Combined antibiotic (metronidazole) and mechanical treatment effects on the subgingival bacterial flora of sites with recurrent periodontal disease

Self-Propelled PLGA Micromotor with Chemotactic Response to Inflammation

Local drug delivery systems have recently been developed for multiple diseases that have the requirements of site-specific actions, prolonged delivery periods, and decreased drug dosage to reduce undesirable side effects. The challenge for such systems is to achieve directional and precise delivery in inaccessible narrow lesions, such as periodontal pockets or root canals in deeper portions of the dentinal tubules. The primary strategy to tackle this challenge is fabricating a smart tracking delivery system. Here, drug-loaded biodegradable micromotors showing self-propelled directional movement along a hydrogen peroxide concentration gradient produced by phorbol esters-stimulated macrophages are reported. The drug-loaded poly(lactic-co-glycolic acid) micromotors with asymmetric coverage of enzyme (patch-like enzyme distribution) are prepared by electrospraying and postfunctionalized with catalase via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide coupling. Doxycycline, a common drug for the treatment of periodontal disease, is selected as a model drug, and the release study by high-performance liquid chromatography is shown that both the postfunctionalization step and the presence of hydrogen peroxide have no negative influence on drug release profiles. The movement behavior in the presence of hydrogen peroxide is confirmed by nanoparticle tracking analysis. An in vitro model is designed and confirmed the response efficiency and directional control of the micromotors toward phorbol esters-stimulated macrophages.

Systemic anti-microbial agents used in periodontal therapy

Periodontitis is an infectious disease with marked inflammatory response, leading to destruction of underlying tissues. The aim of periodontal therapy is to eradicate the pathogens associated with the disease and attain periodontal health. This is achieved by non-surgical and surgical therapy; however, mechanical debridement and topical application of antiseptics may not be helpful in all cases. In such cases, adjunctive systemic antibiotic therapy remains the treatment of choice. It can reach micro-organisms at the base of the deep periodontal pockets and furcation areas via serum, and also affect organisms residing within gingival epithelium and connective tissue. Before advising any anti-microbial agent, it is necessary to have knowledge of that agent. The aim of this review article is to provide basic details of each systemic anti-microbial agent used in periodontal therapy. The points discussed are its mode of action, susceptible periodontal pathogens, dosage, its use in treatment of periodontal disease, and mechanism of bacterial resistance to each anti-microbial agent. It might be of some help while prescribing these drugs.

Microparticles containing propolis and metronidazole: in vitro characterization, release study and antimicrobial activity against periodontal pathogens

Ethylcellulose microparticles containing metronidazole and propolis extractive solution were prepared and evaluated in vitro against periodontal pathogens. Scanning electron microscopy, particle size analysis, drug entrapment efficiency and drug release of microparticles were determined. The antimicrobial activity of microparticles was evaluated against microorganisms of periodontal importance (Enterococcus faecalis, Streptococcus pyogenes, Streptococcus mutans, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli). It was obtained particles with regular morphology, mean diameter of 1.23 µm, and entrapment efficiency for propolis and metronidazole were 91.41% and 22.23%, respectively. In vitro release studies of propolis and metronidazole from microparticles showed prolonged drug release and controlled by Fickian diffusion. Both propolis and metronidazole displayed activity against the tested strains. Moreover, the results showed that the strains of E. faecalis, S. pyogenes and S. mutans were more susceptible to the propolis and E. faecalis to the metronidazole. It was also observed that the amount of metronidazole to inhibit the microorganism strains in the physical mixture with propolis was smaller than in the metronidazole alone, suggesting potentiation effect between propolis and metronidazole. These microparticles would be useful for developing intermediary or eventual dosage form to be administered into the periodontal pocket more easily and safely.

Chitosan inserts for periodontitis: influence of drug loading, plasticizer and crosslinking on in vitro metronidazole release

Chitosan based metronidazole (MZ) inserts were fabricated by the casting method and characterized with respect to mass and thickness uniformity, metronidazole loading and in vitro metronidazole release kinetics. The fabricated inserts exhibited satisfactory physical characteristics. The mass of inserts was in the range of 5.63 +/- 0.42 to 6.04 +/- 0.89 mg. The thickness ranged from 0.46 +/- 0.06 to 0.49 +/- 0.08 mm. Metronidazole loading was in the range of 0.98 +/- 0.09 to 1.07 +/- 0.07 mg except for batch CM3 with MZ loading of 2.01 +/- 0.08 mg. The inserts exhibited an initial burst release at the end of 24 h, irrespective of the drug to polymer ratio, plasticizer content or cross-linking. However, further drug release was sustained over the next 6 days. Cross-linking with 10% (m/m) of glutaraldehyde inhibited the burst release by approximately 30% and increased the mean dissolution time (MDT) from 0.67 to 8.59 days. The decrease in drug release was a result of reduced permeability of chitosan due to cross-linking.

