This presentation of mine is a brief overview of root canal dressing materials and medicaments for undergraduate and postgraduate students . It also includes active irrigation techniques and their uses etc

2.  Performed simultaneously with the mechanical
debridement
 Functions of irrigants are
› lubrication of the instruments
› flushing out of root canal debris
› chemical degradation of residual pulp tissue
› chemical degradation of the smear layer on the
instrumented surface
› chemical degradation of the microbial biofilm both on
the instrumented and, more importantly, on the
uninstrumented surface
› antibacterial action against the root canal microbiota

3.  Irrigation may be thought of as serving several
functions; each of these functions dominates one of
three distinct phases of irrigation during preparation:
 Phase 1 – during canal negotiation and apical
enlargement – the main requirements are to lubricate
the smooth penetration of the instruments in the tight
channels to the apical terminus and flush out
generated debris
 Phase 2 – during mechanical shaping to a final taper
– the requirement is mainly to flush out generated
debris and to dissolve attached and adherent organic
fragments and to facilitate their flushing out
 Phase 3 – after mechanical shaping is complete – the
main requirement is to deliver the chemically active

5.  Relies on the irrigant having properties that
enable it to be interposed as a thin layer
between instrument and canal wall, facilitating
friction-free movement
 Lubricants also come in the form of gels and
include EDTA-containing pastes, such as
RCPrep and File-eze
 Other agents, such as Glyoxide or Glyde
contain carbamide peroxide (an oxidizing agent)

6.  A reasonably low viscosity of the irrigant should
facilitate flow and flushing of the root-canal
space
 Viscously dominated environment of the root-
canal space due to its small volume renders the
fluid relatively static
 Demands various strategies to help mix and
agitate the solution in the root-canal system

7.  Best solution for degrading pulp tissue is
sodium hypochlorite
 necessary actively to ensure that unreacted
solution reaches the tissue in all parts of the
root-canal system
 Done via the radicular access, both during and
after its preparation
 Diffusion of unreacted molecules, however,
demands very frequent replenishment of the
solution in the radicular access

8.  Concentrations up to 3% are sufficient for
antibacterial effect and tissue-
degradation effect in most cases
 Higher concentrations may be used
intermittently in the case of non-
responding infections or where canal
patency is compromised by compacted
apical debris
 Sodium hypochlorite is a caustic solution
and has the potential to corrode
equipment, bleach clothes and cause a
severe reaction if extruded through the
apical foramen
 A good rubber dam seal must be
ensured

9.  Smear layer is thought to harbor bacteria and
prevent sufficient adaptation of the root filling
material
 Weak organic acids, such as
ethylenediaminetetraacetic acid (EDTA) 17%
may help remove the smear layer if irrigation
with it reaches and reacts with the layer

11.  Microbial biofilm contains an aggregate of
microbes and extracellular polysaccharide
matrix (ECPM), which are both highly adherent
to the canal wall
 Removal is certainly facilitated by organic tissue
solvents, such as sodium hypochlorite and
chelating agents, such as EDTA

12.  Most significant action of the irrigant must be its
ability to kill all elements of the root canal
microbiota
 A number of different antibacterial agents have
been used, which exhibit a range of actions
against the various bacteria

14.  Purpose of the radicular access cavity is to
facilitate delivery of the fluid irrigants that will
help to debride chemically the uninstrumented
surfaces free of the microbial biofilm and other
debris
 In order that access to the entire root-canal
system is maintained during the radicular
access preparation, the dentine filings, chips
and pulp debris generated or displaced must be
flushed out of the system

15.  Initial preflaring of the canal allows the coronal-
most debris to be washed out and creates a
reservoir for easier delivery of the irrigant to the
apical parts of the root-canal system
 Selection of a good delivery system and good
wetting characteristics of the irrigant are crucial
 Delivery of boli of irrigant should be frequent
with agitation, mixing and carriage of the irrigant
apically each time until the apical terminus is
reached with a small file (06 or 08) as tracked
by an EAL

17.  Once the radicular access preparation is complete,
the chemical agents may be delivered with a syringe
and needle into the apical part of the radicular
access; its further penetration to the accessory and
peripheral anatomy may occur either by
› Diffusion along a concentration gradient (inefficient)
› Bulk flow driven by agitation (efficient)
 Clearly, the latter method is preferable but would have
to be actively facilitated as mere needle delivery is
insufficient

