Toothbrush technology, dentifrices and dental biofilm removal

Dental plaque is a complex biofilm consisting of a polysaccharide matrix containing bacteria, voids and nonvital material of bacterial origin. Both cariogenic and periodontopathic bacteria reside in dental biofilm (plaque). While other factors must also be present for caries or periodontal disease to exist in a patient, without these bacteria neither bacterial disease will occur. The primary goal of toothbrushing is to remove the dental biofilm present on and adjacent to the teeth, thereby removing the bacteria associated with caries and periodontal disease; use of a dentifrice while brushing helps remove plaque and will also deliver agents to the tooth surface. Manual, powered and sonic brushes have all been shown to be effective and safe for the removal of plaque, when used appropriately. Selecting or recommending oral hygiene aids involves a number of considerations, including effectiveness, cleaning ability, ease of use and likely compliance. Introduction Since prehistoric times, man has devised a variety of methods to clean and whiten teeth. Some of the earliest devices used as “toothbrushes” were similar to some woodstick devices currently in use. It was not until the second half of the 20th century that first powered and later sonic toothbrushes were introduced. Modern toothpaste precursors were developed starting in the early 1800s.1 The development of toothbrushes and dentifrices accelerated in the latter half of the 20th century, in the search for products ideally suited to their purpose. Early efforts at tooth cleaning were focused on making teeth look cleaner and whiter and freshening breath. There was, however, no understanding of dental biofilm (plaque). One of the first people to try to understand the oral ecology was Willoughby Miller, who believed that periodontal disease was caused by microbes, and who also published an article identifying several acidogenic bacteria.2,3 Seminal research in the 1960s and 1970s by Loe4 and others definitively demonstrated the role of plaque as a bacterial ecology involved in the development of periodontal disease. Bacteria were also known to be associated with caries. By the 1980s, it was known that dental plaque consisted of a complex environment containing both periodontopathic and cariogenic bacteria. The main cariogenic bacteria contained in dental biofilm are Streptococcus mutans, with lactobacilli and minor bacteria also playing a role. The associations among, and proportions of, bacteria change over time as strains that are more virulent are introduced. Supragingival plaque contains more aerobic bacteria (e.g., Streptococcus mutans) and acts as a bacterial reservoir for subgingival plaque. Subgingival plaque contains a high proportion of anaerobic bacteria (periodontopathogens). Gram-negative anaerobic bacteria gradually increase in number and alter the nature of the biofilm. Socransky and Hafferjee discovered that dental biofilm is made up of specific groupings of bacteria consisting of five complexes of varying pathogenicity and virulence.5,6,7 Three periodontopathogens in the red complex of bacteria — T. forsythensis, P. gingivalis and T. denticola — are considered to be the most common bacteria associated with periodontal disease.8 In mature biofilm, the bacteria are enveloped by the biofilm structure, which consists mainly of a polysaccharide matrix containing voids as well as nonvital material of bacterial origin. It is important to note that periodontal disease will not result from the presence of a bacterial infection on its own, but involves local and systemic contributing factors and the host response.9 Reducing, removing or changing the biofilm is carried out to try to reduce the bacteria associated with caries and periodontal disease, to freshen the breath and for social acceptance. A plethora of products is available for these indications, including toothbrushes, dentifrices, rinses, creams, and professional and prescription products. Agents that have antibacterial properties include triclosan/copolymer, essential oils, chlorhexidine, xylitol and cetylpyridinium chloride. The scope of this article is to address plaque removal. Ideal Toothbrush and Dentifrice Properties Toothbrushes are designed for dental plaque removal in as efficacious a manner as possible, without damaging the hard or soft tissues, and dentifrice slurry provides some cleaning ability with a toothbrush. An ideal toothbrush should effectively and safely remove plaque and deliver agents in the dentifrice to the tooth surface. It should be easy to use, ergonomic and patient-friendly and be able to remove plaque from all surfaces of the tooth, including interstitially. For children, the toothbrush can incorporate design features that help motivate them to brush. An ideal dentifrice should help prevent plaque formation, disrupt plaque and optimize plaque removal. It should also contain agents that help protect the dentition and periodontal tissues; these include agents that prevent demineralization and aid remineralization; prevent and reduce periodontal inflammation and disease; help prevent oral ulcerations, irritations and other oral conditions; and prevent or reduce halitosis. In addition, the toothbrush and dentifrice should be effective