A numerical system for recording the gingival health used primarily in children. It was first described by I. Schour and M. Massler in 1947. The ‘P’ represents that part of the gingival tissue occupying the interproximal space between two teeth (papilla); the ‘M’ represents the free gingival tissue collar on the labial, lingual, and buccal aspects of the teeth (marginal gingiva) and the ‘A’ represents the gingiva firmly attached to the underlying bone (attached gingiva). The severity of the inflammation is indicated on a scale of 0–4. When first described, only the labial gingivae of the lower six anterior teeth were examined.