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

Bacteremia Prevention during Periodontal Treatment-An In Vivo Feasibility Study

The link between periodontitis and systemic diseases has increasingly become a focus of research in recent years. In this context, it is reasonable-especially in vulnerable patient groups-to minimize bacteremia during periodontal treatment. The aim of the present in vivo feasibility study was to investigate the possibility of laser-based bacteremia prevention. Patients with stage III, grade B generalized periodontitis were therefore treated in a split-mouth design either with prior 445 nm laser irradiation before nonsurgical periodontal therapy or without. During the treatments, clinical (periodontal measures, pain sensation, and body temperature), microbiological (sulcus samples and blood cultures before, 25 min after the start, and 10 min after the end of treatment), and immunological parameters (CRP, IL-6, and TNF-α) were obtained. It was shown that periodontal treatment-related bacteremia was detectable in both patients with the study design used. The species isolated were Schaalia georgiae, Granulicatella adiacens, and Parvimonas micra. The immunological parameters increased only slightly and occasionally. In the laser-assisted treatments, all blood cultures remained negative, demonstrating treatment-related bacteremia prevention. Within the limitations of this feasibility study, it can be concluded that prior laser disinfection can reduce bacteremia risk during periodontal therapy. Follow-up studies with larger patient numbers are needed to further investigate this effect, using the study design presented here.

Nanotechnology for Dentistry: Prospects and Applications

In the XXI century, application of nanostructures in oral medicine has become common. In oral medicine, using nanostructures for the treatment of dental caries constitutes a great challenge. There are extensive studies on the implementation of nanomaterials to dental composites in order to improve their properties, e.g., their adhesive strength. Moreover, nanostructures are helpful in dental implant applications as well as in maxillofacial surgery for accelerated healing, promoting osseointegration, and others. Dental personal care products are an important part of oral medicine where nanomaterials are increasingly used, e.g., toothpaste for hypersensitivity. Nowadays, nanoparticles such as macrocycles are used in different formulations for early cancer diagnosis in the oral area. Cancer of the oral cavity-human squamous carcinoma-is the sixth leading cause of death. Detection in the early stage offers the best chance at total cure. Along with diagnosis, macrocycles are used for photodynamic mechanism-based treatments, which possess many advantages, such as protecting healthy tissues and producing good cosmetic results. Application of nanostructures in medicine carries potential risks, like long-term influence of toxicity on body, which need to be studied further. The introduction and development of nanotechnologies and nanomaterials are no longer part of a hypothetical future, but an increasingly important element of today's medicine.

In vitro study of nanoliposomes containing curcumin and doxycycline for enhanced antimicrobial photodynamic therapy against Aggregatibacter actinomycetemcomitans

The excessive inappropriate use of systemic antibiotics has contributed to the emergence of antibiotic-resistant pathogens, which pose a significant risk to the success of treatment. This study has approached this problem by developing doxycycline-loaded liposome doped with curcumin (NL-Cur^+Dox) for combination antibacterial therapy against Aggregatibacter actinomycetemcomitans. The characterization of formulation revealed encapsulation of both drugs in NL-Cur^+Dox with an average size of 239 nm and sustained release behavior. Transmission electron microscopy analysis confirmed the vesicular-shaped nanocarriers without any aggregation or crystallization. The cytotoxic and hemolytic activities of NL-Cur^+Dox were evaluated. The anti-biofilm and anti-metabolic effects of NL-Cur^+Dox -mediated antimicrobial photodynamic therapy (aPDT) were examined. The data indicated that NL-Cur^+Dox -mediated aPDT led to a significant reduction of biofilm (82.7%, p = 0.003) and metabolic activity (75%, p < 0.001) of A. actinomycetemcomitans compared to the control. NL-Cur^+Dox had no significant cytotoxicity to human gingival fibroblast cells under selected conditions (p = 0.074). In addition, the hemolytic activity of NL-Cur^+Dox were negligible (< 5%). These findings demonstrate the potential application of such potent formulations in reducing one of the main bacteria causing periodontitis where the NL-Cur^+Dox could be exploited to achieve an improved phototherapeutic efficiency.

