Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population II - microbiological results

Newly identified pathogens in periodontitis: evidence from an association and an elimination study

We assessed the level of evidence for the presence of new periodontal pathogens by (i) comparing the occurrence of non-classical periodontal taxa between healthy vs. periodontitis patients (Association study); (ii) assessing the modifications in the prevalence and levels of these species after treatments (Elimination study). In the Association study, we compared the prevalence and levels of 39 novel bacterial species between periodontally healthy and periodontitis patients. In the Elimination study, we analyzed samples from periodontitis patients assigned to receive scaling and root planing alone or with metronidazole+ amoxicillin TID/ 14 days. Levels of 79 bacterial species (39 novel and 40 classic) were assessed at baseline, 3 and 12 months post-therapy. All samples were analyzed using Checkerboard DNA-DNA hybridization. Out of the 39 novel species evaluated, eight were categorized as having strong and four as having moderate association with periodontitis. Our findings suggest strong evidence supporting Lancefieldella rimae, Cronobacter sakazakii, Pluralibacter gergoviae, Enterococcus faecalis, Eubacterium limosum, Filifactor alocis, Haemophilus influenzae, and Staphylococcus warneri, and moderate evidence supporting Escherichia coli, Fusobacterium necrophorum, Spiroplasma ixodetis, and Staphylococcus aureus as periodontal pathogens. These findings contribute to a better understanding of the etiology of periodontitis and may guide future diagnostic and interventional studies.

Antimicrobial activity of Desplac® oral gel in the subgingival multispecies biofilm formation

Natural products are well-known due to their antimicrobial properties. This study aimed to evaluate the antimicrobial effect of Desplac® product (composed of Aloe Vera, Propolis Extract, Green Tea, Cranberry, and Calendula) on the subgingival biofilm. Two different protocols were used to treat the 33-species biofilms: (A) 2×/day (12/12  h) for 1  min with Desplac® or Noplak Toothpaste (Chlorhexidine + Cetylpyridinium Chloride) or Oral B ProGengiva (stannous Fluoride) or a placebo gel; (B) a 12-h use of the Desplac® product or 0.12% chlorhexidine gel or a placebo gel. After 7 days of biofilm formation, the metabolic activity (MA) and biofilm profile were determined by 2,3,5-triphenyltetrazolium chloride and Checker-board DNA-DNA hybridization, respectively. Statistical analysis used the Kruskal-Wallis test followed by Dunn's post-hoc. In protocol A, all treatments presented reduced MA compared to the placebo (p ≤ 0.05). The Desplac®-treated biofilm showed a similar microbial profile to other antimicrobials, although with higher bacterial total counts. In protocol B, MA of Desplac®-treated biofilms was lower than the placebo's MA but higher than chlorhexidine-treated biofilms (p ≤ 0.05). Pathogen levels in Desplac®-treated biofilms were lower than in placebo-treated biofilms and elevated compared to the chlorhexidine-treated biofilms (p ≤ 0.05). Desplac® inhibited the biofilm development and disrupted the mature subgingival biofilm, highlighting its effect on Tannerella forsythia counts.

Classic vs. Novel Antibacterial Approaches for Eradicating Dental Biofilm as Adjunct to Periodontal Debridement: An Evidence-Based Overview

Periodontitis is a multifactorial chronic inflammatory disease that affects tooth-supporting soft/hard tissues of the dentition. The dental plaque biofilm is considered as a primary etiological factor in susceptible patients; however, other factors contribute to progression, such as diabetes and smoking. Current management utilizes mechanical biofilm removal as the gold standard of treatment. Antibacterial agents might be indicated in certain conditions as an adjunct to this mechanical approach. However, in view of the growing concern about bacterial resistance, alternative approaches have been investigated. Currently, a range of antimicrobial agents and protocols have been used in clinical management, but these remain largely non-validated. This review aimed to evaluate the efficacy of adjunctive antibiotic use in periodontal management and to compare them to recently suggested alternatives. Evidence from in vitro, observational and clinical trial studies suggests efficacy in the use of adjunctive antimicrobials in patients with grade C periodontitis of young age or where the associated risk factors are inconsistent with the amount of bone loss present. Meanwhile, alternative approaches such as photodynamic therapy, bacteriophage therapy and probiotics showed limited supportive evidence, and more studies are warranted to validate their efficiency.

Did Omics change periodontal therapy?