Effect of a Controlled-Release Chlorhexidine Chip on Clinical and Microbiological Parameters and Prostaglandin E2Levels in Gingival Crevicular Fluid

BACKGROUND

The aim of the present study was to determine the effect of a chlorhexidine chip on crevicular prostaglandin E2 (PGE2) levels and on the clinical and microbiological parameters of periodontitis when used as adjunctive therapy to scaling and root planing (SRP) in patients with chronic periodontitis.

METHODS

This randomized single-blind study was carried out in parallel design. The test group received SRP plus chlorhexidine chip, whereas the control group received SRP alone. Thirty-four subjects, aged 20 to 55 years, with chronic periodontitis were recruited. Clinical indices, microbiological samples, and gingival crevicular fluid (GCF) samples were evaluated at baseline and after 1, 3, and 6 months. Microbiological samples were evaluated under a light microscope. GCF PGE2 levels were determined using radioimmunoassay.

RESULTS

Significant improvements could be found for all clinical variables in both groups over the study period. The mean changes in probing depth obtained by SRP plus chlorhexidine chip were greater than those obtained by the SRP alone group at 3 and 6 months. In the test group, there was also significant gain in clinical attachment level at 6 months. When data were combined from all groups, significant reductions in GCF PGE2 levels and number of microorganisms were noted at all time points. However, in the test group, reduction was greater at 6 months for crevicular PGE2 level and at 3 and 6 months for proportions of spirochetes.

CONCLUSION

Based on the findings of this study, the chlorhexidine chip reduced GCF PGE2 levels and had positive effects on clinical parameters and subgingival flora when used as adjunctive therapy to SRP in patients with chronic periodontitis.

In vitro studies on controlled-release cellulose acetate films for local delivery of chlorhexidine, indomethacin, and meloxicam

BACKGROUND

Delivery of medications into periodontal pockets to suppress or eradicate the pathogenic microbiota or modulate the inflammatory response, thereby limiting periodontal tissue destruction, has attracted significant interest with the purpose of effective periodontal treatment. However, no study has previously attempted to develop a controlled-release formulation of anti-inflammatory agents to be used in the field of periodontology. The aim of the present study was to examine the in vitro release profile of chlorhexidine gluconate, indomethacin, and meloxicam from cellulose acetate films.

METHODS

Cellulose acetate films containing chlorhexidine gluconate, indomethacin, and meloxicam were prepared and cut in a form to fit to the periodontal pocket anatomy. The release of active agents was studied in 10 ml artificial saliva at 37 degrees C. Apparatus Vibrax was used at 150 r.p.m. Determinations were carried out spectrophotometrically and the release profiles were plotted as a function of time.

RESULTS

The formulations showed two different release patterns for a total observation period of approximately 120 h. When the formulations of the three active agents were compared, the release patterns of meloxicam and chlorhexidine gluconate were found to be similar, while the indomethacin-containing formulation exhibited the fastest release rate.

CONCLUSIONS

As a conclusion, cellulose acetate may be a suitable inert material for obtaining a prolonged local release of various anti-inflammatory agents like meloxicam. Further in vitro and in vivo studies are required before starting clinical applications of these controlled-release formulations of anti-inflammatory agents.

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.

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.

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.

Change of antibiotic susceptibility following periodontal therapy. A pilot study in aggressive periodontal disease

BACKGROUND

The hypothesis was tested that bacterial susceptibilities in aggressive periodontitis change upon administration of systemic antibiotics as adjuncts to periodontal therapy.

METHODS

In 23 subjects (average age 38.9+/-6.7 years) with aggressive periodontitis, microbial parameters were assessed prior to and 1 year after completion of comprehensive mechanical/surgical and systemic antimicrobial therapy. Following identification of five selected pathogens with the Rapid ID 32 A system, their susceptibilities towards amoxicillin/clavulanate potassium, metronidazole, and tetracycline were examined with the E-test. Antibiotics were administered according to the test results, and the minimal inhibitory concentrations (MIC90) were reevaluated after 1 year. Statistical analysis was performed on a patient basis, with the site data used for evaluation of the MIC levels.

RESULTS

Bacterial MIC levels remained constant among the three antibiotic treatment groups compared with baseline. Mean MIC90 values ranged from <0.02 to 0.11 microg/ml (amoxicillin/clavulanate potassium), <0.02 to 0.27 microg/ml (metronidazole), and <0.02 to 0.11 microg/ml (tetracycline). Observed changes in susceptibility were attributed to the elimination of single bacterial taxa in the subgingival environment after antibiotic therapy. There were no statistically significant differences in clinical parameters among the treatment groups. Single tetracycline MICs were 1.5- to 6-fold enhanced compared to amoxicillin/clavulanate potassium and metronidazole.

