Effect of Rotary Instrument Mineral Oil Lubricant on Osseointegration: A Randomized, Blinded Study in Rabbits
The mechanisms of early failures in dental implant osseointegration are unclear. A possible cause of low levels of bone formation is lubricant contamination on implants during insertion. To explore the impact of lubricant contamination on dental implants, we used 5 New Zealand rabbits and inserted 2 implants per tibia in each animal for a total of 4 implants per animal (20 implants in total). In general, bicorticalization was achieved. The first implant was placed as suggested by the manufacturer with no lubricant used (control). The second implant was placed using a freshly lubricated contra-angle handpiece, which was used only for the test implants. Implant allocation was randomized, and the examining histologist was blinded to the results. All implants were placed by the same surgeon. The animals were maintained in accordance with animal experimentation guidelines. None of the implants failed to osseointegrate. Moreover, no significant difference was observed between the test and control groups. Based on the results of this study, the use of rotary instrument mineral oil lubricant did not jeopardize the osseointegration of dental implants in New Zealand rabbits.

Estimated quantity of mineral oil applied after two applications lasting 3 seconds each. No significant difference was found. The applied quantity did not decrease between the first spray and any other spray application.

Figure 2. Morphometric analysis of the bone-to-implant contact (BIC) length of a lubricant-contaminated implant in animal 3's left tibia. The left and right thread images showed correspond to merged microphotographs obtained with a 10× objective. The contact (red) and no contact (yellow) lines used to calculate BIC are highlighted (note that the widths of the original lines used to calculate the contact length were much thinner). Toluidine blue staining. Bar = 200 μm. Figure 3. Microscopic image of the cortical region of a control implant in animal 3's right tibia. Toluidine blue staining. ×1.6 objective. Bar = 500 μm.

Figure 4. Box plot of the total bone-to-implant contact (BIC) obtained with control and lubricated surfaces. Plots showing the lower (Q1), median (Q2), and upper (Q3) quartiles. Figure 5. Box plot of the cortical BIC obtained with control and lubricated surfaces. Plots showing the lower (Q1), median (Q2), and upper (Q3) quartiles.
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