Anatomical Variation in the Mandibular Foramen in Non-Atrophic and Atrophic Mandibles.

OBJECTIVES: Previous studies of variation in mandibular foramen characteristics with age have involved comparison in different populations, but few data, between non-atrophic and atrophic mandibles are available. The aim of this original article was to compare the position, shape and area of the mandibular foramen between non-atrophic and atrophic mandibles. MATERIAL AND METHODS: Morphometric methods were used to study the mandibular foramen variation. Fifty adult dry mandibles from the laboratory of anatomy were selected. Mandibles were considered non-atrophic if the distance between the base and alveolar ridge was homogeneous and greater than 25 mm in the anterior region and 20 mm in the posterior region. Conversely, mandibles were considered atrophic if that distances were lower than those described to a minimum of 11 mm in all areas. All measurements were performed with a digital caliper. For statistical analysis, the admitted level of significance was 5%. RESULTS: When non-atrophic mandibles were compared to atrophic ones, the mandibular foramen shifted significantly to an anterior position (mean difference [MD]: 4.81 mm; P < 0.0001) and to an inferior position (MD: 3.04 mm; P < 0.0001) and changed from an elliptical shape to round one, with a significant decrease in its area (MD: 3.66 mm2; P < 0.05). CONCLUSIONS: The results indicate that there are significant differences in the position, shape and area of the mandibular foramen between non-atrophic and atrophic mandibles. These data should be considered in anaesthetic techniques and surgical procedures to prevent vascular and nervous lesions.

The Effects of Photobiomodulation Delivered by Light-Emitting Diode on Stem Cells from Human Exfoliated Deciduous Teeth: A Study on the Relevance to Pluripotent Stem Cell Viability and Proliferation.

OBJECTIVE: Photobiomodulation (PBM) can modulate the proliferation of some types of stem cells. However, few reports have addressed the effects of PBM delivered by light-emitting diode (LED) on stem cells obtained from the pulp tissue of deciduous teeth. The aim of the present study was to investigate the effect of PBM delivered by red LED (630 nm, 75 mW, 37 mW/cm2) with different radiant exposures on the cell cycle, mitochondrial membrane potential, and senescence of stem cells from human exfoliated deciduous teeth (SHED). MATERIALS AND METHODS: Cultures were irradiated with LED (2, 4, 8, 16, and 32 J/cm2). After 24 h, the cell cycle and mitochondrial membrane potential of the cultures were evaluated using flow cytometry. Nonirradiated cultures served as control. RESULTS: Cultures irradiated with 16 J/cm2 had higher percentages of cells in the synthesis phase than control cultures (p < 0.05), and no significant differences were found regarding the percentage of cells with viable mitochondria between irradiated and control cultures. No significant difference in cell senescence was found between control cultures and cultures irradiated with 2 or 16 J/cm2. CONCLUSIONS: LED irradiation at 630 nm (37 mW/cm2, 75 mW) with radiant exposure of 16 J/cm2 was capable of inducing a proliferative response in stem cells from the pulp tissue of deciduous teeth without affecting mitochondrial function or inducing senescence.

Ultrastructure of submandibular salivary glands of mouse: TEM and HRSEM observations.

The fine structure of submandibular glands of mouse were analyzed using light microscopy (LM), high resolution scanning electron microscopy (HRSEM), and transmission electron microscopy (TEM) methods. For LM, the specimens were embedded in Spurr resin, stained by toluidin blue solutions. For TEM, the tissues of submandibular salivary glands were fixed with modified Karnovsky solution and postfixed with osmium tetroxide. For HRSEM, the tissues were fixed with 2% osmium tetroxide solution in 1/15M sodium phosphate buffer (pH 7.4). The samples were immersed successively in dymethylsulphoxide and freeze cracked. The maceration was made in diluted osmium tetroxide for 24-48 h. The samples were examined by high resolution scanning electron microscopy. The intracellular components of acinar and ductal cells revealed clearly the Golgi apparatus, rough endoplasmic reticulum, secretory granules, and mitochondria. The end bulbs of Golgi lamellae and flattened cisterns of rough endoplasmic reticulum showed the luminal surface. A few mitochondria were identified intermingling between the rough endoplasmic reticulum and the mitochondriales cristae in three-dimensional HRSEM images. Secretory granules were numerous and presented different sizes. Small granules of ribosomes were attached on cistern surface, measuring 20-25 nm in diameter. Numerous arranged microvilli were found on the luminal surface of secretory canaliculus. The contact surfaces of acinar cells revealed complicated interdigitations by cytoplasmic processes. The mitochondria of duct cells were disposed vertically and surrounded by basal infoldings of plasma membranes. Basement membrane showed a spongy-like structure having an irregular surface with various strands and meshes of fine collagen fibrils.

Transmission Electron Microscopy Study of the Neonatal Rat Tongue Mucosa Treated with Special Attention to the Bacteriae on the Epithelial Cell Membrane

RESUMEN: A través de miscroscopía electrónica de transmisión se examinaron las células del epitelio de la mucosa lingual de ratas Wistar recién nacidas. Los tejidos fueron fijados en solución de Karnovksy modificada e incluidos en resina Spurr. Se obtuvieron delgados cortes de 90 nm y se observaron al microscopio electrónico de transmisión Jeol 1010. Se encontró que las células epiteliales queratinizadas escamosas de la mucosa lingual expuestas al cadmio, presentaron grupos de numerosas bacterias las cuales estaban fijadas a las superficies de las membranas celulares. Los cocos y bacilos estaban fijados a las membranas celulares organizadas en pilas o columnas o al azar, como se aprecia claramente en las imágenes obtenidas a través de la microscopía electrónica de transmisión. Las imágenes mostraron que las bacterias estaban fijadas por estructuras fibrilares desde una a otra y desde las memebranas de las células epiteliales a las bacterias. El grupo control demostró que en las membranas celulares no era evidente la presencia de cadmio.

