Host response modulation in periodontics

Host response modulation (or host modulation) is a term that has been introduced to the dental profession relatively recently. In the periodontal context, and in very simple terms, it means modifying or modulating destructive or damaging aspects of the inflammatory host response that develops in the periodontal tissues as a result of the chronic challenge presented by the subgingival bacterial plaque. Host response modulation is routinely practised by our medical colleagues, who use host modulation strategies in the treatment of disorders such as rheumatoid arthritis and osteoporosis. And while the term host modulation has only recently started to be widely used in general dentistry, the concept was first introduced to the research community in the late 1980s and early 1990s (34, 107). Indeed, in 1990 Williams (107) stated that ‘there are compelling data from studies in animals and human trials indicating that pharmacologic agents that modulate the host responses believed to be involved in the pathogenesis of periodontal destruction may be efficacious in slowing the progression of disease’. Over the last two decades, a variety of pharmacological agents have been studied for a possible role as host modulators in the management of periodontal disease. These include nonsteroidal anti-inflammatory drugs, bisphosphonates and the tetracycline family of compounds (and their chemically modified analogues). Newer agents that have the potential to be of benefit in periodontal treatment include anti-cytokine drugs (which have successfully been used in the treatment of rheumatoid arthritis), soluble cytokine blockers and lipoxins. To date, only one systemic medication has been licensed specifically as a host response modulator for the treatment of periodontal disease, and that is subantimicrobial dose doxycycline (a focus in this review). The inclusion of host response modulation into periodontal management strategies is an exciting development with significant potential for improving treatment outcomes. It is likely that the future will see a range of host modulation therapies developed that target different aspects of the inflammatory pathogenic processes which occur in the diseased periodontium