Mini Dental Implants for Long-Term Fixed and Removable Prosthetics: A Retrospective Analysis of 2514 Implants Placed Over a Five-Year Period

Abstract

Over the past decade, endosseous implants of increasingly smaller diameters have been introduced into the field of dentistry. Small diameter implants (SDIs) are generally 2.75 mm to 3.3 mm in diameter. They are frequently used in cases of limited alveolar anatomy. Mini dental implants (MDIs) are smaller than their SDI counterparts, with diameters ranging from 1.8 mm to 2.4 mm. They are suitable for long-term use—a task for which the device was approved by the Food and Drug Administration. The following study describes the authors’ experience with MDIs under this indication. Over a 5-year period, 2514 MDIs were placed in 531 patients. The mean duration of follow-up was 2.9 years. The implants supported fixed (1278) and removable prostheses (1236), with nearly equal placement in the mandible and maxilla (1256 and 1258, respectively). The overall implant survival was 94.2%. Based on a Cox proportional hazards model, statistically significant predictors of failure include use in removable prostheses (hazard ratio = 4.28), the posterior maxilla (3.37), atrophic bone (3.32), and cigarette smokers (2.28). Implant failures (145) were attributed to mobility with or without suppuration (19% vs 81%, respectively). The mean failure time for these implants was approximately 6.4 months (193 ± 42 days). This temporally correlates with the osseointegration period. A learning curve was established for this procedure, and implant survival improved with placement experience. Based on these results, the authors have devised treatment guidelines for the use of MDIs in long-term fixed and removable prostheses. MDIs are not a panacea; however, proper training enables the general dentist to successfully implement MDIs into clinical practice.