Zero-order delivery with periodontal placement of tetracycline-loaded ethylene vinyl acetate fibers

Antibacterial activities of phytochemicals against Porphyromonas gingivalis with and without experimental fluoride varnish for periodontal disease prevention

We aimed to evaluate the antibacterial activity of phytochemicals with or without an experimental fluoride varnish against Porphyromonas gingivalis. Five phytochemicals, chrysophanol (CHR), emodin (EMO), anthrarufin (ANT), bavachalcone (BCC), and isobavachromene (IBC), were tested using agar diffusion, minimal inhibition concentration (MIC), and minimum bacterial concentration (MBC) assays. We also assessed the cell viability and cytotoxicity of phytochemicals. All phytochemicals showed clear inhibition zones in the agar diffusion test. The inhibition zones of all phytochemical-containing fluoride varnishes were similar to or larger than that of the positive control, excluding that of 1 mM EMO. With or without the fluoride varnish, BCC exhibited the lowest MIC and MBC levels. Cell viability was high in the presence of all phytochemicals except 200 μM EMO. In conclusion, BCC was most effective as a phytochemical alone, while all phytochemical-containing fluoride varnishes inhibited P. gingivalis growth without cytotoxicity.

Current Drug Delivery Strategies for Buccal Cavity Ailments using Mouth Dissolving Wafer Technology: A Comprehensive Review on the Present State of the Art

BACKGROUND

Mouth-dissolving wafer is polymer-based matrice that incorporates various pharmaceutical agents for oral drug delivery. This polymeric wafer is ingenious in the way that it needs not be administered with water, like in conventional tablet dosage form. It has better compliance among the pediatric and geriatric groups owing to its ease of administration.

OBJECTIVE

The polymeric wafer dissolves quickly in the oral cavity and is highly effective for a targeted local effect in buccal-specific ailments. It is a safe, effective, and versatile drug delivery carrier for a range of drugs used to treat a plethora of oral cavity-specific ailments that inflict common people, like thrush, canker sores, periodontal disease, benign oral cavity tumors, buccal neoplasm, and malignancies. This review paper focuses thoroughly on the present state of the art in mouth-dissolving wafer technology for buccal drug delivery and targeting. Moreover, we have also addressed present-time limitations associated with wafer technology to aid researchers in future developments in the arena of buccal drug delivery.

CONCLUSION

This dynamic novel formulation has tremendous future implications for designing drug delivery systems to target pernicious ailments and diseases specific to the buccal mucosa. In a nutshell, this review paper aims to summarize the present state of the art in buccal targeted drug delivery.

Supra and subgingival application of antiseptics or antibiotics during periodontal therapy

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

Local Delivery and Controlled Release Drugs Systems: A New Approach for the Clinical Treatment of Periodontitis Therapy

Periodontitis is an inflammatory disease of the gums characterized by the degeneration of periodontal ligaments, the formation of periodontal pockets, and the resorption of the alveolar bone, which results in the destruction of the teeth's supporting structure. Periodontitis is caused by the growth of diverse microflora (particularly anaerobes) in the pockets, releasing toxins and enzymes and stimulating the immune system. Various approaches, both local and systemic, have been used to treat periodontitis effectively. Successful treatment depends on reducing bacterial biofilm, bleeding on probing (BOP), and reducing or eliminating pockets. Currently, the use of local drug delivery systems (LDDSs) as an adjunctive therapy to scaling and root planing (SRP) in periodontitis is a promising strategy, resulting in greater efficacy and fewer adverse effects by controlling drug release. Selecting an appropriate bioactive agent and route of administration is the cornerstone of a successful periodontitis treatment plan. In this context, this review focuses on applications of LDDSs with varying properties in treating periodontitis with or without systemic diseases to identify current challenges and future research directions.

Effects of Hypochlorous Acid and Hydrogen Peroxide Treatment on Bacterial Disinfection Treatments in Implantoplasty Procedures

One of the main problems in oral implantology today is peri-implantitis, which affects almost 20% of dental implants placed in patients. One of the most commonly used techniques to eliminate bacterial biofilm is the implantoplasty, that consists of the mechanical modification of the implant surface topography followed by treatments with chemical reagents for decontamination. In this study, the main aim is to evaluate the use of two different chemical treatments based on hypochlorous acid (HClO) and hydrogen peroxide (H₂O₂). For this purpose, 75 titanium grade 3 discs were treated with implantoplasty according to established protocols. Twenty-five discs were used as controls, 25 were treated with concentrated HClO and 25 were treated with concentrated HClO followed by treatment with 6% H₂O₂. The roughness of the discs was determined using the interferometric process. Cytotoxicity with SaOs-2 osteoblastic cells was quantified at 24 and 72 h, whereas bacteria proliferation using S. gordonii and S. oralis bacteria was quantified at 5 s and 1 min of treatment. The results showed an increase in the roughness values, the control discs had an Ra of 0.33 μm and those treated with HClO and H₂O₂ reached 0.68 μm. Cytotoxicity was present at 72 h, together with a significant proliferation of bacteria. These biological and microbiological results can be attributed to the roughness produced by the chemical agents that triggered bacterial adsorption while inhibiting osteoblast adhesion. The results indicate that even if this treatment can decontaminate the titanium surface after implantation, the produced topography will generate an environment that will not favor long-term performance.

