Lec 4 Endo (PART 2)

Therapeutics in Endodontics (PART 2)

Antibiotics

Def. of Infection : Colonization of a host by a parasitic species, using the host's resources for
replication and often produce a disease.
Types of Anti-biotic :
1-Antibiotic that Suppress microorganism (Bacterio-static Antibiotic) ‫مهم‬
2-Antibiotic that kills microorganism (Bactericidal Antibiotic) ‫مهم‬
3- Antibiotic prophylaxis ‫مهم‬

Antibiotic Prophylaxis
Def. of antibiotic Prophylaxis : it is Anti-biotic given for (Short-term, with high-concentration, &
broad-spectrum) for specific patients
Cases Require antibiotic Prophylaxis :
1- All patients during the first two years following joint replacement.
2- Immunocompromised / Immunosuppressed patients.
3- Malnourishment.
4- Hemophilia (as this pt. has High liability for infection ) .
5- HIV infection.
6- Type I diabetes (Insulin- dependent).
7-Cardiac conditions associated with the highest risk of adverse outcome:
A- Prosthetic cardiac valve
B- Previous infective endocarditis.
C- Cardiac transplantation recipients who develop cardiac valvulopathy.
D- Congenital heart diseases (CHD).

Dental procedures for Which Antibiotic Prophylaxis for High-Risk Cardiac Patients
(Is and Is Not Recommended)
DENTAL PROCEDURES FOR WHICH ANTIBIOTIC DENTAL PROCEDURES FOR WHICH ANTIBIOTIC
PROPHYLAXIS IS RECOMMENDED PROPHYLAXIS IS NOT RECOMMENDED
1-Restorative care wherein gingival tissues will 1-Injection of L.A through non-infected tissue
be manipulated 2-Dental radiography
2-Surgical & nonsurgical periodontal procedures 3-Placement of removable prosthetics
3-Surgical & nonsurgical endodontic procedures 4-Placement or adjustment of orthodontic
3-Oral surgery (including extractions) appliances or brackets
4-All dental procedures involving manipulation 5-Exfoliation of primary teeth
of gingival tissue , the periapical region of teeth 6-Bleeding (resulting from trauma sustained by
OR perforation of the oral mucosa the oral mucosa or lips)
 Antibiotic Prophylactic Regimens
(‫)الزم نحفظ الجدول دا بالدوزج عن ظهر قلب‬
Pt. Group Antibiotic Dose is single , (30-60mins before procedure)
Adults Children
Able to take oral Amoxicillin 2g 50 mg/kg
medication
Unable to take oral A-Ampicillin A- 2g IM or IV A- 50 mg/kg IM or IV
medication B-OR Cefazolin or B- 1 g IM or IV B- 50 mg/kg IM or IV
ceftriaxone
Allergic to penicillins or A-Cephalexin A-2g A- 50 mg/kg
ampicillin and (able) to B- OR Clindamycin B-600 mg B- 20 mg/kg
take oral medication C-OR Azithromycin or C-500 mg C- 15 mg/kg
clarithromycin
Allergic to penicillins or A-Cefazolin or A-1 g IM or IV A- 50 mg/kg IM or IV
ampicillin and (unable) ceftriaxone B- 20 mg/kg IM or IV
to take oral B-OR Clindamycin B-600 mg (IM or IV)
medication

Mechanism of bacterial resistance to anti-biotic

1-Drug tolerance (‫)يا اما البكتريا تتحمل المضاد الحيوي‬ ‫(يا اما البكتريا تكسر المضاد الحيوي‬
2-Drug destruction (B-lactam inhibitors using B-lactamase Enzyme ) )‫لكتميز انزايم‬-‫بالبيتا‬

FORMS OF BACTERIAL RESISTANCE TO ANTIBIOTICS ARE

1-Presence of outer phospholipid covering prevents access of antibiotics to their site of action within
the microorganism.
2-Deposition of a protein protective layer to the cell wall (‫ )كنوع من أنواع الحماية‬.
3-Alteration in the enzymatic target sites for antibiotics

RESISTANCE TO ANTIBIOTICS IS ACHIEVED BY ONE OF 3 APPROACHES.

