Tetracycline fiber therapy monitored by DNA probe and cultural methods

Supra and subgingival application of antiseptics or antibiotics during periodontal therapy

Periodontal diseases (gingivitis and periodontitis) are characterized by inflammatory processes which arise as a result of disruption of the balance in the oral ecosystem. According to the current S3 level clinical practice guidelines, therapy of patients with periodontitis involves a stepwise approach that includes the control of the patient's risk factors and the debridement of supra and subgingival biofilm. This debridement can be performed with or without the use of some adjuvant therapies, including physical or chemical agents, host modulating agents, subgingivally locally delivered antimicrobials, or systemic antimicrobials. Therefore, the main aim of this article is to review in a narrative manner the existing literature regarding the adjuvant application of local agents, either subgingivally delivered antibiotics and antiseptics or supragingivally applied rinses and dentifrices, during the different steps in periodontal therapy performed in Europe.

The effect of drug dose and duration of adjuvant Amoxicillin-plus-Metronidazole to full-mouth scaling and root planing in periodontitis: a systematic review and meta-analysis

OBJECTIVES

The aim is to explore the optimal drug dose and duration of adjunctive Amoxicillin-plus-Metronidazole (AMX/MET) to full-mouth scaling and planing (FMSRP) in periodontitis.

METHODS

An electronic search in four databases and manual search in four journals were conducted for randomised clinical trials comparing AMX/MET adjunct to FMSRP with FMSRP alone for at least 3 months.

RESULTS

Eleven studies were eligible and included. The primary outcome was clinical attachment level (CAL) gain, the secondary outcomes were periodontal pocket depth (PPD) reduction and adverse events. Our results showed a beneficial effect of adjunctive AMX/MET with higher drug dose to FMSRP for CAL gain and PPD reduction at 3 months, and the benefit remained stable at 6 months. However, minimal difference among three-seven-and ten-day drug duration was observed. In addition, the risk difference of adverse events was minimal between two groups.

CONCLUSION

FMSRP adjunct to a high drug dose of 500/500 mg of AMX/MET showed a significant and stable improvement on 6-month follow-up period. No decision for drug duration could be made due to limited evidence.

CLINICAL RELEVANCE

On 6-month follow-up, higher dose of AMX/MET adjunct to FMSRP could provide a stable clinical effect. No recommendation for drug duration could be made.

The salivary microbiome is altered in the presence of a high salivary glucose concentration

Background

Type II diabetes (T2D) has been associated with changes in oral bacterial diversity and frequency. It is not known whether these changes are part of the etiology of T2D, or one of its effects.

Methods

We measured the glucose concentration, bacterial counts, and relative frequencies of 42 bacterial species in whole saliva samples from 8,173 Kuwaiti adolescents (mean age 10.00 ± 0.67 years) using DNA probe analysis. In addition, clinical data related to obesity, dental caries, and gingivitis were collected. Data were compared between adolescents with high salivary glucose (HSG; glucose concentration ≥ 1.0 mg/d, n = 175) and those with low salivary glucose (LSG, glucose concentration < 0.1 mg/dL n = 2,537).

Results

HSG was associated with dental caries and gingivitis in the study population. The overall salivary bacterial load in saliva decreased with increasing salivary glucose concentration. Under HSG conditions, the bacterial count for 35 (83%) of 42 species was significantly reduced, and relative bacterial frequencies in 27 species (64%) were altered, as compared with LSG conditions. These alterations were stronger predictors of high salivary glucose than measures of oral disease, obesity, sleep or fitness.

Conclusions

HSG was associated with a reduction in overall bacterial load and alterations to many relative bacterial frequencies in saliva when compared with LSG in samples from adolescents. We propose that hyperglycemia due to obesity and/or T2D results in HSG and subsequent acidification of the oral environment, leading to a generalized perturbation in the oral microbiome. This suggests a basis for the observation that hyperglycemia is associated with an increased risk of dental erosion, dental caries, and gingivitis. We conclude that HSG in adolescents may be predicted from salivary microbial diversity or frequency, and that the changes in the oral microbial composition seen in adolescents with developing metabolic disease may the consequence of hyperglycemia.

Evaluation of efficacy of tetracycline fibers in conjunction with scaling and root planing in patients with chronic periodontitis

AIM

The objective of this study was to compare the efficacy of scaling and root planing (SRP) alone versus tetracycline fiber therapy used adjunctively with SRP in the treatment of chronic periodontitis sites in maintenance patients.

MATERIALS AND METHODS

A total of 30 patients with a diagnosis of chronic periodontitis (60 localized chronic periodontitis sites) in the age group of 35 to 55 were selected. None of these patients had received any surgical or non-surgical periodontal therapy and had sites of periodontal pockets measuring 4-7 mm clinically and demonstrated radiographic evidence of moderate bone loss. Two non-adjacent sites in separate quadrants were selected in each patient for monitoring based on criteria that the sites had localized chronic periodontitis. Plaque index (PI) (sillness and loe) and Gingival-bleeding index (GI) (loe and sillness) were measured at baseline and 15(th), 30(th), 60(th), and 90(th)day. Clinical pocket depth (PD) and microbial analysis (MA) were analyzed at baseline and 90(th) day.

RESULTS

At 0 and 3 months adjunctive tetracycline fiber therapy was significantly better in reducing PI, GBI, (P<0.001) than S and RP alone. In comparison, the reduction in the PD was non-significant at 0 and 3 months (P<0.001). The microbial analysis showed significant reduction in Porphyromonas gingivalis and Prevotella intermedia though there was no significant reduction in the Actinobacillus actinomycetemcomitans.

