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62 Cards in this Set
- Front
- Back
Define " Sterilization"
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Killing or removing all forms of
microbial life (including endospores) in a material or an object. Heating is the most commonly used method of sterilization. ( endospores) |
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define " Disinfection:"
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Reducing the number of pathogenic
microorganisms to the point where they no longer cause diseases. Usually involves the removal of non-endospore forming pathogens. Disinfection: May use physical or chemical methods: -Disinfectant: Applied to inanimate objects (surfaces or instruments). -Antiseptic: Applied to skin or living tissue. - Degerming: Mechanical removal of most microbes in a limited area. Example: Alcohol swab on skin. |
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Aseptic techniques
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are used to prevent
contamination of : 1)surgical instruments, 2)medical personnel, and 3)the patient during surgery. 4)Aseptic techniques are also used to prevent bacterial contamination in food industry |
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define " Bacteriostatic Agent"
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An agent that inhibits
the growth of bacteria, but does not necessarily kill them. (Suffix stasis: To stop or steady) |
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define " Germicide:"
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An agent that kills certain
microorganisms. Bactericide: An agent that kills bacteria. Viricide: An agent that inactivates viruses. Fungicide: An agent that kills fungi. Sporicide: An agent that kills bacterial endospores of fungal spores. |
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Coal tar distillation
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• Complex mixture of aromatic
compounds • These are first separated by distillation • Phenol is found in the carbolic oil and is recovered by further distillation and washing with slaked lime (calcium hydroxide) solution • Nowadays phenol is produced by chemical synthesis. |
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Antiseptics & Disinfectants
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1. Phenols and Phenolics: ( Phenol, Cresols, Biphenols )
2. Halogens: ( Iodine, Chlorine, 3. Alcohols: (Ethanol, Isopropanol: 4. Heavy Metals: (copper, selenium, mercury, silver, and zinc) 5. Quaternary Ammonium Compounds 6. Aldehydes: (Formaldehyde, Glutaraldehyde) 7. Gaseous Sterilizers: (Ethylene Oxide) 8. Peroxygens (Oxidizing Agents): (Ozone, Hydrogen Peroxide, Benzoyl Peroxide, Peracetic Acid) |
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1-Phenols and ....
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Phenol (carbolic acid):
- Rarely used today because it is a skin irritant (caustic ) and has strong odor. -Acts as local anesthetic. - aromatic alcohol |
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1-and Phenolics:
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Phenolics (derivatives of phenol)
-Cresols (methyl phenol ): Derived from coal tar. - Biphenols : Effective against gram-positive staphylococci and streptococci. Excessive use in infants may cause neurological damage. |
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Phenols and Phenolics:
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Destroy plasma membranes and denature proteins
(detergent effect). Advantages: 1)Stable, 2) persist for long times after applied, and remain active in the presence of organic compounds. |
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Limitations of Phenol
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• Phenol is a caustic substance and reacts with
tissue causing damage. • The maximum concentration permitted in registered preparations is 1% • At these concentrations, phenol acts as a bacteriostat |
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2. Halogens:
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Effective alone or in compounds
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Halogens --> A. Iodine
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-Tincture of iodine (alcohol solution) was one of first
antiseptics used. -Combines with amino acid tyrosine in proteins and denatures proteins. - Stains skin and tissues, somewhat irritating. -Iodophors: Compounds with iodine that are slow releasing, take several minutes to act -Used as skin antiseptic in surgery -Not effective against bacterial endospores. Betadine Isodine ( the above is for iodine ) |
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Halogens --> B. Chlorine
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When mixed in water forms hypochlorous acid:
Cl2 + H2O ------> H+ + Cl- + HOCl -Used to disinfect drinking water, pools, and sewage. - Chlorine is easily inactivated by organic materials. - Sodium hypochlorite (NaOCl): Is active ingredient of bleach. - Chloramines: (chlorine and ammonia) Less effective as germicides. |
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3. Alcohols
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Bacteria, fungi, but not endospores or naked
viruses. Act by denaturing proteins and disrupting cell membranes. Used to mechanically wipe microbes off skin before injections or blood drawing. Not for open wounds, (protein coagulation) -Ethanol: Optimum concentration is 70%. - Isopropanol: Rubbing alcohol Better disinfectant than ethanol (cost and less volatile.) |
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4.Heavy Metals
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Include copper, selenium, mercury, silver, and zinc.
