This document discusses the cleaning and shaping of root canals. It defines cleaning as the removal of pathogenic contents from the root canal and shaping as creating a 3D tapered shape that is widest coronally and narrowest apically. The objectives of shaping are outlined as both mechanical and biological to remove debris without forcing it periapically and create sufficient space for obturation. Various techniques are described such as step-back, crown-down, and hybrid techniques. Considerations like instrument movements, irrigation methods, and the goals of apical enlargement are also covered.
2. INTRODUCTION:
DEFINITIONS
Cleaning: removal of all potentially pathogenic contents
from root canal
Shaping: dual action – 3D prgogressive access
- apical prep to permit final obturation instruments &
materials to fit easily
OBJECTIVES
3. MECHANICAL OBJECTIVES:
1. CONTINUOUS TAPERING
CONICAL SHAPE
2. NARROW APICALLY AND
WIDEST CORONALLY
3. CONCEPT OF FLOW
(MULTIPLE PLANES)
4. APICAL FORAMEN AS
NARROW AS POSSIBLE
5. AVOID TRANSPOTATION
OF APICAL FORAMEN
4. BIOLOGICAL OBJECTIVES:
CONFINEMENT OF INSTRUMENT TO THE ROOTS
NECROTIC DEBRIS NOT FORCED PERIAPICALLY
COMPLETE REMOVAL OF TISSUE FROM THE
CANAL SPACE
CREATION OF SUFFICIENT SPACE FOR
OBTURATING MATERIAL
5. CLINICAL OBJECTIVES
Removal of overlying dentin straight line
access
Hermetic seal in obturation
Permanent restoration form function &
aesthetics
7. PRINCIPLES OF CANAL INSTRUMENTATION
STRAIGHT LINE ACCESS
PRECURVING
RETAINING ITS ORIGINAL FORM & SHAPE
IRRIGATION
RESTRICTING INSTRUMENTS WITHIN THE CANAL
RECAPITULATION
REMOVAL OF DENTINAL DEBRIS
8. PHASES IN SHAPING OF ROOT CANAL
I. NEGOTIATION (PATENCY FILING)
II. CORONAL PRE-ENLARGEMENT
III. WORKING LENGTH DETERMINATION
IV. SHAPING TECHNIQUES
V. WORKING WIDTH
9. PATENCY FILING
PRECURVED ISO SIZE 10 FILE / STAINLESS K FILE
REAMING MOTION
IN CALCIFIED CANALS OR WITH OBSTRUCTIONS, ISO SIZE 8
FILE OR SIZE 6 K FILE
CREATING A PATH PASSIVELY TO THE APICAL FORAMEN
HELPS IN MAINTAINING A CONTINUOUS & CLEAR PATH BY
REMOVING DEBRIS ESP. WHEN COMBINED WITH
IRRIGATION
10. CORONAL PRE-ENLARGEMENT
ADVANTAGES:
REDUCED POTENTIAL OF EXCRUCIATING DEBRIS
BEYOND APEX
APICAL GAUGING MORE ACCURATE
PREVENTS PREMATURE BINDING OF
INSTRUMENTS TO CANAL WALLS
BETTER IRRIGATION
3-4 MM INTO CANAL SPACE
ORIFICE ENLARGERS (NI-TI SYSTEM/ GG DRILLS)
13. TECHNIQUES
STEP BACK TECHNIQUE CROWN DOWN TECHNIQUE
CONVENTIONAL PRESSURELESS
PASSIVE DOUBLE FLARE
BALANCED FORCE
HYBRID TECHNIQUE
14. STEP BACK TECHNIQUE
No 10 & No 15 FILE INSERTED TILL WORKING
LENGTH; USE IN REAMING MOTION
APICAL ENLARGEMENT TO DEVELOP APICAL STOP
ATLEAST 3 SIZES (25 FILE SIZE)
INCREAZE FILE SIZE PROGRESSIVELY & WORKING
SHORT BY 1 MM
RECAPITULATION
AFTER PREPARING THE BODY OF CANAL, NOS 2 & 3
GATES GLIDEN DRILLS ARE USED FOR CORONAL
PREPARATION
CIRCUMFERENTIAL FILING USING MAF
15.
16. CROWN DOWN TECHNIQUE
CORONAL FLARING WITH GG DRILLS NO 2 OR 3
WITH EACH FILE BEING SEQUENTIALLY SHORTER
A LARGE FILE (SIZE 60) IS PLACED IN CORONAL
ASPECT & CANAL IS INSTRUMENTED IN WATCH
WINDING MOTION
SEQUENTIALLY SMALLER FILES TILL WORKING
LENGTH
APICAL ENLARGEMENT WITH MAF
FINAL TAPER WITH CIRCUMFERRENTIAL FILING
21. ULTRASONIC INSTRUMENTS
Richman
Cavitation & acoustic streaming
File movement 20,000-25,000 vibrations/second
Sodium hypochlorite – irrigation
Disadvg: over instrumentation
transportation of foramen
22. Cleaning & shaping
Step back technique
Filing & reaming motion
Sodium hypochlorite
irrigation
Apical enlargement- 3 sizes
beyond the first instrument
size used
Enlarge canal until healthy
dentine appears
Shaping & cleaning
Crown down tecnique
Balanced force movements
Chlorhexidine irrigation
EDTA for removal of smear
layer
Apical enlargement- as small
as possible
Depends upon-
o periapical pathology
o pulp-vital/infected/calcified
TRADITIONAL CONCEPT CURRENT CONCEPT