مجال التميز
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تميز دراسي و بحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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The Slice Culture Method for Following
Development of Tooth Germs In Explant Culture
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رابط إلى البحث:
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Click here
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تاريخ النشر:
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July 2013
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موجز عن البحث:
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Explant culture allows
manipulation of developing organs at specific time points, and is therefore
an important method for the developmental biologist. For many organs it is
difficult to access developing tissue to allow monitoring during ex vivo
culture. The slice culture method allows access to tissue so that
morphogenetic movements can be followed and specific cell populations can be
targeted for manipulation or lineage tracing.
In this paper we describe
a method of slice culture that has been very successful for culture of tooth
germs in a range of species. The method provides excellent access to the
tooth germs, which develop at a similar rate to that observed in vivo,
surrounded by the other jaw tissues. This allows tissue interactions between
the tooth and surrounding tissue to be monitored. Although this paper
concentrates on tooth germs, the same protocol can be applied to follow
development of a number of other organs, such as salivary glands, Meckel’s
cartilage, nasal glands, tongue, and ear.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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11th International
Conference on Tooth Morphogenesis and Differentiation
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تاريخ الإنعقاد:
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May 2013
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بلد ومكان الإنعقاد:
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La Londe Les Maures, France
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طبيعة المشاركة:
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عرض ورقة علمية
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عنوان المشاركة:
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The Nature of Ankylosis
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موجز عن المشاركة:
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The growth of the tooth
and alveolar bone is coordinated so that a specific defined distance keeps
the two apart. We have called this distance, the tooth-bone interface (TBI).
In adults, the TBI accommodates the shock-absorbing properties of the PDL and
distributes the mechanical stress generated during mastication, tooth
movement, and rapid remodelling of teeth. During development the TBI creates
space for the developing tooth to grow, and forms a gap between the tooth and
bone in which the soft tissues of the periodontium can develop [1].
Ossification of the TBI results in ankylosis of the tooth to the bone. The
prevalence of ankylosed teeth can reach up to 40 % depending on the
population [2]. During development ankylosis can to be caused by ossification
of the cells in the TBI or by encroachment of bone into the TBI. We pro- pose
that signaling factors produced by the tooth may be instrumental in
preventing the cells within the TBI from differentiating into osteoblasts,
while the osteoclasts will play a role in preventing encroachment of the
alveolar bone into the space around the tooth. METHODOLOGY: The relative
movement of the bone and tooth during development was followed in slice
culture using the lineage label DiI. The role of osteoclasts in preventing
encroachment of bone was investigated in c-Fos knockout mice. Homozygous
mutants have a cell-autonomous block in osteoclast differentiation and the
teeth fail to erupt [3]. We evaluated the growth of c-Fos knockout (KO) and
heterozygous (+/-) first molars (M1) and the distribution of osteoclasts in
vivo and in tissue explant cultures. PRINCIPAL FINDINGS: During normal
development osteoclasts were found to line the TBI along the alveolar bone
from E14.5. DiI labeling of the alveolar bone showed that the tooth moves
towards the bone as it grows but a TBI was al- ways maintained. In c-Fos
knockouts no TRAP positive cells were observed at birth and the bone started
to invade into the TBI encroaching on the tooth. This invasion could be
followed in culture as the tooth expanded from the cap to the bell stages.
Encroachment of the bone towards the dental papilla was also evident in c-Fos
heterozygous mandibles in culture. DISCUSSION and CONCLUSIONS: Osteoclasts in
the alveolar bone play an essential role in promoting the maintenance of the
TBI, removing bone as the tooth advances and providing the space required to
accommodate the developing tooth. Defects in this process will lead to
ankylosis and may restrict the growth of the tooth.
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المؤتمر (2):
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عنوان المؤتمر:
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7th Annual Meeting of the
Saudi Orthodontic Society SOS
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تاريخ الإنعقاد:
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February 2013
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بلد ومكان الإنعقاد:
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Riyadh, Saudi Arabia
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طبيعة المشاركة:
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عرض ورقة علمية
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عنوان المشاركة:
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Constraints on tooth
growth by the developing alveolar bone
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موجز عن المشاركة:
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The growth of the tooth
and the alveolar bone is co-ordinated so that a studied distance always
separates the two. We have called this distance, the tooth-bone interface (TBI).
In adults the TBI accommodates the shock-absorbing properties of the PDL and
distribute the mechanical stress generated during mastication, tooth movement
and rapid remodelling of teeth. During development, lack of mineralization, a
crucial feature of the TBI, creates the space needed for the developing tooth
to grow and forms a gap between the tooth and bone in which the soft tissues
of the periodontium can develop. The TBI protects the tooth from any
defective fusion with the alveolar bone, which would result in ankylosis. No
studies have been done to understand the signals that maintain the bone free
TBI, or to understand the influence of the TBI on tooth development. We have
investigated the impact of the developing alveolar bone on the size and development
of the mouse first molar (M1). We evaluated the growth of the M1 and the
distribution of the osteoclasts in vivo and in explant cultures using two
methods, isolation of the M1 from the surrounding alveolar bone, and
enhancement of osteoclastogenesis through RANK-RANKL signaling after
treatment with RANKL, an osteoclast activator. The M1 showed a significant
increase in size when cultured without alveolar bone compared to controls.