1- Natural (mutational): spontaneous, random mutation of bacterial genes independently of contact
to antibiotics.
2- Acquired: occurs in presence of contact with antibiotics.
3- Transferred (infectious): conferring resistance from an antibiotic-resistance bacterium to an
antibiotic-sensitive bacterium (‫ بتدي للي معندهاش‬، ‫)البكتيريا الي عندها الجين الي عامل ريزيستانت لنوع مضاد حيوي‬
MECHANISM OF ACTION OF ANTIMICROBIAL AGENTS
Action Agents
1- Inhibition of cell wall synthesis. Penicillins, Cephalosporins, vancomycin.
2- Inhibition of protein synthesis. Tetracyclines, chloramphenicol , lincomycin
Ciprofloxacin, metronidazole (Flagyl)
3- Interference in genetics ‫مهم‬. NOTE ‫مهم‬: (Ciprofloxacin, metronidazole (flagyl) are used in
Intracanal medication as in Triple & Double antibiotic paste )
4- Anti-metabolic action. Sulfonamides.
 Antibiotic Drug clearance
1-Renal : (Penicillin ,cephalosporin)
2-Non-renal : (Erythromycin ,Chloramphenicol)
NOTE (‫)تجميعة‬: Penicillin and cephalosporin → both of them has effect on (Cell wall) & both of them
have common (chemical structure) & Both of them are (excreted from Renal)

GENERAL TOXIC EFFECTS OF AB.

Drug Direct toxicity Allergy
penicillin free Allergy highly antigenic (allergenic)
Erythromycin Transient deafness (‫طرش مؤقت‬/‫ )صمم‬low
Tetracycline Tooth discoloration Moderate

PENICILLINS ARE CROSS ALLERGENIC

NOTE: Antigenic test is done while giving penicillin by injecting 0.1cc. SC.
-if Rash & Redness occurs on the Skin → there is +ve allergy to penicillin (so, Avoid using penicillin in
this case )

Adverse reaction
NOTE: Penicillin is the most commonly allergenic of all drugs.
Allergenic reaction to penicillin can be classified into:
1-immediate (20 mins) → ch.ch by Urticaria , anaphylactic shock
2-accelerated (48hrs) → ch.ch by Urticaria , fever, laryngeal edema
3-Late (3days) → ch.ch by Urticaria , serum thickness ,arthralgia , anemia , purpura, erythema
multiform

NOTE: A Clear medical history from pt. should be taken (By asking them if they have ever taken
Penicillin/amoxicillin OR NOT ? ) ‫ ال انا الزم اساله اذا كان اخد قبل كدا وال ال‬، ‫مينفعش اديه للعيان كدا وخالص‬
 ANTIBIOTIC AGENTS
(PENICILLINS)
A general term for a closely related antibiotics that differ in (‫ وبيختلفوا فالحاجات دي‬، ‫ )يعني البنسلين أنواع كتير‬:
1- Antibacterial spectrum.
2- Resistance to gastric acid.
3- Destroyed by beta-lactamase (penicillinase).
Classification of penicillin:
A-Natural penicillin (penicillin G).
B-semi-synthetic (penicillin V)
A-Natural penicillin (penicillin G) B-semi-synthetic (penicillin V)

NOTE: completely natural penicillin NOTE: semi-synthetic penicillin (Similar to

NOTE: when orally administered 2/3rds or 3/4th penicillin G)
are destroyed in the stomach (‫ )بيتكسر فالمعدة‬.
NOTE: we Don’t use penicillin G Nowadays as it NOTE: Stable and resistant to gastric acid.
is destroyed in stomach
NOTE: Approximately 65% of the drug absorbed
Spectrum: Generally effective against: when taken orally.
1-Gram +ve
2-Gram -ve cocci. NOTE: we use penicillin V as it is Can resist
3-Most anaerobic organisms Gastric acid in stomach

