Endodontology
Online only article
Evaluation of the radiopacity and cytotoxicity of Portland cements containing bismuth oxide

https://doi.org/10.1016/j.tripleo.2007.08.001Get rights and content

Objective

This study aimed at evaluating the radiopacity and cytotoxicity of Portland cements containing bismuth oxide (PcBo) in varying ratios.

Study design

Specimens measuring 10 mm in diameter and 1 mm in thickness were radiographed with an aluminum step wedge using an occlusal film. The radiographs were digitized, and the radiopacity of each material was compared to the different thicknesses of the aluminum step wedge. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of each material was determined in immortalized human periodontal ligament (IPDL) cells.

Results

The results demonstrated that Portland cement with 20% bismuth oxide presented greater radiopacity (P < .05) compared to the mixtures with less bismuth oxide. The cell viabilities of all PcBo groups were statistically similar (P > .05) throughout the experimental period.

Conclusion

These results indicate that Portland cement with 20% bismuth oxide has a greater potential for being used as a root-end filling material compared to Portland cement with less bismuth oxide.

Section snippets

Material preparation

Portland cement and bismuth oxide were mixed in the ratios of 4:1 (PcBo4), 6:1 (PcBo6), and 8:1 (PcBo8). Subsequently, PPc (1.0 g) and Portland cement containing bismuth oxide (PcBo, 1.0 g) were mixed with sterile distilled water (0.4 mL) on a glass slab. MTA was mixed according to the manufacturer’s recommendations. Five specimens (n = 10) measuring 10 mm in diameter and 1 mm in thickness were fabricated from each material tested. The material was packed into aluminum molds and stored for 3

Radiographic evaluation

The results demonstrated that MTA and PcBo4 presented the greatest radiopacity (P < .05) and were equivalent to 6.92 and 6.81 mm of aluminum, respectively. PcBo6 and PcBo8 presented radiopacity values that were equivalent to 3.70 and 3.17 mm of aluminum, respectively. PPc exhibited the lowest radiopacity (P < .05) and was equivalent to 0.86 mm of aluminum (Fig. 2).

Cytotoxicity test

As demonstrated in Fig. 3, the MTA and PPc groups showed statistically higher cell viabilities in 12 and 24 hours compared to other

Discussion

An ideal root-end filling material should exhibit sufficient radiopacity to allow for distinction from adjacent anatomical structures, to evaluate voids and improper contours, and to assess secondary dissolution of the material.11, 12, 13 While some materials possess an inherent radiopacity to a certain degree, others require radiopacifiers such as bismuth oxide and barium sulfate to optimize their radiopaque properties.13

The base material for MTA is Portland cement and bismuth oxide is added

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This paper was supported by Wonkwang University in 2007.

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