Oral biofilm models for mechanical plaque removal

Abstract

In vitro plaque removal studies require biofilm models that resemble in vivo dental plaque. Here, we compare contact and non-contact removal of single and dual-species biofilms as well as of biofilms grown from human whole saliva in vitro using different biofilm models. Bacteria were adhered to a salivary pellicle for 2 h or grown after adhesion for 16 h, after which, their removal was evaluated. In a contact mode, no differences were observed between the manual, rotating, or sonic brushing; and removal was on average 39%, 84%, and 95% for Streptococcus mutans, Streptococcus oralis, and Actinomyces naeslundii, respectively, and 90% and 54% for the dual- and multi-species biofilms, respectively. However, in a non-contact mode, rotating and sonic brushes still removed considerable numbers of bacteria (24–40%), while the manual brush as a control (5–11%) did not. Single A. naeslundii and dual-species (A. naeslundii and S. oralis) biofilms were more difficult to remove after 16 h growth than after 2 h adhesion (on average, 62% and 93% for 16- and 2-h-old biofilms, respectively), while in contrast, biofilms grown from whole saliva were easier to remove (97% after 16 h and 54% after 2 h of growth). Considering the strong adhesion of dual-species biofilms and their easier more reproducible growth compared with biofilms grown from whole saliva, dual-species biofilms of A. naeslundii and S. oralis are suggested to be preferred for use in mechanical plaque removal studies in vitro.

A randomized, controlled clinical trial on the clinical, microbiological, and staining effects of a novel 0.05% chlorhexidine/herbal extract and a 0.1% chlorhexidine mouthrinse adjunct to periodontal surgery

“…Thus, it appears that the surgical treatment with adjunct rinsing with CHX does not change subgingival bacterial presence as identified in the present study. This is consistent with the perception that it is almost impossible to eliminate a biofilm through mechanical means once the biofilm has been established (Falagas et al 2009, Souza et al 2009, Verkaik et al 2009). Genetic predisposition may, furthermore, control bacterial colonization patterns (Papapanou et al 2009).…”

Energy transfer, volumetric expansion, and removal of oral biofilms by non‐contact brushing

“…The biofilm formed by initial colonizers provides the link (12) between a substratum and more pathogenic, later colonizers (10, 11) and therewith serves the important role of anchoring an entire biofilm to a substratum surface. Initial colonizers indeed adhere more strongly than later colonizers to saliva‐coated surfaces (13), and dual‐strain biofilms formed by streptococci and actinomyces have been demonstrated to be most difficult to remove from saliva‐coated surfaces, while being easy and reproducible to grow (14). Consequently, a pair of initial, co‐adhering bacterial strains was chosen for this study.…”

Modelling mechanical and chemical treatment of biofilms with two phenotypic resistance mechanisms

“…Verkaik and colleagues () compared the effectiveness of contact and non‐contact brushing of different species in oral biofilms. In contact mode, like manual brushing, the removal was on average 39%, 84% and 95% for Streptococcus mutans , Streptococcus oralis and Actinomyces naeslundii single‐species biofilms respectively.…”