Organism resistant:
1-Most Gm-ve bacilli
2-Enterococci
3-Staphylococci of community and hospital
variety

Actively secreted by → kidneys

Broad-spectrum penicillin
(Ampicillin – Amoxycillin)
Amoxycillin & Ampicillin are Effective against :
1-Gm+ve aerobes & anaerobes.
2-Gm-ve aerobes & anaerobes.
NOTE: Amoxycillin & Ampicillin → have (Beta-Lactam) , thus they can be destroyed by (B-Lactamase
Enzyme) that the bacteria produce it as a Defense mechanism → ‫وبالتالي وال هيبقى ليه الزمة وبتاخده عالفاضي‬
Clavulanic acid has been added to Amoxycillin & Ampicillin as it is Effective against : B-lactamase Enzym

NOTE: Some of them are mixed with anti-penicillinase enzyme OR Anti-Cephalosporinase such as:
1-Augmentin (Amoxycillin + Clavulanic acid)
‫) و‬Clavulanic acid( ‫ هيبقى فيهم‬Unasyn ‫ و الـ‬Augmentin ‫كدا الـ‬
2-Unasyn (Ampicillin + Sulbactam) B-Lactamase Enzyme ‫) واالتنين دول هيكسرولي الـ‬sulbactam(
 Cephalosporin Erythromycin clindamycin Tetracycline Metronidazole
Properti Broad spectrum Macrolide ABs With 1-Clindam (Terramycin) Amerazal
es Classified into 4 large macrolide ring 2-Dalacin-C (Declomycin) Flagyl
generations (Zithromax) (Vibramycin)
Adminis 1-Oral (Keflex) 1-Orally Orally Orally Orally - IV-
tration (Duricef) 2-Destroyed by Incomplete rectal
2-Parenteral gastric acid so absorbed by Completely
(Velosef) (enteric coated) GIT absorbed by
GIT

1-Skin rash 1- Allergy 1- 1-most 1-Metalic test

(cause allergy 2-transient deafness pseudomembr directly toxic
with penicillin) (if it is given for long anous colitis AB 2-Xerostomia
as they Both have period ) (fatal)
Adverse same chemical 3-nausea, diarrhea ‫هنشرحها بالتفصيل‬ 2-Liver 3-mutagenic
Structure
effects 4-vomiting damage Teratogenic
2-nausea, carcinogenic
2-Skin rash – diarrhea 3-Staining of so, avoid for
Fever
teeth jaundice long term
3-vomiting nausea,
3-Serum
diarrhea 4-Pt. with PA
sickness -
4-vomiting infection feels
metallic taste
4-Eoxinophilia
if used as ICM
Detoxifi Kidney Liver Liver Kidney liver
ed
1-Streptococcus 1-Aerobic and some Similar to (ER) 1-Bacteriostatic Bactericidal
staphylococcus anaerobic BUT Greater to gm+ve and against
(Most 2-Streptococci and activity gm-Ve. obligate
anaerobic) some forms against anaerobic
staphylococci. anaerobes 2-
spectru 2- Gm +ve are 3-Not effective Staphylococcus NOTE: avoid
& streptococcus
m more than Gm- against Gm -ve prescribing
ve. aerobic bacilli. metronidazole
3-Neisseria, alone in general
4-Bactericidal
Actinomyces (as it will cause
3- Sensitive to Bacteriostatic
and Shigella. super
beta-lactamase Depend on Conc. Of
imposition of
enzymes drug
aerobic )
(chephalocpoin
ase) NOTE:
metronidazole
can be used
alone as ICM

1-Adult dose Adult dose 250- Adult dose Adult dose Adult dose
250-500mg/ 6 500mg/ 6 to 8 hours. 150-300mg/ 6 1-2 gm 250-500mg/ 6
dose to 8 hours. to 8 hours. to 8 hours.

