Histomorphometric Analysis of Flaplessly Placed and Early Loaded One-Piece Mini Dental Implants in Overdenture Patients

Abstract

Mini dental implants (MDIs) are an affordable alternative for overdentures in medically compromised patients with reduced bone volume. This human study reports the histomorphometric analysis of early loaded and flaplessly placed tapered, one-piece MDIs (ILZ, Southern Implants; Sa: 1.5 μm) after 7 to 11 months in function. Patients agreed to have an additional MDI placed and removed for evaluation. MDI stability was assessed via Periotest prior to implant removal. Histologic sections of four mandibular and three maxillary MDIs with surrounding bone were processed, and the bone-to-implant contact (BIC) was analyzed. At retrieval, the MDIs were in function for more than 6 months, were clinically healthy, and had mean probing pocket depths of 1.4 mm and 1.6 mm in the maxilla and mandible, respectively. Periotest values were < 5.5, indicating clinical stability. Most of the screw threads were filled with bone and revealed an intimate BIC, without any signs of intervening fibrous tissue layer. In both arches, the mean BIC was 68.5%. Large osteocytes could be identified in the calcified tissue, indicative of mature peri-implant bone. It can be concluded that MDIs, when loaded within 2 weeks in either arch, provide proper clinical stability and high BIC after 6 months.