Comparative evaluation of NovaMin desensitizer and Gluma desensitizer on dentinal tubule occlusion: a scanning electron microscopic study

Abstract

Purpose: In this study, the effect of calcium sodium phosphosilicate (NovaMin) desensitizing agent, which is a powder-based system, and hydroxyethyl methacrylate and glutaraldehyde (Gluma desensitizer), which is liquid-based system, on dentinal tubule occlusion was analyzed by scanning electron microscope. The effects of the above two along with one control group were compared to determine the more effective method of sealing the dentinal tubules after initial application.

Methods: Twenty specimens were allocated to each of 3 groups: Control, Gluma desensitizer, and NovaMin. Two additional samples were also prepared and treated with Gluma and NovaMin; these samples were longitudinally fractured. The specimens were prepared from extracted sound human premolars and were stored in 10% formalin at room temperature. The teeth were cleaned of gross debris and then sectioned to provide one to two dentin specimens. The dentin specimens were etched with 6% citric acid for 2 minutes and rinsed in distilled water. Control discs were dried, and the test discs were treated with the desensitizing agents as per the manufacturer's instructions. The discs as well as longitudinal sections were later analyzed under the scanning electron microscope. The proportions of completely occluded, partially occluded, and open tubules within each group were calculated. The ratios of completely and partially occluded tubules to the total tubules for all the groups was determined, and the data was statistically analyzed using nonparametric tests and statistical significance was calculated.

Results: NovaMin showed more completely occluded tubules (0.545±0.051) while Gluma desensitizer showed more partially occluded tubules (0.532±0.075). The differences among all the groups were statistically significant (P≤ 0.05).

Conclusion: Both materials were effective in occluding dentinal tubules but NovaMin appeared more promising in occluding tubules completely after initial application.

Keywords: Dentin sensitivity; Gluma desensitizer; NovaMin; Scanning electron microscopy.

Figure 1

Morphology of dentinal tubules treated with distilled water (control), seen under scanning electron microscope (×3,000).

Figure 2

Morphology of dentinal tubules treated with Gluma desensitizer, seen under scanning electron microscope (×3,000).

Figure 3

Morphology of dentinal tubules treated with NovaMin, seen under scanning electron microscope (×3,000).

Figure 4

(A, B) Longitudinal sections of a specimen treated with Gluma desensitizer at ×20,000 and ×10,000 respectively. The arrows show characteristic transverse septa while the circled area shows an occluded area.

Figure 5

(A, B) Longitudinal sections of a specimen treated with NovaMin at ×5,000. The arrows show large hydroxycarbonate apatite particles, while circled area shows an occluded area.

Figure 6

Ratio of completely occluded tubules to total tubules. The bar graph depicts the mean ratio of the number of completely occluded tubules to the total number of tubules. The mean value is highest for the NovaMin group, which indicates more completely occluded tubules than the other groups.

Figure 7

Ratio of partially occluded tubules to total tubules. The bar graph depicts the mean ratio of the number of partially occluded tubules to the total number of tubules. The mean value is highest for the Gluma desensitizer group, which indicates more partially occluded tubules than the other groups.