Week 13: Endo Wrap-Up

Question 1

What are the primary objective in shaping and cleaning?

Answer 1

• Remove infected soft and hard tissue
• Give disinfecting irrigants access to the apical canal space
• Create space for the delivery of medicaments and subsequent obturation
• Retain the integrity of radicular structures

Question 2

Describe the implications and microbiology of bacterial persistence after treatment procedures

Answer 2

Implications and microbiology of bacterial persistence after treatment procedures
* Bacteria have to reach a quorum of cells sufficent to cxause disease (bacterial load)
* Before a threshol is reached, no clincal signs and symptoms of the disease are evident
* After bacterial levels reach and excess that threshol, the infectious disease (apical periodontitis) is established
* If treatment procedures do not succeed in reducing bacterial levels below that threshold, the disease will persist
* Successful treatment does not necessairly sterilize the root canal but reduces bacterial populations to subcritical level compatible with healing

Question 3

What are the microbiological goals of endodontic treatment?

Answer 3

Microbiological Goals of Endodontic Treatment
* Eradicate bacterial colonization or reduce the bacterial load to levels that permit periradicular tissue healing

Question 4

Define P= N.V.I/ R

Answer 4

Pathogenicity= Number of Microbial Cells, Virulence, Interactions

R= Resistance, host immune system

Question 5

What are mechanical objectives?

Answer 5

Mechanical Objective
* Canals should be prepared to a uniform and continuous taper
* Another important mechanical objective is to retain as much cervucal and redicular dentin as possible so as not to weaken the root structure, thereby preventing root fractures
* An ideal mechanical objective of root canal instrumentation is that all root canal surfaces are mechanically prepared. However, this goal is unlikely to be met with current techniques.

Question 6

What are the biological objectives?

Answer 6

Biological objective
* One of the primary goals of root canal instrumentation is to eradicate bacterial colonization or to reduce the bacterial load to levels the permit periradicular tissue healing
* For optimal disinfection, preparation shape and antimicrobial related through the efficent removal of infected pulp and dentin and creation of space for the delivery of irrigants

Question 7

Discuss irrigants in RCT

Answer 7

Sodium Hypochlorite
* NaOCl is the most used irrigating solution because of its antibacterial capacity and the ability to dissolve necrotic tissue, vital pulp tissue, and organic components of dentin and biofilms in a fast manner

Toxicity
* If NaOCl is used without caution, it is very toxic and destructive to intraoral soft tissues, periradicular vasculature, and canellous bone where it can elicit severe inflammatory responses and degradation of organic components

Question 8

What is the most used irrigating soultion in endodontics and why?

Answer 8

• Sodium hypochlorite is the most used irrigating solution in endodontics
• It has an expressive antimicrobial action and tissue dissolution capacity

Question 9

Describe irrgiants in root canal treatment

Answer 9

Chlorhexidine
* The antibacterial efficacy of CHX as an irrigant is concentration-dependent. It has been demonstrated that 2% CHX has better antibacteria efficacy than 0.12% CHX in vitro.
* NaOCl has an obvious advantage over CHX with the dissolution capacity of organic matter that CHX lacks.
* The combination of NaOCl and CHX produces a change of colour and a toxic insoluble precipitate, formaton of 4-chloroaniline, that may interfere with the seal of the root obturation

EDTA
* EDTA is used once the cleaning and shaping are completed
* It is often suggested as an irrigation solution because it can chelate and remove mineralized portion of the smear layer
* EDTA is generally used in a concentration of 17% and can remove the smear layers when in direct contact with the root canal wall (3 minutes)

Question 10

Define patency

Answer 10

Patency is defined as where the apical portion of the canal is maintained free of debris by recapitulation with a small file through the apical foramen

Question 11

Describe glide path

Answer 11

Glide Path
* A patency file is a small K-file (usually a size #10 or #15) that is passively exened through the apical foramen. It is believed to remove accumulated debris, help maintain WL, and therby translate into greater clinical success.
* The file reaching the apical foramen has already foormed a so-called glide path. This term has been used in endodontics for more than a decade and relates to securing an open pathway to the canal terminus.
* The presence of an appropriate glide path is indicated by the fact that a straight size #15 K-file can passively and smoothly travel to WL with long in-and-out movements.

Question 12

Describe warm vertical condensation

Answer 12

Warm Vertical Condensation
* Warm thermoplastic techniques are advantageous because they facilitate movement of the plasticized GP within the obturated RCS. This creates a more uniform mass of resultant GP and fill irregularities and accessory canals better than lateral complication.
* Disadvantages include a slight risk of vertical root fracture because of compaction forces, and the potential for overextension of obturation materials into the periradicular tissues

Question 13

Define the following:
* Anatomic apex
* Apical Constriction (minor apical diameter, minor diameter)
* Apex locator
* Apical Patency
* Apical Stop
* Apical foramen
* Foramen (pl.formaina)
* Radiographic length
* Crown-down preparation (step-down preparation)
* Periapex
* Recapitulation

Answer 13

• Anatomic apex- The tip or end of the root as determined morphologically
• Apical Constriction (minor apical diameter, minor diameter)- The apical portion of the root canal having the narrowest diameter; position mat vary but is usually 0.5-1.0 mm short of the center of the apical foramen
• Apex locator- an electronic insturment used to determine the root canal working length or perforation; operates on the principles of resistance, frequency or impedance.
• Apical Patency- a techniques where the apical portion of the canal is maintained free of debris bu recapitulation with a small file through the apical foramen
• Apical Stop- The apical end of a root canal preparation that prevents further advancement or progression of both endodontic insturments and obturation materials
• Apical foramen- The main apical opening of the root canal
• Foramen (pl.formaina)- A natural opening or passage especially into or through a bone; also describes openings in the root structure that communicate with the dental pulp and generally contain neural, vascular, and connective elements
• Radiographic length- The tip or end of the root is determined radiographically; its location can vary from the anatomic apex from the anatomic apex due to root morphology and distortion of the radiographic image. (apex locator or slob technique to determine the patency length)
• Crown-down preparation (step-down preparation) - A technique of canal preparation involving early flaring with instruments followed by incremental removal of canal debris and dentin from the orifice to the apical foramen; involves files with no apical pressure once binding occurs; variations have also been advocated, all of which emphasize cleaning and shaping of the coronal portion of the canal prior to the apical portion.
• Periapex- The anatomic site situated at and around the apical portion of a root
• Recapitulation- Reintroduction of small files during canal preparation to keep the apical area clean and patent