Interventions for replacing missing teeth: dental implants in fresh extraction sockets (immediate, immediate-delayed and delayed implants).

'Immediate' implants are placed in dental sockets just after tooth extraction. 'Immediate-delayed' implants are those implants inserted after weeks up to about a couple of months to allow for soft tissue healing. 'Delayed' implants are those placed thereafter in partially or completely healed bone. The potential advantages of immediate implants are that treatment time can be shortened and that bone volumes might be partially maintained thus possibly providing good aesthetic results. The potential disadvantages are an increased risk of infection and failures. After implant placement in postextractive sites, gaps can be present between the implant and the bony walls. It is possible to fill these gaps and to augment bone simultaneously to implant placement. There are many techniques to achieve this but it is unclear when augmentation is needed and which could be the best augmentation technique.