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26 Cards in this Set

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  • Back
Mechanical plaque removal
MOST COMMON; physical removal of plaque or plaque retention sites; ie. by tooth-brushing, dental scaling, sealants or cavity preparations
Why Use Non-Mechanical Approaches like chemotherapeutics? (4)
1) pathogenic plaques are frequently in areas which are INACCESSIBLE to mechanical control, ie. pit, fissures, gingival crevices and biofilms, 2) some patients, like the ELDERLY OR DISABLED, cannot achieve proper plaque control, 3) a few diseases such as rampant caries or refractory periodontitis, cannot be managed solely by mechanical means and 4) some diseases are best resolved by eradication of specific pathogens, eg. AGGREGATIBACTER ACTINOMYCETESCOMITANS (Aa) in localized aggressive periodontitis.
Criteria for Ideal Chemotherapeutic Plaque Control Agents (4)
1) SUBSTANTIVITY: Since the mouth has very effective clearing and cleansing mechanisms, antimicrobial agents must be able to ADHERE to oral surfaces long enough to be useful, 2) PLAQUE PENETRATION: Must be able to PENETRATE BIOFILMS to get to pathogens deep within biofilm, 3) LONG-TERM USE: Since most oral diseases are chronic and may require long-term therapy, agents should be acceptable for long term use, eg. good taste and low cost, 4) POSE LOW RISK TO PATIENT: Since oral diseases are usually not life-threatening, the risk to benefit ratio mandates use of LOW-RISK AGENTS.
6 Plaque Control Strategies
1) SYSTEMIC ANTI-MICROBIALS: antibiotics administered when oral infections become systemic, pose a systemic threat, or when the agent is expected to reach an oral site via a systemic route, 2) LOCAL STRONG ANTI-MICROBIALS: SUSTAINED-RELEASE agents or sustained-release devices that can be inserted into periodontal pockets and last for extented periods of time to inhibit plaque-mediated diseases via local eradication of pathogens, 3) KILL ONLY THE PATHOGENS: Inhibits oral diseases while preserving any benefits of the biofilm. Unfortunately, only a few of such methods are available (Ex: xylitol), 4) ECOLOGICAL APPROACHES: does not entail direct removal or killing of bacteria, but in altering their survival activities such as growth rates, metabolism, or pathogenic mechanisms; Ex: reducing dietary sucrose to block proliferation of mutans streptococci (MS), 5) STIMULATE HOST DEFENSES: Ex: stimulate antibodies to pathogens via potential vaccines, 6) BIOLOGICAL METHODS: using living organisms to either inhibit or kill pathogenic species (Ex: probiotics and replacement therapy), 7) BIOFILM STRATEGIES, 8) LOCAL WEAK ANTI-MICROBIALS: Goal is to change the ecology (Ex: Sub-MIC agents)
Oral diseases treated by systemic anti-microbials (5)
1) aggressive periodontitis, 2) refractory periodontitis, 3) NUG, 4) pre- and post-surgical procedures, and 5) acute dental infections hich are treated in this manner are acute dental infections,
Side effects of long-term use of systemic microbials (4)
1) antibiotic-resistant strains, 2) microbial overgrowths, 3) toxicity or allergies or 4) interference with other medications; *For this reason, we MOST COMMONLY USE SHORT-TERM TREATMENT (up to 2 weeks) in both systemic AND local treatments
Resistant strains
genetic variants of indigeneous residents which are not killed or inhibited by the agent.
Microbial overgrowths (and example)
occur when an organism which is naturally not susceptible to the agent, takes advantage of depletion of susceptible competitors in the vicinity and proliferates to a high level. Ex: Candida species (fungi) overgrowths in oral biofilms can occur after broad-spectrum antibiotic therapy since Fungi are not killed by antibiotics but bacteria are.
2 examples of LOCAL strong anti-microbials
1) 10% doxycycline in bioresorbable gels, 2) chlorhexidine in removable plastic strips or fibers
Local strong versus systemic antimicrobials (2)
LOCAL agents have 1) lower risks of systemic side-effects and 2) the ability to use higher doses, which tend to facilitate treatment outcomes and discourage development of resistance.
Disadvantage of local anti-biotics
occasional need to REPLACE dislodged antibiotics or their carrier devices. Agents must remain at oral sites long enough to be effective.
Disadvantage of ANY form of strong antimicrobial (2)
1) Disruption of the beneficial attributes of biofilms, such as colonization resistance, or 2) May kill beneficial bacteria, eg. alkali- or hydrogen peroxide-forming bacteria.
Treatment methods that kill only the target pathogens (3)
1) XYLITOL: sugar alcohol which selectively kills mutans streptococci in oral biofilms. 2) STAMP reagents, 3) Vaccines
Advantage/Disadvantage of using an Ecological approach
Advantage: Since an ecological approach requires only dietary changes or alteration of environmental factors, LOW RISK to the patient is a major advantage; Disadvantage: PATIENT NON-COMPLIANCE is an issue
2 Advantages of stimulating host defenses via vaccines
1) independent of patient compliance, 2) Vaccines would be for specific pathogens, thus preserving beneficial aspects of the indigenous microflora.
Limitations of using vaccines (3)
1) potential risk to patients (For example, a caries vaccine was successful in animals, but since it cross-reacted with heart tissue in vitro, it was never approved for human usage.), 2) poor susceptibility of biofilm inhabitants and 3) incomplete knowledge about vaccine treatment of biofilm-mediated diseases or chronic mixed infections.
Probiotic therapy
Biological method where there is oral implantation of viable and/or genetically altered microorganisms via dietary products like yogurt
Replacement therapy
Introduction of a less virulent organism into a biofilm to take the place of a more virulent one (Biological method)
Example of Replacement therapy
a mutant of Strep. mutans was made DEFICIENT IN LACTIC DEHYDROGENASE (LDH), an enzyme required for lactic acid production. When LDH-negative strains were implanted in rodents before exposure to conventional Strep. mutans, the altered strain occupied the biofilm niche for Strep. mutans and EXCLUDED THE NATURAL STRAIN. Since the mutant strain could not produce sufficient acid for caries, no disease occurred.
Disadvantage of biological methods
Potential adverse risks implanting microorganisms may out-weigh the benefit
Advantage of biological methods/probiotic therapy
It has had some success in animals and humans; Currently finding bio methods for oral diseases is an area of active research
Sub-Minimal Inhibitory Concentration (MIC) Chemotherapeutics
use of weak chemical agents (LOCAL WEAK ANTI-MICROBIAL) to accomplish partial plaque control by ALTERING THE ECOLOGY of pathogenic biofilms.
Benefit of using Sub-MIC
allows preservation of beneficial biofilm functions like colonization resistance and maintenance of protective species
specific ecology hypothesis (SEH)
that specific ecological imbalances determine pathogenic events and can be best addressed by correcting the aberrant ecology (ie. pollution)
Weak versus strong antimicrobials
Weak anti-microbials are advantageous since it preserves some of the beneficial aspects of oral biofilms and can be administered for long periods of time without risk to biofilms or the host; Ex: over-the-counter (OTC) mouthrinses, dentifrices or fluoride
Limitations of weak or sub-MIC agents (3)
1) results are NOT IMMEDIATELY APPARENT, 2) patients are frequently NON-COMPLIANT with provider recommendations and 3) agents are mainly adjunctive to other treatments rather than being definitive (must be used in addition to other treatments to be effective).