Resvision of endodontic principles

Question 1

What is Endodontology?

Answer 1

Endodontology is the study and treatment of the dental pulp and periradicular tissues, focusing on their health, injuries, diseases, prevention, and treatment, with apical periodontitis being the primary disease caused by infection.

Question 2

What causes endodontic disease?

Answer 2

Endodontic disease is primarily caused by microorganisms (bacteria), and host factors play a role in the progression of the disease.

Question 3

What are some common Gram-positive bacteria involved in endodontic infections?

Answer 3

Streptococcus species (strict anaerobe)
Oslenella uli (strict anaerobe)
Peptostreptococcus micros (strict anaerobe)
Lactobacillus species (facultative anaerobe)
Enterococcus faecalis (facultative anaerobe)

Question 4

What are some common Gram-negative bacteria involved in endodontic infections?

Answer 4

Gram-negative bacteria:
Treponema denticola (strict anaerobe)
Fusobacterium nucleatum (strict anaerobe)
Tannerella forsythia (strict anaerobe)
Dialister species (strict anaerobe)

Question 5

What is the difference between the apical region and coronal region in terms of bacterial infection?

Answer 5

Apical region: Low oxygen tension, fewer bacteria, and more difficult to treat due to less access to treatment methods.
Coronal region: Higher oxygen tension, more bacteria, and more accessible to treatment.

Question 6

What is biofilm in the context of endodontic disease?

Answer 6

Biofilm is an aggregation of microorganisms growing on a solid surface, embedded in a protective extracellular matrix. It makes bacteria more resistant to treatment and harder to remove mechanically.

Question 7

Why are biofilms resistant to eradication?

Answer 7

Biofilms create a physical barrier to antimicrobial agents, making penetration difficult. Additionally, biofilms have varying metabolic states, including slow growth and starvation survival, and can form persister cells that resist treatment.

Question 8

What does SOCRATES stand for in diagnosing endodontic disease?

Answer 8

SOCRATES is a mnemonic for systematic diagnosis:

S: Site
O: Onset
C: Character
R: Radiation
A: Associations
T: Time
E: Exacerbating/Relieving factors
S: Severity

Question 9

What is the difference between vitality and sensitivity tests in endodontics?

Answer 9

Vitality test checks whether the pulp is alive and functional.
Sensitivity test checks how the tooth reacts to stimuli such as cold or heat.

Question 10

What is the importance of using a rubber dam in endodontic treatment?

Answer 10

A rubber dam isolates the tooth, preventing contamination from saliva and improving visibility, patient comfort, and overall treatment success.

medicolegally and efficiency

Question 11

What is the goal of chemo-mechanical preparation of the root canal?

Answer 11

The goal is to clean and shape the root canal system, removing bacteria, debris, and necrotic tissue while optimizing irrigation and simplifying obturation (filling).

instruments shape
irritants clean
aim to produce shape that optimises irrigation and simplifies obturation

Question 12

What are Schilder’s design objectives for root canal preparation?

Answer 12

Continuously tapering funnel from apex to access cavity.
Maintain a narrower cross sectional diameter at every point apically.
Keep the apical foramen in its original position and as small as possible.

root canal preparation should flow with shape of original canal

Question 13

What are Schilder’s biological objectives for root canal preparation?

Answer 13

Confine instruments to the root itself.
Avoid forcing necrotic debris beyond the foramen.
Remove all tissue from the root canal space.
Create space for intracanal medicaments.
Preserve the root canal’s original anatomy.

Question 14

What are Morgan’s principles in root canal preparation?

Answer 14

The goal is to prepare a canal that can be properly irrigated and
obturated (filled),
leaving enough tooth structure to prevent fracture, while removing biofilm and debris.

Question 15

What are the challenges of automated instrumentation in endodontics?

Answer 15

Challenges include file fracture due to torsional failure or cyclic fatigue, and the use of rotary or reciprocating systems to properly shape the canal while avoiding procedural errors.

Question 16

What are common issues encountered during file manipulation in endodontic treatment?

Answer 16

File fracture due to torsional failure or cyclic fatigue.
Perforations, ledges, and transportation of the canal if incorrect techniques are used.

Question 17

What is the role of irrigants in chemo-mechanical preparation?

Answer 17

Irrigants are used to clean the root canal, flush out debris, and help remove biofilm. The right flow and choice of irrigant are crucial for effective cleaning.

Question 18

What is the importance of contemporary CBCT imaging in diagnosing endodontic disease?

Answer 18

CBCT (Cone Beam CT) provides detailed 3D images, allowing for better visualization of lesions that may not be visible with conventional radiographs. It is helpful for diagnosing and planning treatment, though the radiation dose must be considered.

Question 19

Why must multi-rooted teeth be considered carefully in endodontic diagnosis?

Answer 19

Multi-rooted teeth may give false positive or negative results in tests, so it is important to compare results with the contralateral (opposite) tooth for accuracy.

Question 20

What are the steps in diagnosing endodontic disease?