Relevance of Biofilm Models in Periodontal Research: From Static to Dynamic Systems

Microbial biofilm modeling has improved in sophistication and scope, although only a limited number of standardized protocols are available. This review presents an example of a biofilm model, along with its evolution and application in studying periodontal and peri-implant diseases. In 2011, the ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) research group at the University Complutense of Madrid developed an in vitro biofilm static model using representative bacteria from the subgingival microbiota, demonstrating a pattern of bacterial colonization and maturation similar to in vivo subgingival biofilms. When the model and its methodology were standardized, the ETEP research group employed the validated in vitro biofilm model for testing in different applications. The evolution of this model is described in this manuscript, from the mere observation of biofilm growth and maturation on static models on hydroxyapatite or titanium discs, to the evaluation of the impact of dental implant surface composition and micro-structure using the dynamic biofilm model. This evolution was based on reproducing the ideal microenvironmental conditions for bacterial growth within a bioreactor and reaching the target surfaces using the fluid dynamics mimicking the salivary flow. The development of this relevant biofilm model has become a powerful tool to study the essential processes that regulate the formation and maturation of these important microbial communities, as well as their behavior when exposed to different antimicrobial compounds.

Physicochemical properties, metalloproteinases inhibition, and antibiofilm activity of doxycycline-doped dental adhesive

OBJECTIVES

To evaluate the incorporation of doxycycline (DOX) into a commercial dental adhesive regarding physicochemical properties, microtensile bond strength (μTBS), nanoleakage (NL), nanohardness (NH) and Young's modulus (YM), metalloproteinases (MMP) inhibition, and antibiofilm activity.

METHODS

DOX was incorporated into the adhesive at 0.05, 0.1, 0.5, and 1 wt%. Restored teeth were evaluated for μTBS, NL, NH, and YM after 24 -hs and 1-year of water storage. Biofilms of Streptococcus mutans were grown on top of these adhesives and determined for bacterial viability and amount of biomass. The inhibitory effect on MMP was analyzed by in situ zymography under confocal microscopy.

RESULTS

Adhesives with 0.5 and 1 wt% of DOX presented reduced pH and degree of conversion. The incorporation of DOX did not affect μTBS and hybrid layer YM. The control group (no DOX) had a decrease in μTBS and the densest silver nitrate areas after 1-year storage. Hybrid layer NH values increased with 0.1 wt% DOX compared to control and 1 wt% DOX groups, at 24 -hs. After 1-year storage, NH of 1 wt% DOX adhesive decreased compared to the control group. The 0.5 and 1 wt% concentrations of DOX decreased the bacterial viability and the biofilm biomass. Confocal images suggest an increased MMP inhibition proportional to the percentage of DOX.

CONCLUSION

At any concentration, DOX-doped dental adhesives were able to inhibit MMP activity, diminish nanoleakage, and maintain the resin-dentin bond-strength after 1 year of artificial aging.

CLINICAL SIGNIFICANCE

Doxycycline-doped dental adhesive inhibited metalloproteinases activity and preserved interface bond strength. This formulation has a potential to improve adhesive restorations clinical longevity.

Doxycycline-functionalized polymeric nanoparticles inhibit Enterococcus faecalis biofilm formation on dentine

AIM

To evaluate in a laboratory setting the antimicrobial properties and the potential to inhibit biofilm formation of novel remineralizing polymeric nanoparticles (NPs) when applied to dentine surfaces and to ascertain the effect of the functionalization of these NPs with zinc, calcium or doxycycline.

METHODOLOGY

The antimicrobial activity and inhibition of biofilm formation of polymeric NPs were analysed on human dentine blocks that were infected with Enterococcus faecalis before or after application of NPs. LIVE/DEAD ® testing under Confocal Laser Scanning Microscopy and bacterial culturing were employed to analyse biofilm biovolume and bacterial viability. Field Emission Scanning Electron Microscopy was also employed to assess biofilm morphology. One-way anova with Welch's correction and post hoc comparison by the Games-Howell test were performed for comparisons between groups.

