ABSTRACT
La erupción dental es un proceso estrictamente regulado y programado espacial y temporalmente. El objetivo del trabajo fue estudiar el efecto de la exposición prenatal a fluoruro de sodio (NaF) sobre los eventos morfológicos y celulares que ocurren en el hueso supracoronal del primer molar de crías de rata durante la etapa preeruptiva. Se emplearon crías (n=6-8 por grupo) provenientes de madres que bebieron crónicamente agua con diferentes concentraciones de F- en forma de NaF durante la gestación y lactancia: control y NaF (50 mg/L). En cortes histológicos de la mandíbula de crías de 3 y 10 días se analizaron parámetros de histomorfometría estática en la zona supracoronal de la canastilla ósea a la altura del primer molar inferior: volumen óseo trabecular [BV/TV (%)], número de osteoclastos por milímetro (N.Oc/mm) y las variables indirectas: número de trabéculas [Tb.N (1/mm)], espesor [Tb.Th (µm)] y separación trabecular [Tb.Sp (µm)]. En crías de 15 días se midió el grado de erupción [TED (µm)] del primer molar inferior. Los resultados se analizaron con el test "t" de Student considerando diferencias significativas a p<0,05. El análisis histomorfométrico demostró un incremento en el BV/TV (%) del hueso supracoronal (p<0,01) asociado con disminución del N.Oc/mm (p<0,01) en crías de 3 y 10 días expuestas prenatalmente al F-. El grado de erupción dental fue menor en animales expuestos prenatalmente al F- en comparación con los controles (p<0,01). En conclusión, los resultados observados en la mandíbula de crías expuestas durante la etapa prenatal y posnatal temprana al F- sugieren un efecto disruptivo sobre la actividad resortiva necesaria para formación del canal eruptivo. (AU)
Tooth eruption is a tightly regulated and spatially and temporally programmed process. The aim of this study was to examine the effect of prenatal NaF exposure on the morphological and cellular events that occur in the supracoronal area of bony crypt of the first rat molar during the preeruptive stage. Offspring from two groups of rats were used (6-8 per group): Control and 50 mg/L NaF. The treatment was performed during pregnancy and lactation. Suckling pups were euthanized at 3-, 10- and 15-days-old by cervical dislocation. Mandibles were removed and histologically processed to obtain buccolingual sections stained with H&E. In sections of first mandibular molar of 3- and 10-days-old pups, the following static histomorphometric parameters were evaluated: trabecular bone volume [BV/TV (%)] and number of osteoclasts (N.Oc/mm). Also, indirect parameters were obtained: trabecular number [Tb.N (1/mm)], trabecular thickness [Tb.Th (µm)], and trabecular separation [Tb.Sp (µm)]. The degree of tooth eruption [TED (µm)] was determined. Results are expressed as mean ± SE and analyzed by Student t-test. Histomorphometric analysis showed an increase in the BV/TV (%) of the bone crypt of 3- and 10- days-old pups exposed to NaF (p <0.01); this increase was associated with a decrease in the N.Oc/mm (p <0.01). TED of mandibular first molar was lower in prenatal NaF exposed group than in control group (p<0.01). In conclusion, the increased BV/TV and the lower N.Oc observed in the bone crypt of 3- and 10- days-old pups from mothers treated with NaF suggested a disruptive effect triggered by F- on the formation events of the eruptive pathway in the offspring. (AU)
Subject(s)
Humans , Animals , Male , Female , Infant , Child, Preschool , Rats , Sodium Fluoride/adverse effects , Tooth Eruption , Osteoclasts/cytology , Prenatal Exposure Delayed Effects , Sodium Fluoride/administration & dosage , Sodium Fluoride/metabolism , Sodium Fluoride/urine , Sodium Fluoride/chemical synthesis , Rats, Wistar , Mandible/anatomy & histology , Molar/growth & development , Fluorosis, Dental/diagnosisABSTRACT
The aim of this work was to analyse the parasympathetic control of submandibular saliva secretory response to cholinergic and peptidergic agonists in rats chronically exposed to constant light or repeated immobilization. Thirty two adult male Wistar rats were used: LL (8 rats exposed to constant light for 20 days), IMO (8 rats submitted to 14:10 h light: dark cycle and immobilized 2 hours daily for 7 days), and control (16 rats not exposed to stress and submitted to 14:10 hours light:dark cycle). Saliva was collected under anesthesia from the salivary ducts of submandibular glands under increasing doses of methacholine and substance P. Secretory responses (µg/saliva/mg dry weight gland) to methacholine were significantly higher in LL and IMO groups compared to control for the following doses (µg/kg body weight): 3 (153±9 versus 46±3, p<0.001 and 76±3 versus 40±3, p<0.001), 10 (379±23 versus 277±8, p<0.001 and 275±19 versus 250±10, p<0.01) and 30 (729±25 versus 695±19, p<0.05 and 1008±39 versus 640±20, p<0.001). Also, responses to substance P were significantly increased in LL and IMO groups compared to control for the following doses: 0.2 (80±3 versus 30±3, p<0.01 and 94±16 versus 31±3, p<0.001), 0.5 (328±20 versus 231±16, p<0.01 and 531±31 versus 219±25,p<0.001), 1 (681±35 versus 547±30, p<0.01 and 1031±63 versus 563±53, p<0.001), and 5 (2222±88 versus 1868±59, p<0.01 and 3230±145 versus 1921±218, p<0.001). In conclusion, supersensitivity of secretory response to both agonists suggests that chronic exposure of rats to stressors capable of activating the sympathetic adrenal system promotes inhibition of the parasympathetic control of salivary secretion.
