Date	Event	Description
20 February 2013	New citation required and conclusions have changed	Methods updated. One previously included study now excluded. Five new included studies. Changes to the conclusions of the review. New co‐author.
20 February 2013	New search has been performed	Searches updates to 8 June 2012.
31 October 2008	New citation required and conclusions have changed	Change of authorship. We have added a secondary hypothesis, previously described in the subgroup analyses. We have updated the review adding 11 new included studies (Lindeboom 2006 (previously excluded); Assad 2007; Turkyilmaz 2007; Cannizzaro 2008a; Cannizzaro 2008b; Cannizzaro 2008d; Crespi 2008; Donati 2008; Güncü 2008; Schincaglia 2008; Zöllner 2008) and additional data from two previously included studies (Merli 2007; Testori 2007). Conclusions slightly changed.
31 October 2008	New search has been performed	The searches were updated in June 2008.
10 June 2008	Amended	Converted to new review format.
15 February 2007	New citation required and conclusions have changed	Change of authorship. We have updated the review adding seven new included studies (Cannizzaro 2003 (previously excluded); Fischer 2004; Hall 2006; Oh 2006; Romanos 2006; Merli 2007; Testori 2007), and excluding eight new trials. We also included studies with a minimum follow up of 6 months in function. Conclusions slightly changed.
15 February 2007	New search has been performed	The searches were updated in February 2007.
15 March 2004	New search has been performed	The searches were updated in March 2004.
15 March 2004	New citation required and conclusions have changed	Change of authorship. We have updated the review and added three new included studies (Payne 2002; Romeo 2002; Romanos in press). We have added to the methods of the review section the following possible subgroup analyses to be conducted in the future if appropriate data become available: (1) Whether implants were placed in mandibles or maxillae (2) Whether implants were placed in partially or fully edentulous jaws (3) Whether implants were placed in the anterior or posterior jaw (4) Different number of inserted implants (for instance overdentures supported by two versus overdentures supported by four implants) (5) Whether turned (machined) or implants with a roughened surface were used (6) Whether the trial was supported by implant manufacturer(s) or not.