Open Journal of Stomatology, 2013, 3, 447-451 OJST
http://dx.doi.org/10.4236/ojst.2013.38074 Published Online November 2013 (http://www.scirp.org/journal/ojst/)
Is there a connection between synthetic bone grafts and
sisters chromatide exchange?
Banu Gürkan Köseoğlu1, Amila Brkić2*, Mehmet Ali Erdem1, Şükrü Öztürk3, Şükrü Palanduz3,
Kivanç Çefle3
1Department of Oral and Maxillofacial Surgery, School of Dentistry, Istanbul University, Istanbul, Turkey
2Department of Oral Surgery, School of Dentistry, Sarajevo University, Sarajevo, Bosnia and Herzegovina
3Division of Medical Genetics, Department of Internal Medicine, School of Medicine, Istanbul University,Istanbul, Turkey
Received 24 September 2013; revised 25 October 2013; accepted 7 November 2013
Copyright © 2013 Banu Gürkan Köseoğlu et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Background: In oral and maxillofacial surgery, syn-
thetic bone grafts are most widely used as bone sub-
stitutes, due to the limited sources of autologous bone.
The aim of this study was to examine the influence of
three different synthetic bone grafts (Cerasorb, For-
toss and Perioglass) on sisters chromatide exchanges
(SCEs) in peripheral lymphocytes. Materials and
Methods: Peripheral blood samples taken from 68
patients (45 females and 23 males), who underwent
oral surgery procedures, such as apical resection, cyst
enucleation or periodontal curretage, were obtained
for SCE a day before and two months after the sur-
geries. A control group included 30 patients, while the
study group was made of the patients who underwent
bone grafting with Cerasorb® (11 patients), Fortoss®
VITAL (10 patients) or Perioglass® (17 patients). Re-
sults: Comparing with the results of the study group
before and after the treatment, it was concluded that
the results were statistically significant (p = 0.001). In
the Perioglass® subgroup, a greater statistical signifi-
cance (p = 0.003) was noted, than that in either the
Cerasorb® (p = 0.620) or Fortoss® (p = 0.210) sub-
groups, in which there was no statistical significance.
Conclusions: Although further investigations may be
necessary, our results suggest that the synthetic bone
grafts might have an influence on SCE in peripheral
lymphocytes.
Keywords: Bone Graft; Sisters Chromatide Exchange;
Genotoxic; Bone Defect
1. INTRODUCTION
Bone grafts present different spectrum of organic and
syntethic materials that are necessary to provide struc-
tural stability and linkage by stimulating osteogenesis,
which leads to biological repair of sceletal defects.
In oral and maxillofacial surgery, the use of bone
grafts is limited to reconstruction of bone defects after
trauma, cyst or tumor removals in implant and periodon-
tal surgery. The gold standard of bone grafts is consid-
ered to be an autologous bone (bone harvested from the
patient’s own body), due to the retaining of cell viability
[1,2]. However, limited autograft quantities and biologic
performances, extra donor site surgery including morbid-
ity, as well as infection risk and other complaints, have
brought some other materials in use such as alloplasts
[1,3-5]. These synthetic materials are biocompatible, re-
sorbable, easily and rapidly replaceable by authentic
bone tissue [1,6,7]. The resorption rate is synchronous
with bone remodelling [1]. Some of these materials are
bioactive glasses and calcium phosphates which can be
effective for reparation of bone defects in orthopedic and
maxillofacial surgery.
Bioactive glasses are composed of SIO2, CaO, Na2O,
P2O5 and bond to bone through the development of a
surface layer of carbonated hydrohylapatit (HA) [3,8,9].
Some other authors suggest that the mechanism of activ-
ity of Bioactive glasses have an effect of cortical con-
centrations of soluble Si, Ca, P and Na iones, inducing
favorable intracellular and extracellular responses, lead-
ing to rapid bone formation [8]. One of representatives of
these materials is PerioGlass® or Bioglass, which has
proven to be an effective graft material owing to the apa-
tit layer on the surface of the particles, which attracts
osteoprogenitor cells and osteoblasts, thus stimulating
bone formation [3,10]. This material is not only a osteo-
conductive scaffold for new bone formation, it also may
act as a biological membrane retarding epithelial down-
growth [11].
*Corresponding author.

