Metronidazole in the treatment of localized juvenile periodontitis

Europe's contribution to the evaluation of the use of systemic antimicrobials in the treatment of periodontitis

This narrative review celebrates Europe's contribution to the current knowledge on systemically administered antimicrobials in periodontal treatment. Periodontitis is the most frequent chronic noncommunicable human disease. It is caused by dysbiotic bacterial biofilms and is commonly treated with subgingival instrumentation. However, some sites/patients do not respond adequately, and its limitations and shortcomings have been recognized. This has led to the development of alternative or adjunctive therapies. One is the use of antimicrobials to target bacteria in subgingival biofilms in the periodontal pocket, which can be targeted directly through the pocket entrance with a locally delivered antibiotic or systemically by oral, intravenous, or intramuscular methods. Since the early 20th century, several studies on systemic antibiotics have been undertaken and published, especially between 1990 and 2010. Europe's latest contribution to this topic is the first European Federation of Periodontology, S3-level Clinical Practice Guideline, which incorporates recommendations related to the use of adjuncts to treat stage I-III periodontitis. Understanding the etiopathogenesis of periodontal diseases, specifically periodontitis, has influenced the use of systemic periodontal antibiotic therapy. Randomized clinical trials and systematic reviews with meta-analyses have demonstrated the clinical advantages of adjunctive systemic antimicrobials. However, current recommendations are restrictive due to concerns about antibiotic misuse and the increase in microbial antibiotic resistance. European researchers have contributed to the use of systemic antimicrobials in the treatment of periodontitis through clinical trials and by providing rational guidelines. Nowadays, European researchers are exploring alternatives and directing clinical practice by providing evidence-based guidelines to limit the use of systemic antimicrobials.

Azithromycin as an adjunct to subgingival professional mechanical plaque removal in the treatment of grade C periodontitis: a systematic review and meta-analysis

The aim of this systematic review was to evaluate clinical and microbiological outcomes with the use of azithromycin as an adjunct to non-surgical subgingival professional mechanical plaque removal (PMPR) in the treatment of grade C periodontitis. Online database searches using high-level MeSH terms in a PICO structure were conducted along with hand-searching of relevant periodontal journals. Titles and abstracts of identified studies were independently reviewed by both authors and the full texts of studies meeting the inclusion criteria were independently reviewed. In total, 122 studies were identified through searches, of which 6 were included in the qualitative analysis and 4 in the meta-analysis. Three studies included in the meta-analysis were deemed at low risk of bias and 1 at serious risk. There were conflicting results on whether azithromycin reduced the number of subgingival pathogens or detectable subgingival Aggregatibacter actinomycetemcomitans between the included studies. The meta-analysis revealed a statistically significant probing depth reduction difference in favour of azithromycin compared to the control at 3 months (weighted mean difference [WMD]=−0.39 mm; 95% confidence interval [CI], −0.66 to −0.13 mm; I²=0%) and 12 months (WMD=−1.32 mm; 95% CI, −1.71 to −0.93 mm; I²=0%). The clinical attachment level change was also statistically significant in favour of azithromycin compared to the control at 3 months (WMD=−0.61 mm; 95% CI, −1.13 to −0.10 mm; I²=71%) and 12 months (WMD=−0.88 mm; 95% CI, −1.32 to −0.44 mm; I²=0%). Based upon these results, azithromycin offers additional improvements in some clinical parameters when used in conjunction with subgingival PMPR in patients with aggressive periodontitis over control groups. These improvements appear to be maintained for up to 12 months after treatment completion. However, due to a lack of well-designed studies, the conclusions that can be drawn from the available evidence are limited.

Aggregatibacter actinomycetemcomitans leukotoxin: From mechanism to targeted anti-toxin therapeutics

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium associated with localized aggressive periodontitis, as well as other systemic diseases. This organism produces a number of virulence factors, all of which provide some advantage to the bacterium. Several studies have demonstrated that clinical isolates from diseased patients, particularly those of African descent, frequently belong to specific clones of A. actinomycetemcomitans that produce significantly higher amounts of a protein exotoxin belonging to the repeats-in-toxin (RTX) family, leukotoxin (LtxA), whereas isolates from healthy patients harbor minimally leukotoxic strains. This finding suggests that LtxA might play a key role in A. actinomycetemcomitans pathogenicity. Because of this correlation, much work over the past 30 years has been focused on understanding the mechanisms by which LtxA interacts with and kills host cells. In this article, we review those findings, highlight the remaining open questions, and demonstrate how knowledge of these mechanisms, particularly the toxin's interactions with lymphocyte function-associated antigen-1 (LFA-1) and cholesterol, enables the design of targeted anti-LtxA strategies to prevent/treat disease.

Epigallocatechin gallate inhibits leukotoxin release by Aggregatibacter actinomycetemcomitans by promoting association with the bacterial membrane

The oral pathogen, Aggregatibacter actinomycetemcomitans, produces a number of virulence factors, including a leukotoxin (LtxA), which specifically kills human white blood cells, to provide a colonization advantage to the bacterium. Strains of A. actinomycetemcomitans that produce more LtxA have been more closely linked to disease, indicating that this toxin plays a key role in pathogenesis of the bacterium. Disruption of the activity of LtxA thus represents a promising approach to reducing the pathogenicity of the bacterium. Catechins are polyphenolic molecules derived from plants, which have shown potent antibacterial and antitoxin activities. We have previously shown that galloylated catechins are able to prevent LtxA delivery to host cells by altering the toxin's secondary structure and preventing binding to cholesterol on the host cell membrane. Here, we have investigated how one particular galloylated catechin, epigallocatechin gallate (EGCg), affects A. actinomycetemcomitans growth and toxin secretion. Our results demonstrate that EGCg, at micromolar concentrations, inhibits A. actinomycetemcomitans growth, as has been reported for other bacterial species. At subinhibitory concentrations, EGCg promotes LtxA production, but the toxicity of the bacterial supernatant against human immune cells is reduced. The results of our biophysical studies indicate that this seemingly contradictory result is caused by an EGCg-mediated enhancement of LtxA affinity for the bacterial cell surface. Together, these results demonstrate the potential of EGCg in the treatment of virulent A. actinomycetemcomitans infections.