CONCLUSION

The periodontal pathogens investigated prior to and 1 year after periodontal therapy are tested sensitive to the antimicrobial agents. In aggressive periodontitis, changes in bacterial susceptibility upon the administration of systemic antibiotics are associated with the limited number of isolates tested following therapy.

The effect of systemic antibiotics in the treatment of patients with recurrent periodontitis

BACKGROUND

Subjects with periodontal disease exist who either (i) respond poorly to initial mechanical therapy ("refractory" periodontitis) or (ii) fail to adopt adequate self-performed plaque control techniques and hence develop recurrent disease ("recurrent" periodontitis) at multiple sites during the supportive treatment phase (SPT). Various systemic antibiotic regimens have been tried as adjuncts to the mechanical (re-) treatment of such "difficult to treat"-patients. While most studies indicated a positive outcome of the adjunctive therapy, some clinical investigators reported that this additional measure provided little or no benefit.

AIM

The aim of the present investigation was to study the more long term effect of adjunctive antibiotic therapy in the re-treatment of patients with a well defined history of recurrent periodontitis.

MATERIAL AND METHODS

17 subjects with recurrent advanced periodontal disease were, following a baseline examination, subjected to non-surgical therapy including the use of systemic antibiotics (amoxicillin and metronidazole). They were placed in a careful SPT program and re-examined after 1, 3 and 5 years. The examinations included both clinical and microbiological assessments.

RESULTS

It was demonstrated that in subjects with advanced and recurrent periodontitis, re-treatment including (i) comprehensive scaling and root planing (SRP), (ii) systemic administration of antibiotics and (iii) meticulous supragingival plaque control by both mechanical and chemical means established periodontal conditions that in the short term (3 years) and in the majority of subjects could be properly maintained by traditional SPT measures. Between 3 and 5 years, however, only 5 of the 17 subjects exhibited stable periodontal attachment levels.

CONCLUSIONS

Some deep pockets and furcations were most likely inadequately instrumented during the active treatment phase. Microorganisms residing in biofilms left in such locations were probably not sufficiently affected by the 2 weeks of adjunctive antibiotic therapy. It is suggested that removal of certain subgingival deposits, therefore, may require surgical intervention.

Effect of the enamel matrix derivative Emdogain on the growth of periodontal pathogens in vitro

OBJECTIVES

The aim of this study was to evaluate the effect of Emdogain (EMD), used for periodontal regeneration, on the growth of periodontal pathogens like Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. For comparison, we studied the effect of EMD on several microbes associated with other oral diseases as well as its effect on non-pathogenic oral inhabitants.

METHODS

Freshly prepared EMD or its vehicle propylene glycol alginate (PGA) alone were added to calibrated suspensions of microbes. As a control, imitating the post-surgical subgingival situation after flap closure, a serum/NaCl-solution mixture was used. Aliquots for growth assays were taken at scheduled times for calculation of colony-forming units and cell densities over an observation period of 24 h. Additionally, EMD was spotted onto selected, newly seeded microbes growing on agar plates to see if growth inhibition zones could be produced.

RESULTS

The study revealed a marked inhibitory effect of EMD on the growth of the gram-negative periodontal pathogens. A. actinomycetemcomitans showed a significant decrease (p=0.012) in viable counts after 24 h when EMD was added at baseline. P. gingivalis and P. intermedia also showed a marked growth reduction in the presence of EMD and in these cultures no viable microbes could be detected anymore after 24 h. In contrast, no significant growth inhibition was observed in gram-positive bacteria.

CONCLUSIONS

The results suggest that EMD has a positive effect on the composition of bacterial species in the post-surgical periodontal wound, by selectively restricting growth of periopathogens that could hamper the wound healing and reduce the outcome of regenerative procedures.

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.

The clinical and microbiological effects of systemic ornidazole in sites with and without subgingival debridement in early-onset periodontitis patients

BACKGROUND

The purpose of this study was to evaluate the clinical and microbiological effects of systemic ornidazole (ORN) in sites with or without subgingival debridement in early-onset periodontitis (EOP) patients.

METHODS

Two pooled bacterial samples consisting of 4 sites each (scaled and non-scaled sites) were obtained from 30 individuals exhibiting EOP. All patients received oral hygiene instruction (OHI), supragingival scaling and ORN. Subgingival scaling and root planing (SRP) was carried out only in scaled sites. Bacterial samples were taken at baseline (BL) and 1 week and 2, 6, and 12 months after systemic ornidazole administration (500 mg/bid for 7 days). One more sample was taken at scaled sites, one week after SRP.