2-Children
125mg syrup
 pseudomembranous colitis OF clindamycin
it is (fatal)
NOTE: pseudomembrane consist of - ‫دا غشاء جوا القولون بيتكون من الحاجات دي‬- → (fibrin, mucous,
inflammatory cells, epithelial debris)... causing necrotizing inflammation of the bowl.
NOTE: This membrane covering the mucosa → and if it peels off → bleeding occur→ ending with death

NOTE: clindamycin is used

with Metronidazole instead
of Erythromycin in case of
using intra-Canal medication
(ICM)
Bc: clindamycin has Greater
activity against anaerobes
than Erythromycin

Helpful Tips
1-ABs. are not curative, except in patients with compromised immune system.
2-ABs. are not substitutes for intervention.
3-The most important decision is not which ABs. To be used BUT whether to use one or not
4-Multiple ABs. Used → meaning increase of drug resistance micro-organism (super infection).
5-The majority of infections of endodontic are treated without the need for ABs.

Conditions (Not Requiring) Antibiotics

1- Pain without signs and symptoms of infection.
2- Symptomatic irreversible pulpitis
3- Acute periradicular periodontitis
NOTE: Penicillin Doesn't reduce; (A- Spontaneous pain , B- Pain on percussion , C- NO. of analgesics)
4- Teeth with necrotic pulps → (Bc: the Abs. will not reach the necrosed pulp due to absence of blood
circulation )
5- Teeth with a sinus tract (chronic periradicular abscess) → (doesn’t need Abs. Bc: there is
Evacuation for the pus )
6-Localized fluctuant swellings.

NOTE: Cleaning/shaping + irrigation (without Antibiotic therapy) = healing of endodontic infection

NOTE: healing of endodontic infection Requires → (removal of the cause)
NOTE: Intracanal medication (ICM) → used in (persistent pain , foul odor) DON’T GIVE ORAL ABs
 Principals of ABs. dosing
(‫)دي نقط مهمة‬
A-Lower Dose of Antibiotic therapy is better that Higher Dose of Abs Therapy Due to ;
1-Shorter the duration of Antibiotic (so, Decreasing Side effect & Decreasing allergy )
2-lower risk of toxicity.
3-lower risk of developing resistant micro-organisms.
NOTE: using a (Narrow spectrum AB) is better than using (Wide spectrum AB)

DEF. of Half life : the time takes for amount of drug's active substance in your body to reduce by 1/2
another DEF. of Half life : (it is the time that the drug concentration is Reduced by 1/2 in blood )
DEF. of steady state : blood level of any drug (is = 3-5 times drugs 1/2 life)
NOTE: when level of (Absorption) & (excretion) become Equal & there is balance between them →
this is considered as steady state
NOTE (BOOK- ‫)لتوضيح الفكرة العامة للموضوع‬: The shorter the serum half-life of the drug → the shorter the
dosing interval will need to be in order to maintain continuous therapeutic blood levels of the drug.

B-it is advisable to Begin with loading dose of antibiotic therapy (initial dose higher than
maintenance dose) if;
1- Half life of the drug is more than 3h.
2- Delay of 12hr or longer to achieve a therapeutic blood level is expected.
NOTE (BOOK- ‫)لتوضيح الفكرة العامة للموضوع‬: Most antibiotics used in the TTT of orofacial infections have
a half-life shorter than 3 hrs BUT, due to their acute nature, → most orofacial infections require
therapeutic drug blood levels sooner than 12 h.
NOTE: the initial loading dose → is given to make the drug's Effect start rapidly & to make the blood
highly concentrated with the Drug & to achieve a therapeutic blood level …… then the maintenance
dose is given

