Management of the deep carious lesion and the - Ohio State ...

PRACTICE
restorative dentistry
Management of the deep carious lesion
and the vital pulp dentine complex
D. Ricketts, 1
This article describes the relationship between the carious process
and pulp-dentine complex reactions. Where the balance between
the two is in favour of the carious process and where conventional
cavity preparation leads to a direct pulp exposure, the direct pulp
cap technique is described. The success of the technique is
addressed and more importantly an alternative technique for caries
removal, namely stepwise excavation, is described which may lead to
a reduced risk of carious exposure and the need for the direct pulp
cap technique.
Trauma, rapidly progressing caries or
over zealous removal of caries can result
in exposure of the dental pulp. In these situations
a direct pulp capping technique can
be considered in an attempt to preserve the
vitality of the pulp and to stimulate it to produce
a calcific barrier to wall off the exposure.
However, the health of the pulp and its
healing capacity will depend on a number of
factors, including the precipitating event
leading to the exposure.
Following trauma, when a previously
sound, asymptomatic tooth suffers a coronal
fracture involving the pulp, it is widely
accepted that the direct pulp cap is the treatment
of choice, providing the exposure is
small and is treated within 24 hours. 1,2,3 In
this situation the depth of damage to the
pulp tissue is small and the relatively healthy
pulp tissue has considerable reparative
potential, particularly in young teeth with
immature apices and a good blood supply.
However, the caries process can lead to
marked changes within the pulp-dentine
complex, which can vary considerably
depending on the severity of the disease and
the age of the pulp. Where deep dentine
1 Clinical Lecturer, Unit of Comprehensive Restorative
Care, Dundee Dental Hospital, Park Place, Dundee
DD1 4HR
*Correspondence to: David Ricketts
email: d.n.j.ricketts@dundee.ac.uk
REFEREED PAPER
Received 27.02.01; Accepted 16.07.01
© British Dental Journal 2001; 191: 606–610
lesions are concerned it is currently taught
that the peripheral aspect of the cavity
should be rendered completely caries free.
This should be followed by careful excavation
of caries at the base of the cavity, overlying
the pulp until hard, stained dentine is
reached, 4 thus gradually reducing the bacterial
load within the cavity. If at final excavation
the pulp is exposed, the possibility of a
direct pulp cap can be evaluated.
In brief
• The direct pulp cap, whilst
predictable for the traumatically
exposed pulp, has a questionable long
term prognosis where a carious
exposure is concerned
The activity of a deep carious lesion
in dentine can be preferentially
modified, by sealing in the dentine
caries. This allows reparative pulpdentine
complex reactions to take
place
When such lesions are re-entered
after six months or more the risks of
directly exposing the pulp are
reduced
Whilst the literature is replete with studies
on caries and endodontic procedures, relatively
little has been published on the relationship
between caries and the vital
pulp-dentine complex. This article therefore
aims to review the literature on pulpdentine
complex reactions to caries and the
direct pulp capping technique. It will also
aim to address when to place a direct pulp
cap and when to undertake root canal treatment,
what materials to use and the longterm
prognosis of such a procedure. More
importantly, an alternative technique of
caries removal will be discussed which has
been shown to reduce the risk of pulpal
exposure.
Dental caries and the pulp dentine
complex reactions
Dental caries in enamel is a subsurface demineralisation
caused by acids produced by
bacteria in the surface plaque. These acids
diffuse into the tooth structure causing
demineralisation. It is only when the relatively
more mineralised surface zone breaks
down that bacteria colonize the enamel
lesion. At this early stage in the carious
process there is some disagreement as to
when the first pulp-dentine complex reactions
occur. Brännström and Lind (1965) 5
for example, found an increase in chronic
inflammatory cells beneath lesions apparently
confined to enamel, whereas others
report that this only occurs when caries
extends into dentine. 6
At the advancing front of a dentine lesion,
demineralisation also precedes bacterial
invasion. Considerable demineralisation of
dentine occurs prior to bacterial infection 7
and where occlusal lesions are concerned it
is only when the caries extends into the middle
third of dentine and is radiographically
visible that significant infection of the dentine
occurs. 8 Fuzayama investigated the
relationship between dentine softening, discolouration
and bacterial infection and
found that softening preceded discolouration
which in turn preceded bacterial invasion.
9 Thus bacterial acids and products,
such as proteases, diffuse ahead of the bacteria
towards the pulp and a number of factors
influence the rate at which this occurs.
These are namely the concentration of bacterial
by-products, the permeability of the
dentine and the pulpal fluid pressure. 10
The frequency of sugar consumption and
hence acid provoking attacks will affect the
606 BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001

concentration of acid produced in the dental
plaque. This in turn will be moderated to
some extent by saliva or whether the lesion
is open (frank cavitation) or closed, but in
general the more acid produced the greater
the concentration gradient toward the pulp.
The permeability of the dentine, which
resists this inward diffusion of acid, changes
with age. Newly erupted teeth are more permeable
and less mineralised allowing the
rapid diffusion of acids. As such they may be
more susceptible to rapidly progressing
caries. Pulp dentine complex reactions to
this stimulus are aimed at reducing the permeability
of the dentine. The most common
reaction depends upon a vital odontoblast
process and is the deposition of apatite and
whitlockite crystals within the dentinal
tubules leading to dentine tubule sclerosis.
In addition to this, tertiary dentine may also
be laid down by the odontoblast within the
pulp chamber. 10
If the carious process proceeds
unchecked, degenerative changes within the
odontoblasts take place before inflammatory
changes within the pulp occur. 11 This
can lead to complete cell death and replacement
by odontoprogenitor cells from the
subjacent cell rich layer. Differentiation of
these mesenchymal cells into odontoblastlike
cells, can lead to the production of
reparative dentine which, depending on the
severity of the carious lesion, can be irregular
with cellular inclusions or if less aggressive
resemble normal tubular dentine.
Thus there is a fine balance between
the speed of the advancing front of the
dentine lesion and the rate at which
pulp-dentine defenses can be laid down.
These pulp-dentine reactions require a
healthy pulp, however if the carious process
continues unchecked pulpal inflammation
will ensue. In an attempt to evaluate the
relationship between lesion depth and pulpal
inflammation, Reeves and Stanley
(1966) showed that if the advancing front of
the lesion was about 1 mm from the pulp
then no significant disturbance occurred. 12
However, once within 0.5 mm of the pulp
more pathological changes occur, but it was
only when the reactionary dentine itself was
involved that ‘pathosis of real consequence’
was seen. Shovelton also showed that it was
only when the lesion was within
0.25 mm–0.3 mm of the pulp that hyperaemia
and pulpitis occurred. 7
Thus in final excavation of soft pulpal
caries, if direct perforation of the pulp occurs
the relative rate of progression of the lesion
has been faster than the rate of pulp-dentine
reactions. At this stage the pulp is likely to be
inflamed and the decision of whether to place
a direct pulp cap has to be made.
The direct pulp cap.
A direct pulp cap usually involves the placement
of a calcium hydroxide preparation
directly in contact with an exposed pulp.
For a direct pulp cap to be successful a number
of factors have to be met and these are
detailed in Table 1. Lin and Langland (1981)
have shown that teeth with a history of pain
will have an area of necrosis within the pulp
chamber and for many this will extend into
the root canal. 13 Bacterial invasion of pulp
tissue is closely related to this necrosis and as
such these teeth should be endodontically
treated. Teeth exposed during caries
removal will inevitably have some degree of
inflammation although the histological
extent of this cannot be accurately predicted
from a clinical examination. Table 1 provides
sensible but not infallible clinical criteria
for successful direct pulp capping.
It was once thought that only pinpoint
exposures could be pulp capped, however
more recent research would suggest that the
size of exposure has no bearing on clinical
outcome. 14,15,16 Whilst these studies pertain
to traumatically exposed pulps, Mejare
and Cvek (1993) have suggested that deep
carious exposures be opened up so that
1 mm–3 mm of exposed pulp can be
Table 1 Criteria essential for a successful direct pulp cap.
PRACTICE
restorative dentistry
removed. 17 It is important to draw attention
to the fact that this study was on young posterior
teeth and cannot be regarded as a true
direct pulp cap, but rather a partial pulpotomy.
This procedure has a number of
advantages; it reduces the potential for
introduction of dentine chips into the pulp
tissue and it enables good contact between
pulp and capping agent. It has been shown
that dentine chips inadvertently pushed
into the pulp tissue cause severe inflammatory
reaction, which can lead to pulp necrosis.
18,19 It also removes superficially
contaminated pulpal tissue.
