Tooth bleaching with low temperature plasma lowers surface roughness and Streptococcus mutans adhesion

Abstract

Aim

To evaluate the structural-morphological changes in enamel surface roughness and Streptococcus mutans adhesion after tooth bleaching using plasma in combination with a low concentration of 15% carbamide peroxide (CP).

Methodologys

Sixty pairs of premolars were randomly assigned to the treatment groups (n = 30; buccal surface, Groups 1A/2A) or controls (n = 30; palatal surface, Groups 1B/2B). Group 1A received a low concentration of 15% CP and low-temperature plasma. Premolars in Group 1B were placed in phosphate-buffered saline and served as controls. The buccal surface of Groups 2A was subjected to 15% CP alone, while the palatal surface was subsequently immersed in PBS (Group 2B). After bleaching, all teeth were soaked for 1 h in artificial saliva at 37 °C. Subsequently, teeth were placed in brain-heart infusion with S. mutans at 37 °C for 24 h. The assessment of the structural-morphological changes was carried out using a biofilm assay, scanning electron microscopy, and atomic force microscopy. Statistical analysis of the data was performed with the SPSS (SPSS Inc., Version 18.0, Chicago, IL, USA). The Student's t test was used to determine if a significant difference occurred to the structural-morphological effects with and without plasma.

Results

Significantly less S. mutans adhesion was observed in Group 1A compared with the other groups (p < 0.05). Moreover, the surface roughness was significantly greater in Group 2A compared with the other groups (p < 0.05).

Conclusions

The application of plasma did not result in any structural-morphological and topographic changes in the enamel. The combinational bleaching method using plasma and a low concentration of 15% CP is less destructive, particularly with respect to tooth surface protection.

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