Drug-Coated Floss to Treat Gum Diseases: In Vitro and In Vivo Characterization

Treatment of gum disease often requires antibiotic treatment. In this study, our objective was to advance the practicality of drug-coated floss as an intra gum pocket drug delivery system. The initial design of this delivery system has been previously reported by us. Here, we advance the concept further through in vitro and in vivo evaluation. A floss piece was dip coated in the middle section with model molecules leaving free ends for holding. Porcine gum tissues were used ex vivo and in vivo to evaluate the coated floss, including effect of coating thickness on delivery efficiency, ability to deliver more than one type of molecule (one hydrophilic and one hydrophobic), mechanical properties using a scratch test, and finally retention of delivered material in vivo in the porcine model. After reaching a certain coating thickness, the delivery efficiency of the coated floss decreased, indicating the presence of an optimal coating thickness. Hydrophobic and hydrophilic molecules were successfully coated and delivered with high efficiency into gum pockets. The scratch test indicated that the coatings were resilient. Lastly, the in vivo analysis showed that the drug coating was delivered into the porcine gum pocket with about 65% efficiency, and the coatings could maintain extended residency within the gum pocket despite the native adverse environment of the oral cavity. Overall, this data shows that drug-coated floss can act as a drug delivery vehicle and has potential to provide a minimally invasive and practical method for the delivery of drugs into the gum pockets.

Increased local concentrations of growth factors from leucocyte- and platelet-rich fibrin do not translate into improved alveolar ridge preservation: an intraindividual mechanistic randomized controlled trial

AIMS

Leucocyte- and platelet-rich fibrin (L-PRF) has been tested for enhancing alveolar ridge preservation (ARP), but little is known about the local release profile of growth factors (GF) and the clinical equipoise related to its efficacy remains. This study compared the patterns of GF release, early soft tissue healing and alveolar ridge resorption following unassisted healing and L-PRF application in non-molar extraction sockets.

MATERIALS AND METHODS

Atraumatic tooth extraction of two hopeless teeth per patient was followed by unassisted healing or L-PRF placement to fill the socket in 18 systemically healthy, nonsmoking subjects. This intraindividual trial was powered to assess changes in horizontal alveolar ridge dimensions 1 mm below the crest of alveolar bone. GF concentrations in wound fluid were assessed with a multiplex assay at 6, 24, 72 and 168 hours. Early healing was evaluated with the wound-healing index and changes in soft tissue volumes on serial digital scans. Hard tissue changes were measured on superimposed CBCT images after 5 months of healing.

RESULTS

L-PRF resulted in higher GF concentrations in WF as compared to the control, but no differences in release patterns or time of peak were observed. No intergroup differences in early healing parameters were observed. Alveolar bone resorption was observed in both groups. No significant intergroup differences were observed in hard tissue healing 1, 3 or 5 mm apical to the original bone crest, or in ability to digitally plan a prosthetically guided implant with or without bone augmentation.

CONCLUSIONS

L-PRF increased the GF concentrations in wound fluid of extraction sockets without shifting the pattern observed in unassisted healing, while the increased delivery did not translate into clinical benefits in early wound healing or ARP. The current findings question the assumption that increased local concentrations of GF by L-PRF translate into improved clinical outcomes. Additional definitive studies are needed to establish the benefits of L-PRF in ARP. (clinicaltrials.gov NCT03985033).

Local drug delivery systems as therapeutic strategies against periodontitis: A systematic review

Periodontitis is a chronic inflammation of the soft tissue surrounding and supporting the teeth, which causes periodontal structural damage, alveolar bone resorption, and even tooth loss. Its prevalence is very high, with nearly 60% of the global population affected. Hence, periodontitis is an important public health concern, and the development of effective healing treatments for oral diseases is a major target of the health sciences. Currently, the application of local drug delivery systems (LDDS) as an adjunctive therapy to scaling and root planning (SRP) in periodontitis is a promising strategy, giving higher efficacy and fewer side effects by controlling drug release. The cornerstone of successful periodontitis therapy is to select an appropriate bioactive agent and route of administration. In this context, this review highlights applications of LDDS with different properties in the treatment of periodontitis with or without systemic diseases, in order to reveal existing challenges and future research directions.

Minocycline-loaded PLGA electrospun membrane prevents alveolar bone loss in experimental peridontitis

Minocycline (MINO) is a tetracycline antibiotic effective against most of the bacteria microorganisms related to periodontal disease. Additionally, MINO promotes bone in vitro and in vivo. The objective of the present study was to establish the protocol for the preparation of MINO-loaded poly (lactic-co-glycolic acid) (MINO-PLGA) electrospun membranes and to evaluate their effect on osteogenesis in vitro and in a rat model of periodontitis. The characterization of MINO-PLGA electrospun membranes was assessed by scanning electron microscopy, laser scanning confocal microscopy, and contact angle measurement. The drug release study showed a sustained diffusion of MINO from electrospun membranes over a period of 40 d. The MINO-PLGA membranes containing 2% of the drug exhibited better support of osteoblast proliferation and adhesion and was subsequently used in vivo in an experimental periodontitis model. Its therapeutic potential was evaluated by the measurement of alveolar bone loss (ABL), bone volume analysis, histological analysis, and immunohistochemistry. MINO-PLGA membrane increased alveolar crest height in the periodontitis model, inhibited the expression of the ligand of the receptor activator for nuclear factor-κB (RANKL), and promoted the expression of its inhibitor, osteoprotegerin. The study demonstrated that MINO-PLGA electrospun membranes may be applied to stimulate bone regeneration in periodontitis.