It is important to emphasize that whilst
the size of traumatic exposures is not so
important, carious exposures should be
small even if they are opened up further at
operation. It is generally agreed that larger
carious exposures have a poor prognosis due
to a more severely inflammed pulp, risk of
necrosis and bacterial contamination. 20,21,22
The issue of age is also difficult, as there is
no clear cut-off when a direct pulp cap
should no longer be considered. The ageing
process is gradual and with increased age the
pulp tissue becomes more fibrous with a
reduction in pulp volume as a result of physiological
secondary dentine formation and
reactionary dentine due to external stimuli
such as trauma, caries and tooth wear. The
blood supply to the dental pulp is critical to
its health and regenerative capacity, and as
this decreases with age so does its capacity to
respond to a direct pulp cap. Hence rather
than a chronological age as a cut-off, the biological
age of an individual tooth should be
assessed and a previous restorative history
taken into consideration as well as the factors
in Table 1.
History Preoperative assessment Clinical findings.
No recurring or Normal vitality tests. Pink pulp
spontaneous pain. Not tender to percussion. Bleed if touched but not
No swelling. No radiographic evidence excessively.
of periradicular pathology.
Young patient.
Radiographically obvious
pulp chamber and root canal.
BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001 607

PRACTICE
restorative dentistry
Finally the location of the exposure is
important as there should be no pulp tissue
coronal to the exposure. Exposure in a cervical
cavity would lead to reactionary dentine
formation which would restrict the
blood supply to the tissue more coronal to
it, leading to necrosis and failure. These
teeth should therefore be root treated. 23
Calcium hydroxide to date remains the
material of choice for a direct pulp capping
technique in general practice. Its properties
and mode of action have been comprehensively
reviewed previously. 24 However, a relatively
new material, mineral trioxide
aggregate (MTA) has been investigated. 25 It
consists of fine hydrophilic particles, which
when mixed with sterile water results in a
colloidal gel of pH 12.5. This gel solidifies to
a hard structure within approximately 4
hours. Once set, it has a high compressive
strength comparable to IRM or Super EBA.
Both laboratory and clinical studies have
shown this material to be extremely biocompatable
with pulp tissue and to have
good sealing ability against dyes and bacteria.
In a limited study, Pitt-Ford et al.,
showed that direct pulpal exposures treated
with MTA demonstrated more predictable
dentine bridge formation than calcium
hydroxide. 26 It would therefore appear that
this material may be the material of choice
for future pulp caps. However, problems
associated with the material’s difficult handling
properties and prolonged setting time
may preclude its widespread acceptance
despite its superior therapeutic properties.
What is the success rate of the pulp
cap technique?
The success rate of a direct pulp cap is difficult
to establish from the dental literature as
studies fail to clearly identify whether exposures
were due to trauma or caries 27 or
address those resulting from trauma only. 28
Whilst the prognosis of teeth that have
received direct pulp caps as a result of
trauma would appear good 28 those with a
carious exposure fare less well. 29 In a retrospective
study of 123 direct pulp caps on
carious exposures only 37% were clearly
successful after 5 years and after 10 years
80% had failed. 29 Loss of pulp vitality in
these teeth poses a problem as a significant
amount of physiological secondary and
reactionary dentine would have developed
which has the potential to complicate subsequent
root canal treatment. In addition the
root canal system may have become infected
and prognosis for root treatment is less
favorable than if vital pulp tissue were
removed. 30 These results question the success
of the direct pulp cap for carious exposures.
However, a further thorough audit is
required, as only 123 out of a possible 401
teeth with a direct pulp cap were available
for 10 year follow up. 29
The indirect pulp cap.
When caries is thought to extend close to,
or into the pulp, excavation of the pulpal
caries can be stopped at stained but firm
dentine. 31 Calcium hydroxide lining is
applied over the pulpal dentine prior to
placement of the definitive restoration.
This is classically referred to as the indirect
pulp cap. The difficulty with this technique
is knowing how rapid the carious process
has been, how much tertiary dentine has
been formed and knowing exactly when to
stop excavating to avoid pulp exposure.
Using a stepwise approach to caries
removal these parameters can be regulated
with a more predictable outcome.
Stepwise excavation.
It could be argued that in the absence of any
signs and symptoms of pulpitis, and where
the criteria in Table 1 are met, it is over-judicious
removal of caries that leads to a pulpal
exposure. In the majority of cases this can be
avoided if a stepwise approach to caries
removal is adopted. This approach which is
not completely new, 32 has recently been the
subject of renewed interest. Bjørndal et al.
(1997) 33 investigated 31 teeth with gross
caries, which from a clinical and radiographic
examination were thought to have
carious pulpal exposures. In these teeth
caries removal was staged over two separate
appointments 6–12 months apart. At the
first appointment, access to the caries was
gained and the periphery of the cavity made
completely caries free. Soft, wet and pale
coloured dentine was left pulpally, which
has previously been shown to be heavily
infected. 34 The cavity was lined with cal-
cium hydroxide and restored with glass
ionomer and left for 6–12 months.
After this period, cavities were re-entered
and the dentine in all teeth was found to be
darker in colour, harder and drier in consistency.
Microbiological analysis also showed a
significant reduction in cultivable microorganisms
over the period in which the provisional
restorations were in place. These
findings would imply that by removing some
of the carious biomass and sealing the
remaining caries from extrinsic substrate and
oral bacteria, the caries left behind after the
first excavation had become less active. This
allows time for pulp-dentine complex reactions
to take place so that at the second excavation
visit, there is less likelihood of pulpal
exposure. It has also been suggested that by
changing the cavity environment from an
active lesion into the condition of a more
slowly progressing lesion, this will be accompanied
by more regular tubular tertiary dentine
formation. The success of this technique
has been demonstrated in a randomized controlled
study comparing conventional cavity
preparation of such lesions with stepwise
excavation. 35 Using the stepwise excavation
technique significantly fewer teeth had
exposed pulps (17.5%) compared with conventional
caries removal (40%). These
results were echoed in a similar study of deep
carious lesions in primary teeth. 36 In this
study 55 teeth were treated with the stepwise
excavation technique and 55 control teeth
were prepared conventionally. The proportion
of teeth where pulpal exposure occurred
were 15% and 53% respectively. The technique
has also been shown to be successful in
a practice-based study 37 where only 5.3% of
pulps were exposed.
Leaving heavily infected caries, the
dilemma.
The thought of leaving heavily infected carious
dentine for 6–12 months would seem
contrary to teaching in dental schools. It has
been taught that when a restoration is
placed, the presence and severity of pulpal
inflammation is related to the level of bacterial
microleakage around the restoration.
38–41 Thus it would be logical to think
that leaving dentine caries which is heavily
infected would result in similarly severe pul-
608 BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001

pal inflammation. However, teeth that have
been treated with the stepwise excavation
technique do not show any signs or symptoms
of pulpitis. The difference here may lie
in the fact that in the animal studies investigating
the effects of bacterial microleakage,
cavities have been prepared in sound teeth.
The pulp therefore has not had any opportunity
to mount its protective reaction and
the presence of bacteria and their by-products
are in contact with dentine whose
tubules are potentially patent and pulp vulnerable.
To the contrary, there is now a significant
amount of evidence to support the
fact that there are few adverse effects, and
potential benefits when caries is ‘sealed into’
a tooth. These studies can be divided into
those where caries has been ‘sealed in’ with a
simple fissure sealant and those where ultraconservative
caries removal has been
followed by placement of a composite
restoration over active caries.
Fissure sealant studies.
When occlusal caries is visible radiographically,
the lesion extends into the middle third
of dentine 42 and is heavily infected. 8 Studies
have shown that when a fissure sealant is
placed over such lesions there is a significant
reduction in the number of cultivable
microorganisms. 43–48 Such lesions appear to
arrest and no increase in lesion size has been
found radiographically over a period of two
years. 49 In addition no study has reported
symptoms of pulpitis or loss of vitality.
Ultraconservative caries removal.
Perhaps some of the most compelling evidence
is provided by Mertz-Fairhurst et al.,
who in 1998 presented ten year data on 156
ultraconservative, cariostatic sealed restorations.
50 In this study, teeth with clinical and
radiographic evidence of occlusal caries were
minimally prepared by placing a 45°– 60°
bevel in the enamel, surrounding a frankly
cavitated lesion. The bevel was at least 1 mm
wide and placed in sound enamel. No
attempt was made to remove any carious
dentine and the resultant ‘cavities’ were
restored with acid etched composites and
covered with fissure sealant. Although a
number of these teeth have been lost from the
study due to patients failing to return for
recall, 85 have been followed throughout the
ten years. Various progress reports on the
study sample have shown that sealing caries
into the tooth arrests the progress of the
lesion by effectively eliminating the oral
source of substrate to the bacteria within the
lesion. 51-55 Only one restoration appeared to
‘cave-in’, only one succumbed to secondary
caries and 3.5% showed signs of wear. All the
teeth remained symptomless with no signs of
pulpal inflammation or necrosis. 50
Why re-enter?