RESULTS

The un-functionalized NPs displayed the greatest antimicrobial activity against E. faecalis biofilms as they provided the lowest biovolume (3865.7 ± 2926.97 µm³ ; P < 0.001) and the highest dead/injured cells percentage (79.93 ± 18.40%; P < 0.001), followed by Dox-NPs (biovolume: 19,041.55 ± 17,638.23 µm³ , dead/injured cells: 45.53 ± 26.50%; P < 0.001). Doxycycline-loaded NPs had the largest values of inhibition of biofilm formation with the lowest biofilm biovolume (8517.65 ± 7055.81 µm³ ; P < 0.001) and a high dead/injured bacterial percentage (68.68 ± 12.50%; P < 0.001). Un-functionalized NPs did not reduce biomass growth (P > 0.05), but attained the largest percentage of compromised cells (93 ± 8.23%; P < 0.001), being able to disrupt biofilm formation. It also produced occlusion of dentinal tubules, potentially interfering with bacterial tubule penetration.

CONCLUSIONS

A new generation of bioactive nano-fillers (doxycycline-functionalized polymeric NPs) had antibacterial activity and occluded dentinal tubules. Incorporating these NPs into endodontic sealers may have the potential to enhance the outcome of root canal treatment.

Polymeric nanoparticles protect the resin-dentin bonded interface from cariogenic biofilm degradation

The objective was to assess doxycycline (Dox) and zinc (Zn) doped nanoparticles' (NPs) potential to protect the resin-dentin interface from cariogenic biofilm. Three groups of polymeric NPs were tested: unloaded, loaded with zinc and with doxycycline. NPs were applied after dentin etching. The disks were exposed to a cariogenic biofilm challenge in a Drip-Flow Reactor during 72 h and 7 d. Half of the specimens were not subjected to biofilm formation but stored 72 h and 7 d. LIVE/DEAD® viability assay, nano-dynamic mechanical assessment, Raman spectroscopy and field emission electron microscopy (FESEM) analysis were performed. The measured bacterial death rates, at 7 d were 46% for the control group, 51% for the undoped-NPs, 32% for Dox-NPs, and 87% for Zn-NPs; being total detected bacteria reduced five times in the Dox-NPs group. Zn-NPs treated samples reached, in general, the highest complex modulus values at the resin-dentin interface over time. Regarding the mineral content, Zn-NPs-treated dentin interfaces showed the highest mineralization degree associated to the phosphate peak and the relative mineral concentration. FESEM images after Zn-NPs application permitted to observe remineralization of the etched and non-resin infiltrated collagen layer, and bacteria were scarcely encountered. The combined antibacterial and remineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Dox-NPs exerted an antibacterial role but did not remineralize the bonded interface. Undoped-NPs did not improve the properties of the interfaces. Application of Zn-doped NPs during the bonding procedure is encouraged. STATEMENT OF SIGNIFICANCE: Application of Zn-doped nanoparticles on acid etched dentin reduced biofilm formation and viability at the resin-dentin interface due to both remineralization and antibacterial properties. Doxycycline-doped nanoparticles also diminished oral biofilm viability, but did not remineralize the resin-dentin interface.

