Clinical effects of local application of collagen film-immobilized tetracycline

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 Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries. First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided. The advances and shortfalls of various collagen preparations (e.g., mammalian/marine extracted collagen, cell-produced collagens, recombinant collagens, and collagen-like peptides) and crosslinking technologies (e.g., chemical, physical, and biological) are then critically discussed. Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures. Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (e.g., tissue grafts, biomaterials, cell-assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules. Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice.

Controlled and targeted drug delivery strategies towards intraperiodontal pocket diseases

Advances in the understanding of the aetiology, epidemiology, pathogenesis and microbiology of periodontal pocket flora have revolutionized the strategies for the management of intraperiodontal pocket diseases. Intra-pocket, sustained release, drug delivery devices have been shown to be clinically effective in the treatment of periodontal infections. Several degradable and non-degradable devices are under investigation for the delivery of antimicrobial agents into the periodontal pocket including non-biodegradable fibres, films (biodegradable and non-biodegradable), bio-absorbable dental materials, biodegradable gels/ointments, injectables and microcapsules. With the realization that pocket bacteria accumulate as biofilms, studies are now being directed towards eliminating/killing biofilm concentrations rather than their planktonic (fluid phase) counterparts. Intraperiodontal pocket drug delivery has emerged as a novel paradigm for the future research. Similarly, bioadhesive delivery systems are explored that could significantly improve oral therapeutics for periodontal disease and mucosal lesions. A strategy is to target a wide range of molecular mediators of tissue destruction and hence arrest periodontal disease progression. Research into regenerating periodontal structures lost as a result of disease has also shown substantial progress in the last 25 years.

Subgingival controlled release of antimicrobial agents in the treatment of periodontal disease

Local drug delivery of antimicrobics by sustained release delivery systems can be used to treat periodontal disease. Advantages of these systems may include biodegradation of the system, maintaining high levels of antibiotic in the gingival crevicular fluid (GCF) for a sustained period of time and ease of use with high patient acceptance. This review will identify human in vivo clinical and microbiological studies. Sustained release formulations, application methods, clinical results and microbiological effects are discussed.

Clinical and microbiological effects of minocycline-loaded microcapsules in adult periodontitis

Clinical and microbiological effects of subgingival delivery of 10% minocycline-loaded (MC), bioabsorbable microcapsules were examined in 15 adult periodontitis patients. Patients received oral hygiene instruction 2 weeks prior to the study. At baseline (day 0) all teeth received supragingival scaling (SC); 2 quadrants received no further treatment and 1 quadrant received subgingival scaling and root planning (SRP). In the fourth quadrant, the tooth with the deepest probing sites (at least 1 site > or = 5 mm) was treated with minocycline microcapsules. The sites were evaluated at baseline and weeks 1, 2, 4, and 6. Clinical indices included bleeding on probing (BOP), probing depths (PD), and attachment loss (AL). Microbiological evaluations included percent morphotypes by phase-contrast microscopy; cultivable anaerobic, aerobic, and black-pigmented Bacteroides (BPB); and percent Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Actinomyces viscosus by indirect immunofluorescence. In the SC + MC group, BOP, PD, and AL were significantly reduced from baseline for weeks 1 to 6. BOP in the SC + MC group was significantly reduced compared to the SRP group from weeks 2 to 6. In the SC + MC group the percent of spirochetes and motile rods decreased and the percent of cocci increased after 1 week. The increased cocci and decreased motile rods were statistically greater at weeks 4 and 6 in the SC + MC group compared to the SRP group. This study demonstrates that local subgingival delivery of 10% minocycline-loaded microcapsules as an adjunct to scaling results in reduction in the percent sites bleeding on probing greater than scaling and root planning alone and induces a microbial response more favorable for periodontal health than scaling and root planing.