Oligodynamic action: Very tiny amounts are effective. |
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Heavy Metals --> silver
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1% silver nitrate used to protect infants against
gonorrheal eye infections until recently. |
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Heavy metals --> Mercury
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Organic mercury compounds like merthiolate and
mercurochrome are used to disinfect skin wounds. |
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Heavy Metals --> Copper
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Copper sulfate is used to kill algae in pools and fish
tanks. |
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Heavy metals --> Selenium
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Used for fungal infections.
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heavy metals --> Zinc
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Zinc chloride is used in mouthwashes.
Zinc oxide is used as antifungal agent in paints. |
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5. Quaternary Ammonium Compounds:
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Widely used surface active agents.
Cationic (positively charge) detergents. Effective against gram positive bacteria, less effective against gram-negative bacteria. Also destroy fungi, and enveloped viruses. |
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Quaternary Ammonium Compounds examples
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Zephiran in lab spray bottles.
Pseudomonas strains that are resistant and can grow in presence of Quats are a big concern in hospitals Advantages: Strong antimicrobial action, colorless, odorless, tasteless, stable, and nontoxic. Diasadvantages: 1)Form foam. Organic matter interferes with effectiveness. 2)Neutralized by soaps and anionic detergents. |
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6. Aldehydes:
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Include some of the most effective antimicrobials.
Inactivate proteins by forming covalent crosslinks with several functional groups. |
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Aldehydyes --> A. Formaldehyde gas:
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Excellent disinfectant.
Commonly used as formalin, a 37% aqueous solution. Formalin was used extensively to preserve biological specimens and inactivate viruses and bacteria in vaccines. Irritates mucous membranes, strong odor. |
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Aldehydes --> B. Glutaraldehyde:
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Less irritating and more effective than formaldehyde.
One of the few chemical disinfectants that is a sterilizing agent. A 2% solution of glutaraldehyde is: -Bactericidal, tuberculocidal, and viricidal in 10 minutes Sporicidal in 3 to 10 hours Commonly used to disinfect hospital instruments |
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7.Gaseous Sterilizers:
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Chemicals that sterilize in a chamber similar to an
autoclave. Denature proteins, by replacing functional groups with alkyl groups. |
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Gaseous sterlizers --> A. Ethylene Oxide
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Microbes and endospores,
Requires exposure of 4 to 18 hours. Toxic and explosive in pure form. Highly penetrating. Most hospitals have ethylene oxide chambers to sterilize mattresses and large equipment. |
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8.Peroxygens (Oxidizing Agents)
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Oxidize cellular components of treated microbes.
Disrupt membranes and proteins. |
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preoxygens --> A. Ozone
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Used along with chlorine to disinfect water.
Helps neutralize unpleasant tastes and odors. More effective killing agent than chlorine, but less stable and more expensive. Highly reactive form of oxygen. Made by exposing oxygen to electricity or UV light. |
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preoxygens --> B. Hydrogen Peroxide
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Used as an antiseptic.
Not for open wounds because quickly broken down by catalase present in human cells. Effective in disinfection of inanimate objects. Sporicidal at higher temperatures. |
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preoxygens --> C. Benzoyl Peroxide:
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Used in acne medications.
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preoxygens --> D. Peracetic Acid
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One of the most effective liquid sporicides available.
Sterilant : ( adjv. ) - Kills bacteria and fungi in less than 5 minutes. -Kills endospores and viruses within 30 minutes Used widely in disinfection of medical instruments because it does not leave toxic residues. |
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Effectiveness of antimicrobial
treatment has the following factors : |
1. Number of Microbes: The more microbes present,
the more time it takes to eliminate population. 2. Type of Microbes: Endospores are very difficult to destroy. Vegetative pathogens vary widely in susceptibility to different methods of microbial control. 3. Environmental influences: Presence of organic material (blood, feces, saliva) tends to inhibit antimicrobials, pH etc. 4. Time of Exposure: Chemical antimicrobials and radiation treatments are more effective at longer times. In heat treatments, longer exposure compensates for lower temperatures. |
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What's the rationale for anti-plaque agents ?
