With tooth extractions that already have some bone loss, there can be severe subsequent bone loss, as demonstrated in this video. One way to minimize this is with "ridge preservation". This treatment involves grafting the area of the extraction at the same time as the extractions themselves (see grafting section).
After extractions, the ridge may heal with adequate bone for dental implant placement. However, if too much time elapses between the extraction and implant placement, there may not be enough bone to place any size of dental implant in the remaining area.