RESULTS

One week following SRP (scaled sites) Gram-negative facultative and anaerobic rods were significantly reduced while Gram-positive facultative cocci were significantly increased. After ORN administration, P. gingivalis, P. denticola, P. intermedia, B. forsythus, C. rectus, and S. sputigena were no longer detectable in either scaled or non-scaled sites. A statistically significant long-term (2, 6, and 12 months) reduction of P. gingivalis, P. intermedia, P. loescheii, B. forsythus, and C. rectus and a pronounced increase of S. milleri, S. oralis, and S. sanguis counts in both scaled and non-scaled sites were detected in comparison to baseline. A sustained reduction of bleeding tendency and of probing depth was also observed in both scaled and non-scaled sites.

CONCLUSIONS

ORN combined with SRP effects beneficial shifts in the bacterial population associated with substantial clinical improvement, thereby indicating that ORN is effective adjunct in the treatment of EOP deep periodontal pockets where anaerobic bacteria are predominant.

The antimicrobial treatment of periodontal disease: changing the treatment paradigm

Over the last 100 years, methods of surgical periodontal treatment have enjoyed a history of success in improving oral health. The paradigm of care is based on the "non-specific plaque hypothesis"--that is, the overgrowth of bacterial plaques cause periodontal disease, and the suppression of this overgrowth reduces disease risk. The central feature of this approach to care is the removal of inflamed gingival tissue around the teeth to reduce periodontal pocket depth, thereby facilitating plaque removal by the dentist and by the patient at home. Over the last 30 years, with the recognition that periodontal disease(s) is caused by specific bacteria and that specific antimicrobial agents can reduce or eliminate the infection, a second paradigm has developed. This new paradigm, the "specific plaque hypothesis", focuses on reducing the specific bacteria that cause periodontal attachment loss. The contrast between the two paradigms can be succinctly stated as follows: The antimicrobial therapy reduces the cause, while the surgical therapy reduces the result of the periodontal infection. The specific plaque hypothesis has two important implications. First, with the increasing attention to evidence-based models for prevention, treatment, outcome assessment, and reimbursement of care, increasing attention and financial effort will be channeled into effective preventive and treatment methods. Second, the recent observations that periodontal infections increase the risk of specific systemic health problems, such as cardiovascular disease, argue for the prevention and elimination of these periodontal infections. This review highlights some of the evidence for the specific plaque hypothesis, and the questions that should be addressed if antimicrobial agents are to be used responsively and effectively.

Repeated metronidazole and amoxicillin treatment of periodontitis. A follow-up study

BACKGROUND

The prevailing concept is that little or no clear benefit is derived from antibiotic therapy in chronic periodontitis. Studies to determine the effect of metronidazole plus amoxicillin (M+A) on adult periodontitis are questionable because standard design for clinical trials was usually not used. In addition, there is no information about the effect of M+A as the sole therapy for periodontitis.

METHODS

A randomized, triple-blind, controlled clinical trial was used to determine the effect of systemic administration of M+A, as the sole therapy, in progressive adult periodontitis. Forty-six subjects with moderate to advanced adult periodontitis who showed > or =2 mm attachment loss in at least 2 sites in the previous 2 months were entered in the study. Subjects were randomly distributed to a group who received 21 tablets of metronidazole 250 mg plus amoxicillin 500 mg, or to a group receiving a placebo (1 tablet every 8 hours for 1 week). Patients were examined every 2 months for 12 months. The M+A or placebo regimen was repeated at 4 and 8 months. No effort was made to change the oral habits of patients and they received no additional therapy. Differences between groups were assessed using the Mann-Whitney U test. The differences at every 2-month interval within each group were assessed using the ANOVA test.

RESULTS

Seven subjects abandoned the study; at 12 months the M+A group had 20 subjects and the placebo group 19. There were no significant differences in the clinical parameters at baseline between the 2 groups. After 2 months and thereafter, the M+A group showed significant clinical improvement while the placebo group showed a progressive deterioration of periodontal status. At 12 months compared to baseline, subjects of the M+A group showed: 1) a significant overall mean attachment gain of 0.43 mm (P = 0.005); 2) a significant decrease of active sites (P< or =0.03); 3) a significant increase of sites gaining attachment level (P< or =0.01); 4) a significant reduction of pocket depth (P< or =0.00006); and 5) a significant decrease in percentage of bleeding on probing sites (BOP) (P< or =0.0005). Significant differences between both groups at all 2-month evaluations were found in overall mean attachment level (P < or =0.000004), in percent of active sites (P< or =0.03), and in percent of BOP sites (P< or =0.02). Sites exhibiting > or =2 mm of attachment loss in 2 successive or alternate evaluations, and periodontal abscess were noticed only in the placebo group.

