The Study Aims to Compare the Effectiveness of Mesoporous Bioactive Glass-containing Adhesives vs Conventional Universal Adhesives on the Clinical Performance Composite Restorations Through Promoting Dentin Remineralization After Selective Caries Removal Over a Two-year Follow-up

This study is a two-year, double-blind, randomized controlled clinical trial designed to compare the clinical performance and radiographic outcomes of a mesoporous bioactive glass adhesive (Hi-Bond Universal) with a conventional universal adhesive (OptiBond Universal) in Class II carious lesions. The trial will enroll 80 participants aged 22 to 42 years, recruited from the Outpatient Clinic of the Conservative Dentistry Department at Cairo University.

Eligible participants presenting with ICDAS 5 and 6 carious lesions in posterior permanent teeth will be randomly assigned to one of two treatment groups. The intervention group will receive the Hi-Bond Universal adhesive, a bioactive glass-modified adhesive intended to promote dentin remineralization and reduce postoperative hypersensitivity through calcium and phosphate ion release. The control group will be treated with OptiBond Universal, a conventional adhesive providing mechanical bonding without bioactive properties.

Clinical outcomes will be evaluated using the FDI World Dental Federation criteria, focusing on functional properties such as fracture resistance, marginal adaptation, and retention. Radiographic assessments will quantify dentin remineralization using digital grayscale analysis. Hypersensitivity will be recorded using a patient-reported Likert scale at baseline, 6, 12, 18, and 24 months.

The primary outcome is the functional integrity of the restorative material, assessed at 24 months. Secondary outcomes include the presence of marginal caries, postoperative hypersensitivity, and radiographic evidence of dentin remineralization. Data will be analyzed using appropriate statistical methods to determine differences between the two adhesive systems.

Inclusion criteria

• Adult patients aged 22 to 42 years.

Presence of Class II carious lesions in posterior permanent teeth (ICDAS 5 & 6).

Radiographic evidence of caries extending to 50% of dentin with a radiopaque layer between the lesion and pulp chamber.

Teeth with normal pulp vitality confirmed through cold pulp sensibility test.

Teeth with no periapical pathosis on radiographic examination.

Good oral hygiene as determined by the attending clinician.

Willingness to sign the informed consent and comply with the 2-year follow-up protocol.

Cooperative patients who can attend all follow-up visits.

Exclusion criteria

• Allergy to any of the restorative materials (OptiBond Universal or Hi-Bond Universal).

Patients currently undergoing orthodontic treatment with fixed appliances.

Pregnant women or those planning pregnancy during the study period.

Patients with systemic diseases that could interfere with dental treatment (e.g., uncontrolled diabetes, cardiovascular diseases).

Use of analgesics or medications that could mask postoperative sensitivity.

Teeth with previous restorations or treatment in the target area.

Teeth exhibiting spontaneous pain or lingering pain after sensitivity testing, indicating irreversible pulpitis.

Negative response in cold pulp sensibility test, indicating pulp necrosis.

Teeth with periapical radiolucencies or signs of infection.

Mobile teeth due to periodontal disease or trauma.

Teeth with extensive structural damage, such as cusp fractures or deep cracks.

Patients unable to comply with the follow-up schedule.