The future experiment PANDA@FAIR is a fix-target ppbar machine that will run in the energy range [1.5-15.0] GeV, and it is supposed to reach a peak luminosity of about 2 * 10^31 cm-2 s-1 in the first phase of data taking. This will allow to perform a number of analyses which are suppressed or forbidden at e+e- colliders, especially in the sector of charm- and charmonium physics. To investigate narrow resonances, measure their width and understand their properties is the core of the PANDA physics program in the "day-one" experiment. This contribution reports about the feasibility studies for new supposedly exotic states at the DDbar threshold in PANDA, and the technique to measure the width of very narrow states by performing a threshold scan. The case of the Ds2317 will be discussed and preliminary Monte Carlo simulations will be shown together with new theoretical developments to evaluate cross section and rates for the process ppbar-->DsDs2317, as an original part of the PANDA physics program. Eventually new ccbarssbar resonances could be investigated in the DsDs2317 system. We recall that recently LHCb published on four ccabssbar resonances in the Jpsi-phi invariant mass system through B decays. We also recall that recently charged Z states at DD and DD* thresholds have been observed by BES III, namely the Z(3900) and the Z(4020). However, a Z states at the DD threshold has not been found yet, although theoretically possible. Due to the expected quantum numbers (predicted 0+ in S-wave) it cannot be observed in \pi\pi transitions from an initial 1 -- state. Using antiproton-proton annihilation at PANDA@FAIR a copious production of such a state would be feasible, in particular when 0+ tetraquark is present near the DD threshold.