Novel Polymeric Nanocarriers Reduced Zinc and Doxycycline Toxicity in the Nematode Caenorhabditis elegans

The objective was to evaluate the toxicity of zinc- and doxycycline-loaded polymeric nanoparticles (NPs) using Caenorhabditis elegans as a model organism. These NPs are composed of ethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate and methacrylic acid. NPs were loaded with doxycycline (D-NPs) and zinc (Zn-NPs) by chemical adsorption, and loading efficacy was demonstrated. Worm death rate in a concentration-response curve basis was calculated for lethality. Metabolism was evaluated through pharyngeal pumping assay. Body length measurements, brood size and egg lays were used to gauge growth, reproduction and fertility respectively. Intracellular hydrogen peroxide levels were determined to assess the reactive oxygen species production. One-way ANOVA and Bonferroni were used for comparisons (p < 0.05). Tested NPs at the highest dosage did not affect lethality or worm metabolism, expressed in terms of death rate and pharyngeal pumping per minute, respectively. Zn-NPs slightly increased worm growth. The concentration of the intracellular hydrogen peroxide levels was the lowest in the D-NPs group. The distinct NPs and concentrations employed were shown to be non-toxic for in situ administration of zinc and doxycycline, reducing the harmful effects of these compounds.

A New Controlled-Release Material Containing Metronidazole and Doxycycline for the Treatment of Periodontal and Peri-Implant Diseases: Formulation and In Vitro Testing

Background

Several locally administered antimicrobials have been studied in the literature as adjunctive or primary treatments for periodontitis and peri-implantitis with conflicting results.

Objective

The aim of this study was twofold: (1) the formulation of a controlled-release material containing metronidazole and doxycycline; (2) an in vitro evaluation of its antibacterial properties against planktonic and biofilm species involved in periodontal and peri-implant diseases.

Methods

Doxycycline (10 mg/ml) and metronidazole (20 mg/ml) were incorporated into a hydroxyethylcellulose-polyvinylpyrrolidone-calcium polycarbophil gel. Three milliliters of gel were dialyzed against Dulbecco's phosphate-buffered saline for 13 days. Antibiotics release at 3, 7, 10, and 13 days was determined spectroscopically. The inhibitory activity of the experimental gel was tested against A. actinomycetemcomitans, S. sanguinis, P. micra, and E. corrodens with an agar diffusion test, an inactivation biofilm test, and a confocal laser scanning microscope study (CLSMS) for S. sanguinis up to 20 days.

Results

After 13 days, the released doxycycline was 9.7% (at 3 days = 1.2 mg; 7 days = 0.67 mg; 10 days = 0.76 mg; 13 days = 0.29 mg), while metronidazole was 67% (30 mg, 6.8 mg, 2.5 mg, and 0.9 mg at the same intervals). The agar diffusion test highlights that the formulated gel was active against tested microorganisms up to 312 h. Quantitative analysis of biofilm formation for all strains and CLSMS for S. sanguinis showed a high growth reduction up to 13 days.

Conclusions

The in vitro efficacy of the newly formulated gel was confirmed both on planktonic species and on bacterial biofilm over a period of 13 days. The controlled-release gel containing metronidazole and doxycycline had an optimal final viscosity and mucoadhesive properties. It can be argued that its employment could be useful for the treatment of periodontal and peri-implant diseases, where conventional therapy seems not successful.

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.

Modified Polymeric Nanoparticles Exert In Vitro Antimicrobial Activity Against Oral Bacteria

Polymeric nanoparticles were modified to exert antimicrobial activity against oral bacteria. Nanoparticles were loaded with calcium, zinc and doxycycline. Ions and doxycycline release were measured by inductively coupled plasma optical emission spectrometer and high performance liquid chromatography. Porphyromonas gingivalis, Lactobacillus lactis, Streptoccocus mutans, gordonii and sobrinus were grown and the number of bacteria was determined by optical density. Nanoparticles were suspended in phosphate-buffered saline (PBS) at 10, 1 and 0.1 mg/mL and incubated with 1.0 mL of each bacterial suspension for 3, 12, and 24 h. The bacterial viability was assessed by determining their ability to cleave the tetrazolium salt to a formazan dye. Data were analyzed by ANOVA and Scheffe’s F (p < 0.05). Doxycycline doping efficacy was 70%. A burst liberation effect was produced during the first 7 days. After 21 days, a sustained release above 6 µg/mL, was observed. Calcium and zinc liberation were about 1 and 0.02 µg/mL respectively. The most effective antibacterial material was found to be the Dox-Nanoparticles (60% to 99% reduction) followed by Ca-Nanoparticles or Zn-Nanoparticles (30% to 70% reduction) and finally the non-doped nanoparticles (7% to 35% reduction). P. gingivalis, S. mutans and L. lactis were the most susceptible bacteria, being S. gordonii and S. sobrinus the most resistant to the tested nanoparticles.

