Effects of short-term administration of metronidazole on the subgingival microflora

The effect of metronidazole plus amoxicillin or metronidazole plus penicillin V on periodontal pathogens in an in vitro biofilm model

A combination of metronidazole (MET) and amoxicillin (AMX) is commonly used as adjunct to mechanical therapy of periodontal disease. The use of broad spectrum antibiotics such as AMX may contribute to development of antibiotic resistance. The aim was to evaluate the in vitro effect of replacing AMX with penicillin V (PV) in combination with MET on a biofilm model. A biofilm model consisting of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum was developed. The biofilms were exposed to AMX + MET and PV + MET in two different concentrations. Bacterial viability in biofilms following antibiotic exposure was assessed by viable counts and by confocal microscopy. No live colonies of P. gingivalis nor F. nucleatum were retrieved from biofilms exposed to AMX + MET or PV + MET. The amount of A. actinomycetemcomitans was 4-5 logs reduced following antibiotic treatment; no statistical significance was achieved between AMX + MET or PV + MET treated biofilms. Replacement of AMX with PV at the same concentration, in combination with MET, resulted in similar effect on bacterial viability in this in vitro model. The option of using PV + MET instead of AMX + MET deserves further investigation, as this may contribute to reduce the risk of antibiotic resistance development.

Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population. I. Clinical results

OBJECTIVE

The current investigation evaluated the clinical effects of scaling and root planing (SRP) alone or in combination with systemic metronidazole and/or repeated professional removal of supragingival plaque in subjects with chronic periodontitis.

METHODS

Fourty-four adult subjects (mean age: 45+/-6 years) with periodontitis were randomly assigned to four treatment groups; a control (C, n=10) that received SRP and placebo and three test groups treated as follows: Test 1 (T1) (n=12) received SRP and metronidazole (400 mg t.i.d., M) for 10 days; Test 2 (T2) (n=12) received SRP, weekly professional supragingival plaque removal for three months (professional cleaning (PC)) and placebo; and Test 3 (T3) (n=10) received SRP, M and PC. Pocket depth (PD), attachment level (AL), bleeding on probing (BOP) and presence of visible plaque and suppuration were measured at six sites per tooth at baseline and at 90 days post-therapy. Significance of differences over time was determined using the Wilcoxon test, and among groups using ancova.

RESULTS

A reduction in full-mouth mean clinical parameters was observed at 90 days after all therapies. Sites with baseline PD<4 mm showed an increase in mean PD in the control group and in mean AL in all treatment groups. Sites with baseline PD of 4-6 mm in subjects who received PC as part of therapy (T2, T3) showed a marked reduction in PD, AL and in the % of sites with BOP. Subjects who received metronidazole (T1 and T3) showed the best clinical response at sites with an initial PD of >6 mm. The major clinical benefit occurred when the combination of SRP, M and PC was used. Group T3 showed the least attachment loss in initially shallow pockets. This group also exhibited the greatest reduction in the % of sites with BOP and suppuration as well as in mean PD and AL at sites with baseline PD>4 mm.

CONCLUSION

The data suggest a significant clinical benefit in combining SRP, systemic metronidazole and weekly professional supragingival plaque removal for the treatment of chronic periodontitis.

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.

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.

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.

Systemic doxycycline administration in the treatment of periodontal infections (I). Effect on the subgingival microbiota

