Marcelo Faveri

Composition of supra- and subgingival biofilm of subjects with healthy and diseased implants

OBJECTIVES The purpose of this study was to compare the microbial composition of supra- and subgingival biofilm in subjects with and without peri-implantitis. MATERIAL AND METHODS Forty-four subjects (mean age 48.9 +/- 13.51 years) with at least one implant restored and functional for at least 2 years were assigned to two groups: a peri-implantitis group (n=22), consisting of subjects presenting peri-implant sites with radiographic defects >3 mm, bleeding on probing and/or suppuration; and a control group (n=22), consisting of subjects with healthy implants. The clinical parameters evaluated were plaque index, gingival bleeding, bleeding on probing, suppuration, probing depth and clinical attachment level. Supra- and subgingival biofilm samples were taken from the deepest sites of each implant and analyzed for the presence of 36 microorganisms by checkerboard DNA-DNA hybridization. RESULTS Higher mean counts of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia were observed in the peri-implantitis group, both supra- and subgingivally (P<0.05). The proportions of the pathogens from the red complex were elevated, while host-compatible beneficial microbial complexes were reduced in diseased compared with healthy implants. The microbiological profiles of supra- and subgingival environments did not differ substantially within each group. CONCLUSION Marked differences were observed in the composition of supra- and subgingival biofilm between healthy and diseased implants. The microbiota associated with peri-implantitis was comprised of more periodontal pathogenic bacterial species, including the supragingival biofilm.

Microbiological diversity of generalized aggressive periodontitis by 16S rRNA clonal analysis

BACKGROUND/AIM The purpose of this study was to determine the bacterial diversity in the subgingival plaque of subjects with generalized aggressive periodontitis by using culture-independent molecular methods based on 16S ribosomal DNA cloning. METHODS Samples from 10 subjects with generalized aggressive periodontitis were selected. DNA was extracted and the 16S rRNA gene was amplified with the universal primer pairs 9F and 1525R. Amplified genes were cloned, sequenced, and identified by comparison with known 16S rRNA sequences. RESULTS One hundred and ten species were identified from 10 subjects and 1007 clones were sequenced. Of these, 70 species were most prevalent. Fifty-seven percent of the clone (40 taxa) sequences represented phylotypes for which no cultivated isolates have been reported. Several species of Selenomonas and Streptococcus were found at high prevalence and proportion in all subjects. Overall, 50% of the clone libraries were formed by these two genera. Selenomonas sputigena, the species most commonly detected, was found in nine of 10 subjects. Other species of Selenomonas were often present at high levels, including S. noxia, Selenomonas sp. EW084, Selenomonas sp. EW076, Selenomonas FT050, Selenomonas sp. P2PA_80, and Selenomonas sp. strain GAA14. The classical putative periodontal pathogens, such as, Aggregatibacter actinomycetemcomitans, was below the limit of detection and was not detected. CONCLUSION These data suggest that other species, notably species of Selenomonas, may be associated with disease in generalized aggressive periodontitis subjects.

Microbiological profile of untreated subjects with localized aggressive periodontitis

AIM The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP. MATERIAL AND METHODS One hundred and twenty subjects with LAgP (n=15), generalized aggressive periodontitis (GAgP, n=25), chronic periodontitis (ChP, n=30) or periodontal health (PH, n=50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA-DNA hybridization. RESULTS Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP. CONCLUSION A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.

Clinical and microbiological benefits of systemic metronidazole and amoxicillin in the treatment of smokers with chronic periodontitis: a randomized placebo-controlled study.

AIM The aim of this study was to evaluate the clinical and microbiological effects of scaling and root planing (SRP) alone or combined with metronidazole (MTZ) or with MTZ and amoxicillin (AMX) in the treatment of smokers with chronic periodontitis. METHODS A double-blind, placebo-controlled, randomized clinical trial was conducted in 43 subjects who received SRP alone (n=15) or combined with MTZ (400 mg 3 x per day, n=14) or with MTZ+AMX (500 mg 3 x per day, n=14) for 14 days. Clinical and microbiological examinations were performed at baseline and 3 months post-therapy. Subgingival samples were analysed by checkerboard DNA-DNA hybridization. RESULTS Subjects receiving MTZ+AMX showed the greatest improvements in mean probing depth and clinical attachment level. Both antibiotic therapies led to additional clinical benefits over SRP alone in initially shallow, intermediate, and deep sites. The SRP+MTZ+AMX therapy led to the most beneficial changes in the subgingival microbial profile. These subjects showed significant reductions in the mean counts and proportions of periodontal pathogens such as Tannerella forsythia, Porphyromonas gingivalis and Treponema denticola, and the greatest increase in proportions of host-compatible species. CONCLUSION Significant advantages are observed when systemic antibiotics are combined with SRP in the treatment of smokers with chronic periodontitis. The greatest benefits in clinical and microbiological parameters are achieved with the use of SRP+MTZ+AMX.

