Antibiotics in the treatment of human periodontal diseases

Moxifloxacin HCl -loaded Cellulose Acetate Butylate In Situ Forming Gel for Periodontitis Treatment

Periodontitis presents significant treatment challenges due to its complexity and potential complications. In response, an in situ forming gel (ISG) loaded with moxifloxacin HCl (Mx) and cellulose acetate butyrate (CAB) was developed for targeted periodontitis therapy. Mx-loaded 10-45% CAB-based ISGs were developed, and their physicochemical properties such as rheology, viscosity, contact angle, gel morphology and gel formation, interface interaction were investigated. Moreover, the formulation performance studies including drug release and kinetics, in vitro degradation, and antimicrobial activities were also evaluated. The Mx-loaded ISGs containing 25-45% CAB demonstrated rapid matrix formation in both macroscopic and microscopic examinations and presented plastic deformation matrix. Tracking with sodium fluorescein and Nile red fluorescence probes indicated delayed solvent movement owing to CAB matrix formation. Adequate CAB content sustained Mx release for one week, following Peppas-Sahlin model and indicating a predominantly Fickian diffusion mechanism. Higher CAB content likely contributed to a denser matrix structure, leading to a slower in vitro degradation rate. Synchrotron radiation X-ray tomographic and SEM imaging provided insights into the CAB matrix structure and porous network formation. These ISG formulations effectively inhibited Staphylococcus aureus, Escherichia coli, Candida albicans, and Porphyromonas gingivalis. The Mx-loaded 40% CAB-based ISG shows promise as a dosage form for treating periodontitis. Further clinical trials are necessary to ensure the safety of this new ISG formulation, despite existing safety data for other medicinal uses of CAB. HIGHLIGHTS: Moxifloxacin HCl-loaded 10-45% cellulose acetate butyrate (CAB)-based in situ forming gels (ISG) were developed. They were evaluated for physicochemical properties, drug release, in vitro degradation, and antimicrobial activities. ISGs with 25-45% CAB showed swift matrix formation and plastic deformation Adequate CAB content sustained Mx release with Fickian diffusion mechanism They promise for periodontitis treatment because of effective inhibition of related pathogens.

Impact of local drug delivery and natural agents as new target strategies against periodontitis: new challenges for personalized therapeutic approach

Periodontitis is a persistent inflammation of the soft tissue around the teeth that affects 60% of the population in the globe. The self-maintenance of the inflammatory process can cause periodontal damage from the alveolar bone resorption to tooth loss in order to contrast the effects of periodontitis, the main therapy used is scaling and root planing (SRP). At the same time, studying the physiopathology of periodontitis has shown the possibility of using a local drug delivery system as an adjunctive therapy. Using local drug delivery devices in conjunction with SRP therapy for periodontitis is a potential tool since it increases drug efficacy and minimizes negative effects by managing drug release. This review emphasized how the use of local drug delivery agents and natural agents could be promising adjuvants for the treatment of periodontitis patients affected or not by cardiovascular disease, diabetes, and other system problems. Moreover, the review evidences the current issues and new ideas that can inspire potential later study for both basic research and clinical practice for a tailored approach.

Levofloxacin HCl-Loaded Eudragit L-Based Solvent Exchange-Induced In Situ Forming Gel Using Monopropylene Glycol as a Solvent for Periodontitis Treatment

Solvent exchange-induced in situ forming gel (ISG) is currently an appealing dosage form for periodontitis treatment via localized injection into the periodontal pocket. This study aims to apply Eudragit L and Eudragit S as matrix components of ISG by using monopropylene glycol as a solvent for loading levofloxacin HCl for periodontitis treatment. The influence of Eudragit concentration was investigated in terms of apparent viscosity, rheological behavior, injectability, gel-forming behavior, and mechanical properties. Eudragit L-based formulation presented less viscosity, was easier to inject, and could form more gel than Eudragit S-based ISG. Levofloxacin HCl-loading diminished the viscosity of Eudragit L-based formulation but did not significantly change the gel formation ability. Higher polymer loading increased viscosity, force-work of injectability, and hardness. SEM photographs and µCT images revealed their scaffold formation, which had a denser topographic structure and less porosity attained owing to higher polymer loading and less in vitro degradation. By tracking with fluorescence dyes, the interface interaction study revealed crucial information such as solvent movement ability and matrix formation of ISG. They prolonged the drug release for 14 days with fickian drug diffusion kinetics and increased the release amount above the MIC against test microbes. The 1% levofloxacin HCl and 15% Eudragit L dissolved in monopropylene glycol (LLM15) was a promising ISG because of its appropriate viscosity (3674.54 ± 188.03 cP) with Newtonian flow, acceptable gel formation and injectability (21.08 ± 1.38 N), hardness (33.81 ± 2.3 N) and prolonged drug release with efficient antimicrobial activities against S. aureus (ATCC 6538, 6532, and 25923), methicillin-resistant S. aureus (MRSA) (S. aureus ATCC 4430), E. coli ATCC 8739, C. albicans ATCC 10231, P. gingivalis ATCC 33277, and A. actinomycetemcomitans ATCC 29522; thus, it is the potential ISG formulation for periodontitis treatment by localized periodontal pocket injection.

Phase Inversion-Based Doxycycline Hyclate-Incorporated Borneol In Situ Gel for Periodontitis Treatment

Borneol has been successfully employed as a gelling agent for in situ forming gel (ISG). While 40% borneol can regulate drug release, there is interest in novel approaches to achieve extended drug release, particularly through the incorporation of hydrophobic substances. Herein, triacetin was selected as a hydrophobic additive solvent for doxycycline hyclate (Dox)-loaded 40% borneol-based ISGs in N-methyl-2-pyrrolidone (NMP) or dimethyl sulfoxide (DMSO), which were subsequently evaluated in terms of their physicochemical properties, gel formation morphology, water sensitivity, drug release, and antimicrobial activities. ISG density and viscosity gradually decreased with the triacetin proportion to a viscosity of <12 cPs and slightly influenced the surface tension (33.14-44.33 mN/m). The low expelled force values (1.59-2.39 N) indicated the convenience of injection. All of the prepared ISGs exhibited favorable wettability and plastic deformation. Higher gel firmness from ISG prepared using NMP as a solvent contributed to the ability of more efficient controlled drug release. High triacetin (25%)-loaded ISG retarded solvent diffusion and gel formation, but diminished gel firmness and water sensitivity. ISG containing 5% triacetin efficiently prolonged Dox release up to 10 days with Fickian diffusion and presented effective antimicrobial activities against periodontitis pathogens such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Therefore, the Dox-loaded 40% borneol-based ISG with 5% triacetin is a potential effective local ISG for periodontitis treatment.

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.

Local delivery therapies as adjuvants to non-surgical periodontal treatment of periodontitis grade C: a systematic review

OBJECTIVES

The aim of this article was to perform a systematic review on the effectiveness of local adjuvant therapies in the treatment of aggressive periodontitis (AgP), now reported as periodontitis grade C.

MATERIALS AND METHODS

The authors selected randomized clinical trials of AgP patients who received local therapy as adjuvants to non-surgical periodontal with a duration of at least 90 days. Seven databases were searched up to January 2020. The gain in clinical attachment level (CAL) and reduction of probing depth (PD) were the outcomes of interest.

RESULTS

Of the 3583 studies found, only five articles were included in the qualitative analysis. Among the substances analyzed, only 1.2 mg of simvastatin gel (SMV) (1.2 mg/0.1 ml), 1% of alendronate gel (ALN) (10 mg/ml), and 25% metronidazole gel (MTZ) (Elyzol^@) showed a significant decrease in the probing depth when compared with their respective control groups. The gain CAL was shown using 1.2 mg SMV gel (1.2 mg/0.1 ml) and 1% ALN gel (10 mg/ml).

CONCLUSION

Although 1.2 mg SMV gel (1.2 mg/0.1 ml), 1% ALN gel (10 mg/ml), and 25% MTZ gel (Elyzol) have shown better results, local therapies adjuvant to SRP the data found were limited. Future clinical studies with appreciable methodological quality should be conducted.

