EVIDENCE-BASED    APPROACH TOROOT CANAL CLEANING    AND SHAPING      INDIAN DENTAL ACADEMY   Leader in Continuing Dental E...
•   Introduction•   What is Evidence Based Dentistry?•   What is cleaning and shaping??•   History of cleaning and shaping...
IntroductionEndodontic treatment is divided into  3 main phases• Bio mechanical preparation• Disinfection• ObturationThe f...
What is Evidence Based           Dentistry ??The foundation for Evidence Based practice was  laid by David Sackett who has...
What is   Cleaning and Shaping??Major Objective of root canal treatment is to remove the contents of the canal and adjacen...
History of Cleaning and           Shaping1893 - Emil Schreier/Vienna -mixture of alkali  metals for cleaning and disinfect...
Principles of Endodontic Cavity               Preparation    Coronal cavity preparation I. Outline form II. Convenience f...
Objectives of Cleaning and          Shaping• Biologic   To free the root canal from pulp, bacteria and their  endotoxins• ...
Traditional cleaning and  shaping breakdowns WORKING SHORT APICAL PREPARATION FIRST INSTRUMENTS AND METHODS OF  USE    ...
Armamentarium for canal        preparation Instruments Cleaning reagents, Devices and Indicators           www.indianden...
Instruments used for      canal preparation Broaches Hand Instruments Rotary NiTi Instruments          www.indiandental...
Endodontic Hand            Instruments Files Reamers Hedstroems NiTi Hand Files            www.indiandentalacademy.com
Hand Files• K files                     • K flex files• Square blanks with          • Diamond shaped  90o                 ...
Hand Files• Reamers• Triangular blanks,60o• Clockwise reaming action            www.indiandentalacademy.com
Hand Files• Hedstroems• H style modifications include S file and U  file• E. Schafer et al determined that  Hedstroem file...
Hand Files• NiTi Hand Files• NiTi K hand files, NiTi Mac hand files , NiTi  Hedstroem files, NiTi flex R hand files, NiTi ...
NiTi Rotary Instruments Light speed Profile Quantec Flexmaster ProTaper Race K3 Mtwo                www.indiandent...
Terminologies used• Rake angle Angle formed by the cutting edge and the  cross section taken perpendicular to the  long a...
Terminologies used•   HELICAL ANGLE   Angle that the cutting edge makes with    the long axis of the file   Varying Angl...
Terminologies used• PITCH Pitch refers to the number of flutes per unit  length Constant pitch Variable pitch          ...
Terminologies used• RADIAL LANDS Surfaces that project axially from the  central axis between the flutes Flat : Profile,...
NiTi Rotary Instruments Light speed Short flame shaped Reduced diameter  shaft Decreased incidences  of canal  transpo...
NiTi Rotary Instruments Profile                          Profile GT Tri helical, symmetric,         • Same U shaped  U ...
NiTi Rotary Instruments Quantec                        K3 Wide radial land                                 Positive ra...
NiTi Rotary Instruments Flexmaster Round passive tips High percentage of instrument fractures Extended Working time I...
NiTi Rotary Instruments Protaper (progressive Race                        (Reamer with  taper)                          ...
NiTi Rotary Instruments•   Mtwo•   S shaped cross sectional design•   Positive rake angle with 2 cutting edges•   Increasi...
NiTi Rotary Instruments     www.indiandentalacademy.com
Physical and Chemical            properties of NiTi•              Instruments    Heat, probably during sterilization cycle...
Physical and Chemical        properties of NiTi•           Instruments modes: Instruments break in 2 distinct Torsional ...
Cleaning reagents, Devices and             Indicators• Ideal irrigant Kills bacteria and inactivates endotoxins Dissolve...
Sodium Hypochlorite• Effective against Enterococcus, Actinomyces  and Candida organisms• Various concentrations range from...
Sodium Hypochlorite• To increase the efficacy of NaOCl Lower the pH Increase the temperature Ultrasonic activation of s...
Chlorhexidine• Broad spectrum Antibiotic• Its use as an endodontic irrigant is based on its substantivity Binding to Hyd...
Chlorhexidine• CHX + Ca(OH)2 show strong antibacterial  activity against obligate anaerobes• CHX did not affect the alkali...
