In vitro and in vivo evaluation of locally produced dental porcelain
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Date
2007
Authors
All Abu Sharbeh, Hazem Yousef
Journal Title
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Abstract
Biocompatibility of dental porcelain is of crucial importance to the long-term
success of dental prostheses because of· its close contact with oral tissues for
extended periods. This study was designed to evaluate the biocompatibility of
locally produced dental porcelain "test" using in vitro and in vivo methods. The in
vitro cytotoxic potential of the test material was evaluated using test on extracts
and direct contact test formats as per ISO 10993-5. Cell culture medium was used
both as a control and an extractant. Additionally, a commercially available product
was included to facilitate comparison of results. HOS cell line (ATCC, USA) was
incubated for 72 hours with the extraction solutions of the test and commercial
materials powders at various concentrations (50, 100, 150, 200 and 250 mg/ml).
Similarly, MRC-5 cell line (ATCC, USA) was incubated for 72 hours with the test
and commercial discs (5 mm in diameter and 2 mm thick). Aging process was
carried out by submerging the discs into 3% Bovine Serum Albumin (BSA) solution
for 96 hours followed by reincubation with the MRC-5 cell line. Cellular response
was assessed using MTT [3-( 4,5-Dimethylthiazol-2-yl)-2 ,5-Diphenyltetrazolium
Bromide] assay for measuring the mitochondrial succinate dehydrogenase (SDH)
activity of living cells. Optical densities were measured at 570 nm using ELISA
(Enzyme Linked lmmunosorbent Assay) reader and then converted to a
percentage of the control for each cell culture well. Results were compared using
one-way ANOVA and Tukey Post-Hoc comparisons at a significance level of P
<0.05. For in vivo study, materials discs were implanted subcutaneously into 12
Sprague-Dawley male albino rats, which were sacrificed in groups of 3 at 1, 2, 3
and 4 weeks after implantation. A semi-quantitative histological analysis of the
tissue surrounding implanted discs was done under an image analyzer. In vitro
cytotoxicity test on extracts showed that the test material was significantly different
from the control at concentrations higher than 150 mg/ml. The mean(SD)
percentage of cellular viability was 102.2(12.8) for 50 mg/ml, 98.9(10.3) for 100
mg/ml, 89.4(15.8) for 150 mg/ml, 86.7(14.6) for 200 mg/ml and 82.9(16.5) for 250
mg/ml. However, the commercial product was significantly different from the control
at concentrations higher than 50 mg/ml. The mean(SD) percentage of cellular
viability was 95.6(14.5) for 50 mg/ml, 85.4(12.4) for 100 mg/ml, 81.5(14.8) for 150
mg/ml, 80.7(14.5) for 200 mg/ml and 79.3(10.9) for 250 mg/ml. Direct test showed
that the materials after aging were not significantly different from the control. The
mean(SD) percentage of cellular viability was 89.2(13.4) for the test and 89.4(14.6)
for the commercial. The materials tested were already significantly different from
the control before the conditioning of BSA. The mean(SD) percentage of cellular
viability was 88.5(12.1) for the test and 88.5(8.9) for the commercial. However, in
both tests, the materials caused mild suppression of SOH activity ( <25% of
control), which is considered to be accepted clinically. In vivo subcutaneous
implantation showed that the macrophage was clearly the dominant cell type at the
implant surface at the first week after implantation, followed by a gradual decrease
as the implantation period increased. On the contrary, fibroblasts and fibrocytes
were the dominant cell types in the tissue surrounding test and commercial discs at
the third and fourth week after implantation. These findings, from pathological point
of view, might be an indicator of biocompatibility.
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Keywords
Dental porcelain