Cranberry Proanthocyanidins Neutralize the Effects of Aggregatibacter actinomycetemcomitans Leukotoxin

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that has been strongly associated with localized aggressive periodontitis. The capacity of A. actinomycetemcomitans to produce a leukotoxin (LtxA) that activates pyroptosis in macrophages and induces the release of endogenous danger signals is thought to play a key role in the disease process. The aim of the present study was to investigate the effects of cranberry proanthocyanidins (PACs) on gene expression and cytotoxic activities of LtxA. We showed that cranberry PACs dose-dependently attenuate the expression of genes making up the leukotoxin operon, including ltxB and ltxC, in the two strains of A. actinomycetemcomitans tested. Cranberry PACs (≥62.5 µg/mL) protected macrophages against the cytotoxic effect of purified LtxA. Moreover, cranberry PACs reduced caspase-1 activation in LtxA-treated macrophages and consequently decreased the release of both IL-1β and IL-18, which are known as damage-associated molecular patterns (DAMPs) and contribute to the progression of periodontitis by increasing cell migration and osteoclastogenesis. In addition, cranberry PACs reduced the expression of genes encoding the P2X7 receptor and NALP3 (NACHT, LRR and PYD domains-containing protein 3), which play key roles in pore formation and cell death. Lastly, cranberry PACs blocked the binding of LtxA to macrophages and consequently reduced the LtxA-mediated cytotoxicity. In summary, the present study showed that cranberry PACs reduced LtxA gene expression in A. actinomycetemcomitans and neutralized the cytolytic and pro-inflammatory responses of human macrophages treated with LtxA. Given these properties, cranberry PACs may represent promising molecules for prevention and treatment of the aggressive form of periodontitis caused by A. actinomycetemcomitans.

Catechin-mediated restructuring of a bacterial toxin inhibits activity

BACKGROUND

Catechins, polyphenols derived from tea leaves, have been shown to have antibacterial properties, through direct killing of bacteria as well as through inhibition of bacterial toxin activity. In particular, certain catechins have been shown to have bactericidal effects on the oral bacterium, Aggregatibacter actinomycetemcomitans, as well as the ability to inhibit a key virulence factor of this organism, leukotoxin (LtxA). The mechanism of catechin-mediated inhibition of LtxA has not been shown.

METHODS

In this work, we studied the ability of six catechins to inhibit LtxA-mediated cytotoxicity in human white blood cells, using Trypan blue staining, and investigated the mechanism of action using a combination of techniques, including fluorescence and circular dichroism spectroscopy, confocal microscopy, and surface plasmon resonance.

RESULTS

We found that all the catechins except (-)-catechin inhibited the activity of this protein, with the galloylated catechins having the strongest effect. Pre-incubation of the toxin with the catechins increased the inhibitory action, indicating that the catechins act on the protein, rather than the cell. The secondary structure of LtxA was dramatically altered in the presence of catechin, which resulted in an inhibition of toxin binding to cholesterol, an important initial step in the cytotoxic mechanism of the toxin.

CONCLUSIONS

These results demonstrate that the catechins inhibit LtxA activity by altering its structure to prevent interaction with specific molecules present on the host cell surface.

GENERAL SIGNIFICANCE

Galloylated catechins modify protein toxin structure, inhibiting the toxin from binding to the requisite molecules on the host cell surface.

Aggregatibacter actinomycetemcomitans Leukotoxin Is Delivered to Host Cells in an LFA-1-Indepdendent Manner When Associated with Outer Membrane Vesicles

The Gram-negative bacterium, Aggregatibacter actinomycetemcomitans, has been associated with localized aggressive periodontitis (LAP). In particular, highly leukotoxic strains of A. actinomycetemcomitans have been more closely associated with this disease, suggesting that LtxA is a key virulence factor for A. actinomycetemcomitans. LtxA is secreted across both the inner and outer membranes via the Type I secretion system, but has also been found to be enriched within outer membrane vesicles (OMVs), derived from the bacterial outer membrane. We have characterized the association of LtxA with OMVs produced by the highly leukotoxic strain, JP2, and investigated the interaction of these OMVs with host cells to understand how LtxA is delivered to host cells in this OMV-associated form. Our results demonstrated that a significant fraction of the secreted LtxA exists in an OMV-associated form. Furthermore, we have discovered that in this OMV-associated form, the toxin is trafficked to host cells by a cholesterol- and receptor-independent mechanism in contrast to the mechanism by which free LtxA is delivered. Because OMV-associated toxin is trafficked to host cells in an entirely different manner than free toxin, this study highlights the importance of studying both free and OMV-associated forms of LtxA to understand A. actinomycetemcomitans virulence.

Clinical performance of non-surgical periodontal therapy in a large Chinese population with generalized aggressive periodontitis

AIM

This study aimed to evaluate clinical performance of non-surgical periodontal treatment (NSPT) and its influential factors in a large Chinese population with generalized aggressive periodontitis (GAgP).

MATERIAL AND METHODS

Longitudinal periodontal examination data of 1,004 GAgP patients (numbers of patients with observation periods 6 weeks~, 3 months~, 6 months~, 1 year~, 3 years~ and >5 years were 203, 310, 193, 205, 70 and 23, respectively) were extracted from a hospital-based electronic periodontal charting record system and analysed by multilevel analysis.

RESULTS

Mean probing depth (PD) and attachment loss (AL) reductions at patient level were 1.17 mm and 1.07 mm, respectively. Multilevel analysis demonstrated PD reductions after maintenance were mainly influenced by frequency of supportive periodontal treatment (FSPT), gender, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD and bleeding index reductions were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline AL, baseline mobility, tooth type and baseline PD.

