Cleaning and shaping

Cleaning and shaping of root canal

1. CLEANING AND SHAPING OF ROOT CANAL SYSTEM Presented by: Rheia Baijal 3271 BDS Final Year

2. INTRODUCTION

3. What Is Cleaning And Shaping ? Cleaning - It comprises the removal of all potentially pathogenic contents from the root canal system. Shaping - It is the establishment of a specifically shaped cavity which performs the dual role of- three dimensional access into canal Creating an apical preparation which will permit the final obturation instruments to fit easily.

4. Objectives of Root Canal Preparation (given by Schilder ) MECHANICAL OBJECTIVES BIOLOGICAL OBJECTIVES CLINICAL OBJECTIVES

5. MECHANICAL OBJECTIVES The root canal preparation should develop a continuously tapering cone. Making the preparation in multiple plane which introduces the concept of “FLOW.” Making the canal narrow apically and widest coronally . Avoid transportation of foramen. Keep the apical opening as small as possible.

6. BIOLOGICAL OBJECTIVES

7. CLINICAL OBJECTIVES Removal of overlying dentine causes smooth internal walls and provide straight line access to root canals After obturation there should be complete sealing of the pulp chamber and access cavity so as to prevent microleakage . Tooth should be restored with permanent restoration to maintain it’s form,function and esthetics and patient should be recalled on regular basis for evaluation Removal of overlying dentine causes smooth internal wallls and provide straight line access to root canals

8. INSTRUMENTS USED FOR RADICULAR PREPARATION LASERS Automated (sonic/ultrasonic)

9. DIFFERENT MOVEMENTS OF INSTRUMENTS

10. Reaming 1)Reaming action : It is a repeated clockwise rotation of the Instrument which will shave the canal walls and give a cross sectional preparation approximately round. Reamers are usually more effective for this function

11. Filing 2 ) Filing action : It is a push pull action without rotation which has a great efficiency with files than reamers. The cross sectional appearance of the prepared root canal is irregular with general oval configuration.

12. Combination Of Reaming And Filing 3) Combination: In this technique file is inserted with a quarter turn clockwise and apically directed pressure & then is subsequently withdrawn .

13. Balanced force technique Insertion -Clockwise 60 degree Apical pushing with rotation of 120 degree counter clockwise Removal by giving a 60 degree rotation clockwise

14. Watch Winding 5 ) Watch-winding motion . Arched arrow indicates a gentle right and left rocking motion, which causes the instrument to cut while a light inward pressure (straight arrow) keeps the file engaged and progressing toward the apex. Arc of rotation is indicated by the shaded region in the circle . 30 degrees each way.

15. Watch Winding And Pull Motion 6) Watch-winding-and-pull motion. This is used primarily with Hedström files. 1, Inward pressure is maintained (straight arrow), while the file is gently rocked right and left, through the arc indicated by the shaded region of the circle; 2, when insertion stops, all rotation is ceased and the instrument is withdrawn .

16. Motions Of Instruments For Cleaning And Shaping There are six unique motions of files and reamers used in serial shaping, they are follow, follow-withdraw, cart, carve, smooth, and patency. 1. Follow - In this file is pre curved to follow canal curvatures. 2.Follow withdraw -In and out motion is given to the instrument.It is done to create a path for foramen. 3.Cart - Carting actually means transporting, refers to the extension of a reamer to or near the radiographic terminus. The precurved reamer should gently and randomly touch the dentinal walls at the radiographic constriction and "cart" away dentinal debris and pulp remnants 4 .Carve- Carving is for shaping. The key is not to press the instrument apically but simply snuggle into the dentin with a precurved reamer and shape on withdrawal. 5 .Smooth -Smoothing is circumferential filing, is usually accomplished with files . 6 . Patency – it is achieved with files or reamers. It means simply that the portal of exit has been cleared of any debris in its path.

