Dental Pulp Response to Bacterial Cell Wall Material

Abstract

Lipopolysaccharides (LPS) from Bacteroides oralis and Veillonella parvula and cell wall material from Lactobacillus casei were studied for their capacity to induce leukocyte migration in the dental pulp and in an implanted wound chamber. Three adult monkeys were challenged using lyophilized material sealed into buccal Class V cavities prepared in dentin. Pulp tissue responses were observed histologically eight and 72 hours after initiation of the experiment. Subjacent to cut dentinal tubules, bacterial materials induced polymorphonuclear leukocyte (PMN's) infiltration in the pulp tissue of the majority of test teeth examined. Responses were similar for the three bacterial test materials at both time periods. Topical applications of bovine serum albumin (BSA), used as a control, induced significantly less accumulation of PMN's. Assessments of induced exudate volumes and leukocyte densities in chambers implanted in rats showed comparable rankings with pulpal experiment between test (i.e., bacterial) and control (BSA) materials. Analysis of the data indicates that high-molecular-weight complexes of bacterial cell walls may adversely affect pulpal tissue across freshly exposed dentin.

Relationships between Caries Bacteria, Host Responses, and Clinical Signs and Symptoms of Pulpitis

“…Based on experimental pulpitis studies, C3a and C5a generated from complement activation were thought to be important virulence factors of cariogenic bacteria that elicit neutrophil accumulation in the Arthus reaction (2,3,5,30). Recent studies, however, showed that the presence of an intact complement cascade is neither necessary nor sufficient to trigger or propagate the Arthus reaction (136,137).…”

“…Although bacteria or their cell-wall components such as LPS are capable of passing through tubules to induce inflammatory responses in the dental pulp (2,4,5,30), the thickness of dentin can greatly reduce the concentration of bacterial proteins and the amount of LPS that reaches the pulp (31,148,149). We infiltrated commercial LTA preparations from S. mutans through dentinal blocks using fluid filtration and observed that the dentin permeability decreased with time (Fig.…”

Immunocompetent Cells in the Normal Dental Pulp

“…The mechanisms involved in the initiation and monitoring of the pulp inflammatory defense are, however, not well understood. Experimental data have shown that antigens from oral micro-organisms induce inflammatory reactions in the pulp tissue across exposed dentin (Bergenholtz and Lindhe, 1975;Bergenholtz, 1977;Warfvinge et al, 1985), but the basis for the initial recognition of antigens and how they are processed in the pulp has not been clearly demonstrated.…”

Lipopolysaccharide Enhances Decorin Expression through the Toll-like Receptor 4, Myeloid Differentiating Factor 88, Nuclear Factor-Kappa B, and Mitogen-activated Protein Kinase Pathways in Odontoblast Cells

“…When deep caries are present, some odontoblasts may survive and participate in pulpal responses by forming new dentin (24,25). However, there are few reports on the effect of LPS on dentin matrix protein expression.…”