Application of bioelectric effect to reduce the antibiotic resistance of subgingival plaque biofilm: An in vitro study

Context:

Biofilms are known for their antimicrobial resistance, and so is the subgingival plaque biofilm, the primary etiologic factor for periodontal infections.

Aims:

The objective of this study is to investigate if the subgingival plaque biofilm resistance can be reduced using doxycycline in the presence of low-intensity electric field (bioelectric effect).

Settings and Design:

The study was an in vitro microbiological study.

Materials and Methods:

Subgingival plaque samples from chronic periodontitis patients were collected to grow subgingival plaque biofilms on hydroxyapatite disks. Hydroxyapatite disks with the plaque biofilms from each patient were divided into four groups: (i) No intervention – control, (ii) current alone – CU; (iii) doxycycline – AB, and (iv) combined treatment – CU + AB. After respective treatments, the disks were anaerobically incubated for 48 h, the biofilm was dispersed and subcultured and colony-forming unit/mL was estimated in all the four groups.

Statistical Analysis:

Statistical analysis was done using Mann–Whitney and Kruskal–Wallis tests for intergroup comparisons. T-test was done to assess the difference in current flow between the groups CU and CU + AB.

Results:

All the three treatment modalities showed antibacterial effect. Application of current alone resulted in reduced bacterial growth than control group. Doxycycline alone resulted in reduction in bacterial counts better than control and current alone groups. The combination treatment showed greatest inhibition of bacterial colonies.

Conclusion:

The ability of doxycycline antibiotic in inhibiting plaque biofilm was significantly enhanced by application of a weak electric field (5 volts for 2 min).

In vitro activity of taurolidine gel on bacteria associated with periodontitis

OBJECTIVES

The purpose of this in vitro study was to determine the antimicrobial activity of two different taurolidine gel formulations in comparison with minocycline microspheres.

METHODS

Three percent taurolidine gel (TLG3) and 2 % taurolidine gel (TLG2) were compared to minocycline microspheres (MINO) against single bacterial species and a 12-species-mixture. The antimicrobial activity was proven by determination of minimal inhibitory concentrations (MICs), killing assays, after exposure of the antimicrobials as well as within a biofilm.

RESULTS

The MICs against the single species were between 0.5 and 2 mg/ml of taurolidine. MICs of the used mixed microbiota were 1.5 mg/ml (TLG3) and 4 mg/ml (TLG2). Fusobacterium nucleatum and Porphyromonas gingivalis were completely killed by 10 % TLG3 and TLG2 (equivalent to 3 and 2 mg/ml taurolidine) after 6 h. The mixture of 12 species was not completely killed by any of the test substances. Taurolidine gels showed a post-antimicrobial activity, however being less than that of MINO. On biofilms, taurolidine gels reduced concentration dependently the colony forming unit (CFU) counts (multi-species biofilms by 3.63 log10 after 100 % (30 mg/ml) of TLG3), reductions were 2.12 log10 after MINO (1000 μg/ml minocycline).

CONCLUSIONS

Taurolidine gel formulations exert antimicrobial activity against bacteria associated with periodontal disease. Nevertheless, a complete elimination of biofilms seems to be impossible and underlines the importance of mechanical removal of biofilms prior to application of the antimicrobial.

CLINICAL RELEVANCE

Taurolidine gels may represent a potential alternative for adjunctive topical antimicrobial treatment in periodontitis and infectious peri-implant diseases.

