using a mouth gag for pulpitis assessment in mice

Criando um modelo de camundongo de inflamação pulpar usando uma nova mordaça na boca 

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 em destaque: aprimorando a pesquisa da polpa dentária com modelos de camundongos aprimorados

Estabelecimento de um modelo de exposição à polpa murina com uma nova mordaça bucal para pesquisa de pulpite

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.

Usando uma mordaça bucal para avaliação de pulpite em camundongos

Para começar, fixe um camundongo anestesiado em decúbito dorsal em uma placa de fixação. Prenda os membros com fita adesiva. Comprima as pontas livres de uma mordaça bucal preparada com o polegar e o indicador.Fixe os incisivos frontais do mouse na ranhura trapezoidal entre os dois braços da mordaça bucal. Certifique-se de que o braço com o abaixador de língua esteja colocado na mandíbula. Verifique o primeiro molar superior para garantir que esteja livre de cáries dentárias, traumas e odontogênese.Avalie a gengiva circundante para garantir a ausência de vermelhidão, inchaço ou fístula. Em seguida, verifique a saúde dos dentes opostos. Em seguida, com uma broca dentária, perfure o lado oclusal do primeiro molar superior a 20.000 RPM.Remova o esmalte. Com uma seringa, coloque soro fisiológico a cada três minutos sobre o dente para evitar o superaquecimento. Coloque uma lima C+ número 8 na posição mais baixa do poço perfurado e perfure a última dentina para expor a câmara pulpar.Limpe os fragmentos ao redor do dente e, em seguida, remova a mordaça bucal. O tempo necessário para fixar a boca com a mordaça bucal e encontrar o primeiro molar superior foi significativamente reduzido em relação ao método tradicional. A exposição pulpar foi confirmada por meio de micro CT e modelagem de reconstrução.Às 24 horas de pós-operatório, a maior parte do tecido pulpar manteve sua morfologia.

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 ...

Medicina

Preparation of the Mouth Gag for a Mouse Pulpitis Model

Preparação da mordaça bucal para um modelo de pulpite de camundongo