Systemic doxycycline is one of the more common antimicrobial agents used in the treatment of periodontal infections and yet little is known of its effect on subgingival plaque composition during and after its administration. The purpose of the present investigation was to evaluate changes in subgingival plaque composition during and after 14 days of doxycycline administration. 20 subjects with adult periodontitis were randomly assigned to test (n = 10) and control (n = 10) groups. The subjects received full mouth clinical assessment of pocket depth, attachment level, BOP, gingival redness, suppuration and plaque accumulation at baseline and 90 days. All subjects received full mouth SRP at baseline and, additionally, the test group received 100 mg doxycycline daily for 14 days. Subgingival plaque samples were taken from the mesial surface of up to 28 teeth in each subject at baseline and 90 days. In addition, plaque samples were taken from 2 randomly selected teeth at 3, 7 and 14 days during and after antibiotic administration. Control subjects were sampled at the same time points. Counts of 40 subgingival species were determined using checkerboard DNA-DNA hybridization and fluorescent detection. Significance of differences between test and control groups was determined at each time point using the Mann Whitney test. Significance of changes over time within test and control groups was determined using the Quade test. A modest but significant reduction in mean pocket depth from baseline to 90 days occurred in both test and control groups. A significant decrease in the % of sites with gingival redness occurred in the test group. There were no significant differences in proportions between test and control groups for 33 of the test species at any time point. Test subjects exhibited lower proportions of 4 Actinomyces species and an increase in 3 Streptococcus species during antibiotic administration. After cessation of doxycycline, Actinomyces sp. increased while Streptococcus sp. returned to baseline proportions. The relationship between these 2 genera appeared to be reciprocal; an increase in one was accompanied by a decrease in the other. Periodontal pathogens including B. forsythus, P. gingivalis, T. denticola and A. actinomycetemcomitans were not significantly altered by oral administration of doxycycline using conventional therapeutic dosage.

Longitudinal effect of non-surgical treatment and systemic metronidazole for 1 week in smokers and non-smokers with refractory periodontitis: a 5-year study

BACKGROUND

Periodontitis consists of a mixture of diseases, most of which respond favorably to traditional mechanical therapy. It is now recognized that advanced periodontitis does not always respond to conventional management with scaling, periodontal surgery, and oral hygiene measures. However, various types of antibiotics given systemically or locally improve the success rate of periodontal therapy. In short-term studies, it has been shown that metronidazole, when systemically administered after debridement, resulted in treatment benefits including less need for surgical intervention.

METHODS

In this double-blind study, we evaluated periodontal treatment involving initial non-surgical treatment, systemic administration of metronidazole for 1 week, and then follow-ups for scaling and root planing every 6 months, for 5 years. The study population consisted of 64 subjects (37 smokers and 27 non-smokers), mean age 36.3 (+/-3.0 SD) years, with severe periodontal disease. After initial scaling and root planing, patients were randomly assigned to the intervention or placebo groups: 400 mg metronidazole or a placebo administered at 8-hour intervals for 1 week. The participants underwent an extensive clinical periodontal examination. Gingival crevicular fluid (GCF) was analyzed for spirochetes and granulocytes. Samples were cultured for Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas gingivalis (Pg.), and Prevotella intermedia (Pi.).

RESULTS

The number of patients infected with A.a., Pg., Pi., and spirochetes decreased during the study. Most patients who harbored spirochetes at the end of the study had these microorganisms at the beginning. Smokers responded less favorably to periodontal therapy than non-smokers. Non-smoking patients who required only non-surgical therapy in the intervention group showed statistically significant improvement in the clinical parameters after 5 years. Patients with complete healing, defined as the absence of inflamed sites > or =5 mm, after 5 years were found only in the intervention group. The patients considered healthy after 5 years were the same patients found to be healthy after 6 months.

CONCLUSIONS

Decisive factors in the sustained long-term improvement of patients who respond satisfactorily to treatment are probably initial scaling and root planing; a brief course of metronidazole; and regular follow-up examinations at 6-month intervals for oral hygiene and scaling and root planing.