Short‐term benefits of the adjunctive use of metronidazole plus amoxicillin in the microbial profile and in the clinical parameters of subjects with generalized aggressive periodontitis

AIM The aim of this study was to evaluate the clinical and microbiological effects of scaling and root planing (SRP) alone or combined with metronidazole (MTZ) and amoxicillin (AMX) in the treatment of subjects with generalized aggressive periodontitis (GAgP). MATERIALS AND METHODS A double-blind, placebo-controlled, randomized clinical trial was conducted in 30 subjects receiving SRP alone or combined with MTZ (400 mg 3 x per day) and AMX (500 mg 3 x per day) for 14 days. Clinical and microbiological examinations were performed at baseline and 3 months post-SRP. Nine subgingival plaque samples per subject were analysed using checkerboard DNA-DNA hybridization. RESULTS Subjects receiving MTZ and AMX showed the greatest improvements in the mean full-mouth probing depth and clinical attachment level and at initially intermediate and deep sites. The most beneficial changes in the microbial profile were also observed in the MTZ+AMX group, which showed the lowest proportions of the red complex as well as a significant decrease in the proportions of the orange complex after treatment. The antibiotic therapy also reduced the levels of Aggregatibacter actinomycetemcomitans at initially deep sites. CONCLUSION Subjects with GAgP significantly benefit from the adjunctive use of MTZ and AMX. The short-term advantages are observed in the clinical and microbiological parameters.

Relationships between subgingival microbiota and GCF biomarkers in generalized aggressive periodontitis.

AIM To examine relationships between subgingival biofilm composition and levels of gingival crevicular fluid (GCF) cytokines in periodontal health and generalized aggressive periodontitis (GAP). MATERIALS AND METHODS Periodontal parameters were measured in 25 periodontally healthy and 31 GAP subjects. Subgingival plaque and GCF samples were obtained from 14 sites from each subject. Forty subgingival taxa were quantified using checkerboard DNA-DNA hybridization and the concentrations of eight GCF cytokines were measured using Luminex. Cluster analysis was used to define sites with similar subgingival microbiotas in each clinical group. Significance of differences in clinical, microbiological and immunological parameters among clusters was determined using the Kruskal-Wallis test. RESULTS GAP subjects had statistically significantly higher GCF levels of interleukin-1beta (IL-1beta) (p<0.001), granulocyte-macrophage colony-stimulating factor (GM-CSF) (p<0.01) and IL-1beta/IL-10 ratio (p<0.001) and higher proportions of Red and Orange complex species than periodontally healthy subjects. There were no statistically significant differences in the mean proportion of cytokines among clusters in the periodontally healthy subjects, while the ratio IL-1beta/IL-10 (p<0.05) differed significantly among clusters in the aggressive periodontitis group. CONCLUSIONS Different subgingival biofilm profiles are associated with distinct patterns of GCF cytokine expression. Aggressive periodontitis subjects were characterized by a higher IL-1beta/IL-10 ratio than periodontally healthy subjects, suggesting an imbalance between pro- and anti-inflammatory cytokines in aggressive periodontitis.

Serum Levels of Cytokines in Subjects With Generalized Chronic and Aggressive Periodontitis Before and After Non-Surgical Periodontal Therapy: A Pilot Study

BACKGROUND The emergence of periodontal medicine has increased interest in defining the serologic profiles of inflammatory mediators in subjects with periodontitis. Thus, the aim of this pilot study is to evaluate the serum levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, and interleukin (IL)-4, -17, and -23 in subjects with generalized chronic periodontitis (GCP) and generalized aggressive periodontitis (GAgP) before and after non-surgical periodontal therapy. METHODS Cytokines were measured by enzyme-linked immunosorbent assay in serum samples taken from 42 systemically healthy subjects divided according to periodontal status into subjects with GAgP (n = 14) and GCP (n = 14) and periodontally healthy (PH) subjects (n = 14). In addition, the levels of cytokines were reassessed at 6 months after periodontal therapy in the periodontitis groups. Clinical parameters were also evaluated at baseline and 6 months post-therapy. RESULTS After therapy, both periodontitis groups demonstrated a significant improvement in clinical periodontal status (P <0.05). At baseline, concentrations of TNF-alpha (P = 0.0006) and IL-17 (P = 0.02) were significantly higher in the GAgP group compared to the other groups. There was a significant decrease in serum concentrations of TNF-alpha (P = 0.03) and IL-17 (P = 0.04) at 6 months post-therapy in the GAgP group (P <0.05). The concentration of TNF-alpha remained elevated in the GAgP group compared to the PH group at 6 months post-therapy (P = 0.04). CONCLUSIONS Subjects with GAgP presented higher levels of TNF-alpha and IL-17 than subjects with GCP and PH subjects. In addition, although the serum levels of these cytokines improved significantly as a result of periodontal therapy, the levels of TNF-alpha remained higher in subjects with GAgP compared to PH subjects.

