Nellie and Antimicrobials

March 1, 2013
My dog, Nellie, is a piece of work. She's 17 pounds, all dachshund and a real couch potato. This winter, she's spent many hours hibernating ...

by Lynne Slim, RDH, BSDH, MSDH

My dog, Nellie, is a piece of work. She's 17 pounds, all dachshund and a real couch potato. This winter, she's spent many hours hibernating under the dining room table and scratching. Finally, I became so frustrated with the endless scratching noise, including the jingling collar tags, that I called the vet. To my surprise, my vet found canine pyoderma and prescribed a systemic antimicrobial. Because of my nerdy disposition, I immediately went online and snooped around on PubMed. In searching the literature on this site, I typed in three search terms: systematic review, canine pyoderma, and antimicrobial. Up popped a 2012 systematic review on the effectiveness of systemic antimicrobial treatment in canine superficial and deep pyoderma.

Now that Nellie's settled down and back to chewing her dental bones instead of her skin, I've decided to explore the effects of antimicrobials as adjuncts to subgingival debridement, compared to subgingival debridement alone, in the treatment of chronic periodontitis. I focused on local delivery antimicrobials only. Out comes my iPad and I type in: systematic review, periodontitis, and local antimicrobial. I'm in luck again; up pops a 2012 systematic review on this topic. I read the abstract and then find a way to obtain a pdf of the entire review that is not yet published. I search again for other systematic reviews and find two others, one from 2003 and another from 2005.

I've applied various local antimicrobials and I've used them mostly for localized pocketing in unresponsive sites that were treated initially with mechanical debridement. Indications for use vary depending on clinician-decision making/ expertise, cost-benefit analysis, and the patient's value system. Mechanical debridement is challenging for most clinicians, especially for those of us who work blind. My colleagues who work in a subgingival environment that is visualized by Perioscopy have a definite advantage because they can see and then remove subgingival burnished calculus. Bleeding, unresponsive sites following debridement need to be evaluated by a periodontist.

Even the best clinicians struggle to access deep pockets, furcations, and other inaccessible areas. Adjunctive systemic antimicrobials may improve clinical outcomes and culture/sensitivity tests are useful in cases that do not respond to conventional periodontal therapy, but there are no consensus or evidence-based clinical guidelines for their use.

An advantage of using a local antimicrobial to support mechanical treatment in reducing the number of bacteria is not having to worry about antibiotic resistance or adverse effects and patient compliance issues.1

Systematic reviews from 2003 (Hanes & Purvis) and 2005 (Bonito, et al.) have demonstrated a beneficial effect on the adjunctive use of local antimicrobials when compared to SRP alone, but the clinical magnitude of the effect was limited, which raises the question of efficacy.1,2 Additional periodontal disease reduction ranged from 0.06 mm to 0.51 mm and additional clinical attachment gains ranged from -0.40 mm to 0.39 mm by local delivery of antimicrobials (LDA) as an adjunct to SRP.1

I spent a lot of time reading and studying the 2012 systematic review.3 The Pico question was as follows: "What are the effects of local antimicrobials as adjuncts to subgingival debridement compared to subgingival debridement alone or plus placebo, in chronic periodontitis patients, in terms of clinical outcomes?" The systematic search began with 1,431 references and, after evaluation of titles and abstracts, 1218 were discarded. Only 213 studies remained for evaluation, which provided 52 different studies with only 41 of these included in the meta-analysis. (A meta-analysis is a statistical technique that is used to assess clinical effectiveness of health-care interventions and can give a precise estimate of treatment effect. It combines data from two or more randomized control trials.)

Combining all antimicrobial products, the meta-analysis demonstrated significant probing depth (PPD) reduction (0.407 mm) and clinical attachment (CAL) gain (0.310 mm), and these results were similar to the previous systematic reviews (Hanes/Purvis and Bonito, et al.). The largest effect in PPD was found with the application of tetracycline fibers (which are no longer available in the United States), followed by doxycycline (0.573 mm), and minocycline (0.472 mm). The effects of chlorhexidine chips rendered minimal additional PPD reduction, below 0.4 mm.

Researchers found that different effects by different local compounds depend not only on pharmacology, but on pharmacodynamics of the vehicle employed that are responsible for sustained release. For example, in analyzing the results of three different chlorhexidine formulations, the biggest effect was found for chlorhexidine plus xanthan gel (not used in United States), chlorhexidine chips, and then chlorhexidine varnish, reflecting the ability of the vehicle to sustain the release of the antimicrobial.

Studies in the systemtic reviews with initially deeper PPDs showed a higher magnitude of effect (PPDs up to 2.3 mm), but this enhanced effect also occurred at the control sites. Adverse side effects were minimal. All studies, except two, were described as having a high risk of bias due to the lack of reporting some key study methodology deficiencies. In addition, authors also reported a high degree of heterogeneity in data for most outcome variables, which can overestimate or underestimate the real effect of the tested products, and this can limit the results of this particular systematic review.

The scientific evidence in this systematic review supports the adjunctive use of local antimicrobials to SRP in deep or recurrent periodontal sites, mostly when the vehicle has shown pharmacodynamic properties that assure the sustained release of the antimicrobial. The authors also warn that the evidence must be interpreted with caution because the reported data were highly heterogeneous and most of the studies were categorized with a high degree of bias. Furthermore, clinical trials with strict methodological criteria in future are strongly recommended.

So, after reviewing this new systematic review, what's the "Lynne Slim" takeaway? Having read this systematic review and the two previous ones, there is evidence to support the judicious use of local, sustained release antimicrobials as an adjunct to nonsurgical periodontal therapy. There isn't, however, strong evidence or consensus to support specific clinical protocols and guidelines for local antimicrobial products. It definitely appears that we should not use local antimicrobials indiscriminately and we should also carefully weigh cost/benefit. We should learn Perioscopy and refer to a periodontist for unresponsive bleeding pockets. We should all read the three systematic reviews (references below) and make better, informed patient care decisions. RDH


1. Hanes PJ, Purvis JP. Local anti-infective therapy: pharmacological agents. A systematic review. Ann Periodontol. 2003 Dec; 8(1): 79-98.
2. Bonito AJ, Lux L, Lohr KN. Impact of local adjuncts to scaling and root planing in periodontal disease therapy: a systematic review. J Periodontol. 2005 Aug; 76(8): 1227-36.
3. Matesanz-Perez P et al. A systematic review on the effects of local antimicrobials as adjuncts to subgingival debridement, compared to subgingival debridement alone, in the treatment of chronic periodontitis. J Clin Periodontol. Accepted for publication 2012 (in press).

LYNNE SLIM, RDH, BSDH, MSDH, is an awardwinning writer who has published extensively in dental/dental hygiene journals. Lynne is the CEO of Perio C Dent, a dental practice management company that specializes in the incorporation of conservative periodontal therapy into the hygiene department of dental practices. Lynne is also the owner and moderator of the periotherapist yahoo group: Lynne speaks on the topic of conservative periodontal therapy and other dental hygiene-related topics. She can be reached at [email protected] or

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