Radiographic finding of tooth shows radiolucency reaching the middle 1/3rd of dentin. Based on radiographic finding, this tooth will be categorised as _____ according to latest ICCMS guidelines.: (A) RA2, (B) RA3, (C) RC5, (D) RB4
Answer is D. The ICCMSTM classifies tooth surfaces radiographically as follows: (modified from Agustdottir et al ; Ekstrand et al (22]).
0 = No radiolucency.
RA: Initial stages
1 = radiolucency in the outer ½ of the enamel 
2 = radiolucency in the inner ½ of the enamel ± EDJ (enamel-dentin junction) (this stage is recommended for restorative care in the US, if the radiolucency touches the EDJ)
3 = radiolucency limited to the outer 1/3 of dentin (in some countries, especially the US, this stage is classified as moderate).
RB: Moderate stages
4 = radiolucency reaching the middle 1/3 of dentin.
RC: Extensive stages
5 = radiolucency reaching the inner 1/3 of dentin, clinically cavitated
6 = radiolucency into the pulp, clinically cavitated.
ICCMSTM Caries Risk Likelihood Matrix