Iodine Potassium Iodide• IKI kills a wide spectrum of micro  organisms• Low toxicity• Acts as an oxidising agent against  ...
M T A D• Mixture of Tetracycline isomer (doxycycline),  Acid (citric acid), Detergent (tween 80)• Removes smear layer• Mor...
E D T A• Forms stable calcium complex with dentin  mud, smear layer and calcific deposits and  prevent apical blockage• Ne...
E D T A• Calcium binding releases protons and EDTA  loses efficiency in acidic environment• Effervescence or bubbling effe...
Other Irrigants used• Calcium Hydroxide (requires prolonged  exposure)• Hydrogen Peroxide• Salvizol (N1-decamethylene- bis...
Suggested Irrigation          Regimen• Hypochlorite solution should be employed  throughout instrumentation without alteri...
Suggested Irrigation          Regimen [continued]• Once shaping is completed canals can be thoroughly  rinse with EDTA for...
Alternative concepts• Use of Laser light• Electrochemically activated water• Ozone gas infiltration  None of these approac...
Indicators• Ruddle Solution/Visualisation Endogram 5% NaOCl Hypaque 17% EDTA• Clinicians use Endograms to visualize  mi...
Ultrasonics• Ultrasonics use sound as an energy source resulting in a  three dimensional activation of the file• Alternati...
Ultrasonics• Druttman and Stock pointed out, "with the  ultrasonic method, results depended on  irrigation time. “The clea...
Ultrasonics• Guys Hospital in London pointed out that acoustic streaming  "depends on free displacement amplitude of the f...
Sonics• Sonic systems uses vibration in audible  frequency range for activation of endodontic files• Three sonic files use...
Sonics• Dummer et al the Shaper Sonic files widened the canals  more effectively than the Rispi Sonic files, whilst the Tr...
Position of the apical               foramen • Traditional treatment has held that canal   preparation and subsequent obtu...
Factors related topreparation length                   • Use of a patency file                   • Apical width  www.india...
Patency File• Small K File (#10 size or #15 size) that is passed  through the foramen• Suggested for most rotary technique...
Apical Width• Position of apical constriction and diameter is  difficult to assess clinically• Some have recommended gaugi...
Narrow Apical             preparations• Benefits Minimal risk of canal transportation, extrusion of  irrigants, or extrus...
Wide Apical preparations• Benefits• Removal of infected dentin• Access of irrigants and medications in  apical third of ro...
• Despite the disagreement it appears that  the root canal preparation• should be confined to the canal space• should be s...
Canal Preparation          Techniques• Various instrumentation techniques  developed for Hand and Rotary  instruments• Sha...
Techniques for Canal         Instrumentation•   Traditional step back technique•   Crown down technique•   Apical widening...
Step Back/Telescopic          technique• Traditional cleaning and shaping strategy• Initial preparation of the apical thir...
Step Back/Telescopic•              technique    Determine working  length• Serially develop an  apical stop• Step back  pr...
Crown Down/Step down          technique• Most rotary techniques require a crown down  approach• Minimizes torsional loads•...
Crown Down/Step down          technique• Step apically by using  a series of files while  decreasing instrument  size or i...
Crown Down/Step down      technique    www.indiandentalacademy.com
Crown Down Pressureless          technique• Similar to crown down concept• Rotate straight files 2 times in a clockwise  d...
Balanced Force technique• Roane et al described this technique1. Using a Flex K file/Flex R file, the instrument is   rota...
Hybrid Instrumentation• Ideal preparation for the hybrid concept  takes its pattern from the definition by  Herbert Schild...
Hybrid/Double Flared           technique• All the basic techniques combined to eliminate  the short comings of individual ...
Benefits of Hybrid          technique• Instruments can be used in a manner that  promotes their individual strengths• Hand...
8 step technique• Enlargement of coronal third with K/H  files/rotary/GG• Working Length determination• Enlargement of api...