Subgingival delivery of therapeutic agents in the treatment of periodontal diseases

This article reviews the current status of controlled local delivery of antibacterial agents in the treatment of periodontitis. The principle of local intrapocket delivery of antibacterial agents and their delivery are discussed. The dosage forms include fibers, film/slabs, and injectable systems, some of which are degradable, while others are not and need to be removed at the termination of the treatment. The antibacterial agents used cover a range of antibiotics as well as antiseptics, and the composition of the delivery systems, their reported use, and the clinical results are summarized. The use of these systems in clinical practice is relatively recent, and therefore their application and integration into the dental office are not yet clearly defined. Clinical applications that have been tested are critically reviewed, and clinical situations in which controlled delivery of antibacterial agents may prove to be clinically useful are suggested for scientific evaluation.

Periodontal pocket treatment in beagle dogs using subgingival doxycycline from a biodegradable system. I. Initial clinical responses

The present study evaluated the clinical response of periodontal pockets in beagle dogs after treatment with a biodegradable delivery system containing 10% doxycycline hyclate (ABDS-D). Eight adult, female beagle dogs had generalized, severe periodontitis with plaque and calculus-laden pockets. In each animal, 3 teeth with multiple pocket sites > or = 4 mm (mean depth = 6.0 mm) associated with attachment loss (mean = 5.4 mm) and which bled on probing (mean score = 2.5) were treated with a single application of either ABDS-D (experimental group) or the delivery system alone without the doxycycline (control group). Residual polymer was removed at day 7. Bioassay of doxycycline in gingival crevicular fluid associated with presence of ABDS-D gave mean levels of bioactivity of approximately 250 micrograms/ml. Levels of bioactive doxycycline were detected for approximately 7 days after ABDS-D removal. Periodontal maintenance consisted of thrice-weekly toothbrushing the treated sites. Clinical responses were evaluated at 2 weeks, and at bi-weekly intervals thereafter for 4 months. Analyses of the data from the control group showed that there was only slight clinical improvement. In contrast, in the experimental group, bleeding on probing and probing depths were significantly reduced from baseline at all post-treatment time points. At 1 month, mean probing depth reduction was 2.4 mm and this was maintained at 4 months (mean reduction = 2.5 mm). These probing depth reductions occurred primarily through gain of clinical attachment which was 2.0 mm at 4 months. Bleeding had been virtually eliminated (mean = 0.2). It was concluded that, for the beagle dogs with severely infected periodontal pockets in this study, treatment with subgingival doxycycline using the delivery system resulted in substantial improvement in periodontal health.

Microbial flora in the acute phase of periodontitis and the effect of local administration of minocycline

Periodontitis, similar to other infectious diseases, is known to progress as chronic inflammation with recurrent acute phases. The purpose of this study was to clarify the microbiological composition of the acute phase and to compare the bacterial flora with that of comparable chronic periodontal pockets. We also evaluated the effect of application of minocycline gel locally on the change in the microflora in the acute pockets. Microbial flora from the subgingival pockets of 28 patients in the acute phase of periodontitis and of 12 patients in a comparable chronic phase as the control were investigated by various bacterial culture methods including TS blood agar and TSBV plates. Minocycline gel was applied to the acute periodontal pockets. Changes in the microbiological proportion and clinical parameters at one week after baseline examination were followed by dark-field analysis, culture method, and indirect immunofluorescence technique. Characteristic features of bacterial proportions in the acute site were observed as an increase in Bacteroides forsythus. The number of Porphyromonas gingivalis and black pigmented anaerobic rods also increased. Application of minocycline gel in the acute pocket without any debridement produced improvement in clinical symptoms at one week. Black-pigmented anaerobic rods, P. gingivalis, and B. forsythus decreased significantly at one week after the application. Results indicate that periodontopathic bacteria including B. forsythus and P. gingivalis were predominant in the acute phase of periodontitis and a locally delivered antibiotic may be effective as an alternative modality of treating the acute inflammation.