CLINICAL RELEVANCE

Despite some benefits of local delivery therapy, up to now, it has not been possible to prove the efficacy of local therapy as an adjunct to standard treatment of AgP (periodontitis grade C).

Antimicrobial activity of NO-releasing compounds against periodontal pathogens

This study describes the successful synthesis of nitric oxide (NO)-releasing compounds with biodegradable and injectable properties and demonstrates that the kinetics of NO release vary according to the type of NO donor. The antimicrobial activity of NO-releasing compounds against three common periodontal pathogens, i.e., Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Actinomyces israelii, was investigated using a susceptibility assay. Human gingival fibroblasts were treated with NO-releasing compounds at the minimum concentrations required for bacterial growth and cytotoxicity was evaluated using the MTT cell proliferation assay. Our results suggest that NO-releasing compounds can be used topically to treat both gram-negative and gram-positive periodontal pathogens. Comparison of the antimicrobial activity and cytotoxicity assay results between the NO-releasing compounds revealed that an NO donor comprising a macromolecule without surface charge, a lower instantaneous NO concentration, and an adequate supply of NO were associated with a strong bactericidal effect and low cytotoxicity. NO-releasing compounds with these properties may be suitable for treatment of periodontitis.

Thermal Magnetic Field Activated Propolis Release From Liquid Crystalline System Based on Magnetic Nanoparticles

Intra-periodontal pocket drug delivery systems, such as liquid crystalline systems, are widely utilized improving the drug release control and the therapy. Propolis is used in the treatment of periodontal diseases, reducing the inflammatory and infectious conditions. Iron oxide magnetic nanoparticles (MNPs) can improve the treatment when an alternating external magnetic field (AEMF) is applied, increasing the local temperature. The aim of this study was to develop a liquid crystalline system containing MNPs for intra-periodontal pocket propolis release. MNPs were prepared using iron salts and the morphological, size, thermal, x-ray diffraction, magnetometry, and Mössbauer spectroscopy analyses were performed. Cytotoxicity studies using Artemia salina and fibroblasts were also accomplished. The systems were prepared using polyoxyethylene (10) oleyl ether, isopropyl myristate, purified water, and characterized by polarized optical microscopy, rheometry, and in vitro drug release profile using a periodontal pocket simulator apparatus. The antifungal activity of the systems was investigated against Candida spp. using an AEMF. MNPs displayed nanometric size, were monodisperse, and they displayed very low cytotoxicity. Microscopically homogeneous formulations were obtained displaying important physicochemical and biological properties. The system displayed prolonged release of propolis and important in vitro fungicide activity, which was increased when the AEMF was applied, indicating a potentially alternative therapy for the treatment of the periodontal disease.

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).

Effect of controlled-release Periochip™ on clinical and microbiological parameters in patients of chronic periodontitis

BACKGROUND

The aim of the present study was to evaluate and compare the clinical and microbiological effectiveness of Periochip™ as an adjunct to scaling and root planing (SRP) with SRP alone in patients with chronic periodontitis.

MATERIALS AND METHODS

This randomized, split mouth, 3-month clinical and microbiological trial included 30 sites in 15 patients aged 30-50 years diagnosed with chronic periodontitis. In each patient, two bilateral pockets probing 5-7 mm were randomly assigned to test and control groups. The test group received SRP plus Periochip™, whereas the control group received SRP alone. Clinical indices and anaerobic culture analysis was done at baseline, 1 month, and 3 months interval. Total bacterial count and analysis of four major periodontopathogenic bacteria Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), and Fusobacterium nucleatum (Fn) was done.

RESULTS

Significant improvement was obtained in all clinical variables in the test group as compared to the control group over the study period. Total colony counts were significantly reduced in the test group as compared to control over the period of time. At baseline Aa was recovered from 4 test group sites and 5 control group sites, Pg from 15 test group and 14 control group sites, Pi from 5 test group and 2 control group sites, Fn from 7 test and 7 control group sites. At 3 months, Aa was recovered from 1 test group and 4 control group sites, Pg from 4 test group and 8 control group sites, Pi from 1 test group and 1 control group site, Fn from 3 test and 4 control group sites.

CONCLUSION

Periochip™ placement as an adjunct to SRP, showed promising results, when compared to SRP alone. Healthy microflora can be maintained for a longer period of time and delay in the repopulation by periodontopathic microorganisms was observed.

Kinetics of drug release from a biodegradable local drug delivery system and its effect on Porphyromonas gingivalis isolates: An in vitro study

BACKGROUND

Conventional anti-microbial therapy largely consisted of systemic administration of various drugs effective against periodontal pathogens, but fraught with several problems. Based on the concept of local drug delivery a bioresorbable device made of pure fibrillar collagen has been developed. The aim of this study was to study the release of Tetracycline from this collagen fiber (Type I collagen) impregnated with Tetracycline and its antibacterial activity against Porphyromonas gingivalis.

MATERIALS AND METHODS

Porphyromonas gingivalis was isolated from plaque samples of chronic periodontitis patients by using a CO2 incubator. DNA isolation was done followed by polymerase chain reaction (PCR) amplification to confirm the presence of bacteria. The release pattern of Tetracycline was assessed for a period of 10 days in water (group I) and Serum inoculated with Porphyromonas gingivalis (group II).

RESULTS

A significant presence of Tetracycline on all days in Group I and group II and the zone of inhibition was also present in both groups with a steady decline from day 1 to day 10.

CONCLUSION

Since the results were well within the therapeutic concentration of drug required to inhibit the growth of gram -ve bacteria (Porphyromonas gingivalis), this bioresorbable Tetracycline fiber has the potential for clinical application.

Lemongrass essential oil gel as a local drug delivery agent for the treatment of periodontitis

BACKGROUND

It has been long recognized that periodontal diseases are infections of the periodontium, comprising the bacterial etiology, an immune response, and tissue destruction. Treatment strategies aiming primarily at suppressing or eliminating specific periodontal pathogens include adjunct use of local and systemic antibiotics as part of nonsurgical periodontal therapy. Unwanted side effects and resistance of microorganisms toward antibiotics due to their widespread use have modified the general perception about their efficacy. Research in phytosciences has revealed various medicinal plants offering a new choice of optional antimicrobial therapy. Cymbopogon citratus, Stapf. (lemongrass) is a popular medicinal plant. At a concentration ≤2%, lemongrass essential oil inhibits the growth of several kinds of microorganisms including periodontal pathogens, especially the reference strains Actinomyces naeslundii and Porphyromonas gingivalis, which were resistant to tetracycline hydrochloride.

AIMS

To evaluate the efficacy of locally delivered 2% lemongrass essential oil in gel form as an adjunct to scaling and root planing, as compared to scaling and root planing alone for the treatment of chronic periodontitis.

MATERIALS AND METHODS

2% Lemongrass essential oil gel was prepared and placed in moderate to deep periodontal pockets after scaling and root planing.

RESULTS

Statistically significant reduction in probing depth and gingival index and gain in relative attachment level were noted in the experimental group as compared to the control group at 1 and 3 months.

CONCLUSION

Locally delivered 2% lemongrass essential oil gel offers a new choice of safe and effective adjunct to scaling and root planing in periodontal therapy.

Bond strength of self-adhesive resin cements to dentin after antibacterial and chelating solution treatment

OBJECTIVE

The aim of this study was to evaluate the effect of tetracycline HCl, 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) and chlorhexidine digluconate (CHX) on micro push-out (µ-PO) bond strengths of two self-adhesive resin cements on dentin.

