The purposes of this study were to evaluate die effect of sodium chloride and potassium oxalate and to observe the relationship between the dentinal hypersensitivity and surface characteristics such as dentinal tubule size and number. This study included 20 teeth which were scheduled for extraction and had no pulpal disease. These teeth were divided into Root planing group, EDTA group, NaCl group and Oxalate group. Dentinal hypersensitivity is measured by tactile, pressured air and cold water using NRS (Numerical Rating Scales). Teeth were extracted under local anesthesia and each specimen was sectioned to a size about 3 × 5 mm and was examined under the scanning electron microscope (×2,000)

The results were as follows,

1. The EDTA group exhibited significantly increased dentinal hypersensitivity comparing with the other groups.

2. The NaCl and Oxalate groups showed significantly reduced dentinal hypersensitivity comparing with the EDTA group.

3. As a method for dentinal hypersensitivity measurement, it was presumed that tactile sensitivity test was not sensitive method but air blast test and cold water test were adequate method.

4. In a SEM study, the root planing group exhibited amorphous smear layer and showed no dentinal tubule orifice, but the EDTA group showed the large number of dentinal tubules. On the other hand, the NaCl and Oxalate groups did not show exposed dentinal tubules. The NaCl group showed more rough root surface than the EDTA group, anti the Oxalate group showed many participates to be presumed as calcium oxalate particle.

As the results from this study, root planing couldn't expose the dentinal tubule and NaCl and potassium oxalate occluded exposed dentinal tubule effectively. Dentinal hypersensitivity has close relationship with the exposure of dentinal tubules, especially with it's size and number.