Concentration of doxycycline in human gingival fluid

Antibacterial Effects of Modified Implant Abutment Surfaces for the Prevention of Peri-Implantitis-A Systematic Review

The aim of the present study was to systematically review studies investigating antibacterial implant abutment surfaces or coatings, which may suppress bacterial growth to prevent plaque-induced peri-implant inflammatory disease. Data were collected after identification of case, assay/laboratory procedure, predicate/reference standard and outcome (CAPO). Seven hundred and twenty (720) records were identified through data base searching. After screening nine publications fulfilled inclusion criteria and were included. The following surfaces/coatings showed antibacterial properties: Electrochemical surface modification of titanium by the anodic spark deposition technique; doxycycline coating by cathodic polarization; silver coating by DC plasma sputter; titanium nitride; zirconium nitride and microwave assistant nano silver coating. Since the current state of the literature is rather descriptive, a meta-analysis was not performed. While several abutment coatings showed to have antibacterial capacity, some of them also influenced the behavior of investigated human cells. None of the studies investigated the long-term effect of surface modifications. Since surface changes are the main contributing factor in the development of antibacterial effects, the biodegradation behavior must be characterized to understand its durability. To date there is no effective structure, material or strategy to avoid peri-implant inflammation used as clinical routine. Furthermore, clinical studies are scarce.

Antimicrobial effect of nanostructured membranes for guided tissue regeneration: an in vitro study

OBJECTIVE

The purpose of this in vitro study was to evaluate the antibacterial effect of a novel non-resorbable, bioactive polymeric nanostructured membrane (NMs), when doped with zinc, calcium and doxycycline.

METHODS

A validated in vitro subgingival biofilm model with six bacterial species (Streptococcus oralis, Actinomyces naeslundii, Veillonela parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) was used. The experimental NMs, with and without being doped with doxycycline, calcium and zinc, were placed on hydroxyapatite (HA) discs. As positive control membranes, commercially available dense polytetrafluoroethylene (d-PTFE) membranes were used and, as negative controls, the HA discs without any membrane. The experimental, positive and negative control discs were exposed to a mixed bacterial suspension, at 37 °C under anaerobic conditions, during 12, 24, 48 and 72 h. The resulting biofilms were analyzed through scanning electron microscopy (SEM), to study their structure, and by quantitative polymerase chain reaction (qPCR), to assess the bacterial load, expressed as colony forming units (CFU) per mL. Differences between experimental and control groups were evaluated with the general linear model and the Bonferroni adjustment.

RESULTS

As shown by SEM, all membrane groups, except the NMs with doxycycline, resulted in structured biofilms from 12-72 hours. Similarly, only the membranes loaded with doxycycline demonstrated a significant reduction in bacterial load during biofilm development, when compared with the control groups (p < 0.001).

SIGNIFICANCE

Doxycycline-doped nanostructured membranes have an impact on biofilm growth dynamics by significant reducing the bacterial load.

Antimicrobial Activity of an Amnion-Chorion Membrane to Oral Microbes

Objective

The aim of this study was to evaluate wound biomodification by assessing antimicrobial properties present within a human-derived composite amnion-chorion membrane (ACM).

Methods

Membranes analyzed were the human-derived ACM BioXclude™ and the porcine-derived collagen membrane Bio-Gide®. Paper discs with and without tetracycline served as positive and negative controls, respectively. The same number of colony-forming units per milliliter for each bacterial species (Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Streptococcus oralis) was inoculated on each of the discs. Discs from each group were removed at 12 and 24 hours and sonicated to remove the bacteria off the membranes. A serial dilution was performed to quantify bacterial growth.

Results

The ACM inhibited growth at all time points, with all bacterial strains, identical to the negative control tetracycline discs. The collagen membrane and positive controls did not inhibit growth of any of the bacterial species throughout the 24-hour study period. P < 0.05 for microbial growth on ACM or negative control vs. either collagen membrane or positive control.

Conclusion

ACM was proven to be as bactericidal as paper discs inoculated with tetracycline at its minimum bactericidal concentration. The ACM bactericidal property may be beneficial in the early wound healing process.

A Versatile Biocompatible Antibiotic Delivery System Based on Self-Assembling Peptides with Antimicrobial and Regenerative Potential

Periodontitis is a chronic inflammatory and tissue-destructive disease. Since the polymicrobiome in the oral cavity makes it difficult to treat, novel therapeutic strategies are required. Hydrogels based on self-assembling peptides (SAP) can be suitable candidates for periodontal therapy due to their injectability, biocompatibility, cargo-loading capacity, and tunable physicochemical and mechanical properties. In this study, two SAP hydrogels (P11-4 and P11-28/29) are examined for their intrinsic antimicrobial activity, regenerative potential, and antibiotic delivery capacity. A significant antibacterial effect of P11-28/29 hydrogels on the periodontal pathogen Porphyromonas gingivalis and a less pronounced effect for P11-4 hydrogels is demonstrated. The metabolic activity rates of human dental follicle stem cells (DFSCs), which reflect cell viability and may thus indicate the regenerative capacity, are similar on tissue culture polystyrene (TCPS) and on P11-4 hydrogels after 14 days of culture. Noticeably, both SAP hydrogels strengthen the osteogenic differentiation of DFSCs compared with TCPS. The incorporation of tetracycline, ciprofloxacin, and doxycycline does not affect fibril formation of either SAP hydrogel and results in favorable release kinetics up to 120 h. In summary, this study reveals that P11-SAP hydrogels combine many favorable properties required to make them applicable as prospective novel treatment strategy for periodontal therapy.

Doxycycline Release of Dental Implants With Nanotube Surface, Coated With Poly Lactic-Co-Glycolic Acid for Extended pH-controlled Drug Delivery

When dental implants become infected, the progression of the disease is rapid. Commercially available dental implant surfaces can be easily contaminated, resulting in rapid progression of peri-mucositis and peri-implantitis. The aim of this study was to evaluate, in vitro, the pattern of doxycycline release from by dental implants with titanium nanotube surface (DINS) at different pHs to examine novel drug loading and chemical coating techniques. Nine DINS were loaded with doxycycline and subsequently coated with polylactic-co-glycolic acid (PLGA). High-performance liquid chromatography (HPLC) was used to measure the amounts of released doxycycline in a 30-day period. Cytotoxicity of the DINS was evaluated by an assay using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT). The results showed that the experimental DINS coated with doxycycline and PLGA showed a mean drug release during the experimental period for the groups: pH 7.4 (8.39 μg/mL), pH 6.4 (8.63 μg/mL). The pH 5.4 (15.18 μl/mL) doxycycline release from DINS was faster at pH 5.4 than those at pHs 6.4 and 7.4 (P = .0031 and .0034, respectively). This new surface treatment of dental implants with titanium nanotubes and subsequent drug loading demonstrated biocompatibility and sustained doxycycline release over a 30-day period. Additional studies are needed in order to adopt a stable drug release at neutral pH environment while warranting a constant drug release in an acidic pH environment.

Antibacterial effects of polymeric PolymP-n Active nanoparticles. An in vitro biofilm study

OBJECTIVE

to study the antibacterial effect of polymeric PolymP-n Active nanoparticles using an in vitro subgingival biofilm model.

METHODS

Hydroxyapatite discs coated with five modalities of nanoparticles (NPs): NPs, NPs doped with zinc, calcium, silver and doxycycline, PBS as control, and Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were studied in a static in vitro biofilm model (12, 24, 48, and 72h). Nano-roughness of the different disc surfaces (SRa, in nm) and morphological characteristic of the biofilms (thickness (μm) and bacterial viability) were studied by different microscopy modalities. Quantitative Polymerase Chain Reaction was used to assess the effect of the nanoparticles on the bacterial load (colony forming unit per milliliter) (CFUmL^-1). Analysis of variance and post-hoc testing with T3 Dunnett́s, and Student Newman Keuls correction was used. Results were considered statistically significant at p<0.05.