The starting point for defining effective treatment protocols is a clear understanding of the etiology and pathogenesis of a condition. In periodontal diseases, this understanding has been hindered by a number of factors, such as the difficulty in differentiating primary pathogens from nonpathogens in complex biofilm structures. The introduction of DNA sequencing technologies, including taxonomic and functional analyses, has allowed the oral microbiome to be investigated in much greater breadth and depth. This article aims to compile the results of studies, using next-generation sequencing techniques to evaluate the periodontal microbiome, in an attempt to determine how far the knowledge provided by these studies has brought us in terms of influencing the way we treat periodontitis. The taxonomic data provided, to date, by published association and elimination studies using next-generation sequencing confirm previous knowledge on the role of classic periodontal pathogens in the pathobiology of disease and include new species/genera. Conversely, species and genera already considered as host-compatible and others less explored were associated with periodontal health as their levels were elevated in healthy individuals and increased after therapy. Functional and transcriptomic analyses also demonstrated that periodontal biofilms are taxonomically diverse, functionally congruent, and highly cooperative. Very few interventional studies to date have examined the effects of treatment on the periodontal microbiome, and such studies are heterogeneous in terms of design, sample size, sampling method, treatment provided, and duration of follow-up. Hence, it is still difficult to draw meaningful conclusions from them. Thus, although OMICS knowledge has not yet changed the way we treat patients in daily practice, the information provided by these studies opens new avenues for future research in this field. As new pathogens and beneficial species become identified, future randomized clinical trials could monitor these species/genera more comprehensively. In addition, the metatranscriptomic data, although still embryonic, suggest that the interplay between the host and the oral microbiome may be our best opportunity to implement personalized periodontal treatments. Therapeutic schemes targeting particular bacterial protein products in subjects with specific genetic profiles, for example, may be the futuristic view of enhanced periodontal therapy.

Adjunctive systemic antimicrobials for the non-surgical treatment of periodontitis

BACKGROUND

Systemic antimicrobials can be used as an adjunct to mechanical debridement (scaling and root planing (SRP)) as a non-surgical treatment approach to manage periodontitis. A range of antibiotics with different dosage and combinations are documented in the literature. The review follows the previous classification of periodontitis as all included studies used this classification.

OBJECTIVES

To assess the effects of systemic antimicrobials as an adjunct to SRP for the non-surgical treatment of patients with periodontitis.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases to 9 March 2020: Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, and Embase. The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) which involved individuals with clinically diagnosed untreated periodontitis. Trials compared SRP with systemic antibiotics versus SRP alone/placebo, or with other systemic antibiotics.