CONCLUSION

The clinical performance of NSPT on patients with GAgP was proved in the large Chinese population. Outcomes of NSPT were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD.

Receptor-Based Peptides for Inhibition of Leukotoxin Activity

The Gram-negative bacterium Aggregatibacter actinomycetemcomitans, commonly associated with localized aggressive periodontitis (LAP), secretes an RTX (repeats-in-toxin) protein leukotoxin (LtxA) that targets human white blood cells, an interaction that is driven by its recognition of the lymphocyte function-associated antigen-1 (LFA-1) integrin. In this study, we report on the inhibition of LtxA-LFA-1 binding as an antivirulence strategy to inhibit LtxA-mediated cytotoxicity. Specifically, we designed and synthesized peptides corresponding to the reported LtxA binding domain on LFA-1 and characterized their capability to inhibit LtxA binding to LFA-1 and subsequent cytotoxic activity in human immune cells. We found that several of these peptides, corresponding to sequential β-strands in the LtxA-binding domain of LFA-1, inhibit LtxA activity, demonstrating the effectiveness of this approach. Further investigations into the mechanism by which these peptides inhibit LtxA binding to LFA-1 reveal a correlation between toxin-peptide affinity and LtxA-mediated cytotoxicity, leading to a diminished association between LtxA and LFA-1 on the cell membrane. Our results demonstrate the possibility of using target-based peptides to inhibit LtxA activity, and we expect that a similar approach could be used to hinder the activity of other RTX toxins.

Clinical and microbiological characterization of localized aggressive periodontitis: a cohort study

BACKGROUND

Localized aggressive periodontitis (LAgP) is an infectious periodontal disease which generally affects young people. Recent data suggest the involvement of different bacterial species in different populations. The causative bacterial species in Israel has never been identified despite a high prevalence of LAgP in this population. The objectives of this study were to characterize the bacterial microbiota of periodontal pockets within an Israeli LAgP population who were also clinically assessed.

METHODS

Twenty-one LAgP patients (test) and 12 chronic periodontitis patients (control) were examined. Bacterial samples were collected from periodontal pockets and analysed by both culture and polymerase chain reaction techniques. Mann-Whitney U test and chi-square test were used to compare results between the groups.

RESULTS

Higher levels of Parvimonas micra (>10(6) ), Aggregatibacter actinomycetemcomitans (>10(5) ), Fusobacterium nucleatum/F. periodonticum (>10(6) ), and Tannerella forsythia (levels of 10(5) to 10(6) bacteria) were detected in the LAgP group compared to the control (p < 0.05), while levels of Porphyromonas gingivalis and Prevotella intermedia were higher in the CP group.

CONCLUSIONS

The characteristic periodontal bacterial flora of LAgP patients in Israel is mainly comprised of P. micra, A. actinomycetemcomitans, F. nucleatum/F. periodonticum and T. forsythia. Similar population based studies of each population will improve the quality of treatment of LAgP when individual sampling is not possible.

Non-surgical periodontal therapy with systemic antibiotics in patients with untreated chronic periodontitis: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis is to evaluate the effectiveness of different systemic antibiotics in combination with scaling and root planing (SRP) when compared to SRP alone in patients with untreated chronic periodontitis.

BACKGROUND

Although chronic periodontitis is mostly treated without adjunctive systemic antibiotics, some recent meta-analyses have shown clinical benefit for some systemic antibiotics when used as an adjunct to SRP. However, there is a wide variety of systemic antibiotic regimens used today. It remains unclear if the selected type of systemic antibiotic influences the magnitude of clinical benefit.

MATERIAL AND METHODS

The MEDLINE-PubMed database was searched from their earliest records through May 16, 2013. Several journals were hand searched and some authors were contacted for additional information. Outcome measures analysed were mean bleeding on probing change, mean clinical attachment level gain and mean probing pocket depth reduction. Extracted data were pooled using a random effect model. Weighted mean differences were calculated and heterogeneity was assessed.

RESULTS

The search yielded 281 abstracts. Ultimately, 95 studies were selected, describing 43 studies meeting the eligibility criteria. Systemic antibiotics showed a significant (p < 0.05) additional pocket depth reduction for moderate (at 3 mo 0.27 mm ± 0.09, at 6 mo 0.23 mm ± 0.10 and at 12 mo 0.25 mm ± 0.27) and deep pockets (at 3 mo 0.62 mm ± 0.17, at 6 mo 0.58 mm ± 0.16 and at 12 mo 0.74 mm ± 0.30). Statistically, no specific type of antibiotic was superior over another. However, when analysing the clinical data for initially moderate pockets or deep pockets, some trends became apparent.

CONCLUSION

Systemic antibiotics combined with SRP offer additional clinical improvements compared to SRP alone. Although there were no statistically significant differences, there was a trend that for initially moderate and deep pockets, metronidazole or metronidazole combined with amoxicillin, resulted in clinical improvements that were more pronounced over doxycycline or azithromycin. Additionally, there was a trend that the magnitude of the clinical benefit became smaller over time (1 year).

Pathogenicity of the highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans and its geographic dissemination and role in aggressive periodontitis