B. G. Köseoğlu et al. / Open Journal of Stomatology 3 (2013) 447-451 448
Calcium phosphates are synthetic materials in the form
of isolated alpha or beta-tri calcium phosphate (beta-TCP)
(Cerasorb®) or in combination with Hydroxyl sulphate
matrix (Fortoss® VITAL). The TCP mostly behaves as
osteoconductive material, which allows bone osteopro-
genitor cells to grow on its surface or in its pores, chan-
nels or pipes, and to differentiate into osteoblast, thus
bringing bone deposition [12]. This phenomenon might
also be called “osteostimulation”, which implies upregu-
lation of osteoblast precursors [13]. However, due to the
fact that this differentiation does not take place in an
ectopic site, the phenomenon does not meet the strict
standard of osteoinduction [14].
Synthetic bone grafts were a subject of various studies
in which their biocompatibility and osteoinductive and
osteoconductive qualities were examinated [1,3,8,10,15].
So far, potential genotoxic effects caused by synthetic
bone grafts are almost unknown.
Sisters chromatide exchange (SCE) is one of the me-
thods used for examination of chromosomes and ge-
netic damages, caused by exposure to potential environ-
mental mutagens and carcinogens [16-19]. It represents
the interchange of DNA replication at apparently ho-
mologous chromosomal loci, involving DNA breakage
and reunion [18].
The aim of this study was to compare in vivo geno-
toxic effects of three commercially available synthetic
bone graft materials: beta-tri calcium phosphate (Cera-
sorb®), beta-tricalcium phosphate in a hydroxyl sulphate
matrix (Fortoss® VITAL) and bioactive glass ceramic
(Perioglass®) by analyzing the frequency of sisters
chromatide exchange of peripheral lymphocytes.
2. MATERIAL AND METHODS
The study was approved by the Istanbul University Eth-
ics Committee for Scientific Research in Humans (NO:
2006/507). Written and oral consents were obtained from
all patients.
2.1. Patient Selection
Sixty eight patients (45 females and 23 males), age range
from 24 to 58 years, who were referred to the Istanbul
University, School of dentistry, Department of Oral and
Maxillofacial Surgery, for oral surgery procedures, such
as apical resection, cyst enucleation or periodiodontal
curettage were included into a study. All participans in
the study were medically healthy, were nonsmokers, and
were not taking any drugs for at least 2 months before
surgery. Work histories excluded relation to chemical
mutagens and/or exposure to ionizing radiation. The pa-
tients were randomly separated into a two groups. The
first group was control group and included 30 patients
(16 females and 14 males). The second group, subdi-
vided into three subgroups, included 38 patients who
underwent oral surgery procedures in combination with
one of the three synthetic bone grafts; Beta-tricalcium
phosphate (Cerasorb®), Beta-tricalcium phosphate in a
hydroxyl sulphate matrix (Fortoss® VITAL) or bioac-
tive glass ceramic (Perioglass®). The Cerasorb sub-
group included eleven patients (7 females and 4 males),
the Fortoss® subgroup comprised ten patients (7 fe-
males and 3 males), while 17 patients (15 females and 2
males) were included into the Perioglass® subgroup. The
quantity of the graft materials, used in all of the patients
from the second group was 2 gr.
Following surgical procedures, the patients were under
antibiotic (Amoxicillin 2000 mg/day for 7 days) and anal-
gesic (Naproxen sodium 1100 mg/day, as needed) therapy.
2.2. Sisters Chromatid Exchange (SCE) Analysis
Procedure
Sisters Chromatid Exchange (SCE) analysis was per-
formed in the cytogenetic laboratory of the Istanbul
University, School of Medicine, Department of Internal
Medicine, Division of Medical Genetics.
Heparinized blood samples (3 ml) taken from all of the
patients one day before and two months after the oral
surgery procedures, were cultured and examined for sis-
ters chromatid exchanges. The peripheral lymphocytes
were cultured in medium containing RPMI 1640 (Bio-
chrom KG, Berlin, Germany) supplemented with 1%
phytohaemagglutinin-M (Biological Industries, Kibbutz-
Beit Haemek, Israel), 20% fetal calf serum, 1% peni-
cilin-streptomycin and 1% L-glutamine (PAA Laborato-
ries GmbH, Pasching, Austria). At 24 hours 0.5 μg/ml
5’-bromodeoxyuridine (BrdU, Sigma Chemical Com-
pany, USA) was added to the medium and it was further
incubated in the dark. Later at the 70th hours a Colchi-
cine (0.2 μ/ml) (Colchicine powder, Sigma Chemical Co,
USA) was added. Two hours later the cells were col-
lected and treated 10 minutes with 0.075 mol/L KCl at
37˚C, then fixed with methanol-acetic acid (Merck,
Darmstadt, Germany) and standard harvesting procedure
was performed. Slides were stained by flourescein plus
Giemsa technique (FPG). The slides were examined by a
Leitz-Ortoplan microscope (100×) with respect to SCE
frequency per metaphases. 30 metaphases were analyzed
for each patient before and after treatment.