RESULTS

Surfaces containing the different nanoparticles showed significant increments in roughness when compared to controls (p<0.05). A similar biofilm formation and dynamics was observed, although reductions in bacterial viability were detected in biofilms in contact with the different nanoparticles, more pronounced with silver and doxycycline NPs. Doxycycline-NPs biofilms resulted in unstructured biofilm formation and significantly lower number of the six species when compared with the other nanoparticles specimens and controls (p<0.001 in all cases).

SIGNIFICANCE

Polymeric PolymP-n Active nanoparticles when combined with silver and doxycycline showed a significant antibacterial effect when tested in an in vitro subgingival biofilm model.

Role of clove oil in solvent exchange-induced doxycycline hyclate-loaded Eudragit RS in situ forming gel

•

Role of clove oil (CO) in doxycycline hyclate (DH)-loaded Eudragit RS (ERS) in situ forming gel (ISG) was investigated.

•

CO could solubilize ERS and increase the viscosity of ISG and also minimize DH burst release with sustainable DH release.

•

ISGs comprising CO could expel through the 27-gauge needle and transform into matrix depot in simulated crevicular fluid.

•

Antimicrobial activities against all test bacterias were increased when increasing CO and N-methyl pyrrolidone (NMP) ratio.

•

DH-loaded ERS ISG comprising CO could be used as a local drug delivery system for periodontitis treatment.

Solvent exchange induced in situ forming gel (ISG) is the promising drug delivery system for periodontitis treatment owing to the prospect of maintaining an effective high drug level in the gingival crevicular fluid. In the present study, the influence of clove oil (CO) on the characteristics of doxycycline hyclate (DH)-loaded ISG comprising Eudragit RS (ERS) was investigated including viscosity/rheology, syringeability, in vitro gel formation/drug release, matrix formation/solvent diffusion and antimicrobial activities. CO could dissolve ERS and increase the viscosity of ISG and its hydrophobicity could also retard the diffusion of solvent and hinder the drug diffusion; thus, the minimization of burst effect and sustained drug release were achieved effectively. All the prepared ISGs comprising CO could expel through the 27-gauge needle for administration by injection and transform into matrix depot after exposure to the simulated gingival crevicular fluid. The antimicrobial activities against Staphylococcus aureus, Escherichia coli, Streptococcus mutans and Porphyromonas gingivalis were increased when the ratio of CO and N-methyl pyrrolidone (NMP) was decreased from 1:1 to 1:10 owing to higher diffusion of DH except that for C. albicans was increased as CO amount was higher. Therefore, CO could minimize the burst while prolonging the drug release of DH-loaded ERS ISG for use as a local drug delivery system for periodontitis treatment.

[Implants for drug substance delivery]

Implants for controlled drug delivery can be very helpful to improve the therapeutic efficacy of a medical treatment, and at the same time reduce the risk of toxic side effects. In this article, four different strategies are exemplarily presented: hybrid bone substitutes combining hydroxyapatite and chitosan hydrogels; vascular stents coated with a bio-inspired polymer; cochlear implants for local dexamethasone delivery; and in-situ forming implants for periodontitis treatment. But this is only a restricted selection, and numerous other approaches and applications based on implants releasing a drug (or a combination of drugs) exist. Compared to conventional implants or pharmaceutical dosage forms, they might offer decisive advantages.

Mechanistic analysis of PLGA/HPMC-based in-situ forming implants for periodontitis treatment

In-situ forming implant formulations based on poly(lactic-co-glycolic acid) (PLGA), acetyltributyl citrate (ATBC), minocycline HCl, N-methyl pyrrolidone (NMP) and optionally hydroxypropyl methylcellulose (HPMC) were prepared and thoroughly characterized in vitro. This includes electron paramagnetic resonance (EPR), nuclear magnetic resonance ((1)H NMR), mass change and drug release measurements under different conditions, optical microscopy, size exclusion chromatography (SEC) as well as antibacterial activity tests using gingival crevicular fluid samples from periodontal pockets of periodontitis patients. Based on these results, deeper insight into the physico-chemical phenomena involved in implant formation and the control of drug release could be gained. For instance, the effects of adding HPMC to the formulations, resulting in improved implant adherence and reduced swelling, could be explained. Importantly, the in-situ formed implants effectively hindered the growth of bacteria present in the patients' periodontal pockets. Interestingly, the systems were more effectively hindering the growth of pathogenic bacterial strains (e.g., Fusobacterium nucleatum) than that of strains with a lower pathogenic potential (e.g., Streptococcus salivarius). In vivo, such a preferential action against the pathogenic bacteria can be expected to give a chance to the healthy flora to re-colonize the periodontal pockets.

In-situ forming composite implants for periodontitis treatment: How the formulation determines system performance

Periodontitis is the primary cause of tooth loss in adults and a very wide-spread disease. Recently, composite implants, based on a drug release rate controlling polymer and an adhesive polymer, have been proposed for an efficient local drug treatment. However, the processes involved in implant formation and the control of drug release in these composite systems are complex and the relationships between the systems' composition and the implants' performance are yet unclear. In this study, advanced characterization techniques (e.g., electron paramagnetic resonance, EPR) were applied to better understand the in-situ forming implants based on: (i) different types of poly(lactic-co-glycolic acid) (PLGA) as drug release rate controlling polymers; (ii) hydroxypropyl methylcellulose (HPMC) as adhesive polymer; and (iii) doxycycline or metronidazole as drugs. Interestingly, HPMC addition to shorter chain PLGA slightly slows down drug release, whereas in the case of longer chain PLGA the release rate substantially increases. This opposite impact on drug release was rather surprising, since the only difference in the formulations was the polymer molecular weight of the PLGA. Based on the physico-chemical analyses, the underlying mechanisms could be explained as follows: since longer chain PLGA is more hydrophobic than shorter chain PLGA, the addition of HPMC leads to a much more pronounced facilitation of water penetration into the system (as evidenced by EPR). This and the higher polymer lipophilicity result in more rapid PLGA precipitation and a more porous inner implant structure. Consequently, drug release is accelerated. In contrast, water penetration into formulations based on shorter chain PLGA is rather similar in the presence and absence of HPMC and the resulting implants are much less porous than those based on longer chain PLGA.

Antibiotic susceptibility of Aggregatibacter actinomycetemcomitans JP2 in a biofilm

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Evaluation of the effect of allograft with doxycycline versus the allograft alone in the treatment of infrabony defects: A controlled clinical and radiographical study

BACKGROUND

Successful prevention and treatment of periodontal disease are contingent on effective control of periodontopathic microbiota based on the premise of periodontal disease being infectious disorders. An anti-microbial agent, i.e., doxycycline has been incorporated into the allograft to control infection and facilitate healing during and after periodontal therapy.

MATERIALS AND METHODS

Using a split-mouth design, 15 patients showing clinical evidence of almost identical bilateral infrabony defects requiring bone grafting procedures were randomly selected. In each patient, infrabony defects on one side were designated as Group A (control group) and infrabony defects of the contralateral side of the same arch were designated as Group B (test group). Clinical assessment of probing pocket depth and attachment level and radiographic evaluation of the defect depth was done pre-operatively and at 12-week and 24-week post-operatively. The relative efficacy of the two treatment modalities was evaluated using paired Student's t-test and the comparative evaluation between the two groups over the 3 time intervals was done using independent Student's t-test.