Characterization of the release profile of doxycycline by PLGA microspheres adjunct to non-surgical periodontal therapy

The aim of this pilot study was to assess the release of locally delivered doxycycline by poly (l-lactide-co-glycolide) (PLGA) microspheres in the periodontal pocket of patients with chronic periodontitis, treated by non-surgical periodontal therapy. Nineteen sites of non-adjacent teeth of four different patients were evaluated. Five milligram of PLGA microspheres loaded with 16 doxycycline hyclate (DOX) was administered per periodontal site. To quantify DOX released into the periodontal pocket, gingival crevicular fluid (GCF) was collected from the sites on days 2, 5, 7, 10, 15, and 20 after DOX application, and high-performance liquid chromatography was performed. Data were statistically assessed by ANOVA/Tukey test. At days 2, 5, and 7, the DOX concentration was stably sustained (23.33 ± 1.38, 23.4 ± 1.82, and 22.75 ± 1.33 μg/mL, respectively), with no significant differences over these assessment times (p > 0.05). At days 10 and 15, a tendency was observed toward a decrease in DOX concentration (21.74 ± 0.91 and 20.53 ± 4.88 μg/mL, respectively), but a significant decrease in GCF drug concentration (19.69 ± 4.70 μg/mL) was observed only on day 20. The DOX delivery system developed demonstrated a successful sustained release after local administration, as an adjunct to non-surgical periodontal therapy.

A chlorhexidine-loaded biodegradable cellulosic device for periodontal pockets treatment

Absorbent points widely used in endodontic therapy were transformed into bioresorbable chlorhexidine delivery systems for the treatment of the periodontal pocket by preventing its recolonization by the subgingival microflora. These paper points (PPs) were first oxidized to promote their resorption, then grafted with β-cyclodextrin (CD) or maltodextrin (MD) in order to achieve sustained delivery of chlorhexidine. We investigated the oxidation step parameters through the time of reaction and the nitric and phosphoric acid ratios in the oxidizing mixture, and then the dextrin grafting step parameters through the time and temperature of reaction. A first selection of the appropriate functionalization parameters was undertaken in relation to the degradation profile kinetics of the oxidized (PPO) and oxidized-grafted samples (PPO-CD and PPO-MD). Samples were then loaded with chlorhexidine digluconate (digCHX), a widely used antiseptic agent in periodontal therapy. The release kinetics of digCHX from PPO-CD and PPO-MD samples were compared to PP, PPO and to PerioChip(®) (a commercial digCHX containing gelatine chip) in phosphate buffered saline (pH 7.4) by ultraviolet spectrophotometry. The cytocompatibility of the oxidized-grafted PP was demonstrated by cell proliferation assays. Finally, the disc diffusion test from digCHX loaded PPO-MD samples immersed in human plasma was developed on pre-inoculated agar plates with four common periodontal pathogenic strains: Fusobacterium nucleatum, Prevotella melaninogenica, Aggregatibacter actinomycetem comitans and Porphyromonas gingivalis. To conclude, the optimized oxidized-dextrin-grafted PPs responded to our initial specifications in terms of resorption and digCHX release rates and therefore could be adopted as a reliable complementary periodontal therapy.

Periodontal pharmacotherapy - an updated review

Periodontal disease is mainly associated with the activity of bacteria which adhere to the tooth surface and form specific structure of bacterial biofilm. Periodontal bacteria cause inflammation of the gums and aggressive immune response, affecting the periodontium. The first phase of initial therapy - mechanical removal of dental plaque and calculus - is necessary. If this non-surgical therapy has proved to be unsuccessful, an alternative treatment with antimicrobial agents is then considered. Pharmacotherapy is based on systemic or local antibiotics and/or antiseptics, which are applied according to the severity of the disease. A number of recent periodontal studies present some of the pharmacological agents, that are directed against bacteria or a host immune response, are often chosen as an adjunct treatment option, but none of these antimicrobials were established as 'a gold standard' in the periodontal treatment. This review provides some present recommendation of pharmacological strategies, with particular emphasis on systemic and local antimicrobial therapy of periodontal disease.