Rotary Instrumentation• Light speed instrumentation          www.indiandentalacademy.com
Rotary Instrumentation     www.indiandentalacademy.com
Rotary Instrumentation• Profile instrumentation          www.indiandentalacademy.com
Rotary Instrumentation• Protaper instrumentation          www.indiandentalacademy.com
Hybrid Instrumentation     www.indiandentalacademy.com
Hybrid Instrumentation     www.indiandentalacademy.com
Hybrid Instrumentation     www.indiandentalacademy.com
Hybrid Instrumentation     www.indiandentalacademy.com            DCNA48;197,2004
Non Instrumentation            Technique• Lussi and his associates at the University of Bern,  Switzerland, introduced dev...
Non Instrumentation•                  Technique the device    More recently, they have improved    and reported that the "...
Laser assisted Canal           preparation• Levy G et al -the Nd:YAG, in combination with  hand filing, is able to produce...
CONCLUSION• Clinically, it is important to envisage the shaping  procedure extending beyond antimicrobial  efficacy• Altho...
www.indiandentalacademy.com www.indiandentalacademy.com
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EVIDENCE-BASED APPROACH TO ROOT CANAL CLEANING AND SHAPING / /certified fixed orthodontic courses by Indian dental academy

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EVIDENCE-BASED APPROACH TO ROOT CANAL CLEANING AND SHAPING / /certified fixed orthodontic courses by Indian dental academy

  1. 1. EVIDENCE-BASED APPROACH TOROOT CANAL CLEANING AND SHAPING INDIAN DENTAL ACADEMY Leader in Continuing Dental Education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. • Introduction• What is Evidence Based Dentistry?• What is cleaning and shaping??• History of cleaning and shaping• Objectives• Armamentarium• Techniques of canal instrumentation• Non instrumentation technique www.indiandentalacademy.com
  3. 3. IntroductionEndodontic treatment is divided into 3 main phases• Bio mechanical preparation• Disinfection• ObturationThe first step for effective BMP is straight line accessNext step is exploration of the canal, extirpation of remaining pulp tissues and gross debridement of necrotic tissuesFollowed by proper instrumentation, irrigation and debridement and disinfection of the root canal www.indiandentalacademy.com
  4. 4. What is Evidence Based Dentistry ??The foundation for Evidence Based practice was laid by David Sackett who has defined it as“Integrating individual clinical expertise with the best available external clinical evidence from systemic research” Evidence based dentistry; DCNA; Vol 46;no 1:Jan 2002 www.indiandentalacademy.com
  5. 5. What is Cleaning and Shaping??Major Objective of root canal treatment is to remove the contents of the canal and adjacent tissues in such a way that filling procedures that follow will be facilitated….To describe this aspect of treatment lucidly, Schilder has dubbed these procedures Cleansing and Shaping in emphasis of the need for the debridement and development of a specific receptacle for the filling material www.indiandentalacademy.com
  6. 6. History of Cleaning and Shaping1893 - Emil Schreier/Vienna -mixture of alkali metals for cleaning and disinfecting root canal1894 - Dr Callahan/Cincinnati used Sulphuric acid within canals to clean root canals1900 - Dr Harlan -Papain for digesting dead tissues1917 - Dr Hermann Prinz - 1% sodium chloride during electromedication1941 - Dr Louis Grossman - 5.25% sodium hypochlorite dissolved pulp tissue in vitro www.indiandentalacademy.com
  7. 7. Principles of Endodontic Cavity Preparation Coronal cavity preparation I. Outline form II. Convenience formIII. Removal of remaining carious dentinIV. Toilet of cavity Radicular cavity preparation I. Outline / Convenience formIV. Toilet of cavity V. Retention formVI. Resistance form www.indiandentalacademy.com
  8. 8. Objectives of Cleaning and Shaping• Biologic To free the root canal from pulp, bacteria and their endotoxins• Mechanical A continuously tapering preparation Original anatomy maintained Position of the foramen maintained Foramen as small as is practical www.indiandentalacademy.com
  9. 9. Traditional cleaning and shaping breakdowns WORKING SHORT APICAL PREPARATION FIRST INSTRUMENTS AND METHODS OF USE www.indiandentalacademy.com
  10. 10. Armamentarium for canal preparation Instruments Cleaning reagents, Devices and Indicators www.indiandentalacademy.com