DATA COLLECTION AND ANALYSIS

We selected trials, extracted data, and assessed risk of bias in duplicate. We estimated mean differences (MDs) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 45 trials conducted worldwide involving 2664 adult participants. 14 studies were at low, 8 at high, and the remaining 23 at unclear overall risk of bias. Seven trials did not contribute data to the analysis. We assessed the certainty of the evidence for the 10 comparisons which reported long-term follow-up (≥ 1 year). None of the studies reported data on antimicrobial resistance and patient-reported quality of life changes. Amoxicillin + metronidazole + SRP versus SRP in chronic/aggressive periodontitis: the evidence for percentage of closed pockets (MD -16.20%, 95% CI -25.87 to -6.53; 1 study, 44 participants); clinical attachment level (CAL) (MD -0.47 mm, 95% CI -0.90 to -0.05; 2 studies, 389 participants); probing pocket depth (PD) (MD -0.30 mm, 95% CI -0.42 to -0.18; 2 studies, 389 participants); and percentage of bleeding on probing (BOP) (MD -8.06%, 95% CI -14.26 to -1.85; 2 studies, 389 participants) was of very low certainty. Only the results for closed pockets and BOP showed a minimally important clinical difference (MICD) favouring amoxicillin + metronidazole + SRP. Metronidazole + SRP versus SRP in chronic/aggressive periodontitis: the evidence for percentage of closed pockets (MD -12.20%, 95% CI -29.23 to 4.83; 1 study, 22 participants); CAL (MD -1.12 mm, 95% CI -2.24 to 0; 3 studies, 71 participants); PD (MD -1.11 mm, 95% CI -2.84 to 0.61; 2 studies, 47 participants); and percentage of BOP (MD -6.90%, 95% CI -22.10 to 8.30; 1 study, 22 participants) was of very low certainty. Only the results for CAL and PD showed an MICD favouring the MTZ + SRP group. Azithromycin + SRP versus SRP for chronic/aggressive periodontitis: we found no evidence of a difference in percentage of closed pockets (MD 2.50%, 95% CI -10.19 to 15.19; 1 study, 40 participants); CAL (MD -0.59 mm, 95% CI -1.27 to 0.08; 2 studies, 110 participants); PD (MD -0.77 mm, 95% CI -2.33 to 0.79; 2 studies, 110 participants); and percentage of BOP (MD -1.28%, 95% CI -4.32 to 1.76; 2 studies, 110 participants) (very low-certainty evidence for all outcomes). Amoxicillin + clavulanate + SRP versus SRP for chronic periodontitis: the evidence from 1 study, 21 participants for CAL (MD 0.10 mm, 95% CI -0.51 to 0.71); PD (MD 0.10 mm, 95% CI -0.17 to 0.37); and BOP (MD 0%, 95% CI -0.09 to 0.09) was of very low certainty and did not show a difference between the groups. Doxycycline + SRP versus SRP in aggressive periodontitis: the evidence from 1 study, 22 participants for CAL (MD -0.80 mm, 95% CI -1.49 to -0.11); and PD (MD -1.00 mm, 95% CI -1.78 to -0.22) was of very low certainty, with the doxycycline + SRP group showing an MICD in PD only. Tetracycline + SRP versus SRP for aggressive periodontitis: we found very low-certainty evidence of a difference in long-term improvement in CAL for the tetracycline group (MD -2.30 mm, 95% CI -2.50 to -2.10; 1 study, 26 participants). Clindamycin + SRP versus SRP in aggressive periodontitis: we found very low-certainty evidence from 1 study, 21 participants of a difference in long-term improvement in CAL (MD -1.70 mm, 95% CI -2.40 to -1.00); and PD (MD -1.80 mm, 95% CI -2.47 to -1.13) favouring clindamycin + SRP. Doxycycline + SRP versus metronidazole + SRP for aggressive periodontitis: there was very low-certainty evidence from 1 study, 27 participants of a difference in long-term CAL (MD 1.10 mm, 95% CI 0.36 to 1.84); and PD (MD 1.00 mm, 95% CI 0.30 to 1.70) favouring metronidazole + SRP. Clindamycin + SRP versus metronidazole + SRP for aggressive periodontitis: the evidence from 1 study, 26 participants for CAL (MD 0.20 mm, 95% CI -0.55 to 0.95); and PD (MD 0.20 mm, 95% CI -0.38 to 0.78) was of very low certainty and did not show a difference between the groups. Clindamycin + SRP versus doxycycline + SRP for aggressive periodontitis: the evidence from 1 study, 23 participants for CAL (MD -0.90 mm, 95% CI -1.62 to -0.18); and PD (MD -0.80 mm, 95% CI -1.58 to -0.02) was of very low certainty and did not show a difference between the groups. Most trials testing amoxicillin, metronidazole, and azithromycin reported adverse events such as nausea, vomiting, diarrhoea, mild gastrointestinal disturbances, and metallic taste. No serious adverse events were reported.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence (for long-term follow-up) to inform clinicians and patients if adjunctive systemic antimicrobials are of any help for the non-surgical treatment of periodontitis. There is insufficient evidence to decide whether some antibiotics are better than others when used alongside SRP. None of the trials reported serious adverse events but patients should be made aware of the common adverse events related to these drugs. Well-planned RCTs need to be conducted clearly defining the minimally important clinical difference for the outcomes closed pockets, CAL, PD, and BOP.

Frequency of Porphyromonas gingivalis fimA in smokers and nonsmokers after periodontal therapy

Porphyromonas gingivalis is one of the most important Gram-negative anaerobe bacteria involved in the pathogenesis of periodontitis. P. gingivalis has an arsenal of specialized virulence factors that contribute to its pathogenicity. Among them, fimbriae play a role in the initial attachment and organization of biofilms. Different genotypes of fimA have been related to length of fimbriae and pathogenicity of the bacterium.

One year results of a randomized controlled clinical study evaluating the effects of non-surgical periodontal therapy of chronic periodontitis in conjunction with three or seven days systemic administration of amoxicillin/metronidazole

BACKGROUND

To evaluate the clinical outcomes 12 months after systemic administration of amoxicillin (AMX) and metronidazole (MET) adjunctive to subgingival debridement (SD) in patients with severe chronic periodontitis (sChP).

MATERIAL AND METHODS

102 patients with sChP were treated randomly as follows: SD within 2 consecutive days and placebo for 7 days (group A), SD+AMX+MET (both 500mg x3 times daily TID) for 3 days (group B), SD+AMX+MET (both 500mg x 3 TID) for 7 days (group C). At baseline, at 3-, 6-, and 12-months post-treatment probing pocket depth (PD), clinical attachment level (CAL), furcation involvement, bleeding on probing (BOP), full-mouth plaque score (FMPS) were determined. The reduction in the number of sites with PD≥6mm was defined as main outcome variable.