Adjunctive local treatments for patients with residual pockets during supportive periodontal care: A systematic review and network meta-analysis

AIM

This systematic review and network meta-analysis aimed to evaluate the efficacy of adjunctive locally delivered antimicrobials, compared to subgingival instrumentation alone or plus a placebo, on changes in probing pocket depth (PPD) and clinical attachment level (CAL), in patients with residual pockets during supportive periodontal care.

MATERIALS AND METHODS

Literature search was performed with electronic databases and by hand until 31 May 2020. Primary outcome was the changes in PPD. The treatment effects between groups were estimated with weighted mean differences (WMD) with 95% confidence intervals (CI) and prediction intervals (PI) by using random-effects network meta-analysis.

RESULTS

Twenty-two studies were included. Significantly greater PPD reduction was achieved in chlorhexidine chip group (WMD: 0.65 mm, 95% CI: 0.21-1.10) and tetracycline fibre group (WMD: 0.64 mm, 95% CI: 0.20-1.08) over 6-month follow-up. Other adjunctive antimicrobial agents achieved non-significant improvements compared to scaling and root planing alone. All differences between adjunctive therapies were statistically non-significant. Similar findings were observed for CAL gain.

CONCLUSION

Adjunctive local antimicrobial agents achieved small additional PPD reduction and CAL gain in residual pockets for a follow-up of up to 6 months. Tetracycline fibre and chlorhexidine chip achieved better results than other antimicrobials.

Sustained-release delivery of antimicrobial drugs for the treatment of periodontal diseases: Fantasy or already reality?

Periodontal diseases are prevalent in humans. Conventional means of combating these diseases involve basic oral hygiene, mostly toothbrushing, use of mouthwashes, and flossing. Supplementary means of treatment, either clinical or pharmaceutical, are often necessary. The use of sustained-release delivery systems, applied locally to the periodontal pocket, seems to be one feasible approach: local sustained-release delivery of antibacterial agents to treat periodontal diseases is conceivable. The use of local (intrapocket) sustained-release delivery systems has numerous clinical, pharmacologic, and toxicologic advantages over conventional treatments for periodontal diseases. Sustained-release technology has been proven to be effective over the last few decades. Films, gels, and fibers are the three main classical intrapocket pharmaceutical delivery systems. Research today is more focused on improving drug delivery, and less on introducing new drugs. New approaches, eg, those making use of nanotechnology, are emerging for local drug-delivery systems. The local sustained-release delivery system concept is innovative and a few products are already commercially available.

In Vitro Evaluation of Antimicrobial Activity of Minocycline Formulations for Topical Application in Periodontal Therapy

Periodontal therapy using antimicrobials that are topically applied requires slow or controlled release devices. The in vitro antimicrobial activity of biodegradable polymer formulations that contain a new minocycline lipid complex (P-MLC) was evaluated. The new P-MLC formulations that contained 11.5% minocycline were compared with pure minocycline or an existing commercial formulation, which included determination of minimal inhibitory concentration (MIC) values against two oral bacteria and activity on six-species periodontal biofilm. Moreover, the flow of gingival crevicular fluid (GCF) was modeled up to 42 d and the obtained eluates were tested both for MIC values and inhibiting biofilm formation. In general, MICs of the P-MLC formulations were slightly increased as compared with pure minocycline. Biofilm formation was clearly inhibited by all tested formulations containing minocycline with no clear difference between them. In 3.5 d old biofilms, all formulations with 250 µg/mL minocycline decreased bacterial counts by 3 log10 and metabolic activity with no difference to pure antimicrobials. Eluates of experimental formulations showed superiority in antimicrobial activity. Eluates of one experimental formulation (P₅₀₃-MLC) still inhibited biofilm formation at 28 d, with a reduction by 1.87 log10 colony forming units (CFU) vs. the untreated control. The new experimental formulations can easily be instilled in periodontal pockets and represent alternatives in local antimicrobials, and thus warrant further testing.

Commercial Local Pharmacotherapeutics and Adjunctive Agents for Nonsurgical Treatment of Periodontitis: A Contemporary Review of Clinical Efficacies and Challenges

Periodontal infections tend to be site-specific, mostly confined to the periodontal pocket. With the surge of antibiotic-resistant bacteria, the trend is shifting towards other therapeutic modalities, especially locally delivered approaches that include other pharmacotherapeutic drugs and medical devices. This narrative review aimed to provide insights into the clinical efficacy of local drug delivery and adjunctive agents used in nonsurgical management of periodontitis. Electronic (PubMed/MEDLINE, CENTRAL, and EMBASE) and bibliographic searches of past systematic reviews were carried out to identify previous publications on the topic. Only relevant literature and randomized controlled trials published in English were selected. In addition, a literature review was developed based on the selected articles. Experimental drugs or agents were excluded. This review highlights the clinically proven and commercially available therapeutic agents related to the management of periodontal disease with comparisons of their clinical efficacies and challenges. A vast array of commercial local pharmacotherapeutic agents had been clinically tested, but the methodologies and clinical results varied within and between each agent used, causing difficulty in drawing conclusions and providing support to the superiority of one agent over another. Considering the benefit-cost ratio with the modest clinical results, the long-term usefulness of these agents remains debatable.

