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The purpose of this study was to compare biofilm formation on materials used for the fabrication of implant-supported dental prostheses. Twenty discs (D=15 mm, H=3 mm) were fabricated from one of the following restorative materials: yttria tetragonal zirconia polycrystal (Y-TZP); commercially pure titanium (CP-Ti); or heat-cured polymethyl methacrylate (PMMA). Specimens were polished following standard protocols. A non-contact profilometer (NPFLEX, Bruker, UK) was used to assess the surface roughness of each disk; results were reported as Ra (µm). Five strains of Gram-negative bacteria frequently associated with peri-implantitis, Aggregatibacter actinomycetemcomitans, Candida. albicans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia, were cultured on hand-polished discs fabricated from heat-cured PMMA, Y-TZP, or CP-Ti to compare biofilm formation on each type of material. The results were reported as colony-forming units per milliliter (CFU/mL). One-way ANOVA and post hoc tests were used to compare surface roughness and bacterial colonization on the respective materials. Statistical significance was set at a = 0.05. Discs fabricated from Y-TZP had a significantly higher Ra value (350 ± 30 µm) than either PMMA, or CP-Ti discs. Discs fabricated from either Y-TZP and CP-Ti may exhibit less colonization by bacteria associated with peri-mucositis and peri-implantitis. Y-TZP and CP-Ti are suggested materials for fabrication of implant-supported prostheses, considering biofilm formation. Resumo O objetivo deste estudo foi comparar a formação de biofilme em materiais utilizados na confecção de próteses dentárias implantossuportadas. Vinte discos (D = 15 mm, H = 3 mm) foram confeccionados com um dos seguintes materiais restauradores: zircônia tetragonal policristalina estabilizada por ítrio (Y-TZP); titânio comercialmente puro (CP-Ti); ou polimetilmetacrilato (PMMA). As amostras foram polidas seguindo protocolos padrão. Um perfilômetro sem contato (NPFLEX, Bruker, UK) foi usado para avaliar a rugosidade da superfície de cada disco; os resultados foram relatados como Ra (µm). Cinco cepas de bactérias Gram-negativas freqüentemente associadas a peri-implantite, Aggregatibacter actinomycetemcomitans, Candida. albicans, Porphyromonas gingivalis, Prevotella intermedia e Tannerella forsythia, foram cultivadas em discos polidos à mão feitos de PMMA, Y-TZP ou CP-Ti para comparar a formação de biofilme em cada tipo de material. Os resultados foram relatados como unidades formadoras de colônias por mililitro (UFC/mL). Análise de variância a um fator e testes post hoc foram usados para comparar a rugosidade da superfície e a colonização bacteriana nos respectivos materiais. A significância estatística foi estabelecida em a=0,05. Os discos feitos de Y-TZP tiveram um valor Ra significativamente mais alto (350 ± 30 µm) do que os discos de PMMA ou CP-Ti. Os discos fabricados com Y-TZP e CP-Ti podem apresentar menor colonização por bactérias associadas à perimucosite e peri-implantite. Considerando O Y-TZP e CP-Ti são materiais indicados para a confecção de próteses implantossuportadas, considerando a formação de biofilme

Aim: Oral malodor (halitosis) is a widespread condition caused by oral bacteria, particularly sulfur compound-producing species. This study assessed the effect of a triclosan/copolymer-containing dentifrice and a novel toothbrush with attached tongue cleaner on oral malodor and on the bacteria colonizing the dorsal surface of the tongue. Materials and Methods: 14 adult subjects with oral malodor defined as organoleptic scores ≥ 3 (scale 0 - 5) and mouth air sulfur levels ≥ 250 ppb participated in this study. Subjects were examined at baseline and after 28 days use of the triclosan dentifrice and toothbrush/tongue cleaner for: 1) organoleptic assessment; 2) mouth air sulfur levels; 3) tongue coating; and, 4) dorsal tongue surface microorganisms. Total bacterial numbers were assayed by microscopy. Dot-blot hybridization was used to assess a panel of 20 oral bacteria. Results: After 28 days, all subjects had significantly reduced organoleptic scores and mouth air sulfur levels compared to baseline (p 70% reduction in microbial numbers (p Enterococcus faecalis (p Peptostreptococcus micros (p Prevotella melaninogenica (p Porphyromonas gingivalis (p Solobacterium moorei (p