  11. 11. Instruments used for canal preparation Broaches Hand Instruments Rotary NiTi Instruments www.indiandentalacademy.com
  12. 12. Endodontic Hand Instruments Files Reamers Hedstroems NiTi Hand Files www.indiandentalacademy.com
  13. 13. Hand Files• K files • K flex files• Square blanks with • Diamond shaped 90o blank,80o• Rasping/Filing motion • Greater flexibility www.indiandentalacademy.com
  14. 14. Hand Files• Reamers• Triangular blanks,60o• Clockwise reaming action www.indiandentalacademy.com
  15. 15. Hand Files• Hedstroems• H style modifications include S file and U file• E. Schafer et al determined that Hedstroem files had better cutting efficiency than S or U files www.indiandentalacademy.com IEJ 1996, 29, 302-08
  16. 16. Hand Files• NiTi Hand Files• NiTi K hand files, NiTi Mac hand files , NiTi Hedstroem files, NiTi flex R hand files, NiTi U hand files, NiTi X Hand Files, NiTi S Hand files• G. Nagy et al concluded that NiTi K-files produced more appropriate shapes in the roots with apical curved canals than NiTi S-files IEJ 2002, 35, 283-88. www.indiandentalacademy.com
  17. 17. NiTi Rotary Instruments Light speed Profile Quantec Flexmaster ProTaper Race K3 Mtwo www.indiandentalacademy.com
  18. 18. Terminologies used• Rake angle Angle formed by the cutting edge and the cross section taken perpendicular to the long axis of the instrument POSITIVE RAKE ANGLE:Hero 642,K3 NEGATIVE RAKE ANGLE: Profile, Protaper, Quantec, Lightspeed , RaCe www.indiandentalacademy.com
  19. 19. Terminologies used• HELICAL ANGLE Angle that the cutting edge makes with the long axis of the file Varying Angle: Protaper, Quantec, K3, RaCe Constant Angle:Profile, Hero 642, and Lightspeed www.indiandentalacademy.com
  20. 20. Terminologies used• PITCH Pitch refers to the number of flutes per unit length Constant pitch Variable pitch www.indiandentalacademy.com
  21. 21. Terminologies used• RADIAL LANDS Surfaces that project axially from the central axis between the flutes Flat : Profile, GT Recessed : Quantec Combination : K3 www.indiandentalacademy.com
  22. 22. NiTi Rotary Instruments Light speed Short flame shaped Reduced diameter shaft Decreased incidences of canal transportation www.indiandentalacademy.com
  23. 23. NiTi Rotary Instruments Profile  Profile GT Tri helical, symmetric, • Same U shaped U shaped flutes designs incorporated separated by lands • Greater tapers Constant pitch available Instrument becomes • Variable pitch rather stiff before apical preparation has been sufficiently enlarged www.indiandentalacademy.com
  24. 24. NiTi Rotary Instruments Quantec  K3 Wide radial land  Positive rake angle, wide Safe cutting tip is radial lands and a specially designed for peripheral blade for small, narrow canals and reduced friction calcified canal systems  Shaping ability similar to that of ProTaper www.indiandentalacademy.com IEJ 36:288,2003
  25. 25. NiTi Rotary Instruments Flexmaster Round passive tips High percentage of instrument fractures Extended Working time Increased risk of transportation OOOOE 101:807,2006 www.indiandentalacademy.com
  26. 26. NiTi Rotary Instruments Protaper (progressive Race (Reamer with taper) Alternating Cutting Edges) Modified K Type file with  utilizes an “alternating sharp cutting edges and helical design” that no radial lands: Stable reduces rotational torque core sufficient flexibility by using spiraled and non Wide canals insufficiently spiraled portions along prepared the working length  prevent threading or blocking effect www.indiandentalacademy.com IEJ 36:86,2003/OOOOE 101:807,2006
  27. 27. NiTi Rotary Instruments• Mtwo• S shaped cross sectional design• Positive rake angle with 2 cutting edges• Increasing pitch length• Prepared curved canals rapidly• Respected original canal curvature well• Safe to use• Remained better centered than K3 and Race IEJ,39;196,2006 www.indiandentalacademy.com
  28. 28. NiTi Rotary Instruments www.indiandentalacademy.com
  29. 29. Physical and Chemical properties of NiTi• Instruments Heat, probably during sterilization cycles could even restore the molecular structure of NiTi (Nickel Titanium instruments: Applications in endodontics)• Sterilization procedures are safe and produced a significant increase in fatigue resistance of the instruments (IEJ 39,709;2006)• Cryogenic treatment resulted in microhardness but this increase was not detectable clinically(IEJ,38,364,2005)• Linear deforming forces shunted into stepwise transformation from austenitic to martensitic form-leads www.indiandentalacademy.com of 7% to elastic deformation