Example :
Amoxicillin half life is → 1-1.5 hr
So, steady state blood level is → 3-7.5 hrs (3-5 times drugs 1/2 life = 3x1 OR 3x1.5)
So , There is delay in achieving therapeutic AB. Blood levels, thus loading dose is recommended
in case of (acute orofacial infections)

NOTE (EXTRA IN BOOK ): A common misconception claims that prolonged antibiotic therapy is necessary
(after clinical remission of the disease) to prevent "rebound" infections from occurring.
NOTE (EXTRA IN BOOK ): Orofacial infections don't "rebound" if the source of the infection is eliminated.
NOTE (EXTRA IN BOOK ):Most orofacial infections persist for 2-7 days and often less.
NOTE (EXTRA IN BOOK ):Patients placed on antibiotic therapy for an orofacial infection should be
clinically evaluated on a daily basis .
When there is sufficient clinical evidence that the patient's host defences have regained control of the
infection and that the infection is resolving or resolved → the antibiotic therapy should be terminated.
 New Antibiotic Guidelines
(By Ashraf F. Fouad)

1-patients with AAA and systemic involvement, OR systemic disease compromising the immune
response, antibiotic prescription is probably indicated for the patient with LAAA who will not receive
immediate TTT BUT will be referred to other practitioners or a future appointment for management

2- Beta-lactam- based antibiotics (primarily amoxicillin 500 mg 3 times per day for 3 to 7 days)
remain the first line of effective antibiotics for patients in whom antibiotics are indicated
These regimens can be complimented with metronidazole 500 mg three times per day in resistant
infections
‫ وساعات‬، ‫ يعني الخيار األول ليا للمضاد الحيوي للناس الي محتاجاه هو االموكسسلين‬: )‫نوت (بالعربي‬
) anti-resistant infection ‫بحط معاه ميترونيدازول (في حالة‬

3- For the patient who is allergic to penicillin, the patient needs to be asked about the type of
reaction that they received.
NOTE: True allergy is identified only for patients with history of anaphylaxis, angioedema or hives.
NOTE: If the patient did not have these reactions , oral cephalexin (500 mg. 4 times per day, 3 to 7
days) would be indicated
‫اورالي) وطبعا الزم نراجع الجدول الي‬- ‫ بديه (سيفالكسين‬، ‫ يعني لو العيان عنده مشكلة وحساسية من البنسلين‬: )‫نوت (بالعربي‬
‫قولنا نحفظه عن ظهر قلب فوق‬

4- For patient with true allergy to penicillin, the primary alternative antibiotic recommendation has
changed.
It is now (azithromycin) with a loading dose of 500 mg, and then 250 mg for 4 additional days.
NOTE: Clindamycin now has a U.S. Food and Drug Administration black box warning for Clostridiaides
difficult infection
) azithromycin( ‫ بديه‬، ‫ يعني لو العيان عنده مشكلة وحساسية شدييييدة من البنسلين‬: )‫نوت (بالعربي‬
pseudomembranous colitis ‫) عشان دا يعمل‬Clindamycin( ‫وبالش اديه‬

5-For all patients on antibiotics, the antibiotic treatment is discontinued as soon as definitive
treatment and improvement of the condition occurs (as short as 3 days), rather than to the full
course of the prescription
‫" اختفت‬Signs & Symptoms ‫ ساعة من لما العيان يقولي "الـ‬84 ‫ بوقفه بعد‬.. ‫ بوقف المضاد امتى ؟‬: )‫نوت (بالعربي‬
) ‫ أيام استخدام (كل الي عملته زودت يومين استخدام مش اكتر‬5 ‫كدا هيوقف المضاد بعد‬، ‫ أيام‬3 ‫يعني مثال لو قالي االعراض اختفت بعد‬
) ‫ أيام استخدام (كل الي عملته زودت يومين استخدام مش اكتر‬7 ‫ كدا هيوقف المضاد بعد‬، ‫ أيام‬5 ‫يعني مثال لو قالي االعراض اختفت بعد‬