Arestin remains active in your periodontal pockets for at least 14 days after placement, slowly releasing the antibiotic minocycline directly into the gum tissue. The microspheres themselves are bioresorbable, meaning they dissolve on their own and don’t need to be removed. While the active drug release lasts about two weeks, the clinical benefits of the treatment persist for months.
How Arestin Works in Your Gums
Each unit-dose cartridge contains just 1 mg of minocycline, a tiny amount of antibiotic packed into microscopic polymer spheres. Your dentist places these microspheres directly into the infected periodontal pocket, usually right after a scaling and root planing (deep cleaning) procedure. Once in the pocket, the spheres slowly break down and release minocycline over time, maintaining bacteria-killing concentrations right where the infection lives.
This local delivery system is remarkably efficient. Minocycline concentrations in your saliva and gum fluid near the treated site reach levels roughly 1,000 times higher than what shows up in your bloodstream. That means the drug is overwhelmingly concentrated at the infection site rather than circulating through the rest of your body. The amount that does reach your bloodstream is two to three times lower than what you’d absorb from taking the same dose of minocycline as an oral pill.
The 14-Day Active Release Window
The microspheres are designed to release minocycline at concentrations high enough to kill periodontal bacteria for at least 14 days. During this window, the antibiotic maintains levels above 1 microgram per milliliter in the gum fluid, which is the threshold needed to be effective against the bacteria that cause gum disease.
The polymer the microspheres are made from (a material called PGLA, commonly used in dissolvable surgical sutures) gradually breaks down through natural processes in the body. You won’t feel the microspheres dissolve, and there’s nothing left behind to remove. The breakdown products are absorbed harmlessly by surrounding tissue.
Why You Can’t Floss for 10 Days
Because the microspheres need to stay in place to do their job, you’ll be told to avoid floss, toothpicks, and any interproximal cleaning devices around the treated sites for 10 days. Disrupting the area too early can physically dislodge the microspheres before they’ve finished releasing their medication. You can still brush other areas of your mouth normally, but be gentle around treated pockets during that window.
Hard, crunchy, or sticky foods near the treated area are also worth avoiding in the first several days. The goal is to let the microspheres sit undisturbed while they do their work.
How Long the Benefits Last
While the drug itself is active for about two weeks, the improvements it creates last much longer. In clinical trials, patients who received Arestin along with scaling and root planing showed statistically significant reductions in pocket depth that persisted at 9 months. The combined treatment reduced pocket depth by an average of 1.42 mm, compared to 1.18 mm for deep cleaning alone. That difference held steady throughout the study period.
This makes sense when you consider what the antibiotic is doing. By knocking back the bacterial population in the pocket during that critical 14-day window after deep cleaning, Arestin gives your gum tissue a better chance to heal and reattach. The drug leaves your system relatively quickly, but the healing it supports continues for months.
Minimal Impact on the Rest of Your Body
If you’re wondering whether Arestin will affect you systemically the way an oral antibiotic would, the answer is: far less. The 1 mg dose is extremely small compared to typical oral minocycline prescriptions, and the local delivery means most of the drug stays in the gum pocket. Blood levels of minocycline after Arestin placement are significantly lower than what you’d see from swallowing the same amount.
That said, minocycline is still a tetracycline-class antibiotic, so the same general precautions apply. If you have a known allergy to tetracyclines, Arestin isn’t appropriate for you. For most people, though, the systemic exposure is minimal enough that side effects are uncommon compared to oral antibiotics.