Search

Despite widespread use, the impact of minocycline hydrochloride microspheres on the shifts of oral bacterial species resistant to minocycline remains unknown. This study aimed at examining the percentage and taxonomy of minocycline‐resistant isolates in saliva and subgingival plaque samples before and after minocycline microspheres application in periodontitis patients during maintenance. Patients received supra‐ and sub‐gingival debridement with (test) or without (control) minocycline microspheres application to sites with probing depth >4 mm and were clinically monitored at baseline, 1, 3, and 6 months. Samples were collected at baseline, 1 and 6 months and analyzed via cultivation with or without 4 μg/mL minocycline. Percentage of resistant strains was determined by colony counting and taxonomy by checkerboard DNA‐DNA hybridization. Significant clinical changes were sought with the Mann‐Whitney test and differences in percentage of resistant isolates with the Friedman and Mann‐Whitney tests. Groups showed similar clinical improvements. Mean percentage of resistant isolates rose at 1 month and decreased at 6 months in saliva and plaque samples in test group (P<0.05) but remained unchanged in control group. Percentage of resistant isolates of Gemella morbillorumand Eubacterium saburreumincreased significantly at 6 months in both groups. Antibiotic resistance by Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivaliswas either absent or infrequent. Minocycline microspheres result in transient selection of minocycline resistant species in saliva and subgingival plaque samples.

Aims: To assess the effects of different nutritional and atmospheric conditions on the density and bacterial diversity of ex vivo biofilms of individuals with advanced periodontitis. Materials and methods: Subgingival biofilm samples were collected from volunteers with advanced periodontitis and immediately sent for cultivation of ex vivo biofilms. The biofilms were cultured in Brain Heart Infusion (BHI) + 1% hemin + 5% sheep blood or in BHI + 5% bovine serum; under anaerobic or capnophilic conditions, for time intervals of up to 7 and 14 days. The microbial composition was analyzed by Checkerboard DNA-DNA hybridization. Results: Atmospheric condition had a greater influence on bacterial counts than the type of culture media used. Higher bacterial counts were observed in anaerobic than in capnophilic atmosphere condition, irrespective of the media used and the time of growth. The type of medium influenced diversity. Although, the 40 species assessed have been identified in all tested conditions, in capnophilic atmosphere and serum-enriched-media only 12 bacterial species were identified, and the counts of most of them were very low. Conclusions: The two different nutritional and atmospheric conditions tested allowed the growth of multispecies ex vivo biofilms. Anaerobic growth in enriched blood media provided the highest bacterial counts and the richest biofilm diversity. [ABSTRACT FROM AUTHOR]

To our knowledge, to date, no studies have comprehensively assessed the changes occurring in the subgingival microbiome of young patients with periodontitis treated by means of mechanical and antibiotic therapy. Thus, this study aimed to use next‐generation sequencing to evaluate the subgingival microbial composition of young patients with severe periodontitis treated with scaling and root planing and systemic metronidazole and amoxicillin. Subgingival samples from healthy individuals and shallow and deep sites from periodontitis patients were individually collected at baseline and 90 days post‐treatment. The samples were analyzed using 16S rRNA‐gene sequencing (MiSeq‐Illumina) and QIIME pipeline. Differences between groups for the microbiological data were determined using principal coordinate analysis (PCoA), linear mixed models, and the PERMANOVA test. One hundred samples were collected from 10 periodontitis patients and seven healthy individuals. PCoA analysis revealed significant partitioning between pre‐and post‐treatment samples. No major differences in the composition of the subgingival microbiota were observed between shallow and deep sites, at baseline or at 90‐days post‐treatment, and the microbiome of both site categories after treatment moved closer in similarity to that observed in periodontal health. Treatment significantly improved all clinical parameters and reduced the relative abundance of classical periodontal pathogens and of Fretibacterium fastidiosum, Eubacterium saphenum, Porphyromonas endodontalis, Treponema medium, Synergistetes, TM7, and Treponemaspp, and increased that of Actinomyces, Rothia, Haemophilus, Corynebacterium, and Streptococcispp. Mechanical treatment associated with metronidazole and amoxicillin promoted a beneficial change in the microbiome of young individuals with severe periodontitis.

