الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 194 |  |  |
| | | from | 194 | | |
Abstract
-In this study biocompitability of three different root canal sealers from three
categories was evaluated through two tests
1. Cytotoxicity test (MTT assay) using dental pulp stem cell culture and
2. Subcautanous implantation in rat model followed with histological
examination and immunohistochemical analysis.
Cytotoxicity test
-Dental pulp stem cells were isolated from pulp tissues of non carious ten
premolars extracted for orthodontic purposes then digested by
collagenase enzyme .
-Pulp stem cells were immersed in a culture medium and transferred to a
culture flask and incubated in CO2 incubator.
-The cells were monitored by light microscope with changing the medium
each 24 h .
-When the cells became confluent ,they were passaged
-Sixty three elutes,twenty one from each sealer were prepared
-Sixty three cell culture samples were treated with sealer elutes in a 96
well plates and incubated in CO2 incubator for 1,4 and 7 days. Twenty
one cell culture samples without any elute treatment were used as a
control.
-MTT was added and absorbtion was measured using Eliza spectrometer .
Results of cell culture
During the 2nd passage (P2), the cells showed a single morphological
and phenotypic characteristic, most of the cells had fibroblast
morphology, and evidence of colonies was noticed .The cells maintained
this morphology till the end of P2. The cells showed a fast rate of growth,
reaching 60% confluence on the 2nd day of P2.
Summary
150
Statistical results of cytotoxicity test (MTT assay)
-At day one,there was no significant difference between the four groups.
-At 4 days and 7 days, there was a significant difference in mean
percentage of cell proliferation between groups
-At 4 days and 7 days, the highest mean percentage of cell proliferation
was noted with control group, followed by GuttaFlow Bioseal group, then
Well Root St group , and the lowest mean percentage was noted with AH
plus group .
-For control group, there was no significant difference in mean
percentage of cell proliferation between observation times.
-For all sealers groups, there was a significant difference in mean
percentage of cell proliferation between observation times
-For all sealers groups, the highest mean percentage of cell proliferation
was noted with one day, followed by 4 days, and the lowest mean
percentage was noted with 7 days.
Implantation test
-Eighty four healthy Wistar-Albino male rats were used in the study. The
animals were randomly divided into four experimental groups according
to the type of sealer (each group contains 21 animal).
-Each animal was sedated with an intramuscular injection of midazolam
0.25mg/kg.the rats were anesthetized via intraperitoneal ketamine HCL
(50 mg/kg) and xylazine (7 mg/kg) injection .
-Eighty four polyethylene tubes, sixty three filled with sealers and twenty
one empty were implanted in subcautanous tissues of rats
- Samples were taken after 7, 15, 30 days. At the end of each period (7,
15, and 30 days), 28 animals were sacrificed, 7 from each group. The
animals were sacrificed via cervical dislocation (after anesthesia), as
proposed by the Ethics Committee.
Summary
151
-The samples were prepared for histological examination and
immunohistochemical .
-The blocks were stained with hematoxylin and eosin to view the general
tissue structure
-Also the blocks were stained with CD3 and CD68 markers to study
lymphocytes and macrophages infiltration.
Results of H&E staining
-All groups exhibited an inflammatory response with formation of a
fibrous capsule at 7 days, the inflammatory response and the thickness
of fibrous capsule decreased at 30 days.
Statistical analysis of immunohistohemical staining.
Lymphocytes infiltration
-At 7 day and 15 days, there was a significant difference in mean
percentage of lymphocytes infiltration between groups.
-At 30 days, there was no significant difference in mean percentage of
lymphocytes infiltration between groups
-At 7 day and 15 days, the highest mean percentage of lymphocytes
infiltration was noted with AH Plus group, followed by Well Root St
group, then GuttaFlow Bioseal group, and the lowest mean percentage
was noted with control group.
-For all groups, there was a significant difference in mean percentage of
lymphocytes infiltration between observation times
-For all groups, the highest mean percentage of lymphocytes infiltration
was noted with 7 day, followed by 15 days, and the lowest mean
percentage was noted with 30 days.
Macrophages infiltration
-At 7 day, 15 days, and 30 days, there was a significant difference in
mean percentage of macrophages infiltration between groups.
Summary
152
-At 7 day, 15 days, and 30 days, the highest mean percentage of
macrophages infiltration was noted with AH plus group, followed by
Well Root St group, then GuttaFlow Bioseal group, and the lowest mean
percentage was noted with control group.
-For all groups, there was a significant difference in mean percentage of
macrophages infiltration between observation times
-For all groups, the highest mean percentage of macrophages infiltration
was noted with 7 day, followed by 15 days, and the lowest mean
percentage was noted with 30 days.
Conculsion
-AH Plus which is an epoxy resin based sealer was the most toxic in both
in vitro and in vivo studies
-GuttaFlow Bioseal which is a silicone based sealer was the least toxic in
both in vitro and in vivo studies
-Well Root St which is a calcium silicate based sealer was inbetween
epoxy based sealers and silicone based sealers in its toxicity
Recommendation
-Further studies with larger sample size to evaluate the biocompitability
of different root canal sealers
- Further in vitro and in vivo studies with different species of cell cultures
or animals to evaluate the toxicity of root canal sealers .
-Sealers must not exceed beyond the apex to avoid their possible toxic
effects on periapical tissues