Local Drug Delivery Based Treatment Approaches for Effective Management of Periodontitis

Background:

Periodontal disease is an immuno-inflammatory condition of tissues that surround and hold the teeth. It is the disease which succeeds in all races, groups and both genders. Almost 10 to15% of the global population gets suffered from severe periodontitis as per WHO reports. Periodontal disease may likely cause other systemic diseases such as cardiovascular disease and pre-term low birth weight infants. Mechanical removal of plaques and calculus deposits from supra and subgingival environment is the backbone of periodontal treatment till date whereas complete elimination of these deleterious agents is quite unrealistic as the pocket depth increases.

Recent Approaches:

Recently controlled local drug delivery application is more encouraging in comparison to systemic approach as it mainly targets to enhance the therapeutic efficacy by maintaining site-specificity, avoiding first pass metabolism, reduction in gastrointestinal (GI) side effects and decreasing the dose. Several drugs such as antiseptics and antibiotics alongwith various carriers are being formulated as local drug delivery systems for effective management of the disease. Various local delivery systems reported are fibers, films, strips, compacts, injectables, microparticles, vesicular carriers, gels and nanoparticles. These local carriers provide effective prolonged treatment at the site of infection at reduced doses. This review enlightens detailed pathophysiology and various phases of periodontitis, challenges in treatment of disease and various antimicrobial agents (along with their marketed formulations) used. The main emphasis of the review is to cover all carrier systems developed so far for local delivery application in the effective management of periodontitis, as a patient compliant drug therapy.

The depth of the implant mucosal tunnel modifies the development and resolution of experimental peri-implant mucositis: A case-control study

Background

Resolution and prevention of peri‐implant mucositis are a key in preventing peri‐implantitis. This case–control study aims to assess the modifying effect of a deep mucosal tunnel (DMT) on the induction and resolution phases of experimental peri‐implant mucositis.

Methods

Nineteen subjects with a tissue level implant were assigned to cases (DMT, depth ≥3 mm) or controls (shallow mucosal tunnel ≤1 mm, SMT). Subjects underwent a standard experimental peri‐implant mucositis protocol characterized by an oral hygiene optimization phase, a 3‐week induction phase using an acrylic stent to prevent self‐performed oral hygiene at the experimental implant, and a 3 + 2 weeks resolution phase. Modified plaque (mPI), gingival index (mGI) and peri‐implant sulcus fluid IL‐1β concentrations were measured over time. Differences between DMT and SMT were assessed with the Mann–Whitney test.

Results

Modified plaque index and mGI increased in parallel during the induction phase. After resumption of oral hygiene practice, mPI and mGI resolved towards baseline values in the SMT group. In DMT, mPI and mGI values diverged: plaque resolved but resolution of inflammation was delayed and of smaller magnitude during the first 3 weeks after resumption of oral hygiene. IL‐1β concentrations were significantly higher in DMT at 21 days (end of induction) and during the resolution phase corroborating the clinical findings. Removal of the crown and submucosal professional cleaning were needed to revert mGI to baseline values in DMT implants.

Conclusions

The depth of the mucosal tunnel modifies the resolution of experimental peri‐implant mucositis at transmucosal implants. This observation raises important questions on the effectiveness of self‐performed oral hygiene in cases where implants are placed deeper and the ability to resolve mucositis and effectively prevent peri‐implantitis in such situations.

Sustained Release of Minocycline From Minocycline-Calcium-Dextran Sulfate Complex Microparticles for Periodontitis Treatment

It is important to address the periodontitis-associated bacteria in the residual subgingival plaque after scaling and root planing to successfully treat periodontitis. In this study, we explored the possibility of exploiting the ion pairing/complexation of minocycline, Ca²⁺, and sulfate/sulfonate-bearing biopolymers to develop an intrapocket delivery system of minocycline as an adjunct to scaling and root planing. Minocycline-calcium-dextran sulfate complex microparticles were synthesized from minocycline, CaCl₂, and dextran sulfate. They were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An in vitro release study was conducted to evaluate the release kinetics of minocycline from these microparticles. Agar disk diffusion assays and biofilm-grown bacteria assays were used to assess antibacterial capability. High loading efficiency (96.98% ± 0.12%) and high loading content (44.69% ± 0.03%) for minocycline were observed for these complex microparticles. Mino-Ca-DS microparticles achieved sustained release of minocycline for at least 9 days at pH 7.4 and 18 days at pH 6.4 in phosphate-buffered saline, respectively. They also demonstrated potent antimicrobial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans in agar disk diffusion and biofilm assays. These results suggested that the ion pairing/complexation of minocycline, Ca²⁺, and sulfonate/sulfate-bearing biopolymers can be exploited to develop complex microparticles as local delivery systems for periodontitis treatment.