Subject(s)
Animals , Rats , Saliva/metabolism , Salivary Glands/physiology , Salivation/physiology , Cholinergic Agonists/administration & dosage , Adrenergic Agonists/administration & dosage , Phototherapy , Rats, Wistar , Anesthesia , LightABSTRACT
Abstract: objective colour determination is based on calculating the colorimetricdistance (Delta E) within a colour space. So far, the most used colour space in dentistry is CIE L*a*b (Comission Internationale de l´Éclairage). CIE L*C*h* has been recently developed, showing a better correlation with the perception of the human eye. Objective: To determine the ability of an in vitro remineralisation substance to blend the colour of white spot lesions (WSL) with sound enamel, determining Delta E by using the CIE L*C*h* colour space. Methods: In vitro WSL was generated by immersing 10 samples obtained from human third molars in a demineralization solution for 72h. Amorphous calcium phosphate stabilized by casein phosphopeptide (CPP-ACP) was then applied for 60 days while maintaining the samples in artificial saliva at 37ºC. To evaluate the colour of enamel, images were taken from the samples placed in specifically designed silicone moulds after generating the WSL (pre-stage) and after remineralisation by scanning, applying the colorimetric distance equation (Delta E*CMC) according to the Colour Measurement Committee. Results: Treatment with CPP-ACP caused a significant Delta E decrease with respect to the pre-stage (p smaller than 0.001), while the analysis of parameters that make up the colour showed a reduction in the difference of hue (Delta H) (p smaller than 0.001) and brightness (Delta L) (p smaller than 0.01) after applying CPP-ACP. Discussion: CPP-ACP penetrated to the depth of the white spot lesion, making its appearance similar to that of the sound enamel, probably because of the formation of different mineral phases than that of the original structure, although pores were not completely filled.
Resumen: la determinación objetiva del color se basa en el cálculo de la distancia colorimétrica (Delta E) dentro de un espacio cromático. Hasta el momento el más usado en odontología ha sido CIE L*a*b (Comission Internationale de l´Éclairage). Recientemente se ha desarrollado CIE L*C*h*, que tiene mayor correspondencia con la percepción del ojo humano. Objetivo: evaluar la capacidad de una sustancia remineralizante de mimetizar el color de la mancha blanca (MB) in vitro con el esmalte sano, determinando Delta E mediante el espacio cromático CIE L*C*h*. Método: se generó la MB in vitro sumergiendo 10 muestras obtenidas de terceros molares humanos en solución desmineralizante durante 72 h., luego se aplicó pasta con fosfato de calcio amorfo estabilizado por fosfopéptidos de caseína (CPP-ACP) durante 60 días manteniendo las muestras en saliva artificial a 37ºC. Para evaluar el color, se obtuvieron imágenes de las muestras ubicadas en moldes de silicona confeccionadas ad hoc luego de generar la MB (etapa pre) y del protocolo remineralizante (etapa post) mediante escáner y se aplicó la ecuación de Distancia colorimétrica según Color Measurement Committee. (Delta E*CMC). Resultados: el tratamiento con CPP-ACP provocó una disminución significativa de Delta E respecto de la etapa pre (p menor que 0,001) mientras que el análisis de los parámetros que componen el color mostró disminución en la diferencia del tono (Delta H) (p menor que 0,001) y la luminosidad ( Delta L ) (p menor que 0,01) luego de aplicar CPP-ACP. Discusión: CPP-ACP penetró a la profundidad de la lesión, acercando la apariencia de la MB a la del esmalte sano, probablemente por la formación de fases minerales distintas a las de la estructura original aun cuando lo poros no hayan sido completamente rellenados.