The success of this technique is dependent
upon the integrity of the restoration and its
seal. Regular recall would be essential. In the
Mertz-Fairhurst et al. study (1998) the regular
recall would identify any lost restoration
at an early stage. However, over the ten year
period between 18% and 45% of patients
failed to attend for annual recall. 50 In the
unlikely event that the restoration should
fail and not be detected, the potentially reactivated
lesion would already be in an
advance stage. Following sealing caries into
the tooth, the carious dentine becomes dry,
harder and darker in colour. 33 As a result
there is shrinkage of the tissue leaving a void
beneath the restoration. These two factors
support the second stage of the stepwise
excavation. However, the work by Mertz-
Fairhurst et al. (1998) 50 would suggest that
the interval between first and second excavation
is not critical and could be left for
considerably longer than 6–12 months.
Thus use of a more conservative technique
for removing caries in a young patient with
very deep lesions could eliminate the need for
the conventional direct pulp cap technique.
In those rare instances when this is still
required, adoption of the stepwise excavation
technique should result in a minimally
inflamed pulp, superior tertiary dentine formation,
less bacterial load and a more predictable
pulp cap. Where this is required the
use of calcium hydroxide, whilst acceptable at
present, may become superceded by a mineral
trioxide aggregate material.
Conclusion
These are exciting times when the conventional
wisdom of caries removal is being
challenged. 56 This together with the evolu-
PRACTICE
restorative dentistry
tion of new dental materials, demand further
research into this subject, particularly
where older more compromised teeth are
concerned.
1 Cox C F, Bergenholtz G, Heys D R, Syed A,
Fitzgerald M, Heys J R. Pulp capping of
dental pulp mechanically exposed to oral
microflora: a 1–2 year observation of wound
healing in monkey. J Oral Pathol 1985; 14:
156–168.
2 Heidi S, Kerekes K. Delayed direct pulp
capping in permanent incisors of monkeys.
Int Endo J 1987; 20: 65–74.
3 Pitt Ford T R, Roberts G J. Immediate and
delayed direct pulp capping with the use of a
new visible light-cured calcium hydroxide
preparation. Oral Surg Oral Med Oral Pathol
1991; 71: 338–342.
4 Kidd E A M, Smith B G N. Pickard’s Manual of
Operative Dentistry. 7th Edition pp 58–59.
Oxford: Oxford University Press; 1996.
5 Brännström M, Lind P O. Pulpal response to
early dental caries. J Dent Res 1965; 44:
1045–1050.
6 Massler M. Pulpal reaction to dentinal caries.
Int Dent J 1967; 17: 441–460.
7 Shovelton D S. A study of deep carious dentine.
Int Dent J 1968; 18: 392–405.
8 Ricketts D N J, Kidd E A M, Beighton D.
Operative and microbiological validation of
visual, radiographic and electronic diagnosis of
occlusal caries in non-cavitated teeth judged to
be in need of operative care. Br Dent J 1995;
179: 214-220.
9 Fuzayama T, Okuse K, Hosoda H. Relationship
between hardness, discoloration and microbial
invasion in carious dentin. J Dent Res 1966; 45:
1033–1046.
10 Kim S, Trowbridge H O. Pulpal reaction to
caries and dental procedures. In Cohen S,
Burns R C, Rudolph P. (eds) Pathways of the
pulp. 7th Ed. pp532–534. Missouri: Mosby Inc;
1998.
11 Trowbridge H O. Pathogenesis of pulpitis
resulting from dental caries. J Endod 1981; 7:
52–60.
12 Reeves R, Stanley H R. The relationship of
bacterial penetration and pulpal pathosis in
carious teeth. Oral Surg 1966; 22: 59–65.
13 Lin L, Langeland K. Light and electron
microscopic study of teeth with carious pulp
exposures. Oral Surg 1981; 51: 292–316.
14 Fuks A B, Cosack A, Klein H, Eidelman E.
Partial pulpotomy as a treatment alternative for
exposed pulps in crown-fractured permanent
incisors. Endodont Dent Traumatol 1987; 3:
100–102.
15 Heide S, Kerekes K. Delayed partial
pulpotomy in permanent incisors of
monkeys. Int Endodont J 1986; 19: 78–89.
16 Klein H, Fuks A, Eidelman E, Chosack A.
Partial pulpotomy following complicated
crown fracture in permanent incisors: a clinical
and radiographic study. J Pedodont 1985; 9:
142–147.
BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001 609

PRACTICE
restorative dentistry
17 Mejare I, Cvek M. Partial pulpotomy in young
permanent teeth with deep carious lesions.
Endodont Dent Traumatol 1993; 9: 238–242.
18 Kalins V, Frisbie H E. Effect of dentine
fragments on the healing of the exposed pulp.
Arch Oral Biol 1960; 2: 96 –103.
19 Mjör I A, Dahl E, Cox C F. Healing of pulp
exposures: an ultrastructural study. J Oral
Pathol Med 1991; 20: 496–501.
20 Dannenberg J L. Pedodontic-endodontics.
Dent Clin North Am 1974; 18: 367–377.
21 McDonald R E, Avery D R. Treatment of deep
caries, vital pulp exposure, and pulpless teeth in
children. In McDonald R E, Avery D R, (eds).
Dentistry for the child and adolescent. 3rd ed. St
Louis: Mosby, 1978.
22 Seltzer S, Bender I B. Pulp capping and
pulpotomy. In Seltzer S, Bender I B (eds). The
dental pulp, biologic considerations in dental
procedures. 2nd ed. Philadelphia: Jb Lippincott,
1975.
23 Stanley H R, Lundy T. Dycal therapy for pulp
exposure. Oral Surg Oral Med Oral Pathol.
1972; 34: 818–827.
24 Forman P C, Barnes I E. A review of calcium
hydroxide. Int Endod J 1990; 23: 283–297.
25 Torabinejad M, Chivian N. Clinical applications
of mineral trioxide aggregate. J Endodon 1999;
25: 197–205.
26 Pitt Ford T R, Torabinejad M, Abedi H R,
Bakland L K, Kariyawasam S P. Using mineral
trioxide aggregate as a pulp-capping material.
J Am Dent Assoc 1996; 127: 1491–1494.
27 Armstrong W P, Hoffman S. Pulp cap study.
Oral Surg Oral Med Oral Pathol. 1965; 15:
1505–1509.
28 Cvek M. A clinical report on partial pulpotomy
and capping with calcium hydroxide in
permanent incisors with complicated crown
fracture. J Endodon 1978; 4: 232-242.
29 Barthel C R, Rosenkranz B, Leuenberg A,
Roulet J-F. Pulp capping of carious exposures:
treatment outcome after 5 and 10 years: a
retrospective study. J Endodon 2000; 26:
525–528.
30 Sjögren U, Hagglund B, Sundqvist G, Wing K.
Factors affecting long term results of
endodontic treatment. J Endodon 1990; 16:
498–504.
31 Kidd E A M, Smith B G N. Pickard’s Manual of
Operative Dentistry. 7th Edition p 59. Oxford:
Oxford University Press; 1996.
32 King J B, Crawford J J, Lindahl R L. Indirect
pulp capping: a bacteriologic study of deep
carious dentine in human teeth. Oral Surg Oral
Med Oral Pathol 1965; 20: 663–671.
33 Bjørndal L, Larsen T, Thylstrup A. A clinical
and microbiological study of deep carious
lesions during stepwise excavation using long
treatment intervals. Caries Res 1997; 31:
411–417.
34 Kidd E A M, Ricketts D N J, Beighton D.
Criteria for caries removal at the enamel
dentine junction: a clinical and microbiological
study. Br Dent J 1996; 180: 287–291.
35 Leksell E, Ridell K, Cvek M, Mejare I. Pulp
exposure after stepwise versus direct complete
excavation of deep carious lesions in young
posterior permanent teeth. Endod Dent
Traumatol 1996; 12: 192–196.
36 Magnusson B O, Sundell S O. Stepwise
excavation of deep carious lesions in primary
molars. J Int Ass Dent Child 1977; 8: 36–40.
37 Bjørndal L, Thylstrup A. A practice-based
study on stepwise excavation of deep carious
lesions in permanent teeth: a 1 year follow-up
study. Community Dent Oral Epidemiol. 1998;
26: 122–128.
38 Bergenholtz G, Cox C F, Loesche W J, Syed S A.
Bacterial leakage around dental restorations: its
effect on the dental pulp. J Oral Pathol 1982; 11:
439–450.
39 Cox C F, Keall C L, Keall H J, Ostro E,
Bergenholtz G. Biocompatibility of surfacesealed
dental materials against exposed pulps.
J Pros Dent 1987; 57: 1–8.
40 Cox C F, Sübay R K, Suzuki S, Suzuki S H, Ostro
E. Biocompatability of various dental materials:
pulp healing with a surface seal. Int J Periodont
Rest Dent 1996; 16: 241–251.
41 Grieve A R, Alani A, Saunders W P. The effects
on the dental pulp of a composite resin and two
dentine bonding agents and associated
bacterial microleakage. Int Endod J 1991; 24:
108–118.
42 Ricketts D N J, Kidd E A M, Smith B G N,
Wilson R F. Clinical and radiographic diagnosis
of occlusal caries: a study in vitro. J Oral Rehabil
1995; 22: 15–20.