For decades, Aggregatibacter actinomycetemcomitans has been associated with aggressive forms of periodontitis in adolescents. In the middle of the 1990s, a specific JP2 clone of A. actinomycetemcomitans, belonging to the cluster of serotype b strains of A. actinomycetemcomitans and having a number of other characteristics, was found to be strongly associated with aggressive forms of periodontitis, particularly in North Africa. Although several longitudinal studies still point to the bacterial species, A. actinomycetemcomitans as a risk factor of aggressive periodontitis, it is now also widely accepted that the highly leukotoxic JP2 clone of A. actinomycetemcomitans is implicated in rapidly progressing forms of aggressive periodontitis. The JP2 clone strains are highly prevalent in human populations living in Northern and Western parts of Africa. These strains are also prevalent in geographically widespread populations that have originated from the Northwest Africa. Only sporadic signs of a dissemination of the JP2 clone strains to non-African populations have been found despite Africans living geographically widespread for hundreds of years. It remains an unanswered question if a particular host tropism exists as a possible explanation for the frequent colonization of the Northwest African population with the JP2 clone. Two exotoxins of A. actinomycetemcomitans are known, leukotoxin (LtxA) and cytolethal distending toxin (Cdt). LtxA is able to kill human immune cells, and Cdt can block cell cycle progression in eukaryotic cells and thus induce cell cycle arrest. Whereas the leukotoxin production is enhanced in JP2 clone strains thus increasing the virulence potential of A. actinomycetemcomitans, it has not been possible so far to demonstrate such a role for Cdt. Lines of evidence have led to the understanding of the highly leukotoxic JP2 clone of A. actinomycetemcomitans as an aetiological factor of aggressive periodontitis. Patients, who are colonized with the JP2 clone, are likely to share this clone with several family members because the clone is transmitted through close contacts. This is a challenge to the clinicians. The patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontal lesions are relatively high. Furthermore, timely periodontal treatment, in some cases including periodontal surgery supplemented by the use of antibiotics, is warranted. Preferably, periodontal attachment loss should be prevented by early detection of the JP2 clone of A. actinomycetemcomitans by microbial diagnostic testing and/or by preventive means.

Treatment of aggressive periodontitis

Despite etiological differences between aggressive and chronic periodontitis, the treatment concept for aggressive periodontitis is largely similar to that for chronic periodontitis. The goal of treatment is to create a clinical condition that is conducive to retaining as many teeth as possible for as long as possible. When a diagnosis has been made and risk factors have been identified, active treatment is commenced. The initial phase of active treatment consists of mechanical debridement, either alone or supplemented with antimicrobial drugs. Scaling and root planing has been shown to be effective in improving clinical indices, but does not always guarantee long-term stability. Antimicrobials can play a significant role in controlling aggressive periodontitis. Few studies have been published on this subject for localized aggressive periodontitis, but generalized aggressive periodontitis has been subject to more scrutiny. Studies have demonstrated that systemic antibiotics as an adjuvant to scaling and root planing are more effective in controlling disease compared with scaling and root planing alone or with supplemental application of local antibiotics or antiseptics. It has also become apparent that antibiotics ought to be administered with, or just after, mechanical debridement. Several studies have shown that regimens of amoxicillin combined with metronidazole or regimens of clindamycin are the most effective and are preferable to regimens containing doxycycline. Azithromycin has been shown to be a valid alternative to the regimen of amoxicillin plus metronidazole. A limited number of studies have been published on surgical treatment in patients with aggressive periodontitis, but the studies available show that the effect can be comparable with the effect on patients with chronic periodontitis, provided that proper oral hygiene is maintained, a strict maintenance program is followed and modifiable risk factors are controlled. Both access surgery and regenerative techniques have shown good results in patients with aggressive periodontitis. Once good periodontal health has been obtained, patients must be enrolled in a strict maintenance program that is directed toward controlling risk factors for disease recurrence and tooth loss. The most significant risk factors are noncompliance with regular maintenance care, smoking, high gingival bleeding index and poor plaque control. There is no evidence to suggest that daily use of antiseptic agents should be part of the supportive periodontal therapy for aggressive periodontitis.

Detection ofTannerella forsythiaand/orPrevotella intermediaMight Be Useful for Microbial Predictive Markers for the Outcome of Initial Periodontal Treatment in Koreans

A proportion of diseased sites in periodontal disease do not respond to the initial treatment, which might be due in part to the presence of specific microbial pathogens. The aim of this study was to clarify the value of microbial screening for predicting the outcome of periodontal treatment in Koreans using a polymerase chain reaction (PCR). This study enrolled 32 adults with periodontal disease. Microbial and clinical examinations were performed at the baseline and after the initial treatment (professional toothbrushing, scaling, and root planing). Subgingival plaque samples were taken from four sites in each subject (total 128 samples). PCR was used to detect the four putative pathogenic bacteria. There was an improvement in the average of each clinical measurement after the initial treatment. However, approximately half of the sites exhibiting bleeding upon probing (BOP) at the baseline still exhibited bleeding after treatment. There was a close association between the presence of BOP and the presence of Tannerella forsythia (formerly Bacteroides forsythus) and/or Prevotella intermedia. Furthermore, the sites harboring both T. forsythia and P. intermedia at the baseline had a poorer response to treatment than the sites where these two species were not detected. Therefore, microbial screening for T. forsythia and P. intermedia might be useful for predicting the treatment outcome in Koreans.

Antibiotic susceptibility of Aggregatibacter actinomycetemcomitans JP2 in a biofilm

BACKGROUND

Localized aggressive periodontitis (LAgP) is an inflammatory disease associated with specific bacteria, particularly Aggregatibacter actinomycetemcomitans, which can result in early tooth loss. The bacteria grow as a biofilm known as subgingival plaque. Treatment includes mechanical debridement of the biofilm, often associated with empirical antibiotic treatment.

OBJECTIVE

The aims of this study were to test in vitro the sensitivity of A. actinomycetemcomitans JP2 during planktonic and biofilm growth to doxycycline and to the combination of metronidazole and amoxicillin, which are two antibiotic protocols commonly used in clinical practice.

DESIGN

Two in vitro biofilm models were used to test the effects of the antibiotics: a static 96-well plate assay was used to investigate the effect of these antibiotics on biofilm formation whilst a flow chamber model was used to examine the effect on established biofilms.

RESULTS

Of the antibiotics tested in this model system, doxycycline was most efficacious with a minimal inhibitory concentration (MIC) against planktonic cells of 0.21 mg/L and minimal biofilm inhibitory concentration (MBIC) of 2.10 mg/L. The most commonly prescribed antibiotic regimen, amoxicillin + metronidazole, was much less effective against both planktonic and biofilm cells with an MIC and MBIC of 12.0 mg/L and 20.2 mg/L, respectively. A single treatment of the clinically achievable concentration of 10 mg/L doxycycline to sparse A. actinomycetemcomitans biofilms in the flow chamber model resulted in significant decreases in biofilm thickness, biovolume, and cell viability. Dense A. actinomycetemcomitans biofilms were significantly more resistant to doxycycline treatment. Low concentrations of antibiotics enhanced biofilm formation.

