Single post-extractive ultra-wide 7 mm-diameter implants versus implants placed in molar healed sites after socket preservation for molar replacement: 6-month post-loading results from a randomised controlled trial

Purpose: To test the hypothesis that there is no difference in clinical, radiographic and aesthetic outcomes positioning single post-extractive ultra-wide 7 mm-diameter implants or waiting 4 months to place implant, after molar extraction and the socket preservation procedure. Material and methods: Patients requiring one implant-supported single restoration to replace a failed tooth in the molar region of both maxilla and mandible were selected. Patients were randomised according to a parallel group design into two arms: implant installation in fresh extraction sockets augmented with corticocancellous heterologous bone and porcine derma (group A) or delayed implant installation 4 months after tooth extraction and socket preservation using the same materials (group B). Ultra-wide 7 mm-diameter implants were submerged for 4 months. Outcome measures were implant success and survival; complications; horizontal dimensional changes measured on cone beam computed tomography (CBCT) scans at three levels, localised 1, 2 and 3 mm below the most coronal aspect of the bone crest (level A, B and C); peri-implant marginal bone level changes; implant stability quotient (ISQ); and pink esthetic score (PES). Results: Twelve patients were randomised to group A and 12 to group B. No patients dropped out. No implant failed or complications occurred up to 6-months post-loading. Six months after loading there was more horizontal alveolar bone reduction at immediate post-extractive implants, which was statistically significant. At level A was 1.78 mm ± 1.30 in group A, 0.45 mm ± 0.42 in group B, (difference 1.33 mm ± 1.39; 95% CI: 0.38 to 1.95; P = 0.003); at level B was 0.98 mm ± 1.13 in group A, 0.14 mm ± 0.22 in group B, (difference 0.84 mm ± 1.16; 95% CI: 0.24 to 1.07; P = 0.019); at level C was 0.55 mm ± 0.74 in group A, 0.03 mm ± 0.24 in group B, (difference 0.51 mm ± 0.76, 95% CI: 0.01 to 0.87; P = 0.032). One year after implant placement, mean peri-implant marginal bone loss was 0.43 mm ± 0.37 for group A and 0.10 mm ± 0.10 for group B, showing a statistically significant difference between groups (difference 0.33 mm ± 0.30; 95% CI: 18 to 0.52; P = 0.010). Mean ISQ value was 78.8 ± 2.8 for group A and 79.9 ± 3.6 for group B, showing no statistically significant differences between groups (difference 1.1 ± 2.6; 95% CI: 0.04 to 2.96; P = 0.422). Mean PES was similar in both groups (10.7 ± 1.5 [range: 8 to 13] in group A and 11.7 ± 1.2 [range: 10 to 13] in group B; difference 1.0 ± 2.2; 95% CI: -0.23 to 2.23; P = 0.081). Conclusions: Single post-extractive ultra-wide 7 mm-diameter implants, in combination with socket preservation, might be a possible strategy in the replacement of hopeless molars in both jaws, with high implant and prosthetic survival and success rates, and good aesthetic outcomes. Longer follow-ups are needed to properly evaluate this therapeutic option.