• Thanomsuk Jearanaiphaisarn, D.D.S.
• Chootima Ratisoontorn, D.D.S., M.S., Ph.D.

Objective To compare the cytotoxicity of two Thai white portland cements mixed with bismuth
oxide (PCA and PCB) with white mineral trioxide aggregate (white ProRoot^® MTA) on primary
human osteoblasts and to investigate cell morphology on the materials.

Materials and methods PCA, PCB and white ProRoot^® MTA were mixed with distilled water.
Standard cylinder discs of each tested material were prepared. Primary human osteoblasts were
exposed to material extracts on different extraction time points (days 1, 3, 7 and 14). Cell viability was
assessed by using methyltetrazolium assay. Differences in mean percentage of cell viability were
analyzed by one-way analysis of variance (p < 0.05). Cell morphology was observed by scanning
electron microscope after being seeded on the material discs and incubated for 24 and 72 hours.
Results For the day 1-extracts, PCB extract was more toxic than the others. However, for the day
3-extracts, percentages of cell viability in PCA and PCB extracts at 72 hours were significantly
higher than that in white ProRoot^® MTA extract (p < 0.05). Culture of cells in day 7-PCA extract
showed significantly more cell viability at 72 hours compared to that of white ProRoot MTA extract
(p < 0.001). Cultures of cells in day 14-extracts showed no significant differences in cell viability
among tested materials. Cells were able to attach and spread well on PCA and PCB within 24 and
72 hours.

Conclusion Days 3, 7 and 14-extracts of PCA and PCB were not toxic to primary human osteoblasts.
However, day 1-PCB extract was more toxic than those of white ProRoot^® MTA and PCA.
The primary human osteoblasts could attach to PCA and PCB in a similar fashion to white ProRoot^® MTA.

(CU Dent J. 2009;32:179-90)