CONCLUSION

A. actinomycetemcomitans JP2 homotypic biofilms were more susceptible in vitro to doxycycline than amoxicillin + metronidazole.

Aggressive periodontitis: how does an understanding of the pathogenesis affect treatment?

Aggressive periodontitis is a relatively rare periodontal condition that can result in significant attachment loss over a short period of time. As the disease is difficult to manage, owing to its rapid progression and severity, a variety of adjuncts have been advocated in its management. The authors outline concepts of the aetiology and pathogenesis of aggressive periodontitis and how the different treatment regimens relate to the current understanding of the disease process.

CLINICAL RELEVANCE

There is a wide variety of treatment regimens advocated for the treatment of aggressive periodontitis. General dental practitioners and specialists should be aware of the relative advantages and disadvantages of these and how they relate to the disease process.

Antimicrobial therapy in periodontitis: the use of systemic antimicrobials against the subgingival biofilm

OBJECTIVES

The aim was to answer three relevant questions: can systemic antimicrobials be efficacious if the biofilm is not disrupted? Can the type of debridement of the subgingival biofilm impact upon the clinical outcomes of the adjunctive antimicrobial therapy? Is the efficacy of the adjunctive systemic antimicrobial therapy dependent on the quality of the debridement of the subgingival biofilm and the sequence debridement-antibiotic usage?

MATERIAL AND METHODS

Relevant papers were searched, critically analysed and their data were extracted.

RESULTS

For the first question, studies assessing susceptibility of bacteria in biofilms, and clinical studies evaluating systemic antimicrobials as monotherapy, were reviewed. For the second question, clinical studies comparing systemic antimicrobials as adjuncts to non-surgical debridement or to periodontal surgery and clinical trials using systemic antibiotics with periodontal surgery were evaluated. For the third question, a previous systematic review was updated.

CONCLUSION

If systemic antimicrobials are indicated in periodontal therapy, they should be adjunctive to mechanical debridement. There is not enough evidence to support their use with periodontal surgery. Indirect evidence suggests that antibiotic intake should start on the day of debridement completion, debridement should be completed within a short time (preferably <1 week) and with an adequate quality, to optimize the results.

Dental caries and periodontitis: contrasting two infections that have medical implications

Both dental decay and periodontal disease are diagnosable and treatable bacterial infections. They are distinctly different infections, with dental decay occurring on the supragingival surfaces of the teeth and periodontal infections occurring in the gingival tissue approximating the subgingival plaque. The bacteria involved and the pathophysiology of these infections are distinctly different.

Clinical and microbiological effects of different antimicrobials on generalized aggressive periodontitis

AIM

To evaluate and compare the effects of adjunctive metronidazole plus amoxicillin, doxycycline and metronidazole on clinical and microbiological parameters in patients with generalized aggressive periodontitis.

MATERIAL AND METHODS

Forty-three patients participated in this randomized clinical trial divided into four groups. Six weeks after scaling and root planning (SRP), groups 1-3 received adjunctive metronidazole, plus amoxicillin, doxycycline and metronidazole respectively, and group 4 acted as controls. Clinical recordings concerning probing depth, probing attachment level and bleeding on probing were performed at baseline, 6 weeks after SRP and 6 months from baseline. Subgingival samples were analysed using the 'checkerboard' DNA-DNA hybridization for Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Tannerella forsythia and Treponema denticola.

RESULTS

All treatments resulted in improvement of clinical parameters (ANOVA p > 0.05). Systemic administration of metronidazole plus amoxicillin or metronidazole resulted in statistically significant greater reduction of the proportion of sites > 6 mm than SRP (z-test, p < 0.05). These antimicrobials yielded a significant effect on levels of important periodontal pathogens for 6 months.

CONCLUSION

Adjunctive metronidazole plus amoxicillin or metronidazole alone (when A.actinomycetemcomitans is not involved) is effective in deep pockets of aggressive periodontitis patients.

Systemic antibiotics in periodontics

This position paper addresses the role of systemic antibiotics in the treatment of periodontal disease. Topical antibiotic therapy is not discussed here. The paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. The document consists of three sections: 1) concept of antibiotic periodontal therapy; 2) efficacy of antibiotic periodontal therapy; and 3) practical aspects of antibiotic periodontal therapy. The conclusions drawn in this paper represent the position of the American Academy of Periodontology and are intended for the information of the dental profession.

Systemic use of metronidazole in the treatment of chronic periodontitis: a pilot study using clinical, microbiological, and enzymatic evaluation

The aim of the present parallel, double-blind investigation was to evaluate the effect of using systemic metronidazole alone or associated to scaling and root planing on adult chronic periodontal disease, monitored at baseline, 30, 60 and 90 days. Twelve subjects were divided into three groups: the first group (Group I - 22 sites) was submitted to scaling and root planing (SRP) alone; the second group (Group II - 30 sites) received SRP and 250 mg of metronidazole (3 times a day for 10 days), and the third group (Group III - 31 sites) was treated with metronidazole alone. The clinical parameters evaluated were probing depth (PD), clinical attachment level (CAL), plaque index (PlI), gingival index (GI) and bleeding upon probing (BP). Microbiological (BANA test) and enzymatic (Pocket Watch) tests were also performed. All three proposed treatments produced significant improvements in clinical conditions of subjects, from baseline, 30, 60 and 90-day period, except for clinical attachment level. The results obtained by microbiological and enzymatic tests did not show statistical differences among the groups for the 90-day period (r = 0.7924 and r = 0.7757, respectively). In relation to clinical parameters, statistical differences among groups were observed only for the gingival index (p = 0.0261) between Groups I and II, and probing depth (p = 0.0124) between Group I and the others. We conclude that the use of systemic metronidazole did not produce additional effects on the microbiological conditions of these patients with chronic periodontal disease.

