Management of the deep carious lesion and the vital pulp dentine complex

lesions are concerned it is currently taughtthat the peripheral aspect of the cavityshould be rendered completely caries free.This should be followed by careful excava-tion of caries at the base of the cavity, overly-ing the pulp until hard, stained dentine isreached,4 thus gradually reducing the bacte-rial load within the cavity. If at final excava-tion the pulp is exposed, the possibility of adirect pulp cap can be evaluated.

Whilst the literature is replete with studieson caries and endodontic procedures, rela-tively little has been published on the rela-tionship between caries and the vitalpulp-dentine complex. This article there-fore aims to review the literature on pulp-dentine complex reactions to caries and the

direct pulp capping technique. It will alsoaim to address when to place a direct pulpcap and when to undertake root canal treat-ment, what materials to use and the long-term prognosis of such a procedure. Moreimportantly, an alternative technique ofcaries removal will be discussed which hasbeen shown to reduce the risk of pulpalexposure.

Dental caries and the pulp dentinecomplex reactionsDental caries in enamel is a subsurface dem-ineralisation caused by acids produced bybacteria in the surface plaque. These acidsdiffuse into the tooth structure causingdemineralisation. It is only when the rela-tively more mineralised surface zone breaksdown that bacteria colonize the enamellesion. At this early stage in the cariousprocess there is some disagreement as towhen the first pulp-dentine complex reac-tions occur. Brännström and Lind (1965)5

for example, found an increase in chronicinflammatory cells beneath lesions appar-ently confined to enamel, whereas othersreport that this only occurs when cariesextends into dentine.6

At the advancing front of a dentine lesion,demineralisation also precedes bacterialinvasion. Considerable demineralisation ofdentine occurs prior to bacterial infection7

and where occlusal lesions are concerned itis only when the caries extends into the mid-dle third of dentine and is radiographicallyvisible that significant infection of the den-tine occurs.8 Fuzayama investigated therelationship between dentine softening, dis-colouration and bacterial infection andfound that softening preceded discoloura-tion which in turn preceded bacterial inva-sion.9 Thus bacterial acids and products,such as proteases, diffuse ahead of the bacte-ria towards the pulp and a number of factorsinfluence the rate at which this occurs.These are namely the concentration of bac-terial by-products, the permeability of thedentine and the pulpal fluid pressure.10

The frequency of sugar consumption andhence acid provoking attacks will affect the

606 BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001

PRACTICErestorative dentistry

Trauma, rapidly progressing caries orover zealous removal of caries can result

in exposure of the dental pulp. In these situ-ations a direct pulp capping technique canbe considered in an attempt to preserve thevitality of the pulp and to stimulate it to pro-duce a calcific barrier to wall off the expo-sure. However, the health of the pulp and itshealing capacity will depend on a number offactors, including the precipitating eventleading to the exposure.

Following trauma, when a previouslysound, asymptomatic tooth suffers a coro-nal fracture involving the pulp, it is widelyaccepted that the direct pulp cap is the treat-ment of choice, providing the exposure issmall and is treated within 24 hours.1,2,3 Inthis situation the depth of damage to thepulp tissue is small and the relatively healthypulp tissue has considerable reparativepotential, particularly in young teeth withimmature apices and a good blood supply.However, the caries process can lead tomarked changes within the pulp-dentinecomplex, which can vary considerablydepending on the severity of the disease andthe age of the pulp. Where deep dentine

Management of the deep carious lesionand the vital pulp dentine complexD. Ricketts,1

This article describes the relationship between the carious processand pulp-dentine complex reactions. Where the balance betweenthe two is in favour of the carious process and where conventionalcavity preparation leads to a direct pulp exposure, the direct pulpcap technique is described. The success of the technique isaddressed and more importantly an alternative technique for cariesremoval, namely stepwise excavation, is described which may lead toa reduced risk of carious exposure and the need for the direct pulpcap technique.