Additional clinical and microbiological effects of amoxicillin and metronidazole after initial periodontal therapy

The aims of this study were to evaluate the clinical and microbiological effects of initial periodontal therapy (IT) and to determine the additional effects of systemic amoxicillin (Flemoxin Solutab) 375 mg TID plus metronidazole 250 mg TID therapy, in patients with adult Actinobacillus actinomycetemcomitans (Aa)-associated periodontitis in conjunction with either Porphyromonas gingivalis (Pg), Bacteroides forsythus (Bf) and/or Prevotella intermedia (Pi). In addition the adverse effects of the antimicrobial therapy were also documented. A total of 22 patients were enrolled. The deepest, bleeding pocket in each quadrant was selected and at these 4 experimental sites clinical measurements and microbiological testing was carried out at baseline, after (IT), i.e., 21 weeks after baseline, and after antimicrobial therapy (AM), i.e., 35 weeks after baseline. At baseline, the mean plaque index (PI) amounted 0.5, 0.1 after IT and 0.3 after systemic AM. The mean bleeding index decreased from 1.6 to 1.2 after IT and a further decrease to 0.7 after AM was noted. Suppuration was completely eliminated after AM. The mean change of probing pocket depth (PPD) after IT amounted 1.4 mm and was further reduced with an additional mean change of 1.1 mm after medication. Clinical attachment gain was 1.1 mm after IT and an additional 0.9 mm was observed after AM. One of the 22 Aa positive patients and 4 of 17 Pg positive patients became negative for these species after IT. The number of patients with detectable Pi decreased from 16 to 10 after IT. After AM, in comparison to baseline, suppression below detection level for Aa was achieved in 19 out of 22, for Pg in 9 out of 17, for Bf in 13 out of 14, and for Pi in 11 out of 16 patients. By contrast, higher frequencies of Peptostreptococcus micros and Fusobacterium nucleatum were found after AM. On the basis of the microbiological results the study group was separated into 2 subgroups: group A consisted of subjects who had no detectable levels of Aa, Pg, Bf and <5% of Pi after AM. Group B consisted of those who still showed presence of one of these 3 species and/or > or =5% levels of Pi. After AM, group B had significantly higher PI, BI, PPD and CAL scores then group A. It is concluded that group A showed low plaque scores and no detectable periodontal pathogens. This microbiological condition has been associated with a long-term stable periodontium.

Differential clinical treatment outcome after systemic metronidazole and amoxicillin in patients harboring Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis

48 adult patients with untreated periodontitis harboring subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis as assessed by PCR were randomly assigned to receive full-mouth scaling alone (control) or scaling with systemic metronidazole plus amoxicillin and supragingival irrigation with chlorhexidine digluconate (test). In patients harboring A. actinomycetemcomitans intraorally at baseline, the adjunctive antimicrobial therapy resulted in a significantly higher incidence of probing attachment level (PAL) gain of 2 mm or more compared to scaling alone over 12 months (p<0.05). In addition, suppression of A. actinomycetemcomitans in subgingival plaque below detectable levels was associated with an increased incidence of PAL gain. In contrast, patients initially harboring P. gingivalis but not A. actinomycetemcomitans in the oral cavity showed a significantly higher incidence of PAL loss following adjunctive antimicrobial therapy compared to scaling alone (p<0.05). When the presence of pathogens at baseline was disregarded in the analysis, adjunctive antimicrobial therapy did not significantly enhance clinical treatment outcome. The results indicated that adults with untreated periodontitis harboring A. actinomycetemcomitans may benefit from the adjunctive antimicrobial therapy for a minimum of 12 months, whereas, the regimen may adversely affect the clinical treatment outcome of patients harboring P. gingivalis but not A. actinomycetemcomitans.

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.

Meta-analysis of the effect of systemic metronidazole as an adjunct to scaling and root planing for adult periodontitis

