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Determination of root canal working length /certified fixed orthodontic courses by Indian dental academy
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Determination of root canal working length /certified fixed orthodontic courses by Indian dental academy



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Determination of root canal working length /certified fixed orthodontic courses by Indian dental academy Determination of root canal working length /certified fixed orthodontic courses by Indian dental academy Presentation Transcript

  • DETERMINATION OF WORKING LENGTH INDIAN DENTAL ACADEMY Leader in Continuing Dental Education www.indiandentalacademy.co
  • INTRODUCTIONBASIS FOR SUCCESSFUL ENDODONTICSTHE HISTORY: As the awareness among dentists increased that natural teeth function more efficiently than artificial ones, it became prudent to save the pulpally involved teeth. William hunter , an English physician in 1910 at Mc gill university addressed on the role of sepsis and antisepsis in which he criticized prosthetics and endodontics in particular by asserting that gold fillings, caps , bridges,and dentures were islets of frank infection and these were responsible for spread of infection. www.indiandentalacademy.co
  • • Rhein adopted X rays in dentistry for endodontic use to determine canal length and degree of filling.• Coolidge, Prinz , Sharp, Blayney, Appleton and others launched a counter attack by demonstrating successful cases of endodontics on sound biologic principles.• By 1930s corner had been turned and treatment of pulpless teeth became integral part of dentistry. www.indiandentalacademy.co
  • OBJECTIVES OF ENDODONTIC THERAPY The objective of endodontic therapy is restoration of the treated tooth to its proper form and function in the masticatory apparatus in a healthy state.Basic phases of therapy: There are three basic phases of endodontic therapy1. Diagnostic phase2. Preparatory phase3. Filling or obliteration of canal. Endodontic therapy may be thought as a tripod with perfectly treated teeth on a pedestal and every leg representing a basic phase. If any leg is faulty entire system may fail. www.indiandentalacademy.co
  • Importance of debridement Endodontic therapy is essentially adebridement procedure that requires removal ofirritants from canal and periradicular tissues ifsuccess is to be gained. As the case demands debridement may becarried out by instrumentation irrigation,placement of intracanal medicament orelectrosurgery. www.indiandentalacademy.co
  • One of the most important steps in canal preparationis determination of working length, Significance of this procedure are; 1. Calculation determines how far into the canal instruments are placed and worked, thus how deeply into the tissues, debris, metabolites,end products and other unwanted items are removed. 2. It will limit the depth to which canal instrument may be placed. 3. It will affect degree of pain and discomfort that patient will feel following appointment.4. If calculated correctly it will play an important role in determining success of treatment. www.indiandentalacademy.co
  • HISTORICAL PERSPECTIVE IN DETERMINATION OF WORKING LENGTH In the early days of endodontic treatmentradiographs were not applied to dentistry yet andworking length was calculated to the site wherepatient experienced feeling for an instrumentplaced into the canal. Obviously errors occurred, sometimes tissueswere left unextirpated resulting in short fillingsand sometimes fillings were too long. www.indiandentalacademy.co
  • DETERMINATION OF WORKING LENGTH The determination of an accurate working length isone of the most critical steps of endodontic therapy. The endodontic Glossary as “the distance from a coronalreference point to the point at which canal preparationand obturation should terminate,” The anatomic apex is the tip or the end of the rootdetermined morphologically, whereas the radiographicapex is the tip or end of the root determined radiographically. Root morphology and radiographic distortion may cause the location of theradiographic apex to vary from the anatomic apex. The apical foramen is the main apical opening of theroot canal. It is frequently eccentrically located awayfrom the anatomic or radiographic apex.Kuttler’s investigation showed that this deviation occurred in 68to 80% of teeth in his study. An accessory foramen is an orifice on the surface of the root communicating with a lateral or accessory canal. They may exist as asingle foramen or as multiple foramina. www.indiandentalacademy.co
  • Anatomic considerations• The apical constriction (minor apical diameter) is the apical portion of the root canal having the narrowest diameter.• This position may vary but is usually 0.5 to 1.0 mm short of the center of the apical foramen.• The minor diameter (a) widens apically to the foramen major diameter (b) and assumes a funnel shape. The apical third is the most studied region of the root canal.• The cementodentinal junction is the region where the dentin and cementum are united, the point at which the cemental surface terminates at or near the apex of a tooth.• It must be pointed out, however, that the cementodentinal junction is a histologic landmark that cannot be located clinically or radiographically.• Langeland reported that the cementodentinal junction does not always coincide with the apical constriction. The location of the cementinodentinal junction also ranges from 0.5 to 3.0 mm short of the anatomic apex.• Therefore, it is generally accepted that the apical constriction is most frequently located 0.5 to 1.0 mm www.indiandentalacademy.co short of the radiographic apex, but with variations.