RESULTS

Both the groups exhibited a highly significant reduction in probing depth and gain in clinical attachment level (CAL) and a linear bone fill at the end of 12 and 24 weeks. Comparative evaluation showed a statistically significant gain in bone fill in Group B as compared to Group A, whereas a non-significant reduction in probing depth and gain in CALs between the two groups at the end of 24 weeks (whereas mean reduction in probing depth and gain in CAL were also greater in Group B but the difference was statistically non-significant).

CONCLUSION

The increase in linear bone fill in Group B signifies the role of doxycycline in augmenting regenerative potential of allograft by combating residual infection and through host modulation.

Minocycline hydrochloride nanoliposomes inhibit the production of TNF-α in LPS-stimulated macrophages

Background

As an adjunctive treatment of chronic periodontitis, it seems that the application of periocline or the other antimicrobials is effective against periodontopathogens. In this study, nanoliposomes were investigated as carriers of minocycline hydrochloride and the inhibition effects of minocycline hydrochloride nanoliposomes on the proliferation and lipopolysaccharide (LPS)-stimulated production of tumor necrosis factor-α (TNF-α) of macrophages were elucidated.

Methods

After stimulation with 10 μg/mL LPS, murine macrophages (ANA-1) were treated with 10, 20, 40, 50 and 70 μg/mL 2% minocycline hydrochloride nanoliposomes, minocycline hydrochloride solution, and periocline for 6, 12, 24, 48 and 60 hours, respectively. A tetrazolium (MTT) assay was used to evaluate macrophages cell proliferation rate and the levels of TNF-α mRNA were measured by SYBR Green Real Time PCR.

Results

Ten to 70 μg/mL 2% minocycline hydrochloride nanoliposomes, minocycline hydrochloride solution, and periocline showed dose- and time-dependent inhibition of ANA-1 proliferation. Minocycline hydrochloride nanoliposomes showed dose- and ratio-dependent inhibition of LPS-stimulated TNF-α secretion of ANA-1. The inhibition effect of 10 μg/mL minocycline hydrochloride nanoliposomes was significantly better than that of two positive control groups, and equated to that of 60 or 70 μg/mL periocline. The expression of TNF-α mRNA in experimental group continued to reduce linearly with time.

Conclusion

All three preparations of minocycline hydrochloride showed dose- and time-dependent inhibition of proliferation of ANA-1. Minocycline hydrochloride nanoliposomes have stronger and longer inhibition effect on LPS-stimulated TNF-α secretion of macrophages cell than minocycline hydrochloride solution and periocline.

Oral doxycycline for the treatment of chronic leg ulceration

This pilot study investigated oral doxycycline as an adjunct to compression therapy for non-healing venous leg ulcers. Ten patients received doxycycline 20 mg twice daily (low-dose doxycycline) and ten patients received doxycycline 100 mg twice daily (high-dose doxycycline). Utilising a pre-test post-test study design, ulcer area was measured and wound fluid was collected before and after 4 weeks of treatment. In the high-dose doxycycline group, the reduction in median ulcer area was 48% (p = 0.1) and there was a significant reduction in wound fluid total matrix metalloprotease-1 (p = 0.02). These effects were not observed with low-dose doxycycline. There were no significant changes in wound fluid tumour necrosis factor-α or quantitative bacteriology following treatment with low-dose or high-dose doxycycline. There was no significant relationship between change in ulcer area and matrix metalloprotease-1, -8 or -9 activities in wound fluid at the end of treatment. Median wound fluid doxycycline concentrations after 4 weeks of treatment were 0.2 mg/L(0.45 lM) and 2.3 mg/L (5.18 lM) [DOSAGE ERROR CORRECTED] in the low-dose and high-dose groups, respectively, which are lower than that previously shown to inhibit matrix metalloproteases and tumour necrosis factor-α. Our study suggests that doxycycline 100 mg twice daily may improve the healing rate of recalcitrant leg ulcers, however the mechanism remains unclear.

Azithromycin concentrations in blood and gingival crevicular fluid after systemic administration

BACKGROUND

Azithromycin is a macrolide antibiotic that is active against several periodontal pathogens. Macrolides are taken up and concentrated inside gingival fibroblasts, which could influence their pharmacokinetics. This study tests the hypothesis that steady-state levels of azithromycin are higher and more sustained in gingival crevicular fluid (GCF) than in serum.

METHODS

Four healthy patients received an initial dose of 500-mg azithromycin followed by 250-mg doses on each of the next 2 days. Serum and GCF samples were obtained 2 hours after the last dose on day 2, and on days 4 and 7. GCF samples were collected from maxillary posterior sites with paper strips. The strips were pooled and eluted with high-purity water. After extraction, the azithromycin content of the serum samples and GCF eluates was determined with an agar diffusion bioassay.

RESULTS

On days 2, 4, and 7, the concentrations of azithromycin in blood serum were 0.22 ± 0.02, 0.08 ± 0.02, and 0.04 ± 0.01 μg/mL, respectively. The concentrations in GCF were 8.82 ± 1.25, 7.90 ± 1.72, and 7.38 ± 1.15 μg/mL, respectively. Mean GCF levels were significantly higher than mean serum levels (P ≤0.02; paired t test).

CONCLUSIONS

The findings demonstrate that the pharmacokinetic profiles of azithromycin are different in GCF and serum. At steady state, azithromycin concentrations in GCF were higher and more sustained than those in serum. Based on previous studies, the levels observed in GCF were above the minimal inhibitory concentration for Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Prevotella intermedia.

Systemic detection of doxycycline after local administration

OBJECTIVES

Controlled release delivery (CRD) systems are used to extend the half-life of topical antibiotics in gingival crevicular fluid (GCF), while avoiding systemic contamination with antibiotics. When multiple periodontitis sites are treated by subgingival application of a one-component copolymer gel containing 14% doxycycline, it is likely that low levels of the antibiotic can be detected in blood by high performance liquid chromatography (HPLC).

METHODS

Twelve patients with severe periodontitis and one single defect per patient were treated with one single subgingival application of a new one-component doxycycline gel (14%) in each defect (the UNISITE group). Furthermore, 12 patients with between 3 and 9 periodontal defects were treated with a single application of the same doxycycline gel in each defect, resulting in 3-9 applications per patient (the MULTISITE group). Doxycycline was separated and quantitatively measured with HPLC using a UV detector.

RESULTS

In saliva, the maximum doxycycline concentration of the MULTISITE patients was nearly 10-fold higher than in the UNISITE group. In GCF specimens, maximum doxycycline concentrations were the same magnitude in both the MULTISITE and UNISITE groups. Only one UNISITE patient showed detectable levels of doxycycline in blood serum (maximum application: 0.18 µg/ml). Six MULTISITE patients exhibited measurable concentrations of doxycycline in their serum samples (maximum values: 0.12-0.76 µg/ml). The mean systemic concentration following application of the doxycycline-containing gel to multiple sites was as high as 160 ng/ml within minutes following application. Within approximately 1 h, this fell to levels below the limit of detection by HPLC (<50 ng/ml).

CONCLUSIONS

Systemic contamination with doxycycline after topical administration may occur even after unisite application if no periodontal dressing is used. Locally administered doxycycline can be identified in the systemic circulation at levels far below those expected to have antibacterial effects. Systemic concentration following application to a single site was always below levels capable of detection by HPLC.

Recognizing doxycycline-induced esophageal ulcers in dental practice: a case report and review

BACKGROUND

Doxycycline-induced esophageal ulcer is a documented adverse drug reaction. Unfortunately, many health care professionals are not familiar with this particular drug reaction. Because doxycycline frequently is prescribed in the clinical practice of periodontics, it is important for dentists to be aware of this potential drug reaction.

METHODS

The authors describe the case of a patient who was taking doxycycline after undergoing periodontal surgery and experienced a complication. The diagnosis revealed that the patient had developed an esophageal ulcer as a result of taking the doxycycline.

