Local delivery of tetracycline: from concept to clinical application

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.

In vitro assessment of the antimicrobial activity of tetracycline hydrochloride diluted in three different vehicles against Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum

Background:

The development and progression of periodontal diseases is a result of the dynamic interaction of microorganisms within their habitat, and changes in this habitat generate a dysbiotic state. Fusobacterium nucleatum and Prevotella intermedia are bridging microorganisms between the pioneer communities and other microorganisms responsible for periodontitis such as Porphyromonas gingivalis. Tetracycline hydrochloride (TTC-HCl) is commonly used as a coadjutant in periodontal treatment in the form of an antiseptic. However, there are no clear dilution or concentration protocols.

Objective:

This study aimed to evaluate the in vitro antimicrobial activity of TTC-HCl diluted in sterile water, saline solution, and 2% lidocaine with epinephrine 1:80,000 at concentration of 125, 250, and 500 mg, at three time points– 30, 60, and 120 s – on P. intermedia, F. nucleatum, and P. gingivalis using the Kelsey–Maurer technique.

Materials and Methods:

The antimicrobial activity of TTC-HCl was evaluated at the proposed concentrations and times, dissolved in the different vehicles at pH 1.9 and 7.0, on F. nucleatum, P. intermedia, and P. gingivalis. The Kelsey–Maurer test was used to verify the presence or absence of colony-forming units. Each test was performed in triplicates with its respective viability controls.

Results:

Inhibition of F. nucleatum, P. intermedia, and P. gingivalis was achieved with TTC-HCl at all concentrations, dissolved in distilled water, saline solution, and 2% lidocaine with epinephrine 1:80,000 for all times.

Conclusions:

The results show that TTC-HCl is a good antimicrobial alternative against F. nucleatum, P. intermedia, and P. gingivalis regardless of the vehicle in which it was dissolved, concentration, pH, or time used in this investigation.

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.

Adjunctive antimicrobial chemotherapy based on hydrogen peroxide photolysis for non-surgical treatment of moderate to severe periodontitis: a randomized controlled trial

Treatment of severe periodontitis with non-surgical therapy remains challenging in dentistry. The present study aimed to evaluate the clinical efficacy of hydrogen peroxide (H₂O₂) photolysis-based antimicrobial chemotherapy adjunctively performed with root debridement (RD) for moderate to severe periodontitis. A randomized controlled trial was conducted that included 53 patients with 142 test teeth. The test teeth were randomly assigned to one of three treatment groups: Group 1, RD + H₂O₂ photolysis; Group 2, RD followed by administration of a local drug delivery system (minocycline chloride gel); or Group 3, RD alone. Clinical and microbiological examination were performed for up to 12 weeks following treatment. Probing pocket depth (PPD) and bleeding on probing (BoP) were improved after each treatment session. At 12 weeks, Group 1 had achieved significantly lower PPDs than the other groups, though there were no significant differences in BoP between Group 1 and the other groups. Counts of Porphyromonas gingivalis, a known periodontal pathogen, in Group 1 were significantly lower than those in Group 3, and were comparable to those in Group 2. Therefore, it is suggested that H₂O₂ photolysis treatment can be used as a novel adjunctive antimicrobial chemotherapy for non-surgical periodontal treatment.

Inhibitors of bacterial protease enzymes for periodontal therapy

Locally applied therapeutic agents have become established in the treatment of periodontal disease. Inhibition of human metalloproteases by metal-chelating antibiotics contributes to the utility of local therapy. Adding inhibitors of bacterial proteases might extend and improve local therapy. The periodontal pathogen Porphyromonas gingivalis (Pg) produces two extracellular cysteine proteases (gingipains Rgp and Kgp) that are virulence factors and contribute to destruction of oral tissues. Our aims were to compare efficacy of protease inhibitors against gingipains and evaluate bactericidal activity of the inhibitors. Protease activity was measured in fluorescent assays with specific Rgp and Kgp substrates. Bacterial viability was measured with BacLight™ (Invitrogen, Inc., Carlsbad, CA) reagents. Pairs of inhibitors of Rgp and Kgp, respectively, were leupeptin and cathepsin B inhibitor II, KYT-1 and KYT-36, and PPACK and Z-FK-ck. The cysteine-protease inhibitor E64 was also tested. Rgp activity was higher than Kgp activity, and activity was higher in Pg 33277 and 49417 cell suspensions than in media. Concentrations required for 50% inhibition of Rgp in cell suspensions were 2 × 10-9, 2 × 10-9, 2 × 10-8, and 5 × 10-5 M for KYT-1, PPACK, leupeptin, and E64, respectively. Concentrations required for 50% Kgp inhibition were 5 × 10-10, 1 × 10-9, and 5 × 10-8 M for Z-FK-ck, KYT-36, and cathepsin B inhibitor II. E64 did not inhibit Kgp. Inhibition of Rgp could be accounted for by competition for binding between the arginine residue of the substrate and the guanidinobutane portion of E64. PPACK was the least selective, with a 10-fold difference in concentrations that inhibited Rgp and Kgp. KYT-1 and Z-FK-ck inhibited both Rgp and Kgp, but inhibitory concentrations differed by 10,000-fold. At up to 1 × 10-4 M, only Z-FK-ck was bactericidal. KYT-1 and KYT-36 were remarkably effective even when used in cell suspensions in which bacterial proteins could bind inhibitors or compete for binding to gingipains. These inhibitors might prove useful as an addition to locally applied therapeutic agents.