RESULTS

75 patients completed the study. At 12 months, all three treatment groups showed statistically significant improvements (p<0.001) of mean PD, CAL, BOP and number of sites with PD≥6mm compared to baseline. Mean residual PD were statistically significantly lower and CAL gain statistically significantly greater in the two antibiotic groups as compared to placebo. While PD reductions (p = 0.012) and CAL gain (p = 0.017) were statistically significantly higher in group C compared to group A, only the 3-day AB group showed statistically significantly fewer sites with PD≥6mm at 12 m (p = 0.003). The reduction in the number of sites with PD≥6 mm (primary outcome) showed no statistical significant differences between the 3 treatment groups. However, in both antibiotic groups significantly more patients compared to the placebo group reached a low risk for disease progression at 12 months (≤4 sites with PD≥5mm).

CONCLUSION

At 12 months, both adjunctive antibiotic protocols resulted in statistically significantly greater clinical improvements compared to placebo.

Systemic antibiotics in the treatment of periodontitis

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.

The concomitant administration of systemic amoxicillin and metronidazole compared to scaling and root planing alone in treating periodontitis: =a systematic review=

Background

The treatment of periodontitis begins with a non-surgical phase that includes scaling and root planing(SRP) and on occasion the use of systemic antibiotics. The goal was to systematically evaluate in systemic healthy adults the effect of the concomitant administration of amoxicillin (amx) and metronidazole (met) adjunctive to SRP compared to SRP alone.

Methods

The PubMed-MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched up to November 2014 to identify appropriate studies. Probing Pocket Depth (PD), Clinical Attachment Level (CAL), Bleeding on Pocket Probing(BOP) and Plaque Indices(PI) were selected as outcome variables. Based on the extracted data a meta-analysis was conducted.

Results

A total of 526 unique articles were found, 20 studies met the eligibility criteria. A meta-analysis showed that SRP + amx + met provided significantly better effects overall and more pronounced PD reduction in periodontal pockets initially measuring ≥6 mm (DiffM:-0.86 mm, p < 0.00001) and gain in CAL(DiffM:+0.75 mm, p = 0.0001). The meta-analysis for the secondary inflammatory parameter BOP showed that SRP + amx + met provided full mouth significantly greater reduction in BOP than SRP alone (DiffM:-6.98 %, p = 0.0001).

Conclusion

Adjunctive systemic amoxicillin and metronidazole medication to SRP significantly improved the clinical outcomes with respect to mean PD, CAL and BOP compared to SRP alone. There is moderate to strong evidence in support of the recommendation that adjunctive amx + met therapy to SRP significantly improves the clinical outcomes, with respect to mean PD and CAL compared to SRP alone especially in initially deep (≥6 mm) pockets. No major side effects associated with the intake of amx + met were reported. This treatment regimen is an efficacious, minimally invasive, practical and inexpensive approach for periodontitis therapy. The key components are mechanical tooth and pocket debridement, supportive treatment of the disease with systemic antibiotics and attention to proper self-care.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-015-0123-6) contains supplementary material, which is available to authorized users.

Full mouth periodontal debridement with or without adjunctive metronidazole gel in smoking patients with chronic periodontitis: A pilot study

BACKGROUND AND OBJECTIVE

The evidence of effectiveness of metronidazole (Mtz) as an adjunct therapy to periodontal procedure in the treatment of patients with chronic periodontitis is not conclusive. The aim of this study was to compare the effect of Mtz (delivered locally as a gel or systemically as a tablet) as an adjunctive therapy with full mouth periodontal debridement (1 h of ultrasonic calculus/plaque removal) in smokers with chronic periodontitis.

MATERIAL AND METHODS

This pilot study involved 30 smokers with at least six teeth with a clinical attachment loss of ≥ 5 mm and probing pocket depth (PPD) of ≥ 5 mm. They were randomly assigned into one of three groups (n = 10): (i) 3 g daily of placebo gel applied topically (using a dental tray with the gel overnight) + periodontal debridement; (ii) 3 g daily of a 15% Mtz benzoate gel applied topically (using a dental tray with the gel overnight) + periodontal debridement; and (iii) a daily single dose of 750 mg Mtz (Flagyl(®)) + periodontal debridement. Clinical parameters (visible plaque index, gingival bleeding index [GBI], relative attachment level and PPD) and quantitative analysis (by real-time polymerase chain reaction) of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia were assessed at baseline and at 1, 3 and 6 mo after periodontal debridement.