RESULTS

The patient's esophageal ulcer resolved with the aid of dietary changes and a prescription of rabeprazole, a proton pump inhibitor.

CONCLUSIONS

and

CLINICAL IMPLICATIONS

The etiology of doxycycline-induced esophageal ulceration is complex, and proper diagnosis is essential for its resolution. Dentists should be aware of the potential for this adverse drug reaction.

Antibiotic resistance in an in vitro subgingival biofilm model

INTRODUCTION

The purpose of this study was to utilize an in vitro biofilm model of subgingival plaque to investigate resistances in subgingival biofilm communities to antibiotics commonly used as adjuncts to periodontal therapy.

METHODS

Biofilms were grown on saliva-coated hydroxyapatite supports in trypticase-soy broth for 4 h-10 days and then exposed for 48 h to either increasing twofold concentrations of tetracycline, amoxicillin, clindamycin, and erythromycin or therapeutically achievable concentrations of tetracycline, doxycycline, minocycline, amoxicillin, metronidazole, amoxicillin/clavulanate, and amoxicillin/metronidazole.

RESULTS

Concentrations necessary to inhibit bacterial strains in steady-state biofilms were up to 250 times greater than the concentrations needed to inhibit the same strains grown planktonically. In the presence of therapeutically available antibiotic concentrations, significantly higher proportions of the biofilms remained viable as the biofilms reached steady-state growth. The combinations of amoxicillin/clavulanate and amoxicillin/metronidazole were the most effective in suppressing growth. These combinations were particularly effective against biofilms up to and including 7 days of age and inhibited 90% or more of the bacteria present relative to untreated controls. As the biofilms approached steady state, these combinations were less effective with 50-60% of the bacteria retaining viability.

CONCLUSION

Most, but not all, species of subgingival bacteria are considerably more resistant in biofilms than in planktonic cultures. Resistance appeared to be age-related because biofilms demonstrated progressive antibiotic resistance as they matured with maximum resistance coinciding with the steady-state phase of biofilm growth.

Timing Affects the Clinical Outcome of Adjunctive Systemic Antibiotic Therapy for Generalized Aggressive Periodontitis

BACKGROUND

Systemic antibiotics improve the outcome of scaling and root planing (SRP) in patients exhibiting severe periodontitis. This study evaluated the influence of timing of adjunctive systemic antibiotics in the sequence of periodontal therapy.

METHODS

Two cohorts of patients with generalized aggressive periodontitis and treated by SRP, adjunctive antibiotics, and supportive periodontal therapy (SPT) were analyzed retrospectively. Cohort A (17 patients; 36 +/- 5 years of age) received systemic amoxicillin/metronidazole immediately after SRP ("immediate"); cohort B (17 patients; 36 +/- 4 years of age) received the same regimen 3 months after SRP, following SPT, including subgingival reinstrumentation ("late"). Clinical parameters, including probing depth (PD), relative attachment level (RAL), bleeding on probing (BOP), and suppuration, were recorded with a pressure-sensitive electronic probe at baseline and 3 and 6 months after SRP.

RESULTS

Significant time*group interactions were found for all clinical parameters except BOP, i.e., timing of antibiotic therapy affected the course of clinical changes over time. Immediate antibiotic therapy produced significantly higher initial changes (0 to 3 months) in PD and RAL. Late antibiotic therapy at 3 months resulted in additional significant improvements in all clinical parameters between 3 and 6 months. In initially deep sites (baseline PD >6 mm), improvements in PD and RAL over 6 months were significantly higher with immediate antibiotic therapy compared to late antibiotic therapy.

CONCLUSION

Within the limits of a retrospective analysis, these findings indicate that administration of amoxicillin/metronidazole immediately after initial SRP provides more PD reduction and RAL "gain" in initially deep sites than late administration at SPT with reinstrumentation after 3 months.

Chemically modified tetracyclines stimulate matrix metalloproteinase-2 production by periodontal ligament cells

BACKGROUND AND OBJECTIVE

The purpose of this study was to investigate the effects of chemically modified tetracyclines (CMTs) on the production of gelatinases [matrix metalloproteinase (MMP)-2 and -9] by human periodontal ligament (PDL) cells, and on the activity of recombinant gelatinases.

MATERIAL AND METHODS

Human PDL cells were cultured with CMT-1, -3, -5, -7 or -8 in concentrations of 0, 1, 5, 10, 20, 50, 100, 200 and 500 microm. Gelatin zymography was used to determine MMP-2 and -9 production of the cells. The amount of DNA present in the cultures was analyzed using a fluorescent assay. The cytotoxicity of the CMTs was also determined. Recombinant human MMP-2 and -9 were incubated with the CMTs (0-500 microm) and their activity was analyzed using an internally quenched fluorogenic substrate.

RESULTS

MMP-2 production was stimulated up to sevenfold by CMT-1, -3, -7 and -8 at low concentrations (10-200 microm). No significant amounts of MMP-9 were produced. In contrast, MMP-2 and -9 activity was reduced by approximately 10-40-fold at higher concentrations (200-500 microm). CMT-5 had no effect on the production or on the activity of MMP-2 and -9. Only CMT-3 and -8 had cytotoxic effects on the PDL cells at the highest concentrations.

CONCLUSION

Surprisingly, CMTs are able to stimulate MMP-2 production at relatively low concentrations. However, at higher concentrations they exert a much stronger inhibitory effect on gelatinase activity. A possible stimulatory effect of CMTs on MMP production should be considered in their clinical use.

Modulation of gingival fibroblast minocycline accumulation by biological mediators

Gingival fibroblasts actively accumulate tetracyclines, thereby enhancing their redistribution from blood to gingiva. Since growth factors and pro-inflammatory cytokines regulate many fibroblast activities, they could potentially enhance fibroblast minocycline accumulation. To test this hypothesis, we treated gingival fibroblast monolayers for 1 or 6 hours with platelet-derived growth factor-BB (PDGF), fibroblast growth factor-2 (FGF), transforming growth factor-beta1 (TGF), or tumor necrosis factor-alpha (TNF). Minocycline uptake was assayed at 37 degrees by a fluorescence method. All 4 factors significantly enhanced minocycline uptake (P < or = 0.008, ANOVA), primarily by increasing the affinity of transport. Treatment for 6 hours with 10 ng/mL FGF, PDGF, TGF, or TNF enhanced fibroblast minocycline uptake by 19% to 25%. Phorbol myristate acetate enhanced fibroblast minocycline uptake by 28%, suggesting that protein kinase C plays a role in up-regulating transport. These effects on transport provide a mechanism by which systemic tetracyclines could be preferentially distributed to gingival wound or inflammatory sites.

Long-term treatment with sub-antimicrobial dose doxycycline has no antibacterial effect on intestinal flora

AIM

The purpose of this study was to determine if a 9-month regimen of sub-antimicrobial doxycycline (20 mg, bid) had an effect on either the intestinal or the vaginal microflora.

MATERIAL AND METHODS

A total of 69 periodontally diseased subjects were randomized to receive drug or placebo control for a 9-month period. Stool specimens and vaginal swabs were collected at baseline and after 3 and 9 months of therapy. Samples were examined for total anaerobic counts, opportunistic pathogens, and doxycycline-resistant (>or=4 microg/ml) bacteria. All isolates that survived sub-culture were identified and their susceptibilities determined to six antibiotics. Analyses were performed to determine if treatment differences were present.

RESULTS

The only statistically significant differences (p<0.05) between the two treatment groups occurred in the doxycycline-resistant counts at the baseline sample period for the faecal samples. This imbalance was before treatment initiation and the administration of the study drug. No between-treatment differences were detected at either the 3- or 9-month sample period either in the predominant bacterial taxa present or in their antibiotic susceptibilities.

