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52 Restorative Techniques in Paediatric Dentistry
https://t.me/med1917
FIGURE 4.23 Ferric sulphate is available commercially as Astringedent (15.5%), from Ultradent, USA. It is usually
applied using applicator tips or cotton pledgets.
FIGURE 4.24 Typical bleeding after the removal of the roof of the pulp chamber during the pulpotomy procedure (a).
After 1 minute application of 15.5% ferric sulphate, showing complete haemostasis (b). Bleeding should have initially
been controlled via the use of a moist cotton pledget to assess the inammatory status of the radicular pulp before using
ferric sulphate as a pulpotomy medicament.
FIGURE 4.25 A, B Large occlusal caries in 84, with history of reversible pulpitis, and radiograph showing close
proximity of the cavity to the distal pulp horn.
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FIGURE 4.25 C Removal of caries reveals involvement of the pulp.
FIGURE 4.25 D Haemostasis was initially achieved following the application of a moist cotton pledget, indicating
healthy radicular pulp tissues. The application of 15.5% ferric sulphate for 1 minute could be used to maintain haemostasis while MTA is applied.
FIGURE 4.25 E MTA placed to cover the whole oor of the pulp chamber. Acotton pledget is used to apply gentle
pressure on the MTA after placement to ensure excellent contact with radicular pulp.
FIGURE 4.25 F Glass ionomer placed over the MTA and allowed to set before preparing the tooth for a preformed
metal crown.
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FIGURE 4.25 G Preformed metal crown placed on 84.
FIGURE 4.26 Aseries of follow-up radiographs after a pulpotomy was carried out on 75: (a) pre-operative; (b) imme-
diately post-operative; (c) 3 months; (d) 12 months. There has been no deterioration of the bone in the bifurcation region,
an indication of success.
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Rationale for Discontinuing Use of Formocresol
Since the 1950s, much work has been done to evaluate the effect of formocresol on pulp tissue, including histological, biochemical, and histochemical enzymatic studies. Essentially, formocresol acts
through the aldehyde group of formaldehyde, forming bonds with the side groups of the amino acids
of both the bacterial proteins and those of the remaining pulp tissue. It is therefore both a bactericidal
and devitalizing agent. It kills off and converts bacteria and pulp tissue into inert tissue.
It has also been shown that formocresol inactivates the oxidative enzymes in the pulp tissue adjacent
to the amputation site. It may also have some effect on hyaluronidase action. Therefore, the proteinbinding properties and the inhibition of the enzymes can break the pulp tissue down and result in
‘xation’ of the pulp tissue by formocresol and render it inert and resistant to enzymatic breakdown.
There is no doubt that excellent clinical outcomes have been reported with the use of formocresol
over decades. However, one of the main constituents of formocresol, formaldehyde, has been associated with risk of naso-pharyngeal carcinoma. Also, the rationale for a pulpotomy is the removal of the
pulp that is deemed to be irreversibly inamed and leaving behind uninamed pulp tissue. There is no
reason that a medicament that is essentially a ‘tissue xative’ should be applied to uninamed, healthy
pulp tissue. If the purpose of application is to achieve haemostasis, then there is no better haemostatic
agent than ferric sulphate, which is also readily available in most dental practices.
Equivalent success rates have been reported for formocresol and ferric sulphate in randomized controlled trials. In the recently published guidelines of the European Academy of Paediatric Dentistry,
which was based on an exhaustive systematic review and meta-analysis, the only material which was
found to have no favourable outcomes when used as a pulpotomy medicament was calcium hydroxide.
Based on the preceding rationale, evidence in the literature, and guidelines published by learned
societies, the authors wish to recommend that clinicians consider abandoning the use of formocresol
in favour of ferric sulphate and the newer biocompatible materials. However, it is important to emphasize that the success or failure of pulpotomy depends wholly on the accurate diagnosis of the state of
pulp inammation and not so much on the medicaments used on the pulp.
