Immediate, immediate-delayed and delayed post-extractive single implants: 1-year loading RCT data

BACKGROUND: Osseointegrated dental implants are traditionally placed in healed ridges. Immediate post-extractive implants and immediate- delayed are those implants placed immediately after tooth extraction and after 2–6 weeks, respectively. The main advantage is to shorten treatment and to presumably decrease the naturally occurring bone resorption after tooth extraction. To the best knowledge of the authors there are no RCTs comparing all the three procedures. AIM/HYPOTHESIS: The aim of this RCT was to compare the clinical outcome of single implants placed immediately after tooth extraction with im- plants placed 6 weeks after tooth extraction (immediate-delayed placement), and with implants placed after 4 months of socket healing (delayed placement). MATERIAL AND METHODS: Two hundred and ten patients requiring a single implant-supported crown to replace a tooth to be extracted were randomised to receive immediate post-extractive implants (70 patients), immediate-delayed implants at 6 weeks (70 patients), and delayed implants after 4-month healing (70 patients) according to a parallel group design. When needed, patients had the socket grafted with a bone substitute and covered with a resorbable membrane. Implants inserted with at least 25 Ncm torque were left to heal unloaded for 4 months, whereas those inserted with less than 25 Ncm were left to heal unloaded for 6 months. Temporary crowns were delivered and were to be replaced by definitive ones after 4 months. Outcome measures were crown and implant failures, complications, peri-implant marginal bone level changes, aesthetic assessed using the Pink Esthetic Score (PES), and patient satisfaction recorded by blinded assessors. Patients were followed up to 1 year post-loading. RESULTS: Four implants (6%) failed in the immediate, four (6.2%) in the immediate-delayed, and one (1.6%) in the delayed group (P (chi-square test) = 0.369). Six immediate, six immediate-delayed and four delayed implants were affected by one complication each (P (chi-square test) = 0.792). Mean peri-implant marginal bone loss after 1 year was −0.25 ± 0.17 mm (CI95% −0.29, −0.20) at immediate, −0.29 ± 0.14 mm (CI95% −0.32, −0.25) at immediate-delayed, and −0.31 ± 0.16 mm (CI95% −0.35, −0.27) at delayed-placed implants (P (Kruskal Wallis test) = 0.015). One year after loading, the mean total aesthetic score was 12.52, 12.49 and 11.78 at the immediate, immediate-delayed and delayed groups, respectively (P (Kruskal Wallis test) < 0.001). All patients were fully satisfied both for function and aesthetics, and would undergo the same procedure again, with four exceptions (partially satisfied with aesthetics) (P = 0.785). CONCLUSIONS AND CLINICAL IMPLICATIONS: No statistically significant differences for failures, complications and patient satisfaction were observed when placing single implants immediately, 6 weeks or four months after tooth extraction, nevertheless failures were more frequent at immediate and immediate-delayed placed implants. Bone level changes were similar between the different procedures, but aesthetics showed better results at immediate and immediate-delayed implants.