MATERIALS AND METHODS

Sixty discs of 1.25 mm thickness (middle dentin) were prepared from human molars perpendicular to the tooth axis. Two standardized occlusal cavities of 2.20 mm occlusal diameter and 1.25 mm cervical diameter were prepared in each disc. The cavities were divided into three groups in accordance with the surface treatment (50 mg/ml tetracycline HCl, 18% HEBP and 2% CHX solutions). Following the treatment of the discs for 5 min, cavities were filled with two different self-adhesive resin cements (Clearfil(™) SA Cement and RelyX(™) Unicem). After light polymerization of cements, µ-PO bond strength tests were performed. Failure modes were examined and dentin morphologic assessments were done. Statistical significance was determined by a multivariate analysis of variance (MANOVA) followed by Tukey's post-hoc test (p < 0.05). Additionally, a paired-samples T-test was used to compare the µ-PO bond strengths of self-adhesive resin cements (p < 0.05).

RESULTS

Paired-samples T-test revealed that there was no significant difference between tested self-adhesive resin cements (p = 0.612). No significant two-factor interaction was observed between Clearfil(™) SA Cement and chemical agents (p = 0.457). Similarly, tetracycline HCl and CHX did not have a significant effect on the bond strength of RelyX(™) Unicem (p > 0.05). However, HEBP significantly decreased the bond strength of RelyX(™) Unicem when compared to the control (p < 0.05). Conclusion. The tetracycline HCl and CHX solutions do not have beneficial effects on µ-PO bond strengths of self-adhesive resin cements. Additionally, the results of this study do not justify the use of self-adhesive resin cements, following HEBP treatment of dentin.

CLINICAL SIGNIFICANCE

The application of topical HEBP solution treatment to dentin could have adverse effects on the µ-PO bond strengths of RelyX(™) Unicem.

Semisolid systems containing propolis for the treatment of periodontal disease: in vitro release kinetics, syringeability, rheological, textural, and mucoadhesive properties

Formulations containing poloxamer 407 (P407), carbopol 934P (C934P), and propolis extract (PE) were designed for the treatment of periodontal disease. Gelation temperature, in vitro drug release, rheology, hardness, compressibility, adhesiveness, mucoadhesion, and syringeability of formulations were determined. Propolis release from formulations was controlled by the phenomenon of relaxation of polymer chains. Formulations exhibited pseudoplastic flow and low degrees of thixotropy or rheopexy. In most samples, increasing the concentration of C934P content significantly increased storage modulus (G'), loss modulus (G''), and dynamic viscosity (eta'), at 5 degrees C, G'' exceeded G'. At 25 and 37 degrees C, eta' of each formulation depended on the oscillatory frequency. Formulations showed thermoresponsive behavior, existing as a liquid at room temperature and gel at 34-37 degrees C. Increasing the C934P content or temperature significantly increased formulation hardness, compressibility, and adhesiveness. The greatest mucoadhesion was noted in the formulation containing 15% P407 (w/w) and 0.25% C934P (w/w). The work of syringeability values of all formulations were similar and very desirable with regard to ease of administration. The data obtained in these formulations indicate a potentially useful role in the treatment of periodontitis and suggest they are worthy of clinical evaluation.

Application of chitosan gel in the treatment of chronic periodontitis

Local administration of antibiotics in periodontal therapy can be provided with an appropriate delivery system. The purpose of this study was to evaluate the clinical effectiveness of chitosan, both as a carrier in gel form and as an active agent in the treatment of chronic periodontitis (CP). The chitosan gel (1% w/w) incorporated with or without 15% metronidazole was prepared and applied adjunctive to scaling and root planing (SRP) in comparison to SRP alone (control group-C), in CP patients. The clinical parameters such as probing depth (PD), clinical attachment level, the amount of gingival recession, plaque index, gingival index, and gingival bleeding time index were recorded at baseline and at weeks 6, 12, and 24. In all groups, significant improvements were observed in clinical parameters between baseline and week 24 (p < 0.05). The reductions in PD values were 1.21 mm for Ch, 1.48 mm for Ch + M, and 0.94 mm for C groups. No complications related to the chitosan were observed in patients throughout the study period. It is suggested that chitosan itself is effective as well as its combination with metronidazole in CP treatment due to its antimicrobial properties.

Development of local injectable dental gel: the influence of certain additives on physicochemical properties of glycerylmonooleate-based formulations

The current research study is based on the design and development of a sol-gel biodegradable controlled-release formulation for use in the treatment of periodontal diseases. Glycerylmonooleate (GMO) was used as a main composition in the gel base. The influence of various additives, e.g., glycerylmonostearate (GMS), methylcellulose (MC), surfactants, and triglycerides, in GMO formulations on rheologic and swelling properties and release characteristics was described. It was demonstrated that the surfactants and triglycerides affected rheologic behavior, whereas GMS and MC influenced both rheologic and swelling properties of the bases. The release study revealed that drug released from the gel bases depended on the square root of time. The kinetics can be explained by the Higuchi's diffusion theory. Some polyols could enhance drug release from the gel. The stability results suggested that the dental gels obtained should be kept in the low temperature range.

Use of antimicrobial agents during supportive periodontal therapy

Individual susceptibility to periodontal breakdown involves an interplay of genes, periodontal pathogens and other modulating factors. Anti-infective treatment, which includes oral hygiene measures, mechanical debridement, pharmacologic intervention and surgery, has been shown to be effective in arresting the progression of periodontal disease. Nevertheless, due to the chronic nature of the disease, susceptible individuals who are not maintained in a supervised recall program subsequent to the active treatment phase, show signs of recurrent destruction. Supportive periodontal therapy (SPT) is an integral part of periodontal treatment for patients with history of periodontitis, and is needed to prevent recurrence of disease in susceptible individuals. To prevent re-infection with periodontal pathogens, SPT includes elimination of dental plaque and bacteria from the oral cavity, thereby preventing the recurrence of pathogens into the gingival area. For individuals at risk of developing periodontitis, SPT should combine self-performed and professional anti-infective therapy, using mechanical and pharmacological means. The existing evidence suggests that the adjunctive use of antimicrobial pharmacologic therapy during SPT may enhance the results of mechanical debridement. The use of antimicrobials varies between patients, and is dependent on risk assessment and longitudinal monitoring of the clinical status of the periodontium.

Systemic antimicrobials in the treatment of chronic periodontal diseases: a dilemma

The use of systemic antimicrobials in the treatment of acute and chronic periodontal diseases must be viewed as a dilemma. On the one hand, the approach is attractive because of the microbial nature of periodontal diseases but, on the other hand, evidence of benefit of these agents is equivocal for the majority of periodontal diseases and antimicrobials have the potential to cause harm. The disadvantages of systemic antimicrobials can be grouped under the headings of allergic reactions, superinfection, toxicity, drug interactions, patient compliance and, perhaps of most widespread importance, bacterial resistance. Mechanical debridement methods, including drainage of pus for acute periodontal abscesses, should be considered the first line treatment for most periodontal diseases. Systemic antimicrobials should be considered as adjuncts to mechanical debridement methods and, in chronic disease, never used alone as they can predispose to abscess formation. Adjunctive systemic antimicrobials may be considered in acute disease where debridement or drainage of pus is difficult, where there is local spread or systemic upset. In chronic periodontal diseases, adjunctive antimicrobials should be considered in early onset or rapidly progressive disease or in advanced chronic adult disease where mechanical therapies have failed or surgery is not a preferred option. Inadequate oral hygiene and tobacco smoking are contraindications to the use of antimicrobials. The value of systemic antimicrobials, where other systemic risk factors co-exist, has still to be established. The role of microbial diagnosis and sensitivity testing for antimicrobial selection at this time must be questioned.

Chitosan-based gastrointestinal delivery systems

Chitosan, a natural polymer obtained by alkaline deacetylation of chitin, is non-toxic, biocompatible, and biodegradable. These properties make chitosan a good candidate for the development of conventional and novel gastrointestinal (GI) drug and gene delivery systems. The objective of this review is to summarize the recent applications of chitosan in oral and/or buccal delivery, stomach-specific drug delivery, intestinal delivery, and colon-specific drug delivery. The use of chitosan for targeting of drugs to each of these sites in the GI tract is illustrated by examples supported by in vivo studies. Chitosan appears to be a promising material for GI drug and gene delivery applications as many derivatives and formulations are being examined.

