Rotary ii


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Rotary ii

  1. 1. Foramen Last eliminates constrictions in the coronal region allows greater volume of irrigant penetration cleans coronal 2/3’s of canal b/4 apical 1/3 is entered minimizes transportation, zipping, ledging limitsirritants and toxins pushed through the foramen less the engagement of each file ~ 2-5mm reduces the impact of canal curvature working length less likely to change better tactileminimizes breakage less stress, awareness during apical shaping
  2. 2. Apical Control ZoneThe ‘Apical Control Zone’ is a matrix-like region created inthe apical third of the root canal space. The zonedemonstrates an exaggerated taper from the cliniciandefined apical constriction whether this is spatially a linearor point determination. This enhanced taper in the apicalcontrol zone provides resistance form against thecondensation pressures of obturation and acts to preventthe extrusion of the filling material during obturation.
  3. 3. Apical Control Zone
  4. 4. 0.0 mm 200.25 mm 250.5 mm 300.75 mm 351.0 mm 402.0 mm 423.0 mm 444.0 mm 46 DavidRosenberg
  5. 5. Apical Gauging Avoid apical parallelismObjective - linear or point apical control zone
  6. 6. Distal Root1 mm from Apex Canal not debrided and shaped to the correct diameter Necrotic Tissue
  7. 7. Distal Root 1 mm from Apex Necrotic TissueCanals not debrided and shaped to the correct diameter and Debris
  8. 8. What does the literature say about canal diameters?Median of maxillary canal diameters 1mm from apex  Mx. cent. incisor .34mm  Lateral incisor .45mm  Canine .31mm  Premolar .37mm  MB1, MB2 (molar) .19mm  DB .22mm  Palatal .33mm Wu et al 2000
  9. 9. What does the literature say about canal diameters?Median of mandibular canal diameters 1mm from apex  Md. central incisor .37mm  Lateral incisor .37mm  Canine .31mm  Premolar .35mm  MB (molar) .40mm  ML .38mm  Distal .46mm Wu et al 2000
  10. 10. Radiographic Terminus – NOT!! Radiographic terminus alters throughout life – cellular cementum deposition Apical foramen
  11. 11. Electric Foramenal Locators In 1962 Sunada determined that the must turn unit on before attaching resistance between oral mucosa probe to unit… and periodontal ligament is a “might think in previous tooth” constant value 6.5 ohms (40/μAmp) canals can be wet, but chamber must be dry… no shared fluid between canals instrument must be free in access opening… no contact with metal
  12. 12. Anatomic apex PDL, cementum & bone* EAL = 0.0 Bleeding point
  13. 13. Working Length generic knowledge of root lengths measure radiograph –  advantage of digital images foramenal locators foramenal locators USED REPEATEDLY  USED REPEATEDLY final WL determined after coronal debridement – lengths change with shaping
  14. 14. Guru ConclusionsSeveral trends are increasingly evident: most NiTi techniques are hybrid rotary file protocols most operators create tapered apical preparations, ranging from .06 to .2 or more most use a thermolabile technique most use patency files all the time all use foramenal locators as primary length determinant not all take WL x-rays and some use paper points for length confirmation presence of an ACZ is dependent on operator’s technique