Immediate functional loading of TiOblast dental implants in full-arch edentulous maxillae: a 3-year prospective study

Abstract

Introduction: Immediate functional loading of dental implants for full-arch restoration is a patient-friendly approach, shown to be feasible with a good long-term prognosis in a completely edentulous mandible. For the complete restoration of the maxilla, acceptable long-term clinical follow-up is lacking or based on case reports rather than on prospective studies.

Objectives: This prospective mono-centre study reports the 3-year outcome of immediately functionally loaded Astra Tech Dental implants in completely edentulous maxillae based on clinical survival and success based on radiographical assessment of bone level.

Material and methods: One hundred and ninety-five Astra Tech TiOblast surface fixtures were installed in 25 consecutively treated patients (age range: 42-76 years), of whom eight were smokers, 12 had a confirmed history of periodontitis and six had poor bone quality normally deemed for delayed loading. Fixtures and abutments were inserted in a one-stage procedure and functionally loaded within 24 h with a 10-unit provisional glass-fibre or metal-reinforced screw-retained restoration. After 6 months, each implant was checked for stability using a manual torque of 20 N cm and the provisional restoration was replaced by a 10-12-unit screw-retained metal-ceramic or metal-resin cantilever bridge. Bone level was assessed radiographically from the day of surgery up to 3 years and used to calculate mean bone loss at the patient level and individual implant success.

Results: No failures occurred in implants or prostheses, the total survival rate being 100%. Mean marginal bone loss was 0.58 mm (SD 0.58); 0.6 mm (SD 0.53); 0.63 (SD 0.61); and 0.72 (SD 0.63) after 6 and 12 months, and 2 and 3 years, respectively, yielding a 100% success at the patient level. Wilcoxon's signed ranks test showed only statistically significant bone loss between baseline and 6 months and a steady-state condition during all other intervals. At the individual fixture level, 82% lost <1 mm marginal bone between baseline and 1 year. After 3 years, 86% have <1.5 mm total bone loss and can be considered a success. The fixtures expressing more bone loss were all inserted in smokers.

Conclusion: Immediate loading of a full-arch maxillary bridgework on 7-9 Astra Tech TiOblast implants is a predictable treatment option with 100% fixture survival and stable bone-to-implant contact up to 3 years. The steady state in bone remodelling is indicative of a good long-term prognosis in non-smokers but smokers seem to be more prone to bone loss.