A 20-year-old patient complains about feeling spontaneous undurable localised pain in the 26 tooth for one day. Objectively: the 26 tooth has a deep Black's class I carious cavity. Dentine of its walls and floor is unpigmented, softened, carious cavity is not communicating with the tooth cavity. Probing causes acute pain focused at a single point, cold test induces long-lasting pain. What method of treatment is the most appropriate in this case?