Different methods for excavation and staining of caries-infected tissue

Method: Extracted human permanent teeth with open manifest caries lesions were used in three series (A, B, C). A: After sectioning, specimens were evaluated by macro-photos taken under a stereo microscope. A total of 7 different dyes were tested regarding their binding properties. B: Four dyes were further used on dentine after caries removal by rotating bur or chemo-mechanical treatment (Carisolv^®). C: Sound and carious dentine was collected, powdered and further analysed with Fourier Transform Infrared Spectrum (FTIR).

Result: A large variation in staining properties between the seven dyes, in accordance with their covalent and electrostatic binding capacity, was found. Furthermore, the covalently bound dyes showed a formation and staining of smear layer after excavation with bur meanwhile the chemo-mechanical technique did not. Analyses with FTIR showed presumptive ester groups unique to caries.

Conclusion: The endpoint of caries removal is dependent on excavation technique and staining substance used.