Abstract
This study investigated the impact of a modified implant macrogeometry on peri-implant healing and its effect on bone-related molecules in rats. Eighteen rats received one implant in each tibia: the control group received implants with conventional macrogeometry and the test group received implants with modified macrogeometry. After 30 days, the implants were removed for biomechanical analysis and the bone tissue around them was collected for quantifying gene expression of OPN, Runx2, β-catenin, BMP-2, Dkk1, and RANKL/OPG. Calcein and tetracycline fluorescent markers were used for analyzing newly formed bone at undecalcified sections of the tibial implants. These fluorescent markers showed continuous bone formation at cortical bone width and sparse new bone formed along the medullary implant surface in both groups. However, higher counter-torque values and upregulation of OPN expression were achieved by test implants when compared to controls. The modified macrogeometry of implants optimized peri-implant healing, favoring the modulation of OPN expression in the osseous tissue around the implants.
Dental Implants; Gene Expression; Bone and Bones
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A and C) Scanning electron microscopy (JEOL, JSM-6510mca, Tokyo, Japan) of the implants (80-100x) in control group. B and D) Scanning electron microscopy (JEOL, JSM-6510mca, Tokyo, Japan) of the implants (80-100x) in test groups.BC and D) Scanning electron microscopy (JEOL, JSM-6510mca, Tokyo, Japan) of the implants (80-100x) in control and test groups, respectively.
The modified macrogeometry favorably interfered with the biomechanical performance of titanium implants. *statistical differences between groups (paired Student’s t-test; p < 0.05). Control group (n = 18): implant with conventional macrogeometry; test group (n = 18): implant with modified macrogeometry and healing chambers.
Gene expression results. OPN levels were positively modulated within the profile of bone molecules in the test group when compared to the control group (p < 0.05). The levels of other bone-related markers did not present significant differences between groups (p > 0.05). *statistical differences between groups (Wilcoxon test; p < 0.05). Control group (n = 18): implant with conventional macrogeometry; test group (n = 18): implant with modified macrogeometry and healing chambers.
Representative imagens of undecalcified longitudinal sections of the implants. Figures 4A and 4B are photo montages of several images of one section of group A and group B, respectively. Bone formation markers (green lines of calcein staining and yellow lines of tetracycline staining) were observed around both the cortical and medullary surface of implants. Left figures 4- Aa, Ab, and Ba are amplified images of the cortical bone region delimited by squares, while right figures 4- Ac, Ad, Ae, Bb, and Bc are amplified images of the implant surface related to medullary bone. (4A, 4B), 4X magnification; (4Aa-Ae; 4Ba-Bc), 10X magnification; bars = 100 µm.