This randomized controlled clinical trial evaluates whether adjunctive 808-nm diode laser therapy after direct pulp capping reduces postoperative pain and dentin hypersensitivity compared with conventional Biodentine treatment. Sixty teeth from fifty-six participants with carious pulp exposure were randomly allocated into two treatment groups. Postoperative pain, dentin hypersensitivity, and 6-month clinical success rates were assessed.

Direct pulp capping (DPC) is a vital pulp therapy procedure intended to preserve pulp vitality and stimulate reparative dentin formation after pulp exposure. The clinical success of DPC depends on effective sealing of the exposure site, bacterial control, and maintenance of pulpal health. Bioactive tricalcium silicate-based materials such as Biodentine have demonstrated favorable biological and mechanical properties and are widely used as pulp-capping agents because of their biocompatibility, sealing ability, and dentin-bridge induction potential.

Despite the favorable outcomes of modern pulp-capping materials, postoperative pain and dentin hypersensitivity remain common complications following DPC. These symptoms may negatively affect patient comfort, treatment acceptance, and short-term clinical outcomes. Adjunctive use of diode laser therapy has been proposed to improve the biological environment of the exposed pulp by providing hemostasis, antimicrobial action, and photobiomodulation. Experimental and clinical evidence suggests that diode laser irradiation may reduce inflammation, stabilize cell membranes, improve microcirculation, and enhance cellular metabolism through increased adenosine triphosphate (ATP) synthesis, thereby reducing postoperative discomfort and promoting tissue healing.

However, evidence regarding the effectiveness of diode laser therapy as an adjunct to DPC remains limited, particularly due to variations in laser parameters, treatment protocols, and pulp-capping materials among previous studies. Therefore, this randomized controlled clinical trial was designed to evaluate the clinical effectiveness of adjunctive 808-nm diode laser therapy following direct pulp capping using Biodentine.

A total of 60 teeth from 56 participants diagnosed with carious pulp exposure and fulfilling the eligibility criteria were included. Eligible teeth were randomly allocated into two groups using a computer-generated 1:1 randomization sequence with allocation concealment by sequentially numbered, opaque, sealed envelopes (SNOSE). In the control group, direct pulp capping was performed using Biodentine following conventional hemostasis and disinfection procedures. In the experimental group, adjunctive diode laser therapy (808 nm) was applied for hemostasis and disinfection prior to Biodentine placement, using standardized irradiation parameters.

The primary outcomes of the study are postoperative pain intensity and dentin hypersensitivity. Postoperative pain is assessed using the Numerical Rating Scale (NRS, 0-10) and the duration until complete pain resolution is recorded. Dentin hypersensitivity is evaluated at 1, 3, and 6 months using a cold stimulus and NRS scoring. The secondary outcome is the clinical success rate at 6 months, determined by clinical and radiographic criteria including pulp vitality, absence of spontaneous pain, absence of tenderness to percussion, and absence of radiographic periapical pathology.

The study hypothesizes that adjunctive diode laser therapy will significantly reduce postoperative pain and dentin hypersensitivity following direct pulp capping compared with conventional Biodentine treatment, while maintaining comparable clinical success rates at 6 months.

Inclusion Criteria:

• Participants aged 10 to 58 years.
• Teeth with pulp exposure caused by caries removal.
• Vital teeth confirmed by clinical pulp vitality tests (cold and heat tests) and radiographic examination.
• No history of spontaneous pain; only mild or tolerable discomfort to cold stimuli.
• Pulp exposure less than 2 mm in diameter.
• Normal radiographic findings with no periapical pathology.
• Bleeding controllable within 10 minutes.
• Written informed consent obtained from participants or legal guardians.

Exclusion Criteria:

• Pulp exposure caused by trauma or occlusal wear.
• Teeth unsuitable for restoration, including subgingival fractures or vertical root cracks.
• Clinical signs of irreversible pulpitis, abscess, or sinus tract.
• Uncontrollable bleeding after 10 minutes of saline pressure or laser hemostasis.
• Previous use of analgesics before treatment.
• Multiple pulp exposures in the same dental arch.

De-identified individual participant data (IPD) underlying the results reported in this study will be shared, including demographic characteristics, postoperative pain scores, dentin hypersensitivity scores, and clinical follow-up outcomes. All personal identifiers will be removed to protect participant confidentiality.

Data will be available beginning 6 months following publication and will remain available for 5 years thereafter.

Access will be provided to qualified researchers who submit a methodologically sound proposal for secondary analyses or meta-analysis. Requests should be directed to the corresponding author by email and will be reviewed by the study investigators.

Due to the nature of the intervention, blinding of participants and care providers was not feasible because diode laser application was visible and audible during treatment. However, the outcome assessor responsible for evaluating postoperative pain, dentin hypersensitivity, and clinical follow-up outcomes was blinded to group allocation throughout the study. All assessment forms were coded by participant ID without treatment information, and participants were instructed not to disclose their treatment assignment during follow-up visits.