1Clinical Lecturer, Unit of Comprehensive RestorativeCare, Dundee Dental Hospital, Park Place, DundeeDD1 4HR*Correspondence to: David Rickettsemail: [email protected] PAPER

Received 27.02.01; Accepted 16.07.01© British Dental Journal 2001; 191: 606–610

In brief• The direct pulp cap, whilst

predictable for the traumaticallyexposed pulp, has a questionable longterm prognosis where a cariousexposure is concerned

• The activity of a deep carious lesionin dentine can be preferentiallymodified, by sealing in the dentinecaries. This allows reparative pulp-dentine complex reactions to takeplace

• When such lesions are re-enteredafter six months or more the risks ofdirectly exposing the pulp arereduced

BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001 607


concentration of acid produced in the den-tal plaque. This in turn will be moderated tosome extent by saliva or whether the lesionis open (frank cavitation) or closed, but ingeneral the more acid produced the greaterthe concentration gradient toward the pulp.

The permeability of the dentine, whichresists this inward diffusion of acid, changeswith age. Newly erupted teeth are more per-meable and less mineralised allowing therapid diffusion of acids. As such they may bemore susceptible to rapidly progressingcaries. Pulp dentine complex reactions tothis stimulus are aimed at reducing the per-meability of the dentine. The most commonreaction depends upon a vital odontoblastprocess and is the deposition of apatite andwhitlockite crystals within the dentinaltubules leading to dentine tubule sclerosis.In addition to this, tertiary dentine may alsobe laid down by the odontoblast within thepulp chamber.10

If the carious process proceedsunchecked, degenerative changes within theodontoblasts take place before inflamma-tory changes within the pulp occur.11 Thiscan lead to complete cell death and replace-ment by odontoprogenitor cells from thesubjacent cell rich layer. Differentiation ofthese mesenchymal cells into odontoblast-like cells, can lead to the production ofreparative dentine which, depending on theseverity of the carious lesion, can be irregu-lar with cellular inclusions or if less aggres-sive 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 ahealthy pulp, however if the carious processcontinues unchecked pulpal inflammationwill ensue. In an attempt to evaluate therelationship between lesion depth and pul-pal inflammation, Reeves and Stanley(1966) showed that if the advancing front ofthe lesion was about 1 mm from the pulpthen no significant disturbance occurred.12

However, once within 0.5 mm of the pulpmore pathological changes occur, but it wasonly when the reactionary dentine itself wasinvolved 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 hyper-aemia and pulpitis occurred.7

Thus in final excavation of soft pulpalcaries, if direct perforation of the pulp occursthe relative rate of progression of the lesionhas been faster than the rate of pulp-dentinereactions. At this stage the pulp is likely to beinflamed and the decision of whether to placea direct pulp cap has to be made.

The direct pulp cap.A direct pulp cap usually involves the place-ment of a calcium hydroxide preparationdirectly in contact with an exposed pulp.For a direct pulp cap to be successful a num-ber of factors have to be met and these aredetailed in Table 1. Lin and Langland (1981)have shown that teeth with a history of painwill have an area of necrosis within the pulpchamber and for many this will extend intothe root canal.13 Bacterial invasion of pulptissue is closely related to this necrosis and assuch these teeth should be endodonticallytreated. Teeth exposed during cariesremoval will inevitably have some degree ofinflammation although the histologicalextent of this cannot be accurately predictedfrom a clinical examination. Table 1 pro-vides sensible but not infallible clinical cri-teria for successful direct pulp capping.

It was once thought that only pinpointexposures could be pulp capped, howevermore recent research would suggest that thesize of exposure has no bearing on clinicaloutcome.14,15,16 Whilst these studies per-tain to traumatically exposed pulps, Mejareand Cvek (1993) have suggested that deepcarious exposures be opened up so that 1 mm–3 mm of exposed pulp can be

removed.17 It is important to draw attentionto the fact that this study was on young pos-terior teeth and cannot be regarded as a truedirect pulp cap, but rather a partial pulpo-tomy. This procedure has a number ofadvantages; it reduces the potential forintroduction of dentine chips into the pulptissue and it enables good contact betweenpulp and capping agent. It has been shownthat dentine chips inadvertently pushedinto the pulp tissue cause severe inflamma-tory reaction, which can lead to pulp necro-sis.18,19 It also removes superficiallycontaminated pulpal tissue.