CONCLUSION

Overall, these results indicate that fiber therapy significantly enhanced the effectiveness of SRP in the management of chronic periodontitis.

Do probiotics offer opportunities to manipulate the periodontal oral microbiota?

BACKGROUND

As in other fields of healthcare, probiotics have been introduced for prevention and treatment of periodontal diseases.

OBJECTIVE

This review was initiated to explore whether the use of probiotics can influence the periodontal microbiota and periodontal health.

MATERIALS AND METHODS

Literature on the mode of action of oral probiotics was reviewed and a systematic review was performed on the microbiological and clinical effects of oral probiotics on periodontal health.

RESULTS

Three animal and 11 in vivo human studies were retrieved. Six studies reported on microbiological effects whereas eight studies report on clinical effects. Seven studies were performed on healthy or gingivitis patients and four studies on periodontitis patients. Many of the retrieved studies are pilot in nature and with low quality. The high degree of heterogeneity between studies hampered analysis.

CONCLUSION

Taking into consideration all limitations, the currently available data indicate an effect of probiotics on the oral microbiota and a more limited effect on clinical periodontal outcome measures. However, there is an urgent need for properly conducted clinical trials where probiotics are used as adjuncts to standard periodontal care, similar to antibiotics, using probiotic strains with, at least at an in vitro level, proven periodontal probiotic effects.

Guiding periodontal pocket recolonization: a proof of concept

The complexity of the periodontal microbiota resembles that of the gastro-intestinal tract, where infectious diseases are treatable via probiotics. In the oropharyngeal region, probiotic or replacement therapies have shown some benefit in the prevention of dental caries, otitis media, and pharyngitis, but their effectiveness in the treatment of periodontitis is unknown. Therefore, this study addressed the hypothesis that the application of selected beneficial bacteria, as an adjunct to scaling and root planing, would inhibit the periodontopathogen recolonization of periodontal pockets. Analysis of the data showed, in a beagle dog model, that when beneficial bacteria were applied in periodontal pockets adjunctively after root planing, subgingival recolonization of periodontopathogens was delayed and reduced, as was the degree of inflammation, at a clinically significant level. The study confirmed the hypothesis and provides a proof of concept for a guided pocket recolonization (GPR) approach in the treatment of periodontitis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Benefit of “one-stage full-mouth disinfection” is explained by disinfection and root planing within 24 hours: a randomized controlled trial

OBJECTIVES

The beneficial effects of the one-stage, full-mouth disinfection remain controversial in the scientific literature. This might be due to the fact that an entire mouth disinfection with the use of antiseptics has been confused with a full-mouth scaling and root planing. This parallel, single blind RCT study aimed to compare several full-mouth treatment strategies with each other.

MATERIAL AND METHODS

Seventy-one patients with moderate periodontitis were randomly allocated to one of the following treatment strategies: scaling and root planing, quadrant by quadrant, at two-week intervals (negative control, NC), full-mouth scaling and root planing within 2 consecutive days (FRP), or three one-stage, full-mouth disinfection (FM) protocols within 2 consecutive days applying antiseptics to all intra-oral niches for periopathogens using as antiseptics: chlorhexidine (FMCHX) for 2 months, amine fluoride/stannous fluoride for 2 months (FMF), or chlorhexidine for 2 months followed by amine fluoride/stannous fluoride for another 6 months (FMCHX+F). At baseline and after 2, 4, and 8 a series of periodontal parameters were recorded.

RESULTS

All treatment strategies resulted in significant (p<0.05) improvements of all clinical parameters over the entire duration of the study. Inter-treatment differences were often encountered. The NC group nearly always showed significant smaller improvements than the two CHX groups. The differences between the FRP or FM groups, and the two CHX groups only sporadically reached a statistical significance.

CONCLUSION

These observations indicate that the benefits of the "OSFMD" protocol are partially due to the use of the antiseptics and partially to the completion of the therapy in a short time.

Initial subgingival colonization of 'pristine' pockets

The treatment of periodontitis/peri-implantitis involves the reduction/eradication of periopathogens. After therapy, beneficial and pathogenic species recolonize the subgingival area. The dynamics of recolonization and especially the role of the supragingival environment in this process are still not well-understood. This prospective, split-mouth study followed the early colonization of 'pristine' pockets created during implant surgery (16 partially edentulous patients), to record the time needed before a complex subgingival flora could be established with the supragingival area as the single source. Four subgingival plaque samples were taken from shallow and medium pockets around implants (test), and neighboring teeth (undisturbed microbiota as reference) 1, 2, and 4 wks after abutment connection. Checkerboard DNA-DNA hybridization and culture data revealed a complex microbiota (including several pathogenic species) in the pristine pockets within a wk, with a minimal increase in counts up to 4 wks. Analysis of these data demonstrated that, even with the supragingival environment as the single source for colonizing bacteria, a complex subgingival microbiota can develop within 1 wk.

Non-Surgical Periodontal Therapy With Adjunctive Topical Doxycycline: A Double-Masked, Randomized, Controlled Multicenter Study. II. Microbiological Results

BACKGROUND

Topical application of active substances offers an additional option in periodontal therapy. The aim of this study was to examine the influence of the administration of a novel, biodegradable 14% doxycycline gel on microbiological findings, in connection with scaling and root planing.