The purpose of this meta-analysis was to provide a quantitative overview of clinical trials assessing the use of systemic metronidazole (S-MET) as an adjunct to scaling and root planning (S&RP) in the treatment of adult periodontitis. Eight clinical trials were chosen based upon a priori selection criteria, and two outcomes, "reduction in probing pocket depth" (PD) and "gain in clinical attachment level" (CAL), were analyzed. Results for each outcome were stratified by initial PD 1-3 mm, 4-6 mm, or > or = 7 mm and length of follow-up 4-6 wk, 9-13 wk, or 14-26 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing PD where initial PD was 4-6 mm and follow-up was 9-13 wk (0.43 mm; 99% CI 0.12, 0.73). No significant advantage was observed for S-MET for reducing PD where initial PD was less than 4 mm or follow-up was longer than 13 wk. S-MET in conjunction with S&RP was superior to S&RP alone in reducing CAL where initial PD was 4-6 mm and follow-up was 4-6 wk (0.29; 99% CI 0.01, 0.58) and where follow-up was 9-13 wk (weighted mean difference 0.32; 99% CI 0.03, 0.61). Significant heterogeneity of effect was not seen for PD or Cal at any level of initial PD or length of follow-up. No significant dose-response relationship was observed. This meta-analysis was limited due to diversity of data presentation and the small number of trials in each stratum. These results suggest that S-MET in conjunction with S&RP may offer a benefit over S&RP alone in the treatment of adult periodontitis patients in managing pockets of 4 mm or greater, but the additional benefit was not evident if initial PD was less than 4 mm or follow-up was beyond 13 wk.

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.

Pharmacological control of periodontal disease. II. Antimicrobial agents

Antimicrobial agents are of value in the management of certain types of periodontal disease, notably early onset, juvenile and refractory periodontitis. The diagnosis of these conditions is often made on clinical grounds but microbial sampling of the pocket flora is of value in determining the type of antimicrobial therapy. Routine systemic use of these drugs in the management of chronic adult periodontitis is contraindicated, and is no substitute for root surface debridement and thorough supragingival plaque control. Tetracyclines and metronidazole are the agents most frequently used in the management of periodontal disease. Both drugs can be given systemically or applied topically into the periodontal pocket. The latter route is preferred since the dose is reduced considerably, but the local tissue concentration is increased. The efficacy of local drug delivery is dependent upon the release kinetics of the drug from the delivery vehicle. Although local application can be time consuming, it reduces the risk of adverse reactions and drug interactions. The tetracyclines have the additional advantage of inhibiting collagenases. This property may facilitate repair and new attachment formation. Systemic metronidazole appears to be useful as an adjunct to conventional periodontal therapy. The combination of metronidazole 250 mg and amoxycillin 375 mg has been shown to be effective in the treatment of refractory periodontitis, including cases which are resistant to tetracycline. Clindamycin has also been used in the management of refractory periodontitis, but the unwanted effects of this drug must limit its systemic use for this purpose.

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.

Microbiology in the management of destructive periodontal disease

This paper summarizes the rationale for the application of microbiology in the management of destructive periodontal diseases. The subgingival microbiota in patients with severe periodontitis is complex and contains high numbers of obligate anaerobic bacteria as well as facultative micro-organisms. It has become clear that major differences exist in the composition of the subgingival microflora. These differences are not only quantitative but also qualitative. Difference in plaque composition is the basis for the application of clinical microbiology in the management of periodontal disease. Several bacterial species have emerged as useful indicators for progressive periodontitis. In this respect, the importance of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius has been shown in a number of studies. It has become clear that A. actinomycetemcomitans is not specifically associated with the local form of juvenile periodontitis, but this micro-organism is probably also of importance in severe periodontitis in adult patients. Selection of individuals with an A. actinomycetemcomitans associated periodontitis is essential since successful treatment in these patients needs an adjunctive antibiotic therapy. Microbiological testing can be useful in patients showing a poor response to periodontal treatment (refractory periodontitis). Factors which may be responsible include poor oral hygiene, poor subgingival debridement, the patient's susceptibility and a subgingival microflora resistant to therapy. In this patient category, microbiological testing is capable of diverting continuing periodontal treatment. Furthermore, microbiology can be useful in evaluating periodontal treatment. Successful elimination of specific periodontopathic microorganisms can be used to determine recall intervals.

Preserving the motility of microorganisms

This study focused on several factors that may influence the percentage of motile microorganisms in a sample from the tongue determined using a phase-contrast microscope. It was found that the time elapsing between sampling and analysis is crucially important. In both sterile saline and reduced transport fluid (RTF), a reduction of the percentage of motile microorganisms was found within 15-30 min after sampling respectively. In order to be able to prolong the time interval between sampling and analysis, it was found that storing a sample in a tuberculin syringe with RTF supplemented with Fildes extract preserved the motility of the microorganisms and gave no significant reduction in the percentage of motiles within 48 h.