Non-surgical approach to advanced chronic periodontitis: a 17.5-year case report

This 17.5-year longitudinal case report details the treatment of advanced chronic periodontitis in a female patient commencing at 34 years of age. The woman was provided with periodontal care comprising of temporary fixation, scaling and root planing, intra-pocket irrigation using a root canal syringe and regular supervised maintenance. The patient presented with a 10-year history of bleeding gums. Therapy conducted in general practice had included simple curettage and irrigation. However, these treatments proved unsuccessful and the patient often changed dentists seeking better treatment. She presented to the University Dental Hospital, for diagnosis and treatment of her periodontal conditions after her mandibular lateral incisor had exfoliated. On presentation a purulent exudate could be expressed from all of the pockets. All anterior teeth, excluding the maxillary canines, demonstrated +2 to +3 mobility. The patient did not want any surgical treatment or her teeth extracted. It was decided to treat the patient conservatively without surgery. By postponing extraction, the authors were in a better position to determine the prognosis of the remaining teeth after the infection was under control. Although six teeth were extracted during the 17.5 years, this case report suggests that a non-surgical approach is a viable option while maintaining regular visits for periodontal care.

Position paper: periodontal diseases of children and adolescents

Children and adolescents are subject to several periodontal diseases. Although there is a much lower prevalence of destructive periodontal diseases in children than in adults, children can develop severe forms of periodontitis. In some cases, this destructive disease is a manifestation of a known underlying systemic disease. In other young patients, the underlying cause for increased susceptibility and early onset of disease is unknown. These diseases are often familial, suggesting a genetic predisposition for aggressive disease. Current modalities for managing periodontal diseases of children and adolescents may include antibiotic therapy in combination with non-surgical and/or surgical therapy. Since early diagnosis ensures the greatest chance for successful treatment, it is important that children receive a periodontal examination as part of their routine dental visits.

Topical and systemic antibiotics in the management of periodontal diseases

Both systemic and topical antibiotics are increasingly used in the management of periodontal infections. Whilst these drugs are used mostly on an empirical basis, some contend that rational use of antibiotics should be the norm due to their wide abuse and consequential global emergence of antibiotic resistance organisms. Here we review the rationale and principles of antimicrobial therapy, treatment goals, drug delivery routes and various antibiotics that are used in the management of periodontal diseases. The pros and cons of systemic and local antibiotic therapy are described together with practical guidelines for their delivery. The available data indicate, in general, that mechanical periodontal treatment alone is adequate to ameliorate or resolve the clinical condition in most cases, but adjunctive antimicrobial agents, delivered either locally or systemically, can enhance the effect of therapy in specific situations. This is particularly true for aggressive (early onset) periodontitis, in patients with generalised systemic disease that may affect host resistance and in case of poor response to conventional mechanical therapy. Locally delivered antibiotics together with mechanical debridement are indicated for non-responding sites of focal infection or in localised recurrent disease. After resolution of the periodontal infection, the patient should be placed on an individually tailored maintenance care programme. Optimal plaque control by the patient is of paramount importance for a favourable clinical and microbiological response to any form of periodontal therapy.

Detection of a highly toxic clone of Actinobacillus actinomycetemcomitans (JP2) in a Moroccan immigrant family with multiple cases of localized aggressive periodontitis

The JP2 clone of Actinobacillus actinomycetemcomitans, a high-leukotoxin-producing strain, characterized by a 530-basepair (bp) deletion in the promoter region of the leukotoxin gene operon and mainly found among individuals with African origin, is associated with localized aggressive periodontitis. The objective of the study was to examine the occurrence of periodontal disease in a Moroccan immigrant family living in Denmark in which the oldest son (14 year) was referred and treated for localized aggressive periodontitis. Further, the potential occurrence of the JP2 clone of A. actinomycetemcomitans in the family was examined. Here we present the clinical, radiographic, and microbiological findings from the family. Clinical and radiographic examination of the other family members revealed that 3 of 5 younger siblings had localized aggressive periodontitis, one had gingivitis and the mother had chronic periodontitis. Despite scaling followed by intensive maintenance therapy several family members, including the sibling with gingivitis, had further attachment loss at the 1-year examination. The JP2 clone of A. actinomycetemcomitans was isolated from subgingival plaque samples from 4 children with periodontitis. In contrast, it was not detected in plaque from the oldest boy, who had been treated for localized aggressive periodontitis by surgery combined with antibiotic therapy. The 4 children with periodontitis and colonized with the JP2 clone were treated by scaling and antibiotic administration. One month later the JP2 clone could still be detected in plaque samples. In conclusion, it is confirmed that members of immigrant families with African origin are potential carriers of the JP2 clone and that those families often have multiple family members with localized aggressive periodontitis. It is proposed that those families are given periodontal examination frequently to benefit from early diagnosis and treatment of the disease.

Systemic antimicrobials in the treatment of chronic periodontal diseases: a dilemma

The use of systemic antimicrobials in the treatment of acute and chronic periodontal diseases must be viewed as a dilemma. On the one hand, the approach is attractive because of the microbial nature of periodontal diseases but, on the other hand, evidence of benefit of these agents is equivocal for the majority of periodontal diseases and antimicrobials have the potential to cause harm. The disadvantages of systemic antimicrobials can be grouped under the headings of allergic reactions, superinfection, toxicity, drug interactions, patient compliance and, perhaps of most widespread importance, bacterial resistance. Mechanical debridement methods, including drainage of pus for acute periodontal abscesses, should be considered the first line treatment for most periodontal diseases. Systemic antimicrobials should be considered as adjuncts to mechanical debridement methods and, in chronic disease, never used alone as they can predispose to abscess formation. Adjunctive systemic antimicrobials may be considered in acute disease where debridement or drainage of pus is difficult, where there is local spread or systemic upset. In chronic periodontal diseases, adjunctive antimicrobials should be considered in early onset or rapidly progressive disease or in advanced chronic adult disease where mechanical therapies have failed or surgery is not a preferred option. Inadequate oral hygiene and tobacco smoking are contraindications to the use of antimicrobials. The value of systemic antimicrobials, where other systemic risk factors co-exist, has still to be established. The role of microbial diagnosis and sensitivity testing for antimicrobial selection at this time must be questioned.

