Resonance frequency and removal torque analysis of implants with turned and anodized surface oxides

Abstract

The present experimental study was designed to address two issues. The first was to investigate whether oxide properties of titanium implants influenced bone tissue responses after an in vivo implantation time of six weeks. If such a result was found, the second aim was to investigate which oxide properties are involved in such bone tissue responses. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of 200 nm to 1000 nm. The surface morphology was prepared in two substantially different ways, i.e. barrier and porous oxide film structures. The micropore structure revealed pore sizes of 8 microm in diameter, with a range in opening area from 1.27 microm 2 to 2.1 microm 2. Porosity ranged from 12.7% to 24.4%. The crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. The chemical compositions consisted mainly of TiO2. Surface roughness ranged from 0.96 microm to 1.03 microm (Sa). Each group of test samples showed its own, defined status with respect to these various parameters. The oxide properties of turned commercially pure titanium implants were used in the control group, which was characterized by an oxide thickness of 17.4 +/- 6.2 nm, amorphous type in crystallinity, TiO2 in chemical composition, and a surface roughness of 0.83 microm (Sa). Bone tissue responses were evaluated by resonance frequency measurements and removal torque tests that were undertaken six weeks after implant insertion in rabbit tibia. Implants that had an oxide thickness of approximately 600, 800 and 1000 nm demonstrated significantly stronger bone responses in the evaluation of removal torque values than did implants that had an oxide thickness of approximately 17 and 200 nm (P < 0.05). However, there were no difference between implants with oxide thicknesses of 17 and 200 nm (P = 0.99). It was concluded that oxide properties of titanium implants, which include oxide thickness, micropore configurations and crystal structures, greatly influence the bone tissue response in the evaluation of removal torque values. However, it is not fully understood whether these oxide properties influence the bone tissue response separately or synergistically.

Characterisation of Titanium Dental Implants. II: Local Biomechanical Model~!2009-09-02~!2009-11-20~!2010-04-28~!

“…Since this parameter is not commonly used an analysis of the hybrid parameter S dr was made instead. However, few removal torque studies were found which used the S dr parameter [11,[65][66][67][68] and no uniform correlation seemed to exist.…”

“…This together with the fact that a correlation between S a and removal torque can be found for certain surfaces, indicates that all topographical factors affecting the retention strength are not included in the Local calculation model. Other factors such as chemical composition [66,67,69,70] and electrical properties [71] have been discussed in terms of influencing the retention strength. The calculated results showed a similar trend to interface shear strength results reported in vivo [7,11,65,66] The local model described in the present paper has some inherent limitations, for example in the derivation of the formulae for interfacial shear strength it was assumed that the bone-to-implant contact was 100%.…”

Titanium dental implant surfaces

“…Studies have shown that Ti implants with adequate roughness may enhance bone-to-implant contact [6] and increase the removal torque force [7][8][9]. Elias et al [10] analyzed different methods for increasing surface roughness and improving dental implant osseointegration.…”

Bone Response to Anodized Titanium Implants in Rabbits

“…That is, implants having an oxide layer with a thickness of 600 nm or above are reported to remarkably increase removal torque and histologically show significant advance of bone-implant contact ratio. Currently, many research projects are being conducted to advance implant performance by improving this oxide layer [8][9][10][11][12][13][14] . The purpose of the study is to evaluate the response of osseous tissue to the anodized implants by histologically observing and biomechanically analyzing the degree of osseointegration, and the biologic response between im plant surface and bone tissue over time after implant placement.…”