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Project

Exploring factors that influence and enhance probiotic survival in and colonization of the oral cavity.

The oral cavity harbors a complex microbial community containing up to 700 different genotypes .Some of these microbial communities develop on oral surfaces in structurally and functionally organized biofilms, also known as dental plaque. Dental plaque is a bacterial biofilm which is associated with tooth decay and periodontitis. Not all bacteria in dental plaque contribute to these diseases as they will only develop when specific pathogens become numerically dominant. Periodontitis, one of the most common diseases world-wide, is characterized by an overactive and destructive inflammatory response of the host to the dysbiotic biofilm community. Standard therapy focuses on reducing the bacterial threat by mechanical subgingival debridement and improving oral hygiene. This alters the subgingival microbiota to a less pathogenic composition. Although overall subgingival microbial reductions of up to 3 logs are easily achieved, recolonization, with less putative pathogens, to baseline levels occurs within 2 weeks. The efficacy of oral hygiene, subgingival debridement, and disease severity affect recolonization. This necessitates a life-long follow-up and sometimes re-treatment of periodontitis patients. Thus, periodontitis is a continuous health and socioeconomic threat. Despite clinical benefits, the use of antimicrobials and antibiotics to treat periodontitis is controversial. The emergence of antibiotic-resistant bacteria globally favors the development of non-antibiotic approaches. Oral bacteria can also develop tolerance to common antiseptics, which is linked to increased antibiotic resistance. Additionally, the a-specific eradication of oral bacteria with chlorhexidine-based antiseptic mouthwashes reduces nitrate to nitrite conversion and raises thereby blood pressure in normotensive subjects. Given the above, there is an urgent need to lower the global prevalence of periodontitis and the use of antibiotics and antiseptics in its prevention and treatment. To accomplish the latter, new therapies aim to maintain or restore the health-associated homeostasis of the oral microbiota and additionally modulate the host immune response at diseased sites. One emerging approach is the use of probiotics. In vitro, animal, and clinical research have shown the concept's validity and benefits in preventing and treating periodontitis and other oral diseases. However, the efficacy and widespread application of probiotics for oral health are hampered by a number of known and unknown issues that this PhD application seeks to investigate. These include: 1. It is unclear if, which and how the use of a toothpastes or mouthrinses can affect the survival, colonization and efficacy of probiotics for oral health 2. What is the impact of a biofilm on the colonization of probiotics for oral health. 3. It is unknown if the moment of use of a probiotic for oral health influences its survival and colonization within the oral cavity. 4. It is hypothesised that multi-species probiotic combinations are more effective than single species probiotic combinations. However there is no evidence for that for oral health probiotics. 5. It is unknown whether probiotics for oral health have disease-specific or patient-specific effects. This PhD aims to answer these basic but clinically extremely important questions and provide clinical guidelines for the use of probiotics for oral health through a series of in vitro, ex vivo, and clinical experiments.

Date:17 Feb 2023 →  Today
Keywords:Periodontitis, Oral health, Biofilm, Microbiology, Probiotics
Disciplines:Dentistry not elsewhere classified, Microbiology not elsewhere classified
Project type:PhD project