Ultrasonics have various applications in endodontics. They can be used to refine root canal access and remove calcified deposits, detached pulp stones, and intracanal obstructions like broken instruments. Ultrasonics increase the flushing action of irrigants by generating acoustic streaming that more effectively cleans root canal walls and difficult anatomical features. They also aid in removing posts and silver points with minimal damage to tooth structure. Overall, ultrasonics provide a safe and effective method for various challenges in endodontic treatment.

1. Presented by : Dr. Arpit Viradiya
Guided By : Dr. Sandeep Metgud & Dr. Karthik Reddy
ULTRASONICS IN ENDODONTICS

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. • 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. • 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. • 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. • 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. • 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. 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. 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. • 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. • 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. • 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. • 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. 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. • 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. 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. • 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. 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. 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. • 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

22. 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.

23. • 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

24. • 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.

25. 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.

26. • 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

27. • 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

28. • 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

29. • 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.

30. • 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

31. • 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.

32. • 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

33. 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).

34. • 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.

35. • 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.

36. • 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.

37. 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.

38. • 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

39. • 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.

40. 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.

41. • 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.

42. • 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

43. • 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.

44. • 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.

45. 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.

46. • 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

47. 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.

48. • 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.

49. THANK YOU