Immune Defense Mechanisms of the Dental Pulp

Abstract

Defense reactions of the dentin/pulp complex involve a variety of biological systems, in which the immune system plays a pivotal role. The knowledge of the organization and function of pulpal immunocompetent cells has been sparse, but in recent years a significant body of information of immune mechanisms in general has provided a footing for substantial new knowledge of the immune mechanisms of the dental pulp. The identification of pulpal dendritic cells (DCs) has generated research activities which have led to a concept of how an antigenic challenge may evoke a pulpal inflammatory response. Although DCs are not able to identify foreign antigens specifically, they provide necessary signals to activate T-lymphocytes which in turn will orchestrate other immunocompetent cells to mount the local immune defense of the dental pulp. The purpose of this review is to accent the organization and function of pulpal DCs and other tissue and cellular components and to provide a basis for how they may interact to instigate pulpal defense mechanisms.

Lipoteichoic Acid Increases TLR and Functional Chemokine Expression while Reducing Dentin Formation in In Vitro Differentiated Human Odontoblasts

“…When the enamel barrier is disrupted, the dentin exposed to the oral environment is degraded by Gram-positive bacteria, including streptococci, lactobacilli, and actinomyces, that largely dominate the carious lesion microflora (2). This leads to the development of inflammatory and immune events in the dental pulp, the molecular and cellular determinants of which remain unknown (3).…”

“…They send long cytoplasmic processes into dentinal tissue. Thus, during dentin demineralization, bacteria and/or components released from their wall such as lipoteichoic acid (LTA) 2 (5,6) can gain access to odontoblasts (3). Therefore, they are the first cells encountered by bacteria entering dentin from the oral cavity.…”

“…This includes the secretion of proinflammatory chemokines and cytokines that recruit and activate blood borne inflammatory cells (10,11). In the dental pulp, when dentin is being destroyed by caries, immature dendritic cells (iDCss) accumulate into the odontoblast layer close to the lesion in strategic location to sample foreign Ags (3,12). Factors favoring this accumulation are unknown, but chemokines may be involved (13).…”

Tissue inflammatory response to implantation of calcium hydroxide and iodoform in the back of rats

“…Due to the presence of microorganisms and their by-products (1,2), the root canal system infection produces a host response, which may clinically show the presence and development of periapical lesions (3,4). These microorganisms are a constant source of aggression and demand an inflammatory response (5).…”

Evaluation of the responses of MHC class II molecule-expressing cells and macrophages to epoxy resin-based and 4-META-containing, methacrylate resin-based root canal sealers in rat subcutaneous tissue

“…Our recent in vivo study also showed that MetaSEAL induced a milder neutrophil infiltration in rat subcutaneous tissue than a zinc oxide-eugenol sealer 8) . Major histocompatibility complex (MHC) class II molecule-expressing cells serve as antigen-presenting 26) . Therefore, the response of MHC class II molecule-expressing cells is a good indicator of a biomaterial's immunogenic potential 8) .…”