Abstract
Aim:
To evaluate the outcome of immediately loaded mandibular cross-arch
prostheses according to the 'all-on-4' concept supported by implants
placed in fresh extraction sockets up to 18 months after loading.
Materials and methods: In total, 47 patients with a mean age of 62.3
years (range 52 to 78) were rehabilitated with an immediately loaded
fixed cross-arch prosthesis supported by four post-extractive implants. A
total of 188 implants were inserted. Patients received a provisional
fixed dental prosthesis with a metal framework within 48 hours after
surgery and a permanent one 6 months later. The patients were evaluated
clinically and radiographically at implant placement and at 6-, 12- and
18-month follow-up examinations. Results: At the 18-month follow-up, no
implant failed and all restorations were stable. Peri-implant bone
levels amounted to 0.31 ± 0.12 mm after 6 months, 0.58 ± 0.112 mm after
12 months and 0.7 ± 0.107 mm after 18 months. No significant differences
in bone loss were found between axially placed and tilted implants at
the 6-month (0.06 mm; P = 0.115), the 12-month (0.12 mm; P = 0.062) and
the 18-month follow-up (0.08 mm; P = 0.146). Three patients had a
fracture of the provisional restoration, but all of the definitive
prostheses remained stable throughout the study period without any
complications. Conclusions: Within the limits of this study, it can be
suggested that immediately loaded mandibular cross-arch fixed dental
prostheses can be supported by four post-extractive implants, however
larger and longer follow-ups are needed.
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