Antimicrobials for the treatment of aggressive periodontitis

Aggressive periodontitis is characterized by a considerable attachment loss over a relatively short period of time. It may be the consequence of either the presence of highly aggressive pathogens or a highly susceptible host. In the first case, the use of antimicrobials should be beneficial in the treatment of those patients. However, due to the organization of the micro-organisms as a biofilm, the increasing incidence of allergies and resistance against antimicrobials and their side-effects, there is still controversy about their benefit in the treatment of periodontal disease. This paper discusses indications for the use of antimicrobials, the substances prescribed and the type of application under the conditions of aggressive periodontitis.

Clinical Responses to Mechanical Periodontal Treatment in Chinese Chronic Periodontitis Patients with and withoutActinobacillus actinomycetemcomitans

BACKGROUND

The purpose of this study was to compare 12-month clinical responses to mechanical periodontal treatment in Chinese chronic periodontitis patients at sites with and without Actinobacillus actinomycetemcomitans at baseline, and to investigate the ability of mechanical periodontal treatment to eliminate A. actinomycetemcomitans.

METHODS

Nineteen patients and a total of 76 selected sites with a mean probing depth (PD) of > or = 7 mm were studied. Whole mouth presence or absence of supragingival plaque (PI%), bleeding on probing (BOP%), probing depth (PD), and probing attachment level (PAL) were recorded at six sites per tooth at baseline and after 3, 9, and 12 months. Baseline subgingival plaque samples were taken from the deepest PD site in each quadrant using sterile paper points and were cultured on TSBV plates for 5 days in a 5% CO2-air incubator. All sites received mechanical periodontal treatment, which included oral hygiene instructions and supragingival and subgingival instrumentation with or without surgical access, with maintenance care being provided once every 3 months thereafter.

RESULTS

At baseline, A. actinomycetemcomitans was isolated in 13 of the 19 subjects (68%) and in 29 out of the 76 sampled sites (38%). At the end of 12 months, in three of the initially A. actinomycetemcomitans-positive subjects, A. actinomycetemcomitans was not detected in the sampled sites, while one subject, in whom A. actinomycetemcomitans was not initially found at the sampled sites was A. actinomycetemcomitans-positive at 12 months. Multi-level variance component models showed there was no statistically significant difference in all clinical parameters between A. actinomycetemcomitans-positive and -negative subjects (P > 0.05). In the sampled sites of the initially A. actinomycetemcomitans-positive subjects, the mean PD was reduced from 7.6 +/- 1.6 mm to 3.2 +/- 1.8 mm, the mean PAL gain was 1.4 +/- 2.0 mm, and the mean recession was 3.0 +/- 2.3 mm. The corresponding figures in the sampled sites of the initially A. actinomycetemcomitans-negative subjects were 7.5 +/- 1.6 mm to 2.7 +/- 1.0 mm, 2.3 +/- 2.6 mm and 2.4 +/- 2.2 mm for mean PD changes, PAL gain, and mean recession, respectively.

CONCLUSIONS

Favorable clinical responses to mechanical periodontal therapy may occur in Chinese chronic periodontitis patients at sites infected with A. actinomycetemcomitans. The mere detection of subgignival A. actinomycetemcomitans does not necessarily imply poorer treatment outcomes in the control of chronic periodontitis.

A systematic review on the effect of systemic antimicrobials as an adjunct to scaling and root planing in periodontitis patients

BACKGROUND

Scaling and root planing (SRP) are the bases of non-surgical therapy in the treatment of periodontitis. However, results from this therapy are often unpredictable and dependable from many different factors.

OBJECTIVES

The aim of this systematic review was to evaluate the effectiveness of the adjunctive use of systemic antimicrobials with scaling and root planing (SRP) vs. SRP alone in the treatment of chronic (CP) or aggressive periodontitis (AgP).

SEARCH STRATEGY

Use of computerized databases, namely MEDLINE, the Cochrane Oral Health Group Specialty Trials Register and EMBASE; reference lists from relevant articles were hand-searched; and a hand-search of selected journals until April 2001.

SELECTION CRITERIA

Studies were selected if they were designed as controlled clinical trials in which systemically healthy patients with either AgP or CP were treated with SRP plus systemic antimicrobials in comparison with SRP alone or with placebo, for a minimum of 6 months. Main outcome measures were clinical attachment level (CAL) change and probing pocket depth (PPD) change.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted independently information regarding quality and study characteristics, in duplicate. Kappa scores determined their agreement. Main results were collected and grouped by drug, disease and PPD category. For the quantitative data synthesis, the data was pooled (when mean differences and standard errors were available), and either a Fixed Effects or Random Effects meta-analysis was used for the analysis.

RESULTS

After an initial selection, 158 papers were identified by the manual and electronic searches; 25 papers were eligible for inclusion. Their quality assessment showed that randomization and allocation concealment methods were seldom reported and blindness was usually not defined clearly. In general, selected studies showed high variability and lack of relevant information for an adequate assessment. Overall, SRP plus systemic antimicrobial groups demonstrated better results in CAL and PPD change than SRP alone or with placebo groups. Only limited meta-analyses could be performed, due to the difficulties in pooling the studies and the lack of appropriate data. This analysis showed a statistically significant additional benefit for spiramycin (PPD change) and amoxicillin/metronidazole (CAL change) in deep pockets.