CONCLUSIONS

There was no evidence that sub-antimicrobial doxycycline treatment exerted an effect on the composition or doxycycline resistance level of either the faecal or the vaginal microflora.

The gingival crevicular fluid ciprofloxacin level in subjects with gingivitis and periodontitis, and its effects on clinical parameters

OBJECTIVES

The purpose of this study, conducted on patients with gingivitis and periodontitis, was twofold: to find out the serum and gingival crevicular fluid concentration of ciprofloxacin, which is a common drug used effectively against Actinobacillus actinomycetemcomitans and to determine the effects of ciprofloxacin administration on clinical parameters.

METHOD

A total of 32 adult patients, consisting of 16 subjects with gingivitis and 16 subjects with untreated chronic periodontitis, were included in the study. The subjects were divided into four groups: group I included eight subjects with chronic gingivitis who had not previously received any ciprofloxacin; group II included eight subjects with chronic gingivitis to whom three doses of ciprofloxacin were administered (Siprosan 500 mg) to establish adequate gingival crevicular fluid and serum concentrations of the agent; group III consisted of eight subjects with chronic periodontitis who had not received any ciprofloxacin; group IV included eight subjects with chronic periodontitis to whom three doses of ciprofloxacin were administered to establish adequate gingival crevicular fluid and serum concentrations of the agent. All patients were systemically healthy, free of pain and reported no current medication usage. Each patient was treated with scaling and/or root planing using specific hand instruments under local anesthesia. Gingival index, plaque index and clinical attachment levels of the teeth were used to determine the clinical condition of the subjects and findings were recorded at the beginning, seventh day, 21st day and third month of the study. Serum ciprofloxacin level was measured in venous blood. Approximately 5 ml of venous blood was drawn from subjects in groups II and IV using a standard venipuncture technique. Gingival crevicular fluid samples were sampled from six interproximal sites with six paper strips in the posterior region of upper jaw (excluding third molar) and all gingival crevicular fluid and serum samples were evaluated by high-performance liquid chromatography.

RESULTS

The serum concentrations of ciprofloxacin at the first and 72nd hour were not significantly different in subjects with periodontitis compared to subjects with gingivitis. But the gingival crevicular fluid concentrations of ciprofloxacin at the same hours were significantly high in subjects with periodontitis compared to subjects with gingivitis. Both subjects with gingivitis and periodontitis had significantly higher ciprofloxacin levels in the gingival crevicular fluid than in serum. The application of ciprofloxacin did not have any positive or statistically significant effect upon the clinical parameters of the subjects with gingivitis. On the other hand, a significant decrease in the clinical attachment level scores of the subjects with periodontitis (group IV) was observed compared to group III in the 21st day and third month.

CONCLUSION

According to these results, the use of ciprofloxacin as an alternative drug in subjects with periodontitis but not gingivitis can be recommended. However, long-term studies are also needed to assess the effects of ciprofloxacin on clinical parameters.

Nonsurgical approaches for the treatment of periodontal diseases

This article reviews nonsurgical approaches for the management of periodontal diseases. A brief review of the pathogenesis of periodontitis allows the reader to identify the potential points of intervention. Assessment of risk factors for periodontitis and the potential for risk reduction are introduced as the first part of a three-pronged approach to therapy. Antimicrobial approaches, including the use of mechanical therapy, antiseptics, and antibiotics,are described next. Host modulatory therapy is addressed as the fi-nal component of the nonsurgical approach to periodontal therapy. Clinical applications of these nonsurgical options are presented as part of the treatment strategy.

Distribution of systemic ciprofloxacin and doxycycline to gingiva and gingival crevicular fluid

BACKGROUND

Systemic fluoroquinolones and tetracyclines reach steady-state levels in gingival crevicular fluid (GCF) that are several-fold higher than their levels in serum. The mechanism by which this occurs is unclear, but gingival fibroblasts are known to accumulate these agents. Uptake by fibroblasts could enhance their distribution to gingiva. To test this hypothesis, steady-state levels of these agents were assayed in serum, gingival connective tissue (GCT), and GCF.

METHODS

Healthy subjects who needed resective periodontal surgery participated in the study. Approximately 78 hours prior to the surgical appointment, each subject began a 3-day regimen of ciprofloxacin or doxycycline. At the surgical appointment (scheduled approximately 6 hours after the last dose), samples of blood and GCT were collected. GCF samples were collected on paper strips and measured with an electronic device. Samples were extracted and analyzed by high performance liquid chromatography.

RESULTS

Mean ciprofloxacin levels in serum, GCT, and GCF were 0.40 microg/ml, 1.38 microg/g, and 1.66 microg/ml, respectively (P<0.001, N=9). For doxycycline, these levels were 1.11 microg/ml, 2.03 microg/g, and 2.41 microg/ml, respectively (P=0.002, N=8). For both agents, the GCT and GCF levels were significantly higher than serum levels (P<0.05), but not significantly different from each other.

CONCLUSIONS

Our findings suggest that fibroblasts could play an important role in the distribution of fluoroquinolones and tetracyclines to the gingiva. By accumulating these agents in GCT, fibroblasts could contribute to the relatively high levels they attain in GCF.

Serum and gingival crevicular fluid levels of ciprofloxacin in patients with periodontitis

BACKGROUND

The use of antibiotics as an adjunctive therapy in the treatment of periodontal diseases is of special interest to dental practitioners. In addition to using an appropriate antibacterial agent, clinicians may find it useful to determine the local and systemic concentrations of antibiotics in infected periodontal sites to reduce the levels of bacteria. The purpose of this study was to determine the serum and gingival crevicular fluid, or GCF, concentrations of systemic ciprofloxacin in patients with periodontitis.

METHODS

Ten subjects with chronic periodontitis received ciprofloxacin (500 milligrams) twice daily for five days. The authors collected GCF and serum samples immediately after administering the first dose (baseline = 0 hours) and at consecutive time points. The orifice method was used for GCF sampling, and 5 milliliters of venous blood was drawn for serum analysis. The authors used high-performance liquid chromatography to determine ciprofloxacin concentrations in GCF and serum.

RESULTS

The authors found that ciprofloxacin concentrations in GCF were significantly higher than concentrations in serum at two, four, seven, 24 and 120 hours. Ciprofloxacin reached the maximum concentration, or Cmax (3.72 micrograms/ mL), in GCF two hours after the initial dose was administered. The concentration decreased to 2.06 microg/mL 24 hours after the initial administration of the drug. Serum Cmax was 2.58 microg/mL at 1.5 hours, and the concentration decreased to 0.26 microg/mL at 24 hours.

CONCLUSION

The results of this clinical study show that ciprofloxacin is found in GCF and its concentration in GCF is significantly higher than that in serum.

CLINICAL IMPLICATIONS

Ciprofloxacin may be useful in treating patients with periodontitis because it reaches higher concentrations in GCF than in serum.

Comparison of the pharmacokinetic profiles of two locally administered doxycycline gels in crevicular fluid and saliva

BACKGROUND

Controlled-release delivery systems enable the clinician to extend the half-life period of locally administered antibiotics in gingival crevicular fluid (GCF) significantly. The aim of this split-mouth study was to compare the pharmacokinetic profile of two different doxycycline gels (DOXY and ATRI) for topical subgingival application. Pharmacokinetics of both doxycycline gels were analyzed in GCF and saliva.

METHODS

In 10 patients suffering from severe periodontitis, 10 pairs of contralateral defects (pocket depth > or =5 mm/bleeding on probing or > or =6 mm) were randomly assigned either to the first application of DOXY or ATRI. Fourteen days after the topical application of the first antibiotic gel, the application of the second gel in the contralateral defect took place. Clinical examinations at baseline showed no significant differences between sites treated with DOXY and ATRI. Samples of GCF and saliva were drawn baseline, 2, 5 and 24 h after application, 2, 3, 4, 7, 9 and 11 days after application. Separation and quantitative measurement of both doxycycline-gels was performed with HPLC- and UV-detection at lambda=260 nm.