Answer 20

The diagnosis should be systematic and thorough, involving history, clinical examination, special tests, radiographs, and considering symptoms, clinical signs, and the results of vitality and sensitivity tests.

Question 21

: What is the role of isolation during endodontic treatment?

Answer 21

Isolation using a rubber dam is essential for preventing contamination, ensuring better visibility, increasing patient comfort, and improving the overall success rate of the treatment.

Question 22

What are step-back and modified double flare techniques in root canal preparation?

Answer 22

These are manual techniques for preparing the root canal. Step-back involves gradually increasing the size of instruments as you move from the apex to the access cavity. Modified double flare combines step-back and flaring techniques to create the proper shape.

Question 23

What are some problems with instrumentation during root canal treatment?

Answer 23

Problems include file fracture, ledges, perforations, and transportation. Proper technique and careful manipulation can minimize these issues.

Question 24

What is recapitulation in endodontics?

Answer 24

Recapitulation involves re-checking the master apical file to ensure it still reaches the working length after cleaning and shaping the root canal system.

Question 25

What are the biological objectives of root canal preparation according to Schilder?

Answer 25

These objectives include confining instruments to the root, removing all debris and necrotic tissue, creating space for medicaments, and preserving the root canal’s original anatomy.

Question 26

Name some file fracture issues

Answer 26

Torsional Failure: When the file twists too much and breaks. Cyclic Fatigue: Occurs when the file is subjected to repeated bending, causing it to break over time.

Question 27

Name automated instrumentation

Answer 27

Ni-Ti (Nickel-Titanium) Files: These files are less likely to cause errors like file fractures compared to stainless steel, due to their flexibility and strength. Rotary vs Reciprocating Systems: Both systems help in shaping the canal, but each has its own benefits depending on the clinical situation.

Question 28

Describe the Root canal mciorflroa

Answer 28

Planktonic Microorganisms: Free-floating bacteria in the canal. Biofilm: A community of microorganisms growing on a surface, embedded in a protective extracellular matrix. Complex Community: These microorganisms interact in complex ways and form biofilms, making them harder to eliminate.

Question 29

How do we diagnosis endodontic disease

Answer 29

tooth - palaptation ,percussion ,mobility test- endo ice ,heat ,EPT

Question 30

Question 31

hand isntuemtnaiton prep

Answer 31

Question 32

what is patency filling

Answer 32

- passing a small file 1mmm through apex to help remove debris and aid irritant flow

Question 33

What is direct pulp protection

Answer 33

- manage exposed surface if pulp using suitable material such as calcium hydroxide

Question 34

what re the causes of pulp exposure

Answer 34

- carious porcess -dentla trauma - iatrogenic

Question 35

What is pulpotomy

Answer 35

- invasive surgical procedure - removal of coronal portion of pulp tissue dressed with calcium hydroxide

Question 36

what is indirect pulp protection

Answer 36

- residual caries retained in close proximity to pulp without an actual breach. - cavity restored permanently with an adhesive, GIC/reisn composite

Question 37

what are the aims of a root canal prep

Answer 37

- remove microbes - remove pull remnants and organic debris - create an optimal shape to allow well compacted root filling - provide the optimal shape and resistance form for the root canal filling

Question 38

challenges in root canal prep

Answer 38

- isthmus - double or S shaped curvatures - cross section oval or ribbon - insutruemtns uniform - teeth have greater number of root canals than anticiptated MB have 2 - secondary nd tertiary dentine may result in partially calcified root canals .pulp stones and dystrophic calcifications - restricted mouth opening - position and angulation of the tooth may affect feasibility

Question 39

what is the working length

Answer 39

- length of root canal prep measured from suitable coronal reference point to the apical constriction - deterred by EAL technique and radiograph technique

Question 40

what is patency filling

Answer 40

- passive palcmenet of small hand file 0.5-1mm though apical cosntirciton during too tonal prep aim to prevent blockage of apical portion of the root canal by debris created during instrumentation. drawback - pottnetioal infected debris may be extruded into PA tissues - leading to post operative flare up

Question 41

SCHILDERS DESIGN OBJECTIVE

Answer 41

Remove all microbes Taper provide resistance and retention Continuous tapering funnel form apex to access cavity Cross sectional diameter should be narrower at every point apically Root canal prep should flow with shape of original canal Apical foramen in its original position Apical opening as small as possible Confine instrument to roots themselves No force necrotic debris beyond foramen Remove all tissue form root canal space Creation of sufficient space for intracanal medicaments

Question 42

MORGAN PRINCIPLES

Answer 42

IRRIGATE PROPERLY OBTURATE EASILY knock off BIOFILM EN ROUTE LEAVE TOOTH LEFT SO IT DOES not BREAK

Question 43

What is the purpose of hand instrumentation in endodontics?

Answer 43

To shape and clean the canal manually. Scouting: Use small files (e.g., size 8 or 10) to explore canal anatomy. Patency filing: Pass a small K-file just beyond the apex to prevent blockage, remove debris, and improve irrigant flow.

