Surface Roughness of Initial Enamel Caries Lesions in Human Teeth After Resin Infiltration

Abstract

Background: Low viscosity resin infiltration of initial caries lesions is a modern microinvasive method to treat initial cries lesions. However, only scarce information is available about the long-term surface alterations of infiltrated lesions.

Methods: Twenty-eight premolar teeth exhibiting non-cavitated initial caries lesions (International Caries Detection and Assessment System (ICDAS code 1&2)) were divided into two groups, one of which was infiltrated with resin, and the other remained untreated. The teeth underwent two thermocycling procedures. The surface roughness was determined quantitatively, and the results were evaluated statistically. In addition, the surfaces of the lesions were investigated by scanning electron microscopy (SEM), and the surface was analyzed visually with respect to surface irregularities.

Results: The results showed a reduction in the surface roughness that was significant after 2500 thermocycles compared to the untreated surface. In the control specimens, no change in the surface roughness was found. The qualitative SEM data also showed a smooth surface after thermocycling, which supported the statistical findings.

Conclusion: After thermocycling, resin-infiltrated enamel surfaces become smoother and had no additional risk for plaque accumulation.

Keywords: Caries treatment; Initial caries; Resin infiltration; Surface roughness; Thermocycling.

Fig. (1)

Depiction of the experimental procedure. Each surface alteration was followed by a roughness determination and SEM documentation

Fig. (2)

Boxplot graphics of the measured Ra values. The difference between the untreated surface and the infiltrated surface after 2500 thermocycles was significant.

Fig. (3)

Boxplot graphics of the measured asfc values. The difference between the untreated surface and the infiltrated surface after 2500 thermocycles was significant.

Fig. (4)

Boxplot graphics of the measured Ra values in the control specimens. No statistically significant difference was determined for the Ra values between the untreated surface of the lesions and the thermocycled surface.

Fig. (5)

Boxplot graphics of the measured asfc values in the control specimens. No statistically significant difference was determined for the asfc values between the untreated surface of the lesions and the thermocycled surface.

Fig. (6)

SEM documentation of the surface of the initial caries lesions. (a) untreated surface of the lesion; (b) after resin infiltration; (c) after the first thermocycle; (d) after the second thermocycle.

Fig. (7)

EDS line-scan through a resin-infiltrated lesion. The lesion is clearly visible as a dark area within the enamel. The Ca line shows a decreasing Ca content within the lesion, whereas the Ca content representing the resin is increasing. The K behind the element symbol indicates the measured x-ray energy of the K electron-orbital.

Fig. (8)

EDS mapping of C within the same area showing an increased C signal within the demineralized areas of the lesion. The K behind the element symbol indicates the measured x-ray energy of the K electron-orbital.