Probing depth changes following 2 years of periodontal maintenance therapy including adjunctive controlled release of chlorhexidine

BACKGROUND

Multicenter clinical trials have established that the adjunctive use of the subgingival controlled release of chlorhexidine, (CHX chip), significantly reduces probing depth (PD), improves clinical attachment levels, and reduces bleeding on probing compared to scaling and root planing (SRP) alone for periods of up to 9 months. The present report is based on a phase IV clinical trial to examine the adjunctive use of the CHX chip for routine periodontal maintenance therapy (RPMT) over 2 years.

METHODS

Eight hundred thirty-five (835) patients were recruited into the study. At baseline a CHX chip was placed in pocket sites with PD > or = 5 mm. The patients were scheduled to receive RPMT at 3-month intervals with repeated CHX chip placement at sites where the PD remained > or = 5 mm. Patients who did not attend the 24-month recall visit or who failed to attend 2 consecutive time frame examinations were excluded from the analyses.

RESULTS

The 595 patients included showed a continuous decrease in PD over 2 years of 0.95 mm. After 2 years, 23.2% of patients had at least 2 pockets showing a reduction in PD of 2 mm or more and 58.9% of the sites had been reduced to a PD of < 5 mm. Only 2.9% (n = 57) of the sites showed an increase in PD of > or = 2 mm. Adverse events were mild to moderate in nature and resolved spontaneously without medication.

CONCLUSION

The results of this Phase IV or follow-up trial indicate that the adjunctive use of the CHX chip is a clinically safe and effective treatment option for long-term management of chronic periodontitis.

Adjunctive effects to non-surgical periodontal therapy of systemic metronidazole and amoxycillin alone and combined. A placebo controlled study

BACKGROUND AND AIM

Several studies have reported adjunctive benefits to scaling and root planing (SRP) of systemic amoxycillin and metronidazole in the treatment of periodontal diseases. To date no comparisons have been made of these antimicrobials alone or in combination. The aim of this study was to compare the adjunctive benefits to SRP of amoxycillin and metronidazole alone and combined.

METHODS

66 subjects <46 years of age with advanced chronic periodontal disease participated in this randomised, double blind, 4 parallel treatment group designed study. All subjects received quadrant SRP and then were prescribed amoxycillin capsules (250 mg) and metronidazole tablets (200 mg) (AM) or lactate capsules and metronidazole (PM) or amoxycillin and calcium lactate tablets (AP) or lactate and calcium lactate (PP). All medication was 3 of each per day for 7 days. Subgingival plaque samples were obtained and probing depth (PD), loss of attachment (LOA), bleeding on probing (BOP), suppuration (SUPP) and plaque (DEP) were recorded pre-treatment, 1, 3 and 6 months post-treatment.

RESULTS

Final group sizes were: AM=15, PM=16, AP=16 and PP=15. PD improved in all groups. Treatment effects were highly significantly different and always greatest in the AM and least in the PP groups. Benefits of PM and AP over PP were also noted. LOA improved in all groups and showed the same highly significant treatment differences, again favouring AM. BOP improved in all groups, particularly in AM compared to the other groups. SUPP improved in all groups and was virtually eradicated in AM with differences among treatments highly significant. DEP changed little in any group and there were no significant differences among groups. Microbiological data showed significant differences in favour of AM compared to PP and PM for total aerobes and anaerobes at 1 month. P. intermedia counts were always lower in active groups compared to PP and reached significance for AM and AP at 1 month and AM and PM at 3 months.

CONCLUSION

The significant differences among treatment groups and the overall trend in the data, in line with other studies, support the considerable adjunctive benefits to SRP of amoxycillin and metronidazole combined in the treatment of advanced chronic periodontal disease.

Effect of chitosan on a periodontal pathogen Porphyromonas gingivalis

Local delivery systems of antimicrobial agents for treatment of the periodontal diseases received considerable attention during the past decade due to the disadvantages of the systemic administration. An ideal formulation should exhibit ease of delivery, a good retention at the application site, and a controlled release of the drug. The application of bioadhesive gels provides a long stay in the oral cavity, adequate drug penetration, high efficacy and acceptability. In dentistry and oral medicine, various applications of chitosan, which is a bioadhesive polymer have been proposed due to its favorable properties such as biocompatibility and biodegradability. The aim of this study was to determine the antimicrobial activity of chitosan formulations either in gel or film form against a periodontal pathogen, Porphyromonas gingivalis. The viscosity, bioadhesive properties and antimicrobial activity of chitosans at different molecular weight and deacetylation degree were evaluated in the absence or presence of chlorhexidine gluconate (Chx), incorporated into the formulations at 0.1 and 0.2% concentrations. The flow property of the gels were found to be suitable for topical application on the oral mucosa and to syringe into the periodontal pocket. Bioadhesion of the gels and films examined ex-vivo using fresh porcine buccal mucosa showed that both the film and gel formulations exert bioadhesive properties and was not affected by incorporation of Chx. Chitosan is shown to have an antimicrobial activity against P. gingivalis and this was higher with high molecular weight chitosan. The combination of chitosan with Chx showed a higher activity when compared to that of Chx alone, which would provide Chx application at lower concentrations thus avoiding its unwanted side effects. Chitosan films and gels seem to be promising delivery systems for local therapy of periodontal diseases with its bioadhesive property and antimicrobial activity.

In vitro antimicrobial susceptibilities of three Porphyromonas spp and in vivo responses in the oral cavity of cats to selected antimicrobial agents

OBJECTIVES

To determine in vitro susceptibility of Porphyromonas gingivalis, P salivosa and P circumdentaria to seven antimicrobial agents by agar dilution and Epsilometer test methods and to assess the effectiveness of these antimicrobial agents in reducing the numbers of each Porphyromonas spp in the oral cavity of 16 domestic cats.

DESIGN

A two-part prospective study involving in vitro antimicro-bial studies using Porphyromonas spp obtained from naturally occurring feline infections and in vivo antimicrobial response studies using client-owned cats with naturally occurring periodontal disease.

PROCEDURE

Isolates (n = 25) of three feline Porphyromonas spp from the oral cavity and oral-associated disease were tested for their in vitro susceptibility to amoxycillin, amoxycillin-clavulanate, benzylpenicillin, clindamycin, doxycycline, erythromycin and metronidazole, using agar dilution and Epsilometer test methods. Digoxigenin-labelled whole chromosomal DNA probes directed against P gingivalis VPB 3492, P circumdentaria NCTC 12469T and P salivosa VPB 3313 were used to quantify organisms taken from two sample sites at the gingival margins of these cats prior to, and 5 days after, treatment with one of four commonly used antimicrobial products (amoxycillin-clavulanate, clindamycin, doxycycline or spiramycin-metronidazole). The response to treatment was assessed clinically for each cat.

RESULTS

All isolates were susceptible in vitro to all seven antimicrobial agents using both methods. The numbers of P gingivalis were not reduced at the gingival sample sites by administration of amoxycillin-clavulanate for 5 days, although this treatment reduced the numbers of P salivosa and P circumdentaria to below detection levels in six of eight and two of three of sample sites, respectively; clinical improvement was not observed in cats treated with amoxycillin-clavulanate. Treatment with clindamycin, doxycycline or spiramycin-metronidazole resulted in clinical improvement and a marked reduction of all Porphyromonas isolates at the sample sites.

CONCLUSION

The Epsilometer test is a simple and accurate method for determining the minimum inhibitory concentration for P gingivalis, P salivosa and P circumdentaria. All strains were susceptible in vitro to all the antimicrobial agents tested although clinical improvement of gingival disease was not noted with amoxycillin-clavulanate when given for 5 days at usual doses. This appears to be the first report of the disparity between the in vivo and in vitro susceptibility of oral bacterial strains to amoxycillin-clavulanate in the veterinary dental literature. This also appears to be the first report in which clinical and microbiological responses to commonly used antimicrobial agents for periodontal disease in cats has been documented and quantified. It was shown that treatment with clindamycin, spiramycin-metronidazole or doxycycline not only produced a substantial reduction in the number of Porphyromonas spp (in the majority of cases to below detection levels), but also resulted in substantial clinical improvement. This would indicate that these antimicrobial agents are useful adjunctive therapy to mechanical debridement in domestic cats.