METHODS

One hundred ten patients in three centers (Frankfurt and Heidelberg, Germany; Nijmegen, The Netherlands) with moderate to advanced periodontitis were evaluated in this randomized, double-masked, split-mouth clinical trial. In each patient, three test teeth were randomly assigned to one of three treatment modalities: 1) scaling and root planing (SRP) alone; 2) SRP with subgingival placebo gel (VEH); or 3) SRP and 14% doxycycline gel (DOX). Subgingival plaque samples were analyzed at baseline and 3 and 6 months after therapy for Actinobacillus actinomycetemcomitans (A.a.), Tannerella forsythensis (T.f.), Porphyromonas gingivalis (P.g.), and Treponema denticola (T.d.) using a RNA probe. Samples from 10 patients were tested for resistance against doxycycline, amoxicillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole using agar diffusion testing.

RESULTS

The largest decrease in pathogens was found after 3 months, with the most pronounced differences between DOX and SRP (P <0.05). At 6 months, pathogens were still reduced markedly in all groups. Treatment results were consolidated for VEH and DOX, with a slight deterioration for SRP (DOX versus SRP: P <0.001). Resistance was observed to amoxycillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole (four isolates) but not to doxycycline.

CONCLUSION

The addition of subgingival instillation of a 14% doxycycline gel resulted in pronounced reduction of periodontal pathogens after 3 months and stabilizing results up to 6 months after therapy. Resistance to doxycycline was not induced.

Antibiotic resistance profile of the subgingival microbiota following systemic or local tetracycline therapy

BACKGROUND

Tetracyclines have been extensively used as adjunctives to conventional periodontal therapy. Emergence of resistant strains, however, has been reported. This study evaluated longitudinally the tetracycline resistance patterns of the subgingival microbiota of periodontitis subjects treated with systemic or local tetracycline therapy+scaling and root planing (SRP).

METHODS

Thirty chronic periodontitis patients were randomly assigned to three groups: SRP+500 mg of systemic tetracycline twice/day for 14 days; SRP alone and SRP+tetracycline fibers (Actsite) at four selected sites for 10 days. Subgingival plaque samples were obtained from four sites with probing pocket depths (PPD)> or =6 mm in each patient at baseline, 1 week, 3, 6 and 12 months post-therapy. Samples were dispersed and diluted in pre-reduced anaerobically sterilized Ringer's solution, plated on Trypticase Soy Agar (TSA)+5% blood with or without 4 microg/ml of tetracycline and incubated anaerobically for 10 days. The percentage of resistant microorganisms were determined and the isolates identified by DNA probes and the checkerboard method. Significance of differences among and within groups over time was sought using the Kruskal-Wallis and Friedman tests, respectively.

RESULTS

The percentage of resistant microorganisms increased significantly at 1 week in the tetracycline groups, but dropped to baseline levels over time. The SRP+Actsite group presented the lowest proportions of resistant species at 6 and 12 months. No significant changes were observed in the SRP group. The predominant tetracycline-resistant species included Streptococcus spp., Veillonela parvula, Peptostreptococcus micros, Prevotella intermedia, Gemella morbillorum and Actinobacillus actinomycetemcomitans (Aa). A high percentage of sites with resistant Aa, Porphyromonas gingivalis and Tanerella forsythensis was observed in all groups at baseline. However, T. forsythensis was not detected in any group and P. gingivalis was not present in the SRP+Actsite group at 1 year post-therapy. Aa was still frequently detected in all groups after therapy. However, the greatest reduction was observed in the SRP+Actsite group.

CONCLUSION

Local or systemically administered tetracycline results in transitory selection of subgingival species intrinsically resistant to this drug. Although the percentage of sites harboring periodontal pathogens resistant to tetracycline were quite elevated in this population, both therapies were effective in reducing their prevalence over time.

Debridement and local application of tetracycline-loaded fibres in the management of persistent periodontitis: results after 12 months

BACKGROUNDS/AIMS

The aim of our study was to evaluate the clinical, radiological and microbiological response to the local delivery of tetracycline (TE) of sites with persistent periodontal lesions.

MATERIALS AND METHODS

The study was conducted in a split-mouth design. Nineteen patients with at least four bilateral pockets 4-5 mm and bleeding on probing (BOP) were treated with scaling and root planing (SRP) plus TE fibres (test sites) or with SRP alone (control sites). Clinical and radiological measurements were taken at baseline, 6 months and 12 months post-operatively. Subgingival plaque samples were collected at baseline, at fibres removal, 6 and 12 months following treatment and analysed by polymerase chain reaction.

RESULTS

Both treatments yielded a statistically significant (p<0.05) reduction of probing depth (2.05 and 1.21 mm), gain of clinical attachment level (1.71 and 0.53 mm) and reduction of BOP scores (23.68% and 57.89%) for TE and SRP groups, respectively, when comparing 12-month data with baseline. The differences between two groups were significant. The prevalence of Treponema denticola and Bacteroides forsythus decreased after therapy in both groups but only in the test sites Actinobacillus actinomycetemcomitans and Prevotella intermedia were not yield detected. The pathogens could be eliminated from five periodontal pockets by SRP alone, while 21 TE sites were not recolonized at 12 months.

CONCLUSIONS

SRP plus TE fibres gave the greatest advantage in the treatment of periodontal persistent lesions at least 12 months following treatment.

