Fate of Worn‐Out Functional Teeth in the Upper Jaw Dentition of Sicyopterus japonicus (Gobioidei: Sicydiinae) During Tooth Replacement

Abstract

Mochizuki and Fukui (Jpn J Ichthyol 30 () 27-36) studied the development and replacement of the upper jaw teeth in a Japanese fish species, Sicyopterus japonicus (Gobioidei: Sicydiinae), and they reported that worn-out functional teeth in the upper jaw were not shed outside the skin but were taken into the soft tissue of the upper jaw and completely resorbed there. To date, however, this phenomenon appears poorly documented. Furthermore, the mechanism for the resorption of these teeth remains to be determined. In this study, we examined this phenomenon by using 3D microcomputed tomography (m-CT), scanning electron microscopy (SEM), and various techniques of light (LM) and electron (EM) microcopy. This study demonstrated that the upper jaw dentition of this fish was more or less simultaneously replaced with the replacement occurring during short time periods and that the lingual movement of the replacement teeth to the functional tooth position advanced simultaneously in a given row. Furthermore, our study also revealed that many worn-out functional teeth were engulfed by the oral epithelium, invaginated into the lingual shallow ditch of the premaxilla, and were resorbed/degraded completely by numerous foreign body giant cells rather than by odontoclasts during periods of at least three intervals of tooth replacement. The complete resorption/degradation of worn-out functional teeth in the soft tissue of the upper jaw suggests the possibility of the reuse of their components (minerals such as Ca and P, including Fe) for rapid and successional production of new replacement teeth in the upper jaw of adult S. japonicus. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:111-124, 2018. © 2017 Wiley Periodicals, Inc.

Comparative anatomy study of teeth types in Barracauda and Tilapia fish

“…6 -8). This description agrees with many authors (Geerinckx et al, 2007 andSahara et al, 2018) in herbivore feeding habit of fish. Also, it agrees with Alsafy et al (2018) in their description on the upper and lower pharyngeal teeth of Bagrus Bayad which is carnivorous nature.…”

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“…According to the location of the tooth germ and the attachment bone, tooth replacement can be categorized as intraosseous or extraosseous. In most teleosts with extraosseous replacement, the previous generation teeth were resorbed by macrophage or osteoclast activity on the lingual or labial side, and the adjacent successor tooth then migrated to the positions of previous teeth before eruption and the completion of replacement (Sahara et al, 2018; Trapani, 2001). Successor tooth germ entry into the interior of the supporting bone through a replacement pore is an indicator of intraosseous replacement.…”

Continuous tooth replacement: what can teleost fish teach us?

“…However, in Atlantic salmon, the tooth is actively broken down inside the oral epithelium but not shed (Witten et al ., 2005). Likewise, in the gobioid Sicyopterus japonicus , worn‐out teeth are engulfed by the oral epithelium, and resorbed/degraded completely by numerous multinucleated, foreign body giant cells (Sahara et al ., 2018). Defective tooth resorption has no influence on tooth development.…”