RESULTS

There was no statistically significant difference in the average GBI and visible plaque index values at baseline between the groups (p ≥ 0.05). There was no significant difference between groups in all parameters evaluated (p ≥ 0.05). Significant reductions in GBI at 3 and 6 mo were observed in all groups (p < 0.05). Significant reductions in both PPD and relative attachment level at 1, 3 and 6 mo were observed in all groups (p < 0.05). Significant reductions in bacterial levels at 7 and 30 d were observed in all groups (p < 0.05).

CONCLUSION

Adjunctive use of Mtz (gel or tablet) to periodontal debridement had similar clinical and microbiological improvement compared to treatment with placebo + periodontal debridement in smokers with chronic periodontitis up to 6 mo post-treatment. Further studies are necessary to confirm the clinical relevance of these findings.

An estimate of pocket closure and avoided needs of surgery after scaling and root planing with systemic antibiotics: a systematic review

BACKGROUND

Relevant benefits of adjunctive medication of antibiotica after conventional root surface debridement in terms of enhanced pocket depth (PD) reduction have been shown. However, means and standard deviations of enhanced reductions are difficult to translate into clinical relevant treatment outcomes such as pocket resolution or avoidance of additional surgical interventions. Accordingly, the aim of this systematic review was to calculate odds ratios for relevant cut-off values of PD after mechanical periodontal treatment with and without antibiotics, specifically the combination of amoxicilline and metronidazol, from published studies. As clinical relevant cut-off values "pocket closure" for PD ≤ 3mm and "avoidance of surgical intervention" for PD ≤ 5 mm were determined.

METHODS

The databases PubMed, Embase and Central were searched for randomized clinical studies assessing the beneficial effect of the combination of amoxicillin and metronidazole after non-surgical mechanical debridement. Titles, abstracts and finally full texts were scrutinized for possible inclusion by two independent investigators. Quality and heterogeneity of the studies were assessed and the study designs were examined. From published means and standard deviations for PD after therapy, odds ratios for the clinically relevant cut-off values were calculated using a specific statistical approach.

RESULTS

Meta-analyses were performed for the time points 3 and 6 month after mechanical therapy. Generally, a pronounced chance for pocket closure from 3 to 6 months of healing was shown. The administration of antibiotics resulted in a 3.55 and 4.43 fold higher probability of pocket closure after 3 and 6 months as compared to mechanical therapy alone. However, as the estimated risk for residual pockets > 5 mm was 0 for both groups, no odds ratio could be calculated for persistent needs for surgery. Generally, studies showed a moderate to high quality and large heterogeneity regarding treatment protocol, dose of antibiotic medication and maintenance.

CONCLUSION

With the performed statistical approach, a clear benefit in terms of an enhanced chance for pocket closure by co-administration of the combination of amoxicillin and metronidazole as an adjunct to non-surgical mechanical periodontal therapy has been shown. However, data calculation failed to show a benefit regarding the possible avoidance of surgical interventions.

Metronidazole alone or with amoxicillin as adjuncts to non-surgical treatment of chronic periodontitis: a secondary analysis of microbiological results from a randomized clinical trial

AIM

To evaluate the changes occurring in the subgingival microbial profile of subjects with generalized chronic periodontitis (ChP) treated by scaling and root planing (SRP) alone or with metronidazole (MTZ) or MTZ + amoxicillin(AMX). A secondary aim was to examine a possible added effect of chlorhexidine(CHX) to these therapies.

METHODS

One hundred and eighteen subjects were randomly assigned to receive SRP-only or with MTZ [400 mg/thrice a day (TID)] or MTZ + AMX (500 mg/TID) for 14 days. Half of the subjects in each group rinsed with 0.12% CHX twice a day (BID) for 2 months. Nine subgingival plaque samples/subject were analysed by checkerboard DNA–DNA hybridization for 40 bacterial species at baseline, 3, 6 and 12 months post-therapy.

RESULTS

At 12 months, the antibiotic-treated groups harboured lower mean counts and proportions of key periodontal pathogens than the SRP group (p < 0.05). These benefits were observed at initially deep and shallow sites. Initial reductions in periodontal pathogens obtained with SRP partially rebound after 12 months. CHX rinsing enhanced the microbiological effects of the MTZ + AMX treatment in shallow sites.

CONCLUSION

The adjunctive use of MTZ and MTZ + AMX results in a greater reduction in the levels of periodontal pathogens in generalized ChP subjects compared to SRP alone.

Concentrations of metronidazole in human plasma and saliva after tablet or gel administration

OBJECTIVES

The aim of this study was to determine the pharmacokinetic profile of metronidazole (Mtz) tablet and to compare Mtz gel and tablet concentrations in both blood plasma and saliva.

