PPIB and dental caries: Since β-TCMP is less soluble than β-TCP (Li et al. 2009a), it is formed instead of β-TCP in dental calculi and urinary stones, dentineal caries, salivary stones, arthritic cartilage, as well as in some soft-tissue deposits (LeGeros 1991, 2001; O’Neill 2007; Kodaka et al. 1988; Reid and Andersen 1993; Scotchford and Ali 1995; P’ng et al. 2008).