CONCLUSIONS

A 1-week course of systemic M+A every 4 months, as the only therapy, arrests the progression of adult periodontitis and significantly improves the clinical parameters of the disease.

Effects of metronidazole plus amoxicillin in progressive untreated adult periodontitis: results of a single 1-week course after 2 and 4 months

A randomized, double-blind, clinical study was done to assess the microbiological and clinical effects of metronidazole plus amoxicillin (M+A) as the only therapy in 46 patients with moderate to advanced progressive adult periodontitis. Patients were included in the study after at least 2 sites showed > or =2 mm clinical attachment loss. Bleeding on probing, probing depth, and clinical attachment level were measured using on automated probe. The percentage of surfaces with plaque was recorded at day 0, and at 2 and 4 months after therapy. No effort was made to change the oral hygiene habits of patients. Identification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed utilizing DNA technology at day 0 and 2 months after therapy. Twenty-three patients received metronidazole 250 mg plus amoxicillin 500 mg, 3 times/day for a week and 23 a placebo. Two patients in the placebo group were dropped at 2 months because they had taken antibiotics for medical reasons. Statistical analyses of differences between groups was done using the Mann-Whitney test, and the differences within each group were tested with ANOVA. There were no significant changes in surfaces with plaque in either group after therapy. The percentage of bleeding sites decreased significantly from baseline to 2 and 4 months in the M+A group (P = 0.001), and increased in the placebo group. Differences in bleeding on probing between groups were significant at 2 (P = 0.018), and 4 months (P = 0.005). The mean attachment level values at 2 and 4 months post-therapy improved significantly in the M+A group compared to the placebo group (P = 0.001). Treatment with M+A resulted in a significant mean reduction in probing depth at 2 and 4 months compared to baseline values (P = 0.001). The M+A group showed a significant reduction of sites with high levels of Pg (P = 0.001) at 2 months compared with baseline values, and there was a significant reduction of sites with Pg and Pi in the M+A group compared with the placebo group. The results showed that a combined M+A treatment as the only therapy changes the proportion of some subgingival microorganisms and allows a significant improvement in clinical conditions.

Effects of metronidazole in patients with "refractory" periodontitis associated with Bacteroides forsythus

The aim of the present study was to monitor the microbiological and clinical effects of renewed supra- and subgingival debridement in conjunction with systemic metronidazole therapy (500 mg TID for 7 days) in 27 "refractory" periodontitis patients, culture positive for Bacteroides forsythus and negative for Actinobacillus actinomycetemcomitans. Clinical evaluation included assessment of plaque, bleeding upon probing, probing pocket depth and clinical attachment loss at the deepest, bleeding site in each quadrant. Microbiological evaluation was carried out by anaerobic cultivation of subgingival plaque samples from the same sites. 6 months after renewed debridement and systemic metronidazole (RD+M), a statistically significant improvement of all clinical parameters was observed, except for the plaque index. After RD+M, B. forsythus was suppressed below detection level in 17 of the 27 patients, P. gingivalis in 9 out of 15 patients and P. intermedia in 14 of the 21 patients. Before RD+M, 12 patients harboured simultaneously B. forsythus, P. gingivalis as well as P. intermedia. Out of these, 6 patients were culture negative for the 3 species after therapy and showed the greatest reduction in pocket depth (3.1 mm) and gain of clinical attachment level (2.5 mm). In the treatment of refractory periodontitis, associated with patients culture positive for B. forsythus and negative for A. actinomycetemcomitans, metronidazole can significantly improve the clinical and microbiological parameters.

Effects of combined topical metronidazole and mechanical treatment on the subgingival flora in deep periodontal pockets in cuspids and bicuspids

The Effect on the subgingival microflora of a single topical administration of a 95% collagen and 5% metronidazole device in combination with debridement was investigated in 30 adult periodontitis patients in comparison with mechanical treatment alone. For each patient, plaque samples from test and control sites in cuspids and bicuspids were collected for culture and enumeration of total anaerobically cultivable bacteria (TA), black-pigmented anaerobes (BPA), and Actinobacillus actinomycetemcomitans (Aa). Spirochetes and fusiforms were quantified by direct microscopic examination after Giemsa staining. A decrease was observed for all parameters, and a significant difference in comparison with the control group was found for fusiforms. After treatment, a lower number of Aa positive sites were observed in the test group (13/25). These results show that a single application of topical metronidazole seems to be effective as adjunctive antimicrobial treatment in adult periodontitis.