The Pulpectomy Technique
As discussed in the preceding section, irreversible changes may occur very early in the dental pulp
of the primary teeth. These irreversible changes to the primary pulp may manifest clinically as spontaneous or lingering tooth pain, traditionally diagnosed as ‘irreversible pulpitis’. In many instances,
caries-induced inammation often extends to the radicular pulp without any clinical symptoms of
irreversible pulpitis and only becomes evident from the uncontrollable haemorrhage that occurs after
deroong the pulp chamber during a pulpotomy procedure. Worse still, the pulp may be non-vital or
necrotic, and an abscess may develop with or without acute cellulitis, which is a distressing complication. In these clinical situations, practitioners often extract the primary tooth or, at best, perform a
non-vital pulpotomy. The success rate of the latter procedure is poor and, in the authors’ opinion, is
obsolete and should not be carried out.
Primary teeth diagnosed with irreversible pulpitis or necrotic pulp can be more optimally
treated with two non-vital pulp procedures: (1) conventional pulpectomy and (2) lesion sterilization tissue repair (LSTR). The pulpectomy procedure has been described in the paediatric
dental literature for over four decades and is the technique of choice for primary teeth diagnosed
with irreversibly inflamed or necrotic pulps. LSTR is a relatively more recent technique and is
suggested as an alternative to extracting primary teeth with extensive periradicular pathosis or
internal root resorption.
The aim of this section is to detail the rationale, indications/contraindications, treatment considerations, and a step-by-step clinical guide for carrying out the pulpectomy procedure in primary teeth.
Abrief description of the LSTR technique and its indications is also presented in this section.
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Rationale for Pulpectomy
The rationale for this technique is to remove the irreversibly inamed or necrotic radicular pulp,
gently clean the root canal system, and ll the root canals with a suitable resorbable material. The
pulpectomy procedure aims to maintain the primary tooth in a non-infected state until the time for
its normal exfoliation.
Indications for Pulpectomy
1. Primary tooth with clinical symptoms typical of irreversible pulpitis, i.e., spontaneous pain
or pain that lingers for several minutes/hours after hot or cold stimuli.
2. Primary tooth undergoing pulpotomy that shows extensive bleeding and failure to achieve
haemostasis after the coronal pulp amputation (Figure4.27).
3. Primary tooth undergoing pulpotomy but on deroong reveals a dry pulp chamber (i.e. no
bleeding) or yellowish necrotic areas within the exposed pulp (Figure4.28).
4. The presence of radiographic periapical or furcation radiolucency is another indication of
pulpal necrosis.
5. Non-vital primary tooth with associated infection. An infected primary tooth may manifest
clinically with intra-oral swelling, chronic draining sinus, or as an acute abscess with or
without associated cellulitis (Figure4.30).
FIGURE 4.27 After removal of the coronal pulp, haemorrhage from the radicular pulp should be pale, red, and easy
to control. Persistent bleeding, beyond the recommended time for the haemostatic medicament, implies irreversible
inammation of the radicular pulp and is an indication for pulpectomy.
FIGURE 4.28 Deroong of the 85 has shown necrotic pulp tissue. In such cases, pulpectomy should be considered.
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FIGURE 4.29 Infection in primary teeth usually manifests in the bi/trifurcation region (a), as opposed to the periapi-
cal pathology usually seen in permanent molars. This is because many ne channels of communication exist between
the pulp chamber and the bone in the furcation area. (b) illustrates this point in an extracted primary molar. Note granulation tissue from (arrow) the abscess in the bifurcation.
FIGURE 4.30 The presence of a chronic draining sinus (a) or an acute abscess with or without an associated cellulitis
(b) is also an indication for pulpectomy.
Contraindications for Pulpectomy
1. The medical contraindications for a pulpectomy are the same as those for a pulpotomy (see
preceding section).
2. Primary tooth with a non-restorable crown (Figure4.31).
3. Primary tooth with advanced pathological root resorption (Figure4.32a), internal/external
root resorption, or if the physiological root resorption is more than one-third the root length
(Figure4.32b).
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FIGURE 4.31 Alarge lesion in 65. After removal of all caries, there will not be enough tooth structure left to support
a preformed metal crown restoration, which would be required after a pulpectomy.
FIGURE 4.32 (a) Periapical radiograph showing pathological root resor ption due to a chronic abscess in 74. Extraction
of this tooth rather than restoration is the treatment of choice. (b) Irreversible pulpitis in 75. However, periapical radiograph shows signicant physiological root resorption. Extraction of this tooth rather than pulpectomy is the treatment
of choice.
4. Perforated pulpal oor or the furcal lesion extends to the developing permanent tooth bud
(Figure4.29a).