Microbial shifts after subgingival debridement and formation of bacterial resistance when combined with local or systemic antimicrobials

Antibiotics have played a major role in the improvement of life expectancy in the last 50 years and have led many to believe that bacterial infections were about to vanish as a disease entity of any importance. Emerging problems resulting from a widespread use of antibiotics have modified the general perception of the capabilities of antimicrobial agents. Over the years, bacteria have become increasingly resistant to formerly potent antimicrobial agents, including some antiseptics. The use of antimicrobials may also disturb the delicate ecological equilibrium of the body, allowing the proliferation of resistant bacteria or non-bacterial micro-organisms. This shift may initiate new infections that are worse than the ones originally treated. No antimicrobial drug is absolutely non-toxic and the use of an agent carries accompanying risks. This paper discusses the development and occurrence of antimicrobial resistance in the subgingival flora towards antiseptics and local or systemic antibiotics and is focussed on the question: how can the outcome of periodontal therapy with/without antimicrobials be improved?

Subgingival plaque removal in buccal and lingual sites using a novel low abrasive air-polishing powder

AIM OF THE STUDY

This study was aimed at assessing the efficacy of subgingival plaque removal in buccal and lingual sites during supportive periodontal therapy (SPT) using a novel low abrasive air-polishing powder.

MATERIAL AND METHODS

In 27 SPT patients, subgingival debridement was performed using the novel air-polishing powder (test) and hand instruments (positive control) in a randomized split mouth design. Before and immediately after treatment, subgingival plaque samples were taken from two teeth with pockets of 3-5 mm depth in both groups. To assess the influence of plaque sampling on the microflora, samples were also taken twice from two untreated teeth (negative control). The mean reduction in total colony forming units (CFU) was assessed by anaerobic culture. The patients' perception of treatment was assessed by a visual analog score (VAS). Therapy and plaque sampling were repeated after a 3-month interval.

RESULTS

Test treatment resulted in a significantly greater reduction in mean CFU than positive control treatment (log 1.7+/-0.98 and log 0.61+/-0.79 respectively; p<0.05). Following both treatments, the CFU reduction was significantly greater compared to negative control treatment (log 0.06+/-0.49; p<0.05). In addition, test treatment was perceived as significantly more pleasant than hand instrumentation (p<0.05).

CONCLUSION

The novel low abrasive air-polishing powder is superior to curettes in removing subgingival plaque from pockets of 3-5 mm depth in supportive periodontal therapy and offers greater patient comfort.

Antimicrobial effects of mechanical debridement

Self-performed plaque removal using manual or powered toothbrushes and interdental cleaning devices is improved in subjects that have received oral hygiene instructions. Personal oral hygiene coupled with regular professional supragingival debridement may further improve the level of plaque control but still fails to achieve a completely plaque-free dentition. Both patient-performed and professional supragingival plaque removal has an effect on subgingival microbiota that is limited to the marginal 3 mm of the periodontal pocket. At sites with 4 mm or more of probing depth, only subgingival scaling leads to a significant reduction of the bacterial load. The subgingival microflora can be further reduced by pocket elimination surgery. Due to the sequence of bacterial recolonization that occurs following mechanical debridement, the level of periodontal pathogens such as B. forsythus, P. gingivalis and T. denticola may be reduced for several months. Mechanical debridement also influences the patient's immune system response, resulting in antibody titers and avidity against periodontal pathogens. As a basis for the restoration and maintenance of periodontal health, repeated subgingival debridement, as performed in supportive periodontal therapy, can reduce the number and proportions of periodontopathogenic bacteria in subgingival plaque. However, intensive subgingival scaling and root planing should be avoided in sites that probe less than 3 mm, as this is likely to traumatize the periodontium and cause attachment loss.

Effective, safe, practical and affordable periodontal antimicrobial therapy: where are we going, and are we there yet?

Several important trends are noticeable in the management of periodontal disease. Searching for specific risk factors for periodontal disease permits therapy planning with the intention of doing less for low-risk patients and increasing the preventive and therapeutic modalities for high-risk patients. Also, significant progress in the area of chemotherapeutic development enables dentists to increase the number of periodontitis patients receiving nondisruptive antimicrobial therapy and decreases the need for surgical treatment. Use of anti-infective chemotherapeutic and antibiotic agents has become a specialized and increasingly effective means of preventing and treating destructive periodontal disease. Local care, including subgingival application of some type of antiseptics, is widely accepted. The use of systemic antibiotics is not routine and should be reserved for aggressive and refractory periodontal infections. In general, it is better to be thoroughly familiar with a limited number of drugs and treatment methods and use them properly than to try to master a plethora of antimicrobial therapies. Combating periodontal infections is best accomplished by combined mechanical and chemotherapeutic efforts of the dental professional and the patient. The trend during recent years has been to treat periodontal infections aggressively, employing short-course antimicrobial therapy using a battery of safe and affordable antimicrobial agents, each exhibiting high activity against various periodontal pathogens and administered in ways to concurrently affect pathogens residing in different oral ecological niches, followed by regular maintenance visits having a strong anti-infective emphasis. At the beginning of therapy, patients should be assigned self-help tasks having maximal antimicrobial effectiveness, with a focus on control of the subgingival periodontopathic microbiota. When patients see positive clinical results from their daily oral hygiene efforts, they are motivated to remain active participants in managing their periodontal condition. This article emphasizes anti-infective periodontal therapies that are effective and, when properly administered, are essentially nontoxic; are widely available around the world to dentists as well as to patients; and are acceptable to most patients in terms of methods of application, supporting oral hygiene efforts and financial costs. We believe that, with improved knowledge of the periodontopathic microbiota, with the availability of microbiological tests to identify periodontal pathogens and optimal therapy, with various safe and affordable yet effective antimicrobial agents and therapies and, eventually, with the development of one or more effective vaccines, the future looks very bright for patients at risk for or suffering from destructive periodontal disease.

Changes in subgingival microflora and humoral immune response following periodontal therapy

OBJECTIVES

To investigate the effect of scaling and root planing (SRP) on the microflora and humoral immune response in adult periodontitis.

