Strategies and agents in supragingivalin chemical plaque control MICHEL BRECX Periodontology 2000, Vol. 15 5조 1번 고상훈
Mechanisms of supragingival dental plaque formation• Early human dental plaque formation is initiated by the deposition of a thin biofilm mainly derived from salivary glycoproteins onto the tooth surface• Plaque formation cannot be stopped, but its accumulation does not cause any harm if the surface coating on the teeth is devoid of bacteria
Mechanisms of supragingival dental plaque formation• When one or two layers of bacteria are present on the tooth surface in a healthy individual, the subject’s immune system can cope with these microorganisms, and the subject can thus present a healthy gingiva• Therefore, disturbing plaque accumulation is of major importance
Mechanisms of supragingival dental plaque formation
Chemical plaque control• The present meaning of dental plaque control includes only the supragingival and marginal areas because mouthwashes used under normal conditions do not reach the subgingival area• The most tested and effective antiplaque agent known today is chlorhexidine
Chemical plaque control• The mode of action of chlorhexidine against bacteria is well understood and is concentration dependent.• Chlorhexidine acts on the cell wall of the microorganisms by changing their surface structures. Osmotic equilibrium is lost and, as a consequence, cytoplasmic membrane is extruded, vesicles are formed and the cytoplasm precipitates• Because chlorhexidine has been shown to be able to break up existing dental plaque, it can really be considered as a potent antibacterial agent, bactericidal at high concentration and bacteriostatic at lower concentration, such as when gradually diluted in saliva over time.
Chemical plaque control• Many substances have some degree of antimicrobial efficacy, especially in vitro, but it is totally impractical to ask everybody to rinse his or her mouth ten times a day, because the solution is completely devoid of substantivity, and rapidly diluted by and swallowed with saliva.• The agents that do not exhibit any significant substantivity (only minutes) were categorized as first-generation antimicrobial agents.
Chemical plaque control• Second-generation antimicrobial agents are characterized by high substantivity, that is, retention of 25-30% after each 1-minute mouthrinse. Such compounds remain active in situ for hours• Substances with mild antibacterial effect but that interfere with bacterial adhesion are referred to as third-generation antimicrobial agents• A fourth generation could be envisaged
Strategies for dental plaque control• When a mouthwash can reduce plaque development by keeping down the numbers of viable bacteria, chemotherapeutic as well as salivary compounds may act synergistically.• Therefore, the combination of mechanical and chemical oral hygiene offers the greatest efficacy, because the bulk of plaque is reduced mechanically, leaving behind only disorganized and thin dental plaque that can easily be further reduced by chemical means.