Dental biofilms

Carlen A, Rudiger SG, Loggner I, Olsson J Bacteria-binding plasma proteins in pellicles formed on hydroxyapatite in vitro and on teeth in vivo. Oral Microbiol Immunol 2003 18 203-207. Rudiger SG, Carlen A, Meurman JH, Kari K, Olsson J Dental biofilms at healthy and inflamed gingival margins. J Clin Periodont 2002 29 524-529. 

As noted earher (Sect. 12.1.3), the reduced enamel epithelium is replaced with adherent salivary proteins, mostly amylase and acidic proline-rich proteins. The acidic PRPs are at about a three times greater concentration than in secreted saliva. The acidic domain of these proteins especially has a high affinity for hydroxyapatite. Once bound to pelhcle, the N-terminus of acidic-PRPs forms an attachment site for the major classes of commensal bacteria (viridans streptococci and Actinomyces spp.) that occupy the mucosal surfaces and saliva of a healthy oral cavity. Some streptococci grow by themselves in dental biofilms, but many others grow better if certain Actinomyces spp. are also present. 

Bones and teeth dissolve in acid. The insoluble calcium monophosphate salt, from which hydroxyapatite is made, is converted to the more soluble calcium dihydrogen phosphate salt in an environment whose pH is less than 6.2 (Sect. 9.1.1). The severity of caries was related to the pH produced in dental biofilms (plaques) after ingesting sucrose and other sugars by Richard M Stephan. The pH response he identified is referred to as Stephan Curve. He found that the starting pH, the extent of its drop, and the time for recovery to the starting pH were all related to caries severity. The pH drop was later associated with lactic acid production due to bacterial carbohydrate fermentation (saccharolytic fermentation, Sect. 1.3.2). The subsequent rise in pH was due to the production of ammonia by bacterial... 

The permanence of bacterial plaque on the tooth surface will lead to loss of minerals constituents of the dental enamel, promoting the installation of the caries disease [42,43]. The carious lesion is characterized by the tooth structure (hydroxyapatite) di-mineralization by the production of organic acids, such as lactic acid, resulting from bacterial (dental biofilm) metabolism [42,43]. This results in loss of calcium and phosphate ions, which subsequently diffuse out of the tooth. In this complex process, the microorganism, particularly streptococcus species, have an important role in its etiology [43]. 

The application of tragacanth solution to hydroxyapatite in vitro and as a mouth wash to humans significantly reduced the adhesion and dental biofilm development of Streptococcus mutans to hydrxoyapatite and to teeth, respectively. ... 

An in vitro investigation into the bactericidal effects of a dental ultrasonic descaler on bacterial biofilms using Actinobacillus actinomycctcmcomitans and Porphyromonas gin-givalis has been reported [49]. Suspensions of the bacteria were subjected to the vibrations of a Cavitron PI insert for 2.5 and 5.0 min in an acoustically-simulated model substrate. A 60 % kill rate was achieved at a temperature of around 50 °C which constituted an alternative treatment for bacterial biofilms. This study suggested that a similar approach could be used in the clean-up of a range of biofQms considered to be the cause of a range of environmental hazards. 

Marquis RE (1995) Oxygen metabolism, oxidative stress and acid-base physiology of dental plaque biofilms. J Ind Microbiol 15, 198-207. 

The presence of S. mutans and other cariogenic bacteria contributes towards the formation of a biofilm known as dental plaque, and their metabolism of fermentable carbohydrates in the diet leads to the formation of acids [12]. Dental caries has been described as a complex imbalance in physiologic equilibrium between tooth mineral and biofilm [13]. Biofilms imply the involvement of microbiological species [14], but the key concept included within this definition is that the bacteria involved are native to the body, not a group of specific invasive bacteria causing infection [14]. 

A biological matrix of micro-organisms, their excretion products, and trapped particles. (N.B. dental plaque is a biofilm). 

Marsh, P. D. 1995. Dental plaque. In Microbial Biofilms (H. Lappin-Scott and J. W. Costerton, Eds.), Plant and Microbial Biotechnology Research Series 5, pp. 282-300. Cambridge Univ. Press, Cambridge, UK. 

Dental caries is a common chronic disease in which contact between teeth, food, and bacteria is involved. The major bacteria involved are believed to be Streptococcus mutans and S. sobrinus, although several Other types of bacteria are involved. Three stages have been outlined in caries adherence of bacteria to the teeth, formation of glycocalyx due to synthesis of a sticky glucan by the action of the bacterial enzyme glucosyl transferase on sucrose, and accumulation of plaque, which is a biofilm. In the dental plaque, there is continuing acid production by the bacteria, which are able to metabolize carbohydrates in acid medium, and the acid demineralizes the enamel of the teeth. 

Wong L, Sissons CH, Pearce EIF, Cutress TW Calcium phosphate deposition in human dental plaque microcosm biofilms induced by a ureolytic pH-rise procedure. Arch Oral Biol 2002 47 ... 

Listgarten MA Formation of dental plaque and other oral biofilms, in Newman HN, Wilson M (eds) Dental Plaque Revisited — Oral Biofilms in Health and Disease. Cardiff Bioline, 1999 187-210. 

Marsh PD, Bradshaw DJ Dental plaque as a biofilm. J Induct Micro 1995 15 169-175. 

Robinson C, Kirkham J, Percival R, Shore RC, Bonass WA, Brookes SJ, Kusa L, Nakagaki H, Kato K, Nattress B A method for the quantitative site-specific study of the biochemistry within dental plaque biofilms formed in vivo. Caries Res 1997 31 194-200. 

Teeth adherent bacterial biofilms, commonly called plaque or plaques, are responsible for the common forms of periodontal disease (Chap. 13) and dental caries (Chap. 15). In children or adults who keep their teeth clean and have no periodontal disease, the bacteria in a biofilm (the microbiota) is mostly gram positive and resembles that in saliva or adhering to the oral mucosa. The microbiota is predominantly saccharolytic and the major fermentation... 

The salivary proline-rich proteins have a two-domain structure, a proline poorN-terminal domain that is acidic or basic and determines enamel binding, and a proline-rich C-terminal domain that determines bacterial binding. Individual variations in acidic proline-rich proline allelic composition and in the amount of salivary agglutinin, a secreted innate immunity protein that binds bacteria, may account for differences in biofilm composition and dental caries susceptibility. 

The probiotic strain E. faecium PR88 was studied in clinical trial (Allen et al. 1996). The consumption of this strain led to alleviation of the symptoms of irritable bowel syndrome in humans. The efficacy and safety of live combmedBifidobacterium, Lactobacillus and Enterococcus capsules in treatment of irritable bowel syndrome was also demonstrated (Fan et al. 2006). E. faecium functions as a probiotic strain inhibiting biofilm formation by Streptococcus mutants, which is an etiological agent for dental caries (Kumada et al. 2008). 

Dental Water Line Biofilm Growth Data, Example 8.5... 

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