Antibiotics in periodontal therapy: advantages and disadvantages

Antibiotic treatment of periodontitis aims at eradicating or controlling specific pathogens. Prime candidates for antibiotic therapy are patients with recently diagnosed active periodontitis or a history of recurrent disease who fail to stabilize following mechanical/surgical therapy. Since a variety of microbes with differing antimicrobial susceptibility profiles may cause periodontitis, selection of antimicrobial agents should be based on proper microbial diagnosis and sensitivity testing, as well as consideration of the patient's medical status. The risk of treating chemotherapeutically solely on the basis of clinical features, radiographic findings or a limited microbiological analysis, is failure to control the pathogens or overgrowth of new pathogens. A review of published papers reveals that appropriate systemic antibiotic therapy may enhance healing in patients with recent or high risk of periodontal breakdown. Systemic antibiotic therapy seems more predictable than topical administration in eradicating periodontal pathogens from deep periodontal pockets. Several promising antimicrobial agents for periodontitis treatment need testing in placebo-controlled, double-blind, randomized clinical trials.

The effect of systemic metronidazole after non-surgical treatment in moderate and advanced periodontitis in young adults

The effect of adjunctive systemic metronidazole was studied in patients with moderate and advanced periodontitis recalcitrant to comprehensive non-surgical treatment. The material originated from a randomly selected part of the population aged 31 to 40 years. After non-surgical treatment of 149 patients, 98 with persisting pathological pockets greater than or equal to 5 mm (52 men and 46 women) became the subjects for the study. Clinical parameters were registered and pocket contents subjected to laboratory analysis. The subjects were randomized into two groups according to a code list known only by the manufacturer and the statistician. The test group took three 400 mg metronidazole tablets daily for 1 week and the control group took placebo tablets. Reassessment 6 months later showed statistically significant clinical improvement, with a reduction in the number of sites greater than or equal to 5 mm in both test and control groups. Complete healing, with no pockets greater than or equal to 5 mm, was noted in 30% of the test group and 9% of the control group. The difference is statistically significant and shows the supplementary effect of adjunctive metronidazole in non-surgical treatment of moderate and advanced periodontitis.

Report of Committee on Scientific Investigation of the American Academy of Restorative Dentistry

A few personal points seem appropriate in summary. It is axiomatic that while research solves problems, it also creates them. As an example, it is an accepted fact that dentistry more than any other profession has made serious inroads into putting itself out of business through research. Each year this report takes note of the reduction in dental caries in children, which has thus triggered a change in the nature of general practice. Be this as it may, it is well to acknowledge that major dental diseases are not disappearing, but their patterns in the population are changing, accompanied by an expansion of other services. Despite the optimistic picture painted earlier in this report, it is grossly premature to acclaim the elimination of caries, and thereby a significant segment of restorative dentistry. Of course the younger age groups have been the major beneficiaries of caries reduction. As the child ages from 9 to 16 years, the percentage of mouths free of caries drops by one half. In addition, the disease pattern in the adult population is being altered because of a longer life span and loss of fewer teeth. Unquestionably what we will, and are already seeing, is not an elimination of restorative dentistry but a different target and changes in procedures because of new materials, therapy, and expanded scope of services. There is yet another subtle change in the trend of dental research and it deals with the reduction in the number of dental schools worldwide and smaller class sizes in those schools. Dental research thereby suffers because of the traditional link between education and research. Thus the potential pool of researchers becomes smaller and research monies for training programs for dental investigators, particularly in clinical research, decreases. This year a surprising number of articles are concerned with manpower as it relates to research priorities. So, it is indeed a time that both the profession and the scientific community find filled with controversy and frustration. Yet never has there been a time that offers more in challenges and rewards.