IPNs from Cyclodextrin:Chitosan Antioxidants: Bonding, Bio-Adhesion, Antioxidant Capacity and Drug Release

IPNs are unique “alloys” of cross-linked polymers in which at least one network is synthesized and/or cross-linked in the presence of the other. IPNs are also known as entanglements of polymer networks that are ideally held together only by permanent topological interactions. The objectives of this study are to evaluate novel chitosan-based functional drug delivery systems that can be successfully incorporated into “dual action bioactive tooth restorative materials”. These materials should be capable of inducing an improved wound healing prototype. The novel hydrogels will be investigated with respect to the antioxidant capacity of conventional antioxidants, such as resveratrol, β-carotene and propolis, as a designer drug delivery system, with the use of SEM imaging for the characterization of the surfaces, bio-adhesive property, antioxidant capacity, free radical defence, antioxidant, active ingredient stability and reactive features of novel materials. The additional benefit of the site-specific “functional restorative material” for use in dressings to deliver antibiotics to wound sites can provide tissue compatibility and reduced interference with wound healing. The materials were tested using an effective in vitro free radical generation model as functional additive prototypes for further development of “dual function restorative wound healing materials”. We quantified the effects of functional designer biomaterials on the dentin bond strength of a composite and evaluated the bio-adhesive capacity of the materials in the two separate “in vitro” systems. The added benefits of the chitosan/vitamin C/cyclodextrin (CD) host:guest complex-treated hydrogels involved a positive influence on the tetracycline release, increased dentin bond strength, as well as a demonstrated in vitro “built-in” free radical defence mechanism and, therefore, acting as a “proof of concept” for functional multi-dimensional restorative wound healing materials with a built-in free radical defence mechanism. Based on our results, we can conclude that the CD:chitosan-antioxidant-containing hydrogels are a suitable carrier for tetracycline to be slow-released. Within the limitations of the study design, chitosan-based hydrogels are suitable materials for functional restorative and wound healing applications in vitro. Cytotoxicity data are currently being evaluated in our laboratory.

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.

Treatment modalities and evaluation models for periodontitis

Periodontitis is the most common localized dental inflammatory disease related with several pathological conditions like inflammation of gums (gingivitis), degeneration of periodontal ligament, dental cementum and alveolar bone loss. In this perspective, the various preventive and treatment modalities, including oral hygiene, gingival irrigations, mechanical instrumentation, full mouth disinfection, host modulation and antimicrobial therapy, which are used either as adjunctive treatments or as stand-alone therapies in the non-surgical management of periodontal infections, have been discussed. Intra-pocket, sustained release systems have emerged as a novel paradigm for the future research. In this article, special consideration is given to different locally delivered anti-microbial and anti inflammatory medications which are either commercially available or are currently under consideration for Food and Drug Administration (FDA) approval. The various in vitro dissolution models and microbiological strain investigated to impersonate the infected and inflamed periodontal cavity and to predict the in vivo performance of treatment modalities have also been thrashed out. Animal models that have been employed to explore the pathology at the different stages of periodontitis and to evaluate its treatment modalities are enlightened in this proposed review.

Control of periodontal infections: a randomized controlled trial I. The primary outcome attachment gain and pocket depth reduction at treated sites

OBJECTIVE

To compare the treatment outcome of scaling and root planing (SRP) in combination with systemic antibiotics, local antibiotic therapy and/or periodontal surgery.

MATERIAL AND METHODS

One hundred and eighty-seven patients were assigned to eight groups treated by SRP plus none, one, two or three adjunctive treatments and monitored for 24 months in a randomized controlled clinical trial using a 2 × 2 × 2 factorial design. Systemic amoxicillin + metronidazole (SMA), local tetracycline delivery (LTC) and periodontal surgery (SURG) were evaluated as adjuncts. Changes in clinical attachment level (CAL) and probing pocket depth (PPD) were statistically evaluated by ancova of main effects.

RESULTS

Effects of adjunctive therapy to SRP were minimal at 3 months. Between 3 and 6 months PPD reduction occurred particularly in patients receiving periodontal surgery. After 6 months, both CAL gain and PPD reduction reached a plateau that was maintained at 24 months in all groups. The 24-month CAL gain was improved by SMA (0.50 mm) while PPD was reduced by SMA (0.51 mm) and SURG (0.36 mm). Smoking reduced CAL gain and PPD reduction.

CONCLUSION

Patients receiving adjunctive therapies generally exhibited improved CAL gain and/or PPD reduction when compared with the outcome of SRP alone. Only additive, not synergistic effects of the various adjunctive therapies were observed.