43 Handelman S L, Buonocore M G, Heseck D J. A
preliminary report on the effect of fissure
sealant on bacteria in dental caries. J Prosthet
Dent 1972; 27: 390–392.
44 Handelman S L, Buonocore M G, Schoute P C.
Progress report on the effect of a fissure sealant
in dental caries. J Am Dent Assoc 1973; 87:
1189–1191.
45 Handelman S L, Wasburn F, Wopperer P.
Two-year report of sealant effect on bacteria in
dental caries. J Am Dent Assoc 1976; 93:
967–970.
46 Going R E, Loesche W J, Grainger D A, Syed S
A. The viability of micro-organisms in carious
lesions five years after covering with a fissure
sealant. J Am Dent Assoc 1978; 97: 455–462.
47 Jensen O E, Handelman S L. Effect of an
autopolymerising sealant on viability of
microflora in occlusal dental caries. Scand J
Dent Res 1980; 88: 382–388.
48 Mertz-Fairhurst E J, Schuster G S, Fairhurst C
W. Arresting caries by sealants: results of a
clinical study. J Am Dent Assoc 1986; 112:
194–197.
49 Handelman S L, Leverett D H, Espeland M A,
Curzon J A. Clinical radiographic evaluation of
sealed carious and sound tooth surfaces. J Am
Dent Assoc 1986; 113: 751–754.
50 Mertz-Fairhurst E J, Curtis J W, Ergle J W,
Rueggeberg F A, Adair S M. Ultraconservative
and cariostatic sealed restorations: results at
year 10. J Am Dent Assoc 1998; 129: 55–66.
51 Mertz-Fairhurst E J, Call-Smith K M, Schuster
G S, et al. Clinical performance of sealed
composite restorations placed over caries
compared with sealed and unsealed amalgam
restorations. J Am Dent Assoc 1987; 115:
689–694.
52 Mertz-Fairhurst E J, Williams J E, Schustre G S,
et al. Ultraconservative sealed restorations:
three-year results. J Public Health Dent 1991;
51: 239–50.
53 Mertz-Fairhurst E J, Williams J E, Pierce K L,
et al. Sealed restorations: 5 year results. Am J
Dent 1992; 5: 5–10.
54 Mertz-Fairhurst E J, Smith C D, Williams J E,
et al. Cariostatic and ultraconservative sealed
restorations: six year results. Quintessence Int
1992; 23: 827–838.
55 Mertz-Fairhurst E J, Adair S M, Sams D R, et al.
Cariostatic and ultraconservative sealed
restorations: nine-year results among children
and adults. ASDC J Dent Child 1995; 62:
97–106.
56 Kidd E. Caries removal and the pulpo-dentinal
complex. Dent Update 2000; 27; 476–482.
610 BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001

Treatment of deep carious lesions by complete
excavation or partial removal: A critical
review
Van Thompson, Ronald G. Craig, Fredrick A.
Curro, William S. Green and Jonathan A. Ship
J Am Dent Assoc 2008;139;705-712
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CLINICAL PRACTICE CRITICAL REVIEW
Treatment of deep carious lesions by
complete excavation or partial removal
A critical review
Van Thompson, DDS, PhD; Ronald G. Craig, DMD, PhD; Fredrick A. Curro, DMD, PhD;
William S. Green, AB; Jonathan A. Ship, DMD
The treatment of deep carious
lesions approaching
a healthy pulp presents a
significant challenge to
the practitioner. The traditional
management of carious
lesions of any kind dictates the
removal of all infected and affected
dentin to prevent further cariogenic
activity and provide a wellmineralized
base of dentin for restoration.
When the procedure risks
exposing or even breaching the
pulp, however, the course of treatment
becomes less predictable and
may require such measures as indirect
pulp capping (typically using a
protective material such as a calcium
hydroxide–based preparation),
pulpotomy or, in the most extreme
cases, pulpectomy. Choosing among
these options can be daunting for
the dentist—as well as for the
patient, who is advised of the risks
and asked to share in the decision.
To preclude or at least minimize
the potential complications of com-
ABSTRACT
Background. The classical approach to treatment of deep carious
lesions approaching the pulp mandates removing all infected and affected
dentin. Several studies call this approach into question.
Types of Studies Reviewed. A search of five electronic databases
using selected key words to identify studies relating to partial versus complete
removal of carious lesions yielded 1,059 reports, of which the authors
judged 23 to be relevant. Three articles reported the results of randomized
controlled trials.
Results. The results of three randomized controlled trials, one of which
followed up patients for 10 years, provide strong evidence for the advisability
of leaving behind infected dentin, the removal of which would put
the pulp at risk of exposure. Several additional studies have demonstrated
that cariogenic bacteria, once isolated from their source of nutrition by a
restoration of sufficient integrity, either die or remain dormant and thus
pose no risk to the health of the dentition.
Clinical Implications. There is substantial evidence that removing
all vestiges of infected dentin from lesions approaching the pulp is not
required for caries management.
Key Words. Deep caries; deep carious lesions; partial caries removal;
indirect pulp capping; pulpal exposure; stepwise excavation; alternative
restorative treatment.
JADA 2008;139(6):705-712.
Dr. Thompson is a professor and the chair, Department of Biomaterials and Biomimetics, and the director, Protocol Development and Training Core, Practitioners
Engaged In Applied Research and Learning (PEARL) Network, New York University College of Dentistry, New York City.
Dr. Craig is an associate professor, Department of Basic Sciences and Craniofacial Biology and Department of Periodontology and Implant Dentistry, and the
director, Information Dissemination Core, PEARL Network, New York University College of Dentistry. Address reprint requests to Dr. Craig at New York University
College of Dentistry, 345 E. 24th Street/1001S, New York, N.Y. 10010-4086, e-mail “rgc1@nyu.edu”.
Dr. Curro is a clinical professor, Department of Oral and Maxillofacial Pathology, Radiology, and Medicine; the director of pharmacotherapeutic research,
Bluestone Center for Clinical Research; and the director, Recruitment, Retention, and Operations Core, PEARL Network, New York University College of Dentistry,
New York City.
Mr. Green is a scientific writer, PEARL Network, New York University College of Dentistry, New York City.
The late Dr. Ship was a professor, Department of Oral and Maxillofacial Pathology, Radiology and Medicine, New York University College of Dentistry; a professor
of medicine, New York University School of Medicine; and the director, PEARL Network, New York University College of Dentistry, New York City.
JADA, Vol. 139 http://jada.ada.org June 2008 705
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CLINICAL PRACTICE CRITICAL REVIEW
plete excavation of carious dentin close to the
pulp, several authors have investigated and proposed
alternative approaches. One such method,
stepwise (or two-step) excavation, involves the
staged removal of carious tissue. At the patient’s
initial visit, once the clinician has established
that the pulp still is vital, he or she partially
removes necrotic infected dentin, often characterized
as soft and removed easily by using hand
instruments. The clinician then seals the lesion
with a medicament such as calcium hydroxide
and places a temporary restoration. At the second
visit—typically some months after the first and,
in some cases, up to two years later—the clinician
removes all or most of the remaining infected
tissue. The rationale for this approach is that by
this point any remaining bacteria will have died,
residual infected dentin as well as affected dentin
will have remineralized, and reparative dentin
will have been generated, making it easier for the
dentist to remove any remaining carious tissue.
An even more controversial approach is conservative
or ultraconservative removal of carious
tissue, often referred to as “partial caries
removal.” In this method, the practitioner
removes most but not all of the infected dentin,
seals the cavity (with or without indirect pulp
treatment) and proceeds with the restoration. The
tradeoff for avoiding pulpal exposure—leaving
behind a layer of infected dentin—is defended by
citing the substantial evidence (discussed below)
that cariogenic bacteria isolated from their source
of nutrition by a restoration of sufficient integrity
either die or remain quiescent and thus, given
a vital pulp, pose no risk to the health of the
dentition.
Studies comparing either partial caries
removal or stepwise excavation with complete
removal of infected tissue from deep carious
lesions were the subject of a 2006 Cochrane
Review. 1 The Cochrane article, while extremely
valuable, is limited in scope by virtue of being a
meta-analysis focused solely on the results of randomized
controlled trials. In preparing this
review, we sought to cast a wider net by performing
a traditional review, taking into account
observational studies and ancillary investigations
that also might be of interest to the practitioner.
METHODS
We conducted a systematic search of five databases
(MEDLINE, Evidence-Based Medicine
Reviews, the Cochrane Database of Systematic
706 JADA, Vol. 139 http://jada.ada.org June 2008
Copyright © 2008 American Dental Association. All rights reserved.
Reviews, Cochrane Central Register of Controlled
Trials and OVID’s Database of Abstracts of
Reviews of Effects) using the following key words:
deep caries; deep carious lesions; partial caries
removal; indirect pulp capping; pulpal exposure;
stepwise excavation; alternative restorative treatment
(ART). We limited the search to reports
written in English describing studies using
human subjects and published from 1950 through
the first week of November 2007. The literature
search yielded 1,059 articles, of which 23—
including articles relating to restoration
longevity, cariogenic activity and pulp vitality, as
well as those directly addressing partial versus
complete removal of deep carious lesions—
reported results we deemed directly relevant.
