G.V. Black's classification sorts carious lesions (and the restorations that fix them) by location. It's used in charting and in nearly every operative procedure you'll assist on, so it's worth knowing cold.
The six classes
- Class I: pits and fissures. Occlusal surfaces of premolars and molars, buccal or lingual pits of molars, lingual pits of upper incisors.
- Class II: proximal surfaces of premolars and molars. The classic MO, DO, or MOD.
- Class III: proximal surfaces of incisors and canines that do not involve the incisal angle.
- Class IV: proximal surfaces of incisors and canines that do involve the incisal angle. A chipped corner that gets rebuilt.
- Class V: the gingival third of the facial or lingual surface of any tooth. Root caries and abfraction lesions live here.
- Class VI: cusp tips of posterior teeth and incisal edges of anterior teeth. Added after Black's original five.
Remembering them
Think front versus back, then where on the tooth. Back teeth: chewing surface is I, between the teeth is II. Front teeth: between the teeth is III, and if the corner's gone it's IV. Near the gumline on any tooth is V. On the very tip is VI.
In a chart note, the class tells the team what kind of prep and matrix to expect. A Class II needs a matrix band and wedge; a Class V on the facial usually doesn't.