Odila Pereira da Silva Rosa

Activity of endodontic antibacterial agents against selected anaerobic bacteria

The antimicrobial activity of substances used as antibacterial agents (solutions of 10% calcium hydroxide, camphorated paramonochlorophenol - PMCC, 2% chlorhexidine digluconate and 10% castor oil plant detergent) on anaerobic bacteria (Fusobacterium nucleatum ATCC 25586, Prevotella nigrescens ATCC 33563, Clostridium perfringens ATCC 13124 and Bacteroidesfragilis ATCC 25285), using a broth dilution technique, was evaluated in vitro. For determination of minimum inhibitory and minimum bactericide concentrations (MIC and MBC), two culture broths, Reinforced Clostridial Medium (RCM) and supplemented Brucella, standardized inoculum and serially diluted solutions were used. All antibacterial agents presented antimicrobial activity that varied for different bacteria. There were no differences in the performance of the two broths. Chlorhexidine digluconate was the most effective, with the lowest MICs, followed by castor oil detergent, PMCC and calcium hydroxide. C. perfringens and B. fragilis were the most resistant bacteria to all agents.

Clinical and microbiological evaluation of the periodontal status of children with unilateral complete cleft lip and palate.

Objective To compare periodontal conditions in children with and without cleft. Design Clinical examinations and microbiological analysis of 57 selected children, including 30 with unilateral complete cleft lip and palate (experimental group) and 27 without clefts (control group). Setting Hospital of Rehabilitation of Craniofacial Anomalies (HRCA) in Bauru, Sao Paulo, Brazil. Patients, Participants All children examined were healthy and between the ages of 5 and 6 years. Results The mean plaque index (PI) in the experimental group was higher (1.82 ± 0.3) than in the control group (1.63 ± 0.38), although this difference was not statistically significant. The mean gingival index (GI) in the experimental group (1.82 ± 0.38) was found to be significantly higher (p < .05) than that of the control group (0.79 ± 0.33). The cleft area in the experimental group, with a mean PI of 2.04 ± 0.58 and mean GI of 1.11 ± 0.26, compared with the posterior area, with a mean PI of 1.74 ± 0.37 and mean GI of 1.04 ± 0.26, showed a statistically significant difference only in the PI. Most of the children in both experimental and control groups presented a moderate PI degree (73.33% and 81.48%, respectively) and a high prevalence of mild gingivitis (53.33% and 70.37%, respectively). Analysis of the organisms showed that Prevotella nigrescens was detected in 16.67% of the experimental group and 11.11% of the control, whereas Porphyromonas gingivalis and Treponema denticola were not detected. Conclusion Children with clefts showed greater gingival inflammation, despite the same amount of plaque and prevalence of microorganisms.

Níveis de infecção de estreptococos do grupo mutans em gestantes

The CFU number of mutans streptococci in saliva has been used to indicate dental caries risk, as well as to assess the effectiveness or the need for preventive measures. Considering that the acquisition in early childhood of mutans streptococci is a risk factor for developing dental caries in children, and that the transmission of these bacteria is dependent of the mothers salivary levels, the oral status of 50 pregnant women aged between 16 to 37 years (mean of 22.8 years) and of low socio-economic class, that attended a public medical center in Bauru-SP- Brazil for prenatal check up was studied. The dental examination was analysed through the DMF-T and DMF-S indexes using a mirror and an explorer, without radiographs. Paraffin-stimulated saliva was collected and handled according to the instructions of the Caritest-SM manufacturer (HERPO) for researching mutans groups. Of the 50 examined women, 8 (16%) had all teeth present, 39 (78%) had lost from 1 to 10 teeth and 4 (8%) had lost from 13 to 22 teeth. The DMF-S index registered a range from 5 to 114 (mean 37.1). Mutans streptococci were detected in 48 (96%) saliva samples, 4 (8%) of which had an infection level of 1x104 CFU/mL saliva; 10 (20%), 5x104 CFU/mL; and 4 (8%), 1x105 CFU/mL. Levels of infection considered more favorable to transmission were exhibited by 30 (60%) pregnant women 10 (20%) of which showed 2,5x105 CFU/mL, 12 (24%) 5x105 CFU/mL and 8 (16%) 1x106 CFU/mL. The results indicated that there are many pregnant women harbouring high levels of mutans streptococci, prompting the need of a preventive program directed to them in order to reduce or delay the intrafamilial transmission of these microorganisms.

In vitro effect of intracanal medicaments on strict anaerobes by means of the broth dilution method

The determination of bacterial susceptibility to intracanal medicaments is a necessity. Nevertheless, few studies utilize the proper methodology to carry out that evaluation with anaerobes. In this study, the steps of a broth dilution method, carried out in microplates (microdilution) and tubes (macrodilution), to test the effect of traditional intracanal medicaments on anaerobic bacteria are described. The results are presented as values of minimal inhibitory and bactericidal concentrations (MIC and MBC). Standardized inocula of the anaerobic bacteria Prevotella nigrescens (ATCC 33563), Fusobacterium nucleatum (ATCC 25586) and Clostridium perfringens (ATCC 13124), in reinforced Clostridium medium (RCM) and supplemented Brucella broth, were submitted to different concentrations of calcium hydroxide, chlorhexidine digluconate, camphorated paramonochlorophenol and formocresol solutions. The drugs were diluted in the same culture broths, in microplates and tubes, and were then incubated in anaerobiosis jars at 37 degrees C for 48 or 96 hours. The determination of MICs was carried out through visual and spectrophotometric readings, and the determination of MBCs, through the plating of aliquots on RCM-blood agar. For that kind of study, the macromethod with spectrophotometric reading should be the natural choice. MICs and MBCs obtained with the macromethod were compatible with the known clinical performance of the studied medications, and the values varied according to the bacteria and culture media employed. RCM was the most effective medium and C. perfringens, the most resistant microorganism.