RESULTS
We identified 10 articles2-11 accounting for six
studies (four of these articles reported follow-up
results) that directly address the issue of partial
removal of carious tissue from deep lesions
(Table). Three investigations stood out by virtue
of being randomized controlled trials: the 1987
study by Mertz-Fairhurst and colleagues, 2 the
1999 study by Ribeiro and colleagues5 and the
2004 study by Foley and colleagues. 6
Mertz-Fairhurst and colleagues2 used a randomized
split-mouth, four-celled design to compare
sealed composite restorations in teeth
treated via partial caries removal with both
sealed and unsealed amalgam restorations in
teeth from which all carious tissue had been
removed. The study population consisted of 123
patients aged 8 to 52 years who had at least one
pair of frank Class I lesions that, according to the
investigators’ radiographic evaluation, extended
as far as halfway from the dentinoenamel junction
(DEJ) to the pulp. A total of 156 pairs (312
teeth) were included in the study. The investigators
evaluated restorations radiographically as
well as clinically (using a modification of the
Ryge/Snyder criteria12 ) at six months, one year
and two years after treatment. They detected no
significant differences among the three treatments—sealed
conservative, sealed amalgam,
unsealed amalgam—at any period. Mertz-
ABBREVIATION KEY. ART: Alternative restorative
treatment. CFU: Colony-forming unit. DEJ: Dentinoenamel
junction. GIC: Glass ionomer cement.
PEARL: Practitioners Engaged in Applied Research
and Learning.
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TABLE
Summary of studies examining partial caries removal.
Fairhurst’s group followed up these patients
across the next decade, 3,4 finally observing that
“the bonded and sealed composite restorations
placed over the frank cavitated lesions [had]
arrested the clinical progress of these lesions for
10 years.” 4
The randomized controlled trial conducted by
Ribeiro and colleagues, 5 in which they evaluated
the performance of a dentin adhesive system, also
served to test the relative performance of com-
CLINICAL PRACTICE CRITICAL REVIEW
STUDY STUDY DESIGN FOLLOW-UP PERIOD RESULTS
Randomized Controlled Trials
Mertz-Fairhurst and colleagues 2-4 Split-mouth randomized
trial of 156 pairs of teeth,
in subjects aged 8 through
52 years, comparing sealed
resin-based composites
after partial caries removal
versus sealed and unsealed
amalgams after complete
caries removal
Ribeiro and colleagues 5 Randomized controlled
trial of 48 primary molars,
in subjects aged 7 through
11 years, restored with a
resin-bonded composite,
comparing partial versus
complete caries removal
Foley and colleagues 6 Split-mouth randomized
controlled trial of 88 teeth
in 44 subjects aged 3.7
through 9.5 years; teeth
divided into four groups:
complete or partial caries
removal restored with
copper phosphate cement
with or without glass
ionomer cement or
amalgam
Observational Studies
Fairbourn and colleagues 10 Observational study of the
effect on cultivatable flora
after partial caries removal
followed by zinc oxide
eugenol with or without
calcium hydroxide base in
40 permanent teeth
Maltz and colleagues 7,9,
Oliveira and colleagues 8
Observational study of partial
caries removal in 32
subjects aged 12 through
23 years
Marchi and colleagues 11 Observational study of the
effect of calcium hydroxide
and resin-modified glass
ionomer liners on indirect
pulp caps of 27 primary
molars in subjects aged 4
through 9 years
Clinical and radiographic
follow-up at
six months and at one,
two, five and 10 years
Extracted near time of
exfoliation and examined
radiographically
and via electron
microscopy
Restorations assessed
clinically at six-month
intervals for 24
months and radiographically
at 12 and
24 months
At reentry after five
months, the remaining
infected dentin was
removed and cultivated
for microbiological
analysis
Clinical, radiographic
and microbiological
data collected at
reentry at six to seven,
14 to 18, and 36 to 45
months after
treatment
Examined at four
years for clinical or
radiographic evidence
of pulp pathology
Copyright © 2008 American Dental Association. All rights reserved.
No differences noted among
groups at any time of
follow-up
No differences noted
between groups
Use of copper phosphate
cement plus glass ionomer
cement resulted in more
abscess or sinus formation;
use of glass ionomer cement
alone resulted in no differences
between groups
Nine of 20 teeth treated
with calcium hydroxide and
five of 20 teeth treated with
zinc oxide–eugenol were
sterile
Remineralization occurred
and caries was arrested at
each of the three times of
follow-up
88 percent success for calcium
hydroxide and 93 percent
success for resinmodified
glass ionomer
plete and partial caries removal. After etching,
the investigators applied a bonding agent to both
carious and noncarious dentin in 48 primary
molars of 38 children aged 7 to 11 years. In one
group, the clinicians removed carious dentin completely
from the DEJ but only superficially from
the remainder of the cavity; they treated a second
group by completely excavating caries. The investigators
extracted 40 teeth (20 from each group)
at about the time of exfoliation (approximately
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CLINICAL PRACTICE CRITICAL REVIEW
one year after treatment) and subjected the teeth
to radiographic and scanning electron microscopic
analysis. These results, as well as evaluations of
retention rates, marginal integrity and pulpal
symptoms, indicated no significant differences
between the two groups.
A more recent study by Foley and colleagues 6
compared the cariostatic effectiveness of alternative
restorative materials in both partial and complete
removal of carious tissue. The authors used
a split-mouth design in 44 patients aged 3.7 to 9.5
years who had at least one pair of previously
unrestored primary molars that had no pulpal
involvement. They treated one tooth of each pair
by complete caries removal and the other by
incomplete caries removal followed by restoration
using copper phosphate cement, glass ionomer
cement (GIC) or both, or a material “of the operator’s
choice” (such as amalgam). At 24 months
after treatment, teeth that had undergone partial
caries removal followed by restoration with
copper phosphate cement and GIC exhibited
greater abscess or sinus formation than did teeth
that had undergone other treatments. Restorations
placed in teeth treated with GIC alone after
partial caries removal, however, exhibited a durability
and effectiveness comparable with those
placed in teeth that had undergone complete
caries removal.
In an observational study, Maltz and colleagues
7 investigated the effects of partial caries
removal in 32 teeth with deep carious lesions. On
the basis of clinical, radiographic and microbiologic
evidence at reentry six to seven months after
treatment (after which they placed a permanent
restoration), the authors concluded that remineralization
had taken place and that caries had
been arrested. In follow-up studies of the same
patients, the authors reported similar results 14
to 18 months after treatment 8 and 36 to 45
months after treatment. 9
Fairbourn and colleagues 10 reported the effect
of indirect pulp capping, after partial caries
removal, on cultivable aerobic and anaerobic bacteria.
These investigators restored 40 permanent
asymptomatic teeth that had carious occlusal or
interproximal lesions approaching the pulp after
partial excavation of infected dentin in which zinc
oxide–eugenol (Caulk IRM Intermediate Restorative
Material, Dentsply Caulk, Milford, Del.) with
or without a calcium hydroxide base (Dycal,
Dentsply Caulk) was used. After five months,
they isolated the teeth, excavated the remaining
708 JADA, Vol. 139 http://jada.ada.org June 2008
Copyright © 2008 American Dental Association. All rights reserved.
infected dentin and cultivated it to identify bacterial
species. Both groups showed a dramatic
decrease in colony-forming units (CFUs); nine of
20 teeth treated with the calcium hydroxide liner
and five of 20 teeth treated with zinc oxide–
eugenol had become operationally sterile (< 300
CFUs per milligram of dentin). The authors concluded
that reentry to remove residual infected
dentin with either restorative material may be
unnecessary, provided that the restoration maintains
an effective seal.
Marchi and colleagues 11 studied the effectiveness
of two protective liners, calcium hydroxide
and resin-modified glass ionomer, in the indirect
pulp treatment of 27 primary molars. At four
years after treatment, the success rate using the
former was 88.8 percent and using the latter was
93 percent. The investigators defined “success”
essentially as the absence of any “clinical radiographic
signs or symptoms of irreversible pulp
pathologies or necrosis.” The authors concluded
that “indirect pulp capping in primary teeth
arrests the progression of the underlying caries,
regardless of the material used as a liner.” 11
Several studies that did not focus on partial
caries removal nevertheless are relevant to the
treatment of deep carious lesions. There has been
evidence for several decades, for example, that
caries development is arrested in sealed lesions.
