Fluid transport from the dental pulp revisited

Area of Science:

• Oral Biology
• Physiology
• Anatomy

Background:

• Dental pulp fluid pressure increases rapidly due to rigid dentinal walls.
• A fluid drainage system is essential for maintaining pressure homeostasis in the dental pulp.
• The dental pulp and apical periodontal ligament lack conventional lymphatic vessels, posing questions about fluid transport mechanisms.

Purpose of the Study:

• To investigate the mechanisms of fluid transport within the dental pulp.
• To identify the location of lymphatic vessels draining the apical periodontal ligament.
• To understand the implications of aging and conditions like acute apical periodontitis on dental pulp fluid dynamics.

Main Methods:

• The study proposes a model based on tissue pressure gradients driving fluid transport.
• Fluid is suggested to move through loose connective tissue spaces surrounding neurovascular bundles.
• Lymphatic vessels are identified within bone channels of the periapical ligament and mandibular canal.

Main Results:

• Fluid drainage within the pulp is likely governed by tissue pressure gradients and occurs in interstitial spaces.
• Aging-induced fibrosis in dental pulp reduces fluid drainage capacity, potentially leading to circulatory failure.
• Lymphatic vessels are located in the periapical ligament and mandibular canal, with slow washout rates that may be influenced by chewing.
• Inflammatory mediators and bacterial products can spread to lymph nodes via these lymphatic vessels during acute apical periodontitis.

Conclusions:

• Fluid transport in the dental pulp occurs via interstitial spaces driven by pressure gradients.
• Reduced drainage capacity due to aging compromises pulp health and increases susceptibility to damage.
• Lymphatic vessels in the jaw bone play a crucial role in draining periapical tissues and can facilitate pathogen spread during infection.