MATERIALS & METHODS

Clinical measurements, subgingival plaque samples, gingival crevicular fluid and sera were taken from 4 sites in 28 adult periodontitis patients before and after SRP. Polymerase chain reaction was used to determine the presence of A. actinomycetemcomitans, P. gingivalis, B. forsythus, P. intermedia, and T. denticola. ELISA was used to investigate the systemic and local antibody titres to these organisms, and thiocyanate dissociation for the determination of serum antibody avidity.

RESULTS

SRP produced a good clinical improvement. On a subject basis there was little significant change in the microflora. However, on a site basis, there were significant reductions in P. intermedia, B. forsythus and T. denticola. There was little change in systemic and local antibody titres following SRP, although there was a significant reduction in antibody avidity to P. gingivalis and P. intermedia

CONCLUSION

Post-therapy clinical improvement was associated with a reduction in bacterial prevalence, but statistical significance was only reached at a site level and this microbial reduction was not significant for all organisms. No significant post-therapy effects on the humoral immune response were noted other than a reduced antibody avidity to P. gingivalis and P. intermedia. The lack of a clear pattern in the humoral immune response may reflect a failure of the host response to produce adequate levels of biologically functional antibodies, and complex interactions between the subgingival flora and the host response.

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.

Microbiological response of localized sites with recurrent periodontitis in maintenance patients treated with tetracycline fibers

BACKGROUND

Whether adjunctive tetracycline fibers can provide an additive effect to scaling and root planing in treating non-responsive sites in maintenance subjects is still controversial. Recolonization of the bacteria from untreated sites or from the extracrevicular region may explain the insignificant response to local therapy. The purpose of the present study was to evaluate the microbiological response of sites treated with tetracycline fibers combined with scaling and root planing.

METHODS

The study was conducted in a split-mouth design. Thirty patients on maintenance therapy having at least 2 non-adjacent sites in separate quadrants with probing depths between 4 to 8 mm with bleeding on probing, or aspartate aminotransferase enzyme levels > 800 microIU in the gingival crevicular fluid, were treated with scaling and root planing plus tetracycline fibers or with scaling and root planing only. Subgingival plaque samples were collected at baseline, and 1, 3, and 6 months following treatment. A. actino-mycetemcomitans, C. rectus, B. forsythus, E. corrodens, F. nucleatum, P. gingivalis, and P. intermedia were detected by culture, immunofluorescence, or PCR technique.

RESULTS

There was a reduction of total bacterial cell count, as well as of certain periodontal pathogens, following treatment. The prevalence of A. actinomycetemcomitans, B. forsythus, and P. gingivalis and the mean proportions of C. rectus, P. intermedia, F. nucleatum, and P. gingivalis decreased after therapy, but there was no statistically significant difference between the 2 treatment groups with respect to bacterial proportions or the number of positive sites. Besides, the pathogens could not be eliminated from the periodontal pocket, and recolonization of the pocket was noted at 3 months post-treatment.

CONCLUSIONS

Bacteria located within the cheek, tongue mucosa, saliva, or untreated sites may contribute to reinfection of the pockets and explain the insignificant response to local tetracycline therapy.

Local delivery of tetracycline: from concept to clinical application

This manuscript reviews the development over the last 20 years of the evidence supporting the clinical application of a controlled delivery device for the treatment of human periodontitis. The device is a monolithic ethylene vinyl-acetate fibre loaded with 25% w/w tetracycline HCI (tetracycline fibre). It releases tetracycline at a steady state rate of 2 microg/cm x h and results in the maintenance of essentially constant, highly-effective concentrations of tetracycline at the site of action. A series of controlled, randomised, single-blind, phase-III clinical trials including a total of 463 patients has indicated that: (1) tetracycline fibres result in significantly better outcomes than the scaling and root planing positive control; (2) combination of tetracycline fibres with subgingival mechanical debridement results in significant improvement over debridement alone. Evidence from these studies has led to approval of this treatment modality by the US Food and Drug Administration and by the European Union Regulatory Bodies. A clinical usage study involving 2711 subjects treated by 68 clinicians in Europe and North America indicated that the magnitude of the observed clinical outcomes is clinically relevant and that adverse events were rarely observed. A variety of clinical investigations aimed at the optimal incorporation of tetracycline fibres in a treatment strategy provide guidance in case selection. Cost of therapy and concerns of unnecessary usage of antibiotics should be considered. It is nonetheless concluded that combination of tetracycline fibres with mechanical debridement represents a documented treatment alternative, the application of which may offer clinical benefits to many patients.

The role of local drug delivery in the management of periodontal diseases: a comprehensive review

This review article evaluates the role of local drug delivery systems in the management of periodontal diseases. The efficacy of several local delivery devices (i.e., tetracycline fibers, metronidazole and minocycline gels, chlorhexidine chips, and doxycycline polymer) which are either commercially available in the United States or abroad, or are currently under consideration for Food and Drug Administration (FDA) approval are discussed. The drug delivery systems are assessed with regard to their functional characteristics, effectiveness as a monotherapy, as compared to scaling and root planing, and ability to enhance conventional therapy. Furthermore, controversies associated with local delivery are addressed (e.g., induction of bacterial resistant strains, the efficacy of systemic versus local drug delivery, and whether local drug delivery should function as an alternative or as an adjunct to conventional treatment).