2.3. Statistical Analyses
Analyses in this study were performed by NCSS 2007
packet program.
Kruskal-Wallis test was used for group comparison,
while Dunn’s multiple comparison test was performed
for subgroups comparison. For repeated-measures Wil-
coxon test was used. The results were evaluated in a con-

B. G. Köseoğlu et al. / Open Journal of Stomatology 3 (2013) 447-451 449
fidence interval of 95% and p < 0.05 was considered
statistically significant.
3. RESULTS
A blood samples from 68 patients (separated into control
and experimental groups), who underwent one of oral
surgery procedures in combination with synthetic bone
grafts or without, were evaluated for sisters chromatid
exchange a day before and two months after the surgery.
Evaluation of results in control and working groups, be-
fore and after the surgeries have showed no statistical
significance (p = 0.501 and p = 0.209). The mean SCE
frequencies before the surgeries, in patients from control
group, Cerasorb®, Fortos® and Perioglass® subgroups
were 7.06 ± 1.54, 7.41 ± 0.62, 6.95 ± 0.87 and 7.47 ±
0.78 respectively, while these values after the surgery
were 7.06 ± 1.54, 7.32 ± 0.72, 7.08 ± 0.71 and 7.78 ±
0.83, respectively.
The results from the Cerasorb® (p = 0.620) and For-
toss® (p = 0.210) subgroups were not statistically sig-
nificant. However, the results from the Perioglass® sub-
group have shown a difference between blood samples
taken before and after the surgeries, which were statistic-
cally significant p = 0.003 (Table 1). The statistical sig-
nificance of p = 0.001 in SCE frequency before and after
the surgeries, between subgroups appears in Table 2.
While the comparision of the Cerasorb® versus Fortoss ®
and Fortoss® versus Perioglass® subgroups did not show
any statistical significance (p = 0.245 and p = 0.669 re-
spectively), the Cerasorb® versus Perioglass® subgroup
showed a meaningful low value of p = 0.018 (Table 3).
4. DISCUSSION
Sisters chromatid exchange (SCE) of peripheral lym-
phocytes presents one of cytogenetic methods for de-
tecting DNA damage [16]. It is well known that different
medications, chemicals, viral infections, malignant dis-
eases, ultraviolet light and smoking are the most com-
mon factors inducing SCE [17-19]. Because of the men-
tioned, in our study the selection of the patients was lim-
ited to those individuals, who’se medical histories ex-
cluded these factors.
Using the sisters chromatid exchange method, muta-
genetic and carcinogenic potentials of different sub-
stances were examinated [16,17,20-25]. Antibiotics and
non-steroidal anti-inflammatory drugs (NSAIDs) were
just some of the most investigated subjects. Various
studies in vitro and vivo deal with different results and
conclusions. Xie et al. [21] suggest that Tetracycline
induce significant increases in SCE even at the lowest
concentrations, while, according to Istifli & Topaktaş [20]
and Jaju et al. [22], Amoxicillin does not behave
genotoxic, with recommendation for safe usage in cases
of bacterial infections. Also the metabolites of Amoxicil-
lin do not have a significant effect on cell proliferation
[20]. Benzathine penicillin G (BPG) might also be con-
sidered as the “safe” antibiotic for a short-term ex posure
[23], although in cases of a long-time exposure, SCE
Table 1. Results in controle and working groups, before and after the surgeries.
Cerasorb®
subgroup
Fortoss®
ubgroup
Perioglass®
subgroup
Control
group KW P
SCE before procedure 7.41 ± 0.62 6.95 ± 0.87 7.47 ± 0.78 7.06 ± 1.54 2.36 0.501
SCE two months later 7.32 ± 0.72 7.08 ± 0.71 7.78 ± 0.83 7.06 ± 1.54 4.63 0.209
Z −0.48 −1.24 −3,01 -
p 0.620 0.210 0,003 -
Table 2. Results show statisticaly significance in SCE frequency before and after the surgeries.
