ages of 18 and 50 years who had a posterior permanent tooth with a deep occlusal (Class I) carious lesion that extended to the inner third of the dentin (D3) and divided them into two equal groups randomly (N=27) according to the caries removal technique: group 1 (SE), and group 2 (SW). Then each main group was equally subdivided into three equal subgroups (n=9) according to the applied dentin dressing material as follows: Subgroup 1: Nano-silver compound (NSC), Subgroup 2: Chitosan-loaded nano hydroxy apatite (CS/N-HAp), Subgroup 3: Bioactive glass ionomer (N-BAG/GIC). At the first visit both groups received the same treatment of incomplete caries excavation, application of dentin dressing materials and sealing temporarily for 3-months with a glass ionomer cement (GIC). At the second visit the GIC reduced pulpally in (SE) group leaving 2 mm as base and completely removal the remaining carious lesion in (SW) group then re-application of same dentin dressing material on each tooth and GIC as a base. Finally, all cavities were restored with selective enamel etching technique, after which self-etch adhesive and Nano-filled composite resin are applied according to manufacturer instructions. The clinical and digital radiographic evaluations of the success and failure rates were performed at: baseline (7 days), 3, 12, and 18-months.

Inclusion Criteria:

1. Patients with first and second molars with occlusal deep carious lesions (Class I) extending to the inner third of dentin thickness on radiographic examination using (i-sensor H1, Woodpecker, China).
2. Teeth with a healthy response to the electrical pulp tester (DY 310, Denjoy Dental CO., LTD, China).
3. Teeth with the absence of spontaneous pain.
4. Teeth with a negative sensitivity to percussion.
5. Teeth with the absence of periapical lesions by a digital radiographic examination.
6. Clinically, all teeth were without any mobility.
7. Patients who will complete the procedure of follow up.
8. Patients who will sign the consent.

Exclusion Criteria:

1. Mutilated teeth or teeth with caries extending subgingivally.
2. Teeth with the existence of previous restorations.
3. Teeth with periodontal disease, any swelling, fistulas, signs of irreversible pulpitis or necrotic pulp.
4. Teeth with roots showing external or internal resorption.
5. Pregnant women.
6. Presence of any systemic disease.