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Adjunctive Use of Antibiotics and Antimicrobials in Periodontal Therapy

In conjunction with scaling and root planing, antibiotics and antimicrobials can be effective additions to the periodontal therapy armamentarium.

Scaling and root planing is the most effective and most recommended choice of treatment, as part of nonsurgical periodontal therapy.1,2 However, periodontal treatment can be supported by adjunctive therapies designed to reduce chronic inflammation via local or systemic agents and/or host modulation adjunctive therapies in periodontal diseases.2

Host modulation adjunctive therapy is a treatment that potentially reduces tissue destruction by modifying host response factors.3 The only drug approved by the United States Food and Drug Administration (FDA) is a subantimicrobial dose of doxycycline. It is a systemic drug administered for host modulation as an adjunct to scaling and root planing in the treatment of periodontitis.4 This host modulation adjunctive therapy is a collagenase inhibitor consisting of a 20-mg capsule of doxycycline hyclate for oral systemic administration. Research shows that patients with periodontitis who used this doxycycline regimen daily reduced the elevated collagenase activity in the gingival crevicular fluid.5

The bactericidal metronidazole is effective against anaerobic microorganisms in periodontal diseases. It is used as an adjunctive therapy in gingivitis, necrotizing ulcerative gingivitis, chronic periodontitis, and aggressive periodontitis. As with other adjunctive therapies, metronidazole should be used in combination with scaling and root planing, surgery, or other antibiotics. It is most commonly prescribed in 250 mg tablets and taken three times a day for 7 days. Due to the dosage regimen, patient compliance may be challenging. Haffajee et al6 found that patients with periodontal pockets ≥ 6 mm experienced significant reduction of pocket depths and increases in attachment while using metronidazole. When metronidazole is administered as a combination therapy with amoxicillin, the patient receives diverse action and increases the spectrum of antimicrobial activity. The combination of amoxicillin (250 mg)-metronidazole (75 mg) taken three times daily for 8 days is one of the most common antibiotic combination in periodontics. Berglundh et al7 showed that patients with periodontitis experienced improved periodontal health, reduction of periodontal pathogens, and decreased lesion size with the amoxicillin-metronidazole regimen.

Using systemic antibiotics as an adjunctive therapy to scaling and root planing can provide additional benefits over scaling and root planing alone in the treatment of periodontitis, including clinical attachment loss and pocket depth change, and reduced risk of breakdown of the periodontal structures. However, the use of systemic antibiotic therapy is not a substitute for scaling and root planing procedures or meticulous patient self-care.


Local drug delivery systems are used in periodontal pockets and can inhibit or eliminate periodontal pathogenic microorganisms, as well as modulate the inflammatory response of tissues. However, they do not replace the need for thorough scaling and root planing. Local drug delivery systems are placed into periodontal pockets. The adjunctive use of local drug delivery systems with controlled release properties may provide a defined, but limited beneficial response on periodontal pockets. Furthermore, the success of local drug delivery depends on clinical findings, responses to treatment, desired clinical outcomes, and patients’ dental and medical histories.8 The main advantage is their ability to deliver therapeutic levels of antibacterial agents directly into the periodontal pockets with no systemic side effects. However, the ability to control the release of the drugs at a specific site for a prolonged period is a key factor in their success.9

A gelatin matrix containing 2.5 mg of chlorhexidine gluconate is a controlled-release subgingival delivery system. It is used as an adjunctive therapy in conjunction with instrumentation in periodontal maintenance with pockets ≥ 5 mm that bleed on probing. The chlorhexidine is placed into the periodontal pocket. When it contacts subgingival fluids, it becomes sticky and binds to the epithelium lining in the pocket. Chlorhexidine is released over 7 days to 10 days and the chip resorbs and does not have to be removed. Puri et al9 reported that the use of this system improved periodontal health and reduced the recurrence of periodontal pathogens.

A gel composed of 10% doxycycline hyclate is another option. The solution is mixed in two syringes and injected into the periodontal pocket around the tooth. The solution solidifies on contact with the gingival crevicular fluid. As it biodegrades, doxycycline is delivered to the site at high levels for 7 days to 14 days.10 Deo et al11 found that this therapy reduced pocket depth and increased clinical attachment levels more so than scaling and root planing alone.

A sustained released product contains the antibiotic minocycline hydrochloride, which is a broad spectrum tetracycline antibiotic and one of the most active antibiotics against most of the microorganisms associated with periodontal diseases. It has the most marked substantivity, and is a bio-absorbable sustained local drug delivery system in a disposable polypropylene applicator of 2% minocycline hydrochloride.12 One of its advantages is that the drug can be placed at a higher concentration subgingivally for 24 hours with sustained release. The drug concentration decreases exponentially following a first application.12 The evidence supports that adjunctive locally delivered, controlled-release antimicrobials increase the effectiveness of scaling and root planing.13


Antimicrobial rinses have been shown to be useful adjuncts to daily oral self-care.14 Myriad antimicrobial rinses are available—including those containing cetylpyridinium chloride, chlorine dioxide, chitosan-argininamide, peppermint oil, tea tree oil, lemon peel oil, and aloe vera—but the most research has been conducted on mouthrinses containing chlorhexidine and essential oils. While not an antimicrobial, delmopinol is available in a mouthrinse and is designed to prevent plaque from accumulating. A recent study found that chlorhexidine and essential oil mouthrinses inhibit biofilm proliferation and reduce gingival inflammation compared with a placebo.15 Antimicrobial rinses can provide patients with efficient, safe, and practical means of controlling repopulation of pathogenic bacteria and gingivitis. However, as mouthrinses do not penetrate into deep periodontal sites, their utility in treating periodontitis is limited.

