Effect of MgF₂ Additive on the Mechanical Properties in Hydroxyapatite / Zirconia Composites

Abstract

In this study, the effect of MgF2 additive on the mechanical properties of hydroxyapatite (HAp)/zirconia composites was investigated. As a fluoride additive, MgF2 was added to HAp/zirconia composites for the suppression of phase decomposition from HAp to tricalcium phosphate (TCP). Due to the dissolution of MgF2 at the phase decomposition temperature of HAp, the phase decomposition of non-stoichiometric HAp was suppressed. When MgF2 (5, 10 vol%) was added to HAp/zirconia composites, the decomposition of HAp was completely suppressed below 1400oC due to the ion substitution F- of for OH- in the HAp crystal structure. The flexural strength and Vickers hardness of composites was revealed more higher values compared with the MgF2-free composites.

Sintering of the Tricalcium Phosphate-Titania-Magnesium Fluoride Composites

“…Mg 2+ promotes the dental caries formation caused by the high calcification process in the bone formation [37,38]. Even though, the lack of Mg 2+ ion results from the inhibition of bone growth, the degradation of bone structure and the decrease of osteoblast adhesion [37,38]. Evis and Pinar Sun [34] demonstrate the β-TCP structure stabilization and the hydroxyapatite formation by the heat treatment above 800°C.…”

“…Magnesium is an abundant and essential cation in the human body, since it has significant effects on human metabolism [38]. Mg 2+ promotes the dental caries formation caused by the high calcification process in the bone formation [37,38]. Even though, the lack of Mg 2+ ion results from the inhibition of bone growth, the degradation of bone structure and the decrease of osteoblast adhesion [37,38].…”

“…Hot pressed magnesium fluoride has been used as a dome material for many devices due to its excellent mechanical strength and thermal stability [39][40][41]. The study conducted by Kim et al aimed to increase the mechanical properties and to inhibit the phase decomposition of HAp by the addition of MgF 2 in the HAp/ZrO 2 composites [37]. As a result, the MgF 2 (5 and 10 vol%) added to the HAp-zirconia composites completely suppresses the decomposition of hydroxyapatite into TCP below 1400°C owing to the ion substitution F − for OH -in the hydroxyapatite (HAp) crystal structure [37].…”

“…The study conducted by Kim et al aimed to increase the mechanical properties and to inhibit the phase decomposition of HAp by the addition of MgF 2 in the HAp/ZrO 2 composites [37]. As a result, the MgF 2 (5 and 10 vol%) added to the HAp-zirconia composites completely suppresses the decomposition of hydroxyapatite into TCP below 1400°C owing to the ion substitution F − for OH -in the hydroxyapatite (HAp) crystal structure [37]. Many studies show that, the addition of MgF 2 to the tetragonal zirconia and HAp mixtures strongly reduces the tendency of HAp decomposition due to partial substitution of F − for OH -ions in the calcium phosphate structure [42,43].…”

“…The fluorine ion (F − ) has been investigated as an essential element for bone and dental formation in the human body [35,36]. Fluoride compound is known as an effective additive for reducing the phase decomposition of hydroxyapatite due to the crystal structure stabilization [37]. Magnesium is an abundant and essential cation in the human body, since it has significant effects on human metabolism [38].…”