RESULTS

In saliva specimens, time-dependent changes of mean doxycycline concentration were almost identical for both doxycycline-gels and declined from a maximum 2 h after application (ATRI: 6653.90+/-3096.14 microg/ml; DOXY: 5386.60+/-1542.02 microg/ml [arithmetic mean+/-SEM]) to zero values 9 days after application. In crevicular fluid specimens, sites treated with ATRI exhibited a faster decrease of mean doxycycline concentration (1085.30, 264.00, 273.94, and 258.00 microg/ml measured 2, 5, 24, and 48 h after application) than sites treated with DOXY (1388.38, 1300.40, 803.73, and 235.10 microg/ml). The faster decrease of ATRI compared with DOXY could not be proved to be statistically significantly different.

CONCLUSIONS

Both doxycycline gels showed pharmacokinetics of controlled-release delivery systems.

Is antibiotic resistance in cutaneous propionibacteria clinically relevant? : implications of resistance for acne patients and prescribers

It is well recognized that some patients with acne do not respond adequately to antibiotic therapy. It is important to distinguish antibiotic recalcitrant acne which we would suggest represents acne that shows a diminished response to treatment irrespective of the cause as opposed to 'antibiotic-resistant acne' which is acne that is less responsive to treatment as a direct consequence of skin colonization with resistant propionibacteria. Here we show that antibiotic-resistant acne is not just a theoretical possibility but a real phenomenon that could have important consequences for patients and prescribers. The relationship between skin colonization by antibiotic-resistant propionibacteria and treatment outcomes is a complex one that is explained at the follicular level by physiological differences affecting local drug concentrations. A systematic review of the literature on antibiotic-resistant propionibacteria revealed methodological shortcomings in studies of their prevalence and a paucity of evidence on their clinical significance. Despite the elucidation of resistance mechanisms in cutaneous propionibacteria, our continuing inability to distinguish between strains of Propionibacterium acnes means that we still do not fully understand how resistance spreads, although person-to-person transfer is most likely. Finally, we present a decision tree for acne management in an era of prudent antimicrobial prescribing that provides an alternative to existing treatment algorithms by placing topical retinoids and not antibiotics at the cornerstone of acne management.

Accumulation of ciprofloxacin and minocycline by cultured human gingival fibroblasts

Through a mechanism that is unclear, systemic fluoroquinolones and tetracyclines can attain higher levels in gingival fluid than in blood. We hypothesized that gingival fibroblasts take up and accumulate these agents, thereby enhancing their redistribution to the gingiva. Using fluorescence to monitor transport activity, we characterized the accumulation of fluoroquinolones and tetracyclines in cultured human gingival fibroblast monolayers. Both were transported in a concentrative, temperature-dependent, and saturable manner. Fibroblasts transported ciprofloxacin and minocycline with K(m) values of 200 and 108 micro g/mL, respectively, at maximum velocities of 4.62 and 14.2 ng/min/ micro g cell protein, respectively. For both agents, transport was most efficient at pH 7.2 and less efficient at pH 6.2 and 8.2. At steady state, the cellular/extracellular concentration ratio was > 8 for ciprofloxacin and > 60 for minocycline. Thus, gingival fibroblasts possess active transporters that could potentially contribute to the relatively high levels these agents attain in gingival fluid.

Pharmacokinetic profile of a locally administered doxycycline gel in crevicular fluid, blood, and saliva

BACKGROUND

With the help of so-called controlled release delivery systems, the half-life period of locally administered antibiotics in gingival crevicular fluid (GCF) can be extended significantly. The aim of this study was to characterize the delivery profile of a new one-component 14% doxycycline free amine gel for local application. Pharmacokinetics of doxycycline (DOXY) were analyzed in GCF, saliva, and serum.

METHODS

Twenty patients with persisting or recurring pockets (probing depths > or = 5 mm and bleeding on probing) after mechanical treatment (surgical or non-surgical) took part in the study. In each patient 1 periodontal defect was treated with DOXY gel. Samples of GCF, saliva, and serum were obtained before application of DOXY gel; 15 minutes after application; at 2 and 5 hours; and at 1, 2, 3, 4, 7, 9, and 11 days after application. Separation and quantitative measurement of DOXY was performed with high performance liquid chromatography and UV detection at lambda = 260 nm.

RESULTS

Coefficients of variation were lower than 2% (intraassay) and 4% (interassay), respectively. For concentrations between 50 to 1000 microg/ml, we found a linear relationship between expected and measured DOXY values (linear coefficient of correlation: r = 0.998). Within the first 5 hours after application, concentration of DOXY in GCF (maximum after 15 minutes 19.97 +/- 5.85 mg/ml) and saliva (maximum after 15 minutes 17.83 +/- 2.84 mg/ml) was similar. Then concentration fell to a lower level (28.90 +/- 19.44 microg/ml) compared to GCF (577.41 +/- 127.34 microg/ml) after 3 days. Up to 10 days after application, the concentration of DOXY in GCF was 34.24 microg/ml. With the exception of 1 patient, all serum samples were DOXY-negative.

CONCLUSIONS

1) After subgingival application of biodegradable 14% doxycycline gel, mean doxycycline levels in GCF that exceeded 16 microg/ml could be maintained for at least 12 days. Thus, the antimicrobial agent may be classified as a controlled release device. 2) The antibiotic effect was limited mainly to the subgingival sites of application of the doxycycline gel. 3) The doxycycline gel possesses the pharmacokinetic and clinical properties to deliver efficacious levels of antibiotics to the periodontal pocket and to maintain these levels for at least 1 week without the need of further drug retention by a periodontal dressing.

Long-term treatment with subantimicrobial dose doxycycline exerts no antibacterial effect on the subgingival microflora associated with adult periodontitis

BACKGROUND

The purpose of this study was to determine whether treatment with subantimicrobial dose doxycycline (SDD), 20 mg bid, exerted an antimicrobial effect on the microflora associated with adult periodontitis.

METHODS

Following the approval of the protocol and informed consent forms by the respective IRBs at the University of Florida and West Virginia University, 76 subjects with adult periodontitis were entered and randomly assigned to receive SDD or placebo. A split-mouth design was utilized, with each subject receiving subgingival scaling and root planing (SRP) in two quadrants immediately following baseline data collection, while the remaining two quadrants were left unscaled (non-SRP). Microbial samples were collected prior to treatment, after 3, 6, and 9 months of treatment, and after 3 months of no treatment. The samples were examined by microscopy and by enumeration on selective and non-selective media.

RESULTS

All treatments resulted in statistically significant decreases in the proportions of spirochetes and motile rods (P <0.05) and in an increase in the proportion of coccoid forms (P <0.0001) relative to baseline. No between-treatment differences were detected between the SDD and placebo treatments in either the SRP or non-SRP design, with the exception of the small and large spirochetal groups. The spirochetal proportions present in the SDD group were significantly lower (P<0.05) than the paired placebo group during the 9-month treatment and was preceded by a significant decrease (P<0.01) in the proportion of microbiologic sample sites that bled on probing. No between- treatment differences were detected in any of the other microbial parameters.

CONCLUSION

The microbial differences observed were attributed to the anticollagenase and anti-inflammatory properties of SDD and not to an antimicrobial effect.

Gingival fluid ciprofloxacin levels at healthy and inflamed human periodontal sites

BACKGROUND

Polymorphonuclear leukocytes (PMNs) take up and accumulate ciprofloxacin. This may allow them to enhance the delivery of this agent to the inflamed periodontium.

