An index that evaluates the plaque revealed on the buccal and lingual non-restored surfaces of the teeth on a scale of 0 to 5, defined by G. A. Quigley and J. W. Hein in 1962 and modified by S. Turesky, N. D. Gilmore, and I. Glickman in 1970. All teeth except the third molars are assessed. An index for the entire mouth is determined by dividing the total score by the number of surfaces examined.