There is insufficient evidence to determine possible advantages or disadvantages of immediate, immediate-delayed or delayed implants, therefore these preliminary conclusions are based on few underpowered trials often judged to be at high risk of bias. There is a suggestion that immediate and immediate-delayed implants may be at higher risks of implant failures and complications than delayed implants on the other hand the aesthetic outcome might be better when placing implants just after teeth extraction. There is not enough reliable evidence supporting or refuting the need for augmentation procedures at immediate implants placed in fresh extraction sockets or whether any of the augmentation techniques is superior to the others.
Two-year prospective clinical comparison of immediate replacement vs. immediate restoration of single tooth in the esthetic zone.
To compare the immediate restoration of single implants in the esthetic zones performed on implants placed immediately after tooth extraction or 8 weeks later (immediate replacement vs. immediate restoration).
                Sixteen patients (10 women and 6 men) with a mean age of 35 years (ranging from 21 to 49 years old) were treated from 2004 to 2005 for single-tooth replacement in the upper arch. The patients were randomly divided into two groups: in the test group patients received implants placed and restored (non-occlusal loading) at the time of tooth extraction; in the control group implants were placed 8 weeks after tooth extraction and immediately restored. All the patients received tapered effect (TE) implants from the Straumann Dental Implant System. The following parameters were evaluated at the moment of provisional restoration (within 48 h after implant placement) and at the 2 years follow-up visit: marginal bone resorption, papilla index, position of the mucosal margin. The implant stability quotient was measured at the moment of implant placement and at the moment of the delivery of the definitive restoration.
                No statistically significant differences were found in any of the studied parameters between the test and the control groups (P>0.05). The implant stability quotient values between the test and control groups were significant (P<0.05) at the moment of implant placement but were no more significant at the loading of the definitive restoration (P>0.05).
                The results of the present study suggest that immediate replacement without functional loading may be considered a valuable therapeutic option for selected cases of single-tooth replacement in the esthetic area when TE implants are used. Implant stability at the moment of implant placement is slightly inferior in the immediate replacement group, but it does not affect the treatment result.