Synthesis and properties of hydroxyapatite based composites for dental ceramic applications

การสังเคราะห์และสมบัติของวัสดุผสมที่มีไฮดรอกซีอะพาไทต์เป็นฐานสำหรับประยุกต์เป็นเซรามิกทันตกรรม

Name: Suchittra Inthong

Classification :.DDC: 610.28

LCSH: Ceramics in medicine

LCSH: Biomedical materials

LCSH: Hydroxyapatite

Abstract: This research was conducted in order to synthesize and characterize of the hydroxyapatite (HA) based composite system for the aim of improvement and modification the HA based composite properties for suitable using apply in dental ceramics and medical materials. The synthesis of the HA based composite was used conventional synthesis technique. The resulted of synthesis and optimum conditions of the HA based composite were reported. The study of the HA based composite can be a divide in three part. For the first part of this research, the properties of Sr-doped yttrium stabilized zirconia/ hydroxyapatite (YSZ/HA) ceramics in various sintering temperature were studied. The ratio of YSZ/HA is 80:20 wt. which was doped with strontium carbonate (SrCO3) by 0, 1, 2 and 5 wt.. The preparation of mix powders was used ball milled technique. Then, the powders were compressed moulding and sintered at a temperature from 1100 to 1400 C for 4 h. The XRD resulted showed the mix phase in Sr-doped YSZ/HA composites which consist of YSZ, HA and Sr phase, respectively. The sample which sintered at higher temperature produces a higher intensity of XRD peak. The higher intensity of XRD peak is like to higher crystallinity of composites. The bulk density of composites increased with raising sintering temperature. However, bulk density decreased with increasing Sr content in composites at the same sintering temperature. The maximum bulk density is 4.72 ± 0.05 g/cm3 for Sr-doped 2 wt. and sintered at 1400 C. The average grain size was increased depending on the content of Sr-doped and sintering temperature. The average grain size is around 85.62±14.1-649.17±12.6 nm. The maximum hardness is 4.95 GPa for Sr-doped 2 wt. and sintered at 1400 C. For the second part, the composites of HA-BST were synthesized and characterized. The HA and Ba0.7Sr0.3TiO3 (BST) were prepared by co-precipitate and solid state mixed oxide technique. The BST powders were doped in the HA powders by 0, 5, 10, 15, 20, 25 and 30 wt.%. The mixed powders were compressed to the disc-like shape. Then, the obtained disc was sintered at 1350 C for 4 h. The higher levels of BST in HA-BST composites produced more densification, Vickers hardness, Young’s modulus and fracture toughness with the maximum value as 3.42 g/cm3, 5.01 GPa, 161.70 GPa, and 1.48 MPam1/2, respectively at the BST content lower than 20 wt.. However, the average grain size tends to decrease with increasing BST content. The average grain size is around 1.14 – 12.09 m. Further, dielectric behavior was improved for higher amount BST contented samples. Moreover, the biocompatibility was studied by MTT assays method for determining the cytotoxicity with Vero cell. The HA-BST composite samples were immersed in cell growth water for 24 h. All of the studied samples were found cell viability more than 89 . This result indicates that the HA-BST composites have not cytotoxicity. For the final part, the properties of hydroxyapatite-yttrium stabilized zirconia (HA-YSZ) by various sintering temperature were investigated. The ratio of HA/YSZ is 80:20, 60:40, 40:60, and 20:80 wt., respectively. The HA-YSZ composites were sintered at 1400 and 1500 C. The results indicated that the sintering temperature contributed greatly to densification and the compressive strength of the highest at 4.80 g/cm3 and 74.20 MPa for 80 wt.% of YSZ content in YSZ/HA composites and sintering temperature at 1500 C, respectively. Based on we resulted, the densification increased with increasing sintering temperature, where the compressive strength value was linked to densification for the same ratio amount of YSZ. The higher the YSZ contents also significantly produced the ascendant of densification and the compressive strength. The biocompatibility was studied by MTT assays method for determining the cytotoxicity with Vero cell. The HA-YSZ composite samples were immersed in cell growth water for 24 h. All of the studied samples were found cell viability more than 95 . This result indicates that the HA-BST composites have not cytotoxicity. Moreover, the bioactivity was studied by in vitro cell. The obtained result showed that the ability of this composites has bond interfacial with tissue which was growth and adhered of apatite on the surface related to the processing of bone growth. These test can primary confirm that this material can use safely in living body. For this research, it concludes that hydroxyapatite base composite can improve mechanic properties, non-cytotoxicity. Therefore, it will take improve more properties to confirm the safety of use in the body, these materials have high potential to use in medical and dental applications in the future.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Uraiwan lntatha

Role: Chairman

Name: Sukum Eitssayeam

Role: Member

Name: Gobwute Rujijanagul

Role: Member

Name: Kamonpan Pengpat

Role: Member

Name: Tawee Tunkasiri

Role: Member

Created: 2017

Modified: 2019-12-23

Issued: 2019-12-23

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 610.28 S942S

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Materials Science

Grantor: Chiang Mai University

©copyrights Chiang Mai University

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