Caries detector

Definition

Caries detectors contain approx. 1% propylene glycol and pigments. They can visualize demineralized areas (Fusayama, Takatsu & Itoh, 1979)1.  

Mechanism

Propylene glycol can penetrate the pores caused by the caries and thereby transport the dye with it. Healthy dentin has a small pore diameter which cannot be penetrated by the dyes.
The closer to the pulp, the greater the tubule diameter. False positive results can be possible (Kidd et al., 1989)2 (Fusayama and Terashima)3.

The solution stains the zone of decomposed dentin and zone of bacterial invasion, while the zone of demineralization, "dead tracts", zone of sclerotic dentin and unchanged dentin are not stained (Fusayama and Terashima)3 (see Dentin caries). Only irreversibly infected dentin is stained red (Yip et al.,1994).

The solution described above can also be used to diagnose the often difficult-to-detect cracked tooth syndrome by visualising the split infected by bacteria.

References

1. FUSAYAMA, T., TAKATSU, T. & ITOH, K. (1979) New composition of
   caries detector. Japanese Journal of Operative Dentistry, 22, 37.
2. KIDD, E.A., JOYSTON-BECHAL, S., SMITH, M.M., ALLAN, R., HOWE,
   L. & SMITH, S.R. (1989) The use of a caries detector dye in
   cavity preparation. British Dental Journal, 167, 132.

3. Fusayama T, Terashima S: Differentiation of two layers of carious dentin by staining. J Dent Res 1972; 51:866.

4. YIP, H.K., STEVENSON, A.G. & BEELEY, J.A. (1994) The specificity
   of caries detector dyes in cavity preparation. British Dental
   Journal, 176, 417.