Subject(s)
Humans , Male , Female , Dental Caries/pathology , Dental Enamel/pathology , In Vitro Techniques , Tooth Demineralization , Tooth RemineralizationABSTRACT
One of the main clinical problems during chemotherapy is the occurrence of severe systemic toxicities, including those related to the stomatognathic system, which contribute to reducing the patient's quality of life. The most frequent oral complications are mucositis, dysgeusia, inflammation, gingival bleeding and decreased salivary flow or hyposalivation, a factor that predisposes to xerostomia, and other local complications that alter the homeostasis of the system. The purpose of this study was to evaluate the functional activity of salivary glands in Wistar rats subject to chemotherapy by measuring salivary flow, glycogen levels and glandular tissue response to autonomic nervous system agonists. Five experimental groups were used: 1) Control group fed "ad libitum"; 2) 5-fluorouracil (20mg/ kg body weight); 3) Calcium leucovorin (10 mg/kg body weight); 4) 5-fluorouracil + calcium leucovorin (20 and 10 mg / kg, respectively) by intraperitoneal injection for five consecutive days and 5) control with paired diet. Groups 1 and 5 did not receive drugs. Treatment with fluorouracil + leucovorin produced an increase in stimulated salivary flow and a higher response to increasing doses of beta agonists compared to other experimental groups. In both groups treated with cytostatic drugs, blocking of glycogen consumption at the end of the experimental period was observed. Our work suggests that salivary secretion may be affected by a dual mechanism: the first would be toxicity induced by 5-FU, which would cause depression of the process of glucose utilization. The second mechanism would affect the sympathetic autonomic reflex arc. In this instance, the synergistic action of 5-FU + LV would have a negative effect on the nerve activity with a reduction of salivary secretion. This would explain the hyposalivation, cited by several authors in patients undergoing the 5-FU+LV scheme in the treatment of colon carcinoma.
Uno de los principales problemas clinicos durante la quimioterapia es la aparicion de graves efectos toxicos sistemicos, incluidos los relacionados con el sistema estomatognatico, que contribuyen a la reduccion de la calidad de vida del paciente. Las complicaciones orales mas frecuentes son la mucositis, disgeusia, inflamacion, sangrado gingival y la disminucion del flujo salival o hiposalivacion, un factor que predispone a la xerostomia, y otras complicaciones locales que alteran la homeostasis del sistema. El objetivo de este estudio fue evaluar la actividad funcional de las glandulas salivales de ratas Wistar sometidas a quimioterapia, a traves de la medicion del flujo salival, los niveles de glucogeno y la respuesta del tejido glandular a agonistas del sistema nervioso autonomo. Se utilizaron cinco grupos experimentales: 1) Control con alimentacion "ad libitum"; 2) 5 - fluorouracilo (20 mg / kg de peso corporal); 3) Leucovorina calcica (10 mg/ kg de peso corporal); 4) 5 - fluorouracilo + leucovorina calcica (20 y 10 mg / kg, respectivamente) por via intraperitoneal durante cinco dias consecutivos, y 5) control con dieta apareada. Grupos 1 y 5 no recibieron drogas. El tratamiento con 5 - fluorouracilo + leucovorina produjo un aumento de flujo salival estimulado y una mayor respuesta a dosis crecientes de agonistas beta en comparacion con otros grupos experimentales. En ambos grupos tratados con citostaticos, se observo bloqueo del consumo de glucogeno al final del periodo. Nuestro trabajo sugiere que la secrecion salival puede estar afectada por un doble mecanismo: el primero seria la toxicidad inducida por 5-FU que causaria depresion del proceso de utilizacion de la glucosa. El segundo mecanismo afectaria el arco reflejo autonomo simpatico. En este caso, la accion sinergica de ambos farmacos de 5-FU + LV repercutiria negativamente sobre la actividad nerviosa con una reduccion de la secrecion salival. Esto explicaria la hiposalivacion citada por varios autores en pacientes sometidos al esquema 5-FU + LV en el tratamiento del carcinoma colorrectal.
Subject(s)
Animals , Male , Rats , Submandibular Gland/drug effects , Submandibular Gland/physiopathology , Leucovorin/pharmacology , Cytostatic Agents/pharmacology , Fluorouracil/pharmacology , Rats, WistarABSTRACT
En zonas del norte (ZN) y noroeste (ZNO) cordobés se estudió la prevalencia de fluorosis dental. En agua de consumo se determinó la concentración de Fluoruro (F-).En individuos de 5 a 14 años se evaluó la ingesta total diariade F-, concentración de F- en saliva y el índice de fluorosis dental. El agua presentó concentración de F- excesiva (ZN: 1,35 a 7,0 mg/l; ZNO: 1.7 a 3,4 mg/l). La ingesta diaria deF- duplicó la recomendada por la OMS (1,68 mg/día). El Fensaliva basal fue de 0,11 ± 0,03 mg/l (ZN) y 0,02 ± 0,001 mg/l (ZNO). La fluorosis dental en todas las superficies dentales permanentes fue del 75,6% (ZN) y 86.7% (ZNO)y en dientes maxilares anteriores del 87,7% (ZN) y 77,8% (ZNO). En el segundo molar primario fue del 22,2% (ZN) y 32,5% (ZNO). Se establece que ambas zonas son áreas de fluorosis endémica.
The prevalence of dental fluorosis was studied in northern(N) and northwestern (NW) areas of the province of Cordoba,Argentina. Fluoride (F-) concentration in drinking water wasdetermined. Daily total intake of F-, salivary F- concentrationand dental fluorosis index were evaluated in individuals from 5 to 14 years old. F- concentration in water was excessive (N: 1.35 to 7.0 mg/l; NW: 1.7to 3.4 mg/l). Daily intake of F- doubled the intake recommended by WHO (1.68 mg/day).