Fluoroquinolones in the treatment of Actinobacillus actinomycetemcomitans-associated periodontitis

BACKGROUND

Periodontitis patients harboring Actinobacillus actinmycetemcomitans (Aa) are prime candidates for systemic antibiotic therapy. Besides tetracycline and the combination of metronidazole and amoxicillin the fluoroquinolones are also believed to have antibacterial activity against Aa. The aim of the present study was to evaluate systemic ofloxacin therapy as adjunct to flap surgery.

METHODS

Twenty-five adult periodontitis patients with subgingival detection of Aa were treated with 2x200 mg/d ofloxacin for 5 days as adjunct to open flap surgery (test). Another 10 patients received only flap surgery (control). Probing depth (PD) and clinical attachment level (CAL) was recorded and subgingival plaque samples were cultivated on TSBV agar for detection of Aa at baseline as well as 3 and 12 months following therapy.

RESULTS

At 3 and 12 months following therapy mean PD at monitored sites in the test group changed from 6.8 mm (+/-1.3) to 3.6 mm (+/-1.0), 3.8 mm (+/-1.1) and CAL from 7.5 mm (+/-1.4) to 5.4 mm (+/-1.4), 5.5 mm (+/-1.3). In the control group PD changed from 6.5 mm (+/-0.7) to 4.0 mm (+/-1.7), 4.1 mm (+/-1.6) and CAL from 7.5 mm (+/-1.0) to 6.3 mm (+/-1.7), 6.4 mm (+/-1.8). P was <0.05 for CAL between groups. Three and 12 months following adjunctive systemic ofloxacin therapy, Aa was suppressed below detectable levels in 22 of 22, test patients, whereas Aa could not be recovered in only 2 of the 10 controls. (P<0.0001).

CONCLUSIONS

Systemic ofloxacin as adjunct to open flap surgery is able to suppress A. actinomycetemcomitans below detectable level in patients harboring this organism at baseline.

A comparative scanning electron microscopic study on the characteristics of demineralized dentin root surface using different tetracycline HCl concentrations and application times

BACKGROUND

The use of demineralizing agents has been reported to enhance the degree of connective tissue attachment to denuded roots. Of the agents used, tetracycline HCI has received the most attention.

METHODS

The purpose of this study was to evaluate and compare the SEM surface morphology of human root dentin following various concentrations and application times of tetracycline HCl. The surface characteristics were compared and the width of dentin tubule orifices were measured and analyzed. Twelve human teeth were collected and stored in distilled water after soft tissue removal using hand instruments. The apical third of each root was removed and remaining mid-root region was sectioned longitudinally through the root canal following removal of its cementum with a fine diamond bur. A total of 48 dentin specimens were randomly divided into 8 groups for conditioning at different tetracycline HCl concentrations, at 0, 10, 25, 50, 75, 100, 125, and 150 mg/ml. Application times for each group were 1, 3, and 5 minutes. Immediately following treatment procedures, the specimens were rinsed, fixed in GTA-PBF, dehydrated, and prepared for SEM. Each specimen was examined at 2 magnification values, representative fields photographed, and data tested by one-way ANOVA and paired t test statistical analysis.

RESULTS

Our results indicate that the use of tetracycline HCl solution between 50 mg/ml and 150 mg/ml showed a statistically significant opening of dentin tubules. All tetracycline HCl groups at 1, 3, and 5 minutes show smear layer removal from the dentin surface.

CONCLUSIONS

Dentin demineralization is not time dependent at all concentrations of tetracycline HCI.

Systemic doxycycline administration in the treatment of periodontal infections (I). Effect on the subgingival microbiota

Systemic doxycycline is one of the more common antimicrobial agents used in the treatment of periodontal infections and yet little is known of its effect on subgingival plaque composition during and after its administration. The purpose of the present investigation was to evaluate changes in subgingival plaque composition during and after 14 days of doxycycline administration. 20 subjects with adult periodontitis were randomly assigned to test (n = 10) and control (n = 10) groups. The subjects received full mouth clinical assessment of pocket depth, attachment level, BOP, gingival redness, suppuration and plaque accumulation at baseline and 90 days. All subjects received full mouth SRP at baseline and, additionally, the test group received 100 mg doxycycline daily for 14 days. Subgingival plaque samples were taken from the mesial surface of up to 28 teeth in each subject at baseline and 90 days. In addition, plaque samples were taken from 2 randomly selected teeth at 3, 7 and 14 days during and after antibiotic administration. Control subjects were sampled at the same time points. Counts of 40 subgingival species were determined using checkerboard DNA-DNA hybridization and fluorescent detection. Significance of differences between test and control groups was determined at each time point using the Mann Whitney test. Significance of changes over time within test and control groups was determined using the Quade test. A modest but significant reduction in mean pocket depth from baseline to 90 days occurred in both test and control groups. A significant decrease in the % of sites with gingival redness occurred in the test group. There were no significant differences in proportions between test and control groups for 33 of the test species at any time point. Test subjects exhibited lower proportions of 4 Actinomyces species and an increase in 3 Streptococcus species during antibiotic administration. After cessation of doxycycline, Actinomyces sp. increased while Streptococcus sp. returned to baseline proportions. The relationship between these 2 genera appeared to be reciprocal; an increase in one was accompanied by a decrease in the other. Periodontal pathogens including B. forsythus, P. gingivalis, T. denticola and A. actinomycetemcomitans were not significantly altered by oral administration of doxycycline using conventional therapeutic dosage.

Longitudinal effect of non-surgical treatment and systemic metronidazole for 1 week in smokers and non-smokers with refractory periodontitis: a 5-year study

BACKGROUND

Periodontitis consists of a mixture of diseases, most of which respond favorably to traditional mechanical therapy. It is now recognized that advanced periodontitis does not always respond to conventional management with scaling, periodontal surgery, and oral hygiene measures. However, various types of antibiotics given systemically or locally improve the success rate of periodontal therapy. In short-term studies, it has been shown that metronidazole, when systemically administered after debridement, resulted in treatment benefits including less need for surgical intervention.

METHODS

In this double-blind study, we evaluated periodontal treatment involving initial non-surgical treatment, systemic administration of metronidazole for 1 week, and then follow-ups for scaling and root planing every 6 months, for 5 years. The study population consisted of 64 subjects (37 smokers and 27 non-smokers), mean age 36.3 (+/-3.0 SD) years, with severe periodontal disease. After initial scaling and root planing, patients were randomly assigned to the intervention or placebo groups: 400 mg metronidazole or a placebo administered at 8-hour intervals for 1 week. The participants underwent an extensive clinical periodontal examination. Gingival crevicular fluid (GCF) was analyzed for spirochetes and granulocytes. Samples were cultured for Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas gingivalis (Pg.), and Prevotella intermedia (Pi.).

RESULTS

The number of patients infected with A.a., Pg., Pi., and spirochetes decreased during the study. Most patients who harbored spirochetes at the end of the study had these microorganisms at the beginning. Smokers responded less favorably to periodontal therapy than non-smokers. Non-smoking patients who required only non-surgical therapy in the intervention group showed statistically significant improvement in the clinical parameters after 5 years. Patients with complete healing, defined as the absence of inflamed sites > or =5 mm, after 5 years were found only in the intervention group. The patients considered healthy after 5 years were the same patients found to be healthy after 6 months.

CONCLUSIONS

Decisive factors in the sustained long-term improvement of patients who respond satisfactorily to treatment are probably initial scaling and root planing; a brief course of metronidazole; and regular follow-up examinations at 6-month intervals for oral hygiene and scaling and root planing.

