The stratified epithelia of the oral cavity are continually exposed to bacterial challenge that is initially resisted by innate epithelial factors and by the recruitment of neutrophils. Antimicrobial peptides from phagocytes and epithelia contribute to this antimicrobial barrier. Using antibodies and in situ hybridization, we explored antimicrobial peptide expression in the varied epithelia of the periodontium and in cultured gingival epithelial cells. In gingival tissue, mRNA for the beta-defensins, human beta-defensin 1 (hBD-1) and human beta-defensin 2 (hBD-2) was predominately localized in suprabasal stratified epithelium and the peptides were detected in upper epithelial layers consistent with the formation of the stratified epithelial barrier. In cultured epithelial cells, both hBD-1 and -2 peptides were detected only in differentiating, involucrin-positive epithelial cells, although hBD-2 required stimulation by proinflammatory mediators or bacterial products for expression. Beta-defensins were not detected in junctional epithelium (JE) that serves as the attachment to the tooth surface. In contrast, alpha-defensins and cathelicidin family member LL-37 were detected in polymorphonuclear neutrophils (PMNs) that migrate through the JE, a localization that persists during inflammation, when the JE and surrounding tissue are highly infiltrated with PMNs. Thus, the undifferentiated JE contains exogenously expressed alpha-defensins and LL-37, and the stratified epithelium contains endogenously expressed beta-defensins. These findings show that defensins and other antimicrobial peptides are localized in specific sites in the gingiva, are synthesized in different cell types, and are likely to serve different roles in various regions of the periodontium.

Chronic inflammation induced by bacteria often leads to host-mediated destruction of tissues adjacent to the sites of microbial insult. The chronic inflammatory process of adult periodontitis results in the destruction of supporting osseous and connective tissues of the teeth. We hypothesized that virulence factors of periodontal pathogens such as lipopolysaccharide stimulate inflammatory cytokine expression by mononuclear cells of the host which contribute to disease development. In this study, to elucidate the role of these cytokines in chronic adult periodontitis, we tested whether the prevalence of mRNA for inflammatory cytokines generally associated with mononuclear phagocytes was higher in diseased than in healthy gingival tissue. Gingival mononuclear cells or whole gingival biopsies from 32 adult periodontitis patients and five healthy individuals used as controls were evaluated for inflammatory cytokine mRNA expression by reverse-transcription polymerase chain-reaction (RT-PCR) procedures. The cytokines assessed included IL-1 alpha, IL-1 beta, IL-1ra, IL-6, IL-8, IL-12, IL-13, TNF-alpha, TGF-beta, and IFN-gamma. The monocyte/macrophage lipopolysaccharide (LPS) receptor CD14 was also assessed. Results showed that TNF-alpha mRNA was present significantly more frequently in diseased than in healthy biopsies, whereas IL-1 alpha, IL-1 beta, and IL-1ra mRNA were found in most (from 80 to 100%) healthy tissues. Message for CD14 was present in both healthy and diseased tissue samples (100%). This study provides evidence for a major role of TNF-alpha in chronic adult periodontitis. Moreover, our results suggest that the mononuclear cells derived from periodontal tissues have the capacity to respond to components of periodontal pathogens and express both pro- and anti-inflammatory cytokines in these tissues.

This review discusses polymicrobial interactions with the host in both health and disease. As our ability improves to identify specific bacterial clonal types both with respect to abundance and location in the oral biofilm we will learn more concerning their contribution to both oral health and disease. Recent studies examining host-bacterial interactions have revealed that commensal bacteria not only protect the host simply by niche occupation, but that bacterial interactions with host tissue can promote the development of proper tissue structure and function. These data indicate that our host-associated polymicrobial communities, such as those found in the oral cavity, co-evolved with us and have become an integral part of who we are. Understanding the microbial community factors that underpin associations with host tissue that contribute to periodontal health may also reveal how dysbiotic periodontopathic oral communities disrupt normal periodontal tissue functions in disease. A disruption of the oral microbial community creates dysbiosis, either by overgrowth of specific or nonspecific microorganisms or changes in the local host response where the community can now support a disease state. Dysbiosis provides the link between systemic changes (e.g., diabetes), exogenous risk factors (e.g., smoking), and the dysbiotic community and can drive the periodontal tissue destruction. Many other risk factors associated with periodontal disease such as stress, aging, and genetics also likely affect the microbial community, and more research is needed utilizing sophisticated bacterial taxonomic techniques to better elucidate these effects on the microbiome and to develop strategies to target the dysbiotic mechanisms and improve periodontal health.

Intrapocket administration of lidocaine 25 mg/g plus prilocaine 25 mg/g and thermosetting agents may be effective for pain control for scaling and root planing and may offer an alternative to infiltration anesthesia.

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