Handelman and colleagues 13-17 have published
extensively on this subject. Perhaps most frequently
cited is their 1976 study, 13 in which they
placed sealants on 60 teeth with carious lesions
extending into the dentin; 29 unsealed teeth
served as control specimens. They sampled teeth
for bacterial culture at periods ranging from one
week to two years; at the latter point, they found
a substantial decrease in the number of cultivable
microorganisms in sealed lesions when compared
with the unsealed control teeth. Interestingly,
they found the greatest amount of bacterial
reduction within two weeks after treatment. In a
subsequent study, Handelman’s group, 14
describing a radiographic analysis of teeth
treated similarly to those in the 1976 study,
reported a significant decrease in caries penetration
in teeth in which the sealant remained
intact. Bjorndal and colleagues, 18 performing stepwise
excavation, cultured bacteria from the
dentin of 19 teeth after the initial procedure and
after intervals of six to 12 months; at the latter
point, they observed that CFUs had been reduced
substantially.
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Two randomized controlled trials comparing
stepwise and complete excavation, while only tangentially
relevant to the partial caries removal
technique, nevertheless are important for results
relevant to the risk of pulpal complications after
complete removal of deep caries. Magnusson and
Sundell 19 reported postprocedural pulpal complications
in eight (15 percent) of 55 teeth treated by
stepwise excavation and in 29 (53 percent) of 55
teeth treated by direct excavation. Leksell and
colleagues 20 similarly reported pulpal exposure in
10 (17.5 percent) of 57 teeth treated in stepwise
fashion compared with 28 (40.0 percent) of 70
teeth treated by direct excavation.
A 2002 study comparing the efficacy of two
materials used in conjunction with indirect pulp
capping in 48 primary molars reported a success
rate, as measured by absence of irreversible pulp
pathology, of 96 percent for teeth treated with a
proprietary adhesive resin system at two years
after treatment. 21
Al-Zayer and colleagues 22 retrospectively analyzed
187 primary posterior teeth (132 patients)
treated with indirect pulp capping in which sufficient
carious dentin was left to preclude pulpal
exposure. The authors then followed up patients
clinically and radiographically for periods ranging
from two weeks to 73 months after treatment. Of
the 187 teeth in the study, nine (4.8 percent)
experienced complications, amounting to a 95 percent
success rate.
Kreulen and colleagues, 23 using a split-mouth
model, sampled carious dentin from molars before
restoring the teeth using either a “biologically
active” (that is, antimicrobial) resin-modified glass
ionomer preparation or amalgam. They processed
samples for viable bacteria and evaluated them for
color and consistency. Dentin from the same sites
similarly sampled and evaluated at six months
after treatment in 39 patients from both groups
exhibited a significant decrease in the mean
number of bacteria and a significant “overall
treatment” effect for color and consistency.
In a microbiological study of dentin samples
taken from 40 carious lesions before and after
undergoing ART, Bonecker and colleagues 24 found
significant reductions in the frequency and proportions
of total viable cells as well as of mutans
streptococci (but not lactobacilli) in restorations
sealed with a GIC.
Vij and colleagues 25 conducted a retrospective
analysis of two approaches to treating carious
lesions approaching the pulp in 226 primary
Copyright © 2008 American Dental Association. All rights reserved.
CLINICAL PRACTICE CRITICAL REVIEW
molars (141 patients), including 133 teeth from a
previous study 26 that used similar criteria for the
same treatments. The investigators treated all
teeth in two stages (not to be confused with stepwise
excavation). First, they removed superficial
carious tissue and temporarily filled the cavity
with either zinc oxide–eugenol or GIC. Then, at a
second appointment one to three months later,
they either removed the remaining carious tissue
completely and performed a pulpotomy followed
by treatment with formocreosol or removed all
but the deepest layer of remaining carious dentin
and performed indirect pulp capping by using one
of two GIC preparations. At three years after
treatment, the success rate—as measured by the
absence of swelling, abnormal mobility, pain and
radiographic signs of pathology—was 94 percent
for teeth treated by means of partial caries
removal and indirect pulp capping and 70 percent
for the group treated by means of formocreosol
pulpotomy. While this study cannot serve to measure
the relative merits of partial caries and complete
caries removal per se, it demonstrates the
relative superiority of partial caries removal to a
technique (formocreosol pulpotomy) that some
consider a viable alternative.
DISCUSSION
Is it necessary to remove all carious tissue from
lesions approaching the pulp? Although there is
substantial evidence to the contrary, most practitioners
continue to follow the basic principle
guiding any surgeon: that one must eradicate any
and all affected tissue from the site of an infection.
It is not clear, however, whether this principle
is, or ought to be, followed at all times. In
conventional endodontic therapy, for example,
which has a high rate of clinical success, it is
likely that viable bacteria and necrotic host tissue
typically remain in the root canal system after
instrumentation and obturation. 27
The conventional treatment paradigm has a
long history. G.V. Black, in his classic 1908 text,
asserted that “it is better to expose the pulp of a
tooth than to leave it covered only with softened
dentine.” 28 More recently, the majority of respondents
to a survey on this subject indicated that
they would remove all carious tissue even if the
procedure, in their judgment, would risk pulpal
exposure; only about one in five respondents said
they would choose to proceed with partial caries
removal, and a slightly higher proportion indicated
that they would initiate or refer the patient
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CLINICAL PRACTICE CRITICAL REVIEW
for endodontic treatment. 29 In another recent
survey, conducted in 2006, the majority of
respondents opted for pulpotomy as the treatment
of choice in a similar scenario. 30
Ironically, G.V. Black also stated that it is
imperative that dentists understand the
pathology of the caries process lest they be
reduced to the role of mechanics. 31 It is interesting
to speculate, given our ability to create a
restoration with well-sealed margins and associated
grooves and fissures, what Black would say
about the subject of partial caries removal today.
Several of the studies cited above (such as those
by Handelman and colleagues, 13 Kreulen and colleagues,
23 Maltz and colleagues 7-9 and Bonecker
and colleagues 24 ) have demonstrated that bacterial
counts under sealed restorations become
drastically reduced. In their 2002 study, Maltz
and colleagues, 7 citing significant decreases in
counts of both aerobic and anaerobic viable bacteria
and radiographic evidence of a mineral gain
in affected areas, concluded that “complete
dentinal caries lesion removal is not essential to
the control of caries lesions”—a conclusion that
was repeated in two follow-up studies. 8,9 Kidd, 32
who cited most of these same sources and several
others, including studies of stepwise excavation
and partial caries removal, concluded that “there
is no clear evidence that it is deleterious to leave
infected dentine.”
Some of the best evidence for the rationale
underlying partial caries removal can be found in
studies of a related technique, the stepwise excavation
approach. The literature regarding stepwise
excavation 18-20,33,34 has reported consistently
that residual carious dentin recedes and hardens
under temporary restorations in the interim
between the initial excavation and reentry. But
as Kidd 32 stated, “Why re-enter?” In other words,
if the goal is to avoid pulpal exposure and
residual carious dentin poses no threat to the
dentition, why subject the patient to a second
excavation?
Assuming it is preferable to leave caries in
deep restorations, must the practitioner alter his
or her restorative technique? The previously cited
survey of dentists conducted by the Practitioners
Engaged in Applied Research and Learning
(PEARL), a practice-based research network at
the New York University College of Dentistry
sponsored by the National Institutes of Health, 29
may hold an answer to that. The survey’s
respondents, who represented a wide range of
710 JADA, Vol. 139 http://jada.ada.org June 2008
Copyright © 2008 American Dental Association. All rights reserved.
approaches to restoration, stated that they
expected that roughly the same percentage of
their patients would require endodontic treatment
three to five years after treatment regardless
of whether the respondent favored complete
or partial caries removal in deep lesions and
regardless of the respondent’s restoration technique.
Evidence from the literature also suggests
that a change of approach is unnecessary. Even
before the advent of dentin bonding, the efficacy
of bonding to enamel alone was demonstrated in a
17-year recall study of a large-particle ultraviolet
light–cured resin-based composite in Class I and
Class II restorations. 35 Moreover, Mertz-Fairhurst
and colleagues 4 demonstrated that bonding to
enamel alone (with carious dentin remaining) was
sufficient at 10 years. Dentin bonding adds to our
ability to seal restorations, but its long-term efficacy
is still in question. 36
Partial removal of caries from deep lesions usually
involves complete removal of carious tissue
from cavity walls but limited removal from the
pulpal floor and axial wall, which are sites of
reduced bond strength. Resin-based composite
restoration polymerization shrinkage can result
in retraction of the bonding agent from the pulpal
floor or axial wall of sound dentin. 37,38 The
resulting gap can fill with fluid, and with tooth
deformation, the fluid is forced down open
dentinal tubules, causing postoperative “occlusal
loading sensitivity.” While clinicians may find
pulpal floor gaps more often when deep caries
remains because of composite’s inability to bond
completely to caries-infected and caries-affected
dentin, 39-42 the chance of postoperative hypersensitivity
might be reduced because the pulp is protected
from fluid flow in the tubules by the lowpermeability
zone in deep infected dentin. 43,44 On
the basis of these findings, one might suggest
that infected dentin be removed completely from
preparation walls but selectively from the pulpal
floor or axial wall.