Single use of tetracycline with and without diclofenac sodium as local drug delivery in pocket therapy: a clinico-microbiological study

AIM

  Local drug delivery is a non-surgical method in the treatment of periodontitis. Different chemotherapeutic agents are used for local drug delivery; one such agent is tetracycline, a broad-spectrum antibiotic. Recent studies have also shown that the use of non-steroidal anti-inflammatory drugs reduces pro-inflammatory cytokines and acts as host modulator. Thus, an attempt was made to compare and evaluate the efficacy of tetracycline alone and in combination with diclofenac sodium as a local drug delivery.

METHODS

  A total of 36 sites with chronic periodontitis were divided into three groups with 12 sites each (i.e. group A, antibiotics alone; group B, antibiotics in combination with non-steroidal anti-inflammatory drugs; and group C, control group). For all the groups, the following parameters (plaque index, papillary bleeding index, probing pocket depth, and microbial analysis) were assessed and statistically analyzed.

RESULTS

  The antibiotic and non-steroidal anti-inflammatory drug combination group showed a statistically-significant improvement in clinical parameters and a shift in microbial flora when compared to the group with antibiotics alone. However, the control group failed to show any statistically-significant improvement.

CONCLUSION

  Antibiotics in combination with non-steroidal anti-inflammatory drugs are more efficient than using antibiotics alone as local drug delivery for the treatment of periodontal pockets.

A scanning electron microscopic study of the contraceptive vaginal ring

OBJECTIVE

To compare by electron microscopy the surface of vaginal contraceptive rings before and after use.

METHODS

A single ring was worn for 28 days by a volunteer with normal vaginal flora. This worn ring was then cut in half, with one half placed directly into fixative and the other half rinsed to remove visible mucus prior to being placed into the fixative. Another ring was taken directly from the package and placed in fixative. The surfaces of the three ring samples were studied by scanning electron microscopy at varying magnifications to ascertain if there was penetration of bacteria into the vinyl polymer or if the ring surface was altered with 1 month of use.

RESULTS

The ring half placed directly into fixative with visible mucus had cellular debris on its surface but no evidence of material penetration. The other half of the ring worn for 28 days and rinsed before fixation had a similar surface appearance to the unused ring.

CONCLUSIONS

The surface of the ethylene vinyl acetate contraceptive vaginal ring is remarkably uniform and after 1 month of use was without visible evidence of erosion, embedded bacteria or structural changes compared to an unused ring.

Microbial shifts after subgingival debridement and formation of bacterial resistance when combined with local or systemic antimicrobials

Antibiotics have played a major role in the improvement of life expectancy in the last 50 years and have led many to believe that bacterial infections were about to vanish as a disease entity of any importance. Emerging problems resulting from a widespread use of antibiotics have modified the general perception of the capabilities of antimicrobial agents. Over the years, bacteria have become increasingly resistant to formerly potent antimicrobial agents, including some antiseptics. The use of antimicrobials may also disturb the delicate ecological equilibrium of the body, allowing the proliferation of resistant bacteria or non-bacterial micro-organisms. This shift may initiate new infections that are worse than the ones originally treated. No antimicrobial drug is absolutely non-toxic and the use of an agent carries accompanying risks. This paper discusses the development and occurrence of antimicrobial resistance in the subgingival flora towards antiseptics and local or systemic antibiotics and is focussed on the question: how can the outcome of periodontal therapy with/without antimicrobials be improved?

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.

Sustained release of silver from periodontal wafers for treatment of periodontitis

Periodontal wafers intended to treat the underlying infections in patients with periodontitis have been developed. The wafers consist of poly(lactic-co-glycolic acid) as a primary bioerodible polymeric component, poly(ethylene glycol) as a plasticizer and encapsulation aid, and silver nitrate as the antimicrobial agent. The wafers are capable of sustained in vitro release of bioactive silver for at least 4 weeks. The wafers exhibit silver release that follows erosion kinetics, confirming a bulk erosion/release mechanism. In clinical evaluation, sustained release of silver at bactericidal levels for at least 21 days is observed. Staining of hard and soft tissues due to the released silver is minimal and reversible.