METHODS

In this randomized cross-over study with a 1-week washout period, 13 volunteers randomly received one (a single oral dose of 750 mg Mtz (Flagyl®--tablet) and 2) 3 g of 15% Mtz benzoate gel (applied by using a dental tray). The HPLC with ultraviolet detection was used to quantify plasma and saliva concentrations of Mtz. The pharmacokinetic parameters (PPs) areas under the curves from 0 to 48 h (AUC0-48) and from 0 to infinity (AUC0-∞), the maximum plasma concentration (C(max)), the time to C(max), volume of distribution and renal clearance were determined for Mtz tablet.

KEY FINDINGS

Considering the Mtz tablet, plasma showed higher Mtz concentration from 6 to 24 h after drug administration and the highest values concerning AUC0-48 h and AUC0-∞ than those obtained in saliva (P < 0.05). No significant differences were observed between plasma and saliva concentrations for Mtz gel.

CONCLUSIONS

The study showed that some PPs were higher in plasma (P < 0.05) than in saliva concerning Mtz tablet. Gel formulation had similar Mtz bioavailability in plasma and saliva resulting in systemic absorption.

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.

Microbial sampling process can change results of microbiological analysis in periodontitis diagnosis. A minireview

This minireview aims to verify the supposition that the microbial sampling process can change results of microbiological analysis in periodontitis diagnosis. The literature search via Pubmed yielded 52 appropriate articles for analysis. Of which 38% (20/52) described that the sampling sites were isolated from saliva, whereas 62% (32/52) did not. Also, 29% (15/52) declared that the microbial sampling was performed before probing pocket depth (PPD), whereas 71% (37/52) did not. Comparison of the results of microbiological analysis in these studies showed that the bacteria most frequently detected in periodontal pockets was variable. Therefore, a sampling process that includes both the microbial sample being taken before PPD and saliva isolation of the sampling sites is needed to ensure the accuracy of microbiological analysis in periodontitis diagnosis.

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.

Clinical and microbiological benefits of strict supragingival plaque control as part of the active phase of periodontal therapy

AIM

To compare the clinical and microbiological effects of scaling and root planing (SRP) alone or combined with mechanical [professional plaque control (PPC)] or chemical [chlorhexidine rinsing (CHX)] control of supragingival plaque in the treatment of chronic periodontitis.

MATERIAL AND METHODS

Sixty subjects were randomly assigned to receive SRP alone or combined with PPC (twice a week) or with CHX rinsing (twice a day). The adjunctive treatments began with SRP and were continued for 42 days. Clinical and microbiological examinations were performed at baseline, 2 and 6 months post-therapy. Subgingival plaque samples were analysed for 38 bacterial species by checkerboard DNA-DNA hybridization.

RESULTS

The two test treatments were more effective in improving probing depth and clinical attachment level (CAL) than SRP alone, even in intermediate and deep sites. CAL gain was better maintained in the CHX group. The most beneficial microbiological changes were observed in CHX-treated subjects, who showed a significant reduction in the proportions of red and orange complexes, as well as an increase in the proportions of the host-compatible bacterial species.

CONCLUSION

Strict plaque control performed during and after SRP improves periodontal treatment outcomes. The greatest microbiological and clinical benefits were observed with the use of CHX rinsing.

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.

Controlling systematic perioperative anaerobic contamination during sinus-lift procedures by using metronidazole: an innovative approach

BACKGROUND AND OBJECTIVES

Analysis of tomodensitometric controls following sinus grafts clearly demonstrates a quite systematic lack of homogeneity. Sinus contamination by anaerobic bacteria seems almost unavoidable during bone graft surgery, and this problem may jeopardize the healing process. The aim of this study was to characterize in a systematic way the nonhomogeneities observed at 1, 2, or 3 months postsurgery within allogenous sinus grafts, and to assess the possible influence of a 0.5% sterile solution of metronidazole incorporated in the sinus bone graft.

MATERIALS

This clinical study was conducted on 72 patients treated with single or bilateral sinus-lifts: 94 sinus elevations performed with freeze-dried bone allograft (Phoenix, TBF, Mions, France), with (test group) or without (control group) metronidazole. In the test group, each bone graft was hydrated with 2 mL of a 0.5% metronidazole solution, i.e., only 10 mg of metronidazole. All the patients went through a first presurgical computerized tomography (CT)-scan followed by a second scan performed at 1, 2, or 3 months postsurgery (which was used as the preimplant reference scan). For 11 patients, 2 postsurgical CT-scans were performed respectively at 10 days and 2 months. Using an arbitrary gray scale (Arbitrary Densitometric Unit) which functions according to the Hounsfield unit principle, the degree of radiographic homogeneity of the grafts was established. Density scattering provides some information on the homogeneity or nonhomogeneity of the bone graft.