  30. 30. Physical and Chemical properties of NiTi• Instruments modes: Instruments break in 2 distinct Torsional Flexural• NiTi can withstand several hundred flexural cycles before they fracture• Torque depends on contact area and axial pressure• Crown down approach is recommended to prevent taper lock IEJ 35:379,2002/IEJ 32:24,1999/IEJ 34:471,2001 www.indiandentalacademy.com
  31. 31. Cleaning reagents, Devices and Indicators• Ideal irrigant Kills bacteria and inactivates endotoxins Dissolves necrotic tissue Lubricates the canal Removes the smear layer Does not irritate healthy tissues IEJ 36:538,2001/JoE32;5;2006 www.indiandentalacademy.com
  32. 32. Sodium Hypochlorite• Effective against Enterococcus, Actinomyces and Candida organisms• Various concentrations range from 0.5% to 5.25%• 0.25% NaOCl kills Enterococcus Faecalis in 15 mins in infected dentin blocks• 1% NaOCl kill Candida Albicans in 1 hour• Lower concentrations dissolve mainly necrotic tissue• Higher concentrations allow better tissue dissolution but dissolves both necrotic and vital tissue JoE;32,5;2006/JoE16:580,1990/IEJ 34:429,2001 www.indiandentalacademy.com
  33. 33. Sodium Hypochlorite• To increase the efficacy of NaOCl Lower the pH Increase the temperature Ultrasonic activation of sodium hypochlorite JoE 32;5;2006/OOOOE 94;76:2002 www.indiandentalacademy.com
  34. 34. Chlorhexidine• Broad spectrum Antibiotic• Its use as an endodontic irrigant is based on its substantivity Binding to Hydroxyapatite Long lasting antimicrobial effect• 2% conc used as irrigant• Unable to dissolve necrotic tissue• Less effective of gram negative than on gram positive JoE 32;5:2006 www.indiandentalacademy.com
  35. 35. Chlorhexidine• CHX + Ca(OH)2 show strong antibacterial activity against obligate anaerobes• CHX did not affect the alkalinity of Ca(OH) 2• CHX useful as a final irrigant JoE 32;5:2006 www.indiandentalacademy.com
  36. 36. Iodine Potassium Iodide• IKI kills a wide spectrum of micro organisms• Low toxicity• Acts as an oxidising agent against sulfhydryl groups of bacterial enzymes cleaving disulfide bonds• Combination with CHX kills Ca(OH)2 resistant bacteria more effectively• Possible allergic reaction www.indiandentalacademy.com
  37. 37. M T A D• Mixture of Tetracycline isomer (doxycycline), Acid (citric acid), Detergent (tween 80)• Removes smear layer• More effective in apical third than EDTA + NaOCl• Less destructive to tooth structure than EDTA when used as final irrigant JoE 29;3,2003 www.indiandentalacademy.com
  38. 38. E D T A• Forms stable calcium complex with dentin mud, smear layer and calcific deposits and prevent apical blockage• Negotiating narrow, tortuous canals, calcified canals and to establish patency• Chelators detach biofilms adhering to root canal walls JoE 32;5:2006 www.indiandentalacademy.com
  39. 39. E D T A• Calcium binding releases protons and EDTA loses efficiency in acidic environment• Effervescence or bubbling effect• EDTA reduce available chlorine in NaOCl• So, EDTA should not be mixed with NaOCl• Hydroxyethylidene bisphosphonate (Etidronate) decalcifying agent – Alternative to EDTA as it shows less interference with sodium hypochlorite JoE 32;5:2006 www.indiandentalacademy.com
  40. 40. Other Irrigants used• Calcium Hydroxide (requires prolonged exposure)• Hydrogen Peroxide• Salvizol (N1-decamethylene- bis-4- aminoquinaldinium diacetate)• Advocated use of 0.5% CHX and NaOCl as irrigant can overcome effect of dentin dust on conventional medicaments www.indiandentalacademy.com
  41. 41. Suggested Irrigation Regimen• Hypochlorite solution should be employed throughout instrumentation without altering it with EDTA. Canals should always be filled with Naocl. This will increase the working time of irrigant and cutting efficiency of hand instruments is increased (JOE 1990, 16 418-22) and torsional load on rotary NiTi instruments is improved (IEJ 2005, 38, 223-29)• Between instruments copious irrigation with NaOCl recommended www.indiandentalacademy.com
