using a mouth gag for pulpitis assessment in mice

Erstellung eines Mausmodells für eine Pulpaentzündung unter Verwendung eines neuartigen Mundknebels 

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 im Rampenlicht: Verbesserung der Zahnpulpaforschung mit verbesserten Mausmodellen

Etablierung eines murinen Pulpa-Expositionsmodells mit einem neuartigen Mundknebel für die Pulpitisforschung

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.

Verwendung eines Mundknebels zur Beurteilung von Pulpitis bei Mäusen

Befestigen Sie zunächst eine betäubte Maus in Rückenlage auf einer Fixierungsplatte. Sichern Sie die Gliedmaßen mit Hautband. Komprimieren Sie die freien Enden eines präparierten Mundknebels mit dem Daumen und dem Zeigefinger.Fixiere die vorderen Schneidezähne der Maus in der trapezförmigen Rille zwischen den beiden Armen des Mundknebels. Stellen Sie sicher, dass der Arm mit dem Zungenspatel auf dem Unterkiefer platziert ist. Überprüfen Sie den ersten Backenzahn des Oberkiefers, um sicherzustellen, dass er frei von Karies, Traumata und Odontogenese ist.Beurteilen Sie die umgebende Gingiva, um sicherzustellen, dass keine Rötungen, Schwellungen oder Fisteln vorhanden sind. Überprüfen Sie dann die Gesundheit der gegenüberliegenden Zähne. Bohren Sie anschließend mit einem Zahnfräser die okklusale Seite des ersten Molaren des Oberkiefers bei 20.000 U/min.Entferne den Zahnschmelz. Mit einer Spritze alle drei Minuten normale Kochsalzlösung über den Zahn tropfen, um eine Überhitzung zu vermeiden. Setzen Sie eine C+-Feile mit der Nummer 8 auf die unterste Position der Bohrgrube und stechen Sie das letzte Dentin ein, um die Pulpakammer freizulegen.Reinigen Sie die Fragmente um den Zahn herum und entfernen Sie dann den Mundknebel. Die Zeit, die benötigt wurde, um den Mund mit dem Mundknebel zu fixieren und den ersten Backenzahn des Oberkiefers zu finden, wurde im Vergleich zur traditionellen Methode deutlich verkürzt. Die Pulpafreilegung wurde durch Mikro-CT und Rekonstruktionsmodellierung bestätigt.24 Stunden nach der Operation behielt der größte Teil des Pulpagewebes seine Morphologie bei.

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 ...

Forschung

Medizin

Preparation of the Mouth Gag for a Mouse Pulpitis Model

Vorbereitung des Mundknebels für ein Pulpitis-Modell der Maus