Mechanical Properties of Bone Surrounding Osseointegrated MDIs and Standard Implants using Nanoindentation

Objectives: To measure the elastic modulus and hardness of the implant and bone near the bone implant interface in Mini Dental Implants and standard implants via the nanoindentation method.
Methods: NEach of nine clinically healthy New Zealand white rabbits received 2 experimental (3M^TMESPE^TMMDIs) and 2 regular (Ankylos^®) implants in the head of tibia/femur. Standard surgical procedure was used for osteotomy according to the manufacturers’ protocols. The animals were euthanized after 6 weeks and specimens were removed en bloc, embedded in a light curing methyl methacrylate resin, sectioned using the Leica SP 1600 saw microtome. The specimens thus obtained were glued to an acrylic plate, ground with CarbiMet^® abrasive papers from 240 to 600 grit, polished with SiC abrasive papers, TexMet^® 1500 cloth and diamond paste. The elastic modulus (E) and hardness (H) of bone surrounding the implants were measured with a nanoindenter on implant surface, bone implant interface and bone beyond 200µm at three zones; coronal, middle and apical.
Results: There were no statistically significant differences in the elastic modulus (p>0.05) between the two groups in all three zones i.e. implant surface, near bone implant interface and bone at 200µm. There were statistically significant differences between the two groups in the hardness of bone at 200µm (p<0.05). However, the differences were not significant in the other two zones i.e. implant surface and bone implant interface (p >0.05). The differences were not significant in the hardness and elastic modulus of bone near the interface and at 200µm in the Ankylos^® and MDIs.
Conclusions: The mechanical properties of 3M™ESPE™ MDIs and a standard dental implant were found to be similar.