QUANTITATIVE EVALUATION OF EXPERIMENTAL BONE REGENERATION USING INDENTATION TESTS.

Valéria Trombini Vidotto,José Ricardo Lenzi Mariolani,William Dias Belangero,Nilza Alzira Batista

doi:10.1590/1413-785220172502164015

Valéria Trombini Vidotto, José Ricardo Lenzi Mariolani + Show 2 more

Open Access

https://doi.org/10.1590/1413-785220172502164015

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Abstract

ABSTRACTObjectives: To determine whether the macroindentation test can be applied to quantitatively assess bone regeneration. Methods: A 3.2 mm diameter transverse monocortical defect was created on the medial aspect of both proximal metaphyses of the tibia of male Unib-WH rats. For the macroindentation tests, we used 5.00 mm diameter indenters with a 3.2 mm tip. Defect testing was performed 1 to 12 weeks following the surgical procedures to compare the hardness of the newly developed tissue over the 12-week study period. Additional histological, morphological and physical/chemical data were obtained by optical and electronic microscopy, Raman, and energy dispersive x-ray spectrometry (EDS). Results: The mean indentation forces increased in a time-dependent manner from 4 to 12 weeks (p<0.001). Tests performed with the 5.0 mm diameter tip were not able to measure the indentation forces in the first week after the procedure. Moreover, in the second postoperative week indentation forces and the newly formed tissue within the spinal canal were greater than those measured in the fourth and eighth weeks. Conclusions: The macroindentation test can be used to quantitatively assess bone regeneration in experimental studies. The choice of indenter tip diameter should consider the study design. Level of Evidence II, Diagnostic Studies.

Highlights

In 5–10% of fractures, bone healing takes longer than expected and bone consolidation is not achieved.[1]
Indentation force increased in a time-dependent manner for both 3.2-mm and 5.0-mm diameter indenters. (Figures 1 and 2, and Table 2) data from samples taken from the 1-week follow-up could not be obtained with the 5.0-mm diameter indenter
The initial stage of bone formation was observed at the margins of the defect, where multiple ossification centers composed of osteoid and initial trabecular formation could be seen one week after tibial perforation. (Figure 3)

Summary

Introduction

In 5–10% of fractures, bone healing takes longer than expected and bone consolidation is not achieved.[1] This fact highlights the importance of developing novel therapeutic, clinical or surgical strategies to accelerate bone healing and avoid nonunion. Biomechanical tests to quantitatively assess bone repair are important tools to evaluate the efficiency of these strategies. Many biomechanical tests are used in animal models to evaluate implant performance, bone repair, and the quality of the newly formed bone, such as tensile, bending and torsion tests.[2,3,4,5,6,7] The indentation test is used in mechanical engineering to determine the hardness of a material to deformation, and this test can be used to quantify the hardness of newly developed tissue on bone surfaces. Micro and nanoindentation tests are commonly used for this purpose, but

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