The use of a bone block with CAD-CAM system for alveolar ridge augmentation is a valuable alternative to autograft because it reduces time, cost, and complications for the patients. Data from a computerized tomographic scan can be used to shape a precise 3-dimensional homologous bone block using a CAD-CAM system.

Randomised controlled trial PURPOSE. To compare the clinical outcome of single implants placed immediately after tooth extraction with those placed 6 weeks after tooth extraction (early placement), and those placed 4 months after extraction and socket healing (delayed placement). MATERIALS AND METHODS.Two hundred and ten patients requiring one single implant-supported crown to replace a tooth to be extracted were randomised into 3 groups of 70 patients each to receive immediate, early (at 6 weeks), or delayed (after 4 months of healing) post-extraction implants, according to a parallel-group design. When needed, patients from the immediate and early groups had bone substitute grafts in the extraction socket, covered with a resorbable membrane, at implant placement. Sockets randomised to delayed implants were grafted in the same manner if poorly preserved, or in the "aesthetic" areas (from second upper premolar to second upper premolar). 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; aesthetics, as assessed using the pink aesthetic score (PES); and patient satisfaction, recorded by blinded assessors. Patients were followed-up for 3 years post-loading. RESULTS.Three years after loading, drop-outs were: five (7.1%) patients from the immediate, nine (12.9%) from the early, and eight (11.4%) from the delayed group. Five implants (9.2%) failed in the immediate, four (6.6%) in the early, and one (1.6%) in the delayed group (P [Freeman-Halton] = 0.282). Apart from the crowns that failed due to implant losses, no other definitive crown had to be remade. Complications affected eleven patients from the immediate group, 12 from the early, and eight from the delayed group (P [chi-square test] = 0.596). Mean peri-implant marginal bone loss after 3 years was -0.33 ± 0.22 mm at immediate, -0.43 ± 0.26 mm at early, and -0.49 ± 0.30 at delayed implants; (P [Kruskal Wallis test] <0.001); there were significant pairwise differences between immediate and early (0.10 mm; CI 95% -0.02; 0.22; P [Dunn-Bonferroni post-hoc] = 0.0391) and immediate and delayed implants (0.16 mm; CI 95% 0.04; 0.27; P [Dunn-Bonferroni post-hoc] = 0.0004), but no difference between early and delayed implants (0.06 ± 0.05 mm; CI 95% -0.06; 0.18; P [Dunn-Bonferroni post-hoc] = 0.6015). Three years after loading, the mean overall PES were 12.25, 11.98 and 11.17 in the immediate, early and delayed groups, respectively (P [Kruskal Wallis test] <0.001); there were significant pairwise differences between immediate and delayed (1.08 ± 0.27 mm; CI 95% 0.45; 1.72; P [Dunn-Bonferroni post-hoc] = 0.0006), and early and delayed implants (0.81 ± 0.27 mm; CI 95% 0.17; 1.46; P [Dunn-Bonferroni post-hoc] = 0.0099), but no difference between immediate and ea...

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Randomised controlled trial PURPOSE. To evaluate whether short (5 to 8.5 mm) dental implants could be a suitable alternative to longer (at least 11.5 mm long) implants for supporting dental prostheses placed in atrophic fully edentulous maxillae augmented with autogenous bone. MATERIALS AND METHODS.Twenty-eight patients with fully edentulous atrophic maxillae having 5 to 9 mm of residual crestal bone height at least 5 mm thick, as measured on CT scans, were randomised into two groups, either to receive four to eight short (5 to 8.5 mm) implants (15 patients) or autogenous bone from the iliac crest to allow the placement of at least 11.5 mm-long implants (13 patients). Both bone blocks and windows at lifted maxillary sinuses were covered with rigid resorbable barriers. Grafts were left to heal for 4 months before placing implants, which were submerged. After 4 months, provisional reinforced acrylic prostheses or bar-retained overdentures were delivered. Provisional prostheses were replaced after 4 months by definitive screw-retained metal-resin cross-arch restorations. Outcome measures were: augmentation, prosthesis or implant failures, any complications, peri-implant marginal bone level changes, and patient satisfaction. Patients were followed-up until 5 years after loading. RESULTS.All patients could be rehabilitated with implant-supported prostheses, but four patients dropped-out from the augmentation group and three from the short implant group. One bilateral sinus lift procedure failed due to infection, though short implants could be placed. Four implants failed in four patients from the augmentation group versus three short implants in three patients (Fisher's exact test P = 0.6500; difference in proportions = -0.17; 95% CI -0.51 to 0.21). No prosthesis failed. Significantly more complications occurred in augmented patients: 12 complications occurred in nine augmented patients versus one complication in the short implant group (Fisher's exact test P = 0.0003; difference in proportions = -0.82; 95% CI -0.97 to -0.41). Periapical radiographs of only four patients were readable, so no bone level could be measured at 5 years after loading. With the exception of three patients from the augmentation group, who were only partially satisfied with function, all remaining patients were fully satisfied with the treatment (P = 0.0957); all would have the treatment again.CONCLUSIONS. This study showed that in patients with fully edentulous atrophic maxillae, short implants can be a preferable alternative to longer implants placed in bone augmented with autogenous bone, the treatment being less invasive, cheaper, faster and associated with fewer complications. CONFLICT OF INTEREST STATEMENT.MegaGen partially supported this trial and donated the implants and prosthetic components used in the present investigation. However, data property belonged to the authors and MegaGen by no means interfered with the conduct of the trial or the publication of its results.