Microbial colonisation of human tooth surfaces
Royal Dental College, Faculty of Health Sciences, University of Aarhus, Denmark. APMIS. Supplementum
Available from: Egija Zaura
- "Although volunteers were asked to brush their teeth 12 hr before the samples were collected, the use of interdental oral hygiene means such as floss or toothpicks was not controlled. It is likely that older and thus more diverse plaque  was sampled at these sites. Higher diversity of the plaque from the lingual surface of the front tooth but not that of the molar tooth suggests that the composition of plaque of the lingual surface of the front tooth might be influenced by the anatomy of this surface - a protruding rounded tubercle at the gingival third of the crown, near the gingival sulcus. "
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ABSTRACT: Most studies examining the commensal human oral microbiome are focused on disease or are limited in methodology. In order to diagnose and treat diseases at an early and reversible stage an in-depth definition of health is indispensible. The aim of this study therefore was to define the healthy oral microbiome using recent advances in sequencing technology (454 pyrosequencing).
We sampled and sequenced microbiomes from several intraoral niches (dental surfaces, cheek, hard palate, tongue and saliva) in three healthy individuals. Within an individual oral cavity, we found over 3600 unique sequences, over 500 different OTUs or "species-level" phylotypes (sequences that clustered at 3% genetic difference) and 88 - 104 higher taxa (genus or more inclusive taxon). The predominant taxa belonged to Firmicutes (genus Streptococcus, family Veillonellaceae, genus Granulicatella), Proteobacteria (genus Neisseria, Haemophilus), Actinobacteria (genus Corynebacterium, Rothia, Actinomyces), Bacteroidetes (genus Prevotella, Capnocytophaga, Porphyromonas) and Fusobacteria (genus Fusobacterium).Each individual sample harboured on average 266 "species-level" phylotypes (SD 67; range 123 - 326) with cheek samples being the least diverse and the dental samples from approximal surfaces showing the highest diversity. Principal component analysis discriminated the profiles of the samples originating from shedding surfaces (mucosa of tongue, cheek and palate) from the samples that were obtained from solid surfaces (teeth).There was a large overlap in the higher taxa, "species-level" phylotypes and unique sequences among the three microbiomes: 84% of the higher taxa, 75% of the OTUs and 65% of the unique sequences were present in at least two of the three microbiomes. The three individuals shared 1660 of 6315 unique sequences. These 1660 sequences (the "core microbiome") contributed 66% of the reads. The overlapping OTUs contributed to 94% of the reads, while nearly all reads (99.8%) belonged to the shared higher taxa.
We obtained the first insight into the diversity and uniqueness of individual oral microbiomes at a resolution of next-generation sequencing. We showed that a major proportion of bacterial sequences of unrelated healthy individuals is identical, supporting the concept of a core microbiome at health.
Available from: Ole Fejerskov
- "n the beginning of the 1980's, data on root caries were very sparse (for review, see Nyvad and Fejerskov, 1982; Fejerskov and Nyvad, 1986). During the last decade, however, an increasing number of studies has dealt with this disease entity, epidemiologically (Beck, 1990), microbiologically (Bowden, 1990; Nyvad, 1993), and from a histopathologic (Fejerskov and Nyvad, 1992, 1993) point of view. "
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ABSTRACT: The large variety of diagnostic criteria used adds some uncertainty to comparisons of recent clinical and epidemiological data on root caries in Scandinavia. Nevertheless, it is apparent that the prevalence of frank carious cavities on the root among 60(+)-year-olds is about 30-40%. When inactive and recurrent lesions and fillings are included, the prevalence is almost 100% in 60(+)-year-olds. At this age, the mean number of root surface fillings is about 7, and the mean number of active caries lesions ranges from 0.9 to 3.4. The degree of gingival recession does not appear to be a direct measure of root caries risk in a population. When the number of teeth at risk is accounted for, the age-dependent increase in prevalence of root caries is very weak. Therefore, comparisons of root caries prevalence between populations are meaningful only when information on number of teeth present and teeth at risk is also available. Recent studies from various parts of the world have demonstrated that caries is ubiquitous in all populations and that caries progression continues throughout life. The impact of this on trends in prevalence and incidence of dental caries in adults is discussed in the light of what is known about the natural history of dental caries.
Available from: Gunnar Dahlén
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ABSTRACT: Giventhehypothesis that root caries istheresult of acidformation byacidogenic micro-organisms, thepresent study wasperformed torelate sucrose-induced pHresponse ofdentalplaqueon rootsurfaces tothemicrobial composition oftheoverlying plaque. Seventeen caries-active elderly Chinese withpoororal hygiene andwithbothsound andcarious rootsurfaces wereexamined. Plaque pH was measured before anduptoonehourafter acontrolled sucrose mouthrinse. Plaquesamples formicrobiologic analyses werecollected from2soundand2or3carious pH- measurement sites ineachsubject. Theprevalence ofthe following micro-organisms wasassessed as% oftotal viable countsonBrucella agar: Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga spp., Actinomyces viscosus, Actinomyces naeslundi, Streptococcus spp., S.sanguis, S.mitis, S.mutans, S. sobrinus, Lactobacillus spp., andCandida spp.There wasno difference inplaque pHresponse onsoundandcarious root surfaces. Theplaque pHresponse wasmorepronounced in themaxilla thaninthemandible forbothsoundandcarious sites. There wasnodifference inmicrobial composition of dental plaque onsoundandcarious rootsurfaces. ThepH response tosucrose wasthesameregardless ofthepresence orabsence ofmutansstreptococci. Ourresults thusdonot readily support thetraditional concept ofcaries formation.
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