Review on the Lymphatic Vessels in the Dental Pulp

Abstract

Despite many studies, opinions on the lymphatic system of the teeth are still incompatible. Studies using light and electron microscopy and directly using methods such as a radioisotope (radionuclide) scan and interstitial fluid pressure measurement reported incomplete results. Immunohistochemistry (IHC) plays the main role in investigating presence of the lymphatic system in dental tissues. This method uses labeled antibodies against antigens typical of lymphatic vessels. The use of appropriate staining enables the detection of antigen-antibody reaction products using a light (optical), electron or fluorescence microscope. However, these studies do not show the system of vessels, their histologic structure under physiological conditions and inflammation as well as the lymphangiogenesis process in the dental pulp. Unfortunately, there is a lack of studies associating the presence of lymphatic vessels in the dental pulp with local lymphatic nodes or large vessels outside the tooth. In the scientific and research environment, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels. Despite many indications of the presence of lymphatic vessels in the pulp chamber, this problem remains open and needs further research.

Insights Into Pulp Biomineralization in Human Teeth

“…Higher mineral densities but lower fracture resistance of dentin with age (27-30), decreased dentin permeability resulting from microbial attack (14,31), and increased loss in tooth-sensitivity with increased cuspal attrition (5,14) all are adapted characteristics of dentin. The white-reflecting and dark-opaque features in dentin encircling root canals in Figure 1 indicated that, dentin indeed has adapted to conditions other than normal (1,5,12,14,(31)(32)(33)(34)(35).…”

“…The tissues of teeth are routinely subjected to insults in multiple ways. Acute and chronic tissue responses to insults (mechanical, chemical, and/or microbial loads) (1,5,12,14) are often registered as spatial (macroscale DPC, microscale tissue/matrix/cell, and nanoscale particulate/biomoelcular levels) and temporal (short and long-term that can be connected to acute and chronic inflammatory cascades) adaptations. These adaptations are often mapped as changes in physicochemical, and biochemical characteristics using multiple high resolution microscopy and spectroscopy techniques.…”

“…Biominerals within pulp to date have undergone rudimentary investigations, despite being identified and categorized as free or embedded in pulp, and/or attached to dentin (11). Mineralization of the innervated and vascularized pulp can result from sterile or non-sterile inflammation (12), and from pathways similar to those reported in neurovascular skeletal and smooth muscles (13). The primary effectors that inextricably shift the IFP of the vascularized and innervated pressurized pulp include molecular-and tissue-level factors that occur locally at site-specific anatomical locations.…”

“…This net increase in IFP invariably "tips" the homeostatic balance and triggers acute or chronic inflammatory pathway(s). The impact of the inflammatory pathways on the pulp also depends on the magnitude, frequency and duration of the insult, and masticatory function (1,5,12,14). Conceivably, this naturally engineered pressure chamber is mechanically stressed and strained, and contains pressure and chemical graidents.…”

Dynamics of Innate Immune Response Due to Bacteria-Induced Pulpitis

“…Our flow cytometry analysis showed that on day seven after injury, there was continuity of acute inflammation and predominately innate immune responses with little evidence for a transition to adaptive immune responses and chronic inflammation. There is also discussion on whether human dental pulp tissue has its lymphatic system and how it functions (Bernick 1977; Gerli et al 2010; Wisniewska et al 2021), raising questions about how the adaptive immune response might be also different in the pulp tissue compared other tissues. We did find that there was an increase in T cell population on day 7.…”