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Ultrasonics in endodontics

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This presentation describes about the application of utrasonics in endodontics.

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Ultrasonics in endodontics

  1. 1. Presented by : Dr. Arpit Viradiya Guided By : Dr. Sandeep Metgud & Dr. Karthik Reddy ULTRASONICS IN ENDODONTICS
  2. 2. INTRODUCTION • The use of ultrasonics (US) or ultrasonic instrumentation was first introduced to dentistry for cavity preparations using an abrasive slurry. • Although the technique received favorable reviews, it never became popular, because it had to compete with the much more effective and convenient high-speed handpiece.
  3. 3. • However, a different application was introduced in 1955, when Zinner reported on the use of an ultrasonic instrument to remove deposits from the tooth surface. • And the ultrasonic scaler became an established tool in the removal of dental calculus and plaque.
  4. 4. • The concept of using US in endodontics was first introduced by Richman in 1957. • Martin et al. demonstrated the ability of ultrasonically activated K-type files to cut dentin that this application found common use in the preparation of root canals before filling and obturation. • The term endosonics defined as the ultrasonic and synergistic system of root canal instrumentation and disinfection.
  5. 5. • Ultrasound is sound energy with a frequency above the range of human hearing, which is 20 kHz. • The range of frequencies employed in the original ultrasonic units was between 25 and 40 kHz
  6. 6. • There are two basic methods of producing ultrasound The first is magnetostriction, which converts electromagnetic energy into mechanical energy. • The second method is based on the piezoelectric principle, in which a crystal is used that changes dimension when an electrical charge is applied. Deformation of this crystal is converted into mechanical oscillation without producing heat.
  7. 7. • Piezoelectric units have some advantages compared with earlier magnetostrictive units because they offer more cycles per second, 40 versus 24 kHz. The tips of these units work in a linear, back-and-forth, “piston-like” motion, which is ideal for endodontics. • A magnetostrictive unit, on the other hand, creates more of a figure eight (elliptical) motion, which is not ideal for either surgical or nonsurgical endodontic use.
  8. 8. APPLICATIONS OF US IN ENDODONTICS • 1. Access refinement, finding calcified canals, and removal of attached pulp stones • 2. Removal of intracanal obstructions • 3. Increased action of irrigating solutions • 4. Ultrasonic condensation of gutta-percha • 5. Placement of mineral trioxide aggregate (MTA) • 6. Surgical endodontics: Root-end cavity preparation • 7. Root canal preparation
  9. 9. ACCESS REFINEMENT, FINDING CALCIFIED CANALS, AND REMOVAL OF ATTACHED PULP STONES • One of the challenges in endodontics is to locate canals, particularly in cases in which the orifice has become occluded by secondary dentin or calcified dentin. • With every access preparation in a calcified tooth, there is the risk of perforating the root. • The introduction of the microscope, access burs, and US has greatly reduced these risks. • Microscopic visualization and ultrasonic instruments are a safe and effective combination to achieve optimal results.
  10. 10. • In difficult-to-treat teeth such as molars, US has proven to be useful for access preparation, not only for finding canals, but also for reducing the time and the predictability of the treatment • In conventional access procedures, ultrasonic tips are useful for access refinement, location of MB2 canals in upper molars and accessory canals in other teeth, location of calcified canals in any tooth, and removal of attached pulp stones.
  11. 11. • The visual access and superior control that ultrasonic cutting tips provide during access procedures make them a most convenient tool. • When locating the MB2 canals in upper molars, US is an excellent means for the removal of secondary dentin on the mesial wall.
  12. 12. • US works well when breaking through the calcification that covers the canal orifice. • A troughing tip is a good choice for this task (IMG) • bigger tips with a limited diamondcoated extension should be used during the initial phase of removing calcification, interferences, materials, and secondary dentin, as they offer maximum cutting efficiency and enhance control while working in the pulp chamber.
  13. 13. • The subsequent phase of finding canal orifices should be carried out with thinner and longer tips that facilitate working in deeper areas while maintaining clear vision. • Ultrasonic cutting seems to be significantly influenced by the power setting, as larger fragments of dentin are removed at higher power
  14. 14. REMOVAL OF INTRACANAL OBSTRUCTIONS • Clinicians are frequently challenged by endodontically treated teeth that have obstructions such as hard impenetrable pastes, separated instruments, silver points, or posts in their roots. • If endodontic treatment has failed, these obstructions need to be removed to perform nonsurgical retreatment. Many instruments and techniques have been reported earlier.
  15. 15. • Ultrasonic energy has proven effective as an adjunct in the removal of silver points, fractured instruments, and cemented posts. • US has often been advocated for the removal of broken instruments because the ultrasonic tips or endosonic files may be used deep in the root canal system.
  16. 16. SEPARATED INSTRUMENTS • Management of a broken instrument requires an orthograde or a surgical approach. The three orthograde approaches are • (a) attempt to remove the instrument; • (b) attempt to bypass the instrument; • (c) prepare and obturate to the fractured segment. • In most cases, removal of broken instruments from the root canal is difficult and often hopeless.
