Immediate loading in the completely edentulous mandible: technical procedure and clinical results up to 3 years of functional loading

Objectives: This prospective mono-center study describes a clinical technique to provide dental implants with a temporary cross-arch cantilever bridge functionally loaded on the day of fixture insertion and discusses the 3-year follow-up of four to six machined surface Branemark implants installed in the interforamina area. Material and methods: Ninety Branemark implants were installed in 18 edentulous mandibles. Five patients were heavy smokers and one had Down syndrome. The day of surgery, a 10 unit provisional glassfiber-reinforced cantilever bridge was installed. The final 12 unit bridge was in place after an average of 144 days (range 10-332). Bone-to-implant level was assessed radiologically from the day of surgery up to 3 years. Results: Two out of five fixtures were lost within 3 months in the Down syndrome patient but the provisional bridge continued to function on the three remaining implants until the patient was successfully reoperated. Another implant was lost after 11 months due to a non-detected fracture in the metal framework, resulting in overloading of the cantilever part. As no additional losses occurred during the follow-up time (range 57-26 months), the total failure rate is 3/91 (3.3%). Seventeen of the 18 patients are loading their implants more than 3 years and nine have moved beyond the 4-year period. Average bone remodelling as measured on the apical radiographs from 12 patients at 0, 12 and 36 months revealed a statistically significant bone loss from the initial 0.1 mm [standard deviation (SD) 0.2; range 0-0.7] toward 1.8 mm (SD 0.2; range 1.6-2.2) during the first year of function. (Wilcoxon's signed rank test; P < 0.002). After 3 years, no further significant bone loss occurred. Conclusion: This 3-year study shows that machined surface Branemark implants can be immediately loaded with cross-arch cantilever bridges with an average bone-remodelling pattern indicative of a steady state after 1 year of loading.