Objective: The selection of proper outcome measures is a critical step in clinical research. Most randomized clinical trials (RCTs) assessing the effects of initial anti-infective periodontal therapies use surrogate outcomes as primary outcome variables, such as mean changes in probing depth (PD) or in clinical attachment. However, these parameters do not reflect disease remission/control at patient level, which has led to subjective interpretations of the data from RCTs and Systematic Reviews. Based on a comprehensive analysis of 724 patients from USA, Germany and Brazil treated for periodontitis, this paper suggests that the clinical endpoint of "≤4 sites with PD≥5mm" is effective in determining disease remission/control after active periodontal treatment and therefore, may represent a pertinent endpoint for applying the treat-to-target concept in RCTs. Furthermore, regression models showed that the presence of >10% and >20% sites with bleeding on probing in the mouth post-treatment increases the risk of a patient leaving the endpoint from 1-2 years (OR=3.5 and 8.7, respectively). Researchers are encouraged to present results on this outcome when reporting their trials, as this will allow for an objective comparison across studies and facilitate systematic reviews, and consequently, the extrapolation of data from research to clinical practice. [ABSTRACT FROM AUTHOR]

The selection of proper outcome measures is a critical step in clinical research. Most randomized clinical trials (RCTs) assessing the effects of initial anti-infective periodontal therapies use surrogate outcomes as primary outcome variables, such as mean changes in probing depth (PD) or in clinical attachment. However, these parameters do not reflect disease remission/control at patient level, which has led to subjective interpretations of the data from RCTs and Systematic Reviews. Based on a comprehensive analysis of 724 patients from USA, Germany and Brazil treated for periodontitis, this paper suggests that the clinical endpoint of "≤4 sites with PD≥5mm" is effective in determining disease remission/control after active periodontal treatment and therefore, may represent a pertinent endpoint for applying the treat-to-target concept in RCTs. Furthermore, regression models showed that the presence of >10% and >20% sites with bleeding on probing in the mouth post-treatment increases the risk of a patient leaving the endpoint from 1-2 years (OR=3.5 and 8.7, respectively). Researchers are encouraged to present results on this outcome when reporting their trials, as this will allow for an objective comparison across studies and facilitate systematic reviews, and consequently, the extrapolation of data from research to clinical practice. [ABSTRACT FROM AUTHOR]

ABSTRACTChronic periodontitis is one of the most prevalent human diseases and is caused by dysbiosis of the subgingival microbiota. Treatment involves primarily mechanical disruption of subgingival biofilms and, in certain cases, adjunctive use of systemic antibiotic therapy. In vitrobiofilm models have been developed to study antimicrobial agents targeting subgingival species. However, these models accommodate a limited number of taxa, lack reproducibility, and have low throughput. We aimed to develop an in vitromultispecies biofilm model that mimics subgingival plaque, to test antimicrobial agents. Biofilms were cultivated using the Calgary Biofilm Device and were exposed to amoxicillin (AMX), metronidazole (MTZ), azithromycin (AZM), and AMX-MTZ at four different concentrations for 12, 24, or 36 h. Chlorhexidine (CHX) (0.12%) was used as the positive control. The compositions of the biofilms were analyzed by checkerboard DNA-DNA hybridization, and the percent reduction in biofilm metabolic activity was determined using 2,3,5-triphenyltetrazolium chloride and spectrophotometry. Thirty-five of the 40 species used in the inoculum were consistently recovered from the resulting in vitrobiofilms. After 36 h of exposure at the 1:27 dilution, AMX-MTZ reduced metabolic activity 11% less than CHX (q= 0.0207) but 54% more than AMX (q= 0.0031), 72% more than MTZ (q= 0.0031), and 67% more than AZM (q= 0.0008). Preliminary evidence of a synergistic interaction between AMX and MTZ was also observed. In summary, we developed reproducible biofilms with 35 subgingival bacterial species, and our results suggested that the combination of AMX and MTZ had greater antimicrobial effects on these in vitromultispecies biofilms than expected on the basis of the independent effects of the drugs.