Finally, it is worthwhile to consider the recent
meta-analysis 1 that pooled the results of four of
the randomized controlled trials discussed earlier:
those by the Mertz-Fairhurst, 2 Ribeiro, 5 Magnusson
19 and Leksell 20 research groups. The
review is entitled “Complete or Ultraconservative
Removal of Decayed Tissue in Unfilled Teeth,”
and while one can argue that “ultraconservative”
does not apply to the focus of the studies by Magnusson
and colleagues 19 and Leksell and colleagues
20 (stepwise excavation), the authors nev-
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ertheless came to the conclusion—tempered by
their observation that the number of these trials
is small—that “partial caries removal is …
preferable to complete caries removal in the deep
lesion, in order to reduce the risk of carious exposure
[of the pulp].” 1 Apparently, dentists need
more evidence before they will accept this determination—despite
the fact that (to our knowledge)
no study has been initiated to prove the
desirability of removing all infected dentin. An
observational study under way within the
PEARL practice-based research network will
attempt to fill in some of the gaps in our understanding
of deep caries treatment and may provide
the basis for a clinical trial.
CONCLUSION
On the basis of the studies cited in this review,
one can state that there is substantial evidence
that the removal of all infected dentin in deep
carious lesions is not required for successful
caries treatment—provided that the restoration
can seal the lesion from the oral environment
effectively. However, before this concept is
accepted generally by the dental profession, additional
clinical trials may be needed. ■
Disclosures. None of the authors reported any disclosures.
The authors acknowledge the support of the National Institute of
Dental and Craniofacial Research, National Institutes of Health,
through grant U-01-DE016755-01 awarded to the New York University
College of Dentistry, New York City.
1. Ricketts DN, Kidd EA, Innes N, Clarkson J. Complete or ultraconservative
removal of decayed tissue in unfilled teeth. Cochrane Database
Syst Rev 2006;3:CD003808.
2. Mertz-Fairhurst EJ, Call-Smith KM, Shuster GS, et al. Clinical
performance of sealed composite restorations placed over caries compared
with sealed and unsealed amagam restorations. JADA
1987;115(5):689-694.
3. Mertz-Fairhurst EJ, Richards EE, Williams JE, Smith CD,
Mackert JR Jr, Schuster GS, et al. Sealed restorations: 5-year results.
Am J Dent 1992;5(1):5-10.
4. Mertz-Fairhurst EJ, Curtis JW Jr, Ergle JW, Rueggeberg FA,
Adair SM. Ultraconservative and cariostatic sealed restorations:
results at year 10. JADA 1998;129(1):55-66.
5. Ribeiro CC, Baratieri LN, Perdigao J, Baratieri NM, Ritter AV. A
clinical, radiographic, and scanning electron microscopic evaluation of
adhesive restorations on carious dentin in primary teeth. Quintessence
Int 1999;30(9):591-599.
6. Foley J, Evans D, Blackwell A. Partial caries removal and cariostatic
materials in carious primary molar teeth: a randomised controlled
clinical trial. Br Dent J 2004;197(11):697-701; discussion 689.
7. Maltz M, de Oliveira EF, Fontanella V, Bianchi R. A clinical,
microbiologic, and radiographic study of deep caries lesions after
incomplete caries removal. Quintessence Int 2002;33(2):151-159.
8. Oliveira EF, Carminatti G, Fontanella V, Maltz M. The monitoring
of deep caries lesions after incomplete dentine caries removal: results
after 14-18 months. Clin Oral Investig 2006;10(2):134-139.
9. Maltz M, Oliveira EF, Fontanella V, Carminatti G. Deep caries
lesions after incomplete dentine caries removal: 40-month follow-up
study. Caries Res 2007;41(6):493-496.
10. Fairbourn DR, Charbeneau GT, Loesche WJ. Effect of improved
Dycal and IRM on bacteria in deep carious lesions. JADA
1980;100(4):547-552.
Copyright © 2008 American Dental Association. All rights reserved.
CLINICAL PRACTICE CRITICAL REVIEW
11. Marchi JJ, de Araujo FB, Froner AM, Straffon LH, Nor JE. Indirect
pulp capping in the primary dentition: a 4 year follow-up study. J
Clin Pediatr Dent 2006;31(2):68-71.
12. Ryge G, Snyder M. Evaluating the clinical quality of restorations.
JADA 1973;87(2):369-377.
13. Handelman SL, Washburn F, Wopperer P. Two-year report of
sealant effect on bacteria in dental caries. JADA 1976;93(5):967-970.
14. Handelman SL, Leverett DH, Solomon ES, Brenner CM. Use of
adhesive sealants over occlusal carious lesions: radiographic evaluation.
Community Dent Oral Epidemiol 1981;9(6):256-259.
15. Leverett DH, Handelman SL, Brenner CM, Iker HP. Use of
sealants in the prevention and early treatment of carious lesions: cost
analysis. JADA 1983;106(1):39-42.
16. Handelman SL, Leverett DH, Espeland M, Curzon J. Retention of
sealants over carious and sound tooth surfaces. Community Dent Oral
Epidemiol 1987;15(1):1-5.
17. Handelman S. Therapeutic use of sealants for incipient or early
carious lesions in children and young adults. Proc Finn Dent Soc
1991;87(4):463-475.
18. Bjorndal L, Larsen T, Thylstrup A. A clinical and microbiological
study of deep carious lesions during stepwise excavation using long
treatment intervals. Caries Res 1997;31(6):411-417.
19. Magnusson BO, Sundell SO. Stepwise excavation of deep carious
lesions in primary molars. J Int Assoc Dent Child 1977;8(2):36-40.
20. Leksell E, Ridell K, Cvek M, Mejare I. Pulp exposure after stepwise
versus direct complete excavation of deep carious lesions in young
posterior permanent teeth. Endod Dent Traumatol 1996;12(4):192-196.
21. Falster CA, Araujo FB, Straffon LH, Nor JE. Indirect pulp treatment:
in vivo outcomes of an adhesive resin system vs. calcium
hydroxide for protection of the dentin-pulp complex. Pediatr Dent
2002;24(3):241-248.
22. Al-Zayer MA, Straffon LH, Feigal RJ, Welch KB. Indirect pulp
treatment of primary posterior teeth: a retrospective study. Pediatr
Dent 2003;25(1):29-36.
23. Kreulen CM, de Soet JJ, Weerheijm KL, van Amerongen WE. In
vivo cariostatic effect of resin modified glass ionomer cement and
amalgam on dentine. Caries Res 1997;31(5):384-389.
24. Bonecker M, Toi C, Cleaton-Jones P. Mutans streptococci and lactobacilli
in carious dentine before and after Atraumatic Restorative
Treatment. J Dent 2003;31(6):423-428.
25. Vij R, Coll JA, Shelton P, Farooq NS. Caries control and other
variables associated with success of primary molar vital pulp therapy.
Pediatr Dent 2004;26(3):214-220.
26. Farooq NS, Coll JA, Kuwabara A, Shelton P. Success rates of
formocresol pulpotomy and indirect pulp therapy in the treatment of
deep dentinal caries in primary teeth. Pediatr Dent 2000;22(4):278-286.
27. Oguntebi BR. Dentine tubule infection and endodontic therapy
implications. Int Endod J 1994;27(4):218-222.
28. Black GV. A Work on Operative Dentistry. Volume 2: The Technical
Procedures in Filling Teeth. Chicago: Medico-Dental Publishing
Company; 1908.
29. Oen KT, Thompson VP, Vena D, Caufield PW, Curro F,
Dasanayake A, et al. Attitudes and expectations of treating deep caries:
a PEARL Network survey. Gen Dent 2007;55(3):197-203.
30. Qudeimat MA, Al-Saiegh FA, Al-Omari Q, Omar R. Restorative
treatment decisions for deep proximal carious lesions in primary
molars. Eur Arch Paediatr Dent 2007;8(1):37-42.
31. Black GV. A Work on Operative Dentistry. Volume 1: The
Pathology of the Hard Tissues of the Teeth. Chicago: Medico-Dental
Publishing Company; 1908.
32. Kidd EA. How “clean” must a cavity be before restoration? Caries
Res 2004;38(3):305-313.
33. Bjorndal L, Thylstrup A. A practice-based study on stepwise excavation
of deep carious lesions in permanent teeth: a 1-year follow-up
study. Community Dent Oral Epidemiol 1998;26(2):122-128.
34. Bjorndal L, Larsen T. Changes in the cultivable flora in deep carious
lesions following a stepwise excavation procedure. Caries Res
2000;34(6):502-508.
35. Wilder AD Jr, May KN Jr, Bayne SC, Taylor DF, Leinfelder KF.
Seventeen-year clinical study of ultraviolet-cured posterior composite
Class I and II restorations. J Esthet Dent 1999;11(3):135-142.
36. De Munck J, Van Landuyt K, Peumans M, et al. A critical review
of the durability of adhesion to tooth tissue: methods and results. J
Dent Res 2005;84(2):118-132.
37. Cho BH, Dickens SH, Bae JH, Chang CG, Son HH, Um CM.
Effect of interfacial bond quality on the direction of polymerization
shrinkage flow in resin composite restorations. Oper Dent
2002;27(3):297-304.
