periodontium

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/14 12:32:29」(JST)

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Periodontium
The tissues of the periodontium combine to form an active, dynamic group of tissues. The alveolar bone (C) is surrounded for the most part by the subepithelial connective tissue of the gingiva, which in turn is covered by the various characteristic gingival epithelia. The cementum overlaying the tooth root is attached to the adjacent cortical surface of the alveolar bone by the alveolar crest (I), horizontal (J) and oblique (K) fibers of the periodontal ligament.
Details
Latin	parodontium
Identifiers
TA	A05.1.03.058 A03.1.03.002
FMA	56665
Anatomical terminology

Periodontium refer to the specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones. The word comes from the Greek terms peri-, meaning "around" and -odons, meaning "tooth." Literally taken, it means that which is "around the tooth". Periodontics is the dental specialty that relates specifically to the care and maintenance of these tissues. It provides the support necessary to maintain teeth in function. It consists of four principal components namely:

• Gingiva
• Periodontal ligament (PDL)
• Cementum
• Alveolar bone

Each of these components is distinct in its location, tissue architecture, biochemical and chemical composition. They have their own distinct functions that are capable of adaptation during the life of the structure. For example as teeth respond to forces or migrate mesially, bone resorbs on the pressure side and is added on the tension side. Cementum similarly adapts to wear on the occlusal surfaces of the teeth by apical deposition. The periodontal ligament in itself is an area of high turnover that allows the tooth not only to be suspended in the alveolar bone but also to respond to the forces. Thus, although seemingly static and having functions of their own, all of these components function as a single unit.

External forces and the periodontium

The periodontium exists for the purpose of supporting teeth during their function and it depends on the stimulation it receives from the function for preservation of its structure. Therefore a constant state of balance always exists between the periodontal structures and the external forces.

Alveolar bone undergoes constant physiologic remodeling in response to external forces particularly occlusal forces. Bone is removed from areas where it is no longer needed and added to areas where it is needed. The socket wall reflects the responsiveness to the external forces. Osteoblasts and newly formed osteoid line the areas of tension whereas line of compression are lined by osteoclasts. The forces also influence the number density and alignment of trabeculae inside the bone. The bony trabeculae are aligned in the path of tensile and compressive stresses to provide maximum resistance to occlusal forces with a minimum of bone substance. When forces are increased the bony trabeculae also increase in number and thickness and bone is added to the external surfaces.

The periodontal ligament depends on stimulation provided by function to preserve its structure. Within physiologic limits the PDL can accommodate increased function with increase in its width. Forces that exceed the adaptive capacity of the periodontium produce injury called trauma from occlusion. When occlusal forces are reduced the PDL atrophies, appearing thinned. This phenomenon is called disuse atrophy.

References

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English Journal

• Expression of Wnt3a, Wnt10b, β-catenin and DKK1 in periodontium during orthodontic tooth movement in rats.

• Lu J1, Duan Y1, Zhang M1, Wu M1, Wang Y1.
• Acta odontologica Scandinavica.Acta Odontol Scand.2016 Apr;74(3):217-23. doi: 10.3109/00016357.2015.1090011. Epub 2015 Sep 28.
• OBJECTIVE: To investigate the expression of Wnt3a, Wnt10b, β-catenin and DKK1 in the periodontal ligament (PDL) during orthodontic tooth movement (OTM) in rats.MATERIALS AND METHODS: Nickel-titanium closed-coil springs were used to deliver an initial 50 g mesial force to the left maxillary first mo
• PMID 26414930

• Caffeine may enhance orthodontic tooth movement through increasing osteoclastogenesis induced by periodontal ligament cells under compression.

• Yi J1, Yan B2, Li M1, Wang Y3, Zheng W4, Li Y5, Zhao Z1.
• Archives of oral biology.Arch Oral Biol.2016 Apr;64:51-60. doi: 10.1016/j.archoralbio.2015.12.009. Epub 2016 Jan 4.
• OBJECTIVE: Caffeine is the kernel component of coffee and has multiple effects on bone metabolism. Here we aimed to investigate the effects of caffeine intake on orthodontic tooth movement (OTM).DESIGN: (1) In the in vivo study, two groups comprising 15 randomly assigned rats each underwent orthodon
• PMID 26773691

• Immunohistochemical localization of tenascin-C in rat periodontal ligament with reference to alveolar bone remodeling.

• Sato R1, Fukuoka H2, Yokohama-Tamaki T1, Kaku M3, Shibata S4.
• Anatomical science international.Anat Sci Int.2016 Mar;91(2):196-206. doi: 10.1007/s12565-015-0285-y. Epub 2015 May 9.
• We investigated the immunohistochemical localization of tenascin-C in 8-week-old rat periodontal ligaments. Tenascin-C immunoreactivity was detected in zones along with cementum and alveolar bone, and more intensely on the resorption surface of alveolar bone than on the formation surface. On the res
• PMID 25957016

Japanese Journal

• 4 VCAM-1はRANKLが誘導する破骨細胞分化を増強する(第543回大阪歯科学会例会)

• 林 寛,氏井 庸介,合田 征司,松本 尚之
• 歯科医学 77(2), 96, 2014-09-25
• … During orthodontic therapy, osteoclast precursors such as monocytes and macrophages migrate from vessels into the periodontium and then differentiate into osteoclasts, causing bone resorption. …
• NAID 110009857559

• Mechano-regulation of collagen biosynthesis in periodontal ligament

• ,
• Journal of Prosthodontic Research 58(4), 193-207, 2014
• … Periodontal ligament (PDL) plays critical roles in the development and maintenance of periodontium such as tooth eruption and dissipation of masticatory force. …
• NAID 130004714115

• Periodontal tissue regeneration by transplantation of rat adipose-derivedstromal cells in combination with PLGA-based solid scaffolds

• , , , , , , , , , , , , ,
• Biomedical Research 35(2), 91-103, 2014
• … Regeneration of damaged periodontium is challenging due to its multi-tissue composition. …
• NAID 130004470864

Related Links

• Periodontium | Define Periodontium at Dictionary.com

periodontium per·i·o·don·ti·um (pěr'ē-ə-dŏn'shē-əm) n. pl. per·i·o·don·ti·a (-shē-ə, -shə) The tissues that surround and support the teeth, including the gums, cementum, periodontal ligament, and alveolar and supporting bone. Also ...

• periodontium - definition of periodontium by Medical dictionary

periodontium /peri·odon·ti·um/ (-don´she-um) pl. periodon´tia the tissues investing and supporting the teeth, including the cementum, periodontal ligament, alveolar bone, and gingiva. Periodontium, showing the periodontal ligament ...

Related Pictures

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★リンクテーブル★

リンク元	「periodontal」「歯周組織」「periodontal tissue」

「periodontal」

　　[★]

• adj.

• 歯周の、歯周組織の、歯周部の

関

endodontic、periodontal tissue、periodontium

「歯周組織」

　　[★]

英

periodontal tissue、periodontium、periodontal

関

歯根膜、歯周、歯周部

「periodontal tissue」

　　[★]

• 歯周組織

関

periodontal、periodontium