METHODS

Cross-sectional and longitudinal approaches were used to test the hypothesis. In the cross-sectional study, 7 periodontally healthy adults and 8 adults with untreated periodontitis were administered three doses of ciprofloxacin (500 mg bid). Gingival fluid (GF) and serum samples were obtained after 28 hours and analyzed by high-performance liquid chromatography (HPLC). In the longitudinal study, 8 adult periodontitis subjects were administered 500 mg ciprofloxacin bid for 8 days. After 28 hours, GF from 4 sites with 5 to 8 mm probing depths was sampled in each subject, serum samples were obtained, and 2 of the 4 sites were root planed. GF and serum were sampled again 7 days later (196 hours after the initial dose).

RESULTS

The mean ciprofloxacin levels in the GF and serum of periodontally healthy subjects were 2.52 +/- 0.22 microg/ml and 0.47 +/- 0.05 microg/ml, respectively. In subjects with periodontitis, these levels were 2.69 +/- 0.44 microg/ml and 0.61 +/- 0.13 microg/ml, respectively. GF ciprofloxacin levels were significantly higher than corresponding serum levels in healthy and diseased subjects (P<0.01), but there were no significant differences in GF or serum levels between the 2 subject groups. Since GF flow was significantly higher at diseased sites, however, more ciprofloxacin was distributed to these sites than to healthy sites. In the longitudinal study, GF flow at 196 hours was 16% lower at root planed sites than at untreated control sites (P = 0.412). The minor decrease in this index of inflammation was accompanied by a small (9%), but statistically significant (P= 0.007), decrease in GF ciprofloxacin levels.

CONCLUSIONS

GF ciprofloxacin levels decreased slightly at inflamed periodontal sites after root planing, but were significantly higher than serum levels even at healthy periodontal sites. Inflammation may enhance the distribution of ciprofloxacin to diseased sites, but it is not a major determinant of GF ciprofloxacin levels.

Effect of systemic doxycycline on alveolar bone loss after periradicular surgery

Studies in the periodontic literature have shown an average of 0.5 mm to > 1.0 mm of bone loss after full thickness flap reflection. Similar literature has revealed that the tetracycline family of antibiotics can prevent bone loss. The purpose of this study was to observe the effect of systemic Doxycycline on crestal alveolar bone loss after periradicular surgery in beagle dogs. Five beagle dogs were used in two phases of this study. In the first phase (control sides), after reflecting full thickness flaps in one mandibular quadrant, notches were placed in the enamel of the third and fourth premolar teeth using a one-quarter round bur. Using magnification, measurements were taken from the reference notches to the height of the alveolar crest. After 8 wk, flaps were reflected in the same quadrant and measurements retaken, and the amount of bone loss was then measured. In the second phase (experimental sides), the same procedure was performed on the contralateral mandibular quadrant, but the dogs were placed on 4.4 mg/kg/day of Doxycycline for 10 days after reflections of full thickness flaps. After another 8 wk, the area was reflapped and measured. There was significantly (p < 0.01) less bone loss on the Doxycycline-treated side.

The effects of sustained release doxycycline on the anaerobic flora and antibiotic-resistant patterns in subgingival plaque and saliva

BACKGROUND

The purpose of this study was to determine the effects of periodontal treatment with a sustained-release, biodegradable gel containing 8.5% doxycycline on the anaerobic flora and on antibiotic susceptibility patterns associated with subgingival plaque and saliva.

METHODS

Forty-five subjects with adult periodontitis were entered into a parallel design, single-blind study of 6 months' duration. The subjects were randomized to receive either doxycycline treatment (n = 23) or oral hygiene instruction/reinforcement (n = 22). Saliva and subgingival plaque samples were collected prior to and at 7, 21, 91, and 182 days after initiation of treatment. The proportion of the cultivable flora resistant to 10 microg doxycycline/ml was determined relative to total anaerobic counts, and the 3 most predominant colony types resistant to doxycycline were individually enumerated. A representative of each was subcultured, identified to genus and species level, and tested for its susceptibilities to 6 antibiotics.

RESULTS

A significant decrease (P <0.01) in total anaerobic counts following doxycycline treatment caused a transient increase in the proportion, but not in the actual counts, of doxycycline-resistant bacteria recovered from both plaque and saliva at 7 and 21 days but not at 91 or 182 days. The same doxycycline-resistant taxa were recovered at all sample periods including baseline. Regardless of treatment, the isolates were similarly distributed and belonged to the same bacterial groups.

CONCLUSIONS

Doxycycline treatment significantly reduced the anaerobic population in plaque but did not result in a change in either the number of resistant bacteria present or the acquisition of antibiotic resistance.

The use of locally delivered doxycycline in the treatment of periodontitis. Clinical results

The clinical safety and effectiveness of a subgingivally delivered biodegradable drug delivery system containing doxycycline hyclate (DH) has been evaluated in 3 large 9-month multicenter randomized parallel-design controlled clinical trials. A total of 1002 patients having at least 2 quadrants with a minimum of 4 qualifying pockets > or = 5 mm that bled on probing were enrolled. Each subject had > or = 7 mm probing depths in 2 of the qualifying pockets. Study 1 (n=180) compared DH to sanguinarine chloride (SC) and vehicle control (VC). Study 2 (n=411) and study 3 (n=411) compared DH to VC, scaling and root planing (SRP), and oral hygiene (OH). Clinical measurements included probing depth reduction (PDR), attachment level gain (ALG), bleeding on probing reduction (BOP) and plaque index (PI). Analysis of efficacy data from these 3 trials show all treatments gave significant positive clinical changes from baseline at most time points. Study 1 results indicate that DH was superior to SC and VC in PDR at all time points. Similar results were obtained for ALG when DH was compared to SC and VC. For BOP reductions, DH was superior to VC at all time points and to SC at months 5 through 9. For DH, mean ALG in deep (> or = 7 mm) pockets was 1.4 mm; mean PDR for DH was 2.6 mm. For moderate (5 to 6 mm) pockets, ALG was 0.8 mm and PDR 1.5 mm. Studies 2 and 3 reported mean month 9 ALG for SRP as 0.7 mm and 0.8 mm, respectively. For DH, ALG was 0.8 mm in both studies 2 and 3. At month 9 in studies 2 and 3, 29% and 31% of DH sites and 27% and 34% of SRP sites showed ALG > or = 2 mm. Probing depth reductions followed the same pattern, with 32% of DH sites and 32% of SRP sites showing > or = 2 mm PD reductions in study 2, and 41% of DH and 43% of SRP sites showing PDR of > or = 2 mm in study 3. Comparisons between DH, VC, and OH treatment groups in studies 2 and 3 showed DH treatment was statistically superior to VC and OH at most time points. Results of these 3 large clinical trials demonstrate that treatment of periodontitis with 10% doxycyline hyclate in a bioabsorbable delivery system is equally as effective as SRP and superior in effect to VC and OH in reducing the clinical signs of adult periodontitis.

The use of locally delivered minocycline in the treatment of chronic periodontitis. A review of the literature

Tetracyclines are frequently used in the treatment of periodontitis; however, emergence of resistant bacterial strains has decreased the utility of these drugs. At present, there are a lot of data in the literature from which one can draw conclusions regarding the use of local drug delivery. This paper reviews the utility and different systems of local delivery of minocycline, a semisynthetic tetracycline, in the treatment of periodontitis.