18.  Strategies for delivering, agitating, and mixing the
irrigant into the complex anatomy from the prepared
radicular access have increased multifold in recent
years as this need became better understood
 The approaches may be classified into:
› Manual agitation: using hand-files propelled in a push–
pull motion;a gutta-percha cone used in a push–pull
motion
› Sonic agitation: using SonicAir® activated file;
EndoActivator®; Vibringe® (vibrating needle attached
to a syringe)
› Ultrasonic agitation: using Irrisafe file; ProUltra syringe
(vibrating needle); ultrasonically activated normal file
› Pressure/vacuum

19.  The simplest method is to reciprocate a gutta-
percha cone to agitate the irrigant (see Fig.
8.157a)
 With this method, there is an increased risk of
irrigant extrusion through the apical foramina
(see Fig. 8.157b)
 The optimal method for maximizing wall shear
stress and reducing apical extrusion is to use a
gutta-percha cone that fits well apically but is
slightly loose coronally

21.  Activation of irrigant with sonic
or ultrasonic devices involves
the agitation of either a
syringe-delivered bolus of fluid
in the canal or by
simultaneous delivery (via a
custom-reservoir) and
agitation
 Sonic devices available for
irrigant agitation include the
Sonic Air Endo Handpiece
(Micromega 1500, Besancon,
France), which is driven by air
pressure to produce vibration
frequencies of 1500–3000 Hz
and which also drives stainless
steel files to aid simultaneous
canal preparation

22.  The EndoActivator system
(Advanced Endodontics, Santa
Barbara, CA, USA) is electrically
driven and works at the much
lower frequencies of 33, 100, and
167 Hz(designed to use polymer
tips of various sizes (ISO size 15,
25, 35) and tapers (0.02, 0.04) for
agitation of the irrigant to avoid the
potential risks of instrument
separation associated with metal
files, ledge formation and canal
transportation)
 Vibringe consists of a sonically
activated device attached to a
syringe, which is said to create
agitation as the irrigant is
delivered

23.  Much higher frequencies of vibration of the working tip (in the
ultrasonic range, 20–40 kHz) are achieved with either
magnetostrictive or piezoelectric devices
 Magnetostrictive transducers produce an elliptical motion at
the working tip, while piezoelectric transducers produce
longitudinal or transverse linear motions
 In either case, the oscillations are damped by contact of the file
with the canal wall, also reducing the acoustic microstreaming
 Acoustic microstreaming is enhanced by higher power output
and greater flexibility of the file, therefore a small size is better
 To maximize acoustic microstreaming, it is best to use the
ultrasonically energized file without contacting the canal walls;
this is achieved by precurving the instrument and using it after
canal preparation is complete
 That is, the so-called but mislabelled “passive ultrasonic
irrigation”, meaning unconstrained oscillation

25.  EndoVac® is a simple but ingenious device,
which delivers the irrigant into the coronal
chamber but sucks the irrigant down into the
canal through an attachment that passes to the
apical end of the radicular preparation
 There are two sizes of attachments, the smaller
of the two is liable to blockage if the instructions
are not followed
 Another device, the NIT®, also uses
simultaneous delivery and suction but this time
through a single needle allowing separate flows
in the inner and outer casings

27.  Phenol based Agents
 Aldehydes(not in use)
 Halides
 Antibiotics
 Steroids
 Calcium Hydroxide

28.  These, which were once the most commonly
used agents, include phenol, parachlorophenol,
camphorated parachlorophenol, camphorated
monoparachlorophenol, metacresyl acetate,
cresol, creosote, eugenol and thymol
 Gradually over the years more dilute solutions
were adopted and have now largely fallen out of
favour
› Their antibacterial effect is not long lasting
› They are able to diffuse through the temporary
filling material and cause an unpleasant taste in
the mouth
› While some even soften the filling material

29.  Pure phenol was not widely used because of
its toxicity but its chemical modification
monochlorophenol was adopted because of
its lower toxicity & improved bactericidal effect
 A solution of CMCP was made by dissolving
monochlorophenol crystals in camphor
 This agent is also largely out of favour, although still available
as Cresophene (Fig. 8.164a) and presumably used
 It is a clear, slightly yellow solution containing 0.10 g of
dexamethasone base, 5 g of thymol, 30 g of parachlorophenol
and 64.90 g of camphor per 100 g
 It is also available as CMCP (Fig. 8.164b), containing 35%
parachlorophenol and 65% camphor