Aim: To test the hypothesis that antimicrobial agents can be incorporated into bis-acryl resin and that the material will inhibit bacterial growth in vitro. Materials and Methods: 0.5%, 1% and 2% triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) and 0.05% 0.01% and 0.15% cetylpyridinium chloride were incorporated into bis-acryl resins and molded into 1 mm × 10 mm discs. The discs were placed on bacterial culture media inoculated with Aggregatibacter actinomycetemcomitans strain Y4, Porphyromonas gingivalis strain SUNYaB A7A1-28 or Streptococcus gordonii strain 10558, incubated and examined for growth inhibition. Results: Triclosan-containing bisacryl resin discs produced dose-dependent zones of growth inhibition for A. actinomycetemcomitans but not S. gordonii or P. gingivalis. Cetylpyridinium chloride-containing discs produced dose-dependent zones of growth inhibition for Porphyromonas gingivalis and Streptococcus gordonii but not A. actinomycetemcomitans. Conclusion: Triclosan and cetylpyridinium chloride can be incorporated into bis-acryl resin and can inhibit the growth of plaque bacteria in a dose dependent manner. Bis-acryl resin containing antimicrobial agents may inhibit in vivo plaque accumulation and gingival inflammation.

We report the genome sequences of three clinical isolates of Tannerella forsythia from the subgingival plaque of periodontitis patients attending clinics at the School of Dental Medicine, University at Buffalo. The availability of these genome sequences will aid the understanding of the pathogenesis of periodontitis.

This study evaluated the antimicrobial activity of two commercially available 0·05% cetylpyridinium chloride (CPC) mouthrinses with or without alcohol and examined its antimicrobial activity on oral bacterial species including fresh clinical isolates compared to a chlorhexidine mouthrinse and a control fluoride mouthrinse without CPC. Two different approaches were used to evaluate antimicrobial activity. First, the minimum inhibitory concentration (MIC) was determined for each mouthrinse against a panel of 25 micro-organisms including species associated with dental caries, gingivitis and periodontitis. Second, supragingival dental plaque obtained from 15 adults was incubated with the four mouthrinses to evaluate antimicrobial activity on micro-organisms in oral biofilms. Both CPC mouthrinses exhibited lower MIC's, that is, greater antimicrobial activity, against oral Gram-negative bacteria especially periodontal pathogens and species implicated in halitosis such as Aggregatibacter actinomycemcomitans, Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia and Solobacterium moorei than the control mouthrinse. Ex-vivo tests on supragingival plaque micro-organisms demonstrated significantly greater antimicrobial activity by the CPC mouthrinses (>90% killing, P 98% killing, P

Aims: To determine minimal inhibitory concentrations (MICs) and the percentage of nonsusceptible bacteria – those still cultivable above a threshold concentration – in human supragingival dental plaque and saliva for antiplaque/antimicrobial agents including triclosan (TCS) and trichlorocarbanilide (TCC), and a new potential antimicrobial, 2-t-butyl-5-(4-t-butylphenyl)-phenol (DTBBP). Methods and Results: Broth and agar dilution-based MIC tests were performed using 28 oral and nonoral bacterial strains representing 17 species. MICs for TCS were lowest and more than 100-fold lower than DTBBP (P

Made available in DSpace on 2019-09-12T16:56:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2005 Objectives: Previous studies suggest differences between geographically and racially distinct populations in the prevalence of periodontopathic bacteria as well as greater periodontal destruction associated with infection by highly leucotoxic Actinobacillus actinomycetemcomitans. The present study examined these hypotheses in Brazilians with aggressive or chronic periodontitis. Materials and Methods: Clinical, radiographical, and microbiological assessments were performed on 25 aggressive periodontitis and 178 chronic periodontitis patients including 71 males and 132 females, 15-69 years of age. Results: The prevalence of Porphyromonas gingivalis was similar to that of other South American populations. The prevalence of A. actinomycetemcomitans and its highly leucotoxic subgroup was higher in Brazilians. Highly leucotoxic A. actinomycetemcomitans was more prevalent in aggressive periodontitis (chi(2) = 527.83) and positively associated with deep pockets (46 mm, chi(2) = 18.26) and young age (< 29 years, chi(2) = 18.68). Greater mean attachment loss was found in subjects with highly leucotoxic A. actinomycetemcomitans than in subjects with minimally leucotoxic (p = 0.0029) or subjects not infected (p = 0.0001). Conclusion: These data support the hypothesis of differences between populations in the prevalence of periodontopathic bacteria and of greater attachment loss in sites infected with highly leucotoxic A. actinomycetemcomitans. Detection of highly leucotoxic A. actinomycetemcomitans in children and adolescents may be a useful marker for aggressive periodontitis. SUNY Buffalo, Sch Dent Med, Buffalo, NY 14214 USA; Universidade de Taubaté (Unitau), Sao Paulo, Brazil