5. Excessive primary tooth mobility due to inadequate periodontal or bony support.
6. Primary tooth is associated with radicular, dentigerous, or follicular cysts.
Treatment Considerations for Pulpectomy
The inuence of various treatment factors on the overall clinical success of conventional pulpectomy
is briey discussed in what follows, based on evidence from a recent comprehensive systematic review
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and meta-analysis of non-vital pulp therapies in primary teeth (Coll etal. 2020). This will enable
practitioners to make evidence-based clinical decisions when embarking on a pulpectomy procedure
in a primary tooth.
1. One-Visit vs Two-Visit Pulpectomy
Evidence suggests that overall clinical success of pulpectomy is not inuenced by the num-
ber of visits, and clinicians can choose either one-visit or two-visit pulpectomy based on
clinical expertise and patient circumstances. One-visit pulpectomy can be successfully carried out for vital primary teeth diagnosed with irreversible pulpitis, while two-visit pulpectomy may be required for infected primary teeth associated with persistent canal exudate, a
chronic draining sinus, or an acute abscess with or without cellulitis. The technical steps are
the same for both, except that for the two-visit pulpectomy procedure, a root canal dressing
with non-setting calcium hydroxide is placed in the root canals for 7–10 days at the rst visit,
prior to canal obturation at the second visit.
2. Root Length Determination
Working lengths of primary root canals are estimated, keeping them 1–2mm short of the
radiographic apex. Evidence suggests that clinicians may choose any of the root length
determination methods (tactile, radiographs, apex locators) based on their clinical expertise
and individual circumstances with no difference in the overall clinical success whichever
method is chosen.
3. Instrumentation Technique: Manual vs Rotary Instrumentation
Biomechanical preparation plays an important role in cleaning and debriding the primary root
canal system. Manual instrumentation with hand les is the standard method of preparing the
root canals of primary teeth. However, hand preparation techniques are time-consuming and
can lead to iatrogenic errors (e.g., ledging, zipping, canal transportation, apical blockage). To
overcome these drawbacks, Ni-Ti rotary instruments have been introduced even for primary
teeth to improve instrumentation techniques. These include rotary systems that are specically designed for primary teeth (e.g., the Kedo le system). Compared to manual preparation, rotary instrumentation requires less time, removes less dentine, and results in a more
uniform root canal preparation. However, considering that rotary instruments are centred in
the canals, rotatory instruments may potentially leave behind infected pulp tissue, especially
in primary root canals that are ribbon-shaped and have multiple branching accessory canals.
Thus, irrespective of the instrumentation technique used, copious irrigation is key to removing remnant pulp tissues in the primary root canal system.
Evidence suggests that rotary instrumentation requires signicantly shorter time than
manual instrumentation (approximately 2 minutes less) in primary teeth. Complete obturation to the working length (ush ll) also favoured rotary instrumentation, although the
difference between the two instrumentation methods was not signicant. The two instrumentation techniques also had comparable overall clinical success. Considering these ndings and the additional cost, resources, and training required for rotary instrumentation,
clinicians may choose either method of instrumentation for conventional pulpectomy in primary teeth.
4. Irrigation Solutions
While copious irrigation is critical to achieving a clean primary root canal system, the
choice of the irrigating solution (1–5% sodium hypochlorite, chlorhexidine, normal saline)
did not appear to inuence the overall clinical success of pulpectomy. Sodium hypochlorite
had the highest clinical success rates, although not signicantly different from success rates
achieved with chlorhexidine or saline. Therefore, the clinicians may choose any of these
irrigation solutions based on their clinical expertise and individual circumstances.
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5. Smear Layer Removal
The smear layer is an accumulation of dentine and pulp debris formed on canal walls dur-
ing instrumentation, and its removal potentially allows the root canal ller to adapt better.
However, evidence suggests that the clinical success of primary tooth pulpectomy was not
inuenced by whether the smear layer was removed or not.
6. Obturating Materials
The ideal requirements for primary root canal obturating material are presented in Table4.2.
