Chemotherapeutics Flashcards
What is the rationale behind using mechanical debridement
Physically disrupt the biofilm
Reduce bacterial load
Remove factors that facilitate biofilm formation eg calculus is plaque retentive
Delay repopulation of pathogenic microbes in gingival pockets
What are the limitations of mechanical debridement
Patient factors
Site factors
Clinical factors
(PSC!!)
Patient: attitude, dexterity, smoking habits, health eg diabetes
Site factors:
Pocket depth — instrument clean up to 3.73-4mm
Anatomy eg cementicles, root concavities
Restorations eg overhangs
Clinician: meticulousness, skill
How deep can hand instrument clean?
3.73-4mm
What is the rationale for chemotherapeutics
Pavicic at al 1992, Hanes and Purvis 2003
Eliminate specific periopathogens, eliminate periopathogens in areas unreachable by conventional scrp, module host immune response to bacteria ie decrease self destruction, treat mixed infection
What is the desired microbiological endpoint
≤4.2% of red complex species
≥15.1% of actinomyces
What are the key desired treatment outcomes
Oral environment that promotes health
Complete ecological shift in oral environment
Tooth retention
Achieve stability or reduce disease recurrence
Antibiotic vs antiseptic
Antibiotics inhibit/kill selective bacteria
Antiseptic inhibit/destroy microorganisms, not just bacteria
Mechanism of triclosan
Disrupt cytoplasmic membrane in bacterial cell (anti bacterial)
Anti inflammatory eg suppress acute and chronic mediators of inflammation
Which anti plaque agent has greatest % plaque reduction
Chlorhexidine 80%
Draw back of mouth rinses
Unpredictable penetration of pocket by against
Insufficient substantivity to allow or proper penetration of agent
Mechanism of chlorhexidine
Positively charged cationic bisguanide that absorbs to negatively charged cites
Bacteriostatic in low concentration, bacericidal in high concentration
Bonesvall et al 1974
- bind to cell wall, destabilise and rupture
- disrupt osmotic barrier —> coagulate intracellular content, cytoplasmic membrane extrusion
- substantivity ie prolonged association; chx bound to salivary proteins released in active form in 8-12 hours
Side effects of chlor hex
Staining of teeth, tongue, restorations
Desquamation of oral mucosa
Parotid swelling
Altered taste sensation to become bitter
More calculus formation because seem to promote mineral uptake into biofilm
Systemic review by Cosyn and wyn 2006 showed what about chlorhexidine clinical efficiency
Limited effect unless dont routinely
Mechanism of listerine
Ouhayoun 2003
Rupture cell walls of microorganisms and inhibit enzymatic activity
Extract endotoxins from gram negative pathogens
Bactericidal effect
Prevent aggregation of commensal bacteria with pathogens
Slow down bacteria multiplication
Effectiveness of listerine
Cochrane systemic review found that listerine able to reduce plaque by 54% and marginal bleeding by 34% in peri implant tissues
Charles et al 2011: after rinsing twice daily for 14 days, reduction in total anaerobes by 66-79%
Chx vs listerine efficacy
Van Leeuwen et al 2011
CHX better at reading plaque accumulation 80% vs 50% plaque reduction but no difference in controlling gingival inflammation
What is the goal of supragingival irrigation
Flush away bacteria coronal to the gingival margin to reduce existing gingival inflammation and minimise development of gingivitis
Metronidazole is a good systemic antibiotic for perio because
Kills off gram negative and red complex ie target periopathogens
How are antimicrobial agents used in treatment plan
Adjunctive to mechanical debridement
Antibiotic prophylaxis
Acute perio infections eg anug, abscess with fever and swelling
Systemic manifestation of oral infection
Adult dosage of metronidazole AAP position paper slots 2004
500mg tid 8 days
Efficacy of systemic microbial
Evidence indicates that systemic antibiotics do not offer sufficient benefit to overcome risks such as drug sensitivity, emergence of antibiotic resistant pathogens to treat common forms of adult periodontitis
Severe uncommon forms may require systemic ab + scrp + chx to reduce bacterial load
What does perio stat (doxycycline hyclate) do
Anticollagenase activity. Inhibits MMP and decreases connective tissue breakdown Canon et al 2000
No data regarding treatment outcome > 12 months
Significant CAL and PD reduction when used as adjunct to ScRP preshaw et al 2004
Contraindications for use of locally delivered antibiotics
Multiple sites with ppd ≥5mm in same quadrant (should be used for ISOLATED pockets of moderate disease that have not responded to scrp alone)
Anatomical defects present eg intrabony defect
Efficacy of locally delivered antibiotics
Bonito et al 2005
Less than 1mm reduction in ppd, clinical outcome not clinically meaningful. Added cost and effort not justifiable
