What agent is used to achieve haemostasis before placing the capping material in vital pulp therapy?

Correct answer: D. Sodium hypochlorite

• A. Calcium hydroxide is a capping MATERIAL, not a haemostatic agent. It is placed after bleeding has been controlled, and has largely been superseded by bioceramic materials such as MTA and calcium silicate cements for direct pulp capping.
• B. Ferric sulfate is used for haemostasis in primary tooth pulpotomy and in gingival retraction, but it forms a ferric ion–protein coagulum that interferes with the seal and adds no disinfecting benefit at the exposure site.
• C. Epinephrine pellets achieve haemostasis by vasoconstriction, but they leave the contaminated superficial pulp layer in place and can produce a rebound hyperaemia. They are not the current standard for this application.
• D. CORRECT. Sodium hypochlorite (typically 1.5% to 6%) applied on a moistened cotton pellet for one to ten minutes is the contemporary standard for pulpal haemostasis in vital pulp therapy. It does more than stop bleeding — it disinfects the exposure site, dissolves the fibrin clot and the superficial layer of damaged, biofilm-contaminated pulp tissue, and leaves a clean surface for the bioceramic capping material to contact. Persistent bleeding beyond about five minutes signals irreversibly inflamed tissue and is an indication to remove more pulp or convert to pulpectomy.

Note: Vital pulp therapy sequence: isolate with rubber dam → remove caries → disinfect → achieve haemostasis with NaOCl → place a bioceramic (MTA or calcium silicate) → seal immediately with a definitive restoration. The bacterial seal is what determines success, more than the choice of capping material.