Rapid chair-side DNA probe assay of Bacteroides forsythus and Porphyromonas gingivalis

This study compared a rapid, colorimetric DNA probe assay designed to be performed in a dental office within 40 min, with anaerobic culture and indirect immunofluorescence microscopy (IFM) for detection of Bacteroides forsythus and Porphyromonas gingivalis in subgingival plaque samples. The DNA probe assay used the Periodontal Microbial Identification Test (Saigene Corporation, Bothell, Washington, USA). B. forsythus was detected in 46 (52%), 49 (55%) and 39 (44%) of the samples by DNA probe, culture (at levels > or = 10(5)) and IFM, respectively. P. gingivalis was detected in 24 (27%), 18 (20%) and 29 (33%) of the samples by DNA probe, culture (at levels > or = 10(5)) and IFM, respectively. Results from the DNA probe assay were compared to culture. Culture negative, probe positive samples were re-evaluated by IFM, and IFM positive samples were considered positive in "resolved" data. Using resolved data. DNA probe detection sensitivity and specificity values for B. forsythus were 81% and 91% and for P. gingivalis were 80% and 95%, respectively. DNA probe test results were further compared with culture and IFM. For samples negative by both culture and IFM, probe specificity was 92% in 25 B. forsythus samples and 95% in 57 P. gingivalis samples. For samples positive by both reference methods, probe sensitivity was 82% in 27 B. forsythus samples and 73% in 15 P. gingivalis samples. B. forsythus was detected more frequently by culture compared with IFM; the reverse was observed for P. gingivalis. The rapid DNA probe assay for B. forsythus and P. gingivalis was comparable to cultivable and IF analyses.

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.

Adjunctive controlled topical application of tetracycline HCl in the treatment of localized persistent or recurrent periodontitis. Effects on clinical parameters and elastase-alpha1-proteinase inhibitor in gingival crevicular fluid

35 patients receiving regular supportive periodontal therapy (SPT) and showing signs of localized persistent or recurrent periodontitis were enrolled in the study. Within 1 week after SPT, each patient had a tetracycline HCl loaded ethylene vinyl acetate co-polymer fiber placed into the periodontal pocket of 1 randomly selected tooth with persistent or recurrent periodontitis (test); the fiber was removed after 9.5+/-2.0 days. A non-adjacent tooth with persistent or recurrent periodontitis in a separate quadrant, which received no further treatment, served as a control. A total of 28 patients completed the 6-month study. Compared to control teeth, in test teeth at 6 months significantly (p<0.01) lower scores were found for gingival index, pocket probing depths, and PMN elastase-alpha1-proteinase inhibitor concentrations in gingival crevicular fluid. With the exception of plaque index scores, test teeth demonstrated significant reductions from baseline to 6 months in all parameters (p<0.05). Conversely, all parameter measurements in control teeth, except bleeding on probing, showed no significant difference between baseline and 6-month values. The results suggest that the use of controlled topical application of tetracycline HCl may improve periodontal health and reduce the risk of disease progression in localized persistent or recurrent periodontitis. Moreover, the effects of this application appear to be sustained for at least 6 months.

Taxonomy, biology, and periodontal aspects of Fusobacterium nucleatum

The pathogenic potential of Fusobacterium nucleatum and its significance in the development of periodontal diseases, as well as in infections in other organs, have gained new interest for several reasons. First, this bacterium has the potential to be pathogenic because of its number and frequency in periodontal lesions, its production of tissue irritants, its synergism with other bacteria in mixed infections, and its ability to form aggregates with other suspected pathogens in periodontal disease and thus act as a bridge between early and late colonizers on the tooth surface. Second, of the microbial species that are statistically associated with periodontal disease, F. nucleatum is the most common in clinical infections of other body sites. Third, during the past few years, new techniques have made it possible to obtain more information about F. nucleatum on the genetic level, thereby also gaining better knowledge of the structure and functions of the outer membrane proteins (OMPs). OMPs are of great interest with respect to coaggregation, cell nutrition, and antibiotic susceptibility. This review covers what is known to date about F. nucleatum in general, such as taxonomy and biology, with special emphasis on its pathogenic potential. Its possible relationship to other periodontal bacteria in the development of periodontal diseases and the possible roles played by OMPs are considered.

Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Treponema denticola detection in oral plaque samples using the polymerase chain reaction

Detection of putative pathogens is critical for delineating the etiology and progression of periodontitis. In the present study, we have used a polymerase chain reaction (PCR) assay utilizing primers specific for the lkt A gene of Actinobacillus actinomycetemcomitans, the fimbrial gene of Porphyromonas gingivalis, and tdp A gene of Treponema denticola in order to determine the presence of these pathogens in subgingival plaque samples from periodontitis sites. These gene specific primers were also used to assess the detection of different strains of bacteria in the PCR assays. Primers for P. gingivalis detected P. gingivalis strain 33277, but no product was detected when primers were used with extracts from 4 species of Capnocytophaga, 3 species of Prevotella, 2 species of Porphyromonas other than P. gingivalis, Bacteroides levii, Escherichia coli, 3 strains of A. actinomycetemcomitans and 3 strains of T. denticola. PCR analysis using primers for the lkt A gene of A. actinomycetemcomitans also did not result in a product with any of these bacteria with the exception of a positive result with 3 different strains of A. actinomycetemcomitans. Primers selected from the tdp A gene of T. denticola did not identify any of the bacteria strains tested except T. denticola serovars a, b, and c. Thus, these primers were shown to amplify gene segments that are specific to either P. gingivalis (33277), A. actinomycetemcomitans (33384, 43717 and 43718) or T. denticola (35405, 33521 and 35404). The PCR assay may be used to rapidly detect the presence of periodontal pathogens in the future.