  17. 17. • To date, no standardized procedure for the safe removal of fractured instruments exists. • Recent advances in endodontics have led to the development of techniques and devices designed specifically for the safe removal of fractured instruments from deep within narrow curved root canals. • US has often been advocated for the removal of broken instruments because the ultrasonic tips or endosonic files may be used deep in the root canal system.
  18. 18. The fragment was removed using ultrasonic tips, and the root canals were successfully negotiated to the apex and cleaned, shaped, and filled The tooth was subsequently restored with two fiber- reinforced posts, one in the palatal and one in the mesiobuccal canal, followed by a dual-cure resin composite core buildup
  19. 19. ROOT CANAL POSTS • Nonsurgical endodontic retreatment of teeth restored with intraradicular posts continues to present a challenge because of the inherent difficulties of removing posts without weakening, perforating, or fracturing the remaining root structure. • US has provided clinicians with a useful adjunct to facilitate post removal with minimal loss of tooth structure and root damage
  20. 20. • Removal is done in a dry field using a continuous stream of air with direct vision of the ultrasonic tip and the coronal portion of the post, alternated by air and water spray to clean the remnants of fibers and dentin. • Using US involves the initial removal of restorative material(s) and luting cement around the post, followed by application of the tip of an ultrasonic instrument to the post (Fig. 5a– g). Ultrasonic energy is transferred through the post and breaks down the cement until the post loosens (107) (Fig. 5h). This method of post removal minimizes loss of tooth structure and decreases the risk of tooth damage
  21. 21. SILVER POINTS AND FRACTURED METALLIC POSTS • Several studies have shown that retrieval of silver cones can be performed with traditional techniques using hand instruments and particular devices and extractors. • The traditional clinical procedure to remove root canal posts or silver points fractured at the orifice consists of exposing the coronal part of the obstacle by cutting an estimated 2.0-mm trough around the obstacle with a fine diamond bur.
  22. 22. • The tip of an ultrasonic unit (Fig. 2h) is then applied to the side of the post fragment at full power with water irrigation. • Ultrasonic vibration is applied for periods of a few seconds followed by drying with compressed air. This should lead to dislodgement of the fragment of the post, which can then be removed with a fine forceps
  23. 23. • An important point to realize when removing silver points is that one is dealing with a very soft material. Any misdirection of a bur can sever the point, complicating the case even further. US has proven to be very helpful in the removal of these points.
  24. 24. INCREASED ACTION OF IRRIGATING SOLUTIONS • The effectiveness of irrigation relies on both the mechanical flushing action and the chemical ability of irrigants to dissolve tissue. • The flushing action from syringe irrigation is relatively weak and dependent not only on the anatomy of the root canal but also on the depth of placement and the diameter of the needle.
  25. 25. • It has been shown that irrigants can only progress 1 mm beyond the tip of the needle (133). An increase in volume does not significantly improve their flushing action and efficacy in removing debris
  26. 26. • The only effective way to clean webs and fins is through movement of the irrigation solution (137), as they cannot be mechanically cleaned • US is a useful adjunct in cleaning these difficult anatomical features. It has been demonstrated that an irrigant in conjunction with ultrasonic vibration, which generates a continuous movement of the irrigant, is directly associated with the effectiveness of the cleaning of the root canal space
  27. 27. • Acoustic streaming, as described by Ahmad et al. (140), has been shown to produce sufficient shear forces to dislodge debris in instrumented canals. • The flushing action of irrigants may be enhanced by using US. • This seems to improve the efficacy of irrigation solutions in removing organic and inorganic debris from root canal walls
  28. 28. • The tissue-dissolving capability of solutions with a good wetting ability may be enhanced by US if the pulp tissue remnants and/or smear layer are wetted completely by the solution and become subject to the ultrasonic agitation.
  29. 29. • Cameron (171) postulated that there is a synergistic effect between sodium hypochlorite (NaOCl) and US. The ability of NaOCl to dissolve collagen is enhanced with heat therefore, the effect of heat on the irrigant produced by ultrasonic action plays an important role. • US as an adjunct with various irrigating solutions contributes to the removal of the smear layer
  30. 30. • Thirty seconds to 1 minute of ultrasonic activation seems to be sufficient to produce clean canals. • For ultrasonic irrigation, the use of medium power was suggested • Ultrasonic vibration can also be effective when touching the shank of a hand file inserted inside the canal.
  31. 31. • To prevent a dampening effect, sonic or ultrasonic files should not contact the canal walls; therefore, the use of smooth files is recommended • In contrast, ultrasonically activated stainless steel files tend to ledge and perforate canal walls because of their sharp cutting surfaces (Fig. 6). • The use of a smooth wire during ultrasonic irrigation in vitro was as effective as a K-file in debris removal
  32. 32. ULTRASONIC CONDENSATION OF GUTTA- PERCHA • Ultrasonically activated spreaders have been used to thermoplasticize gutta-percha in a warm lateral condensation technique. • In some in vitro experiments, this was demonstrated to be superior to conventional lateral condensation with respect to sealing properties and density of gutta-percha (198 –201).
