LAUSR

Challenges for oral biofilm control & dental caries prevention According to epidemiological data from the WHO, 60–90% of school children and the majority of adults have dental caries (‘toothdecay’) worldwide, often causing pain and discomfort that can lead to absenteeism from school and work. Furthermore, the prevalence of untreated caries remains high, affecting 35% of the global population [1]. The annual cost of treatment for this prevalent disease exceeds $120 billion in the USA alone [1]. Prevention or treatment of dental caries remains challenging with high recurrence despite significant advances due to the widespread use of fluoride. One major problem is the complex etiology and pathogenesis of the disease (involving diet, host and microbial interactions) that lead to the development of highly virulent and adherent biofilms on teeth that are difficult to control or remove once is established. Caries-causing (cariogenic) biofilm develops as oral microbes accumulate on tooth surface, forming structured communities enmeshed in an extracellular matrix comprised of polymeric substances such as exopolysaccharides (EPS) [2]. The matrix creates spatial and microenvironmental heterogeneity in biofilms, modulating the growth and protection of pathogens against antimicrobials locally. Within the complex oral micro biome, pathogens such as Streptococcus mutans are not always the most abundant organism. However, it can rapidly orchestrate the formation of cariogenic biofilms on pellicle-coated teeth when frequently exposed to sugars (e.g., sucrose), a dietary hallmark of caries-prone population. Sucrose can be utilized to produce EPS on the pellicle and on bacterial surfaces. EPS formed in situ promote local accumulation of microbes on teeth while forming a spatially heterogeneous and diffusion-limiting matrix. In parallel, sugars are fermented by bacteria embedded in the matrix, creating highly acidic microenvironments [2,3]. The low pH niches promote EPS production and biofilm accretion where cariogenic flora (acid-tolerant and acidogenic) prosper. Consequently, the persistent local acidity ensures acid-dissolution of adjacent tooth enamel, leading to the onset of dental caries [4]. Importantly, local bacterial clusters, delineated by the matrix, become recalcitrant to antimicrobials, making biofilm elimination difficult. Therefore, preventing or treating cariogenic oral biofilms is challenging threefold: protection provided by the EPS-rich matrix; the creation of highly acidic and compartmentalized micro environments; poor retention of topically applied agents (e.g., mouthrinses) due to rapid clearance in the mouth. To address these remarkable hurdles, an effective antibiofilm strategy should breakdown the protective matrix to enhance localized bacterial killing under the acidic microenvironment via facile topical treatment. Furthermore, precise targeting of Do catalytic nanoparticles offer an improved therapeutic strategy to combat dental biofilms?