Multiple applications of flurbiprofen and chlorhexidine chips in patients with chronic periodontitis: a randomized, double blind, parallel, 2-arms clinical trial

AIM

The aim of the present randomized, double blind, parallel, 2-arm clinical study was to examine the safety and efficacy of frequent applications of chlorhexidine chip (CHX) and flurbiprofen chip (FBP) in patients with chronic periodontitis.

METHODS

Sixty patients were randomized into CHX and FBP groups. Following OHI and scaling and root planing (SRP), baseline pocket depth (PD) measurements, gingival recession and bleeding on probing (BOP) were performed and repeated at week 4 and 8. The assigned chip was placed at weeks 0, 1, 2, 3, 5, 7.

RESULTS

Mean PD reduction in the CHX group was 2.08 mm (7.17 to 5.09, p < 0.0001). Mean PD reduction in the FBP group was 2.27 mm (6.72 to 4.45, p < 0.0001). Ninety-seven percentage and 95% of these sites exhibited PD reduction ≥1 mm, while 38% and 34% of the sites exhibited PD ≥3 mm (FBP and CHX, respectively). Clinical attachment level gain (1.66 and 1.95 mm, respectively) was statistically significant (p < 0.0001). Baseline BOP dropped from 98% and 100% to 24% and 30% for the CHX and FBP groups, respectively (p < 0.0001).

CONCLUSION

Frequent applications of CHX and FBP chips resulted in a significant improvement in the periodontal condition in these sites. Furthermore studies will be required to compare this new treatment regimen to SRP or SRP with single chip application.

The effect of locally delivered doxycycline as an adjunctive therapy to scaling and root planing in smokers

BACKGROUND

Locally delivered doxycycline is found to be effective in managing periodontitis as an adjunct to scaling and root planing.

AIM

To evaluate the effect of locally delivered doxycycline (10%) with scaling and root planing in the periodontal treatment of smokers and to compare it with scaling and root planing alone.

METHODS

Twelve smokers with chronic periodontitis and a pocket depth (⩾5 mm) on posterior teeth that bleed on probing were selected. Patients were randomly assigned to scaling and root planing (SRP) or scaling and root planing followed by local application of doxycycline (SRP-D). Plaque, bleeding on probing, gingival recession, clinical attachment level (CAL), and probing depth (PD) were recorded at the baseline, 6 and 12 weeks.

RESULTS

Both groups showed a significant reduction in Plaque, Bleeding on Probing and pocket depth at 6th and 12th week from the baseline. A statistically significant gain of attachment was observed in both groups after treatment. Even though the doxycycline group showed slightly higher attachment gain it was not statistically significant compared to the control group.

CONCLUSION

The observations of the study reveal that the additional benefit of topical application of doxycycline as an adjunct to scaling and root planing in smokers is not convincing. However, further clinical studies may be necessary to substantiate the present observations.

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.

Safety and Efficacy Review of Doxycycline

Doxycycline is a member of the tetracycline class of antibiotics and has been used clinically for more than 40 years. It is a well-tolerated drug that is bacteriostatic and acts via the inhibition of bacterial ribosomes. It is generally given at a dose of 100-mg daily or twice daily. It is well absorbed and has generally good tissue penetration. The serum half-life is 18-22 hours and dosage does not need to be adjusted in the presence of renal or hepatic impairment. Major side effects are gastro-intestinal and dermatological and it is generally contra-indicated in pregnancy or childhood because of concerns about discolouration of developing teeth and potential effects on growing bones. Drug interactions are not common although can occur with the concomitant use of methotrexate and the oral contraceptive pill, and its absorption can be reduced by the co-administration with some antacids and iron preparations. It has activity against many organisms, including Gram-positives, Gram-negatives and atypical bacteria. In addition, it appears to have some potentially clinically useful anti-inflammatory properties.