  42. 42. Suggested Irrigation Regimen [continued]• Once shaping is completed canals can be thoroughly rinse with EDTA for about 1 min. Prolonged exposure with EDTA may weaken the root dentin (JOE 2002, 28, 17) After removing smear layer final rinse with antiseptic solution appears beneficial. The choice of final irrigant depends upon the next treatment step. If intervisit dressing is planned like calcium hydroxide, the final rinse should be Naocl as these chemicals are perfectly complementary (JOE 1998, 24, 326). If the canal walls are perceived to be clean of debris and plan is to fill the root canal, then CHX appears to be most promising agent to be used as a final irrigant. (OOOE 1980, 49, 455) www.indiandentalacademy.com
  43. 43. Alternative concepts• Use of Laser light• Electrochemically activated water• Ozone gas infiltration None of these approaches can match NaOCl• Reducing surface tension of the solutions may increase the penetration into dentinal tubules JoE 32;5:2006 www.indiandentalacademy.com
  44. 44. Indicators• Ruddle Solution/Visualisation Endogram 5% NaOCl Hypaque 17% EDTA• Clinicians use Endograms to visualize microanatomy, verify the shape and monitor remaining root canal thickness• Visualising caries, certain fractures, missed canals and leaking restorations www.indiandentalacademy.com
  45. 45. Ultrasonics• Ultrasonics use sound as an energy source resulting in a three dimensional activation of the file• Alternating attractive and repulsive forces between the plates affect the mechanical vibratory movements, which are then transferred to the instrument• Ultrasonics are available as two designs, either• Piezoelectrical• Magnetostrictive• Endosonic ultrasonic synergistic system is a term coined to describe combined use of ultrasonics in instrumentation and irrigation www.indiandentalacademy.com
  46. 46. Ultrasonics• Druttman and Stock pointed out, "with the ultrasonic method, results depended on irrigation time. “The cleanest canals are achieved by irrigating with ultrasonics and sodium hypochlorite for 3 minutes after the canal has been totally prepared ” (IEJ 1989, 20, 233)• James O. Johnson found that 2% CHX was significantly superior to 5.25% NaOCl with irrigation alone and with final passive ultrasonic activation (JOE 2003, 29, NO 9). www.indiandentalacademy.com
  47. 47. Ultrasonics• Guys Hospital in London pointed out that acoustic streaming "depends on free displacement amplitude of the file" and that the vibrating file is "dampened" in its action by the restraining walls of the canal• The Guys Hospital group found that the smaller files generated greater acoustic streaming and hence much cleaner canals.• At Guys Hospital, another interesting phenomenon was discovered about ultrasonic canal preparation that ultrasonics alone actually increased the viable counts of bacteria in simulated root canals. This was felt to be caused by the lack of cavitation and the dispersal effects of the bacteria by acoustic streaming. On substitution of sodium hypochlorite (2.5%) for water, however, all of the bacteria were killed, proving once again the importance of using an irrigating solution with bactericidal properties JOE 1987, 13, 93/ JOE 1987, 13, 490 www.indiandentalacademy.com
  48. 48. Sonics• Sonic systems uses vibration in audible frequency range for activation of endodontic files• Three sonic files used are Rispisonic, shaper sonic, Trio sonic• When loaded in canal produces longitudinal, up and down motion• Disadvantanges include perforations, transportation www.indiandentalacademy.com
  49. 49. Sonics• Dummer et al the Shaper Sonic files widened the canals more effectively than the Rispi Sonic files, whilst the Trio Sonic files were particularly ineffective• At the University of Minnesota, the ultrasonic units were again tested against the sonic unit. The researchers found the Micro Mega Sonic to be better as they were the fastest in preparation time and caused the "least amount of straightening of the canals.• The sonic technique extruded the least and hand instrumentation the most debris. Ultrasonic was halfway between. IEJ 1989, 22, 211/ JOE 1989, 15, 235 www.indiandentalacademy.com
  50. 50. Position of the apical foramen • Traditional treatment has held that canal preparation and subsequent obturation should terminate at the apical constriction (CDJ)• Some advocated terminating the preparation 0.5 to 1mm short in necrotic cases and 2mm short in irreversible pulpitisIEJ31;3941998/OOOOE89;99,200 www.indiandentalacademy.com 0
