Influence of Surface Modifications on Bacterial Adherence to Implant Abutment Materials

The purpose of this study was to investigate the effects of various titanium and zirconia polishing protocols on the colonization of oral bacteria. Titanium and zirconia discs were divided into five groups: unpolished (control, UNP) and polished with Brownie only (BRO), Brownie plus Greenie (BPG), Brownie plus Greenie plus Supergreenie (BGS), and CeraMaster Coarse plus CeraMaster polishing tips (CER). The samples were sterilized and immersed in unstimulated saliva, then incubated in a liquid suspension of Streptococcus gordonii (S gordonii). The number of attached bacteria were counted 48 hours after the diluted suspensions were inoculated. Data were analyzed with ANOVA and Tukey test (P < .05). For titanium discs, the average number of bacteria from each group (CFU/mm²) was 1.51 x 10³ for UNP; 3.71 x 10³ for BRO; 5.65 x 10³ for BPG; 8.99 x 10² for BGS; and 8.49 x 10² for CER. For zirconia, the averages were 2.87 x 10² for UNP; 3.16 x 10² for BRO; 3.50 x 10² for BPG; 1.83 x 10² for BGS; and 8.73 x 10¹ for CER. Inadequate polishing roughens surfaces and promotes microbial adhesion to titanium and zirconia. Sequential polishing to the finest-finish polishing tips minimizes bacterial adherence to abutment surfaces. Zirconia exhibited less bacterial adhesion than titanium.

Editorial Comments to the Special Issue: "Aggregatibacter actinomycetemcomitans-Gram-Negative Bacterial Pathogen"

Aggregatibacter actinomycetemcomitans is a periodontal pathogen colonizing the oral cavity in many individuals of the human population. It is equipped with several potent virulence factors that can cause cell death and induce or evade the host inflammatory response. Both harmless and highly virulent genotypes of the bacterium have emerged because of the large genetic diversity within the species. The oral condition and age, as well as the geographic origin of the individual, influence the risk to be colonized by a virulent genotype of the bacterium. In the present editorial, the different genetic and virulence properties of A. actinomycetemcomitans will be addressed in relation to the publications in this Special Issue.

Association of pharyngitis with oral antibiotic use for the treatment of acne: a cross-sectional and prospective cohort study

OBJECTIVE

To prospectively evaluate the association between antibiotics used to treat acne and pharyngitis.

DESIGN

Cross-sectional and 9-month prospective cohort.

SETTING

Urban university setting.

PARTICIPANTS

University students.

INTERVENTION

Participants were asked to fill out a survey form, were swabbed for culture, and had a visual examination for acne.

MAIN OUTCOME MEASURE

Report of pharyngitis.

RESULTS

In the cross-sectional study, 10 of the 15 students receiving oral antibiotics for acne reported an episode of pharyngitis in the previous 30 days, whereas 47 of the 130 students not receiving oral antibiotics, but who had acne, reported an episode of pharyngitis in the prior month. The unadjusted odds ratio (OR) (95% CI) associating current oral antibiotic use in acne patients with a self-reported episode of pharyngitis was 3.53 (95% CI, 1.14-10.95). In the cohort study, there were 358 female and 218 male participants; 36 (6.2%) received oral antibiotics for acne during the study, and 96 (16.6%) received topical antibiotics for acne. Using mixed model logistic regression, the OR was 4.34 (95% CI, 1.51-12.47) associating oral antibiotic use with pharyngitis. Less than 1% of participants were colonized by group A streptococcus, which was not associated with pharyngitis.

CONCLUSIONS

Our studies show that that the odds of reporting pharyngitis is more than 3 times baseline in patients receiving oral antibiotics for acne vs those who are not receiving oral antibiotics. The true clinical importance of these findings needs to be evaluated further by prospective studies, but this finding is not associated with group A streptococcus.

Bacterial chemotaxis. Cell flux model, parameter measurement, population dynamics, and genetic manipulation

In this paper, we summarized our recent efforts toward accomplishing four key goals important for control of microbial population dynamics in nonmixed systems: (1) derivation of a cell population flux model based on individual cell properties; (2) measurement of the population random motility and chemotaxis parameters appearing in this model using a simple experimental assay; (3) quantitative understanding of the effects of cell motility and chemotaxis properties on microbial population dynamics; and (4) manipulation of chemotactic responses by genetic modification.