Figure 6. (a) Malachite green–glutaraldehyde (MGA) aggregates detected in the predentin (pd) of rat incisor. Aggregates appearing as branched filaments (arrowheads) are seen in the spaces located between collagen fibrils. D, dentin. Lead citrate. x81,000. (b) Higher magnification of MGA aggregates. Undemineralized section. x140,000. (c) Section floated on an EDTA solution. The staining is unchanged by the demineralization procedure in predentin (pd). In dentin (D), needle-like aggregates are seen along groups of electron-lucent mineralizing collagen fibrils. x110,000.