Taxonomy, biology, and periodontal aspects of Fusobacterium nucleatum

The pathogenic potential of Fusobacterium nucleatum and its significance in the development of periodontal diseases, as well as in infections in other organs, have gained new interest for several reasons. First, this bacterium has the potential to be pathogenic because of its number and frequency in periodontal lesions, its production of tissue irritants, its synergism with other bacteria in mixed infections, and its ability to form aggregates with other suspected pathogens in periodontal disease and thus act as a bridge between early and late colonizers on the tooth surface. Second, of the microbial species that are statistically associated with periodontal disease, F. nucleatum is the most common in clinical infections of other body sites. Third, during the past few years, new techniques have made it possible to obtain more information about F. nucleatum on the genetic level, thereby also gaining better knowledge of the structure and functions of the outer membrane proteins (OMPs). OMPs are of great interest with respect to coaggregation, cell nutrition, and antibiotic susceptibility. This review covers what is known to date about F. nucleatum in general, such as taxonomy and biology, with special emphasis on its pathogenic potential. Its possible relationship to other periodontal bacteria in the development of periodontal diseases and the possible roles played by OMPs are considered.

Evaluation of periodontal treatments using controlled-release tetracycline fibers: microbiological response

In a 12-month multi-center study of 116 adult periodontitis subjects, six putative periodontal pathogens were monitored by DNA probe methods in a subset of 31 subjects. Monitored species included Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), Eikenella corrodens (Ec), Campylobacter rectus (Cr), and Actinobacillus actinomycetemcomitans (Aa) with an average detection limit of 1.8 x 10(4) bacterial colony forming units/sample. The microbiological response to four periodontal treatments was studied, one treatment in each quadrant; scaling and root planing (S), scaling and root planing with tetracycline (TC) fiber (SF), a single application of TC fiber (F) and two serial applications of TC fiber (FF). Generally two sites were sampled in each quadrant, however, in some quadrants only one site was selected. These treatments were evaluated at baseline; immediately following therapy; and post-treatment at 1, 3, 6, and 12 months. The study was conducted with a split-mouth design with no maintenance therapy over a 12-month period. At baseline, 70.8% of sites had detectable Fn; 42.9% Pg; 63.5% Pi; 29.7% Ec; 28.3% Cr; and 5.5% Aa. No significant differences were seen in baseline proportions of these species between centers. Numbers and proportions of detectable pathogens (with the exception of Pg) exhibited a triphasic temporal response: a precipitous initial decrease immediately following therapy; a rise in proportions in the 1- to 3-month post-therapy period; and a spontaneous decline in the absence of therapy over the 3- to 12-month period.(ABSTRACT TRUNCATED AT 250 WORDS)

Tetracyclines in the management of periodontal diseases. A review

Periodontal diseases essentially comprise a group of oral infections whose primary aetiological factor is dental plaque. Removal of the cause (and its effects) is the primary aim of both non-surgical and surgical treatment regimens, although the infective nature of the diseases has led to the widespread use of antimicrobials as an adjunct to mechanical debridement. The tetracyclines are primarily bacteriostatic agents that are effective against many Gram-negative species including putative periodontopathogens such as Actinobacillus actinomycetemcomitans (A.a.). The proven efficacy of this group of drugs in the management of periodontal diseases may be related not only to their antibacterial actions, but to a number of additional properties that have been recently identified. These include collagenase inhibition, anti-inflammatory actions, inhibition of bone resorption and their ability to promote the attachment of fibroblasts to root surfaces. Consequently, tetracyclines have also been used as an adjunct to bone grafting in periodontal defects, and as agents for 'conditioning' root surfaces to enhance the regeneration of periodontal tissues. When tetracyclines are taken orally, consideration must be given both to the potential unwanted effects and to interactions with other drugs that are taken concurrently. Such problems are minimised however, when the drugs are incorporated into controlled, slow-release formulations which are currently being researched and marketed for intra-oral use.

Clinical and microbiological effects of controlled-release locally delivered minocycline in periodontitis

The clinical efficacy of minocycline in a subgingival local delivery system was evaluated alone (M) or as an adjunct to scaling and root planing (M + SRP), in comparison to scaling and root planing (SRP) or to no subgingival treatment (NoTx) in adult periodontitis. Fifty-one adult patients with > or = 7 mm periodontal pockets demonstrating the presence by culture of Porphyromonas gingivalis (Pg), Prevotella intermedia (P(i)), or Actinobacillus actinomycetemcomitans (Aa) were randomized into one of the above 4 treatment groups. All sites > or = 5 mm in the most diseased quadrant in each patient received the therapy. Other quadrants were not treated. All patients received standardized oral hygiene instructions at the beginning of the study. At 0, 1, 3 and 6 months following therapy the 7 mm experimental sites were evaluated for selected periodontal pathogens by DNA probe analysis. At these same time points, the plaque index, gingival index, and bleeding on probing were evaluated as well as probing depth and relative clinical attachment level which were assessed by means of an automated probe. Probing depth reduction with M + SRP was significantly greater than all other groups at one month and significantly greater than NoTx and SRP at 3 months. There were no differences in probing depth reduction among groups at 6 months. At 6 months the gain in clinical attachment level was significantly greater for SRP than for either the NoTx or M groups. The prevalence of Pg decreased significantly in the M and M + SRP groups at one month.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous hybridization and subsequent colour detection of subgingival bacterial DNA on colony lifts

