Development of apatite coatings on Ti–6Al–7Nb dental implants by biomimetic process and EPD: in vivo studies

Abstract

This paper compares the results of the effects of a biomimetic coating and electrophoretic deposition (EPD) of hydroxyapatite (HA) on the bond strength between the bone, implant and cell compatibility of Ti-6Al-7Nb dental implants. In the biomimetic process, screw shaped implants were chemically etched and NaOH activated to form hydroxycarbonated apatite after they were soaked for six days in a solution that was five times more concentrated than regular simulated body fluid (SBF). Electrophoretic deposition was also used to obtain a uniform coating of HA on other batchs of screws. Elemental, structural and in vivo histological and biomechanical investigations were carried out on the modified surfaces of the screws. The results show that there was a faster reaction of bone towards the coated implants compared to the uncoated one. More mature bones were observed on HA coated implants and increased mechanical strength (torque value) of bone-implant interface. Higher torque was needed to remove elephoretically and biomimetically HA coated screws from its bed compared to that needed for uncoated one (55, 50?16 and 37?45 N cm respectively). Biomimetic and electrophoretic coating with a bioactive HA leads to high integration between bone and implant by increasing the bioactivity of the product and to promoting mechanical properties of the implanted screws and enhanced osseointegration during the healing period. Owing to the higher roughness and porosity of the EPD coated screws (average R a 52921¡100 nm), the bone growth was much higher than that coated biomimetically (average R a 51550¡88 nm). Out of the two methods tried to form bioactive surface, EPD yields high bone adhesion when compared to the biomimetic coating.

Bioceramic Coatings for Medical Implants

“…In vivo studies performed with screw-type Ti6Al7Nb dental implants coated with HA deposited by EDP showed that these coatings lead to high integration between bone and implant by increasing the bioactivity of the implant, enhancing the mechanical properties of the screws and having a good osseointegration during the healing period compared to the uncoated ones [65].…”

Hydroxyapatite coating deposited on grade 4 Titanium by Plasma Electrolytic Oxidation

“…The layer deposition techniques used to produce calcium phosphate include "plasma spray" [5][6][7][8] , laser ablation, "magnetron sputtering" 9,10 , sol-gel [11][12][13][14] , electrophoresis 15,16 , and biomimetic methods [17][18][19] . In the latter technique, the hydroxyapatite is precipitated from a saturated calcium phosphate solution, similar to that of blood.…”

Sol–gel derived nanohydroxyapatite film on friction stir processed Ti–6Al–4V substrate

“…[1][2][3][4][5][6] The orthopedic and dental applications of HAp are limited by its poor mechanical properties. [7][8][9] Therefore, the combination of metallic implant and HAp coatings can be used in order to take advantage of the mechanical properties of substrate and the biocompatibility of HAp. [10][11][12] Among metallic implants, Ti-6Al-4V alloy has a good biocompatibility and high specific strength which has been utilised in orthopedic applications.…”

“…[10][11][12] Among metallic implants, Ti-6Al-4V alloy has a good biocompatibility and high specific strength which has been utilised in orthopedic applications. 8,10,11 As compared with other methods that have been utilised to synthesise HAp coatings on titanium substrate, sol-gel has several advantages of changing the chemistry or processing conditions in order to modify the microstructure of coatings. [13][14][15] Furthermore, surface modification has an important role in HAp coating process on Ti-6Al-4V substrate.…”