  We here discuss the results of 3d MonteCarlo simulations of a minimal lattice
model for gelling systems. We focus on the dynamics, investigated by means of
the time autocorrelation function of the density fluctuations and the particle
mean square displacement. We start from the case of chemical gelation, i.e.
with permanent bonds, we characterize the critical dynamics as determined by
the formation of the percolating cluster, as actually observed in polymer gels.
By opportunely introducing a finite bond life time $\tau_b$ the dynamics
displays relevant changes and eventually the onset of a glassy regime. This has
been interpreted in terms of a crossover to dynamics more typical of colloidal
systems and a novel connection between classical gelation and recent results on
colloidal systems is suggested. By systematically comparing the results in the
case of permanent bonds to finite bond lifetime, the crossover and the glassy
regime can be understood in terms of effective clusters.