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

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

Nonsurgical and surgical periodontal therapy in single-rooted teeth

The purpose of this study was to compare the effect of tooth related and patient related factors on the success of non-surgical and surgical periodontal therapy. In 41 patients (22 female) with untreated and/or recurrent periodontitis, no therapy, scaling and root planing (SRP), or access flap (AF) were assigned according to probing pocket depth (PPD). PPD and vertical relative attachment level (RAL-V) were obtained initially, 3 and 6 months after therapy. Baseline data were compared according to therapy, jaw, tooth type, and site. Factors influencing clinical parameters were identified using multilevel analyses. Baseline PPDs were deeper interproximally, in the maxilla and at premolars compared to buccal/oral sites, mandibular, and anterior teeth. At 6 months, PPD reduction and RAL-V gain were significantly greater at sites receiving SRP and AF as compared to untreated sites (p < 0.001). PPD reduction and RAL-V gain were significantly less (p < 0.005) in smokers as compared to nosmokers and at interproximal sites (p < 0.0001) as compared to buccal/oral sites. RAL-V gain was less in aggressive periodontitis, and PPD reduction was less in the maxilla (p < 0.001). In sites with greater bone loss and infrabony defects, a poorer response was observed regarding RAL-V gain or PPD reduction, respectively. The conclusions of the study are the following: (1) Nonsurgical and surgical periodontal therapies are effective in single-rooted teeth; (2) severe interproximal bone loss and infrabony defects deteriorate clinical results; and (3) there seem to be more defect-associated (tooth, site) factors influencing treatment outcome than patient-associated factors.

A comparative study of systemic subantimicrobial and topical treatment of minocycline in experimental periodontitis of rats

OBJECTIVE

The purpose of this study was to compare the effectiveness of minocycline on treating experimentally induced periodontitis in rats when administered either as a systemic subantimicrobial dose or as a topical ointment.

DESIGN

Thirty-two adult male Sprague-Dawley rats in four experimental groups-(1) model group; (2) systemic subantimicrobial dose of minocycline (5mg/kg/day) treatment group; (3) topical subgingival dose of minocycline (2mg/animal/week) treatment group; (4) control group. Experimentally induced periodontitis-silk ligatures were placed around the crevices of the second molar teeth and the animals fed a 10% sucrose drink. Assessment was carried out at days 28 and 56 using a number of different visual, histological and ultrastructure approaches. (1) Visual assessment-tooth mobility, gingival index and alveolar bone loss. (2) Histological examination-monocyte infiltration and resorption lacunae with osteoclasts. (3) Transmission electron microscopy (TEM)-morphological transformation of fibroblasts and osteoclasts. The collected data were analysed for statistical significance using the analysis of variance statistical test.

RESULTS

Minocycline significantly reduced tooth mobility, gingival index and alveolar bone loss when administered either systemically or as a topical ointment compared to the model group (P<0.01). However, the alveolar bone loss was significantly less (P<0.01 in the systemic treatment group compared to the local treatment group. Monocyte infiltration and resorption lacunae with osteoclasts were significantly less in the both treatment groups compared to the model group (P<0.01). The osteoclasts failed to form a ruffled border in the systemic treatment group.

CONCLUSION

Topical treatment significantly reduces gingivitis while systemic treatment is beneficial in terms of inhibiting alveolar bone loss.

Injectable Polysaccharide Microcapsules for Prolonged Release of Minocycline for the Treatment of Periodontitis

Injectable polysaccharide microcapsules holding minocycline were fabricated from alginate and chitosan for the treatment of periodontitis. The microcapsules were examined for the release and degradation of minocycline, as well as antimicrobial activity. The microcapsules were biodegradable and released minocycline between 10 and 1000 microg ml(-1), which was higher than the usual therapeutic concentration (1-5 microg ml(-1)), for up to 7 days. These microcapsules showed a statistically significant suppression of pathogenic bacteria, such as Prevotella intermedia causing periodontitis. The microcapsules are thus potentially useful for drug delivery for the treatment of periodontitis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.