Topical application of tetracycline-HCl in human periodontitis

Previous in vitro studies have suggested that tetracycline-HCl (TTC-HCl) is adsorbed and actively released from root dentin. The aim of the current study was to evaluate the binding to and release of TTC-HCl from human root dentin surfaces in vivo, and to evaluate the clinical utility of TTC-HCl irrigation as an adjunct to scaling and root planing. Experiment I utilized two contralateral mandibular single-rooted teeth which were examined in four adults with severe generalized periodontitis. One tooth in each patient was carefully scaled and root planed, under local anesthesia, and the other used as an unscaled control. Each subgingival root surface was irrigated for 5 min with an aqueous TTC-HCl solution at a concentration of 100 mg/ml. Gingival crevicular fluid samples were collected on paper strips for the next three weeks. The TTC-HCl concentrations in each sample were determined by the inhibition zone of B. cereus cultured on agar plates. The TTC-HCl concentrations in gingival crevicular fluid collected 15 min after irrigation were 3100 +/- 670 micrograms/ml from the scaled lesions and 4700 +/- 1300 micrograms/ml from the unscaled root surfaces. The antibiotic concentrations decreased logarithmically over the next 7 days; 1500 +/- 270 micrograms/ml and 1100 +/- 330 micrograms/ml at 2 h, 880 +/- 350 micrograms/ml and 1300 +/- 360 micrograms/ml at 6 h and 19 +/- 5 micrograms/ml and 31 +/- 26 micrograms/ml at 1 week for scaled and unscaled root surfaces, respectively. Results for week two and three indicated an average of over 8 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of addition of antimicrobial drugs to human collagen membrane

Antimicrobial agents included in graft material for use in guided tissue regeneration of periodontally diseased tissue may be of value in combating infection, but may also alter the properties of the membrane material and exert an effect upon the host immune response. Metronidazole, niridazole and tinidazole were added to a cross-linked freeze-dried human type I collagen membrane in various doses and the following measured: (i) daily drug release into an aqueous solution, (ii) minimum inhibitory concentration (MIC) of the drugs against periodontopathogens, (iii) the effect of the drugs on mechanical properties of the membrane, and (iv) degradation by bacterial collagenase. In addition, the effects of the drugs on in-vitro cellular response was assessed by measuring blastogenesis of mononuclear cells obtained from patients suffering from periodontal disease and age/sex matched controls following incubation with the periodontopathogen Actinobacillus actinomycetemcomitans (AaY4). It was found that the collagen membranes released high levels of the drugs, at concentrations well above the MIC values. The mechanical properties of the membranes were not affected by the addition of the drugs, although resistance to the collagenases were. The cellular immune response was likewise suppressed in both patient and controls at drug doses comparable with the in-vitro drug release patterns. It is concluded that incorporation of antimicrobial drugs in a collagen barrier membrane may be of value when used in guided tissue regeneration.

Concentration of metronidazole in periodontal pockets after application of a metronidazole 25% dental gel

The metronidazole concentration was monitored in gingival crevicular fluid (GCF) of inflamed periodontal pockets after 1 application of a 25% gel. 12 patients with periodontal disease were included in the study. Metronidazole gel was applied with a syringe into the pockets of 10 teeth with probing depths > or = 5 mm. Samples of GCF were taken with Periopaper before application and 4, 8, 12, 24 and 36 h after application. At each time, samples from 2 teeth were pooled in order to obtain a sufficient amount of fluid for analysis. By means of a calibrated Periotron, the collected volume of GCF was measured. High-performance liquid chromatography was used to determine the amount of metronidazole. MIC50 for anaerobic periopathogens susceptible to metronidazole is below 1 microgram/ml. In this study, the concentration obtained was higher than 1 microgram/ml in all samples after 4 and 8 h, in 92% after 12 h, in 50% after 24 h and in 8% after 36 h. Thus, metronidazole concentrations in the pockets were generally above MIC50 for susceptible periopathogens 24 h after 1 application of a 25% metronidazole gel.

