Dental Tribune USA

Pest control in gums gardening: Locally applied antimicrobials as adjuncts to nonsurgical periodontal therapy

By Sandra Pierce, USA
August 13, 2009

Success in gardening depends partially on pest control. The use of chemicals to inhibit pest growth often yields a healthier crop. Periodontal therapy is to gums as pest control is to soil. The focused use of chemotherapeutics as antimicrobials can enhance the outcomes of nonsurgical periodontal therapy, resulting in healthier mouths for our patients. 


The benefits of chemotherapeutics as adjuncts to nonsurgical periodontal therapy have been well established. As a rule, locally applied antimicrobials (LAAs) are used in pockets with 5 mm or greater depths. They can be placed at the time of initial nonsurgical therapy or as a secondary treatment for nonresponsive sites.

As adjunctive nonsurgical therapies have developed during the last 30-plus years, several challenges presented themselves. The antimicrobial products need to be concentrated for an adequate time in the treatment sites in therapeutic doses.

Although there are many antimicrobial mouth rinses, they do not remain at adequate levels of concentration for a therapeutic length of time. LAAs are another alternative.

LAAs are often a better choice than systemic antibiotics in the treatment of periodontal disease. There are fewer risks and side effects, such as upset to the gastrointestinal tract, systemic opportunistic infections, the development of drug resistant bacteria, anaphylactic shock and patient compliance.

Systemic antibitotics are most effective against individual bacteria. When they colonize into a biofilm, the antibiotics must be 250 times more concentrated to be effective.

According to Wilkins (2009), general characteristics of an effective chemotherapeutic agent should include:

  • Nontoxic: the agent does not damage oral tissues or create systemic problems.
  • No, or limited, absorption: the action is confined to the oral cavity.
  • Substantivity: the ability of an agent to be bound to the pellicle and tooth surface and be released over a period of time with retention and potency.
  • Bacterial specificity: may be broad spectrum, but with an affinity for the pathogenic organisms of the oral cavity.
  • Low induced drug resistance: low, or no, development of resistant organisms to the agent.

LAA summaries


Microspheres of minocycline are applied to the pocket in powdered form. As fluid circulates, the minocycline is released over a period of time.


  • Arestin can be costly to apply, especially if it is needed multiple times in multiple sites; there is only one application per cartridge.
  • In the initial study for FDA approval, the product was applied on three occasions. As sales representatives approached clinicians, this fact was not disclosed and clinicians failed to achieve similar results, causing distrust with the product.
  • Patient acceptance went down when second and third treatments were recommended.
  • The cartridges can occasionally be faulty, and may be damaged by the operator.
  • It is necessary to have specific equipment to place (the syringe).


  • Substantivity is very good, and the product can last up to 21 days.
  • The application is convenient. It is quick and easy to place.
  • The product does not require refrigeration, yet it has a good shelf life.
  • It “may block collagenases that are implicated in host tissue breakdown” (Oringer 2002).
  • The applicator is adaptable. The cartridge can be bent to accommodate correct insertion angles. Although the tip is somewhat bulky, it can be modified with pressure from the end of a mirror handle and made flat enough to insert into a pocket.
  • “Patients with advanced periodontal disease, or smokers are two to three times more likely to respond (than to placebo or control),” (Paquette 2004).


Two syringes are combined to create a doxycycline gel that is expressed through the canula. When it comes in contact with sulcular fluids, the gel solidifies. The doxycycline is released over time as the product biodegrades in the pocket.


  • The product has to be mixed chairside 100 times, which can be time consuming. (Some hygienists have their patients mix it while they complete instrumentation, to save time.)
  • The sticky and viscous nature of the gel can cause it to stick to the application canula, and be pulled out as the canula is removed from the pocket. This makes it somewhat technique sensitive.
  • There have been anecdotal reports of the matrix left behind after the doxycycline had dissolved. Those remnants could potentially harbor bacteria if left in the treated site for a prolonged time.
  • An allergic reaction is possible.


  • Good safety record.
  • It is easily placed to the maximum pocket depth due to the small size of the application canula, and its flowability allows it to adapt to root morphology.
  • There have been no reports of resistance to localized applications of doxycycline to date.
  • Lasts up to 21 days (Atridox Web site).
  • Works on smokers just as well as nonsmokers (Ryder 1999).
  • Its “efficacy can increase with retreatment” (Lessem 2004).
  • It has proven applications in peri-implantitis (Renvert 2008).
  • It is cost effective because one syringe can be used in up to six sites.


A flat rectangular chip, similar in appearance to a popcorn hull, the product is placed in a pocket, where it dissolves slowly, releasing chlorhexidine.


  • The product must be refrigerated before placement.
  • Handling the chip becomes more difficult as it warms. The chip loses its rigidity, and becomes difficult to place.
  • The means of delivery prevents taste alterations and tooth staining, compared to chlorhexidine rinses.
  • Because the chip keeps its basic form, it tends to become displaced or lost before the antimicrobial action is complete.
  • The product comes in a shape that is not ideal for all pockets.
  • The chip is too wide for many pockets.
  • The chip does not conform to root morphology, especially in furcations.


  • When the site is ideal, the product is quick to place.
  • No special tools are required to place the chip.
  • It lasts over seven days (per package insert).


With all of these antimicrobial agents available to us, the question can be how to decide which one to use. The answer depends on practice philosophy, availability, cost, efficacy, anatomical considerations, allergies and treatment planning. Some insurance companies won’t pay for periodontal surgery for up to two years after a site has been treated with an LAA.


In gardening, a seed must be planted in the proper soil. It must be watered, nourished and protected from pests. Dental hygienists are caretakers of our patients’ health. With LAA, clinicians can exponentially enhance the benefits of nonsurgical periodontal therapy.

Come garden in the gums with me!

A complete list of references is available from the publisher.

About the author

Sandra Pierce has been a dental hygienist for 14 years, the last 12 of which have been spent in a periodontal practice. She has filled several service roles, most recently as vice president of the Utah Dental Hygienists’ Association. A clinical instructor and associate professor at Utah College of Dental Hygiene, Pierce is known as “The Gums Gardener.” She lectures nationally on nonsurgical periodontal therapies and dental hygiene issues.
You may contact her at:
Tel.: +1 801 372 0430
Web site:

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