After administering a questionnaire to collect demographic data (including gender, age, education level, and frequency of dental visits) and MDAS scores, patients with an MDAS score of 10 or higher, indicating moderate to high dental anxiety, will be randomly allocated into three groups (n = 25 per group). Standard restorative treatment will be performed on the selected patients under music therapy.

A single carpule of local anesthetic without vasoconstrictor will be administered to each patient using a disposable dental syringe. Following anesthesia, caries removal and cavity preparation will be performed. The restorative procedure will then commence. All procedures will be performed by the same clinician following a standardized protocol. Selective enamel etching will be performed with phosphoric acid for 30 seconds, followed by rinsing and gentle drying. Universal dental adhesive will be applied and polymerized according to the manufacturer's instructions. Subsequently, the prepared cavities will be restored with a resin composite, which will be light-cured for 20 seconds using an LED curing unit. Upon completion of finishing and polishing, the total duration of the restorative procedure will be recorded. Only one restoration will be performed for each patient.

Assessment of Physiological and Salivary Biomarkers In this study, systolic and diastolic blood pressure (SBP and DBP), oxygen saturation (SpO₂), heart rate (HR), salivary cortisol levels, salivary alpha-amylase (sAA) levels, and MDAS scores will be measured twice-once initially and once after the restorative procedure. Blood pressure will be recorded using a manual sphygmomanometer on the patients' right arms at heart level, and results will be expressed in mmHg. HR and SpO₂ will be measured with a finger-type portable pulse oximeter placed on the right index finger.

Unstimulated saliva samples will be collected from each participant just before and immediately after the procedure. Patients will be instructed to expectorate into sterile disposable tubes, ensuring the samples are free of blood contamination. To control for circadian fluctuations in cortisol and sAA levels, all samples will be collected between 9:00 and 12:00 a.m. The collected samples will be immediately stored at -80 °C until analysis.

A blinded researcher will perform all biochemical analyses after the completion of patient treatments. Samples will be thawed and centrifuged at 3,000 × g for 10 minutes. Cortisol concentrations will be determined using an enzyme-linked immunosorbent assay (ELISA) kit, while salivary alpha-amylase activity will be quantified with a colorimetric enzymatic assay. Absorbance values will be measured at a wavelength of 450 nm, and the results will be expressed in nanograms per milliliter (ng/ml) for cortisol and units for alpha-amylase.

Inclusion Criteria:

• Systemically healthy adults aged 18-40 years.
• Presence of D2 dentin caries confirmed by clinical and radiographic examination, characterized by radiolucency limited to the outer half of the dentin without pulpal or periapical pathology,
• Indication for single-session restorative treatment,
• Individuals with moderate-to-high dental anxiety according to the Modified Dental Anxiety Scale (MDAS), defined as a total score ≥10 (moderate: 10-18; high: ≥19).
• Ability and willingness to complete questionnaires and comply with study procedures.

Exclusion Criteria:

• deep dentin or pulpal involvement lesions, secondary caries, cracks, or fractured teeth,
• Acute or spontaneous dental pain, percussion sensitivity, or periapical pathology,
• Individuals with an MDAS total score ≤ 9 (no/low dental anxiety) were excluded.
• Hearing impairment or contraindications for music therapy,
• Psychiatric medication use or a diagnosed psychiatric disorder affecting anxiety response,
• Pregnant or breastfeeding individuals.