  33. 33. • Ultrasonic spreaders that vibrate linearly and produce heat, thus thermoplasticizing the gutta- percha, achieved a more homogeneous mass with a decrease in number and size of voids and produced a more complete three-dimensional obturation of the root canal system.
  34. 34. • The obturation technique recommended when using the ultrasonic techniques (204, 205) consists of initial placement of a guttapercha cone to the working length followed by cold lateral condensation of two or three accessory cones using a finger spreader. • The ultrasonic spreader is then placed into the center of the gutta-percha mass 1 mm short of the working length and activated at intermediate power to prevent charring of root surfaces and fracture of the ultrasonic spreader.
  35. 35. • After activation, the ultrasonic spreader is removed, and an additional accessory cone is placed, followed by energizing with the activated ultrasonic spreader. This process is repeated until the canal is filled. During each subsequent step, the ultrasonic spreader should be placed slightly more coronally.
  36. 36. PLACEMENT OF MINERAL TRIOXIDE AGGREGATE (MTA) • Witherspoon and Ham (209) described the use of US to aid in the placement of MTA. • The inherent irregularities and divergent nature of some open apices may predispose the material to marginal gaps at the dentin interface. • It was demonstrated that, with the adjunct of US, a significantly better seal with MTA was achieved.
  37. 37. • Placement of MTA with ultrasonic vibration and an endodontic condenser improved the flow, settling, and compaction of MTA. Furthermore, the ultrasonically condensed MTA appeared denser radiographically, with fewer voids
  38. 38. • The recommended placement method consists of selecting a condenser tip, then picking up and placing the MTA with the ultrasonic tip, followed by activating the tip and slowly moving the MTA material down using a 1- to 2-mm vertical packing motion. • Direct ultrasonic energy will vibrate and generate a wavelike motion, which facilitates moving and adapting the cement to the canal walls.
  39. 39. ROOT-END CAVITY PREPARATION • As the prognosis of endodontic surgery is highly dependent on good obturation and sealing of the root canal, an optimal cavity preparation is an essential prerequisite for an adequate root-end filling after apicoectomy. • Root-end cavities have traditionally been prepared by means of small round or inverted cone burs in a microhandpiece.
  40. 40. • Conventional root-end cavity preparation using rotary burs in a microhandpiece is faced with several problems, such as a cavity preparation not being parallel to the canal, difficult access to the root end, and risk of lingual perforation of the root. • Since sonically or ultrasonically driven microsurgical retrotips became commercially available in the early 1990s, this new technique of retrograde root canal instrumentation has been established as an essential adjunct in periradicular surgery.
  41. 41. • The development of ultrasonic and sonic retrotips has revolutionized rootend therapy, improving the surgical procedure with better access to the root end, resulting in better canal preparation. • Ultrasonic retrotips come in a variety of shapes and angles, thus improving some steps during the surgical procedures
  42. 42. • At first glance, the most relevant clinical advantages are the enhanced access to root ends in a limited working space. This leads to a smaller osteotomy for surgical access because of the advantage of using various angulations and the small size of the retrotips. • advantages of this technique includes deeper and more conservative cavities that follow the original path of the root canal more closely. • A better-centered root-end preparation also lessens the risk of lateral perforation.
  43. 43. • Furthermore, the geometry of the retrotip design does not require a beveled root-end resection for surgical access, thus decreasing the number of exposed dentinal tubules and minimizing apical leakage.
  44. 44. ROOT CANAL PREPARATION • In 1980, Martin et al. demonstrated the ability of ultrasonically activated K-type files to cut dentin. • Several studies have shown that ultrasonically or sonically prepared teeth have significantly cleaner canals than teeth prepared by hand instruments.
  45. 45. • Numerous studies have analyzed the different characteristics of ultrasonically activated files, such as cutting efficiency, effect on bacteria characteristics of root canal preparation, mechanical and technical features of files and handpieces, and clinical implications. • The results of the above studies can be summarized as being contradictory. • They failed to demonstrate the superiority of US or sonics as a primary instrumentation technique
  46. 46. CONCLUSIONS • It can be concluded from this review of the literature that US offers many applications and advantages in clinical endodontics. • Improved visualization combined with a more conservative approach when selectively removing tooth structure, particularly in difficult situations in which a specific angulation or tip design permits access to restricted work areas, offers opportunities that are not possible with conventional treatment.
  47. 47. • As a result, access refinement, location of calcified canals, and removal of separated instruments or posts have generated more predictable results. • Finally, integration of new technologies such as US, leading to improved techniques and use of materials, has changed the way endodontics is being practiced today.
  48. 48. THANK YOU

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