Intraperiodontal pocket: An ideal route for local antimicrobial drug delivery

Periodontal pockets act as a natural reservoir filled with gingival crevicular fluid for the controlled release delivery of antimicrobials directly. This article reflects the present status of nonsurgical controlled local intrapocket delivery of antimicrobials in the treatment of periodontitis. These sites have specialty in terms of anatomy, permeability, and their ability to retain a delivery system for a desired length of time. A number of antimicrobial products and the composition of the delivery systems, its use, clinical results, and their release are summarized. The goal in using an intrapocket device for the delivery of an antimicrobial agent is the achievement and maintenance of therapeutic drug concentration for the desired period of time. Novel controlled drug delivery system are capable of improving patient compliance as well as therapeutic efficacy with precise control of the rate by which a particular drug dosage is released from a delivery system without the need for frequent administration. These are considered superior drug delivery system because of low cost, greater stability, non-toxicity, biocompatibility, non-immunogenicity, and are biodegradable in nature. This review also focus on the importance and ideal features of periodontal pockets as a drug delivery platform for designing a suitable dosage form along with its potential advantage and limitations. The microbes in the periodontal pocket could destroy periodontal tissues, and a complete knowledge of these as well as an ideal treatment strategy could be helpful in treating this disease.

The Application of Microencapsulation Techniques in the Treatment of Endodontic and Periodontal Diseases

In the treatment of intracanal and periodontal infections, the local application of antibiotics and other therapeutic agents in the root canal or in periodontal pockets may be a promising approach to achieve sustained drug release, high antimicrobial activity and low systemic side effects. Microparticles made from biodegradable polymers have been reported to be an effective means of delivering antibacterial drugs in endodontic and periodontal therapy. The aim of this review article is to assess recent therapeutic strategies in which biocompatible microparticles are used for effective management of periodontal and endodontic diseases. In vitro and in vivo studies that have investigated the biocompatibility or efficacy of certain microparticle formulations and devices are presented. Future directions in the application of microencapsulation techniques in endodontic and periodontal therapies are discussed.

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.

Recent approaches for the treatment of periodontitis

Periodontal disease is a localised inflammatory response caused by the infection of a periodontal pocket arising from the accumulation of subgingival plaque. Periodontal disease has been considered as a possible risk factor for other systemic diseases such as cardiovascular diseases and pre-term low birth weight infants. Advances in understanding the aetiology, epidemiology and microbiology of periodontal pocket flora have revolutionised the therapeutic strategies for the management of periodontal disease progression. This review summarises the recent developments in the field of intra-pocket drug delivery systems and identifies areas where further research may lead to a clinically effective intra-pocket delivery system.

Controlled release of an antibiotic, gentamicin sulphate, from gravity spun polycaprolactone fibers

The antibiotic, gentamicin sulphate (GS), was incorporated in gravity-spun polycaprolactone (PCL) fibers by spinning from particulate suspensions of the drug in PCL solution to produce a controlled delivery system. The production rate of GS-loaded PCL fibers was confined to the range 1-1.5 m/min and the fiber diameter to 170-220 microm. The kinetics of drug release could be adjusted by varying the GS loading of the fibers and the suspension preparation conditions. Gradual release of approximately 80% of the initial GS content was measured in phosphate buffered saline at 37 degrees C over 50 days from fibers spun from nonhomogenized suspensions, whereas loss of this amount of antibiotic occurred in less than 10 days from fibers spun from homogenized suspensions. Studies of growth inhibition of Stapyhlococcus epidermidis in culture indicated that GS released after 2 weeks from PCL fibers retained antibacterial activity. This behavior recommends further investigation of PCL fibers for local delivery of antibiotics to combat infection associated with periodontal disease, musculoskeletal injuries, and implantation of fiber-based tissue substitutes such as vascular prostheses.

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.

A comparative evaluation of the clinical effects of systemic and local doxycycline in the treatment of chronic periodontitis

In this study, the clinical efficacies of systemic doxycycline (SD) and local doxycycline (LD) in the treatment of chronic periodontitis were compared. Forty-five patients were studied in 3 main groups with 5 treatments: SD alone, SD+scaling-root planing (SD+SRP), LD alone, LD+SRP and SRP alone. Antibiotic-treated patients were given doxycycline treatment alone in 1 quadrant of their upper jaws, and doxycycline+SRP was given in the contralateral quadrant. The areas included at least 4 teeth with > or = 5 mm pockets. Probing depth (PD), clinical attachment level, gingival index, sulcular bleeding index and plaque index values were recorded at baseline and the 7th week. The results were statistically analyzed. All of the clinical parameters were significantly reduced by all treatments (P < or = 0.05). The SD and LD treatments alone provided significant clinical healings. The significant differences among the groups were only in PD at the 7th week. The LD treatment provided significantly higher PD reduction than the SD treatment (P < or = 0.05). No significant difference was found between the SD+SRP and the LD+SRP treatments. There was no significant difference between SD+SRP and SRP alone treatment (P > 0.05). The SD group showed lower PD reduction than SRP group (P < or = 0.05), while no significant difference was found between LD and SRP treatments. The LD alone treatment seemed more effective than SD alone treatment on PD reduction, but no significant difference was found between them when combined with the SRP. LD may be more preferable than SD as an adjunct to mechanical treatment since LD seems more effective than SD on PD reduction and does not have the side effects of SD.

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.