Actinobacillus actinomycetemcomitans is an oral pathogen that causes aggressive periodontitis as well as sometimes life-threatening, extra-oral infections. Iron regulation is thought to be important in the pathogenesis of A. actinomycetemcomitans infections and, consistent with this hypothesis, the fur gene has recently been identified and characterized in A. actinomycetemcomitans. In this study, 14 putatively Fur-regulated genes were identified by Fur titration assay (Furta) in A. actinomycetemcomitans, including afuA, dgt, eno, hemA, tbpA, recO and yfe – some of which are known to be Fur regulated in other species. A fur mutant A. actinomycetemcomitans strain was created by selecting for manganese resistance in order to study the Fur regulon. Comparisons between the fur gene sequences revealed that nucleotide 66 changed from C in the wild-type to T in the mutant strain, changing leucine to isoleucine. The fur mutant strain expressed a nonfunctional Fur protein as determined by Escherichia coli-based ferric uptake assays and Western blotting. It was also more sensitive to acid stress and expressed higher levels of minC than the wild-type strain. minC, which inhibits cell division in other bacterial species and whose regulation by iron has not been previously described, was found to be Fur regulated in A. actinomycetemcomitans by Furta, by gel shift assays, and by RT-qPCR assays for gene expression.

Made available in DSpace on 2021-07-14T10:48:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-06. Added 1 bitstream(s) on 2021-07-14T11:38:43Z : No. of bitstreams: 1 S1517-74912003000200016.pdf: 129290 bytes, checksum: 46a4a89815dea079ef03f222f2c12885 (MD5) O presente estudo avaliou a prevalência de Actinobacillus actinomycetemcomitans de máxima e mínima leucotoxicidade em indivíduos com doença periodontal. Foram analisadas amostras de placa bacteriana subgengival de 136 indivíduos, entre 14 e 76 anos de idade, com algum tipo de doença periodontal. Os parâmetros clínicos avaliados incluíram profundidade de sondagem (PS), índice de placa bacteriana (IPB) e índice de sangramento gengival (ISG). A presença de amostras de A. actinomycetemcomitans de máxima e mínima leucotoxicidade foi avaliada por reação em cadeia da polimerase (PCR). Os resultados foram analisados empregando-se teste qui-quadrado e análise de regressão logística. Quarenta e sete indivíduos apresentaram gengivite, 70 indivíduos periodontite crônica e 19 indivíduos periodontite agressiva. O teste qui-quadrado não demonstrou correlação significativa entre PS (chi2 = 0,73), IPB (chi2 = 0,35), ISG (chi2 = 0,09) e a presença de amostras de máxima leucotoxicidade. A. actinomycetemcomitans de máxima leucotoxicidade apresentou associação com indivíduos com idade inferior a 28 anos (chi2 = 22,06). Os resultados observados nessa população brasileira confirmam a forte associação existente entre amostras de A. actinomycetemcomitans de máxima leucotoxicidade e periodontite agressiva. This study examined the prevalence of highly and minimally leukotoxic Actinobacillus actinomycetemcomitans in patients with periodontal disease. Pooled subgingival plaque samples from 136 patients with some form of periodontal disease were examined. Subjects were between 14 and 76 years of age. Clinical examinations included periodontal pocket depth (PD), plaque index (PI) and bleeding index (BI). The obtained plaque samples were examined for the presence of highly or minimally leukotoxic A. actinomycetemcomitans strains by the polymerase chain reaction (PCR). Chi-square and logistic regression were performed to evaluate the results. Forty-seven subjects were diagnosed with gingivitis, 70 with chronic periodontitis and 19 with aggressive periodontitis. According to chi-square there was no significant correlation detected between PD (chi2 = 0.73), PI (chi2 = 0.35), BI (chi2 = 0.09) and the presence of the highly leukotoxic A. actinomycetemcomitans. The highly leukotoxic A. actinomycetemcomitans strains were correlated with subjects that were 28 years of age and younger (chi2 = 7.41). There was a significant correlation between highly leukotoxic A. actinomycetemcomitans and aggressive periodontitis (chi2 = 22.06). This study of a Brazilian cohort confirms the strong association between highly leukotoxic A. actinomycetemcomitans strains and the presence of aggressive periodontitis. State University of New York, School of Dental Medicine Universidade Estadual Paulista University of Taubaté Universidade Estadual Paulista

