By Dr. Graham Mount & Dr. Rory Hume
The classification is by SITE and SIZE.
To describe a lesion two numbers are used:
-site 1, 2 or 3
-size 1, 2, 3 or 4
So a lesion is described as, say, a 2.3 – which means site 2, size 3.
When we add the tooth number to that, we know exactly what we have – say, a 2.3 on tooth #12.
So what are the three SITES ?
SITE 1 – Pit and fissure
SITE 2 – Approximal surface.
SITE 3 – Cervical area.
What are the four SIZES ?
SIZE 1 – minimal dentinal spread – just beyond what can be remineralized.
SIZE 2 – moderate involvement of dentine.
SIZE 3 – enlarged, with weakened cusps or incisal edges which need protection from occlusal load.
SIZE 4 – extensive loss of tooth structure.
When you put the two numbers together and you describe the lesion – say, a 2.3 means site 2 (approximal) size 3 (enlarged). A 1.2 means site 1 (pit and fissure) size 2 (moderate) When we add the tooth number to that, we know exactly what we have – say, a 2.3 (approximal, enlarged) on tooth #12.
A note on Size 0 – this can be used for lesions that are not to be restored – lesions that are reversible or arrested.
As you will see, this system of classification is primarily related to future restoration. This is not a system related to caries treatment – caries treatment involves the assessment of risk and activity state, then changing the local biochemistry to cure the disease process, with follow-up monitoring of caries activity state. If you want to find out more about the nature of caries and its diagnosis and treatment at the molecular level, then visit http://www.dent.ucla.edu/ce/caries.treatment. Once the disease is cured then restoration of irreversible lesions can be considered – and this system of classification helps in that phase of care. Some lesions (those that are reversible by chemical means, or those that are not active – ‘are ‘arrested’) do not need to be restored.
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