Chemotherapeutics

Question 1

What is the rationale behind using mechanical debridement

Answer 1

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

Question 2

What are the limitations of mechanical debridement

Answer 2

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

Question 3

How deep can hand instrument clean?

Answer 3

3.73-4mm

Question 4

What is the rationale for chemotherapeutics

Pavicic at al 1992, Hanes and Purvis 2003

Answer 4

Eliminate specific periopathogens, eliminate periopathogens in areas unreachable by conventional scrp, module host immune response to bacteria ie decrease self destruction, treat mixed infection

Question 5

What is the desired microbiological endpoint

Answer 5

≤4.2% of red complex species

≥15.1% of actinomyces

Question 6

What are the key desired treatment outcomes

Answer 6

Oral environment that promotes health

Complete ecological shift in oral environment

Tooth retention

Achieve stability or reduce disease recurrence

Question 7

Antibiotic vs antiseptic

Answer 7

Antibiotics inhibit/kill selective bacteria

Antiseptic inhibit/destroy microorganisms, not just bacteria

Question 8

Mechanism of triclosan

Answer 8

Disrupt cytoplasmic membrane in bacterial cell (anti bacterial)

Anti inflammatory eg suppress acute and chronic mediators of inflammation

Question 9

Which anti plaque agent has greatest % plaque reduction

Answer 9

Chlorhexidine 80%

Question 10

Draw back of mouth rinses

Answer 10

Unpredictable penetration of pocket by against

Insufficient substantivity to allow or proper penetration of agent

Question 11

Mechanism of chlorhexidine

Answer 11

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

Question 12

Side effects of chlor hex

Answer 12

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

Question 13

Systemic review by Cosyn and wyn 2006 showed what about chlorhexidine clinical efficiency

Answer 13

Limited effect unless dont routinely

Question 14

Mechanism of listerine

Answer 14

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

Question 15

Effectiveness of listerine

Answer 15

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%

Question 16

Chx vs listerine efficacy

Answer 16

Van Leeuwen et al 2011
CHX better at reading plaque accumulation 80% vs 50% plaque reduction but no difference in controlling gingival inflammation

Question 17

What is the goal of supragingival irrigation

Answer 17

Flush away bacteria coronal to the gingival margin to reduce existing gingival inflammation and minimise development of gingivitis

Question 18

Metronidazole is a good systemic antibiotic for perio because

Answer 18

Kills off gram negative and red complex ie target periopathogens

Question 19

How are antimicrobial agents used in treatment plan

Answer 19

Adjunctive to mechanical debridement

Antibiotic prophylaxis

Acute perio infections eg anug, abscess with fever and swelling

Systemic manifestation of oral infection

Question 20

Adult dosage of metronidazole AAP position paper slots 2004

Answer 20

500mg tid 8 days

Question 21

Efficacy of systemic microbial

Answer 21

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

Question 22

What does perio stat (doxycycline hyclate) do

Answer 22

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

Question 23

Contraindications for use of locally delivered antibiotics

Answer 23

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

Question 24

Efficacy of locally delivered antibiotics

Answer 24

Bonito et al 2005

Less than 1mm reduction in ppd, clinical outcome not clinically meaningful. Added cost and effort not justifiable

Question 25

Disadvantage of full mouth debridement

Answer 25

Uncomfortable for patient as need LA on every tooth

Do not get chance to check wound healing, less reinforcement of OHI

Question 26

What is the full mouth disinfection theory

Answer 26

Believes that bacteria is also on the tongue and cheek mucosa. Bickler et al 2004: intraoral niches eg tongue, tonsils can act as reservoir for perio pathogens. Translocation of pathogens from non dental sites or untreated pockets may occur before less pathogenic ecosystem is established

Question 27

What are the benefits of full mouth disinfection

Answer 27

Greenstein 2002, scoransky and haffahee 2002

Reduce treatment time
Reduce cost of therapy because supposed to increase clinical attachment and improve treatment outcome
Reduce reservoir of potentially pathogenic micro organisms hence lowering risk of disease recurrence in susceptible patients

Question 28

When should cheotherapeutics be used

Answer 28

Dexterity issues

Post op

Ab prophy

Adjunct for severe perio

Compromised maintenance

Question 29

Dosing regimen for acute periodontal abscessess

Answer 29

Amoxicillin
Azithromycin
Clindamycin