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This case-controlled study examined clinical and microbiological parameters in Brazilian children and adolescents receiving orthodontic treatment using fixed orthodontic appliances or removable orthodontic appliances.The plaque index, gingival index, number of decayed, missing and filled teeth, and probing pocket depth was measured on each fully erupted tooth in 30 patients treated with fixed orthodontic appliances and an equal number of age and sex-matched control subjects. The same parameters were also measured in 18 patients treated with removable orthodontic appliances and an equal number of age and sex-matched control subjects. In the patients treated with fixed orthodontic appliances, subgingival plaque samples were collected from four teeth with orthodontic brackets and from four teeth with orthodontic bands. In the patients with removable appliances, subgingival plaque samples were collected from clasped maxillary permanent first molar teeth and from four unclasped permanent teeth. Samples of unstimulated whole saliva and samples from the dorsal surface of the tongue were also obtained from each subject. Each sample was analyzed for the presence of 19 target bacteria by dot blot. A subset of samples was examined by direct amplification of bacterial nucleic acids.Compared to their respective age and sex-matched controls, whole mouth means for plaque index and gingival index were significantly elevated in both the fixed and removable orthodontic groups. There was no difference in the DMFT. Subjects with fixed orthodontic appliances had a higher prevalence of each of the target species except for L. fermentum, Neisseriaceae and S. mutans. The prevalence of A. naeslundii and Streptococcus sp. was significantly higher on teeth with orthodontic brackets alone compared to teeth with both orthodontic bands and brackets. Subjects with removable orthodontic appliances had a higher prevalence of A. actinomycetemcomitans, C. rectus, E. corrodens, L. fermentum, Neisseriaceae, and spirochetes. The prevalence of Neisseriaceae was significantly higher on unclasped teeth compared to clasped teeth. There was no difference between sample sites for the target bacteria except for A. actinomycetemcomitans that was detected less frequently in saliva. Orthodontic patients demonstrated higher proportions of gram negative species by direct amplification of nucleic acids including species frequently associated with periodontal disease as well as rarely cultivable or non-cultivable species such as Abiotrophia defectiva, Gemella haemolysans, Granulicatella adiacens, Lautropia sp., Terrahaemophilus aromaticivorans, and TM7 bacterium.

To compare the effect of a dentifrice containing 0.3% triclosan and 1100 ppm fluoride and a control dentifrice containing 1100 ppm fluoride on plaque, gingiva and the oral microflora in a long-term study simulating clinical usage.159 subjects entered the clinical study and 80 were randomly selected to participate in the microbiological evaluation. 71 subjects completed the detailed evaluation of the oral microflora after 6 months use. Plaque was collected at baseline, 3 months, and 6 months, and examined by darkfield microscopy, Gram stain, immunofluorescence, and selective and non-selective media. Changes in antimicrobial susceptibilities were determined for the first 6-month period and for 6 months post-therapy for 68 subjects who completed the entire study. Susceptibilities of whole plaque samples and MIC values for two pre-designated common plaque organisms, A. viscosus and V. parvula were performed.Multivariate ANOVA and non-parametric analyses revealed no statistical differences for any factor tested. No detrimental shifts were found in either; (1) the compositional make up of the normal flora, (2) the periodontopathic or cariogenic flora, or (3) the opportunistic flora in either group of dentifrice users. Both treatments resulted in decreases in Gram positive cocci over time. There was a reduction in spirochetes in the triclosan/fluoride group as compared to the control group. No overgrowth in opportunists, periodontal pathogens, or cariogenic flora was found in either group. No increase in the proportion of the whole plaque flora resistant to triclosan was found nor was an increase in the MIC values of either A. viscosus or V. parvula in either group. Overall, there appeared to be a general decrease in plaque bacteria in both groups over the course of the experiment.

Based on numerous microbiological studies performed over the past several decades, it is clear that mutans streptococci can cause human root caries. S. mutans fulfills the criteria for implicating bacteria in the etiology of a mixed infection. For example, S. mutans is found in high numbers in lesion sites, higher than on sound root surfaces in the same subject. Subjects make elevated antibody levels to S. mutans antigens. The organism produces a number of virulence factors including metabolic acid from dietary sucrose and extracellular polysaccharides which facilitate bacterial colonization of tooth surfaces. Eliminating or reducing the number of S. mutans reduces the number of root caries lesions and can even result in "healing" of incipient lesions. There is also data demonstrating the cariogenic potential of S. mutans in animal models. Clearly, S. mutans fulfills the aforementioned requirements. Further, there is also evidence to implicate Lactobacillus as being important in the pathogenesis of root caries by virtue of its association with S. mutans in these lesions. There is less recent evidence regarding the importance of Actinomyces in this disease. While this microorganism is present in root caries and while animal studies clearly point to their cariogenic potential, more recent studies with few exceptions fail to find much association between Actinomyces and root caries. There is an important caveat, however. The Actinomyces may have subspecies groups which are more highly virulent and more closely involved in the etiology of root caries than other groups. For example, A. viscosus serovar 2 is associated with root caries. This and other subspecies groups may produce certain virulence factors not found within Actinomyces species as a whole. For this group of microorganisms and for other potential pathogens, techniques in molecular biology such as 16S ribosomal RNA sequencing offers the hope of more precisely defining species and unraveling what may be largely problems in bacterial taxonomy. Ribosomal RNA sequencing may reveal taxonomic relationships not apparent with classical phenotypic or serologic analyses. Other molecular methods, such as DNA or RNA probes to specific virulence factors may also reveal relationships between clinical lesions and microorganisms possessing these virulence factors. Finally, there are clearly a number of additional species which may have importance in root surface caries as shown in some studies. These techniques can be used to identify the distribution of novel, even uncultivable bacteria in root caries lesions and in this way establish their role in this important disease.

Eighty-one human subjects completed a double-blind study which examined the effects of a 0.3% triclosan/2% Gantrez copolymer/0.243% sodium fluoride dentifrice on the microflora of supragingival dental plaque. Subjects were divided into an experimental group which performed normal oral hygiene with the triclosan/copolymer/fluoride dentifrice and a control group which also performed normal oral hygiene with the same dentifrice minus the triclosan/copolymer. At baseline, 10 weeks, and 28 weeks, supragingival dental plaque was collected from buccal and lingual surfaces of the four first molar teeth and assayed for: 1) bacterial morphotypes by phase contrast microscopy, 2) Actinobacillus actinomycetemcomitans, Actinomyces species, Bacteroides forsythus, Bacteroides gingivalis, Bacteroides intermedius, Streptococcus mutans, Streptococcus sanguis, and Wolinella recta by immunofluorescence microscopy, and 3) Lactobacillus, yeast, enterics, Staphylococcus, aerobes and anaerobes by bacterial culture. After 28 weeks' use of their respective dentifrices, changes in the supragingival plaque microflora of the subjects were similar between the triclosan/copolymer/fluoride dentifrice group and the control dentifrice group, except for statistically significant reductions in fusiforms, spirochetes and staphylococci and significant increases in S. sanguis in the triclosan/copolymer/fluoride dentifrice group, as compared to the control dentifrice group. The subject population was unusual in the presence of enteric species and anaerobes found in supragingival plaque sites. This study indicates that the use of a dentifrice containing 0.3% triclosan and 2% Gantrez copolymer over an extended period of time (28 weeks) does not result in shifts in the microflora of supragingival plaque favoring the growth of either opportunistic or pathogenic bacterial species.