Virulence factors of Actinobacillus actinomycetemcomitans

A. actinomycetemcomitans has clearly adapted well to its environs; its armamentarium of virulence factors (Table 2) ensures its survival in the oral cavity and enables it to promote disease. Factors that promote A. actinomycetemcomitans colonization and persistence in the oral cavity include adhesins, bacteriocins, invasins and antibiotic resistance. It can interact with and adhere to all components of the oral cavity (the tooth surface, other oral bacteria, epithelial cells or the extracellular matrix). The adherence is mediated by a number of distinct adhesins that are elements of the cell surface (outer membrane proteins, vesicles, fimbriae or amorphous material). A. actinomycetemcomitans enhances its chance of colonization by producing actinobacillin, an antibiotic that is active against both streptococci and Actinomyces, primary colonizers of the tooth surface. The fact that A. actinomycetemcomitans resistance to tetracyclines, a drug often used in the treatment of periodontal disease, is on the rise is an added weapon. Periodontal pathogens or their pathogenic products must be able to pass through the epithelial cell barrier in order to reach and cause destruction to underlying tissues (the gingiva, cementum, periodontal ligament and alveolar bone). A. actinomycetemcomitans is able to elicit its own uptake into epithelial cells and its spread to adjacent cells by usurping normal epithelial cell function. A. actinomycetemcomitans may utilize these remarkable mechanisms for host cell infection and migration to deeper tissues. A. actinomycetemcomitans also orchestrates its own survival by elaborating factors that interfere with the host's defense system (such as factors that kill phagocytes and impair lymphocyte activity, inhibit phagocytosis and phagocyte chemotaxis or interfere with antibody production). Once the organisms are firmly established in the gingiva, the host responds to the bacterial onslaught, especially to the bacterial lipopolysaccharide, by a marked and continual inflammatory response, which results in the destruction of the periodontal tissues. A. actinomycetemcomitans has at least three individual factors that cause bone resorption (lipopolysaccharide, proteolysis-sensitive factor and GroEL), as well as a number of activities (collagenase, fibroblast cytotoxin, etc.) that elicit detrimental effects on connective tissue and the extracellular matrix. It is of considerable interest to know that A. actinomycetemcomitans possesses so many virulence factors but unfortunate that only a few have been extensively studied. If we hope to understand and eradicate this pathogen, it is critical that in-depth investigations into the biochemistry, genetic expression, regulation and mechanisms of action of these factors be initiated.

The uptake of two androgen substrates by cultured human gingival fibroblasts in response to minocycline and metabolic studies using a cell-free system

The uptake of two androgen substrates by cultured fibroblasts and the anabolic response of homogenates of cultured gingival fibroblasts to minocycline were investigated. Monolayer cultures of confluent fibroblasts were incubated with [14C]testosterone/[14C]4-androstenedione for timed intervals in the presence or absence of optimal concentrations of minocycline. The intracellular uptake of androgens was quantified by radio-isotope counts on cell digests. Confluent gingival fibroblasts were homogenized by snap freezing/rapid thawing and duplicate incubations were made in phosphate-buffered saline (pH 6.5) with radiolabelled androgens, in the presence or absence of minocycline, for 24 h. At the end of the incubation period the buffer was extracted for radioactive metabolites, analysed and quantified with a radio-isotope scanner. There were 30% increases in the uptake of androgen substrates in the presence of minocycline (n=3; p < 0.01; one-way ANOVA). With the metabolic studies there were 2-3-fold increases in the formation of dihydrotestosterone from [14C]testosterone and [14C]4-androstenedione, respectively (n=4; p < 0.001; one-way ANOVA), and 4-fold/2-fold increases in the formation of 4-androstenedione/ testosterone from these substrates (n=4; p < 0.001) in response to an optimal concentration of 20 microg/ml of minocycline, compared with control incubations. The presence of minocycline in the incubate significantly increased the activity of the steroid-metabolizing enzymes. This increase might result from increased intracellular availability of steroid substrate and enhanced metabolic activity. Homogenates of cultured gingival fibroblasts are a useful model for studying the anabolic potential of minocycline in gingiva, using C19 steroid substrates.

An in vivo study of the chlorhexidine release profile of the PerioChip in the gingival crevicular fluid, plasma and urine

The release profile of chlorhexidine from the PerioChip (Chip), a biodegradable local delivery system that contains 2.5 mg of chlorhexidine gluconate (CHX) in a cross-linked hydrolyzed gelatin matrix, into the gingival crevice, was evaluated in an in vivo, open label, single-center, 10-day pharmacokinetic study conducted on 19 volunteers with chronic adult periodontitis. Each volunteer had a single chip inserted into each of 4 selected pockets, with probing pocket depths of between 5-8 mm, at time 0. Gingival crevicular fluid (GCF) samples were collected using filter paper strips prior to Chip placement and at 2 h, 4 h, 24 h and 2, 3, 4, 5, 6, 8, and 9 days post-Chip placement. The GCF volume was measured using a calibrated Periotron 6000. Blood samples were collected at times 0, 1, 4, 8, 12 h and 5 days post-dosing. Urine was collected as a total 24-h specimen immediately post-dosing and 2 single samples at time 0, prior to dosing, and 5 days. The CHX was eluted from the paper strips and the CHX levels in GCF, blood and urine quantified using HPLC. The results indicate an initial peak concentration of CHX in the GCF at 2 h post-Chip insertion (2007 microg/ml) with slightly lower concentrations of between 1300-1900 microg/ml being maintained over the next 96 h. The CHX concentration then progressively decreased until study conclusion with significant CHX concentrations (mean=57 microg/ml) still being detectable at study termination. CHX was not detectable in any of the plasma or urine samples at any time point during the study. These results indicate that the PerioChip can maintain clinically effective levels of CHX in the GCF of periodontal pockets for over 1 week with no detectable systemic absorption.

Oral and periodontal tissue. Maintenance, augmentation, rejuvenation, and regeneration

This article discusses the controversies, usefulness, and limitations of oral and periodontal tissue maintenance, augmentation, rejuvenation, and regeneration in the dog and cat. It details many of the specialized materials and techniques used in these procedures in attempts to re-establish healthy conditions within the periodontium. Bone loss following tooth extraction is discussed with consideration as to which teeth should have alveolar ridge maintenance procedures and the important reasons as to why. Radiographs show the degree of improvement demonstrated in treatment of various cases involving bone loss from periodontal disease, treatment of bone injuries with oral fractures and their prevention.

Effects of combined topical metronidazole and mechanical treatment on the subgingival flora in deep periodontal pockets in cuspids and bicuspids

The Effect on the subgingival microflora of a single topical administration of a 95% collagen and 5% metronidazole device in combination with debridement was investigated in 30 adult periodontitis patients in comparison with mechanical treatment alone. For each patient, plaque samples from test and control sites in cuspids and bicuspids were collected for culture and enumeration of total anaerobically cultivable bacteria (TA), black-pigmented anaerobes (BPA), and Actinobacillus actinomycetemcomitans (Aa). Spirochetes and fusiforms were quantified by direct microscopic examination after Giemsa staining. A decrease was observed for all parameters, and a significant difference in comparison with the control group was found for fusiforms. After treatment, a lower number of Aa positive sites were observed in the test group (13/25). These results show that a single application of topical metronidazole seems to be effective as adjunctive antimicrobial treatment in adult periodontitis.

Clinical evaluation of tetracycline HCl conditioning in the treatment of gingival recessions. A comparative study

Thirty Class I and Class II recessions in 30 patients were treated with a modified subepithelial connective tissue graft procedure. Fifteen recessions in the test group received a tetracycline hydrochloride (50 mg/ml) root treatment for 5 minutes (TTC-HCl group); the remaining 15 recessions composed the control group and received a citric acid root treatment for 3 minutes (CA group). Clinical assessments were taken at baseline and at 6 months. The differences between treatments were not statistically significant. In the central area of the recession, the mean percentage of root coverage was 81.7% corresponding to a mean percentage of 79.3% and 84.0% for the TTC-HCl and the CA group, respectively. In the test group, 6 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 57.8%. In the control group, 8 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 43.6%. The mean surface area of root exposure was reduced from 11.53 mm2 and 13.30 mm2 to 0.34 mm2 and 0.29 mm2 for the TTC-HCl group and the CA group, respectively. This reduction corresponds to a mean percentage of 97.4% root coverage for both groups. Within the limits of this study, the results indicate that tetracycline hydrochloride and citric acid root conditioning have comparable clinical effects in root coverage surgical therapy. The data also suggest that the measurement of the surface area of the recession is a more accurate criterion in the evaluation of the mean percentage of root coverage than a single central vertical linear measurement.

