For dental school students

1. By : Dr. Haval Jalal

2. Apical periodontitis
Inflammatory conditions of the periodontal tissue that are caused
by irritation in the pulp canal system.
Can occur laterally or in apical region.

3. • Hallow tube theory suggest that necrotic pulp canals as space into which
tissue fluids from Periapical area would flow & mix with dead tissue to
form an irritant cocktail.
• Miller 1890 discover microorganism in necrotic pulps.
• Kakehashi et al in 1965
germ free animals exposure of pulp tissue to oral environment can remain
healthy for months and even classified bridge can be formed, while in
animals whose mouths containing microorganism’s pulp will die after
exposure to the mouth.
• tissue & tissue fluids in the pulp canal space are not the irritant factor them
self’s, however it act as a house of microorganisms.

4. 1 - oral flora pulp space
carious lesion, trauma, or operative dentistry.
2 - oral flora =500 species necrotic pulp tissue = 2-8 species
predominantly aerobic gram +ve, but with the time they give way to anaerobic gram –ve
3 - single species Periapical inflammation
mixed infection larger lesions.
4 - symptoms Gram –ve, anaerobic Prevotella, Porphyromonas, Fusobacteriium
proteolytic enzymes ,
compromise host defend mechanism

5. Dental caries pointed as most common cause , crown preparation might associate with
loss of vitality .
Prevalence of apical & marginal periodontitis by Eriksen in 1998
It can be said that apical periodontitis is more prevalent in western
societies than advance forms of periodontal disease

6. Summarization Of Endodontic Qualities In No. Of Countries
We can see that the technical qualities of endodontic
treatment are disappointing in most countries.
Thus it seems that apical periodontitis is better prevented
than allowed to develop difficult costly treatment.

7. Natural Defenses against the Oral Environment
1-Enamel. Isolation.
2- Dentine/pulp complex Restriction of diffusion.
3-Apical Periodontium Inflammation.
Inflammation
1-Enamel
simple physical barrier , 2.5 mm thick over cusp tips , hardness of mild
steel, chemically 96% = mineral , 4% = organic matter
It has good capability remenrlization after exposure to acids, but it’s
incapable of new growth after structure loss
Preservation of enamel is one of most important duty of dentist.

8. 2-Dentine/pulp complex
anatomically & functionally linked to each other
The defensive capability of pulp is greatly compromised if it loses dentine
coverage, at the same time dentine offer little defense against microbial
infection without help of functioning pulp, thus exposed dentine should be
treated as living tissue.
A- Isolation:
2mm thickness = good thermal protection
1mm or less = Decrease the thermal protection
such as in case of crown preparation situations.

9. B- Restriction of diffusion
exposed dentinal surface provide a path through its tubules
for external factors to injure pulp.
When irritant are applied to dentine it respond in 3 ways ;
1- dilution of the irritant by constant outward flow of tissue
fluid,
2- by buffering action of tissue fluid.
3- possibly by humoral immune activity.
tubular fluid is changed, disruption of odontoblast layer
derived plasma protein (albumen, fibrinogen, IgG) from pulp
vasculature, increase viscosity of tubular fluid thus it reduce
dentinal permeability.
Slowly advancing carious stimulate hard tissue deposition
with in dentinal tubules to narrow lumena at the exposed
dentinal surface, while near the pulpal surface of tubule
tertiary dentine lie down to seal off the tubules.

10. C-Inflammation
Consider as final layer of defence.
it’s helpful in killing micro-organisms and dilute irritant agent by
inflammatory exudates.
pulpal pressure
Although pulp is surrounded by rigid case which is an able to swallow
to accommodate pulpal pressure raising due to inflammation, and to
overcome such situation pulp is provided with
1- ground substance rich with Proteoglycan, which are comprisable
and physically
2- Unusual aterio-venous shunt allowing diversion of blood flow
away to reduce pressure.

