Class V Question

[denticus]

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When talking about class V carious lesions, what does it mean when they say that the cones of decay have an apex to base relationship at the DEJ?

 

[Streetwolf]

It's a smooth surface carious lesion. Imagine how an x-ray looks, a 2D image. Picture a segment of the buccal surface (though this wouldn't be on an x-ray image). The carious lesion would travel towards the DEJ in the shape of a triangle, except going from the base to the point. When it hits the DEJ it meets less resistance from the tooth and so it can spread laterally, forming the base of the next triangle. This is a "point to base" relationship.

In contrast, occlusal caries (class I for instance) would be "base to base".

Sorta looks like this (class V):

(pulp side) <|<| (enamel side)

The triangle on the right would be the decay going through the enamel from right to left. The triangle on the left would be the decay going through the dentin from right to left. Notice how it starts more spread out and as it penetrates deeper, it converges towards a point. At the DEJ (in between triangles), it spreads laterally.

 

[denticus]

It's a smooth surface carious lesion. Imagine how an x-ray looks, a 2D image. Picture a segment of the buccal surface (though this wouldn't be on an x-ray image). The carious lesion would travel towards the DEJ in the shape of a triangle, except going from the base to the point. When it hits the DEJ it meets less resistance from the tooth and so it can spread laterally, forming the base of the next triangle. This is a "point to base" relationship.

In contrast, occlusal caries (class I for instance) would be "base to base".

Sorta looks like this (class V):

(pulp side) <|<| (enamel side)

The triangle on the right would be the decay going through the enamel from right to left. The triangle on the left would be the decay going through the dentin from right to left. Notice how it starts more spread out and as it penetrates deeper, it converges towards a point. At the DEJ (in between triangles), it spreads laterally.

Thanks streetwolf! This is why I keep coming back to SDN: it's full of terrific people. Good luck all.