Sustained local delivery of chlorhexidine in the treatment of periodontitis: a multi-center study

The safety and efficacy of a degradable, subgingivally placed drug delivery system containing 2.5 mg chlorhexidine (CHX) were evaluated in a randomized, blinded, multi-center study of 118 patients with moderate periodontitis. A split-mouth design was used to compare the treatment outcomes of scaling and root planing (SRP) alone with the combined use of SRP and the CHX in pockets with probing depths of 5 to 8 mm. The two maxillary quadrants were used for the two treatment arms of the study. Scaling and root planing was performed at baseline only, while the CHX was inserted both at baseline and at 3 months. Clinical and safety measurements including probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) as well as gingivitis, plaque, and staining indices were recorded at baseline, and at 1, 3, and 6 months. The average PD reduction in the CHX-treated sites was significantly greater than in the sites receiving SRP alone at both 3 and 6 months with a mean difference of 0.42 mm (P < or = 0.01) at 6 months. The reduction in CAL at the treated sites was greater than at the SRP sites, although the difference was statistically significant at the 6-month visit only. An analysis of patients with initial probing depths of 7 to 8 mm (n = 56) revealed a significantly greater reduction in PD and CAL in those pockets treated with CHX compared to SRP at both 3 and 6 months. The mean differences between test and control sites at 6 months were 0.71 mm and 0.56 mm PD and CAL respectively.

Subgingival delivery of therapeutic agents in the treatment of periodontal diseases

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

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

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

Detection and prevalence of the tetracycline resistance determinant Tet Q in the microbiota associated with adult periodontitis

Subgingival plaque samples were collected from 68 patients with a history of moderate to severe adult periodontitis and enumerated on Trypticase-soy blood agar plates, with and without tetracycline at 4 micrograms/ml. Each different colony morphotype was enumerated, and a representative colony was subcultured for identification and examined for the tetracycline resistance gene tet(Q) by polymerase chain reaction (PCR) amplification and DNA hybridization, using a fragment of tetA(Q)2 from Bacteroides fragilis 1126. PCR primers (5'-GGCTTCTACGACATCTATTA-3' and 5'-CATCAACATTTATCTCTCTG-3') were chosen to amplify a 755 bp region of tet(Q). The subgingival plaque samples were also tested by PCR. Approximately 12% of the total cultivable flora was resistant to tetracycline, and the percentage of the tetracycline-resistant cultivable flora with the tet(Q) gene varied greatly from one patient to another with a range from 0.0 to 67%. Half of the 68 subgingival plaque samples were positive or weakly positive for tet(Q) by PCR. Approximately 15% of the 210 isolates subcultured with resistance to tetracycline, (> or = 4 micrograms/ml) contained tet(Q), and 60% contained tet(M). All of the tet(Q)-resistant isolates were gram-negative anaerobic bacilli and included all of the Prevotella and Bacteroides isolates.

Local and systemic chemotherapy in the management of periodontal disease: an opinion and review of the concept

Periodontal disease appears to arise from the interaction of pathogenic bacteria with a susceptible host. The main aims of disease management have been to establish a high standard of oral hygiene and to professionally and thoroughly debride the root surface Chemical agents could be considered for both aspects of management. Chemoprevention using supragingivally delivered agents such as chlorhexidine may be questioned for value in the pre-treatment hygiene phase but have well-established efficacy immediately preoperatively and during the post-operative weeks. Long-term maintenance use of chlorhexidine is problematic due to local side effects. Antiplaque toothpastes show modest benefits to gingivitis but are not proven to prevent recurrence of periodontitis. Chemotherapy may be directed at subgingival plaque, using antimicrobials, or at the host response using anti-inflammatory agents. Antimicrobials can be locally or systemically delivered. In most cases antimicrobial chemotherapy should be considered adjunctive to mechanical debridement. The advantages of local and systemic chemotherapy must be balanced against the disadvantages and potential side effects of agents. Antimicrobial chemotherapy offers little or no benefit to the treatment of most chronic adult periodontitis patients and should be reserved for the more rapid or refractory types of disease, and after the debridement phase. Despite the large number of studies there are insufficient comparative data to support any one local delivery system or systemic regimen as superior to another. Systemic versus local antimicrobials have not been compared to date. Host response modifying drugs such as non-steriodal anti-inflammatory drugs (NSAIDS) offer the potential to reduce breakdown and promote healing, including bone regeneration. However until more data are available, NSAIDs should not be used in the management of chronic periodontal diseases, there being no specific agent(s) or regimen established for use. Chemotherapy has an important place in the management of chronic periodontal diseases but routine use must be considered as an over prescription of these valuable agents.

Slow release of tetracycline hydrochloride from a cellulose membrane used in guided tissue regeneration

The objective of this study was to evaluate if the biologic membrane utilized for GTR can be impregnated by tetracycline hydrochloride and if the chemotherapeutic agent, once impregnated, can be released in minimal inhibitory concentrations for a period compatible with clinical application. Initially, an in vitro study was done with cellulose membranes cut in pieces measuring 9 cm2. A volume of 100 microliters containing a 72,000 micrograms/ml solution of tetracycline was dispensed onto each fragment, and dried for 70 minutes at 37 degrees C. Four pieces measuring 0.5 cm2 were cut from different points of the 9 cm2 membrane (presumably, containing 400 micrograms of tetracycline), placed in test tubes containing 4 ml of sterile deionized water, and agitated for 2 minutes. A standard curve was made from known concentrations of tetracycline and compared to 10 microliters of the test solutions obtained by the elution of the 0.5 cm2 fragments. The concentrations were determined through the bioassay technique in 3 duplicate experiments. The samples recovered from the membrane fragments had a mean of 101 micrograms/ml of tetracycline liberated, demonstrating that the membrane was impregnated homogeneously by the chemotherapeutic agent. In a second phase, an in vivo study was carried out to determine the length of time the drug was liberated from the membranes and at which concentrations, in the presence of an inflammatory process. Fourteen 0.5 cm2 fragments containing 400 micrograms of tetracycline were placed in 14 polypropylene chambers containing 200 microliters of thioglycolate medium. The chambers were implanted in the peritoneal cavities of 14 mice, one chamber per animal, and left in from 1 to 14 days. They were then removed and the concentrations of tetracycline determined from 20 microliters samples using a bioassay. The results showed that the antibiotic was released slowly from the 1st through the 12th day in decreasing concentrations that varied from 218 to 20.8 micrograms/ml. The impregnated cellulose membrane can probably be used in GTR acting as a membrane and as a slow-release device, liberating the chemotherapeutic agent in concentrations high enough to eliminate periodontopathic microorganisms.