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• Mechanical removal of plaque:
- Time consuming - Affected by: gingival architecture, Tooth position, Dexterity, Motivation Incomplete removal of plaque by mechanical means will cause progression and induction of periodontal diseases and caries.. |
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The Antimicrobial Approachs
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1. Mouth Rinses
2. Dentifrices 3. Subgingival Irrigation 4. Controlled Release 5. Systemic Antibiotics 6. Host Modulation Drugs 7. Photodisinfection |
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What ways can we use anti-plaque agents ?
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1) to interfere witht he adhesion of oral bateria to surface and prevent biofilm formation
2) to interfere with co-aggreation mechansims or to affect bacterial vitailtiy which therby prevent further growth of colonies 3) to remove or disrupt existing biofilms |
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What are the ideal proprites for anti-plaque agents ?
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Specificity for pathogenic bacteria
Prevent development of drug resistance. Efficacy: - Decrease plaque formation and gingivitis. - Inhibit overgrowth of other organisms - Inhibit mineralization of plaque to calculus. • Safety : - Non toxic, non allergic and non irritating for oral tissues and teeth. - Limited systemic absorption Acceptable taste, flavor and color. Low cost, available and easy to use. High substantivity |
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Classify the anti-plaque agents
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1)Cationic surfactant (+ve charged) :
A)Bisbiguanids -Chlorhexidine gluconate B) Quaternary ammonium compound : -Benzalkonium chloride 2)Anionic surfactant (-ve charged) : -Na lauryl sulphate. 3) Enzymes : -Mucinase -Mutanase 4) Phenolic compound : -Triclosan. -*Listerine. 5) Herbal extracts : -Sanguinarine. 6) Others : Povidone iodine |
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Chlorhexidine
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It is a cationic surfactant
• Chlorophenyl bisbiguanids • It has both disinfectant and antiseptic properties. • It has also bactericidal and bacteriostatic in nature. |
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describe the Chlorhexidine Mechanism of action ( part 1)
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It binds with teichoic acid in gram positive bacteria
and lipopolysaccharide in gram negative bacteria. – Broad spectrum bactericidal agent – High substantivity • Binds to oral tissues • Released in active form for up to 5 hours – Ruptures bacterial cell membrane releases cytoplasm contents – Reduces adherence capacity of P.gingivalis |
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Antiplaque action of chlorhexidine (part 2)
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1. Prevents pellicle formation by blocking acidic
groups on salivary glycoproteins thereby reducing glycoprotein adsorption on to the tooth surface 2. Prevents adsorption of bacterial cell wall on to the tooth surface 3. Prevents binding of mature plaques |
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what are the side effects of cholorhexidine ?
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– Extrinsic brown staining
– Increase in supragingival calculus accumulation – Alteration in taste perception (temporary) – Bitter taste – Mucosal desquamation |
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List the indications for using systemtic antibitoits
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Not for Gingivitis and Chronic Periodontitis
• Selectively for Aggressive Periodontitis • Selectively for some cases of chronic Periodontitis • Side-effects (Antibiotic resistance) |
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List the common antibitoic therpies for aggresive peridontits
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Tetracyclin (250mg /4days/12-14days)
Metronzidole (500mg/3 times / day / 7 days ) Doxycyeline (200mg /1 time / followed by 400 mg / per day for 14 days ) meterodizoale and amoxicillin (250mg + 375 mg of amoxiallicn 3/daily for 7 days ) meteriodizole and cripofloxin (500mg of each drug twice a day for 8 days ) |
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Single application of in-office subgingival
irrigation with an antimicrobial agent has been shown to have only limited or no beneficial effects over periodontal instrumentation alone, true or false ? |
TRUE
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Irrigation with Water
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Irrigation with water provides an
equally beneficial effect as irrigation with an antimicrobial Agent !!!! |
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Subgingival Irrigation
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• Subgingival irrigation performed
before periodontal instrumentation: -- reduce the incidence of bacteremia -- reduce the number of microorganisms in aerosols |
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Controlled Release Agents
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Rationale:
“substantivity” for sustained & therapeutic dose Consider in specific sites & situations Available Products: -Tetracycline fibers / Minocycline microspheres /| -Doxycycline Hyclate gel / Chlorhexidine chip |
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PerioChip
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• Description:
– Contains 2.5 mg Chlorhexidine gluconate – Biodegradable matrix of hydrolyzed gelatin |
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Photodisinfection
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• Photosensitive compound
(methylene blue • Selectively binds to periodontal pathogens • Using diode laser (670nm Excitation Redox reaction (oxygen species) |
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Host Modulation Drugs
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1)NSAIDS :
• Prostaglandins are important in the pathogenesis of periodontal disease • NSAIDS inhibit prostaglandin synthesis • NSAIDS may slow periodontal bone loss NSAIDS may reduce gingivitis 2) Tetracycline : • Tetracycline can inhibit the activity of host derived collagenases, gelatinase & elastase • Some studies have shown clinical improvement attributed to the anticollagenase effect rather than the antibacterial effect |
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How to write a
prescription? |
• Write clearly
• Preferably use scientific name • Write the form of medication • Write the quantity of the medication • Write the method of application • Write the duration of intake • Write the doze • Write the precautions • Use accurate abbreviations |
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Form of medication
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• Oral Route: Capsules, syrup, tablets…
• Intra-oral topical use: Rinses, lozenges, ointment, gel • External use: ointment, gel, cream… • Injections: intra-muscular (IM), intravenous (IV), subcutaneous (SC) |
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Quantity prescribed
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Specially in restricted medications !!