Systemic absorption of metronidazole after application of a metronidazole 25% dental gel

Systemic absorption of metronidazole was studied after one application of a metronidazole 25% dental gel into inflamed periodontal pockets. 14 patients with periodontal disease participated. Metronidazole gel was applied into the pockets of all teeth with probing depth > or = 5 mm, minimum 10 teeth/patient. Excess gel was carefully collected in order to calculate the amount of metronidazole applied into the pockets. Blood samples for analysis of metronidazole in plasma were taken before and up to 72 h after application. To determine the bioavailability of metronidazole administered as gel, the patients were later given an i.v. dose of 100 mg metronidazole. Metronidazole was quantified by HPLC. The mean actual dose of metronidazole in gel was 55 mg (SD: 24 mg, range: 29-103 mg). Allowing for the fact that excess gel corresponding to about 60% of the applied amount of metronidazole under normal clinical conditions may be swallowed, the systemic load after one application of metronidazole 25% dental gel will still be less than after one metronidazole 250 mg tablet. Peak plasma concentrations varied between 223 and 1303 ng/ml (mean: 581 ng/mk, SD: 320 ng/ml) and were reached within 2 to 8 h (mean: 4.4 h). The mean bioavailability of metronidazole dental gel was 71%.

3 regimens of topical metronidazole compared with subgingival scaling on periodontal pathology in adults

This report presents the findings from an open randomized multicentre clinical trial designed to compare the clinical efficacy of scaling with application of 3 different preparations/dose frequencies of topical metronidazole in the treatment of adult periodontitis. The 4 treatments were: (A) metronidazole 25% dental gel administered 1 x a week for 2 weeks; (B) metronidazole 15% dental gel applied 1 x a week for 2 weeks; (C) metronidazole 15% dental gel applied 2 x a week for 2 weeks; (D) subgingival scaling, performed 1 x only. A split mouth design was used. Patients were included in the study if they had at least 1 tooth in each quadrant with a pocket depth > or = 5 mm in at least 1 of 4 sites. A total of 61 patients from 4 centres were entered into the study. The efficacy parameters were probing pocket depth and bleeding on probing. Follow-up visits for recording of clinical efficacy were made at 2, 4, 6 and 12 weeks after the end of metronidazole treatment. All 3 antibiotic treatments (A, B, C) reduced the symptoms of periodontal pathology and yielded results comparable to those seen after subgingival scaling (D). When using a topical drug therapy, it seems important to use a preparation that requires as few applications as possible. The best candidate for drug therapy would therefore be treatment (A) metronidazole 25% applied 1 x a week for 2 weeks.

In vitro studies of elastin-fibrin biomaterial degradation: preservative effects of protease inhibitors and antibiotics

The degradability of a new elastin-fibrin material was tested in vitro versus human pancreatic elastase (HPE) and plasmin (PL) activities. It is shown that aprotinine Iniprol, a well-known protease inhibitor and Eglin C, a new potent inhibitor of HPE, especially when used in synergy, efficiently protected the material. A small amount of specific antibiotics was incorporated into the material. The two products will allow the material to be used in digestive surgery with improved safety.

Topical application of doxycycline on periodontally involved root surfaces in vitro: comparative analysis of substantivity on cementum and dentin

In this study, substantivity of topically applied doxycycline hydrochloride on root surfaces obtained from patients with periodontal disease was studied in vitro. Cementum and dentin specimens were impregnated with aqueous solutions of doxycycline for 3 minutes, and incubated in serum for 10 minutes, 7 days, and 14 days. Substantivity was determined by agar diffusion inhibition assay. Comparative analyses of cementum versus dentin groups were conducted with 2-way analysis of variance. Results indicated that there was no statistically significant differences between the binding potential of doxycycline to cementum and dentin specimens. Antibacterial effect of specimens treated with the concentration of 100 mg/ml persisted for 14 days, indicating the presence of doxycycline in biologically active form. Our findings demonstrate the long lasting substantivity of doxycycline hydrochloride on periodontally diseased root surfaces and supports the concept of using root surfaces as a substrate for the deposition and slow release for local tetracycline delivery.

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.

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

The growth in the dental literature continues to escalate, as evidenced by the publication of at least 326 new books in 1988 and 1989 and more than 20 new journals in 1989. There still appears to be undue emphasis on quantity instead of quality of research. This proliferation in the literature poses ever increasing difficulties to this Committee in filtering out the articles that are of particular interest to the members of the Academy and identifying those that are most likely to have a major impact on dental practice and service. The subjects covered include periodontics, caries and preventive dentistry, craniomandibular disorders, occlusion, pulp biology, ceramics, and restorative dental materials.