Clinical performance of the near-infrared imaging system VistaCam iX Proxi for detection of approximal enamel lesions

Abstract

Objectives/aims: Apart from the visual detection of caries, X-rays can be taken for detection of approximal lesions. The Proxi head of VistaCam iX intraoral camera system uses near-infrared light (NIR) to enable caries detection in approximal surfaces. The aim of this study was to evaluate the performance of the NIR for the detection of approximal enamel lesions by comparison with radiographic findings.

Materials and methods: One hundred ninety-three approximal surfaces from 18 patients were examined visually and using digital radiographs for presence or absence of enamel lesions. Then digital images of each surface were produced using the near-infrared light. Correlation between methods was assessed using Spearman's rank correlation coefficient (r_s). Agreement between radiographic and NIR findings was calculated using the kappa coefficient. McNemar's test was used to analyse differences between the radiographic and NIR findings (α=0.05).

Results: Moderate correlation was found between all detection methods (r_s=0.33-0.50, P<0.0001). Agreement between the radiographic and NIR findings was moderate (κ=0.50, 95% CI=0.37-0.62) for the distinction between sound surfaces and enamel caries. No significant differences were found between the findings (P=0.07).

Conclusion: Radiographs and NIR were found to be comparable for the detection of enamel lesions in permanent teeth.

Figure 1

Examples of images using the VistaCam iX Proxi head. In some NIR images, a halo can be seen in the tooth, which is presumably due to the fact that light gets reflected from the round glass on the inner lens of the camera. The reflection can only be seen on white background. This lens has been replaced in the new commercially available device by a specifically coated lens that does now longer cause this irritation. (a) Image of teeth with the intraoral camera (45 distal, 46 mesial). (b) Corresponding bitewing radiograph (no radiolucency seen in 45 distal/46 mesial). (c) Corresponding NIR image.

Figure 2

Examples of images using the VistaCam iX Proxi head. In some NIR images, a halo can be seen in the tooth, which is presumably due to the fact that light gets reflected from the round glass on the inner lens of the camera. The reflection can only be seen on white background. This lens has been replaced in the new commercially available device by a specifically coated lens that does now longer cause this irritation. (a) Image of teeth with the intraoral camera (24 distal, 25 mesial). (b) Corresponding bitewing radiograph (D1 lesion seen in 25 mesial). (c) Corresponding NIR image. The circle indicates the area that is associated with demineralisation of the enamel.

Figure 3

Examples of images using the VistaCam iX Proxi head. (a) Image of teeth with the intraoral camera (24 distal, 25 mesial). (b) Corresponding bitewing radiograph (D2 lesion seen in 24 distal, D3 lesion seen in 25 mesial, this surface was not included in the study). (c) Corresponding NIR image. The circle indicates the area that is associated with demineralisation of the enamel.

Figure 4

Examples of images using the VistaCam iX Proxi head. (a) Image of teeth with the intraoral camera (14 distal, 15 mesial). (b) Corresponding bitewing radiograph (no radiolucency seen in 14 distal/15 mesial). (c) Corresponding NIR image. The dark area shows that the crystal structure is intact in this area. The slightly more bright impression left to this is caused by the radius in which the surface is bent.