This paper reports the development of a protocol allowing hybridization and detection of DNA fixed to nylon colony lifts from up to three species of bacteria simultaneously. Half ml samples of serial dilutions of pure cooked-meat broth (CMB) cultures of Capnocytophaga ochracea, Actinobacillus actinomycetemcomitans and Prevotella intermedia were grown on trypticase soy blood agar (TSBA) plates for 7 days in an anaerobic chamber. From the same CMBs a further set of dilutions was completed that contained all three species. Samples from these dilutions produced mixed-growth TSBA plates following anaerobic incubation for 7 days. After incubation, colony counts on pure-growth TSBA plates were enumerated by colony counter. Colony counts of C. ochracea, A. actinomycetemcomitans and P. intermedia on mixed-growth TSBA plates were enumerated by nylon colony lift, simultaneous hybridization with non-isotopic whole chromosomal DNA probes and alkaline phosphatase substrates generating three colours. The results indicate that the protocol correctly identified and differentiated between the three species on mixed-growth TSBA plates. The proportions of each species and mean total colony count expected by counting pure plates were in agreement with the proportions of each species and total colony counts enumerated by DNA probes on mixed growth plates. The development of simultaneous hybridization and multicolour detection will result in improved data recovery from dental plaque samples, in addition to reducing the cost and labour required in current colony-lift protocols, without affecting the specificity or sensitivity of the probes used.

An in vivo study of the influence of the surface roughness of implants on the microbiology of supra- and subgingival plaque

In nine patients with fixed prostheses supported by endosseous titanium implants, 2 titanium abutments (transmucosal part of the implant) were replaced by either an unused standard abutment or a roughened titanium abutment. After 3 months of habitual oral hygiene, plaque samples were taken for differential phase-contrast microscopy, DNA probe analysis, and culturing. Supragingivally, rough abutments harbored significantly fewer coccoid micro-organisms (64 vs. 81%), which is indicative of a more mature plaque. Subgingivally, the observations depended on the sampling procedure. For plaque collected with paper points, only minor qualitative and quantitative differences between both substrata could be registered. However, when the microbiota adhering to the abutment were considered, rough surfaces harbored 25 times more bacteria, with a slightly lower density of coccoid organisms. The presence and density of periodontal pathogens subgingivally were, however, more related to the patient's dental status than to the surface characteristics of the abutments. These results justify the search for optimal surface smoothness for all intra-oral and intra-sulcular hard surfaces for reduction of bacterial colonization and of periodontal pathogens.

Identification of Bacteroides forsythus in subgingival plaque from patients with advanced periodontitis

Bacteroides forsythus has been associated with destructive adult periodontitis. Up to now, detailed analysis by classical means was hampered by the fastidious nature of the organism. There is hope that the application of molecular detection methods such as indirect immunofluorescence or in situ hybridization (ISH) will allow for more rapid and accurate identification. Here we describe a B. forsythus-specific probe (BFV530), complementary to 16S rRNA, which correctly identified all B. forsythus isolates as confirmed by biochemical, protein, or fatty acid analysis. To assess whether this probe might be suitable for direct identification of B. forsythus in clinical specimens, a total of 92 subgingival plaque samples were analyzed. Fifty-five specimens were tested in parallel by culture, light microscopy, and filter hybridization. Unfortunately, the overall agreement between results of filter hybridization and conventional methods was 70.9% only. We therefore examined 37 new specimens by ISH and indirect immunofluorescence by using fluorescently labeled probe BFV530 or B. forsythus-specific monoclonal antibody 116BF1.2 (kindly provided by R. Gmür, Zurich, Switzerland), respectively. Agreement between these methods was 100%, indicating that ISH with probe BFV530 might be used to accurately identify B. forsythus directly in subgingival plaque samples.

Design issues specific to studies of periodontitis

Guidelines for clinical trials demonstrating equivalence or superiority for treatments for periodontitis are badly needed because of the great variety of drugs, agents, and devices now being developed. This paper focuses on three design issues. These are primary outcome variables and their measurement, disease-active vs disease-inactive sites and patients, and study duration. Determinants for selection of outcome variables include the biologic events to be observed, changes that are specific for periodontitis, and methods chosen to detect those changes. The primary outcome variables specific for periodontitis and appropriate for use in clinical trials are periodontal attachment level and alveolar bone status. Improved methods for measurement of both with excellent accuracy and reproducibility are now becoming available. Studies performed on untreated patients over the past decade demonstrate clearly that disease-active and disease-inactive pockets exist, at any given point in time most are inactive, disease progression is episodic and in most patients infrequent, and a rather small portion of the population--possibly around 5%--are unusually susceptible to rapid disease progression. These observations need to be taken into account in enrolling subjects into periodontitis clinical trials. Conducting a prestudy to identify actively diseased sites and susceptible subjects, or screening to enrich the proportion of active sites, is recommended. Determination of study duration is a very complex issue. It is related to the length of time required for maximal change and stabilization to occur in the biological events to be observed, the outcome variable(s) used to detect change, and the nature of the therapeutic interventions to be studied. No single duration is applicable to all periodontitis clinical trials. Large gaps in our knowledge about the design of periodontitis trials still exist, and additional research is needed.

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

The committee screened several hundred articles, citing 518 published papers. Some are present quality in research, others provide clinical interest, and some are identified as misleading. New techniques in pulp physiology and pathology are reported. Laser use and techniques in prevention, restorative dentistry, and materials use are reported. Epidemiology of selected diseases and the results of various formulations for treatment are cited. Diagnosis of craniomandibular dysfunction is well represented as well as references to literature reviews and other sophisticated scientific investigation. Research on adhesives is presented in respect to bonding agents for dentin and enamel. Several clinical studies are included, along with customary laboratory reports on several materials.