The immediate implant (Fig.6 I) stops bleeding from the socket. The partial denture (D) and its metal has lost support from the extracted tooth temporarily. The remaining natural tooth (T)/teeth keep the partial in place. As you may image, the partial will be more stable 3-4 months later when a new crown is cemented over the implant. Nowadays we can place a temporary crown over the immediate implant the same day so that there is no much difference before and after extraction in term of denture stability.
Xin Wei, DDS, PhD, MS 1st edition 11/12/2014, last revision 11/15/2014