RESULTS

The 12 grafts performed without metronidazole show significant nonhomogeneities at 1, 2, or 3 months. Moreover, when a CT-scan is performed during the first postoperative days (at 10 days), the presence of air bubbles in the graft is confirmed. The tomodensitometric aspects of all grafts treated with metronidazole in this series are absolutely identical: they show a high degree of homogeneity. Sixty-three cases (76.8%) are homogeneous, and 19 cases (23.2%) are significantly homogeneous. The time at which the control scan is performed (10 days, 1, 2, or 3 months) does not seem to influence significantly the degree of homogeneity assessed. In the control group, some inflammatory events associated with facial oedema were observed in 25% of the cases. In the test group, no such event was recorded for the 82 sinus-lifts treated with metronidazole.

CONCLUSION

A possible correlation may exist between the occurrence of non homogeneities within the bone grafts and the anaerobic bacterial contamination. The local use of a very small quantity of metronidazole (equivalent to only 1/20 of a common 200 mg oral tablet) could provide more security when performing sinus-lift procedures and an improved quality of the graft. This protocol should not be considered as an antibiotherapy, but only as way to limit the initial contamination of bone graft.

Etiological analysis of initial colonization of periodontal pathogens in oral cavity

It is unclear when the initial colonization by periodontal pathogens occurs in the oral cavity. Therefore, we report here the association between specific age groups and the time when the initial colonization by periodontal pathogens occurs in the oral cavity in such groups. Findings are based on an epidemiological analysis of the prevalence of five periodontal pathogens in the oral cavities of a wide range of age populations, from newborn to elderly, who were randomly selected in a geographic region of Brazil. These periodontal pathogens include Campylobacter rectus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Tannerella forsythia and were analyzed in the bacterial samples isolated from gingival sulcus, the dorsum of the tongue, and cheek mucosa of diverse age groups, using a bacterial DNA-specific PCR method. Results indicated that there are distinct age-related groups where initial colonization by the five periodontal pathogens examined in this study can be detected and that the presence of teeth is a permissive factor for colonization by P. gingivalis, P. intermedia, and T. forsythia. Although it remains unclear exactly how or when target pathogens colonize healthy subjects, an understanding of age-related groups does provide a potentially useful tool in the early detection and prevention of periodontitis in healthy individuals.

Minocycline HCl Microspheres Reduce Red-Complex Bacteria in Periodontal Disease Therapy

BACKGROUND

The objective of this trial was to measure the antimicrobial effects of a minocycline HCl microsphere (MM) local drug-delivery system when used as an adjunct to scaling and root planing (SRP). DNA probe analysis for 40 bacteria was used to evaluate the oral bacteria of 127 subjects with moderate to advanced chronic periodontitis.

METHODS

Subjects were randomly assigned to either SRP alone (N = 65) or MM + SRP (N = 62). The primary endpoints of this study were changes in numbers and proportions of the red-complex bacteria (RCB) and the sum of Porphyromonas gingivalis, Tannerella forsythia (formally T. forsythensis), and Treponema denticola relative to 40 oral bacteria at each test site from baseline to day 30. Numbers of RCB from the five test sites were averaged to provide a value for each subject.

RESULTS

MM + SRP reduced the proportion of RCB by 6.49% and the numbers by 9.4 x 10(5). The reduction in RCB proportions and numbers by SRP alone (5.03% and 5.1 x 10(5), respectively) was significantly less. In addition, MM + SRP reduced probing depth by 1.38 mm (compared to 1.01 mm by SRP alone), bleeding on probing was reduced by 25.2% (compared to 13.8% by SRP alone), and a clinical attachment level gain of 1.16 mm (compared to 0.80 mm by SRP alone) was achieved.

CONCLUSION

These observations support the hypothesis that RCBs are responsible for periodontal disease and that local antimicrobial therapy using MM + SRP effectively reduces numbers of RCBs and their proportions to a greater extent than SRP alone.

Antimicrobial therapy using a local drug delivery system (Arestin) in the treatment of peri-implantitis. I: Microbiological outcomes

OBJECTIVES

To assess the microbiological outcome of local administration of minocycline hydrochloride microspheres 1 mg (Arestin) in cases with peri-implantitis and with a follow-up period of 12 months.

MATERIAL AND METHODS

After debridement, and local administration of chlorhexidine gel, peri-implantitis cases were treated with local administration of minocycline microspheres (Arestin). The DNA-DNA checkerboard hybridization method was used to detect bacterial presence during the first 360 days of therapy.