Clinical and microbiological changes associated with the use of 4 adjunctive systemically administered agents in the treatment of periodontal infections

The purpose of the present investigation was to assess the effects of periodontal surgery and 4 systemically administered agents, Augmentin, tetracycline, ibuprofen or a placebo on clinical and microbiological parameters of periodontal disease. 98 subjects were monitored at 2-month intervals at 6 sites per tooth for clinical parameters. Subgingival plaque samples were taken from the mesial surface of each tooth at each visit and evaluated for their content of 14 subgingival species using DNA probes and a colony lift method. 40 subjects who exhibited loss of attachment > 2.5 mm at 1 or more sites during longitudinal monitoring were treated using modified Widman flap surgery at sites with probing pocket depth > 4 mm, subgingival scaling at all other sites and were randomly assigned 1 of the 4 agents. Treatment was completed within 30 days during which time the subject took the assigned agent. Overall, subjects exhibited a mean attachment level "gain" of 0.34 +/- 0.10 mm (SEM) and a mean pocket depth reduction of 0.62 +/- 0.09 mm 10 +/- 4 months post-therapy. However, certain subjects in each treatment group showed a poor response. Subjects receiving antibiotics exhibited significantly more attachment level "gain" (0.57 +/- 0.15 mm, SEM) than subjects receiving either ibuprofen or a placebo (0.02 +/- 0.10). The differences between Augmentin and tetracycline groups were not significant, nor were the differences between ibuprofen and placebo. 10 months post-therapy, there was a reduction in the number of sites colonized in any subject group by detectable levels (10(3)) of P. gingivalis. Species showing similar reductions were B. forsythus, P. intermedia and P. micros. Subjects receiving systemically administered antibiotics had a significant increase in the proportion of sites colonized by C. ochracea coupled with a greater decrease in the number of sites colonized by P. gingivalis, B. forsythus, P. intermedia and P. micros post-therapy than subjects not receiving antibiotics. The results of this investigation indicate that adjunctive systemic antibiotics increase periodontal attachment "gain" and decrease the levels of some suspected periodontal pathogens in subjects with evidence of current disease progression.

In vitro activity of tetracyclines, macrolides, quinolones, clindamycin and metronidazole against periodontopathic bacteria

We re-evaluated several antibiotics including newer ones, for their in vitro killing activity, as well as their inhibitory activity, against clinical isolates of periodontopathic bacteria. Tetracyclines were active against Porphyromonas gingivalis, and were highly active against Prevotella intermedia, but demonstrated only a low killing activity against Actinobacillus actinomycetemcomitans. Rokitamycin, a new macrolide, and clindamycin were highly active against P. gingivalis and P. intermedia, but showed very weak killing activity against A. actinomycetemcomitans. Quinolones demonstrated excellent bactericidal activity against A. actinomycetemcomitans, and good inhibitory and bactericidal activity against P. gingivalis and P. intermedia. Metronidazole had an activity almost equivalent to quinolones against P. gingivalis and P. intermedia; but it was the least active against A. actinomycetemcomitans.

Detection and incidence of the tetracycline resistance determinant tet(M) in the microflora associated with adult periodontitis

Subgingival plaque samples were collected from 68 patients with adult periodontitis, enumerated on Trypticase-soy blood agar plates, with and without tetracycline at 4 micrograms/ml, and incubated anaerobically for 5 days. Each different colony morphotype was enumerated, and a representative colony was subcultured for identification and examined for the tetracycline resistance gene tet(M). Both PCR amplification and DNA hybridization, using a fragment of tet(M) from Tn1545, were used to detect tet(M). The PCR primers (5'-GACACGCCAGGACATATGG-3' and 5'-TGCTTTCCTCTTGTTCGAG-3') were chosen to amplify a 397 bp region of tet(M). Tetracycline-resistant bacteria represented approximately 12% of the total viable count. The percentage of tet(M)-positive bacteria in the tetracycline resistant microflora varied from < or = 0.05 to 83% (mean of 10%). tet(M) was detected in 60% of 204 tetracycline-resistant strains subcultured and identified. The tet(M) containing strains consisted of streptococci (55%, mainly S. intermedius, S. oralis, S. sanguis, and Streptococcus SM4), Actinomyces D01 (14%), Bifidobacterium D05 (11%), and Veillonella spp. (10%). Tetracycline-resistant strains in which tet(M) was not detected included the Prevotella and Bacteroides species (41%, mainly Bacteroides D28, P. intermedia, P. nigrescens, and P. oris). These results suggest that tet(M) is widely spread in the adult periodontal microflora, but it appears, with the exception of S. intermedius, to be mainly associated with microorganisms not considered to be periodontopathogens. Assessment of other tetracycline-resistant genes in oral organisms is needed to fully evaluate the nature of resistance to this antibiotic in the oral flora.

Subinhibitory concentrations of cefpodoxime alter membrane protein expression of Actinobacillus actinomycetemcomitans and enhance its susceptibility to killing by neutrophils

The aim of the present study was to determine the effect of the antibiotic cefpodoxime on the gram-negative periodontopathic microorganism Actinobacillus actinomycetemcomitans and its interaction with elements of the host immune system. Growth of A. actinomycetemcomitans in subinhibitory concentrations of cefpodoxime induced morphological changes in the bacteria, causing the organisms to grow as filaments rather than coccobacilli. Growth in cefpodoxime did not render these bacteria susceptible to killing by serum, nor did it abrogate the requirement for serum opsonins to support the bactericidal activity of neutrophils. Cefpodoxime enhanced the susceptibility of A. actinomycetemcomitans to the bactericidal activity of neutrophils. In the presence of suitable opsonins, neutrophils were able to kill four times as many cefpodoxime-induced A. actinomycetemcomitans filaments as untreated A. actinomycetemcomitans CFU. This effect was due to antibiotic actions on the bacterium and not on the neutrophil. At inhibitory concentrations, the bactericidal activities of cefpodoxime and neutrophils were additive, and cefpodoxime did not interfere with the normal functioning of the neutrophils. Concomitant with these morphological and functional changes, the expression of two outer membrane proteins (66 and 29 kDa) and one inner membrane protein (57 kDa) was decreased in A. actinomycetemcomitans grown in cefpodoxime. The concentration range over which cefpodoxime is effective against A. actinomycetemcomitans in vivo may be extended by the ability of subinhibitory concentrations to enhance the susceptibility of this organism to host immune defenses.

The effect of a single application of subgingival antimicrobial or mechanical therapy on the clinical parameters of juvenile periodontitis

Twenty-six (26) patients, 18 female and 7 male, aged 16 to 25 years (mean age 19.03 +/- 2.2 years) previously diagnosed as suffering from localized juvenile periodontitis were randomly assigned to one of the following treatment groups: 9 patients acted as controls; 8 received subgingival chlorexidine gel; and 9 had subgingival tetracycline paste application. All treatment modalities resulted in a pronounced improvement in PI, GI, and GI-S by 12 weeks (P < 0.001). The mean probing depths also decreased, but there were no significant differences found between the three groups. However, when the interproximal sites of the 3 groups were examined separately from the buccal and lingual sites, it was found that there was a significant (P < 0.05) difference between the probing depths, with the control group showing the greatest reduction of 2.58 mm and the chlorhexidine group showing the least reduction of 1.37 mm. It was concluded that a single application of topical subgingival tetracycline did not result in any short-term improvement over that achieved by standard non-surgical therapy in the clinical parameters of these localized juvenile periodontitis patients.

Effects of tetracycline-containing gel and a mixture of tetracycline and citric acid-containing gel on non-surgical periodontal therapy

The purpose of this study was to assess the clinical and microbiological effects of a newly developed root conditioning gel system containing tetracycline or a mixture of tetracycline and citric acid on non-surgical periodontal therapy. Sixty-four (64) single-rooted teeth with a probing depth of 4 to 6 mm were randomly subjected to one of the following four treatments; 1) root planing alone (RP group); 2) tetracycline-containing gel alone (TCG group); 3) root planing plus tetracycline-containing gel (RP + TCG group); or 4) root planing plus a mixture of tetracycline and citric acid-containing gel (RP + TC-CAG group). Probing depth, attachment level, and tooth mobility were measured and the presence of dental plaque and gingival inflammation was recorded at baseline and after 2, 4, 8, and 12 weeks. Subgingival plaque samples from each site were collected at the same visits and examined with phase contrast microscopy for proportions of motile rods and spirochetes. Plaque index, gingival sulcus bleeding index (SBI), probing depth, and attachment level decreased significantly in all groups compared to the baseline values (P < 0.05). A significant decrease in probing pocket depth was noted after 12 weeks in RP + TC-CAG group compared to the other groups (P < 0.05). Significantly more gain in attachment was detected in the RP + TC-CAG group compared to the TCG group (P < 0.05). Tooth mobility scores also decreased later in the study. A significant decrease in the proportion of motile rods was found primarily in the RP + TC-CAG group.(ABSTRACT TRUNCATED AT 250 WORDS)