Similar results were obtained after treatment with RANKL, the RANKL activity
was confirmed by an increase in the number of TRAP-positive osteoclasts. Our
data indicate that both alveolar bone and RANKL regulate tooth size without
altering development and that osteoclasts are indispensable in promoting the
formation of the TBI. We intend to further investigate the interactions
between the tooth and alveolar bone during development, looking at the roles
of BMP, Runx2, Twist, and Periostin, genes involved in TBI formation.
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المؤتمر (3):
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عنوان المؤتمر:
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23rd Mammalian Genetics and
Development Workshop
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تاريخ الإنعقاد:
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November 2012
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بلد ومكان الإنعقاد:
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UCL Institute of Child Health, London, UK
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طبيعة المشاركة:
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عرض ورقة علمية
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عنوان المشاركة:
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Constraints on tooth growth by the developing
alveolar bone
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موجز عن المشاركة:
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The growth of the tooth
and the alveolar bone is co-ordinated so that a studied distance always
separates the two. We have called this distance, the tooth-bone interface (TBI).
In adults the TBI accommodates the shock-absorbing properties of the PDL and
distribute the mechanical stress generated during mastication, tooth movement
and rapid remodelling of teeth. During development, lack of mineralization, a
crucial feature of the TBI, creates the space needed for the developing tooth
to grow and forms a gap between the tooth and bone in which the soft tissues
of the periodontium can develop. The TBI protects the tooth from any
defective fusion with the alveolar bone, which would result in ankylosis. No
studies have been done to understand the signals that maintain the bone free
TBI, or to understand the influence of the TBI on tooth development. We have
investigated the impact of the developing alveolar bone on the size and development
of the mouse first molar (M1). We evaluated the growth of the M1 and the
distribution of the osteoclasts in vivo and in explant cultures using two
methods, isolation of the M1 from the surrounding alveolar bone, and
enhancement of osteoclastogenesis through RANK-RANKL signaling after
treatment with RANKL, an osteoclast activator. The M1 showed a significant
increase in size when cultured without alveolar bone compared to controls.
Similar results were obtained after treatment with RANKL, the RANKL activity
was confirmed by an increase in the number of TRAP-positive osteoclasts. Our
data indicate that both alveolar bone and RANKL regulate tooth size without
altering development and that osteoclasts are indispensable in promoting the
formation of the TBI. We intend to further investigate the interactions
between the tooth and alveolar bone during development, looking at the roles
of BMP, Runx2, Twist, and Periostin, genes involved in TBI formation.
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جوائز التكريم:
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الجائزة (1):
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مسمى الجائزة:
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Best Poster Award
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الجهة المانحة:
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The 6th Saudi Scientific International Conference
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تاريخ منح الجائزة:
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October 2012
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مجال التكريم:
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Best poster titled: “Maintenance of the
tooth-bone interface during development”
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البحث (2):
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عنوان البحث:
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Interactions of the tooth and bone during
development.
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رابط إلى البحث:
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Click here
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تاريخ النشر:
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Dec 2013
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موجز عن البحث:
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BACKGROUND:
Gingival Crevicular Fluid
(GCF) changes occur during orthodontic tooth movement and this could serve as
a potential indicator to the response to active treatment.
AIM:
The objective of the study
is to assess the changes in the GCF volume and the levels of Alkaline
Phosphatase (ALP) during early phase of tooth movement.
METHODS:
20 patients requiring all
first premolar extractions were selected and treated with conventional
straight wire mechanotherapy. Canine retraction was done using Nitinol closed
coil springs. Maxillary canine on one side acted as experimental site while
the contralateral canine acted as control. GCF was collected from around the
canines before initiation of retraction, 1 hour after initiating canine
retraction, 1 day, 7 days, 14 days and 21 days. GCF volume and the ALP levels
were estimated and compared with the control side.
RESULTS:
The results showed
statistically significant changes in the GCF volume and ALP levels on the
7th, 14th and 21st days at the experimental sides. The peak in the activity
occurred on the 14th day of initiation of retraction. The GCF volume and ALP
levels did not show any significant variations at the control sites where no
retraction was done.
CONCLUSIONS:
It can be concluded that
GCF volume and ALP levels may serve as an indicator to assess tooth movement
dynamics in orthodontic therapy. Based on the available data and further
studies, ALP levels in GCF may aid in developing a reliable non-invasive
chair side test for assessing the prognosis and progress of orthodontic
therapy.
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