Multiple teeth replacement with endosseous one-piece yttrium-stabilized zirconia dental implants

OBJECTIVES The purpose of this study is to clinically and radiographically evaluate survival and success rate of multiple zirconia dental implants positioned in each patient during a follow-up period of at least 12 months up to 48 months. STUDY DESIGN Eight patients were treated for multiple edentulism with 29 zirconia dental implants. All implants received immediate temporary restorations and 6 months after surgery were definitively restored. 6 months to 4 years after implant insertion, a clinical-radiographic evaluation was performed in order to estimate peri-implant tissues health and peri-implant marginal bone loss. RESULTS Survival rate within follow-up period was therefore 100%. The average marginal bone loss (MBL) from baseline to 6 months was +1.375 ± 0.388 mm; from 6 months to 1 year was +0.22 ± 0.598 mm; from 1 year to 2 years was -0.368 ± 0.387 mm; from 2 years to 3 years was -0.0669 ± 0.425 mm; from 3 years to 4 years +0.048 ± 0.262 mm. The mean marginal bone loss at 4 years from the implants insertion was +1.208 mm. CONCLUSIONS According to several studies, when using a radiographic criterion for implant success, marginal bone loss below 0.9-1.6 mm during the first year in function can be considered acceptable. In our work, radiographic measurements of MBL showed values not exceeding 1.6 mm during the first year of loading and also 1 year up to 4 years after surgery further marginal bone loss was minimal and not significant. This peri-implant bone preservation may be associated to the absence of micro-gap between fixture and abutment since zirconia dental implants are one-piece implant. Moreover, zirconia is characterized by high biocompatibility and it accumulates significantly fewer bacteria than titanium.