Anti-microbial, Antibiotic, Anti-infective: Pharmacological Co-Treatment
Host Factor Modulating Substances
Anti-infectious Supportive Therapy—Antibiotics in Periodontitis Therapy
The accumulation of bacteria upon the teeth represents the primary cause of gingivitis and periodontitis. The regular mechanical removal of plaque biofilm from all non-desquamating surfaces is therefore essential, and it is also the primary measure for prevention or inhibition of the progression of periodontitis (Mombelli 2003).
Through systematic, careful debridement of teeth and affected root surfaces, periodontitis can in many cases be successfully treated. Two disadvantages of this non-specific mechanical treatment, which is repeated regularly at recalls, are the irreversible and ever-increasing damage to tooth hard structure, especially roots within periodontal pockets, as well as gingival recession. In addition, it is virtually impossible to mechanically remove dental plaque from narrow grooves and scratches, narrow furcations and other bacterial reservoirs within the pocket area (p. 255).
Thus it is appropriate to combine mechanical plaque suppression with a medicinal, anti-infectious parallel therapy. Since only a few bacterial species are potentially periodontopathic, it is reasonable to eliminate these groups specifically (Mombelli, Slots, van Winkelhoff). These groups contain bacteria that can colonize cells of the pocket epithelium and thus escape both the host response and mechanical cleaning efforts (A. actinomycetemcomitans, P. gingivalis, S. constellatus; Herrera et al. 2002). This situation can be effectively combated using systemic antibiotics or topically-applied medicaments.
In addition to antimicrobial agents, mainly antibiotics with their well-known side effects and the ever-increasing emergence of resistant microbial stains, more and more new substances are being offered for use in periodontal therapy, especially agents that modulate the host response.
This chapter on “Medications” is arranged as follows:
Decision-making criteria—When to use antibiotics?
Systemic antibiotics for periodontitis therapy
Antibiotics—Bacterial sensitivity and resistance
Systemic versus topical antimicrobial treatment
Topical antimicrobial treatment—Controlled release drugs
Host response—modulating substances
Which Pill is the Correct One?
Decision-Making Criteria—When to Use Antibiotics?
Remember: Periodontitis is an infectious disease, caused by periodontopathic, usually opportunistic microorganisms that are organized within a protective biofilm.
Both non-pathogenic and pathogenic species live every-where in the oral cavity, above all in niches of every sort. They construct a biofilm characterized by close community interrelationships, and exchange metabolic by-products, virulence factors, resistance factors etc. The biofilm protects against the host response as well as against antimicrobial pharmacologic agents (Haffajee et al. 2003).
Even though purely mechanical/instrumental treatment—surgical or non-surgical—will usually very much improve the clinical parameters in most cases, in certain situations an antimicrobial supportive therapy, applied systemically or topically, can improve the treatment outcome (Hung & Douglass 2002, Mombelli 2003).
Antibiotics help to subdue the infection; they do not affect healing. Only the host organism can do this. The sensitivity and the nature of the colonization will determine the choice of an antibiotic.
Tests before treatment define the pathogenic species, above all the presence of Aa and/or Pg, and provide a basis for selecting an antibiotic.
Tests after treatment show whether or not the maker bacteria have been eliminated.
Pooled Findings or Individual Findings?
With the use of systemic antibiotics, pooled findings are sufficient. However, if individual active residual pockets remain after treatment, the pooled findings provide no information about the initial status.
When Indicated: Which Antibiotic to Prescribe?
The spectrum of efficacy of antibiotics, their important side effects and the compliance of the patient must be understood in advance: Oral ingestion (tablets) over an extended period of time demands discipline from an informed patient (Newman & van Winkelhoff 2001).
In general, broad spectrum antibiotics (e.g., tetracyclines) are used only for special indications. While the commensal flora consists primarily of gram-positive aerobes, the periodontopathic organisms are mainly gram-negative and anaerobic.
Antibiotics—Bacterial Sensitivity and Resistance
One of the greatest, world-wide medical problems of the next decades will certainly be bacterial resistance: Antibiotics that have up until now effectively eliminated sensitive bacterial species will no longer have any effect. The spectrum of activity of the well-known antibiotics will become ever smaller, and new antibiotics have not been developed for a very long time. The reason for the increase in bacterial resistance can be found in the careless and widespread use of antibiotics by physicians and in hospitals, but also in the almost grotesque use of antibiotics as growth enhancers in the food industry in certain countries; more than half of all antibiotic production, world-wide, is dedicated to this arena. In addition to naturally occurring resistance, resistance of previously sensitive bacterial species can occur in several ways:
Transfer via plasmids (virulence transfer, p. 35)
Selection via genetic “survival of the fittest”
The latter frequently occurs due to the overuse of antibiotic agents: If the dosage is too low or massively high (only the most pathogenic microbes survive), or if the antibiotic regimen is too short or too long.