CRITERIA FOR CARIES REMOVAL AT THE ENAMEL-DENTIN JUNCTION - A CLINICAL AND MICROBIOLOGICAL STUDY

In the UK cavity preparation at the enamel-dentine junction (EDJ) is c onsidered complete when all soft and/or stained tissue is removed. The aim of the present work was to link the clinical criteria of dentine consistency and dentine colour with the microbiological status of the tissue. Cavities were prepared in 564 teeth. Under rubber dam, access to the EDJ was gained and the sample sites selected (n = 847); Their c onsistency was noted as hard or soft and wet or dry when probed. The c olour of the site was noted as stain-free or stained. Dentine was samp led using a round bur. After microbiological processing the total anae robic count and counts of mutans streptococci and lactobacilli were ex pressed as log(10) [CFU per sample]. Soft sites harboured significantl y more bacteria than hard sites (P < 0.001). Soft and wet sites harbou red significantly more bacteria than soft and dry sites (P < 0.001). S tained and hard sites harboured more bacteria than stain-free and hard sites (P < 0.05) but this difference was not considered to be clinica lly relevant. The relatively simple clinical criteria used here correl ated significantly with the microbial findings. All soft dentine must be removed at the EDJ to ensure minimal infection of the underlying ha rd dentine. However, it may not be necessary to continue preparation u ntil the EDJ is also stain-free.