A clinical and microbiological evaluation of systemic and local metronidazole delivery in adult periodontitis patients

The present study describes results on selected clinical and microbiological parameters obtained by treatment with local (Elyzol) and systemic (Flagyl) use of metronidazole alone and/or mechanical subgingival debridement in adult periodontitis. Patients were randomly divided into local and systemic treatment groups each comprising 5 individuals in each of whom 4 sites (one site/ quadrant) with a probing depth of > or = 5 mm were selected and treated with separate treatment modalities. The overall treatment design provided 6 different test groups. Groups of quadrants received: (1) scaling and root planing; (2) local metronidazole treatment; (3) systemic metronidazole treatment; (4) local metronidazole combined with scaling and root planing; (5) systemic metronidazole combined with scaling and root planing; (6) no treatment. The microbiological and clinical effects of treatment modalities were monitored over a period of 42 days. All treatments resulted in clinical improvements (gingivitis, probing pocket depth, attachment level) except for the untreated group. Parallel to the clinical changes, all treatments reduced the number of total bacteria and proportions of obligately anaerobic microorganisms. Although both of the combined treatment groups responded to therapy with better resolution of infection that the pure mechanical and pure metronidazole treatments, local metronidazole in combination with scaling and root planing seems to be more effective in terms of producing both clinical and microbial improvements.

Microbiological response to mechanical treatment in combination with adjunctive therapy. A review of the literature

The recognition of the microbial origin and the specificity of periodontal infections has resulted in the development of several adjunctive therapies (antibiotics and/or antiseptics) to scaling and root planing in the treatment of chronic adult periodontitis. This article aims to review the "additional" effect of a subgingival irrigation with chlorhexidine, or a local or systemic application of tetracycline or metronidazole, performed in combination with a single course of scaling and root planing in patients with chronic adult periodontitis. All treatment modalities are compared with scaling and root planing, based on their impact on: the probing depth (PD); total number of colony forming units per ml (CFU/ml); the proportions and/or the detection-frequency of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia; and/or on the percentages of cocci, spirochetes, motile, and other micro-organisms on dark field microscopy examination. All treatment modalities, including scaling and root planing without additional chemical therapy, resulted in significant reductions in the probing depth and the proportions of periodontopathogens, at least during the first 8 weeks post-therapy. However in comparison to a single course of scaling and root planing, the supplementary effect of adjunctive therapies seems to be limited. In general, only the irrigation with chlorhexidine 2%, the local application of minocycline, and the systemic use of metronidazole (in case of large proportions of spirochetes) or doxycycline (in case of large proportions of A. actinomycetemcomitans) seem to result in a prolonged supplementary effect when compared to scaling and root planing. Therefore, the use of antibiotics on a routine basis, especially in a systemic way, in the treatment of chronic adult periodontitis, can no longer be advocated, considering the increasing danger for the development of microbial resistance.

Potential of diagnostic microbiology for treatment and prognosis of dental caries and periodontal diseases

Most evidence suggests that only a finite number of bacteria are responsible for dental caries and periodontal diseases. This knowledge led to the development of microbial tests which can identify suspected pathogens. Current evaluation of the diagnostic power of microbial tests has shown that they have a low sensitivity and a low prognostic value. Despite these shortcomings, there are valid indications for microbiological-based diagnosis. Salivary microbial tests for the detection of mutans streptococci and lactobacilli may be useful, for example, in young children, oligosialic patients, and orthodontic patients. These tests can be used to monitor the success of chemopreventive measures or compliance with dietary recommendations. Microbial diagnosis, may also be valuable in the treatment of early-onset periodontitis or in subjects who respond poorly to periodontal therapy. The use of microbial tests to monitor the efficacy of chemotherapy or mechanical treatment is of particular interest.

Nonsurgical treatment of patients with periodontal disease

OBJECTIVE

To determine whether the short-term use of systemic antimicrobials (metronidazole or doxycycline) and locally delivered antimicrobials (metronidazole, chlorhexidine) in patients with advanced forms of periodontal disease could prevent the normally necessary access surgery.

STUDY DESIGN

Ninety-four patients were randomly assigned with the use of a double-blind protocol.

RESULTS

There was a 93% reduction in the need for periodontal surgery about individual teeth and an 81% reduction in the need for tooth extractions. Only 93 teeth of an initial total of 783 teeth actually needed surgery or extractions. Eighty-one percent of the patients entered into the maintenance phase of treatment without needing surgical treatments.

CONCLUSION

These findings indicate that a treatment paradigm based on the diagnosis and treatment of anaerobic infections is likely to be successful in those patients for whom access surgery is recommended.

Microbiological monitoring

If periodontal disease is due to a limited number of bacterial species, then continuous maximal plaque suppression is not the only possibility for prevention and therapy. Specific elimination or reduction of pathogenic bacteria from plaque becomes a valid alternative. Recent studies indicate that the elimination of certain putative pathogens is particularly difficult. New diagnostic methods should allow the choice of better suited procedures, make chosen procedures more effective (through better timing, dosage, selection of devices or drugs, increase of specificity, etc.) or lead to the elimination of unnecessary work (e.g., the treatment of non-susceptible sites or patients). The benefit of newly proposed tests depends on the possible impact of the obtained information on clinical decisions and on the consequences these decisions have for treatment. Thus, diagnostic methods and therapeutical options have to be evaluated together.

