Assessment of diametral tensile strength and microhardness of glass ionomer reinforced by different amounts of hydroxyapatite

Abstract EN

Back ground : Glass ionomer materials lack resistance to wear and pressure and are susceptible to moisture during the initial stages of setting and dehydration.

So this study was done to assess diametral tensile strength and micro hardness of glass ionomer reinforced by different amounts of hydroxyapatite .

Materials and methods : In this study a hydroxyapatite material was added to glass monomer cement at different ratios : 10%, 25 %, 20 %, 15 % and 30 % (by weight).

The diametral tensile strength test described by the British standard specification for zinc polycarboxylate cement was used in this study and the micro hardness test was performed using Vickers micro hardness testing machine and the micro hardness values were calculated and statistical comparison was performed on the tested groups.

Results : The group of glass ionomer cement that contains 20 % hydroxyapatite has higher diametral tensile strength and micro hardness values than other groups of this study.

Also the results showed that the group of glass ionomer cement without hydroxyapatite has the lowest values of diametral tensile strength and micro hardness than other groups.

The groups of glass ionomer cement with 10 %, 15 %, 25 % and 30 % hydroxyapatites also showed increasing in diametral tensile strength and micro hardness values in comparison with group of glass ionomer cement without hydroxyapatite.

Conclusion : The addition of hydroxyapatite to conventional glass ionomer cement will increase its diametral tensile strength and micro hardness.