Background:The aim of this study is to explore relationships among serum adipokines, vitamin D, and clinical and microbial parameters of chronic periodontitis before and after treatment. Methods:Weight, height, and smoking status were recorded for 56 patients with chronic periodontitis. Plaque, gingivitis, bleeding on probing, suppuration, probing depth, and clinical attachment level were measured at all teeth present. Subgingival biofilm samples from each tooth were analyzed for levels of 40 bacterial species using checkerboard DNA–DNA hybridization. Serum levels of interleukin‐6 (IL‐6), tumor necrosis factor‐α, adiponectin, leptin, resistin, and vitamin D were measured at baseline. Sample collection was then performed in a subset of the population 6 months after therapy (n = 17). Serum samples were analyzed using enzyme‐linked immunosorbent assay and immunoassays. Differences in clinical, microbial, and serum factors among groups were sought using the Mann‐Whitney Utest. Correlations among factors were evaluated using regression analysis. Effects of therapy were sought using the Wilcoxon signed rank test. Results:There were positive correlations between adiponectin/vitamin D and between IL‐6/leptin, negative correlations between IL‐6/vitamin D and leptin/vitamin D, but no associations between serum analytes and clinical or microbial parameters. Sex and body mass index were associated with levels of adipokines. Periodontal therapy improved clinical and microbiologic parameters but did not influence the levels of serum analytes. Conclusion:Adipokines and IL‐6 levels were affected by sex and body mass index. Serum analytes were not influenced by periodontal therapy.

Background:The objectives of this study were to measure levels of gingival crevicular fluid (GCF) biomarkers and subgingival bacterial species in periodontally healthy subjects and subjects with periodontitis to explore the relationships among these biomarkers, the subgingival microbiota, and the clinical parameters of periodontal disease. Methods:Clinical periodontal parameters were measured at six sites per tooth in 20 subjects with periodontitis and 20 periodontally healthy subjects. GCF and subgingival plaque samples were obtained from the mesio‐buccal aspect of every tooth. GCF levels of interleukin (IL)‐1β and IL‐8 and matrix metalloproteinase 8 were measured using checkerboard immunoblotting, and the levels of 40 bacterial taxa were quantified using checkerboard DNA‐DNA hybridization. A subset of “clinically healthy” sites from each group was analyzed separately. The significance of the differences between groups was determined using the unpaired ttest or the Mann‐Whitney test. Correlations among immunologic, microbiologic, and clinical data were determined using the Spearman rank correlation coefficient. Results:There were positive correlations among mean clinical parameters, mean levels of the three biomarkers, and the proportions of orange and red complex species (P<0.05). Clinically healthy sites from subjects with periodontitis had higher levels of IL‐1β and IL‐8 and higher proportions of orange and red complex species (P<0.05) than clinically healthy sites from periodontally healthy subjects. Red complex species were positively associated with the expression of all biomarkers (P<0.05), whereas purple and yellow complex species had negative correlations with IL‐1β and IL‐8 (P<0.05). Conclusions:Clinically healthy sites from subjects with periodontitis have higher levels of GCF biomarkers and periodontal pathogens than clinically healthy sites from periodontally healthy subjects. Different microbial complexes demonstrated distinct associations with specific GCF biomarkers.

Background:Because few studies have examined the critical issue of sampling reproducibility, the purpose of the present study was to examine the reproducibility of curet sampling of subgingival biofilms. Methods:Seven subgingival biofilm samples were taken successively, using a curet, from each of 80 sites and individually analyzed for their content of 40 bacterial species using checkerboard DNA‐DNA hybridization. One healthy site was sampled in each of 20 periodontally healthy subjects, and one sulcus/pocket of ≤3, 4 to 5, and ≥6 mm was sampled in each of 20 subjects with chronic periodontitis. The significance of differences in counts and proportions of individual species at the seven successive samplings for each probing depth (PD) category was determined using the Kruskal‐Wallis test. The reproducibility of species proportions at each PD category was measured using the coefficient of variation (CV), and the consistency of microbial profiles across samples was examined using the minimum similarity coefficient. Results:There was no significant difference in the mean proportions of the 40 test species in the seven successive samples in each of the four PD categories. The median CV for individual species in the same site was 0.79 (95% confidence interval [CI]: 0.76 to 0.82) compared to 1.76 (95% CI: 1.69 to 1.82) in samples from different sites. The within‐site mean minimum similarity coefficient (± SEM) was 51.2% ± 2.2%, and it was 27.9% ± 0.3% between sites. Conclusion:The proportions of species remained consistent in successive curet samples, indicating that the use of curets provided a reliable and reproducible method to obtain subgingival samples.