To Örebro University

Periodontitis is an inflammatory condition affecting tooth-supportive structures, the periodontium. Gingival tissues respond to biofilm formation by initiating an inflammatory process. If left untreated, inflammation progresses to a non-reversible condition in susceptible individuals, causing degradation of the underlying bone structures, where teeth become mobile and tooth-loss eventually occurs. Periodontitis is very common, affecting about half of the adult population. The disease is not only a concern for oral health but is linked to many systemic conditions, such as cardiovascular disease, diabetes, rheumatoid arthritis, and Alzheimer’s.

The studies included in this thesis aim to develop new strategies for the diagnosis and treatment of periodontal disease. Current diagnostic practices rely on probing and x-ray examination. There is a need for more sophisticated diagnostic tools. We have developed different sensing strategies for detection of a key-pathogen in periodontitis, Porphyromonas gingivalis, and its secreted enzymes, gingipains. The proteolytic activity of this pathogen, which drives the destructive effects of the disease, can be detected at low levels by utilizing gold nanoparticles and nanoplasmonic sensing in different ways.

Treatment of periodontitis is basically limited to the removal of soft and hard biofilms. This requires significant resources, from patients as well as clinicians, and maintenance phase is often life-long. We have identified and tested the antibacterial effect of an antimicrobial peptide derived from Lactobacillus plantarum. This bacteriocin, plantaricin NC8αβ, has been shown to effectively inhibit P. gingivalis. The bacteriocin has been further optimized into a short peptide sequence, C5, which can rupture outer membrane vesicles from P. gingivalis. Taken together, these results suggest new sensing strategies for novel diagnostic tools for periodontal disease and define a promising antibacterial agent for periodontal treatment in the future.