Anatomy...Acess...Canal Prep Flashcards
What should you think of when you think Anatomy?
- Think 3-D!
- Expectations
- Variations
- Coronal, chamer, canal, apical
What does the Law of Centrality state?
Pulpal floor always located in center of tooth at level of CEJ
What does the law of the CEJ state?
The CEJ is the most consistent, repeatable landmark for locating the position of pulp chamber
What does the law of Concentricity State?
The walls of the pulp chamber are always concentric to external surface of the tooth at level of the CEJ
What does the first law of symmetry state?
Except for max molars, orifices are equidistant from a line draw in a MD direction through the pulpal floor
What does the second law of symmetry state?
Except for max molars; Orifices lie on a line perpendicular to a line drawn in MD direction across center of pulpal floor
What is the Law of color change?
The color of the pulp chamber floor is always darker than walls
What are the 3 laws of Orifice Location?
- The orifices are always located at junction of walls and floor
- The orifices are located at angles of floor-wall junction
- The orifices are located at terminus of root developmental fusion lines
Describe the 4 Weine Classifications…
How many canals does a Maxillary Anterio typically have?
How many canals does a Mandibular Anterior Tooth typically have?
What % do Mandibular Canines have 2 canals?
22%
How many canals does a Maxillary Premolar typically have?
Which pre-molar is the 50/50 tooth?
Max 2nd Premolar
How many canals does a Mandiblar Premolar typically have?
Which pre-molar has a 97% chance of having 1 canal?
Mandibular 2nd Premolar
How many canals does a Maxillary 1st Molar typically have?
What is the % chance there will be MB2 in Max 1st Vs Max 2nd Molars?
- 1st Molar: 1 canal 20%, 2 canals 77%, 3 canals 3%
- 2nd Molar: 1 canal 63%, 2 canals, 37%
How many canals does a Mandiblar Molar have typically?
Which tooth is likely to have a “C” shaped canal?
Mandibular 2nd Molar, 3%
Describe Straight-Line Access…
- Improves vision
- Reduces curvature
- Facilitates instrumentation & Obturation
- Immproves instrument control
Fewer misadventures
Why might it be wise to access without a RD?
- Ensure correct toth
- Visulize long axis - facilitate correct approach
How do you arrive at an appropriate working length?
- Estimate
- Radiogaph (0.5 - 1.0 mm)
- Tactile sense
- Electronic Apex Locator
- Paper Point
- Patient Sensation
What is the average surface to constriction?
What is the aerage deviation major to apex?
- Avg to constriction 0.75
- Avg deviation major to apex 0.59
Describe this picture…
Major foramen is larger than minor formaen at constriction - looking from the external root surface apex
Describe how a Root ZX works?
- “Ratio method”
- Simultaneously measures impedance of two different frequencies, calculates the quotient of the impedances, and expresses this quotient as a position of the file inside the root canal
- No calibration required
- Small files and large files yield similar readings
- Rootz ZX identifies narrowest canal diameter even wen an anatomic apical constriciton did not exist of was destoryed by instrumentation
What are the objectives of Cleaning & Shaping?
- Total removal of content of pulp space (tissue, debris, bacteria, byproducts)
- Develop straight line access to apical region
- Maintain central axis of canal
- Keep apical constriction small and in original position
- Continuously tapering, smooth, funnel-shaped preparation
What type of hand file is this?
- Flex R
- K-Reamer (large)
- K-File (large)
What type of hand file is this?
- K-Flex (small)
- K-Reamer (small)
- K-File (small)
What type of Hand File is this?
- K-Flex (large)
What type of hand file is this?
Hedstrom
What type of hand file is this?
- Unifile
- S-File
What is the Material/Cross-Section/Tip Design of K-File?
Hand File…
- Material: SS
- Cross - Section: Triangular/Square
- Tip Design: Cut
What is the Material/Cross-Section/Tipe design of the hand file K flex?
- Material: SS
- Cross - Section: Rhomboid
- Tip Design: Cut
What is the Material/Cross-Section/Tip Desing of Hand File Flex-R?
- Material: SS
- Cross-Section: Triangular
- Tip Design: Safe
What is the Material/Cross-Section/Tip Design for Sureflex Hand Files?
- Material: NiTi
- Cross Section: Square
- Tip Design: Safe
Describe the Increase in Diamter in this .02 tapered file?
0.32 mm Increase in Diameter from DO to D16
Describe the Increase Diameter in the .04 tapered file below…
0.64 mm Increase in Diamter from DO to D16
What is Rake Angle?
What are the 2 types of Rake Angles?
- Negative Rake
- Positive Rake
What is the difference between a Scapre and Cut Rake Angle?
In the middle of these is planning with the blade faced down…
Describe the Rake on this K3 Niti File that you use…
- K3: Assymetric flutes separated by lands.
- Positive rake angle
- More resistant to fracture
What are some Advantages of a NiTi Rotary Instrumentation System?
- Speed
- Less fatigue
- Costly
- Learning Curve
- Design pulls debris out
- Flexible
- Less transportation
- Fracture resistant
What are 2 instruments for shaping orifices?
- Gates Glidden: Drills Sizes 1-6
- Peeso Reamers: Sizes 1-6
Why use Chemical Disinfection if you are instrumenting the canal system?
- All aspects of a canal system cannot be reached by files
- Need some method to further clean these spaces
Describe 8% (Full Strength) NaOCl…
- Gold Standard
- Dissolves necrotic tissue
- Removes the organic portion of smear layer
- Germicide
- Detoxifies Endotoxins
- Lubricant
- Bleaching Agent
- Deordorizer
*Dilution reduces all beneficial effects!
What will 2% Chlorhexidine Gluconate not do?
Dissolve Tisue!
* Alternative endodontic irrigant for sodium hypochlorite allergic patients
What is the % associated with EDTA?
17%
Describe some attributes of 17% EDTA…
- Chelating agent
- Lubricant
- Help remove inorganic portion of smear layer
- Ethylenediaminetetracetic Acid
What is this?
Smear Layer
What type of needle is ideal for delivering Intracanal Irrigation?
What are some characteristics of Calcium Hydroxide?
- High pH…Alters Environment
- Antimicrobial
- Dissolves tissue
- Favors calcification (alkaline phosphatase formation)
- Favros osteogenesis
- Causes limited tissue necrosis…elicits healing response
- Helps dry “weeping” canals
- Halts or slow resorptive processes
- Effective for 1 week
Describe how Alkaline Phosphatase leads to dentin bridge formation?
