Effect of Hafnium Coating on Osseointegration of Titanium Implants: A Split Mouth Animal Study
Vaishnavi Rajaraman, Deepak Nallaswamy, Dhanraj Ganapathy, S. Rajeshkumar, Padma Ariga, Karthik Ganesh
Abstract
The behaviour of hafnium as surface coating in biological environments has not been studied. Little is known about osseointegration of hafnium-coated titanium implants. Thus, further studies of hafnium coating under biological conditions are required in order to determine the suitability of this material, as a surface coating for biomedical application. The aim of the study is to analyse the difference between hafnium-coated titanium and uncoated titanium by evaluating the osseointegration ability of hafnium metal and mechanism of which promotes better bone integration. The study was conducted with a split mouth design on 16 Wistar Albino rats of both sexes, at the age of 6-7 months, weighing <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mn>2526.5</a:mn> <a:mo>±</a:mo> <a:mn>74.4</a:mn> <a:mtext> </a:mtext> <a:mtext>g</a:mtext> </a:math> . Self-tapping titanium osteosynthesis screws ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mn>4</c:mn> <c:mtext> </c:mtext> <c:mtext>mm</c:mtext> <c:mo>×</c:mo> <c:mn>2</c:mn> <c:mtext> </c:mtext> <c:mtext>mm</c:mtext> </c:math> ) (LeForte System Bone Screw®) were implanted in the mandible of rats: Group A (pure titanium screws, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>n</e:mi> <e:mo>=</e:mo> <e:mn>12</e:mn> </e:math> ) and Group B (hafnium-coated screws, <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>n</g:mi> <g:mo>=</g:mo> <g:mn>12</g:mn> </g:math> ). The implanted screws’ stability was checked and noted with a specially customised torque apparatus during insertion and removal of implant. The tissue sections were then processed for hematoxylin and eosin and Masson’s trichrome for bone and connective tissue examination, after 4 and 8 weeks of placement. Hafnium coating appears to have offered similar biocompatibility (aspartate transaminase (AST), alanine aminotransferase (ALT), and creatine kinase (CK) enzyme assay), statistically significant improvement (independent Student’s <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mi>t</i:mi> </i:math> -test, <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M6"> <k:mi>p</k:mi> <k:mo><</k:mo> <k:mn>0.05</k:mn> </k:math> ) in insertion torque ( <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M7"> <m:mn>25.42</m:mn> <m:mo>±</m:mo> <m:mn>3.965</m:mn> </m:math> ) and removal torque ( <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" id="M8"> <o:mn>29.17</o:mn> <o:mo>±</o:mo> <o:mn>2.887</o:mn> </o:math> ) than commercially pure titanium with insertion torque ( <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" id="M9"> <q:mn>22.08</q:mn> <q:mo>±</q:mo> <q:mn>.575</q:mn> </q:math> ) and removal torque ( <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" id="M10"> <s:mn>25.42</s:mn> <s:mo>±</s:mo> <s:mn>2.575</s:mn> </s:math> ). Hafnium coating in the rat mandible showed promising osseointegration with good tissue biocompatibility. Further human trials of hafnium-coated implants are needed to understand the biological behaviour better to enhance clinical performance.