CONCLUSION

Systemic antimicrobials in conjunction with SRP, can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of CAL and PPD change, and reduced risk of additional CAL loss. However, differences in study methodology and lack of data precluded an adequate and complete pooling of data for a more comprehensive analyses. It was difficult to establish definitive conclusions, although patients with deep pockets, progressive or 'active' disease, or specific microbiological profile, can benefit more from this adjunctive therapy.

Rationale for use of antibiotics in periodontics

The purpose of this review is to provide the clinician with some practical rationale for the selection and use of antibiotics in the treatment of destructive periodontal diseases. We have attempted to integrate approximately 20 years of periodontal literature describing antibiotic therapy with personal experience and 21st century ideas. This article addresses antibiotic use during treatment of aggressive periodontitis with emphasis on juvenile disease and adult refractory diseases. The literature review revealed few large, controlled studies that compared efficacy of adjunctive antibiotic use to mechanical therapy alone. Even fewer studies evaluated the efficacy of one antibiotic relative to another. However, based on the evidence available, certain conclusions were drawn. Adjunctive use of an antibiotic along with mechanical debridement is recommended for the treatment of Actinobacillus actinomycetemcomitans-associated periodontitis as an acceptable therapeutic regimen. Due to the emergence of tetracycline-resistant A. actinomycetemcomitans, the combination of metronidazole and amoxicillin may be preferable. In aggressive refractory periodontitis, compelling evidence exists that the use of an appropriate adjunctive antibiotic frequently gives a more favorable clinical response than mechanical therapy alone. Unfortunately, the selection of antibiotic is not as clear and is probably case-dependent. Positive responses have been reported with amoxicillin/clavulanic acid, clindamycin, metronidazole, and the combination therapy metronidazole plus amoxicillin. The introduction of local delivery antibiotics specifically for the treatment of periodontitis offers a novel concept for the treatment of localized disease. The latter, in particular, may prove useful in the treatment of recurrent disease activity or where only a few individual sites are involved.

In vitro antimicrobial susceptibility of oral strains of Actinobacillus actinomycetemcomitans to seven antibiotics

BACKGROUND/AIMS

Periodontal infections with Actinobacillus actinomycetemcomitans seem to be refractory to conventional therapy. The aim of the present study was to test the in vitro susceptibilities of A. actinomycetemcomitans strains to a panel of seven orally administrable antibiotics.

METHODS

A total of 60 isolates of A. actinomycetemcomitans recovered from 43 individuals with gingivitis or periodontitis were tested. In addition, laboratory strains UP-6 and JP2 were analysed. The E-test was employed in order to determine minimal inhibitory concentrations (MIC) of antibiotics ampicillin/sulbactam, roxithromycin, azithromycin, doxycycline, metronidazole, ciprofloxacin, and moxifloxacin.

RESULTS

A. actinomycetemcomitans was highly susceptible to both fluoro-quinolones (MIC90 of 0.006 microgram/mL of ciprofloxacin and 0.032 microgram/mL of moxifloxacin). Good susceptibilities were found for ampicillin/sulbactam and doxycycline (MIC90 of 0.75 microgram/mL and 1 microgram/mL, respectively), and moderate susceptibilities for azithromycin (MIC90 of 3 microgram/mL). Most strains were resistant to metronidazole and roxithromycin. Cluster analysis revealed two larger clusters of A. actinomycetemcomitans strains with the smaller cluster assembling isolates with significantly higher MICs of most antibiotics.

CONCLUSIONS

Due to reported favourable pharmacokinetics, the fluoro-quinolone moxifloxacin appeared to be a promising candidate for adjunctive systemic antibiotic therapy in periodontal infections with A. actinomycetemcomitans.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

A 2-step non-surgical procedure and systemic antibiotics in the treatment of rapidly progressive periodontitis

BACKGROUND

In the last few years knowledge about periodontal infections has increased enormously, nevertheless practitioners are still seeking guidelines for suitable treatment concepts.

METHODS

The aim of this study was to examine the effect of doxycycline, metronidazole, and clindamycin used adjunctively in a 2-step nonsurgical procedure in patients with rapidly progressive periodontitis (RPP). The first step included scaling, root planing, and polishing (SRP) in each quadrant using 4 to 5 visits. The second step included full-mouth enhanced root planing (RP) and wound dressing in 1 or 2 visits after SRP and the beginning of antibiotic therapy. Forty-eight patients (mean age 32.4 years) with generalized RPP, with an average of 16 sites with probing depths (PD) deeper than 8 mm, and high counts of Porphyromonas gingivalis were randomly assigned to 4 different groups: group 1 (doxycycline) n = 12, group 2 (metronidazole) n = 15, group 3 (clindamycin) n = 11, and group 4 (control group; no antibiotic treatment) n = 10. Clinical evaluations, including plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), clinical attachment level (CAL), and bacteriological and crevicular cell sampling, were done at baseline (BL), 3 weeks after SRP, and 6 and 24 months after RP.

RESULTS

After the first step (SRP), we observed an improvement of PI and SBI in all 4 groups, but did not see any statistically significant PD reduction 3 weeks after SRP compared to baseline. However, 6 and 24 months after the second step (RP) we observed a significantly greater reduction of PD in groups 2 and 3 and a significantly greater CAL gain in comparison to groups 1 and 4. After 24 months, the attachment level gain in group 1 and group 4 was less than 1.5 mm, and less than 1.0 mm in PD site categories 6 to 9 mm and >9 mm. PI showed no significant difference between the groups throughout the period after SRP until 24 months, compared to 3 weeks after SRP. SBI decreased most in the metronidazole and clindamycin groups. P. gingivalis and Actinobacillus actinomycetemcomitans were almost completely eradicated in these 2 groups 24 months after RP. In addition, the phagocytotic capacity of crevicular polymorphonuclear neutrophils was increased in groups 2 and 3 after the second step.

CONCLUSIONS

The present results show that metronidazole and clindamycin are effective antibiotics when used adjunctively in a 2-step nonsurgical procedure of scaling and root planing in RPP patients.