It is important to emphasize that whilstthe size of traumatic exposures is not soimportant, carious exposures should besmall even if they are opened up further atoperation. It is generally agreed that largercarious exposures have a poor prognosis dueto a more severely inflammed pulp, risk ofnecrosis and bacterial contamination.20,21,22

The issue of age is also difficult, as there isno clear cut-off when a direct pulp capshould no longer be considered. The ageingprocess is gradual and with increased age thepulp tissue becomes more fibrous with areduction in pulp volume as a result of physi-ological secondary dentine formation andreactionary dentine due to external stimulisuch as trauma, caries and tooth wear. Theblood supply to the dental pulp is critical toits health and regenerative capacity, and asthis decreases with age so does its capacity torespond to a direct pulp cap. Hence ratherthan a chronological age as a cut-off, the bio-logical age of an individual tooth should beassessed and a previous restorative historytaken into consideration as well as the factorsin Table 1.

History Preoperative assessment Clinical findings.No recurring or Normal vitality tests. Pink pulpspontaneous 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.

Table 1 Criteria essential for a successful direct pulp cap.



Finally the location of the exposure isimportant as there should be no pulp tissuecoronal to the exposure. Exposure in a cer-vical cavity would lead to reactionary den-tine formation which would restrict theblood supply to the tissue more coronal toit, leading to necrosis and failure. Theseteeth should therefore be root treated.23

Calcium hydroxide to date remains thematerial of choice for a direct pulp cappingtechnique in general practice. Its propertiesand mode of action have been comprehen-sively reviewed previously.24 However, a rel-atively new material, mineral trioxideaggregate (MTA) has been investigated.25 Itconsists of fine hydrophilic particles, whichwhen mixed with sterile water results in acolloidal gel of pH 12.5. This gel solidifies toa hard structure within approximately 4hours. Once set, it has a high compressivestrength comparable to IRM or Super EBA.Both laboratory and clinical studies haveshown this material to be extremely bio-compatable with pulp tissue and to havegood sealing ability against dyes and bacte-ria. In a limited study, Pitt-Ford et al.,showed that direct pulpal exposures treatedwith MTA demonstrated more predictabledentine bridge formation than calciumhydroxide.26 It would therefore appear thatthis material may be the material of choicefor future pulp caps. However, problemsassociated with the material’s difficult han-dling properties and prolonged setting timemay preclude its widespread acceptancedespite its superior therapeutic properties.

What is the success rate of the pulpcap technique?The success rate of a direct pulp cap is diffi-cult to establish from the dental literature asstudies fail to clearly identify whether expo-sures were due to trauma or caries27 oraddress those resulting from trauma only.28

Whilst the prognosis of teeth that havereceived direct pulp caps as a result oftrauma would appear good28 those with acarious exposure fare less well.29 In a retro-spective study of 123 direct pulp caps oncarious exposures only 37% were clearlysuccessful after 5 years and after 10 years80% had failed.29 Loss of pulp vitality inthese teeth poses a problem as a significant

amount of physiological secondary andreactionary dentine would have developedwhich has the potential to complicate subse-quent root canal treatment. In addition theroot canal system may have become infectedand prognosis for root treatment is lessfavorable than if vital pulp tissue wereremoved.30 These results question the suc-cess of the direct pulp cap for carious expo-sures. However, a further thorough audit isrequired, as only 123 out of a possible 401teeth with a direct pulp cap were availablefor 10 year follow up.29

The indirect pulp cap.When caries is thought to extend close to,or into the pulp, excavation of the pulpalcaries can be stopped at stained but firmdentine.31 Calcium hydroxide lining isapplied over the pulpal dentine prior toplacement of the definitive restoration.This is classically referred to as the indirectpulp cap. The difficulty with this techniqueis knowing how rapid the carious processhas been, how much tertiary dentine hasbeen formed and knowing exactly when tostop excavating to avoid pulp exposure.Using a stepwise approach to cariesremoval these parameters can be regulatedwith a more predictable outcome.

Stepwise excavation.It could be argued that in the absence of anysigns and symptoms of pulpitis, and wherethe criteria in Table 1 are met, it is over-judi-cious removal of caries that leads to a pulpalexposure. In the majority of cases this can beavoided if a stepwise approach to cariesremoval is adopted. This approach which isnot completely new,32 has recently been thesubject of renewed interest. Bjørndal et al.(1997)33 investigated 31 teeth with grosscaries, which from a clinical and radi-ographic examination were thought to havecarious pulpal exposures. In these teethcaries removal was staged over two separateappointments 6–12 months apart. At thefirst appointment, access to the caries wasgained and the periphery of the cavity madecompletely caries free. Soft, wet and palecoloured dentine was left pulpally, whichhas previously been shown to be heavilyinfected.34 The cavity was lined with cal-

cium hydroxide and restored with glassionomer and left for 6–12 months.