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

BACKGROUNDS/AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Poly(anhydride-ester) fibers: Role of copolymer composition on hydrolytic degradation and mechanical properties

Poly(anhydride-esters), based on carboxyphenoxydecanoate (CPD), are biocompatible polymers that hydrolytically degrade. The mechanical properties of the poly(anhydride-esters) can be altered by copolymerization with para-carboxyphenoxyhexane (pCPH). Mechanical properties of three CPD:pCPH compositions (30:70, 40:60, and 50:50) are reported as a function of hydrolytic degradation. The mechanical characteristics evaluated were tensile modulus at 1% strain (E(1%)), tensile strength (sigma(B)), ultimate elongation (epsilon(B)), and toughness (E(r)). The 30:70 CPD:pCPH fibers maintained higher values for tensile modulus at all time points than the two other fiber compositions. In addition, the 30:70 CPD:pCPH fibers maintained lower values for both tensile strength and toughness than the two other fiber compositions. These phenomena resulted from the brittle nature of pCPH, the major component of the 30:70 CPD:pCPH fibers; increasing the pCPH concentration in the polymer lowers both tensile strength and toughness of the polymer by decreasing ductility. With increasing amounts of pCPH, the hydrolytic degradation occurred more slowly, as reflected in the copolymers' improved ability to retain their mechanical properties. Therefore, copolymerization is useful for controlling the mechanical properties of the fibers as well as the polymer degradation rate, which ultimately determines the rate at which physically or chemically encapsulated drugs can be released.

Surface effects and desorption of tetracycline supramolecular complex on bovine dentine

The aim of this in vitro study was to evaluate the antimicrobial activity, the substantivity, and surface effects of the inclusion compound tetracycline: beta-cyclodextrin on bovine roots. The antimicrobial activity was assessed by dentine slabs which had been immersed in the inclusion complex in concentrations 8.0%, 4.0%, 2.0%, 1.0%, 0.5% and 0.25% for 5min compared to a control of tetracycline hydrochloride. Each slab was tested in a broth of overnight culture of Actinobacillus actinomycetemcomitans (Y4-FDC). The inclusion complex significantly inhibited the A. actinomycetemcomitans (p<0.01) verified at concentrations from 1.0% to 8.0%. The substantivity of tetracycline was evaluated by the measure of desorption from the slabs previously immersed in solution samples and removed at 24h intervals. The tetracycline encapsulated in beta-cyclodextrin showed a flow rate near to zero order in comparison to free tetracycline. The surface morphology determined by SEM showed a more homogeneous and integrated layer with the complex compared to the effect of free tetracycline. We concluded that the root surfaces treated with tetracycline: beta-cyclodextrin release lower concentrations of active drug over 5 days at inhibitory concentrations against A. actinomycetemcomitans with enhanced disponibility in comparison to tetracycline.

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.

Release of tetracycline hydrochloride from electrospun poly(ethylene-co-vinylacetate), poly(lactic acid), and a blend

Electrospun fiber mats are explored as drug delivery vehicles using tetracycline hydrochloride as a model drug. The mats were made either from poly(lactic acid) (PLA), poly(ethylene-co-vinyl acetate) (PEVA), or from a 50:50 blend of the two. The fibers were electrospun from chloroform solutions containing a small amount of methanol to solubilize the drug. The release of the tetracycline hydrochloride from these new drug delivery systems was followed by UV-VIS spectroscopy. Release profiles from the electrospun mats were compared to a commercially available drug delivery system, Actisite (Alza Corporation, Palo Alto, CA), as well as to cast films of the various formulations.

The effects of subgingival calculus on the clinical outcomes of locally-delivered controlled-release doxycycline compared to scaling and root planing

BACKGROUND/AIM

The effect of subgingival calculus on the clinical outcomes of the local delivery of antimicrobials is unknown. This study examines the clinical outcomes of treatment with locally delivered controlled-release doxycycline (DH) or scaling and root planing (SRP) in subsets of adult periodontitis patients with known baseline levels of subgingival calculus.

METHODS

The data examined were obtained from 393 patients who participated in 2 multi-center trials. All patients had baseline subgingival calculus levels assessed and were then treated at baseline and month 4 with either DH or SRP. Clinical attachment levels (CAL), pocket depth (PD) and bleeding on probing (BOP) were assessed at baseline and months 1, 2, 4, 5, 6, 8 and 9.

RESULTS

Treatment with either DH or SRP resulted in significant statistical and clinical improvements in CAL, PD and BOP. These clinical outcomes were equivalent regardless of the extent of subgingival calculus present at baseline.

CONCLUSIONS

The results indicate that the primary clinical effects of these therapies are the result of a disruption and reduction of the subgingival plaque and not the effect of the removal of subgingival calculus and contaminated cementum.

Non-surgical periodontal therapy with adjunctive topical doxycycline: a double-blind randomized controlled multicenter study

AIM

Evaluation of the clinical effect of topical application of doxycycline adjunctive to non-surgical periodontal therapy.

