AN INVESTIGATION OF POTENTIAL DESENSITIZING AGENTS IN THE DENTIN DISCMODEL - A SCANNING ELECTRON-MICROSCOPY STUDY

Cervical dentine sensitivity (CDS) may be defined as pain arising from exposed dentine. The prefix cervical indicates the location of the se nsitivity and/or its subsequent treatment. Currently the most accepted mechanism of intradental nerve activation associated with dentine sen sitivity appears to be hydrodynamic in nature. The concept of tubule o cclusion as a method of dentine desensitization is a logical conclusio n of the hydrodynamic theory. The authors employed the dentine disc mo del, qualitative scanning electron microscopy (SEM) and X-ray microana lysis to investigate whether selected desensitizing agents occlude den tinal tubule orifices. Strict control procedures have been used togeth er with various methods of application to apply these agents to human dentine discs. SEM was used to examine the degree of deposit left by t he various agents on disc surfaces and X-ray microanalysis was employe d to characterize the elemental composition of the deposit. Analysis o f selected agents, both prior to and after application on dentine disc s was performed for comparative purposes. The degree of retention of t he surface deposit upon rotation with saliva supernatant for 6 h was a lso studied. The results of this study indicated that ferric oxalate, the active ingredient of Sensodyne Sealant(R), which produced initial crystal-like structures, occluding almost all the tubule orifices was superior to potassium oxalate (Butler Protect(R)). Of the over-the-cou nter (OTC) desensitizing products tested, both silica- and calcium-bas ed abrasive components were observed both on the surface and within th e tubules, indicating a certain degree of therapeutic potential for th ese two components. These findings suggest that certain desensitizing agents have tubule occluding properties as observed in this in vitro s ystem which, in turn, may indicate a therapeutic potential in vivo.