Passive immunization with monoclonal antibodies against Porphyromonas gingivalis in patients with periodontitis

Selective inhibition of recolonization of Porphyromonas gingivalis was investigated by topical application of monoclonal antibody (MAb). To select a MAb to P. gingivalis with the potential for recognizing most strains of P. gingivalis, we examined seven MAbs, one of which (MAb 61BG 1.3) recognized all 22 laboratory strains and serotypes of P. gingivalis tested as well as 105 human clinical isolates. A comparative study of the number of P. gingivalis bacteria identified by conventional culture and immunofluorescence with MAb 61BG 1.3 showed a very significant correlation between the two methods (Spearman r = 0.85, P < 0.001). Fourteen patients with periodontitis, who harbored P. gingivalis in their subgingival plaque, were treated by root planing and with metronidazole to suppress any detectable P. gingivalis. In this double-blind study, the patients were then divided randomly into two groups; one was treated with MAb to P. gingivalis, and the other was treated with saline. Each patient had four subgingival applications of 3 micrograms of MAb (or saline) per tooth at 1, 3, 7, and 10 days after P. gingivalis was suppressed. The number of P. gingivalis bacteria was then monitored, and significantly less recolonization of the sites with the most severe periodontitis was found in the MAb-treated patients than in the control patients (P < 0.01). This was evident at 6 and 9 months after the application of MAb, but by 12 months, P. gingivalis, was also found to recolonize these sites in two of the MAb-treated patients. The effect of MAb was specific to P. gingivalis, since the numbers of spirochetes were not significantly different between the two groups. However, no significant difference in any clinical periodontal indices between the immunized and control patients at 6 and 12 months was observed. This is the first demonstration that a putative periodontal pathogen can be selectively prevented from recolonization for up to 9 months in sites with the most severe periodontitis. This strategy could be used to establish directly in humans whether a microorganism is involved in the pathogenesis of periodontitis, by repeated application of the corresponding MAb at about 6-month intervals and by comparing the clinical indices between the MAb-treated and control patients.

Clinical and microbiological changes associated with the use of 4 adjunctive systemically administered agents in the treatment of periodontal infections

The purpose of the present investigation was to assess the effects of periodontal surgery and 4 systemically administered agents, Augmentin, tetracycline, ibuprofen or a placebo on clinical and microbiological parameters of periodontal disease. 98 subjects were monitored at 2-month intervals at 6 sites per tooth for clinical parameters. Subgingival plaque samples were taken from the mesial surface of each tooth at each visit and evaluated for their content of 14 subgingival species using DNA probes and a colony lift method. 40 subjects who exhibited loss of attachment > 2.5 mm at 1 or more sites during longitudinal monitoring were treated using modified Widman flap surgery at sites with probing pocket depth > 4 mm, subgingival scaling at all other sites and were randomly assigned 1 of the 4 agents. Treatment was completed within 30 days during which time the subject took the assigned agent. Overall, subjects exhibited a mean attachment level "gain" of 0.34 +/- 0.10 mm (SEM) and a mean pocket depth reduction of 0.62 +/- 0.09 mm 10 +/- 4 months post-therapy. However, certain subjects in each treatment group showed a poor response. Subjects receiving antibiotics exhibited significantly more attachment level "gain" (0.57 +/- 0.15 mm, SEM) than subjects receiving either ibuprofen or a placebo (0.02 +/- 0.10). The differences between Augmentin and tetracycline groups were not significant, nor were the differences between ibuprofen and placebo. 10 months post-therapy, there was a reduction in the number of sites colonized in any subject group by detectable levels (10(3)) of P. gingivalis. Species showing similar reductions were B. forsythus, P. intermedia and P. micros. Subjects receiving systemically administered antibiotics had a significant increase in the proportion of sites colonized by C. ochracea coupled with a greater decrease in the number of sites colonized by P. gingivalis, B. forsythus, P. intermedia and P. micros post-therapy than subjects not receiving antibiotics. The results of this investigation indicate that adjunctive systemic antibiotics increase periodontal attachment "gain" and decrease the levels of some suspected periodontal pathogens in subjects with evidence of current disease progression.

