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The role of hypoxia in orthodontic tooth movement.

Niklas A, Proff P, Gosau M, Römer P - Int J Dent (2013)

Bottom Line: Orthodontic forces are known to have various effects on the alveolar process, such as cell deformation, inflammation, and circulatory disturbances.As a result, bone remodeling is induced, facilitating orthodontic tooth movement.However, orthodontic forces not only have cellular effects but also induce vascular changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, University Medical Center Regensburg, 93053 Regensburg, Germany.

ABSTRACT
Orthodontic forces are known to have various effects on the alveolar process, such as cell deformation, inflammation, and circulatory disturbances. Each of these conditions affecting cell differentiation, cell repair, and cell migration, is driven by numerous molecular and inflammatory mediators. As a result, bone remodeling is induced, facilitating orthodontic tooth movement. However, orthodontic forces not only have cellular effects but also induce vascular changes. Orthodontic forces are known to occlude periodontal ligament vessels on the pressure side of the dental root, decreasing the blood perfusion of the tissue. This condition is accompanied by hypoxia, which is known to either affect cell proliferation or induce apoptosis, depending on the oxygen gradient. Because upregulated tissue proliferation rates are often accompanied by angiogenesis, hypoxia may be assumed to fundamentally contribute to bone remodeling processes during orthodontic treatment.

No MeSH data available.


Related in: MedlinePlus

Vascularisation of the dental pulp and the alveolar bone. Blood vessels entering the tooth via the apical constriction.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig2: Vascularisation of the dental pulp and the alveolar bone. Blood vessels entering the tooth via the apical constriction.

Mentions: The dental pulp is divided into two major portions, the crown's pulp and the root. The pulp consists of glycosaminoglycans as a basic element, in which the pulpal cells, such as pulp fibroblasts, odontoblasts, and pulpal stem cells, are embedded [51]. A dense network of arteries, veins, arterioles, venules, and capillaries ensures the high vascularization of the pulp tissue. However, almost all blood vessels enter a tooth via the apical constriction (Figure 2), making it a trouble spot for pulpal blood supply [52, 53]. Pulpal blood vessels are usually accompanied by other functional structures, such as nerves or lymph vessels [54, 55]. The nociceptive innervation of the pulp is mainly based on A-β-fibers, A-δ-fibers, and C-fibers [56], whereas the vasomotoric nerve fibers of the vegetative nervous system control the muscular tonus of pulpal arterioles and therefore contribute to the regulation of pulpal blood flow [54]. Venules of the dental pulp are known to have very thin walls that tend to collapse in case of high pulpal pressure. In this context, it is also interesting that vasodilation induced by inflammation mediators, such as PGE2, seems to have different effects in the dental pulp as in other tissues. By increasing pulpal pressure and therefore hydraulically inducing secondary vasoconstriction, vasodilation might halt the spread of infections, if induced in a very localized area; however, vasodilation may also facilitate necrosis in cases of generalization [54]. Tripuwabhrut et al. [57] induced severe root resorption by applying intermitting tensile loads of 50 g onto 15 first molars in rats for up to 30 days to investigate inflammatory patterns in the dental pulp and the PDL. The investigators found typical signs of inflammation in the compressed PDL, such as immigration of macrophages, monocytes, and dendritic cells. Increased angiogenesis could also be observed in root areas affected by resorption. Nevertheless, no new formation of nerve structures as usually seen in inflamed periodontal and pulpal tissues could be observed [57].


The role of hypoxia in orthodontic tooth movement.

Niklas A, Proff P, Gosau M, Römer P - Int J Dent (2013)

Vascularisation of the dental pulp and the alveolar bone. Blood vessels entering the tooth via the apical constriction.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818850&req=5

fig2: Vascularisation of the dental pulp and the alveolar bone. Blood vessels entering the tooth via the apical constriction.
Mentions: The dental pulp is divided into two major portions, the crown's pulp and the root. The pulp consists of glycosaminoglycans as a basic element, in which the pulpal cells, such as pulp fibroblasts, odontoblasts, and pulpal stem cells, are embedded [51]. A dense network of arteries, veins, arterioles, venules, and capillaries ensures the high vascularization of the pulp tissue. However, almost all blood vessels enter a tooth via the apical constriction (Figure 2), making it a trouble spot for pulpal blood supply [52, 53]. Pulpal blood vessels are usually accompanied by other functional structures, such as nerves or lymph vessels [54, 55]. The nociceptive innervation of the pulp is mainly based on A-β-fibers, A-δ-fibers, and C-fibers [56], whereas the vasomotoric nerve fibers of the vegetative nervous system control the muscular tonus of pulpal arterioles and therefore contribute to the regulation of pulpal blood flow [54]. Venules of the dental pulp are known to have very thin walls that tend to collapse in case of high pulpal pressure. In this context, it is also interesting that vasodilation induced by inflammation mediators, such as PGE2, seems to have different effects in the dental pulp as in other tissues. By increasing pulpal pressure and therefore hydraulically inducing secondary vasoconstriction, vasodilation might halt the spread of infections, if induced in a very localized area; however, vasodilation may also facilitate necrosis in cases of generalization [54]. Tripuwabhrut et al. [57] induced severe root resorption by applying intermitting tensile loads of 50 g onto 15 first molars in rats for up to 30 days to investigate inflammatory patterns in the dental pulp and the PDL. The investigators found typical signs of inflammation in the compressed PDL, such as immigration of macrophages, monocytes, and dendritic cells. Increased angiogenesis could also be observed in root areas affected by resorption. Nevertheless, no new formation of nerve structures as usually seen in inflamed periodontal and pulpal tissues could be observed [57].

Bottom Line: Orthodontic forces are known to have various effects on the alveolar process, such as cell deformation, inflammation, and circulatory disturbances.As a result, bone remodeling is induced, facilitating orthodontic tooth movement.However, orthodontic forces not only have cellular effects but also induce vascular changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, University Medical Center Regensburg, 93053 Regensburg, Germany.

ABSTRACT
Orthodontic forces are known to have various effects on the alveolar process, such as cell deformation, inflammation, and circulatory disturbances. Each of these conditions affecting cell differentiation, cell repair, and cell migration, is driven by numerous molecular and inflammatory mediators. As a result, bone remodeling is induced, facilitating orthodontic tooth movement. However, orthodontic forces not only have cellular effects but also induce vascular changes. Orthodontic forces are known to occlude periodontal ligament vessels on the pressure side of the dental root, decreasing the blood perfusion of the tissue. This condition is accompanied by hypoxia, which is known to either affect cell proliferation or induce apoptosis, depending on the oxygen gradient. Because upregulated tissue proliferation rates are often accompanied by angiogenesis, hypoxia may be assumed to fundamentally contribute to bone remodeling processes during orthodontic treatment.

No MeSH data available.


Related in: MedlinePlus