  • Clinical Considerations Before determining a definitive working length, the coronal access to the pulp chamber must provide a straight line pathway into the canal orifice. Modifications in access preparation may be required to permit the instrumentto penetrate, unimpeded, to the apical constriction.A small stainless steel K file facilitates the process and the exploration of the canal. Once the apical restriction is established, it is extremely important tomonitor the working length periodically since the working length may change as a curved canal is straightened (“a straight line is the shortest distance between two points”). The loss of working length may also be related to1. The accumulation of dentinal and pulpal debris in the apical 2 to 3 mm of the canal2. Failing to maintain foramen patency,3. Skipping instrument sizes, or4. Failing to irrigate the apical one third adequately.5. Ledge formation or to6. Instrument separation7. Blockage of the canal. There has been debate as to the optimal length of canal preparation and the optimal level of canal obturation. Most dentists agree that the desired end point is the apical constriction, which is not only the narrowest part of the canal but a morphologic landmark that can help to improve the apical seal when the canal is obturated. www.indiandentalacademy.co
  • • The measurement should be made from a secure reference point on the crown, in close proximity to the straight- line path of the instrument, a point that can be identified and monitored accurately.• Stop Attachments. A variety of stop attachments are available. Among the least expensive and simplest to use are silicone rubber stops. Several brands of instruments are now supplied with the stop attachments already in place on the shaft. Special tear-shaped or marked rubber stops can be positioned to align with the direction of the curve placed in www.indiandentalacademy.co
  • Disadvantages of Using Rubber• Time consuming Stops.• May move up or down the shaft• So the clinician should develop a mental image of the position of the rubber stop on the instrument shaft in relation to the base of the handle. Any movement from that position should be immediately detected and corrected.• One should also develop a habit of looking directly at the rubber stop where it meets the reference point on the tooth. www.indiandentalacademy.co• It is also essential to record
  • METHODS OF DETERMINING WORKING LENGTH• Ideal Method• The requirements of an ideal method for determining working length include• rapid location of the apical constriction in all pulpal conditions and all canal contents• easy measurement• rapid periodic monitoring and confirmation• patient and clinician comfort• minimal radiation• ease of use in special patients such as those with severe gag reflex, reduced mouth opening, pregnancy etc; and cost www.indiandentalacademy.co effectiveness.
  • Determination of Working Length by Radiographic Method The following items are essential to perform this procedure:• Good, undistorted, preoperative radiographs showing the total length and all roots of the involved tooth.• Adequate coronal access to all canals.• An endodontic millimeter ruler.• Working knowledge of the average length of all of the teeth.• A definite, repeatable plane of reference to an anatomic landmark on the tooth, a fact that should be noted on the patient’s record.• It is imperative that teeth with fractured cusps or cusps severely weakened by caries or restoration be reduced to a flattened surface, supported by dentin.• Failure to do so may www.indiandentalacademy.co result in cusps or weak enamel walls being fractured
  • Ingle’s Method• Measure the tooth on the preoperative radiograph.• Subtract at least 1.0 mm “safety allowance” for possible image distortion or magnification.• Set the endodontic ruler at this tentative working length and adjust the stop on the instrument at that level.• Place the instrument in the canal until the stop is at the plane of reference unless pain is felt (if anesthesia has not been used), in which case, the instrument is left at that level and the rubber stop readjusted to this new point of reference.• Expose, develop, and clear the radiograph.• From this adjusted length of tooth, subtract a 1.0mm “safety factor” to conform with the www.indiandentalacademy.co apical termination of the root canal at the
  • Wein’s recommendations• If, radiographically, there is no resorption of the root end or bone, shorten the length by the standard 1.0 mm.• If periapical bone resorption is apparent, shorten by 1.5 mm.• root and bone resorption are apparent, shorten by 2.0 mm. The reasoning behind this is• If there is root resorption, the apical constriction is probably destroyed—hence the shorter move back up the canal.• When bone resorption is apparent, there probably is also root resorption, even though it may not be apparent radiographically. www.indiandentalacademy.co
  • • Set the endodontic ruler at this new corrected length and readjust the stop on the exploring instrument.• Because of the possibility of radiographic distortion, sharply curving roots, and operator measuring error, a confirmatory radiograph of the adjusted length is desirable.• When the length of the tooth has been accurately confirmed, reset the endodontic ruler at this measurement.• Record this final working length and the coronal point of reference on the patient’s record.• Once again, it is important to emphasize that the final working length may shorten by as much as 1 mm as a curved canal is straightened out by instrumentation.• It is therefore recommended that www.indiandentalacademy.co the “length of the tooth” in a curved
  • Working Length Estimation by Direct Digital Radiography or Xeroradiography• ADVANTAGES• Rapid imaging• Reduction in radiation www.indiandentalacademy.co
  • Determination of Working Length by Digital Tactile Sense• An experienced clinician may detect an increase in resistance as the file approaches the apical 2 to 3 mm.• This detection is by tactile sense.• It is more accurate than other methods for an experienced clinician.However the drawbacks of this method include• Difficulty in locating the apical constriction in teeth with immature apex.• Difficulty in locating the apical constriction in teeth which have constricted canal throughout the length. www.indiandentalacademy.co
  • Determination of Working Length by Apical Periodontal Sensitivity• Any method of working length determination, based on the patient’s response to pain, does not meet the ideal method of determining working length.• Working length determination should be painless.• Endodontic therapy has gained a notorious reputation for being painful, and it is incumbent on dentists to avoid perpetuating the fear of endodontics by inserting an endodontic instrument and using the patient’s pain reaction to determine working length.• If an instrument is advanced in the canal toward inflamed tissue, the hydrostatic pressure developed inside the canal may cause moderate to severe, instantaneous pain. At the onset of the pain, the instrument tip may still be several millimeters short of the apical constriction.When pain is inflicted in this manner, little useful information is gained by the www.indiandentalacademy.co clinician.
