Effect of transition metal dopants on mechanical properties and biocompatibility of zirconia ceramics.

In this study, the effect of transition metal dopants, originally added as colouring agents, on the mechanical properties and biocompatibility of sintered zirconia was investigated. This study confirmed that transition metal dopants could have a slight detrimental effect on the mechanical properties of zirconia. The addition of metal dopants did not affect the adhesion and proliferation of gingival fibroblasts.

Biocompatibility of mineral trioxide aggregate mixed with hydration accelerators.

INTRODUCTION: The aim of this study was to evaluate the biocompatibility of mineral trioxide aggregate mixed with selective hydration accelerators such as calcium chloride (CaCl2), citric acid (CA), and calcium lactate gluconate solution (CLG). METHODS: Inductively coupled plasma-atomic emission spectrometry analysis was used to measure calcium ions in the extracts of test materials. The 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay was performed using MG-63 cells to examine the cytotoxicity of the test materials. The surface of each sample and the growth pattern of the attached cells were observed using scanning electron microscopy (SEM). RESULTS: MTA mixed with 10 wt% CaCl2 and MTA mixed with 43.4 wt% CLG released a higher amount of calcium ions than the other groups. The 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay revealed that the cell viability of MTA mixed with 0.1 wt% CA was significantly higher than pure MTA on 7-day extract (P < .05). MTA mixed with 43.4 wt% CLG showed significantly higher cell viability than the other groups on 1-day extract (P < .05). MTA mixed with 10 wt% CaCl2 in all groups showed the lowest cell viability at all time points (P < .05). Under SEM, elongated and confluent cells were observed in all samples except in samples of MTA mixed with 10 wt% CaCl2. CONCLUSIONS: MTA mixed with 0.1 wt% CA showed good biocompatibility. MTA mixed with 43.4 wt% CLG showed favorable biocompatibility on 1 day. MTA mixed with 10 wt% CaCl2 in all groups showed the lowest cell viability at every time point and poor cell attachment under SEM.

Cytotoxicity of newly developed ortho MTA root-end filling materials.

INTRODUCTION: Various materials have been advocated for use as root-end filling materials. The purpose of the present in vitro study was to compare the cytotoxicity of 4 root-end filling materials: glass ionomer cement (GIC; Fuji II, GC Corp, Tokyo, Japan), reinforced zinc oxide-eugenol cement (IRM; Dentsply Tulsa Dental, Tulsa, OK), and 2 types of mineral trioxide aggregate. METHODS: This study used MG-63 cells derived from a human osteosarcoma. To quantitatively evaluate the cytotoxicity of test materials, the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was used. The cells were exposed to the extracts and incubated. Cell viability was recorded by measuring the optical density of each test well in reference to controls. Each specimen was examined by scanning electron microscopy for the observation of cell morphology. RESULTS: The XTT assay showed that the cell viability of ProRoot MTA (Dentsply Tulsa Dental) was higher than that of GIC and Ortho MTA (BioMTA, Seoul, Republic of Korea) at all time points. IRM showed significantly lower cell viability than the other groups. The scanning electron microscopic analysis revealed that elongated, dense, and almost confluent cells were observed in the cultures of GIC, Ortho MTA, and ProRoot MTA specimens. In contrast, cells on the surface of IRM were rounded in shape, and the numbers and the density of the cells were smaller than that in the other groups. CONCLUSIONS: ProRoot MTA and GIC showed good biocompatibility in this study. However, Ortho MTA showed lower biocompatibility compared with ProRoot MTA and GIC.