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Extracellular fluid movement in the pulp; the pulp/dentin permeability barrier
1Department of Basic Sciences, Northwestern University, Chicago.
Proceedings of the Finnish Dental Society. Suomen Hammaslaakariseuran Toimituksia
|January 1, 1992
Summary
Pulp fluid does not normally enter predentin due to a barrier at the odontoblast layer. This barrier maintains a controlled environment for dentin formation and may influence inflammatory conditions.
Area of Science:
- Oral Biology
- Dentinogenesis
- Pulp Physiology
Background:
- Pulp fluid movement is crucial for tooth health and depends on blood vessel physiology.
- Normally, fluid and proteins move from capillaries into the extracellular pulp space.
- Pulp capillaries are located near the odontoblast layer, suggesting a potential pathway for fluid movement into predentin.
Purpose of the Study:
- To investigate if fluid can pass between odontoblasts into the predentin.
- To examine the permeability barrier at the apical end of odontoblasts.
- To understand the implications of this barrier for dentin formation and pulpal inflammation.
Main Methods:
- Perfusing molar tooth germ vessels in piglets with the tracer lanthanum.
- Utilizing electron microscopy to observe tracer distribution.
- Examining structural evidence of tight junctions and collagen fibers between odontoblasts.
Main Results:
- The tracer lanthanum permeated capillaries but was blocked at the apical ends of odontoblasts.
- Tight junctions between odontoblasts, present in both pigs and humans, contribute to this barrier.
- Collagen fibers were observed within the tight junctional zone.
Conclusions:
- There is minimal to no evidence of normal pulp fluid confluence with predentin.
- The odontoblast barrier creates a controlled microenvironment essential for matrix deposition and mineralization.
- Understanding intrapulpal fluid dynamics, including lymphatic drainage, may explain variations in pulpal inflammatory conditions.