Immediate loading of post-extractive versus delayed placement of single implants in the anterior maxilla: a 1-year randomised controlled trial.

BACKGROUND: Immediate post-extractive implants are those implants placed immediately in a fresh extraction socket. The main advantage of this procedure is to shorten the duration of the treatment, however, immediate post-extractive implants might be at a higher risk of complications and failures. Another advantage of immediate post-extractive implants is that they could decrease the naturally occurring bone resorption after tooth extraction, which may improve the final aesthetic outcome. Delayed implant placement after healing of the socket is preferred, in an attempt to minimise the risk of implant failures and complications. Various ridge preservation procedures are effective in decreasing the post-extractive physiological bone resorption. It would be useful to know whether we could have a better clinical outcome by preserving the extraction sites or whether similar results can be obtained by placing implants immediately after tooth extraction, shortening the treatment time. AIM/HYPOTHESIS: To compare the effectiveness of immediate post-extractive single implants with delayed implants placed in pre- served sockets after 4 months of healing. Implants that achieved an insertion torque of at least 35 Ncm were immediately non-occlusally loaded. MATERIAL AND METHODS: Just after tooth extraction, 50 patients requiring a single immediate post-extractive implant in the maxilla from second to second premolar were randomly allocated for either immediate implant placement (immediate group; 25 patients) or for socket preservation using an algae-derived bone substitute, covered by a resorbable collagen barrier (delayed group; 25 patients) in one centre. Bone-to-implant gaps were filled with an algae-derived bone substitute. Four months after socket preservation, delayed implants were placed. Implants (XiVE, Dentsply Friadent, Mannheim, Germany) inserted with an insertion torque of at least 35 Ncm were immediately loaded with non-occluding provisional single crowns, then replaced, after 4 months, by definitive crowns. Patients were followed up to 1 year after loading. Outcome measures were implant failures, complications, aesthetics assessed using the Pink Esthetic Score (PES), peri-implant marginal bone level changes and patient satisfaction, recorded by blinded assessors. Differences in the proportion of patients with implant failures and complications were compared between the groups using the Fisher’s exact probability test. Differences of means at patient level for continuous outcomes between groups, were compared by t-tests. The Mann-Whitney U test was used for calculating patient satisfaction. All statistical comparisons were conducted at the 0.05 level of significance. RESULTS: Nine implants were not immediately loaded in the immediate group versus 19 implants in the delayed placement group, because an insertion torque ≥ 35 Ncm could not be obtained, the difference being statistically significant (difference = 0.40; 95% CI: 0.652 to 0.148; P = 0.010). Two patients dropped out 4 months after loading in the delayed group versus none in the immediate group. Two implants failed in the immediate group versus none in the delayed group, with the difference showing no statistical significance (95% CI: 8.4 to 26.0; P = 0.490). Three minor complications occurred in the immediate group and 2 in the delayed group, and this was not statistically significant (95% CI: 18.2 to 24.0; P = 1.000). At 1 year after loading there were no statistically significant differences in the mean aesthetic score and in the marginal bone loss (P = 0.090; P = 0.06). All patients were fully satisfied, both for function and aesthetics at 4 months as well as at 1 year after loading. CONCLUSIONS AND CLINICAL IMPLICATIONS: No significant differences were observed between the two procedures, although the only two implant failures were for immediate post-extractive implants. It seems more difficult to obtain an implant insertion torque superior to 35 Ncm in sockets preserved with algae-derived bone substitute after a 4-month healing period, than at immediate post-extractive sites.