RESULTS

At Day 10, lower bacterial loads for 6/40 individual bacteria including Actinomyces gerensceriae (P<0.1), Actinomyces israelii (P<0.01), Actinomyces naeslundi type 1 (P<0.01) and type 2 (P<0.03), Actinomyces odontolyticus (P<0.01), Porphyromonas gingivalis (P<0.01) and Treponema socranskii (P<0.01) were found. At Day 360 only the levels of Actinobacillus actinomycetemcomitans were lower than at baseline (mean difference: 1x10(5); SE difference: 0.34x10(5), 95% CI: 0.2x10(5) to 1.2x10(5); P<0.03). Six implants were lost between Days 90 and 270. The microbiota was successfully controlled in 48%, and with definitive failures (implant loss and major increase in bacterial levels) in 32% of subjects.

CONCLUSIONS

At study endpoint, the impact of Arestin on A. actinomycetemcomitans was greater than the impact on other pathogens. Up to Day 180 reductions in levels of Tannerella forsythia, P. gingivalis, and Treponema denticola were also found. Failures in treatment could not be associated with the presence of specific pathogens or by the total bacterial load at baseline. Statistical power analysis suggested that a case control study would require approximately 200 subjects.

Scaling and root planing and chlorhexidine mouthrinses in the treatment of chronic periodontitis: a randomized, placebo-controlled clinical trial

OBJECTIVE

Evaluation of the clinical and microbiological effects of scaling and root planing (SRP) alone or in combination with 0.12% chlorhexidine (CHX) rinsing.

METHODS

A blind, placebo-controlled, parallel-design, randomized clinical trial was conducted in 29 subjects with chronic periodontitis. Subjects were assigned to two therapeutic groups: control (SRP+placebo) and test (SRP+CHX during and up to 42 days post-therapy). Clinical and microbiological [N-benzoyl-dl-arginine-2-naphthylamide (BANA test)] examinations were performed at baseline, 42 and 63 days post-therapy.

RESULTS

Initially, intermediate sites (4-6 mm) in the test group showed less plaque accumulation, gingival bleeding, bleeding on probing and a greater reduction in attachment level and probing depth (PD) at 63 days after treatment. The initially deep sites (>6 mm) in the CHX group also showed a better reduction in plaque accumulation and in PD compared with the control group. Both therapies led to a microbiological improvement; however, the test subjects showed a higher frequency of BANA-negative sites after treatment, which was sustained over time (p<0.001). At 63 days, the control group presented 25 BANA-negative sites and 65 positive sites, and the test group 58 and 26, respectively.

CONCLUSION

The combination of CHX rinses and SRP leads to clinical benefits and to a better reduction in BANA-positive species.

Effects of metronidazole plus amoxicillin as the only therapy on the microbiological and clinical parameters of untreated chronic periodontitis

AIM

To determine the effect of metronidazole plus amoxicillin (M+A) as the sole therapy, on the subgingival microbiota of chronic periodontitis.

MATERIAL AND METHODS

Twenty-two patients with untreated chronic periodontitis were randomly assigned to a group that received M+A for 7 days, or to a group receiving scaling and root planing (SRP) and two placebos. Clinical measurements including sites with plaque, bleeding on probing (BOP), probing depth (PD) and attachment level (AL) were made at baseline, 3, 6, 9 and 12 months. Subgingival plaque samples were taken from all teeth at baseline 3, 6, 9 and 12 months for the counts of 40 subgingival species using checkerboard DNA-DNA hybridization.

RESULTS

Mean PD was reduced from 2.80+/-0.45 at baseline to 1.95+/-0.05 at 12 months (P<0.001) and from 2.39+/-0.41 to 1.95+/-0.10 (P<0.001) in the M+A- and SRP-treated patients, respectively. Corresponding values for relative mean AL were 10.07+/-1.30-9.77+/-0.34 (P<0.001) and 9.94+/-0.28-9.77+/-0.26 (P<0.001). Percentage of sites exhibiting BOP were 40.6+/-18.3-14.0+/-1.4 (P<0.001), and 38.5+/-5.1-19.0+/-2.8 (P<0.001) in the M+A and SRP groups, respectively. Mean total DNA probe counts and counts of the majority of the 40 test species were significantly reduced over time in both groups, with no significant differences detected at any time point between groups. At 12 months many of the species were still present at significantly lowered levels compared with their baseline counts in both groups.

CONCLUSIONS

Changes in clinical and microbiological parameters were similar after receiving systemically administered M+A as the sole therapy or after receiving SRP only.