Question 44

What is the balanced force technique?

Answer 44

A method of file manipulation in curved canals using K-files. Sequence: Insert file with slight apical pressure. Rotate clockwise (¼ turn) to engage dentine. Then counter-clockwise (½–¾ turn) with apical pressure to cut dentine and advance file. Minimises transportation and preserves canal shape.

Question 45

What is stem-winding?

Answer 45

An outdated file manipulation method involving full clockwise rotation. Not recommended: higher risk of instrument fracture and canal distortion.

Question 46

What are the types of automated instrumentation?

Answer 46

Rotary systems: Continuous 360° rotation (e.g., ProTaper, WaveOne Gold rotary). Reciprocation systems: Alternating clockwise and counter-clockwise motion (e.g., WaveOne Reciproc). Both use NiTi files for flexibility and canal centering ability.

Question 47

Compare NiTi and stainless steel files.

Answer 47

NiTi files: Greater flexibility – better for curved canals. Less canal transportation. Risk of cyclic fatigue and torsional failure. Stainless steel files: Rigid, cause more canal distortion. Less likely to fracture due to fatigue.

Question 48

What is cyclic fatigue in NiTi files?

Answer 48

Repeated tension-compression cycles in curved canals cause microscopic cracks → eventual fracture. Worse in canals with: Sharp (small radius) curves Thicker, stiffer files Prevention: Avoid binding files. Use files for limited number of canals. Continuous movement of the file.

Question 49

What is torsional failure in NiTi files?

Answer 49

Occurs when the tip binds in the canal but the shaft continues rotating → torsional stress → fracture. Prevention: Avoid forcing the file. Use light pressure. Always create a glide path beforehand.

Question 50

How can you avoid instrument fracture during automated instrumentation?

Answer 50

Use glide path first (e.g., size 10 or 15 K-file). Respect canal curvature – consider angle and radius of curve. Use flexible, thinner NiTi files in curved canals. Keep the file moving – avoid prolonged engagement. Do not force files into tight canals (prevents torsional failure). Use appropriate torque settings on motor.

Question 51

Describe the role of radiographs in the diagnosis of endodontic disease. (10 marks)

Answer 51

1. Detection of periapical pathology Identify radiolucencies indicating periapical periodontitis or abscesses. 2. Assessment of pulp and periapical tissues Assess vitality indirectly (e.g., calcified canals, internal/external resorption, widened periodontal ligament space). 3. Visualisation of caries and restorations Detect deep carious lesions, defective restorations or recurrent caries that may have caused pulpal involvement. 4. Evaluation of root and canal morphology Assess number, curvature, and shape of roots and canals to anticipate treatment complexity. 5. Detection of previous endodontic treatment Identify quality of previous obturation, missed canals, short/overextended fillings, and presence of posts. 6. Diagnosis of fractures or trauma Detect root fractures, horizontal or vertical, and traumatic injuries such as luxation or avulsion. 7. Aid in treatment decision Helps determine whether a tooth is restorable, and if endodontic treatment is feasible or if extraction is needed. 8. Baseline record for comparison Acts as a reference point to monitor healing or disease progression later. 9. Limitations 2D image of a 3D structure; early bone loss may not be visible immediately. 10. Complementary to clinical findings Should always be interpreted alongside clinical tests (e.g., percussion, vitality testing) for accurate diagnosis.

Question 52

When radiographs are taken during root canal treatment and their purpose at each stage:

Answer 52

📸 1. Pre-operative Radiograph (Before Treatment) When? Before starting treatment. Purpose: Diagnose pulpal and periapical disease Assess root and canal anatomy Identify complexities (e.g. curved roots, resorption, previous RCT) Evaluate restorability of the tooth 📸 2. Working Length Radiograph (During Treatment) When? After canal scouting and establishing working length (if not using apex locator alone). Purpose: Confirm correct canal length Avoid over-instrumentation (beyond apex) or under-instrumentation (short of apex) Ensure files/gutta-percha cones are at proper working length 📸 3. Master Cone Radiograph (Before Obturation) When? After canal preparation and before obturation. Purpose: Confirm gutta-percha cone fits to working length Check for tug-back and adaptation at the apex Assess if obturation material will fill canal adequately 📸 4. Post-Obturation Radiograph (Immediately After Filling) When? Right after root canal filling and sealer placement. Purpose: Assess obturation quality: length, density, voids Check for extrusion of sealer or gutta-percha Provide a baseline image for follow-up 📸 5. Follow-Up Radiographs (6–12 Months Post-Treatment) When? After 6–12 months, sometimes yearly for up to 4 years. Purpose: Assess healing of periapical tissues Ensure no signs of reinfection or pathology Compare with baseline post-op image ✅ Optional/Additional Radiographs Mid-treatment radiographs if: Treatment is done over multiple visits There is a change in clinical findings A procedural complication (e.g. file separation, ledge) is suspected CBCT scan: For complex cases, retreatment, or unclear diagnoses (e.g. missed canals, fractures)