Potential risks of antimicrobial mouthrinse use have been studied. The inclusion of antibacterial ingredients may impact the oral microbes critical for nitric oxide formation, and, in turn, predispose patients to metabolic disorders including diabetes.16 Joshipura et al16 found that twice daily users of antimicrobial mouthrinses experienced an increased risk of prediabetes/type 2 diabetes. However, the study subjects were all overweight/obese and had existing risk factors for diabetes. Additionally, more than 60% of study subjects already had moderate or severe periodontal disease.16 While some studies have shown an increased risk of oral cancer with antimicrobial mouthrinse use,17 a metanalysis found no relationship between mouthrinse and oral cancer, regardless of frequency of use.18


Patients who are periodontally involved or who do not comply with self-care instructions should be educated about antibiotics and antimicrobial rinses as an adjunct to their oral hygiene regimens. Additionally, the relationship between oral health and overall health will illustrate the importance of an interprofessional approach to oral health promotion during patient education. Nutritional counseling, smoking cessation, diabetes risk assessment, and oral cancer screening should be part of patient education. These additional components to self-care instructions may help clinicians determine if antibiotics or antimicrobial rinses will benefit patients. Dental hygienists are qualified to provide overall health promotion and disease prevention education and should not limit their scope to oral health alone.19


Research shows that the use of adjunctive, locally delivered, controlled-release antimicrobials improve the efficacy of scaling and root planing.13 It should be noted that the use of adjunctive procedures to enhance periodontal therapies is not an alternative method for meticulous self-care or periodontal maintenance. Oral health professionals must determine the effectiveness of adjunctive therapies available for treating periodontal diseases based on the needs of individual patients.


  1. Page R. The microbiological case for adjunctive therapy for periodontitis. J Int Acad Periodontol. 2004;6:143–149.
  2. Bader H. Adjunctive periodontal therapy: a review of current techniques.  Available at: Accessed August 27, 2018.
  3. Shinwari M, Tanwir F, Hyder P,  Bin Saeed M. Host modulation therapeutics in periodontics: role as an adjunctive periodontal therapy. J Coll Physicians Surg Pak. 2014;24:676–684.
  4. Caton J, Ryan ME. Clinical studies on the management of periodontal diseases utilizing subantimicrobial dose doxycycline (SDD). Pharmacol Res. 2011;63:114–120.
  5. Golub LM, McNamara TF, Ryan ME, et al. Adjunctive treatment with subantimicrobial doses of doxycycline: effects on gingival fluid collagenase activity and attachment loss in adult periodontitis. J Clin Periodontol. 2001;28:146–156.
  6. Haffajee A, Torresyap G, Socransky S. Clinical changes following four different periodontal therapies for the treatment of chronic periodontitis: 1 year results. J Clin Periodontol. 2007;34:243–253.
  7. Berglundh T, Krok L, Liljenberg B, Westfelt E, Serino G, Lindhe J. The use of metronidazole and amoxicillin in the treatment of advanced periodontal disease. A prospective, controlled clinical trial. J Clin Periodontol.1998;25:354–362.
  8. DaRocha H, Silva C, Santiago F, Martins L, Dias P, DeMahalhães D. Local drug delivery systems in the treatment of periodontitis: a literature review. J Int Acad Periodontol. 2015;17:82–90.
  9. Puri K, Dodwad V, Bhat K, Puri N. Effect of controlled-release Periochip on clinical and microbiological parameters in patients of chronic periodontitis. J Indian Soc Periodontol. 2013:17:605–611.
  10. Mukhatar A, Vandana K. A comparative evaluation of atrigel delivery system (10% doxycycline hyclate) Atridox with scaling and root planing and combination therapy in treatment of periodontitis: A clinical study. J Indian Soc Periodontol. 2012:16:43–48.
  11. Deo V, Ansari S, Mandia S, Bhongade M. Therapeutic efficacy of subgingivally delivered doxycycline hyclate as an adjunct to non-surgical treatment of chronic periodontitis. J Oral Maxillofac Res. 2011;2: e3.
  12. Abbas S, Mahendra J, Ari G. Minocycline ointment as a local drug delivery in the treatment of generalized chronic periodontitis—a clinical study. J Clin Diagn Res. 2016;10:ZC15–ZC19.
  13. Finkelman R, Polson A. Evidence-based considerations for the clinical use of locally delivered, controlled-release antimicrobials in periodontal therapy. J Dent Hyg. 2013;87:249–264.
  14. Moran J, Pal D, Newcombe R, Addy M. Comparison of a phenolic and a 0.2% chlorhexidine mouthwash on the development of plaque and gingivitis. Clin Prevent Dent. 1991;13:31–35.
  15. Goutham BS, Manchanda K, Sarkar AD, Prakash R, Jha K, Mohammed S. Efficacy of two commercially available oral rinses—chlorohexidine and Listerine on plaque and gingivitis—a comparative study. J Int Oral Health. 2013;5:56–61.
  16. Joshipura K, Muñoz-Torres F, Morou-Bermudez E, Patel, R. Over-the-counter mouthwash use and risk of pre-diabetes/diabetes. Nitric Oxide. 2017;71:1420.
  17. Eliot MN, Michaud DS, Langevin SM, McClean MD, Kelsey KT. Periodontal disease and mouthwash use are risk factors for head and neck squamous cell carcinoma. Cancer Causes Control. 2013;24:1315–1322.
  18. Gandini S, Negri E, Boffetta P, La Vecchia C, Boyle P. Mouthwash and oral cancer risk quantitative meta-analysis of epidemiologic studies. Ann Agric Environ Med. 2012;19:173–180.
  19. Ohrn K. The role of dental hygienists in oral health prevention. Oral Health Prev Dent. 2004;2(Suppl 1):277–281.

From Dimensions of Dental HygieneSeptember 2018;16(9):18,20.

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