Morphology of the Dentin Structure of Sloths Bradypus tridactylus: A Light and Scanning Electron Microscopy Investigation

Abstract

The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species.

Anatomical and histological characteristics of teeth in agouti (Dasyprocta prymnolopha Wagler, 1831)

“…The organization of dental tissues observed by SEM and LM showed many similarities compared to other mammals previously described in the literature (Forssell-Ahlberg et al 1975, Kroon et al 1986, Pough et al 2003, Santana et al 2013.…”

“…In this research, our methodology did not allow SEM observation to look inside these tubules, but the findings suggest the same internal organization as found in other animals (Forssell-Ahlberg et al 1975, Brännström & Garberoglio 1972, Muylle et al 2001. The tubular pattern found with individual tubules is characteristic of a pattern of dentin termed orthodentine found in the dentin of some mammals, as depicted through Santana et al (2013). Unlike other types of dentin such as vasodentina, this dentin has some morphological variations with respect to the direction of the dentinal tubules (sometimes it can present itself very much branched or deformed in some species), the most common among mammals.…”

“…Then, the sections were dehydrated in absolute alcohol, cleared with xylol, and coverslipped (Santana et al 2013). The most representative images were obtained using a digital camera (Olympus Evolt E-330, Center Valley, PA, USA) attached to a light microscope (Olympus BX41, Center Valley, PA, USA).…”

“…The cleaning process continued with immersion in 17% EDTA solution for 10 sec to remove residue fragmentation, and again rinsed with distilled water in ultrasonic bath (Santana et al 2013).…”

Morfologia radicular da dentição permanente de Sapajus apella: morfometria, anatomia macroscópica, ultraestrutura e propriedades físicas

“…Para a análise ultraestrutural, alguns dentes foram clivados longitudinalmente. As hemi--secções de melhor integridade foram imersas em hipoclorito de sódio a 1% por 1 minuto para remover resíduos de material orgânico aderido à parede dentinária, sendo em seguida imersas em EDTA a 17% por 10 segundos, para remover detritos provenientes do seccionamento, passando por lavagem final de água destilada em banheira ultrassônica por 30 segundos, segundo protocolo estabelecido por Santana et al (2013). Os dentes foram então desidratados em soluções crescentes de álcool, secos em temperatura ambiente, metalizados com platina e avaliados em microscópio eletrônico de varredura modelo LEO-1430 nas condições de análise para as imagens de elétrons secundários de: Corrente do Feixe de Elétrons = 90µA; Voltagem de Aceleração Constante = 15Kv e Distância de Trabalho = 10mm.…”