Clinical and microbiological benefits of metronidazole alone or with amoxicillin as adjuncts in the treatment of chronic periodontitis: a randomized placebo-controlled clinical trial.

AIM To evaluate the effects of the adjunctive use of metronidazole (MTZ) or MTZ+amoxicillin (AMX) in the treatment of generalized chronic periodontitis (ChP). MATERIALS AND METHODS Fifty-one subjects (n=17/group) were randomly assigned to receive scaling and root planing (SRP) only or combined with MTZ (400 mg t.i.d.) or MTZ+AMX (500 mg t.i.d.) for 14 days. Clinical and microbiological examinations were performed at baseline and 3 months post-SRP. Nine plaque samples/subject were analysed by checkerboard DNA-DNA hybridization for 40 bacterial species. RESULTS Subjects receiving MTZ+AMX exhibited a greater mean gain of clinical attachment, reduction in probing depth (PD) in intermediate and deep sites and a lower percentage of sites with PD5 mm at 3 months, in comparison with those treated with SRP only (p<0.05). The major benefit from the adjunctive use of MTZ was a greater reduction in PD in deep sites. SRP+MTZ+AMX was the only treatment that significantly reduced the levels and proportions of all red complex pathogens and elicited a significantly greater beneficial change in the microbial profile in comparison with SRP only. CONCLUSION The adjunctive use of MTZ+AMX offers short-term clinical and microbiological benefits, over SRP alone, in the treatment of non-smokers subjects with generalized ChP. The added benefits of MTZ were less evident.

Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

Antibiotics are important adjuncts in the treatment of infectious diseases, including periodontitis. The most severe criticisms to the indiscriminate use of these drugs are their side effects and, especially, the development of bacterial resistance. The knowledge of the biological mechanisms involved with the antibiotic usage would help the medical and dental communities to overcome these two problems. Therefore, the aim of this manuscript was to review the mechanisms of action of the antibiotics most commonly used in the periodontal treatment (i.e. penicillin, tetracycline, macrolide and metronidazole) and the main mechanisms of bacterial resistance to these drugs. Antimicrobial resistance can be classified into three groups: intrinsic, mutational and acquired. Penicillin, tetracycline and erythromycin are broad-spectrum drugs, effective against gram-positive and gram-negative microorganisms. Bacterial resistance to penicillin may occur due to diminished permeability of the bacterial cell to the antibiotic; alteration of the penicillin-binding proteins, or production of β-lactamases. However, a very small proportion of the subgingival microbiota is resistant to penicillins. Bacteria become resistant to tetracyclines or macrolides by limiting their access to the cell, by altering the ribosome in order to prevent effective binding of the drug, or by producing tetracycline/macrolide-inactivating enzymes. Periodontal pathogens may become resistant to these drugs. Finally, metronidazole can be considered a prodrug in the sense that it requires metabolic activation by strict anaerobe microorganisms. Acquired resistance to this drug has rarely been reported. Due to these low rates of resistance and to its high activity against the gram-negative anaerobic bacterial species, metronidazole is a promising drug for treating periodontal infections.

Prevalence of Maxillary Sinus Septa in 1024 Subjects With Edentulous Upper Jaws: A Retrospective Study

Maxillary sinus floor augmentation has been routinely performed to optimize dental implant placement in the posterior maxilla. However, complications during a sinus grafting procedure, such as perforation of the Schneiderian membrane, have been reported. This complication is generally associated with the presence of maxillary septa. Therefore, the aim of this retrospective study was to evaluate the prevalence of maxillary sinus septae in completely edentulous subjects by means of panoramic radiography. A total of 1024 panoramic radiographs were evaluated by 3 calibrated examiners. From these radiographs, 307 maxillary septa were detected in 221 subjects (21.58%); 86 (8.40%) of the subjects showed maxillary septa in both maxillary sinuses. Logistic regression failed to detect any correlation between the presence of maxillary septa, age, and gender (P > .05). Within the limits of the study, the prevalence of maxillary septa in this Brazilian population was shown to be moderate, indicating that dentists must be aware of the presence of this anatomic structure during maxillary sinus elevation grafting.