“…Polyphosphates and phosphonates are known inhibitors of dental caries and cal culus [Harris et al, 1967;Francis et al, 1973;Anbarel al., 1974a, b] and a number of investigations have been carried out in attempts to determine and quantitate the caries-and calculus-related phenomena which are implicated in these effects (Fran cis et al, 1973(Fran cis et al, , 1977Bisaz et al, 1976;McGaughey and Stowell, 1977;Woeltgens et al, 1979;White and Nancollas, 1980;Gonzalez, 1971], The compounds employ ed in such studies have commonly been pyrophosphate (PP), tripolyphosphate (TPP), trimetaphosphate (TMP), hexamet aphosphate (HMP), ethane-1-hydroxy-1,1-diphosphonate (EHDP), methanediphosphonate (MDP) and its dichloro de rivative. The name 'hexametaphosphate' is a misnomer in two respects: The term 'meta' is properly used to designate a ring compound, whereas HMP is a linear chain, and the chain is not necessarily composed of 6 P groups.…”