Clearance from the adjacent tooth translates to 0.3mm clearance from the gingival, buccal and lingual aspects of the prepared surface from the adjacent tooth. Using the tip of your explorer, run through the these areas, making sure that there are no resistance from the tip and no clicking sounds.

The reason for this clearance is for you to have an adequate access for proper finishing and polishing of the restoration. This is also to ensure that the margins can be cleaned by the patient. Extending the preparation to buccally or lingually will weaken the restoration and the tooth structure.

There is a proper way of checking the clearance with the use of the explorer:

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