• For pain medications (30 tab, 20 caps)… • Know the proper dosage to know the proper quantities. Example: Amoxicillin is prescribed for intra-oral infections for one week, three times daily • 7 X 3 = 21 capsules • Children syrup: know the concentration per ml. and the child weight • Medications and doses that require less compliance, especially for long-term use |
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Abbreviations commonly used
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• b.i.d.: used twice daily (every 12 hours)
• t.i.d.: three times daily (every 8 hours) • q.i.d.: four times daily • h.s.: at bed time • Stat.: immediately • d.: once daily • p.c.: after meal • p.r.n.: when needed • Caps.=capsules • tab= tablets |
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Examples: amoxicillin
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Prescribed for adults as 250 mg and 500
mg capsules Amoxicillin 500 mg caps (22 caps) 2 stat then 1 x 3 x 7 p.c. OR; 2 stat then 1 t.i.d. p.c. 7 days |
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Examples of commonly used
medications in dentistry: Pain |
• Ibuprofen
– Syrup (for children) – Tablets (200, 400, 600, 800 mg), or gelcap (Doloraz 400) – Maximum dose per day for healthy adult: 2400 mg per 24 hours – Prescribed t.i.d. – Post surgery: depending on severity 400- 800 t.i.d. p.c. • Paracetamol (acetomenophin) – Children: syrup, supps – Adults: tablets 250, 500, 1000 mg, effervescent tablets – Could come with caffiene or combination of aspirin and caffiene (Tylenol preps, USA) – New fast release: Panadol Actifast (500 mg) – Maximum dose per day for healthy adult: 4 grams per 24 hours – Helpful for patients with gastric irritation, asthma, contraindications for NSAIDs. |
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examples
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Examples:
– Ibuprofen 400 mg tabs 30 – 1-2 tab t.i.d. p.r.n. p.c. – Or; 1-2 tab x 3 p.r.n. p.c. – Paracetamol 500 mg tabs 40 – 1-2 tab q.i.d. p.r.n. p.c. – Or, 1-2 x 4 x 3 then p.r.n. |
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Chlorhexidine gluconate mouthwash
(mouth rinse) |
European preps (BP, 0.2%), US preps (USP, 0.12%)
• Prescribed post-surgical, for patients with challanging oral cavity conditions, severe inflammation, physicallyimpaired patients, nifedipine-induced gingival enlargement and patients with poor mechanical ability to remove calculus) • The duration and frequency of use not agreed upon (days depend on indication) • Common prescription in our clinic is b.i.d. rinse |
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Chlorhexidine gluconate mouthwash
(mouth rinse) example |
• Chlorhexidine 0.2% mouthwash I bottle
• Rinse 2 minutes, 30 minutes after brushing • 10 ml x 2x 14 |
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Antibitoics
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• Many, many…
• Periodontics: aggressive peridontitis – For adults: amoxicillin 500 mg caps (2 stat) and Metronidazole 250 mg tabs (t.i.d. p.c. 7 days) – Or Doxycycline 100 mg (2 stat then 1X1X20) |