* Timing of Mouse Molar Formation Is Independent of Jaw Length Including Retromolar Space.
- For humans and other mammals to eat effectively, teeth must develop properly inside the jaw. Deciphering craniodental integration is central to explaining the timely formation of permanent molars, including third molars which are often impacted in humans, and to clarifying how teeth and jaws fit, function and evolve together. A factor long-posited to influence molar onset time is the jaw space available for each molar organ to form within. Here, we tested whether each successive molar initiates only after a minimum threshold of space is created via jaw growth. We used synchrotron-based micro-CT scanning to assess developing molars in situ within jaws of C57BL/6J mice aged E10 to P32, encompassing molar onset to emergence. We compared total jaw, retromolar and molar lengths, and molar onset times, between upper and lower jaws. Initiation time and developmental duration were comparable between molar upper and lower counterparts despite shorter, slower-growing retromolar space in the upper jaw, and despite size differences between upper and lower molars. Timing of molar formation appears unmoved by jaw length including space. Conditions within the dental lamina likely influence molar onset much more than surrounding jaw tissues. We theorize that molar initiation is contingent on sufficient surface area for the physical reorganization of dental epithelium and its invagination of underlying mesenchyme.
=>茂み, 成長, 増加, 発展, 栽培, 腫よう, 成長物
Overview of noun growth
The noun growth has 7 senses (first 5 from tagged texts)
1. (37) growth, growing, maturation, development, ontogeny, ontogenesis -- ((biology) the process of
an individual organism growing organically; a purely biological unfolding of events involved in an
organism changing gradually from a simple to a more complex level; "he proposed an indicator of
osseous development in children")
2. (20) growth -- (a progression from simpler to more complex forms; "the growth of culture")
3. (3) increase, increment, growth -- (a process of becoming larger or longer or more numerous or
more important; "the increase in unemployment"; "the growth of population")
4. (3) growth -- (vegetation that has grown; "a growth of trees"; "the only growth was some salt
grass")
5. (1) emergence, outgrowth, growth -- (the gradual beginning or coming forth; "figurines presage
the emergence of sculpture in Greece")
6. growth -- ((pathology) an abnormal proliferation of tissue (as in a tumor))
7. growth -- (something grown or growing; "a growth of hair")
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