30.  These include sodium hypochlorite, iodine-potassium-
iodide, and a combination of calcium hydroxide and
iodoform preparations (Vitapex®, Metapex®,
Forendo®)
 Sodium hypochlorite
› fulfils the most important criteria of antibacterial effect
and tissue dissolution, but its efficacy as a medicament
is limited because chemical reaction depletes its effect
rapidly
› In addition, since the canal would need to be flooded,
there may be an interaction with the temporary filling
material

31.  Iodine-potassium iodide
› has low toxicity and good antibacterial effect in vitro
› It is easily made by mixing 4 g of potassium iodide with
2 g of iodine and 94 mL of water
› The canal needs to be flooded but its long-term
effectiveness is not known. It has probably not gained
favour because of its potential for allergic responses
and tooth staining
 Iodoform and calcium hydroxide preparations
(Vitapex®, Diapex® Metapex®, Forendo®, CalPlus®;
Fig. 8.166)
› are recently introduced medicaments with little
information from controlled clinical studies
› They appear to combine the best effects of iodoform
and calcium hydroxide but their support is currently
mainly anecdotal

33.  Topical application of antibiotics (such as bacitracin,
neomycin, polymyxin, chloramphenicol, tyrothricin
and nystatin) in the root canal remained popular with
some clinicians, though with only one study from
Grossman supporting the outcomes
 The substances are not toxic to the periapical tissues,
do not stain teeth and are active in the presence of
organic material. Since no single antibiotic is active
against all the bacteria found in the root canal
system, a combination of antibiotics with different
ranges of activity is used, usually in the form of a
paste
 Objections raised to the use of antibiotic pastes
include the possibility of developing resistant strains,
possible sensitization of the patient & development of

34.  A number of commonly
used systemic
antibiotics were tried in
combination, including
metronidazole,
ciprofloxacin and
minocycline
 The interest was further
raised when they were
adopted for root-canal
dressing in cases of
pulp revascularization

35.  Steroids (prednisolone, triamcinalone,
hydrocortisone, dexamethasone) have been used in
root canals mainly for pain relief and anti-
inflammatory action; there is some clinical evidence
of their anodyne action
 These materials have no other beneficial quality and,
therefore, they may be mixed with other antibacterial
agents, such as calcium hydroxide or antibiotics
 The commercially available paste popularly used in
this manner is Ledermix® , which also contains the
antibiotic tetracycline
 It has been suggested that Ledermix® can stain teeth
when exposed to light, so an alternative product
(Odontopaste®), has used 5% clindamycin

36.  It also contains 0.5% calcium hydroxide with a
caution that it should not be mixed in a 50 : 50 ratio
with calcium hydroxide because it would destroy
the steroid; this is a practice recommended by
some for Ledermix®
 However, mixing these materials reduces the
release of individual components rather than
providing synergism
 The disadvantage of the use of these substances is
the depressive effect they have on the host defence
mechanisms, including inflammation
 Their use may also bring the risk of a bacteraemia

37.  Gained wide popularity and acceptance as an
intracanal medicament as it is effective against most
root-canal bacteria and, additionally, has the ability to
degrade residual organic tissue, making it more
susceptible to dissolution by sodium hypochlorite at a
subsequent appointment
 The duration of the antibacterial effect is dependent
upon the concentration and volume of the material
but it has lasting effect because of its low solubility
 A saturated solution effectively provides a store of
unreacted ions ready to go into solution as the
dissolved ions are removed
 The material is quite irritating if extruded and can
cause localized necrosis that is self-limiting

38.  Extrusion may be accompanied by severe pain
lasting 12 to 24 hours
 It is for this reason that some clinicians prefer to mix it
with a steroid paste
 This ability to cause localized necrosis may help to
form a hard calcific barrier at the junction with the
periapical tissues
 Intracanal medicament for closure of immature apices
, apexogenesis intracanal perforation repairs and
horizontal root fractures before obturation
 These latter actions may also be facilitated by the
property of calcium hydroxide to solubilize the dentine
matrix, releasing sequestered growth factors.