17. Basic Principles Of Canal Instrumentation There should be a straight line access to the root canal system. Copius irrigation should be done in between instrumentation. Prepared canal should retain it’s original form and shape Exploration of orifice should be done with smaller file to gauge the canal size and configuration Canal enlargement should be done using instruments in sequential order. Flutes should be cleaned and inspected after each removal. Never force the instrument in the canal Recapitulation is regularly done to loosen debris. Over preparation and too aggressive over enlargement of curved canals should be avoided. Overusing of larger files must be avoided as it may result in further enlargement of apical opening.

18. Techniques Of Root Canal Preparations Two approaches for biomechanical preparation Apical to coronal technique B Coronal to apical technique

19. VARIOUS OTHER TECHNIQUES HAVE BEEN MODIFIED OUT OF THESE TWO BASIC TECHNIQUES : apical to coronal STANDARDISED TECHNIQUE OF CANAL PREPARATION STEP BACK MODIFIED STEP BACK TECHNIQUE PASSIVE STEP BACK TECHNIQUE Coronal to apical STEP DOWN CROWN DOWN PRESSURELESS HYBRID TECHNIQUE OF CANAL PREPARATION BALANCED FORCE TECHNIQUE REVERSE BALANCED FORCE PREPARATION DOUBLE FLARE TECHNIQUE MODIFIED DOUBLE FLARE TTECHNIQUE

20. Standardized Preparation Technique

21. STEP BACK TECHNIQUE

22. CROWN DOWN TECHNIQUE- Phase 1 Evaluate Tooth decay causing pulp exposure Prepare the access cavity and locate canal orifice

23. Placement of file to working length

24. Remove intrumnt and irrigate the canal. Recaptiulation using smaller file 25 no. file at working length

25. Phase 2

26. 30 No file 1 mm short of working lenght 35 no file 2mm short of working length 40 No file 3mm short of working length

27. 45 No. file 4mm short of working length 50mm file for canal preparation

28. Step Back preparation creates small apical preparation with larger instruments used at successively decreasing lengths to create a taper

29. Variations in step back technique Enlargement of coronal part of canal using GG drills Use of smaller GG drills to prepare mid root level

30. Advantages And Disadvantages Advantages More flare at corornal part of the root canal with proper apical stop. Disadvantages Difficult to irrigate apical region Chances of pushing debris apically. Time consuming Iatrogenic errors like ledge formation in curved canals may occur Difficult to penetrate instruments in canal More chances of instrument fracture

31. Modified step back technique

32. Passive Step Back Technique

33. Crown Down Technique

34. Steps Straight line access to root canal system Access cavity is filled with irrigant

35. Preflaring of Coronal third of Canal using GG Drill (larger first smaller subsequently) Excessive use of GG drill at same level leads to excessive cutting of dentine weakening of roots and there by coke bottle appearance in radiograph Establish working length with small instrument after irrigation and recapitulation.

36. Use of larger file to prepare coronal third. Preparation of canal at middle third with subsequently smaller no. of file. Apical preparation of canal with frequent irrigation of canal system

37. Well Prepared tapered preparation of the tooth.

38. Balanced Force Technique Positioning and preloading an instrument through a CW rotation & then shaping the canal with a CCW rotation Flex-R file

39. Balanced Force Technique Engaging dentine with a light quarter-clockwise turn.  (60 degree) The cutting stroke - turning CC 120 degree and pushing apically to prevent it from backing out of the canal Clearing cutting debris requires another light quarter-clockwise turn of 60 degree

40. Step Down Technique ADVANTAGES

41. Hybrid technique Combination of step back and crown down technique Uses both rotary and hand insrtuments Hand instruments secure a patent glide path Tapered rotary instruments efficiently enlarge coronal canal areas

42. DOUBLE FLARED TECHNIQUE

43. Modified Double Flare technique

44. ENGINE DRIVEN ROTARY INSTRUMENTS Rotary with alternating cutting alternating cutting edges

45. Canal Preparation Using Ultrasonic Instruments Suggested by Richman Movement of file shaft between 0.001-0.004 inch at 20000- 25000/sec frequency . For free movement of file in canal it should Not have any binding specially at apical end.

46. Technique

47. MECHANISM OF ACTION Ultrasonic cavitation and implosion

48. Thank - You