using a mouth gag for pulpitis assessment in mice

Creación de un modelo de ratón de inflamación de la pulpa utilizando una novedosa mordaza bucal 

The dental pulp, an integral part of the tooth, is responsible for multiple essential functions such as nutrient supply, dentin formation, sensory function, and defense reactions1. Nevertheless, the dental pulp, surrounded by hard tissue, is susceptible to injuries and damages from deep caries, pulpitis, trauma, or subsequent therapies2,3. The absence of functional dental pulp increases the risk of tooth fragility4. Moreover, the loss of pulp vitality in young permanent teeth can adversely affect tooth maturation, and current denture techniques fail to restore the neural feedback offered by healthy pulp4. This situation has led researchers to explore alternative solutions for managing inflamed pulp beyond mere removal.
In 2007, Murray et al. initiated the application of tissue engineering in regenerative endodontics, thereby sparking increased interest in pulp preservation and regeneration5. However, inflamed pulp tissue poses a challenge as cells release inflammatory factors such as IL-6, which recruit inflammatory cells and results in cell necrosis, loss of pulp vitality, and complications in functional recovery6,7. Understanding inflammation and the associated cell death is, therefore, crucial for advancements in the preservation of vital pulp. There are a number of experiments that have been conducted to explore the molecular biology of the inflame pulp in vivo or in vitro8,9. Though in vitro&#160;experiments like 2D or 3D cell cultures have been developed for years and are becoming mature and widely used to test reactions of pulp cells to inflammatory factors, these experiments cannot reflect the interaction between pulp tissue and the systemic immune system10. If the phenomenon being studied is derived from cells of other tissue origin like immune, vascular and nervous system, then pure pulp cell culture will lead to a dead end. Therefore, in vivo experiments are very necessary and referential.
Mice have increasingly become a common choice in inflammation research in vivo&#160;due to their cost-effectiveness, high fertility, and vitality. However, a comprehensive protocol for mice pulpitis model is currently absent, which can serve as a reference. The small size of mice and their sensitivity to stimulation pose significant challenges during experimental procedures. Observing the minuscule teeth concealed deep within the mouse mouth often necessitates the use of a cantilever microscope, notwithstanding the more common presence of desktop microscopes in laboratories. The absence of a mouth opener requires assistance from others. To address this, the group has devised a mouth-gag using readily available materials which aims to provide a standardized and reproducible protocol for constructing the mice pulpitis model. This article details the procedure, covering preoperative preparation, immobilization, pulp exposure surgery, and sample collection on C57 mice. This protocol recommends the use of the mouth-gag, providing information on its structure, production, and application to facilitate other researchers in replicating the procedure.

Autor destacado: Mejora de la investigación de la pulpa dental con modelos de ratón mejorados

Establecimiento de un modelo de exposición a la pulpa murina con una mordaza bucal novedosa para la investigación de la pulpitis

Individual experiments like 2D or 3D cell cultures have been widely used to test the reactions of dental pulp cells. These experiments cannot reflect the interaction between pulp tissue and the systemic immune system. Therefore, in vivo experiments are becoming increasingly popular in endodontic research.C57 mice have increasingly become a common choice in inflammation research on dental pulp due to their cost effectiveness, high fertility and vitality. However, the small size of mice and lack of coordination posed significant challenges during experimental procedures. The fixation process is an important factor that higher the technical threshold.We devised a novel mouth gag using readily available materials and simple assemblies to assist researchers in pulp exposure surgery. According to our research, this mouth gag can significantly shorten the time required for beginners to immobilize the mouth and expose the maxillary first molar of mice.

Uso de una mordaza bucal para la evaluación de la pulpitis en ratones

Para comenzar, fije un ratón anestesiado en posición supina sobre una placa de fijación. Asegure las extremidades con cinta adhesiva para la piel. Comprima los extremos libres de una mordaza bucal preparada con el pulgar y el dedo índice.Fije los incisivos frontales del ratón en el surco trapezoidal entre los dos brazos de la mordaza bucal. Asegúrese de que el brazo con el depresor de lengua esté colocado sobre la mandíbula. Revise el primer molar maxilar para asegurarse de que esté libre de caries dental, traumatismos y odontogénesis.Evalúe la encía circundante para asegurarse de que no haya enrojecimiento, hinchazón o fístula. A continuación, comprueba la salud de los dientes opuestos. A continuación, con una fresa dental, perfore el lado oclusal del primer molar maxilar a 20.000 RPM.Retira el esmalte. Con una jeringa, deje caer solución salina normal cada tres minutos sobre el diente para evitar el sobrecalentamiento. Coloque una lima número 8 C + en la posición más baja del pozo perforado y perfore la última dentina para exponer la cámara pulpar.Limpie los fragmentos alrededor del diente y luego retire la mordaza bucal. El tiempo necesario para fijar la boca con la mordaza bucal y encontrar el primer molar maxilar se acortó significativamente en relación con el método tradicional. La exposición pulpar se confirmó mediante micro TC y modelos de reconstrucción.A las 24 horas después de la cirugía, la mayor parte del tejido pulpar conservó su morfología.

Research

JoVE Journal

Medicine

Using A Mouth Gag for Pulpitis Assessment in Mice

Establishment of a Murine Pulp Exposure Model with a Novel Mouth-Gag for Pulpitis Research

Pulpitis, a common cause of natural tooth loss, leads to necrosis and loss of bioactivity in the inflamed dental pulp. Unraveling the mechanisms ...

Investigación

Medicina

Preparation of the Mouth Gag for a Mouse Pulpitis Model

Preparación de la mordaza bucal para un modelo de pulpitis de ratón