38. Lopes GC, Baratieri LN, Monteiro S Jr, Vieira LC. Effect of pos-
JADA, Vol. 139 http://jada.ada.org June 2008 711
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CLINICAL PRACTICE CRITICAL REVIEW
terior resin composite placement technique on the resin-dentin interface
formed in vivo. Quintessence Int 2004;35(2):156-161.
39. Doi J, Itota T, Yoshiyama M, Tay FR, Pashley DH. Bonding to
root caries by a self-etching adhesive system containing MDPB. Am J
Dent 2004;17(2):89-93.
40. Palma-Dibb RG, de Castro CG, Ramos RP, Chimello DT,
Chinelatti MA. Bond strength of glass-ionomer cements to cariesaffected
dentin. J Adhes Dent 2003;5(1):57-62.
41. Yoshiyama M, Tay FR, Doi J, et al. Bonding of self-etch and total-
712 JADA, Vol. 139 http://jada.ada.org June 2008
Copyright © 2008 American Dental Association. All rights reserved.
etch adhesives to carious dentin. J Dent Res 2002;81(8):556-560.
42. Yoshiyama M, Tay FR, Torii Y, et al. Resin adhesion to carious
dentin. Am J Dent 2003;16(1):47-52.
43. Allen KL, Salgado TL, Janal MN, Thompson VP. Removing carious
dentin using a polymer instrument without anesthesia versus a
carbide bur with anesthesia. JADA 2005;136(5):643-651.
44. Pashley EL, Talman R, Horner JA, Pashley DH. Permeability of
normal versus carious dentin. Endod Dent Traumatol 1991;
7(5):207-211.
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3A| 2C| 2B| 2A| 1B| 1A|
Deep or partial caries removal: which is best?
In deep carious lesions, should all infected and affected dentine be removed
prior to restoration?
Thompson V, Craig RG, Curro FA, Green WS, Ship JA.
Treatment of deep carious lesions by complete excavation or partial
removal. A critical review. J Am Dent Assoc 2008; 139:705–712
Data sources Searches for studies were made using the databases:
Medline, Evidence-based Medicine Reviews, Cochrane Database of
Systematic Reviews, Cochrane Central Register of Controlled Trials and
OVID’s Database of Abstracts of Reviews of Effects.
Study selection Only studies reported in English with human
participants were included. Randomised controlled trials (RCT) and
relevant observational studies were included. No other inclusion or
exclusion criteria are described.
Data extraction and synthesis A formal data extraction process
is not described and a qualitative description of the included studies
is provided.
Results Ten articles reporting six studies were included. The results of
three RCT, one with a followup period of 10 years, provide evidence supporting
the practice of leaving behind infected dentine, the removal of
which would risk pulp exposure. A number of other studies show that
cariogenic bacteria, once isolated from their source of nutrition by a
restoration of sufficient integrity, either remain dormant or die and thus
pose no risk to the health of the dentition.
Conclusions There is substantial evidence that, for caries management,
it is not necessary to remove all vestiges of infected dentin from
lesions approaching the pulp.
Address for correspondence: Dr R Craig, Department of Basic Sciences and
Craniofacial Biology, New York University College of Dentistry, 345 East 24th
Street/ 1001S, New York NY 10010-4086, USA. E-mail: rgc1@nyu.edu
SUMMARY REVIEW/RESTORATIVE DENTISTRY
Commentary
Since the days of GV Black, complete caries removal has been
regarded as the gold standard in cavity preparation and, despite
the lack of evidence to support this approach, it remains common
practice today. In deep cavities, the carious process itself and
the trauma of such radical caries removal can cause detrimental
inflammatory changes within the pulp. If such caries removal
leads to exposure of a vital pulp, a direct pulp cap, commonly
using calcium hydroxide, is considered. Although most research
on the direct pulp cap has focussed on the favourable outcome for
traumatically exposed pulps which are healthy prior to the injurious
incident, the prognosis following a carious exposure is not
good: 5- and 10-year success rates of 37% and 13% respectively
have been reported. 1 This critical review is therefore appropriate,
with its systematic search of the literature for evidence that might
elucidate whether complete caries removal and its concomitant
complications is necessary.
Carefully designed prospective RCT provide the strongest evidence
for any intervention. Such trials were the focus of our 2006 Cochrane
review 2 comparing complete or ultraconservative caries removal. The
authors of this paper are correct, however, to draw attention to the
fact that studies of a different design can also add to our understanding
and can often provide compelling evidence for an intervention.
Not including such studies may be regarded by some as “throwing
the baby out with the bathwater”. The aim here was therefore to
extend the search and look for additional studies comparing complete
or partial caries removal. In addition to two RCT included in
the Cochrane review, four further studies were found, specifically
three observational studies and one more RCT.
The main aim of the additional RCT was to investigate the cariostatic
effect of black copper cement when partial caries removal
was carried out in primary teeth. In the partial caries removal group,
the durability of glass ionomer restorations lined with black copper
cement was poor, but glass ionomer restorations alone performed as
well following partial caries removal as they did following complete
caries removal.
Of the three observational studies included here, two were stepwise
excavation in all but name. 3,4 Although other similar clinical studies
on stepwise excavation were not included in the main results of this
paper, they were mentioned in the text (those cited in the Cochrane
review 1 and the review by Bjørndal and Larsen, 2005). Three of these
studies showed that caries that is left and sealed into the tooth after
partial caries removal appears to arrest, so that when the cavities
are re-entered the number of viable organisms within the lesions is
significantly reduced. 3–5
The final study included looked at the success of indirect pulp caps
in primary molar teeth using either a calcium hydroxide lining material
or resin-modified glass ionomer. The success rates presented at
4 years were 89% and 93%, respectively.
www.nature.com/ebd 71

RESTORATIVE DENTISTRY
Although partial caries removal may sit uncomfortably with some
dentists, the authors of this paper also describe a series of studies in
which occlusal caries is arrested by simply fissure-sealing the lesions
with no caries removal at all. Other studies are described that add further
weight to the partial caries removal argument. These all show
that by depriving the organisms within lesions of the intra-oral
substrate they require to survive, both the number and diversity of
organisms decline, with only those able to metabolise pulpal serum
proteins surviving. 6 These organisms are not associated with active
carious lesions, and even pulpal nutrients will decline with time
because of pulp-dentine complex reactions of tubular sclerosis and
reactionary dentine formation.
Unfortunately, it is not clear from this review, or the original
papers, what constitutes deep caries or partial caries removal. Some
authors have described lesions reaching up to halfway to the pulp,
determined on a radiograph, whereas others have given little specific
information other than saying the lesion is deep, or adding that the
extent means pulpal exposure is likely if caries is completely removed.
Similarly, partial caries removal varies from simply bevelling enamel
at the entrance to the fissure to carrying out only peripheral caries
removal and leaving soft infected carious dentine pulpally; to removal
of caries until firm, stained dentine is reached and then placement
of an indirect pulp cap.
The studies cited are therefore heterogeneous, but the evidence
stemming from them all is that removal of all carious tissue is not
necessary. In light of the substantial evidence cited to support partial
caries removal, the authors of this paper point out that there
have, as yet been no studies to prove the desirability of removing all
infected dentine. They conclude that, “before this concept (of partial
removal) is generally accepted by the profession additional clinical
trials may be needed”. This, I am sure, is true. These trials should
be carried out in primary care with detailed, specific information on
lesion extent and what constitutes partial caries removal. The success
of such interventions also needs to be assessed along with research
into techniques for monitoring sealed caries.
David Ricketts
Department of Restorative Dental Care and Clinical Dental
Sciences, University of Dundee Dental School, Dundee, Scotland, UK
1. Barthel CR, Rosenkranz B, Leuenberg A, Roulet JF. Pulp capping of carious exposures:
treatment outcome after 5 and 10 years: a retrospective study. J Endod 2000;
26:525–528.
2. Ricketts DN, Kidd EA, Innes N, Clarkson J. Complete or ultraconservative removal of
decayed tissue in unfilled teeth. Cochrane Database Syst Rev 2006; issue 3.
3. Maltz M, de Oliveira EF, Fontanella V, Bianchi R. A clinical, microbiologic, and
radiographic study of deep caries lesions after incomplete caries removal.
Quintessence Int 2002; 33:151–159.
4. Fairbourn DR, Charbeneau GT, Loesche WJ. Effect of improved Dycal and IRM on
bacteria in deep carious lesions. J Am Dent Assoc 1980; 100:547–552.
5. Bjørndal L, Larsen T. Changes in the cultivable flora in deep carious lesions following
a stepwise excavation procedure. Caries Res 2000; 34:502–508.
6. Paddick JS, Brailsford SR, Kidd EA, Beighton D. Phenotypic and genotypic selection
of microbiota surviving under dental restorations. Appl Environ Microbiol 2005;
71:2467–2472.
Evidence-Based Dentistry (2008) 9, 71-72. doi:10.1038/sj.ebd.6400592
72 © EBD 2008:9.3