endo sheet # 2

بسم الله الرحمن الرحيم
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By the name of ALLAH

Second Endodontology lecture

Pulp space anatomy and access cavities.
• Its very imprtant for us to know about root canal morphology because clear understanding of it is an essential preoperative to succeful root canal treatment .
• Note:the difference between endotontics and endodontology:
 Endodontology:is the science that study the form,function and treatment of pulp
 Endodontics:the procedure concern of treatment of pulp.
• Its very important to try to develop a 3 dimensional visual picture of the expected location and number of canals in a particular tooth.

Roles of Radiograph
• it helps a lot in root canal treatment
• its considered as the eye of the dentist, because it shows the dentist the roots hidden inside the bone which cant be observed clinically.
• Canals, shapes,numbers of the roots, previous root canal fillings, inflammation and the length of canals ,all can be seen in
• Although radiograph has a lot of advantages ,it also has limitations, because it shows 2 dimensional image for a 3 dimensional object. So preoperative radiograph must be taken from many angles in order to have more information about root canal morphology.
• Before starting any root canal treatment we must have preoperative radiograph.




Complexity of pulp space
Pulp space is very complex, and the pulp canal system (canals) may branch,divide and rejoin, so its not just a simple canal, but intercanal communication,division and lateral canals.
In a radiograph, mesial and distal canals appear, but in staining and clearing technique ,lateral and intercanal are obvious in the pulp space.


Methods of studying root canal morphology
1)gram section:cross section in the tooth that allow us to know the number and shape of the canals in a certain root,
2)staining and clearing technique: open the pulp chamber, then inject ink in it under pressureto allow the ink to fill all the spaces. Then cleaning by decalcification by certain types of acid.
3)radiography: we talked about it.

Pulp-dentine complex
Pulp system is divided into : the coronal part which is called the pulp chamber and the radicular part.
Dentine sorrounds the pulp chamber and is composed of dentinal tubules that contain dentinal fluid.
Odontoblasts are in the pulp chamber and the odontoblastic processes extrude to the dentinal tubules. So the pulp dentine are very closely related because of the presence of dentinal tubules. And this is very important clinically because any microorganism affect dentine can reach pulpand inflammatory reaction occur, then either reversible pulpitis or irreversible pulpitis occur due to pulp necrosis (if the insult was severe).
So, periradical inflammation (apical periodontitis) and it may extend to the bone and causes Osteomilitis .
Also if any infection occur in the pulp, the microorganism can penetrate the dentine through dentinal tubules.
So dentinal tubules are considered as a reservoir of microorganism in pulpal infection cases .
This makes the endodontic treatment more difficult , so the procedure must be administered not only to treat the pulp but also dentinal tubules.
Note 1 : the treatment doesn’t depend on the origin of the microorganism (if its from the pulp or dentine).
 Note 2 :dentine form the bulk of mineralized tissue of the tooth
 Dentinal tubules make up 20-30% of total volume of dentine.
 Surface area (diameter) of dentinal tubules increase 3 times in pulp than amelodentinal junction ,,, so,, any problem will be harder to deal with if it was deeper (more toward the pulp) rather than being superficially , because the tubules increase toward the pulp.


Clinical significant
 Toward the pulp, the permeability increases, so any microbial, chemical or mechanical insult will have more effect.
 Dentinal tubules form a reservoir of microorganism in pulpal necrosis cases.



Component of the root canal system
Pulp chamber,,,,,, and radicular part.
 The highest point in the pulp chamber is called pulp horn,, getting elderly,recession and formation of more dentine occur.
 The point where pulpar floor meets root canal is called root canal orifice.
 The point where root canal exit to the periodontium is called apical foramen.
 Canals that connect the main canal to the periodontium is called accessory canals.
NOW,, the accessory canals:
When being in the coronal and middle two thirds of the root then they are called lateral or horizontal canals.
In the apical part they are called accessory or apical delta.
If they were in the between lateral and furcational area they are called furcational canal.






Dental histology!!!!!
 These canals appear during development from Hertwigs epithelial root sheath.
 Odontoblasts (from the pulp) form the dentine.
 First hard structure to be formed in the tooth is dentine, and once its formed it induces ameloblasts to form enamel.


Vertucci canal configuration
Classified the root canal morphology inside single root into 8 types:
Type 1: canal starts from one orifice and ends in one apical foramin.
Type 2: start from 2 orifices on the junction between root and crown then join each other to end in one apical foramin.
Type 3: one big orifice then divide into 2 canals then rejoin and ends in one apical foramin.
Soooo ,,, types 1,2 and 3 end in one apical foramin.
Type 4: two orifices start and continue separated from each other and end in 2 apical foramina.
Type 5: one orifice, then, near the apical part of the root it divides into 2 canals and end into 2 apical foramina .
Type 6: start from 2 orifice then rejoin in the middle then re divide and end in 2 apical foramina.
Type 7: start as one then divide into 2 then rejoin then re-divide into 2 and end as 2 apical foramina.
Soooo,,, types 4,5,6 and 7 end in 2 apical foramina.
Type 8: 3 canals separated from each other (start from 3 orifices and end in 3 apical foramina).
Note: the easiest type to deal with is type 1 .

Summary of Vertucci classification:
Type 1 >>>>> (1)
Type 2 >>>>> (2-1)
Type 3 >>>>> (1-2-1)
Type 4 >>>>> (2)
Type 5 >>>>> (1-2)
Type 6 >>>>> (2-1-2)
Type 7 >>>>> (1-2-1-2)
Type 8 >>>>> (3)


Weine classification
Another classification contains 4 types
Type 1 >>>> (1)
Type 2 >>>> (2-1)
Type 3 >>>> (2)
Type 4 >>>> (1-2)



Internal anatomy
• The shape of the pulp system reflects the surface outline of the crown and the root.
• Pulp space is broader Bucco-Lingually than Mesio-Distally (important because in radiograph it shows only the mesio-distally dimension),,, and this is another limitation in radiograph.
• The diameter of the apical canal decreases toward the apical foramin, and reaches its narrowest point at apical constriction.



Apical anatomy
• Studies indicate that the apical foramen rarely coincide a position with anatomical apex.
NOW,,,, the difference between apical foramin and anatomical apex (radiographic apex),,,
Anatomical apex>>> the last point on the root appears in radiograph.
Apical foramin>>> the point where canal exit to the periodontium.
• The average distance between radiograph foramen and apical foramen is 0.2-2.0 mm
• The average distance between apical foramen and apical constriction is 0.5-1.0 mm.
So,,, 3 important points>>>
Radiographic apex,,, apical foramen (major apical diameter),,, apical constriction (minor apical diameter).
NOTE: the ideal way to treat is to end the instrumentation at the apical constriction, because it forms a natural barrier between root canal system and periodontium.

Cement-Dentinal junction.
• Where cementum meets dentine.
• This point is the end of pulpal tissues and the beginning of periodontial tissues.
• Location varies between anterior,posterior, old and young teeth, because cementum deposition is a dynamic process .

Apical foramina
The shape of the space between the major and the minor is described as funnel shape, hyperbolic or morning glory.

Accessory and lateral canals
• Linking pulp and periodontium
• Clinical significant >>> reservoir of microorganism ,so if mechanical instrument is not enough for complete treatment and cleaning, we use chemical methods.
• Accessory canals may be demonstrated :
 Histology
 Clearing and staining techniques
 Clinical radiograph after root canal filling treatment.
Correction are more than welcomed 

2nd endo lec. On sun. 26\9
Done by : Muna Jamal Sawwan
Sunday 26\9\2010