39.  Calcium hydroxide is also readily available,
inexpensive, simple to place and relatively simple to
remove from the root-canal system.
 It does not stain the tooth or affect the temporary
restoration.
 Another benefit attributed to calcium hydroxide is its
ability to dry weeping canals
 The reason for this is unclear but it is probably related
to the antibacterial effect of the material and possibly
the inactivation of toxins
 Calcium hydroxide has been recommended for
treatment of external inflammatory and internal
resorption probably related to its antibacterial
properties

40.  One recently raised concern is that, in common
with sodium hypochlorite, it may affect the
physical properties of dentine adversely,
particularly when used long term. According to
some early studies, it does appear to make
teeth more susceptible to fracture, although the
effect appears to be limited to the surface
 Despite these positive features, recent literature
casts some doubt on the predictability of the
antimicrobial effect, based on the resistance of
Enterococcus faecalis to calcium hydroxide
because of its proton pump mechanism

44.  Many commercially available products e.g.
Multical, Endocal, Hypocal, Rootcal contain
calcium hydroxide together with other ingredients
 The constituents of these commercial products
vary widely: the calcium hydroxide content is
about 34–50%; barium sulphate 5–15%
 The remainder is water and methyl or hydroxyl-
methyl cellulose
 Other antiseptic materials, such as
chlorothymonol may be added
 The disadvantage of commercially available
materials is that the most important ingredient
(calcium hydroxide) is diluted and the pastes may
be more difficult to place with any degree of

45.  Many clinicians prefer to use the pure-
grade calcium hydroxide powder,
which can be mixed in
 a ratio of 7 : 1 with barium sulphate
powder for radiopacity
 The resultant mixture should be stored
in an air-tight bottle
 It may be mixed with water, saline or
local anaesthetic (without
vasoconstrictor) to a paste of the
preferred consistency
 The consistency of the paste can be
changed on demand even within the
canal by simply absorbing water with a
paper point or adding more
 It is therefore very versatile in
placement but it must be remembered
that the agent must be in aqueous
solution to be active
 The powder may also be added as a
thickener to commercial products but
this may adversely affect their
rheological properties

46.  A range of manual and
automated techniques may
be used depending upon the
consistency of the
preparation
 The more fluid, commercially
available pastes may be
applied with files or paper
points but the material is
unlikely to reach all aspects
of the root-canal system
 Some recommend the use of
spiral fillers or an

47.  Calcium hydroxide is relatively easily removed by
washing and irrigating with water or sodium
hypochlorite
 The latter is preferable because it will allow further
dissolution of residual organic debris
 Sometimes, the calcium hydroxide may become
very well compacted in a narrow canal giving the
impression of a blockage
 It is important then to use sufficient water and a
small file to negotiate past it
 An ultrasonically activated file is very effective at
removing calcium hydroxide dressings

48.  The duration of dressing with
calcium hydroxide is dependent
upon the objective of dressing
 If used as a routine antibacterial
dressing, then 7 days are sufficient
 If the objective is to arrest a
weeping canal, then it may be
necessary to dress with a stiffer
paste for a period of at least 14
days
 If it is found that a substantial
amount of the paste has been
resorbed more frequent dressings
with stiffer pastes may be required
 Dressing and irrigation are

49.  The use of calcium hydroxide to induce calcific
repair at the periapex requires longer periods of
dressing
 In the first instance, the dressing is changed at 2–4
weeks to evaluate the degree of loss or
contamination of the calcium hydroxide
 It also allows a further opportunity to irrigate the
canal with sodium hypochlorite and reduce the
bacterial and organic contamination
 The dressing may then be left in place and healing
reassessed at 3–4-monthly intervals
 It has been shown that the frequency of change
may enhance the effectiveness in periapical
resolution but the benefit may be marginal

50.  Criteria for assessment of healing include absence
of intracanal bleeding or exudates, absence of
symptoms, tactile evidence of a barrier and
radiographic evidence of bone resolution adjacent
to the site of calcific repair Incompletely formed
apices can take up to 24 months before a
complete barrier forms, but most are complete by
9 months
 The duration of dressing should be balanced
against the possible damage incurred on the
mechanical properties of dentine.