METHODS

A total of 111 patients suffering from untreated or recurrent moderate to severe periodontitis at 3 different centers (Heidelberg, Frankfurt, Nijmegen) were treated in this double-blind split-mouth study. In each patient, 3 different treatment modalities were assigned randomly to 3 test teeth: scaling and root planing alone (SRP), SRP with subgingival vehicle control (VEH), and SRP with subgingival application of a newly developed biodegradable 15% doxycycline gel (DOXI). At baseline, clinical parameters were measured at all single rooted teeth using a reference splint: PlI, PPD, relative attachment level (RAL-V), GI. 3 strata were generated according to baseline PPD: (i) 5-6 mm, (ii) 7-8 mm, (iii) > or =9 mm. Not more than 50% active smokers were allowed to each stratum. 3 and 6 months after therapy re-examination was performed by examiners blinded to baseline data and test sites. The statistical comparison of RAL-V gain and PPD reduction between the treatments was based on a repeated measures ANOVA with correction according to Huynh & Feldt. The comparison of SRP versus DOXI was considered as the main study question.

RESULTS

110 patients finished the 3 months and 108 the 6 months examination. The study did not show adverse effects of VEH or DOXI except for one singular inflammation that occurred 2 months after application of the doxycycline gel. DOXI provided statistically significantly more favorable PPD reduction (SRP: -2.4+/-1.4 mm, VEH: -2.7+/-1.6 mm, DOXI: -3.1+/-1.2 mm; SRP versus DOXI p=0.0001, VEH versus DOXI p=0.0066) and RAL-V gain (SRP: 1.6+/-1.9 mm, VEH: 1.6+/-2.2 mm, DOXI: 2.0+/-1.7 mm; SRP versus DOXI p=0.027, VEH versus DOXI p=0.038) than SRP and VEH after 6 months.

CONCLUSIONS

Adjunctive topical subgingival application of a biodegradable 15% doxycycline gel was safe and provided more favorable RAL-V gain and PPD reduction than SRP alone and VEH. Thus, by use of topical doxycycline the threshold for surgical periodontal therapy might be moved toward deeper pockets.

Controlled local delivery of tetracycline with polymer strips in the treatment of periodontitis

BACKGROUND

Several antibacterial agents have been studied as a means to produce bactericidal or bacteriostatic activity as an adjunct to mechanical treatment of periodontal disease. The primary purpose of this study was to evaluate the efficacy of tetracycline strips administered singly or in multiples in conjunction with root planing, versus root planing alone, or to an untreated control. Secondary purposes were to compare gingival crevicular fluid (GCF) volume and GCF concentrations of tetracycline in pockets treated with strips; to evaluate strip insertion time; and to compare ease of placement for single or multiple strips.

METHODS

Using a 4-quadrant design, 4 test teeth in 24 patients were treated with either root planing and single strip application; root planing and multiple strip application; root planing alone; or an untreated control.

RESULTS

Single and multiple strip placement resulted in a significant reduction in probing depth (P = 0.033) compared to root planing and untreated groups. The multiple strip group significantly decreased bleeding on probing (P = 0.05) compared to all other treatment groups. There was no treatment effect on GCF; however, there was a significant reduction in the GCF volume over time (P = 0.001). The time required for placement was, on average, 1.9 minutes for single strips and 3.25 minutes for multiple strips.

CONCLUSIONS

Our data suggest that multiple strips are superior to a single strip in reducing bleeding on probing, and that local delivery of tetracycline is superior to root planing alone in reducing probing depth.

Therapeutic applications of viscous and injectable poly(ortho esters)

Poly(ortho esters) (POE) are hydrophobic and bioerodible polymers that have been investigated for pharmaceutical use since the early 1970s. Among the four described generations of POE, the third (POE III) and fourth (POE IV) are promising viscous and injectable materials which have been investigated in numerous biomedical applications. POE III has been extensively studied for ophthalmic drug delivery, it presents an excellent biocompatibility and is currently being investigated as a vehicle for sustained drug delivery to treat diseases of the posterior segment of the eye. POE IV is distinguishable by a highly reproducible and controlled synthesis, a higher hydrophobicity, and an excellent biocompatibility. It is currently under development for a variety of applications, such as ocular delivery, periodontal disease treatment and applications in veterinary medicine. This review will also focus on new perspectives for this promising family of polymers, such as guided tissue regeneration, treatment of osteoarthritis, as well as peptide and protein delivery.

Optimization of a novel bioerodible device based on auto-catalyzed poly(ortho esters) for controlled delivery of tetracycline to periodontal pocket

Local delivery of antimicrobial agents in inflamed periodontal pocket has been shown to be effective in reducing periodontopathic microorganisms. This research focuses on developing and characterizing bioerodible formulations based on auto-catalyzed poly(ortho esters) (POExLAy) for modulated release of tetracycline over 2 weeks. POExLAy are a new versatile family of POE-containing lactoyl lactyl dimers in the polymer backbone. By modifying the proportion of lactic acid in the polymer, viscous or solid materials having different degradation rate can be produced. The formulations can be either injected or placed as a solid device directly into the periodontal pocket. Tetracycline-free base incorporated into these materials was released within 10-14 days depending on polymer structure. Increase in lactic acid content in the polymer tended to increase the drug release rate and to reduce the initial lag time. Tetracycline release from such bioerodible delivery system occurs predominantly by surface erosion of the polymeric matrix, leading to kinetics which can be zero order. This periodontal drug delivery system is designed to be used as an adjunct in the treatment of periodontal diseases. Clinical studies are currently in progress.