In several bacterial species, iron availability in host tissues is coordinated with the expression of virulence determinants through the fur gene product. Initial experiments showed that a cloned Escherichia coli fur gene probe hybridized to Southern blots of Actinobacillus actinomycetemcomitans strain JP2 (serotype b) chromosomal DNA. The A. actinomycetemcomitans fur gene was then cloned utilizing partial functional complementation of the fur mutant in E. coli strain H1780. Analysis of the cloned DNA sequence revealed a 438-bp open reading frame with a deduced 146-amino-acid sequence exhibiting 80% identity to Haemophilus influenzae Fur and 62% identity to E. coli Fur. The pUC Aafur gene probe (generated from JP2 serotype b) hybridized to representatives from all five A. actinomycetemcomitans serotypes as well as to two strains derived from monkeys, suggesting that fur is widely distributed in A. actinomycetemcomitans. Open reading frames having >70% identity with the E. coli and H. influenzae flavodoxin and gyrase A genes, respectively, were found. Expression of the A. actinomycetemcomitans fur gene product repressed fiu expression and siderophore production in E. coli . A gel shift assay demonstrated that the expressed A. actinomycetemcomitans Fur protein bound the bacterial fur consensus sequence. Further characterization of the fur gene product in A. actinomycetemcomitans may improve our understanding of its role in the pathogenesis of periodontal disease and may lead to specific therapeutic modalities.

The present study describes a method for amplifying DNA in Actinobacillus actinomycetemcomitans by using short, synthetic oligonucleotides of random sequence as primers in the polymerase chain reaction. Genomic DNA from each of 20 human isolates of A. actinomycetemcomitans was successfully amplified in a thermal cycler with a single synthetic primer (GGGTAACGCC) and reproducibly produced 14 different DNA amplification profiles (amplitypes). A. actinomycetemcomitans isolates from the same subject revealed the same amplitype. The arbitrarily primed polymerase chain reaction appears to be useful in characterizing human isolates of A. actinomycetemcomitans for studies of epidemiology and bacterial transmission.

Background Triclosan is a broad-spectrum antimicrobial agent used in toothpaste to reduce dental plaque, gingivitis and oral malodor. This community-level assessment evaluated the susceptibility of dental plaque bacteria to triclosan in samples collected over 19 years. Methods A total of 155 dental plaque samples were collected at eleven different times over 19 years from 58 adults using 0.3% triclosan, 2% copolymer, 0.243% sodium fluoride toothpaste and from 97 adults using toothpaste without triclosan. These included samples from 21 subjects who used triclosan toothpaste for at least five years and samples from 20 control subjects. The samples were cultured on media containing 0, 7.5 or 25 μg/ml triclosan. Descriptive statistics and p values were computed and a linear regression model and the runs test were used to examine susceptibility over time. Results Growth inhibition averaged 99.451% (91.209 - 99.830%) on media containing 7.5 μg/ml triclosan and 99.989% (99.670 - 100%) on media containing 25 μg/ml triclosan. There was no change in microbial susceptibility to triclosan over time discernible by regression analysis or the runs test in plaque samples taken over 19 years including samples from subjects using a triclosan-containing dentifrice for at least five years. Conclusions This community-level assessment of microbial susceptibility to triclosan among supragingival plaque bacteria is consistent with the long-term safety of a 0.3% triclosan, 2% copolymer, 0.243% sodium fluoride dentifrice.