Topical metronidazole as an adjunct to subgingival debridement in the treatment of chronic periodontitis

The purpose of this study was to evaluate the clinical effects of a single application of a 5% metronidazole collagen device in periodontal pockets deeper than 5 mm, in association with debridement and without reinforcement of home care and hygiene as practiced by the patient at any time. Pocket depth, attachment level, bleeding on probing, gingival index and plaque index were assessed at baseline, and on days 15, 30 and 90. Analysis of data from 28 patients indicated that both debridement and metronidazole therapy decreased pocket depth, bleeding on probing and gingival index, but results were significantly better with metronidazole. These results indicate that topical metronidazole provides an effective adjunctive treatment of advanced periodontitis.

The efficacy of tinidazole in naturally occurring periodontitis in dogs: bacteriological and clinical results

The efficacy of tinidazole in addition to a single course of scaling was studied in 14 dogs with periodontitis. Three test teeth, two with periodontitis and one with healthy periodontium, were selected per dog. Subgingival bacterial samples were taken, and clinical examination was carried out at each of four visits (0, 14, 90 and 180 days). The bacterial samples were cultured anaerobically using selective and nonselective media. All teeth in the dentition, except one diseased test tooth with periodontitis were scaled at the first visit and tinidazole or placebo administered twice a day for 7 days. The mean probing depth of the diseased test pockets was significantly more reduced in tinidazole+scaling (T1S1) than scaling alone (T0S1) group at all visits compared to baseline values. The most significant decreases of bacterial counts in T1 or T0 groups were found in agar corroding Gram-negative rods in both diseased and healthy T1S1 pockets and in slimy Gram-negative rods in diseased T1S0 pockets between visits 1 and 2. The intergroup comparisons showed that Gram-positive cocci decreased significantly more in S1 pockets as well as sporeforming Gram-positive rods in diseased S0 pockets of T1 than T0 group. The highest number of isolates was found in the group of pigmented Gram-negative anaerobe rods, mainly Porphyromonas spp. The percentage of Porphyromonas gingivalis-like isolates decreased to zero and Porphyromonas endodontalis-like isolates increased in all test teeth of T1 group at 14 days. It is concluded that tinidazole has good efficacy against P. gingivalis-like bacteria which seem to be periodontal pathogens in dogs.

The role of metronidazole in the treatment of periodontal diseases

This article discusses the ability of metronidazole to improve periodontal health. Review of the drug's pharmacology and potential side effects indicate that it poses little threat to humans of inducing acute toxicity, mutagenesis, or cancer if used according to recommended dosing regimens. Studies addressing metronidazole utilization in a variety of clinical conditions demonstrate that its routine use does not enhance root planing. However, adjunctive antibiotic therapy may be advantageous in the treatment of sites where effective root planing is precluded due to deep pockets or when anaerobic periodontal infections do not respond to conventional therapy.

Metronidazole in periodontitis: reduced need for surgery

A considerable amount of circumstantial evidence indicates that most forms of periodontitis are due to the presence or dominance of a finite number of bacterial species in the subgingival plaque. Almost all of the putative pathogens are anaerobic species, indicating that most forms of periodontitis could be diagnosed as anaerobic infections. In this double-blind investigation, patients with elevated proportions or levels of spirochetes in 2 or more plaque samples, i.e., 60% spirochetes, were randomly assigned to receive either metronidazole, 250 mg 3 x a day for 1 week, or placebo (positive-control) after the completion of all debridement procedures. When the patients were re-examined 4 to 6 weeks later, the patients in the metronidazole group (n = 15) exhibited a highly significant (p less than 0.01) reduction in probing depth and apparent gain in attachment levels relative to the patients (n = 18) in the positive-control group about those teeth that initially had probing depths of 4 to 6 mm. This pattern was also observed about teeth that initially had probing depths greater than or equal to 7 mm. This reduction in probing depths and apparent gain in attachment was associated with a significant reduction in the need for periodontal surgery in the metronidazole-treated patients (difference 8.4 teeth per patient) compared to the positive-control patients (2.6 teeth per patient). These clinical improvements in the metronidazole group were associated with significantly lower proportions of spirochetes, selenomonads, motile rods, and P. intermedius, and a significantly higher proportion of cocci in the plaques. These findings indicate that systemic metronidazole, when given after all the root surface debridement is completed, leads to additional treatment benefits, including a reduced need for surgery, beyond that which can be achieved by debridement alone.

Using antimicrobial agents to manage periodontal diseases

Periodontal diseases are bacterial infections and anti-microbials have been shown to be useful in their treatment and prevention. State-of-the-art treatment of refractory forms of destructive periodontal disease presently includes adjunctive use of systemic antibiotics directed to eliminating or suppressing pathogenic subgingival bacteria. Also, local application of antimicrobials by subgingival deposition or their use as irrigants during periodontal therapy are soon likely to be major components of anti-infective management of periodontal diseases. A new approach to anti-infective periodontal therapy combines ultrasonic surgical debridement with antimicrobial irrigation.