  51. 51. Factors related topreparation length • Use of a patency file • Apical width www.indiandentalacademy.com
  52. 52. Patency File• Small K File (#10 size or #15 size) that is passed through the foramen• Suggested for most rotary techniques• Remove accumulated debris and help maintain working length• An in vitro study suggested that risk of innoculation was minimal when canals were filled with NaOCl• Clinical experience suggests this technique JoE 30:92,2004 www.indiandentalacademy.com
  53. 53. Apical Width• Position of apical constriction and diameter is difficult to assess clinically• Some have recommended gauging canal diameters by passing a series of fine files until one fits snugly-likely to result in under estimation of the diameter• Initial canal size determines the desired final apical diameter• Ongoing debate b/w smaller or larger apical preparations www.indiandentalacademy.com
  54. 54. Narrow Apical preparations• Benefits Minimal risk of canal transportation, extrusion of irrigants, or extrusion of filling material Can be combined with tapered preparation to counteract drawbacks• Drawbacks Little removal of infected dentin Apical rinsing effect is questionable Possibly compromised disinfection during inter- appointment medication Not ideal for Lateral condensation www.indiandentalacademy.com
  55. 55. Wide Apical preparations• Benefits• Removal of infected dentin• Access of irrigants and medications in apical third of root canal• Drawbacks• Risk of preparation errors and of extrusion of irrigants and filling material• Not ideal for thermoplastic obturation www.indiandentalacademy.com
  56. 56. • Despite the disagreement it appears that the root canal preparation• should be confined to the canal space• should be sufficiently wide• should incorporate the original root canal cross sections IEJ 36:740,2000 www.indiandentalacademy.com
  57. 57. Canal Preparation Techniques• Various instrumentation techniques developed for Hand and Rotary instruments• Shape of the Access cavity is the pre requisite that must be optimised before any canal preparation www.indiandentalacademy.com
  58. 58. Techniques for Canal Instrumentation• Traditional step back technique• Crown down technique• Apical widening• Balanced force technique• Hybrid technique• 8 Step Method www.indiandentalacademy.com
  59. 59. Step Back/Telescopic technique• Traditional cleaning and shaping strategy• Initial preparation of the apical third of the root canal system followed by various flaring techniques• Apical to coronal preparation• Cuicchi B et al evaluated the curved canal shape using filing and rotational instrumentation technique and stated that step back shaping consistently presented the best taper and stop design IEJ 1990, 23, 139 www.indiandentalacademy.com
  60. 60. Step Back/Telescopic• technique Determine working length• Serially develop an apical stop• Step back preparation by shortening the length of the file and increasing the file sizes• Flaring technique www.indiandentalacademy.com
  61. 61. Crown Down/Step down technique• Most rotary techniques require a crown down approach• Minimizes torsional loads• Reduce risk of instrument fracture• Minimizes the extrusion of necrotic debris periapically• Facilitates better cleaning• Reduces canal curvature• Eases instrument penetration• Increases apical tactile awareness DCNA 48;183,2004 www.indiandentalacademy.com
  62. 62. Crown Down/Step down technique• Step apically by using a series of files while decreasing instrument size or instrument taper• Next smaller file will perform its cutting action deeper leaving the engagement surface of each instrument minimal www.indiandentalacademy.com
  63. 63. Crown Down/Step down technique www.indiandentalacademy.com
  64. 64. Crown Down Pressureless technique• Similar to crown down concept• Rotate straight files 2 times in a clockwise direction sequentially from larger to smaller sizes until a depth of 16mm is reached• Passively use GG or orifice shapers• Establish a provisional WL 3mm short of radiographic apex• Rotate straight files again 2 times from larger to smaller sizes until WL is achieved• Complete crown down preparation with a size 2 times larger than the first file www.indiandentalacademy.com