11. 3- Apical Periodontium(Inflammation)
Failure of defensive mechanisms
Pulp tissue break down
Toxic product
Diffuse to apical area
Inflammation
It can be regarded as an attempt of the body to provide another layer of
defence against the microbial invasion

12. 1- Local Anesthesia
Dental local anesthetic contains vasoconstrictors. Affect pulp blood flow.
Pd.L. infiltration
lidocaine with 1: 100 000 epinephrine pulpal blood flow 75% within 5min
normal after 75min.
lidocaine with 1:800 000 epinephrine blood flow by 30% for about 1hr
Pulp tissue can with stand reduce blood flow
and ischemia for more than hour by switching
to anaerobic metabolism.
But the problem occur when the reduce in blood
flow is combined by heat generation which
might cause tissue injury.

13. 2- Hard Tissue Preparation
A- Area of Preparation
excavation of caries lesion is likely to
open the fresh tubule (which are easy
pathway of irritant to the pulp).
Alternative and more conservative
method have been introduced such as
Lasers, sand –blaster, carisolv ….etc.
B-Depth of Preparation:
depth of cavity preparation
pulp injury
Due to reduced capacity of thinned
dentine to provide thermal protection and
dilution of irritants.
C-Heat generation: dentine preparation
large bur, with heavy pressure, without
water cooling
high speed bur, light intermittent touch,
focused water spry
reduce pulp damage chance due to heat
generation.
D-Dessication:
further injury can come from
over drying
stream of air are able to force fluid out of
dentinal tubules, which can extract
odontoblast from the pulp.

14. 3- Dental Material and the Pulp
evaluating dental material in base of whether micro-organisms are present or not after
cavity preparation, or entering the cavity through microleackage
.
A- Ability to bond or seal interfaces with dental hard tissue
Long term selling of GIC resin bonding system ??
Amalgam Not form chemical bond.
Cavity varnishes, priming, selling amalgam cavity with bonding agents may represent a wise
precaution before restoration non-sealing materials.
Poor adapting crown and bridge uncover wide area of freshly cut dentine.
B- Dimensional stability during setting
Most of the materials contract to some degree during setting, leading to marginal
failure. this can reduced by incremental build up, and curing marginal, use of flow able
material, and by directing curing light in the knowledge that material will cure toward it
C- Coefficient of thermal expansion Restorative material who don’t have coefficient of
thermal expansion comparable with dental tissue will express marginal break down.

15. Preserving Injured Pulps
1-Indirect Pulp Capping
Technique used to avoid exposing the pulp of vital symptom free tooth by excavating
a deep carious lesion .
Thus after using of rubber dam it’s possible to excavate the periphery of the lesion,
and then dressing the lesion with setting CaOH.
2-Stepwise Excavation
Soft dentine in the depth of the cavity is treated with CaOH, then the cavity sealed
temporarily, 2 month later, the cavity is re-entered for complete caries removal.

16. 3-Direct Pulp capping
with a well sealing rubber dam, the pulp wound cleaned, and haemostasis secured
with NaClO, classically pulp wound covered with setting CaOH to encourage
reparative dentine bridge formation.
Anther products introduced like dentine bonding composite, MTA, application of
human growth factors as alternatives to CaOH..
4- Pulp Amputation
In immature tooth where tooth formation not completed yet, and the pulp has great
healing ability, it’s recommended to amputate affected pulp tissue and leave healthy
radicular pulp to complete tooth development.
Working under septic condition, infected coronal 2-3 mm of pulp are removed, with
high speed diamond bur under sterile saline irrigation, then bleeding should controlled
with NaClO washing, same wound dressing agent are applied like CaOH, MTA… etc.

17. Early treatment of infected pulp before proceed to apical periodontitis will guarantee
better prognosis
1-Creating Clean Environment Rubber Dam
2- Entering the system Clear entrance of canals
3-Remove of Tissue Clear access to canal system Barbed broach
4-Determinig the Level of the Wound Radiograph + apex locator
5- Single or multi visit care (Preapical periodontitis presence )
6-Preserving the Clean Environment Gutta percha

18. • Root canal treated teeth have no physical and
responsive action to protect apical periodontium
from oral flora, also it’s at risk of cuspal fracture,
and therefore it’s critical to restore the tooth as
soon as possible.
• As pulp less tooth are incapable to sensation, it’ll
not alert the patient about caries or any other
damage, thus careful periodic examination with
aid of radiographic image to evaluate the coronal
and apical periodontal situation is necessary.