The pharmacokinetic profile of a biodegradable controlled-release delivery system containing doxycycline compared to systemically delivered doxycycline in gingival crevicular fluid, saliva, and serum

The primary goal of this study was to characterize the release profile of doxycycline hyclate (8.5% w/w) from a biodegradable controlled-release delivery system (DH) placed in periodontal pockets. Pharmacokinetic data were obtained from gingival crevicular fluid (GCF), saliva, and serum of adult periodontitis patients. These results were compared to those obtained from individuals who received standard oral doses of doxycycline hyclate (200 mg on day 0, then 100 mg/day for 7 days). All participants presented with multiple pockets > or = 5 mm that bled upon probing. At the baseline visit patients receiving local drug delivery had all pockets > or = 5 mm that bled upon probing on one side of the mouth filled with DH. Drug retention was enhanced with 1 of 2 periodontal dressings (non-eugenol [NE] or 2-octyl cyanoacrylate [2-octyl]). Doxycycline concentrations were analyzed with the aid of reverse phase high performance liquid chromatography. GCF saliva, and serum samples were obtained just prior to drug delivery and then at hours 2, 4, 6, 8, 18, 24 and days 2, 3, 5, 7, and 8. GCF and saliva samples were also obtained at days 10, 14, 21, and 28. Thirty two subjects participated in the study; 13 in the NE group, 13 in the 2-octyl group, and 6 in the group taking oral doxycycline. The release of doxycycline in the GCF peaked at 2 hours (1473 microg/ml in the NE group, and 1986 microg/ml in the 2-octyl group). The mean concentration at day 7 was 309 microg/ml for the NE group and 148 microg/ml for the 2-octyl group. Minimal levels of drug were detected in the GCF of the oral doxycycline group with a peak concentration of 2.53 microg/ml at 12 hours. Salivary concentrations for both local delivery groups peaked at hour 2 (4.05 microg/ml for the NE group and 8.78 microg/ml for the 2-octyl group); by the end of day 1 levels were < or = 2 microg/ml. For subjects who took the oral doxycycline, salivary concentrations never exceeded 0.11 microg/ml. Serum concentrations of doxycycline for individuals receiving the local drug delivery never exceeded 0.1 microg/ml. For the oral doxycycline group serum concentrations ranged from 0.91 to 2.26 microg/ml over the 8 days data were collected. The high concentration of drug available at the treated sites coupled with the relatively low levels in the saliva and almost non-existent levels in the serum indicate that this biodegradable controlled-release delivery system displays an appropriate pharmacokinetic profile for the delivery of doxycycline into periodontal pockets.

Tetracycline and its analogues: a therapeutic paradigm in periodontal diseases

This article discusses the use of tetracyclines in the clinical management of periodontal infections. A review of the drugs pharmacology, pharmacokinetics, and potential adverse effects shows that they are relatively safe if used in appropriate dosages and under controlled conditions. Current data suggest that the routine use of tetracyclines in conjunction with the treatment of periodontitis is unnecessary. However, their distinctive characteristics can be utilized in different delivery systems as an adjunctive aid to conventional treatment of juvenile and refractory forms of periodontitis.

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.

Multi-center comparative evaluation of subgingivally delivered sanguinarine and doxycycline in the treatment of periodontitis. II. Clinical results

The clinical safety and effectiveness of a subgingivally delivered biodegradable drug delivery system containing either 10% doxycycline hyclate (DH), 5% sanguinarium chloride (SC) or no agent (VC) was evaluated in a 9-month multi-center trial. The study was a randomized parallel design with 180 patients who demonstrated moderate to severe periodontitis. All patients had at least two quadrants with a minimum of four qualifying pockets > or = 5 mm that bled on probing. Two of the qualifying pockets were required to be > or = 7 mm. At baseline and at 4 months all qualified sites were treated with the test article administered via syringe. Probing depth reduction (PDR), attachment level gain (ALG), bleeding on probing reduction (BOP), and plaque index were determined monthly. Analysis of efficacy data from the 173 efficacy-evaluable patients indicated that all treatments gave significant positive clinical changes from baseline at all subsequent timepoints. DH was superior to SC and VC in PDR at all timepoints (P < or = 0.01 to 0.001) with a maximum reduction of 2.0 mm at 5 months. For ALG, DH was superior to VC at months 2, 3, 4, 5, 6, 8, and 9 (P < or = 0.04 to 0.002) and superior to SC at months 5, 6, 7, 8, and 9 (P < or = 0.01 to 0.001) with a maximum ALG of 1.2 mm at 6 months. For BOP reduction, DH was superior to VC at all time points (P < or = 0.05) and to SC at months 3, 5, 6, 8, and 9 (P < or = 0.03). For DH, the maximum ALG in deep (> or = 7 mm) pockets was 1.7 mm and PDR 2.9 mm compared to 0.8 mm and 1.6 mm, respectively for moderate (5 to 6 mm) pockets. Test articles were applied without anesthesia and no serious adverse events occurred in the trial. The results of this study indicate that 10% doxycycline hyclate delivered in a biodegradable delivery system is an effective means of reducing the clinical signs of adult periodontitis and exhibits a benign safety profile.

A clinical evaluation of demineralized freeze-dried bone allograft in combination with tetracycline in the treatment of periodontal osseous defects

The purpose was to evaluate the use of demineralized freeze-dried bone allograft reconstituted with 50 mg/ml tetracycline hydrochloride in the treatment of intrabony periodontal defects. Fifteen systemically healthy patients (12 females, 3 males; aged 35 to 61) with moderate-advanced periodontitis were treated. Patients had 3 osseous defects with probing depths (PD) > 5 mm after initial therapy. Each site in each subject was randomly assigned to one of the following groups: 1) demineralized freeze-dried bone allograft reconstituted with 50 mg/ml tetracycline (DFDBA + TCN); 2) demineralized freeze-dried bone allograft alone (DFDBA); or 3) debridement only (D). Clinical measurements were taken the day of surgery, 6 months, and 1 year. Standardized radiographs were taken at baseline and 1 year and were evaluated by computer assisted densitometric image analysis (CADIA). Clinical measurements included gingival recession, PD, clinical attachment level, and mobility. Osseous defect measurements were taken at baseline and at the 1 year reentry. No adverse healing responses occurred. The results showed that all patients had a statistically significant improvement in probing depth and attachment level at 1 year. Osseous measurements showed bone fill of 2.27 mm (51.6%) for the DFDBA + TCN group, 2.20 mm (52.4%) for the DFDBA group, and 1.27 mm (32.8%) for the D group. Defect resolution was 77.3% for the DFDBA + TCN group, 77.9% for the DFDBA group, and 63.8% for the D group. The mean CADIA values were 5.04 for the DFDBA + TCN group, 6.79 for the DFDBA group and 2.78 for the D group. The CADIA values did not correlate with the clinical parameters. Although the grafted groups showed greater bone fill and defect resolution, there was no statistically significant difference in any of the clinical parameters between the treatment groups. This study suggests that there is no significant benefit from reconstituting the allograft with 50 mg/ml of tetracycline hydrochloride.

Concentrations of tinidazole in gingival crevicular fluid and plasma in dogs after multiple dose administration

Tinidazole 15 mg/kg was administered to eight Beagle dogs with gingivitis or periodontitis twice daily for 3 days. Tinidazole concentrations in blood and gingival crevicular fluid (GCF) were measured 1, 3, 6 and 9 h after the morning dose each day. The concentration of tinidazole was determined by high performance liquid chromatography (HPLC). The mean concentration of tinidazole in GCF for each dog ranged from 6.05 to 9.32 micrograms/mL at different time points after the first dose, and on the first day the highest concentration was observed 6 h after the drug administration. Tinidazole concentrations were 34 +/- 4%-72 +/- 9% (mean +/- SEM) of simultaneous plasma concentration. At steady-state, on the third treatment day, the mean tinidazole concentrations in GCF ranged from 6.68 to 13.1 micrograms/mL, i.e. 44 +/- 6%-75 +/- 25% of the corresponding concentrations in plasma. Tinidazole concentration in GCF exceeded the MIC values for putative path-ogenic periodontal bacteria and it is concluded that, when indicated, tinidazole could be used for chemotherapy of periodontitis in dogs.