Systemic Antibiotics in Periodontal Therapy


The disease affecting the periodontium is of multi-factorial origin. In fact bacteria, local and systemic factors, as well as the host, play a major role in the onset and progression of periodontal disease. Therefore, it would be rationale to use a treatment approach that targets all of these components, including: removal of local (calculus) and systemic factors (host mediation), education of the patient, and reduction (theoretically elimination) of the bacterial flora using chemical agents. However, the use of antibiotics in the treatment of periodontal disease is not that widespread (at least not for the treatment of its chronic form). Several reasons support this decision, such as: cost, bacterial resistance, lack of strong scientific evidence, as well as the problem of establishing the cut-off point: for which case do I give antibiotics and for which cases I rely on other forms of treatment? In my opinion:

The most crucial part of periodontal therapy remains patient motivation and education, as well as removal of calculus.

This, in fact, is the guarantee that treatment will be effective on the long-term. However, I can not deny that after reading the current body of evidence on antibiotics as supplement to the treatment of periodontal disease, I noticed a growing body of scientific evidence supporting the combination of non-specific therapy (Scaling and Root Planing and Oral Hygiene Instructions) with systemic antibiotics.

Antibiotics can be used during different phases of the periodontal treatment: before starting any therapy at all; during initial therapy (SRP and OHI); after initial therapy but before surgery; after surgical therapy; or during maintenance. Moreover, antibiotics can be used with different delivery systems: either local or systemic. In this post I will mostly summarize the indications of systemic antibiotics during initial therapy and the indications of local antibiotics during maintenance therapy.

Photomicrograph of Streptococcus bacteria. (SEM with colorization)

Rationale of Antibiotics Therapy for the Treatment of Periodontal Disease

The use of antibiotics for the treatment of periodontal disease is something not new, and the first studies were conducted in the 80’s (Slots et al 1983, Golub et al 1983, Novak et al 1988). The rationale for their use originates from several factors: periodontal disease is of bacterial origin (Sockransky et al 1987); we are unable to completely detoxify root surface (Mombelli et al 2000, Cobb 2002); last but not least, bacteria can penetrate the epithelium and connective tissue (these are the two components of gum tissue) and be out of our reach (Slots and Rosling 1983). Moreover, certain form of periodontal disease, such as the aggressive periodontal disease (formerly called juvenile, or early on-set) have been associated with a peculiar bacterial flora (Aggregatibacter actinomycetemcomitans, or simply AA) or altered host factors (Armitage et al 2010).

If periodontal disease is in fact caused by a limited number of bacterial species, then non-specific removal of plaque and calculus is not the only form of prevention and treatment.

Treatment of periodontal disease exclusively with antibiotics

Only a few studies have been published assessing the effect of antibiotics alone (or almost alone) on periodontal disease. Novak (Novak et al 1987) described the treatment of 4 patients using tetracycline (1gr/day per os) for 3 to 6 weeks, and meticulous supragingival plaque control (recall every 2 weeks). He reported a clinically and statistically significant improvement of the clinical scenario, with a considerable reduction of probing depth. However, one study is not enough to support the use of this modality of treatment. Therefore treatment of periodontal disease with antibiotics alone is not an acceptable.

Photomicrograph of Porphyromonas Gingivalis.

Treatment of aggressive periodontal disease with systemic antibiotics

Beside the previously mentioned study (Novak et al 1987), that almost exclusively relied on systemic antibiotics, Slots and colleagues (Slots and Rosling 1983) described the clinical and microbiological changes of patient diagnosed with juvenile form of periodontal disease (today would be classified as aggressive) treated with non-surgical and chemical (Betadine and antibiotic) therapies. The antibiotic used was tetracycline (1gr/day per os) for 2 weeks. The composition of microbial flora was altered by scaling and root planing, but not excessively. Betadine did not have any apparent effects on the flora, while tetracycline eliminated AA, although the total elimination occurred after 2 weeks and not earlier. Therefore the authors recommend to prescribe tetracycline for at least 3 weeks. It is also interesting to mention that AA recolonized the majority of the pockets during the study period (1 year). More recently, Guerrero (Guerrero et al 2005) evaluated, in a RCT, the benefit of adjunctive antibiotic therapy for the non-surgical treatment of generalized aggressive periodontal disease. The antibiotic used was a combination of amoxicillin and metronidazole (1.5gr and 1.5gr/day per os) for 7 days. Patients were treated according to the full mouth disinfection protocol (Quirynen et al 1995), half of them were assigned to the antibiotic treatment. The results of this study showed:

There is a beneficial effect of supplementation with antibiotics. This was particularly true for pockets >7mm.

Treatment of chronic periodontal disease with systemic antibiotics

Antibiotics have been used extensively for the treatment of chronic periodontitis (Haffajee et al 2003). They appear to be the most effective when used in combination with SRP instead of stand-alone therapy. The conclusion of Haffajee meta-analysis is that most of the antibiotics appear to be similar in efficacy (slightly favoring tetracycline and metronidazole compared to amoxicillin + metronidazole). In a very recent study, Cionca (Cionca et al 2010) used a combination of amoxicillin and metronidazole (1125mg and 1500mg/day per os for 1wk). The results confirmed the efficiency of supplementing non-surgical therapy with antibiotics to reduce probing depth. Moreover the author wanted to find correlation between bacterial profile of the pockets and outcome of the antibiotic therapy. However, the quantity and quality of bacteria present in the pocket before antibiotic treatment was not correlated with the outcome of the therapy. The findings of this study would support the widespread use of antibiotics, however other studies contradict these findings. In fact Winkel (Winkel et al 2001), using a similar antibiotic combinations (amoxicillin + metronidazole, 1125mg + 750mg/day per os for 1wk) found a correlation between clinical outcome and presence of P. Gingivalis. In conclusion the use of antibiotics as a supplement for the treatment of chronic periodontitis seems justified.

I would consider to supplement with antibiotics the non-surgical therapy of all the patients diagnosed with aggressive periodontitis

(unless contraindicated by allergies or other medical reasons). I also consider antibiotics for the patients diagnosed with moderate to advanced chronic periodontitis. In cases in which a regenerative surgery is needed and I know that a defect will be residual after initial therapy, the patient will receive antibiotics in the post-surgical period.


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