  65. 65. Balanced Force technique• Roane et al described this technique1. Using a Flex K file/Flex R file, the instrument is rotated clockwise 90o using only light apical pressure2. Instrument is rotated counter clockwise 180- 270 degrees with sufficient apical pressure, dentin shavings are removed with a characteristic clicking sound3. Similar to step 1;advances the instrument apically4. The file is removed with a prolonged clockwise rotation www.indiandentalacademy.com
  66. 66. Hybrid Instrumentation• Ideal preparation for the hybrid concept takes its pattern from the definition by Herbert Schilder and is slightly modified“A three dimensional continuously tapering cone in multiple planes with sufficient apical enlargement preserving foramen position and size” www.indiandentalacademy.com
  67. 67. Hybrid/Double Flared technique• All the basic techniques combined to eliminate the short comings of individual instruments• Use straight files progressively and passively in a larger to smaller sequence• Establish working length• Continue to use larger to smaller files until full WL is reached• Serially prepare apical stop and apical preparation to blend with the coronal step down flare www.indiandentalacademy.com
  68. 68. Benefits of Hybrid technique• Instruments can be used in a manner that promotes their individual strengths• Hand instruments secure a patent glide path• Tapered rotary instruments enlarge coronal canal areas• Less tapered instruments allow additional apical enlargement DCNA48;195,2004 www.indiandentalacademy.com
  69. 69. 8 step technique• Enlargement of coronal third with K/H files/rotary/GG• Working Length determination• Enlargement of apical third with K files upto size #25• Enlargement of middle third to blend coronal flare with apical preparation using reaming motion with K files larger than MAF IEJ 36,49,2003 www.indiandentalacademy.com
  70. 70. Rotary Instrumentation• Light speed instrumentation www.indiandentalacademy.com
  71. 71. Rotary Instrumentation www.indiandentalacademy.com
  72. 72. Rotary Instrumentation• Profile instrumentation www.indiandentalacademy.com
  73. 73. Rotary Instrumentation• Protaper instrumentation www.indiandentalacademy.com
  74. 74. Hybrid Instrumentation www.indiandentalacademy.com
  75. 75. Hybrid Instrumentation www.indiandentalacademy.com
  76. 76. Hybrid Instrumentation www.indiandentalacademy.com
  77. 77. Hybrid Instrumentation www.indiandentalacademy.com DCNA48;197,2004
  78. 78. Non Instrumentation Technique• Lussi and his associates at the University of Bern, Switzerland, introduced devices to cleanse the root canal "without the need of endodontic instrumentation." The first device, reported in 1993, consisted of a "pump" that inserted an irrigant into the canal, creating "bubbles" and cavitation that loosened the debris. This pressure action was followed by a negative pressure (suction) that removed the debris: "The irrigant fluid was injected through the outer tube while the reflux occurred through the inner tube. JOE 1993, 19, 549 www.indiandentalacademy.com
  79. 79. Non Instrumentation• Technique the device More recently, they have improved and reported that the "smaller new machine produced equivalent or better cleanliness results in the root canal system using significantly less irrigant (NaOCl). This cleanses the canal but, of course, does nothing to shape the canal. www.indiandentalacademy.com
  80. 80. Laser assisted Canal preparation• Levy G et al -the Nd:YAG, in combination with hand filing, is able to produce a cleaner root canal with a general absence of smear layer• Takeda et al - root canal walls irradiated by the Erbium:YAG laser were free of debris, the smear layer was removed, and the dentinal tubules were opened• Er:YAG Laser proved more effective than Co2 laser, NaOCl and EDTA irrigation regimens www.indiandentalacademy.com
  81. 81. CONCLUSION• Clinically, it is important to envisage the shaping procedure extending beyond antimicrobial efficacy• Although successful therapy depends on many factors, the most important steps is canal preparation as it determines the subsequent procedures, includes mechanical debridement , creation of space for medicament delivery and optimised canal geometries for adequate obturation. www.indiandentalacademy.com
  82. 82. www.indiandentalacademy.com www.indiandentalacademy.com

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