  • Determination of Working Length by Paper Point Measurement• In a root canal with an immature (wide open) apex working length is determined by gently pass the blunt end of a paper point into the canal after profound anesthesia has been achieved.• The moisture or blood on the portion of the paper point that passes beyond the apex may be an estimation of working length or the junction between the root apex and the bone.• In cases in which the apical constriction has been lost owing to resorption or perforation, and in which there is no free bleeding or suppuration into the canal, the moisture or blood on the paper point is an estimate of the amount www.indiandentalacademy.co the preparation is overextended.
  • APEX LOCATORSLocating the Apical Foramen withModern Technology www.indiandentalacademy.co
  • Electronic Apex Locators HISTORY:Suzuki (1942)- Consistent electrical resistance between instrument in a root canal and an electrode on the mucosa. They were also called first generation apex locators. He calculated that resistance offered by human mucosa and periodontal ligament was 6.5 kiloohms.Example : SonoexplorerDisadvantages: Cannot be used if conducting fluid is present. www.indiandentalacademy.co
  • Electronic Apex LocatorsHistory:The Resistance Method (first generation)Sunada (1962)Root Canal Meter (1969) www.indiandentalacademy.co
  • Electronic Apex LocatorsHistory:Impedance of the canal (second generation)Inoue (1971)Examples• Neosono• Pio• Apex finder• Endo analyser www.indiandentalacademy.co
  • Electronic Apex LocatorsHistory:Third generationHigh Frequency Examples:• Endocator• Endex• Apex finder A F A• Mark V plus• Justy two• Root ZX• TRI AUTO ZXable to make correct measurement in the presence www.indiandentalacademy.co of conductive fluids with specially coated file
  • ENDEXwww.indiandentalacademy.co
  • APEX FINDER A F A(All Fluids Allowed) www.indiandentalacademy.co
  • Tri AUTO ZXwww.indiandentalacademy.co
  • The Root ZXwww.indiandentalacademy.co
  • Clinical cases no. 1A forty year old male patient named Prakash Mali presented to department of conservative dentistry and endodontics of G D C & H Mumbai with chief complaint of discoloration of tooth and history of trauma. Patient was diagnosed with chronic apical periodontitis and root canal therapy was advised.Following is a preoperative radiograph showing a working length of 22mm www.indiandentalacademy.co
  • Tentative working length www.indiandentalacademy.co
  • Final working length –21mm www.indiandentalacademy.co
  • Case no. 2A thirty year old male patient named Govind Amte presented to department of conservative dentistry and endodontics of G D C & H Mumbai with chief complaint of discoloration of tooth and history of trauma. Patient was diagnosed with chronic apical periodontitis and root canal therapy was advised.Following is a preoperative radiograph showing a working length of 20mm www.indiandentalacademy.co
  • Tentative working length www.indiandentalacademy.co
  • Final working length-- 19mm www.indiandentalacademy.co
  • Case no.3(SLOB RULE)A forty five year old female patient named Usha Uttekar presented to department of conservative dentistry and endodontics of G D C & H Mumbai with chief complaint of pain in lower right posterior region. Patient was diagnosed with acute exacerbation of chronic apical periodontitis and root canal therapy was advised.Following is a preoperative radiograph showing a working length of 17mm mesially and 18mm distally. www.indiandentalacademy.co
  • RADIOGRAPH WITH HORIZONTAL ANGULATION OF 20DEGREES ON MESIAL SIDE NOTE 4 CANALS IN THE TOOTH Final working length was calculated to mesiobuccal 17mm mesiolingual 17mm distobuccal 18mm distolingual 18mm www.indiandentalacademy.co
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