Effects of Selected Primers and Vanishes on Open Dentine Tubules: An SEM Study

Dentine sensitivity (DS) is a common painful condition affecting teeth. The exact mechanism of transmission of an environmental stimulus across dentine is not fully understood; currently the most accepted theory is the hydrodynamic theory as proposed initially by Brannstrom. Treatment has been concentrated on either reducing the dentine fluid flow by occlusion of tubule openings, or altering the pulpal sensory nerve activity preventing transmission of pain to the central nervous system. Aims and Method: The aims of the present in vitro study were to examine the dentine tubule occluding and penetrating properties of selected in-office desensitizing agents (varnishes and primers) using scanning electron microscopy and a dentine disc model. Results: Of the products examined, the fluoride varnishes, Bifluoride 12 and Duraphat, and Cervitec (a chlorhexidine containing varnish) were effective in both occluding and penetrating the dentine tubules. The results from All Bond 2, One Step and Scotchbond primers were superior to those of HEMA group primers, Gluma 3, Gluma CPS and Solobond Plus. Conclusions: These findings suggest a mechanism for the action of these potential desensitising agents and suggest that the tubule penetrating properties may play a role in the longevity of their retention on the tooth. Investigation of surface coverage and tubule penetrating characteristics are both necessary in order to fully evaluate in vitro the desensitising potential of agents claimed to reduce Dentine Sensitivity.