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نوع الوثيقة |
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مقال في مجلة دورية |
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عنوان الوثيقة |
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A comarative study on the effect of Emdogain and Calcium Hydroxide on apical closure in young permant teeth of dogs A comarative study on the effect of Emdogain and Calcium Hydroxide on apical closure in young permant teeth of dogs |
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لغة الوثيقة |
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الانجليزية |
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المستخلص |
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Traumatic injuries to young permanent teeth are not uncommon and are
said to affect 30% of children. (1) The majority of these incidents occurs
before root formation is complete( 2) and may result in pulpal
inflammation or necrosis.
Apexification is a method of inducing root end closure of an incompletely
formed non vital permanent tooth by removing the coronal non vital
radicular tissue just short of the root end and placing in the canal a
suitable biocompatible agent such as calcium hydroxide (3) or MTA. (4)
The rationale is to establish an apical stop that would enable the root
canal to be filled.
Because of the important role of Hertwig's epithelial root sheath in
continued root development after injury, every effort should be made to
maintain its viability. It is thought to provide a source of undifferentiated
cells that could give rise to further hard tissue formation. It may also
protect against the in growth of ligament cells into the root canal, which
would result in intracanal bone formation and arrest of root
development.(5) Complete destruction of Hertwig's epithelial root sheath
results in cessation of normal root development. This does not however
mean that there is an end to deposition of hard tissue in the region of the
root apex. Once the sheath has been destroyed there can be no further
differentiation of odontoblasts. However, hard tissue can be formed by
cementoblasts that are normally present in the apical region and by
fibroblasts of the dental follicle and periodontal ligament that undergo
differentiation after the injury to become hard tissue producing cells. (6)
Cooke and Robotham (7) hypothesize that the remnants of Hertwig's
epithelial root sheath, under favorable conditions, may organize the apical
mesodermal tissue into root components.
Although a variety of materials have been proposed for induction of
apical barrier formation, calcium hydroxide has gained the widest
acceptance. As the calcium ions from calcium hydroxide dressing do not
come from calcium hydroxide but from the blood stream(8,9) ,the
mechanism of action of calcium hydroxide remains controversial.
Holland et al (10) has demonstrated that the reaction of the periapical
tissues to calcium hydroxide is similar to that of pulp tissue. It produces
a multilayered necrosis with subjacent mineralization. Schroder and
Granath (11) have postulated that the layer of firm necrosis generates a
low-grade irritation of the underlying tissue sufficient to produce a matrix
that mineralizes. Calcium is attracted to the area and mineralization of
newly formed collagenous matrix is initiated from the calcified foci. It
appears that the high pH of calcium hydroxide is an important factor in its
ability to induce hard tissue formation. (12)
Controversy exists as to whether or how often the calcium hydroxide
should be changed. (13-16)
Abbot (17) suggests that the ideal time to replace a dressing depends on the
stage of treatment and the size of the foramen opening. This must be
assessed for each individual tooth at each stage of development.
Enamel matrix derivative (EMD) has been shown to enhance new
connective tissue attachment, defined as new cementum with inserting
collagen fibres, in addition to new alveolar bone formation in both
animals and humans. (18-22 ) EMD has been successfully employed to
incite natural cementogenesis to restore a fully functional periodontal
ligament, and alveolar bone in patients with advanced periodontitis. (24)
Moreover, EMD was reported to eliminate inflammatory root resorption
and infection in young replanted permanent teeth. (25)
The emdogain induced process actually mimic parts of normal
odontogenesis , and it is believed the EMD proteins participate in the
reciprocal ectodermal – mesenchymal signaling that control and pattern
these processes. (18,19 )
Since exposure to enamel proteins takes place during tooth development
in early childhood, tolerance should normally be induced and protein
recognized by the immune system as "self" proteins. Changes in the
protein structure and conformation or occurrence of unrelated proteins
would be possible sources for an immune response against the product.
However, enamel proteins have stayed virtually unchanged during
evolution. (26 ) Zettersom et al (21) demonstrated a very low, if any
immunogenic potential of EMD when applied to the dental root surface in
conjunction with periodontal surgery . The same was reported by Petmaki
et al (26) whose study indicated a restricted immune response at
concentrations far higher than those used in clinical practice.
The present study was performed to test if emdogain could induce apical
closure (barrier) without eliciting adverse side effects in immature
permanent teeth of dogs. Conventional treatment with calcium hydroxide
is commonly used as a control in similar experiments. |
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ردمد |
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0 |
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اسم الدورية |
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E.D.J |
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المجلد |
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52 |
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العدد |
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1 |
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سنة النشر |
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2006 هـ
2006 م |
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نوع المقالة |
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مقالة علمية |
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تاريخ الاضافة على الموقع |
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Thursday, December 6, 2007 |
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الباحثون
| نادية عزيز | aziz, Nadia | باحث رئيسي | دكتوراه | |
| نيفين بكري | Bakry, Niveen | باحث مشارك | دكتوراه | |
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