Microrganismos cariogênicos em pacientes com insuficiência renal crônica em hemodiálise

Prevalence of dental caries, calculus index, stimulated salivary flow rate and levels of cariogenic microorganisms in saliva of patients with chronic renal failure undergoing hemodialysis were compared to those of normal subjects matched as to age and sex. No significant difference was detected regarding to DMF indexes, whole saliva flow or mutans streptococci and lactobacilli levels. However, when compared to the controls, patients showed a great need for dental treatment and dental plaque control instruction. They had higher indexes of decayed and missing surfaces and teeth; their filled surfaces and teeth indexes were lower and their calculus index was higher, demonstrating the necessity of a preventive and curative program to these special patients.

Emerging technologies for the prevention of dental caries. Are current methods of prevention sufficient for the high risk patient

Fluorides and chlorhexidine are technologies that are 65 and 40 years old, respectively. This overview argues that current methods of caries prevention are not effective for the high caries risk patient. In this review examples, arguments and recommendations are provided to address the high caries risk patient that include: failure of comprehensive chemical modalities treatments to address the high caries risk patient; ecological alteration - would this be an effective approach?; and biomaterials and oral microbiome research to address the high caries risk patient.

Aquisição de Estreptococos Mutans e Desenvolvimento de Cárie Dental em Primogênitos

Objetivo: Avaliar o momento de aquisicao de estreptococos mutans (EM), desenvolvimento de carie dental e as variaveis a eles associadas no decorrer de 23 meses, em primogenitos de familias de baixo nivel socioeconomico, desde os sete meses de idade. Metodo: A amostra foi selecionada com base em maes densamente colonizadas por EM, incluindo todos os membros de 14 familias que conviviam na mesma casa. Foram envolvidos no estudo 14 maes, pais e primogenitos e 8 parentes, na maioria avos. Exames clinicos e radiograficos iniciais determinaram os indices de carie e condicao periodontal dos adultos. Contagens de EM foram feitas em todos os adultos nas duas primeiras visitas. Nas criancas foram avaliados os niveis de EM, o numero de dentes e de caries, em quatro visitas. Resultados: A prevalencia de EM nos adultos foi alta, estando ausente em apenas um dos pais. EM foram detectados em 1, 2, 3 e 10 criancas, respectivamente nas visitas #1, 2, 3 e 4. A carie dental foi detectada em apenas tres criancas na ultima visita (aos 30 meses de idade), as quais apresentaram escores de EM significantemente maiores que as criancas sem carie, na mesma visita. Conclusao: Exclusivamente a condicao social de baixa renda e maes densamente colonizadas por EM nao sao sinonimo de colonizacao precoce e alta atividade de carie em criancas cuidadas em casa. O desenvolvimento de carie esta significantemente associado a escores elevados de EM nas criancas.

Quantificação da IgA secretora e sua correlação com os níveis salivares de estreptococos mutans e lactobacilos em crianças de 7 e 8 anos de idade

Forty children with ages of 7 and 8 years were selected for this investigation. They were classified in two groups according to wether the DMF-S and dmf-s indexes were equal or greater than zero. Samples of total stimulated saliva were obtained for the quantification of salivary IgA through the single radial immunodifusion technique, and of the salivary levels of mutans streptococci and lactobacilli. The results revealed that the concentrations of immunoglobulin were not different between the two groups, although they presented a positive correlation statistically significant at the 5% level with the salivary levels of lactobacilli for children with DMF-S and dmf-s indexes equal to zero.

Utilização de frutooligossacarídeo por estreptococos mutans in vitro

Neosugar is the trade name of a fructooligosaccharide (FOS) whose utilization by oral bacteria is not well known yet. The aim of the present study was to evaluate in vitro the effect of this product on the growth, fermentation and production of plaque by mutans streptococci: S. mutans, serotypes c, e and f, S. sobrinus, serotype d, S. downei, serotype h, S. cricetus, serotype a and S. rattus, serotype b. The evaluation of growth was carried out in Brain Heart Infusion (BHI) broths containing or not sucrose and FOS and in buffered broths having glucose or FOS as carbon sources, through optical density reading in spectrophotometer after 24 hours of incubation at 37 degrees C. Thereafter the reading of pH was made in the same media. The plaque produced on glass sticks in BHI broths containing 5% sucrose or FOS was weighed and carbohydrates and proteins were assayed. The possible cariogenicity of Neosugar was confirmed, since it sustained the same growth and intensity of fermentation of sucrose in BHI broth for all streptococci and permitted in vitro production of plaque by some of them. The amount of plaque as well as its content of proteins and carbohydrates were smaller than those produced with sucrose, although the difference was statistically significant only for carbohydrates.