Several materials have been used over the years to obturate the primary root canals during
the pulpectomy procedure. The three most currently used primary root canal obturating
materials are pure slow-setting zinc oxide–eugenol mixed as a slurry; calcium hydroxide–
iodoform paste (Vitapex
TM
); and a powder–liquid system (EndoasTM) consisting of zinc
oxide–calcium hydroxide–iodoform–barium sulphate (powder) and eugenol–parachlorophenol (liquid). Acomparison of these three primary root canal obturating materials is
presented in Table4.3. Other materials that have traditionally been used to obturate primary
TABLE 4.2
Ideal Requirements for Primary Root Canal Obturating Materials
• Resorb at the same rate as the primary root.
• If pressed beyond apex, it should be harmless to the permanent tooth germ and periapical tissues; any
extruded material should resorb easily (Figure4.33).
• Adhere to walls of the canal and should not shrink.
• Easy to insert into the primary root canals and, if needed, be easy to remove.
• Stable disinfecting power.
• Insolubility in tissue uids.
• Radiopaque.
FIGURE 4.33 (a) Zinc oxide–eugenol paste is extruded through the apex of 85. (b) Three months later, there is com-
plete disappearance of the material from the periapical tissues.
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TABLE 4.3
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Commonly Used Primary Root Canal Obturating Materials
Zinc Oxide–Eugenol
Components Powder: Zinc oxide without
the setting accelerator
Liquid: Eugenol
Advantages Anti-inammatory
Anti-analgesic
Insolubility in tissue uids
Radiopaque
Sufcient working time
Cheap and easily available
Disadvan-
tages
Obturating
technique
Resorbs at a slow rate and
might result in a deected
successor
Extruded material or any
remnants can elicit mild
foreign body reaction
Limited anti-bacterial efcacy
Introduced into the root canal
using any one of the
following techniques:
• Handheld or rotary lentulo
spiral
• Handheld plugger with
cotton pellet
• Hedstrom le
Calcium Hydroxide–
Iodoform (VitapexTM)
Pre-mixed paste
consisting of calcium
hydroxide, iodoform,
and silicone oil
Anti-bacterial activity
Any extruded material
resorbs quickly without
eliciting a foreign body
reaction
Easy to introduce and
remove
Radiopaque
Resorbs at a faster rate
than physiologic root
resorption, creating a
‘hollow-tube’ effect
within the canal that
can become a site for
re-infection
Introduced into the root
canal using the
provided syringe and
disposable plastic tips
61Pulp Therapy for Primary Teeth
Zinc Oxide–Eugenol–Calcium
Hydroxide–Iodoform (EndoasTM)
Powder: Zinc oxide, calcium
hydroxide, iodoform, and barium
sulphate
Liquid: Eugenol, parachlorophenol
Rapid resorption of any extruded
material, but no premature
intra-radicular resorption (thus no
‘hollow tube’ effect)
Broad antimicrobial efcacy
Excellent healing capabilities and
bone regeneration characteristics
Material is hydrophilic and can be
used in mildly humid canals
Can cause tooth discolouration
Parachlorophenol component is
cytotoxic and possibly carcinogenic
Introduced into the root canal using
any one of the following
techniques:
• Handheld or rotary lentulo spiral
• Handheld plugger with cotton
pellet
• Hedstrom le
root canals include KRI paste (80% iodoform), Maisto paste (zinc oxide–iodoform–thymol),
and Walkhoff paste (parachlorophenol-camphor-menthol).
Evidence shows that zinc oxide–calcium hydroxide–iodoform and zinc oxide–eugenol
may be better choices as obturating materials for pulpectomy success compared to the iodoform or calcium hydroxide–iodoform pastes. Anetwork analysis ranked zinc oxide–calcium
hydroxide–iodoform material rst, zinc oxide–eugenol second, and iodoform last.
7. Obturating Techniques
Several techniques are available to introduce the obturating material into the primary root
canal system. Among the most commonly used are lentulo spirals (either handheld or rotary),
handheld pluggers, and syringes with different delivery tips. Evidence suggests no statistical difference between these three obturating techniques for both the quality of the root ll
as well as their overall clinical success. However, overlling primary root canals appears
to be related to lower success of pulpectomy. Therefore, clinicians can use any obturating
techniques based on their personal preference but should avoid overlling the primary root
canal.
8. Timing and Type of Post-Pulpectomy Restoration
Preformed metal crowns and composite restorations, when used as post-pulpectomy restora-
tions, had comparable clinical success rates at 12 months. In addition, success rates were
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