Cerasorb® subgroup Fortoss® subgroup Perioglass® subgroup KW p
SCE Difference −0.09 ± 0.49 0.13 ± 0.32 0.31 ± 0.34 16.5 0.001
SCE % Changes −1.51 ± 6.56 2.02 ± 5.01 3.86 ± 4.2 16.7 0.001
Table 3. Results obtained by Dunn’s multiple comparison test.
Dunn’s multiple comparison test Difference % Changes
Cerasorb®/Fortoss® 0.378 0.245
Cerasorb®/Perioglass® 0.018 0.018
Fortoss®/erioglass® 0.496 0.669

B. G. Köseoğlu et al. / Open Journal of Stomatology 3 (2013) 447-451 450
frequency changes might be expected [24].
Non-steroidal anti-inflammatory drugs (NSAIDs) in-
clude variety of chemicals with analgesic, antipyretic and
anti-inflammatory effects [16]. In one of our previous
studies, we examined genotoxic effects of the etodolac,
nimesulid and naproxen sodium, and concluded that
short term use of selective and non-selective NSAIDs
was not associated with a significant genotoxic effect
that could be detected using the SCE method in pe-
ripheric lymphocytes [16]. However, findings from
Özkul et al. [25], althought statistically insignificant
were opposite to ours in case of naproxen sodium.
The patients included in our study were under antibi-
otic and analgesic therapy after the surgeries. Following
the results of previously mentioned studies, Amoxicillin
2 gr/day (for 7 days) and Naproxen sodium 1100 mg/day
(as needed) were prescribed. Due to the fact that all of
the patients were under the same therapy, with changes
of SCE frequency in working subgroups, the results of
the study suggests that synthetic bone graft materials
might be genotoxic.
The results before and after the treatment have shown
the statistical significance (p = 0.003) in the Perioglass®
subgroup. Also, multiple subgroup comparison tests
were statistically significant p = 0.001, while compari-
son between subgroups have shown that a meaningful
low value was in the Cerasorb® versus Perioglass® sub-
group (p = 0.018). This finding suggests, that the bone
augmentation with synthetic bone grafts might have an
influence on the sisters chromatid exchange frequency.
Although studies of bone grafts are limited to exami-
nations of their biocompatibility, osteoinductive and os-
teoconductive qualities by radiolographic, histologic or
histomorphometric analysis, a review of the English lit-
erature suggests that this could be the first study investi-
gating a genotoxic influence of the synthetic bone grafts
by sisters chromatide exchange method. Due to the fact
that the examined materials in the previous studies have
shown good results as the bone substitutes [26,27], we
wonder whether the resorption rate of the materials play
a role in their genotoxicity. A TCPs show bioresorbabil-
ity during bone regeneration and completely substitute
for a bone tissue after bone stimulation, while hydroxyl
apatite (HA) remains in the body for a long time after
replantation, due to a low grade of bioresorbability [26].
Low grade of resorption is also characteristic of bioac-
tive glasses, where radiographic density and volume are
more expressed in bone sites treated by these materials
[27]. These senses might explain a meaningful low val-
ues (p = 0.018) in the Cerasorb® (TCP) versus Pe-
rioglass® (bioactive glass) and Cerasorb® versus For-
toss® (TCP + HA) (p = 0.245), as compared with the
results with the Fortoss® versus Perioglass® subgroups (p
= 0.669).
Although this is just hypothesis, because we did not
look at the resorption rate of the materials, we are of the
opinion that the bioresorption of the synthetic bone sub-
stitutes did not have any influence on sisters chromatide
exchange frequency, due to the fact that the blood sam-
ples were taken two months after the bone augmentation,
which is not long enough a period for the graft replace-
ment with the authentic bone tissue.
We hope that with these findings, we will open a gate
to some other researchers and studies that will examinate
the genotoxic influence of other bone synthetic substi-
tutes.
5. CONCLUSION
Although further investigations may be necessary, our
results suggests that some alloplasts such as bioactive
glass ceramic might have an influence on SCE in periph-
eral lymphocytes.
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