Effect of cadmium on the floor of the mouth on rats during lactation.

Cadmium (Cd) present in the air, drinking water and food has the potential to affect the health of people, mainly those who live in highly industrialized regions. Cd affects placental function, may cross the placental barrier and directly modify fetal development. It is also excreted into milk. The body is particularly susceptible to Cd exposure during perinatal period. The effect on rat oral epithelium (floor of the mouth) after continuous exposure to drinking water containing low levels of Cd during lactation was studied. Female rats were supplied with ad libitum drinking water containing 300 mg/l of CdCl2 throughout the whole lactation period. Control animals received a similar volume of water without Cd. Lactating rats (21 day-old) were killed by lethal dose of anesthetic. The heads were retrieved, fixed in "alfac" solution (alcohol, acetic acid and formaldehyde) for 24 h, serially sectioned in frontal plane, at the level of the first molars. The 6 micro m sections were then stained with hematoxylin and eosin. Nuclear epithelium parameters were estimated, as well as cytoplasm and cell volume, nucleus/cytoplasm ratio, numeric and surface densities, and epithelial thickness. Mean body weight was 34.86 g for the control group and 18.56 g for the Cd-treated group. Histologically, the floor of the mouth epithelium was thinner in the treated group, with smaller and more numerous cells. In this experiment, Cd induced epithelial hypotrophy, indicating a direct action in oral mucosa cells, besides retarded development of the pups.

Effect of cadmium on the floor of the mouth on rats during lactation

O cádmio (Cd) do ar, da água e dos alimentos tem o potencial de afetar a saúde das pessoas, principalmente daquelas que vivem em regiões altamente industrializadas. O Cd afeta a função placentária, podendo atravessar a barreira placentária e provocar distúrbios no desenvolvimento fetal. Pode, também, ser excretado pelo leite. O organismo é particularmente susceptível à exposição ao Cd no período perinatal. Foi estudado o efeito da intoxicação por Cd no epitélio do soalho da boca de ratos expostos a baixos níveis do metal na água de bebedouro, durante a lactação. As ratas receberam água ad libitum contendo 300 mg/l de CdCl2 durante toda a lactação. Os animais controle receberam um volume similar de água sem Cd. Os filhotes foram sacrificados por sobredosagem anestésica no 21º dia. As cabeças dos animais foram separadas, fixadas em solução de "alfac" (álcool, ácido acético e formaldeído) por 24 h, seccionadas seriadamente em planos frontais ao nível dos primeiros molares, e os cortes de 6 µm foram corados com hematoxilina-eosina. Foram estimados os parâmetros nucleares do epitélio, assim como os volumes citoplasmático e celular, a relação núcleo/citoplasma, as densidades numérica e superficial e a espessura epitelial. O peso corporal médio do filhote foi de 34,86 g no grupo controle e 18,56 g no tratado. Histologicamente, o epitélio dos animais tratados mostrou-se adelgaçado, constituído de células abundantes e menores. Neste experimento, o Cd ocasionou um quadro de hipotrofia epitelial, indicando uma ação direta nas células epiteliais da mucosa oral, além de retardar o desenvolvimento dos filhotes intoxicados.

Efectos del cadmio en la mucosa yugal de la rata durante la lactancia: estudio morfológico e histométrico / Effects of cadmium on the rat jugal mucosa during lactation: morphological and histometrical study

El cadmio del aire, agua y alimentos tiene potencial de afectar la salud de las personas, principalmente de aquellas que viven en regiones industrializadas. El cadmio afecta la función placentaria, pudiendo atravesar la barrera trofoblástica y provocar alteraciones en el desarrollo del feto; puede, también, ser excretado por la leche. El organismo es particularmente susceptible a la exposición al cadmio en el periodo perinatal. Se estudió el efecto de la intoxicación por cadmio en el epitelio vestibular y suelo de la boca de ratas expuestas a niveles bajos de cadmio en el agua del bebedero, durante la lactancia. Las ratas recibieron agua ad libitum conteniendo 300 mg/l de CdCl2 durante los 21 días de lactancia. Los animales controles recibieron un volumen similar de agua sin cadmio. Las crías fueron sacrificadas mediante sobredosis anestésica en el 21 día. Las cabezas de los animales fueron separadas, fijadas en solución de alfac. Las regiones del paladar y de la mandíbula fueron cortadas seriadamente en planos frontales, a nivel de los primeros molares, efectuándose cortes de 6 µm de grosor, los cuales fueron teñidos con H-E. Los parámetros nucleares del epitelio fueron estimados, así como también, los volúmenes citoplasmático y celular, relación núcleo-citoplasma, densidad numérica y superficial, y el espesor del epitelio. El peso corporal medio de las crías fue de 34,86 g en el grupo control y de 18,56 en el grupo tratado. Histológicamente, el epitelio se mostró adelgazado, constituido por células abundantes y menores. En el presente experimento, el cadmio ocasionó un cuadro de hipotrofia epitelial, indicando una acción directa en las células epiteliales de la mucosa oral, además de provocar el retardo del desarrollo de las crías intoxicadas.