After this period, cavities were re-enteredand the dentine in all teeth was found to bedarker in colour, harder and drier in consis-tency. Microbiological analysis also showed asignificant reduction in cultivable micro-organisms over the period in which the pro-visional restorations were in place. Thesefindings would imply that by removing someof the carious biomass and sealing theremaining caries from extrinsic substrate andoral bacteria, the caries left behind after thefirst excavation had become less active. Thisallows time for pulp-dentine complex reac-tions to take place so that at the second exca-vation visit, there is less likelihood of pulpalexposure. It has also been suggested that bychanging the cavity environment from anactive lesion into the condition of a moreslowly progressing lesion, this will be accom-panied by more regular tubular tertiary den-tine formation. The success of this techniquehas been demonstrated in a randomized con-trolled study comparing conventional cavitypreparation of such lesions with stepwiseexcavation.35 Using the stepwise excavationtechnique significantly fewer teeth hadexposed pulps (17.5%) compared with con-ventional caries removal (40%). Theseresults were echoed in a similar study of deepcarious lesions in primary teeth.36 In thisstudy 55 teeth were treated with the stepwiseexcavation technique and 55 control teethwere prepared conventionally. The propor-tion of teeth where pulpal exposure occurredwere 15% and 53% respectively. The tech-nique has also been shown to be successful ina practice-based study37 where only 5.3% ofpulps were exposed.

Leaving heavily infected caries, thedilemma.The thought of leaving heavily infected cari-ous dentine for 6–12 months would seemcontrary to teaching in dental schools. It hasbeen taught that when a restoration isplaced, the presence and severity of pulpalinflammation is related to the level of bacte-rial microleakage around the restora-tion.38–41 Thus it would be logical to thinkthat leaving dentine caries which is heavilyinfected would result in similarly severe pul-

BRITISH DENTAL JOURNAL, VOLUME 191, NO. 11, DECEMBER 8 2001 609


tion of new dental materials, demand fur-ther research into this subject, particularlywhere older more compromised teeth areconcerned.

1 Cox C F, Bergenholtz G, Heys D R, Syed A,Fitzgerald M, Heys J R. Pulp capping of dental pulp mechanically exposed to oralmicroflora: a 1–2 year observation of woundhealing in monkey. J Oral Pathol 1985; 14:156–168.

2 Heidi S, Kerekes K. Delayed direct pulpcapping in permanent incisors of monkeys. Int Endo J 1987; 20: 65–74.

3 Pitt Ford T R, Roberts G J. Immediate anddelayed direct pulp capping with the use of anew visible light-cured calcium hydroxidepreparation. Oral Surg Oral Med Oral Pathol1991; 71: 338–342.

4 Kidd E A M, Smith B G N. Pickard’s Manual ofOperative Dentistry. 7th Edition pp 58–59.Oxford: Oxford University Press; 1996.

5 Brännström M, Lind P O. Pulpal response toearly 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 ofvisual, radiographic and electronic diagnosis ofocclusal caries in non-cavitated teeth judged tobe in need of operative care. Br Dent J 1995;179: 214-220.

9 Fuzayama T, Okuse K, Hosoda H. Relationshipbetween hardness, discoloration and microbialinvasion in carious dentin. J Dent Res 1966; 45:1033–1046.

10 Kim S, Trowbridge H O. Pulpal reaction tocaries and dental procedures. In Cohen S,Burns R C, Rudolph P. (eds) Pathways of thepulp. 7th Ed. pp532–534. Missouri: Mosby Inc;1998.

11 Trowbridge H O. Pathogenesis of pulpitisresulting from dental caries. J Endod 1981; 7:52–60.

12 Reeves R, Stanley H R. The relationship ofbacterial penetration and pulpal pathosis incarious teeth. Oral Surg 1966; 22: 59–65.

13 Lin L, Langeland K. Light and electronmicroscopic study of teeth with carious pulpexposures. Oral Surg 1981; 51: 292–316.

14 Fuks A B, Cosack A, Klein H, Eidelman E.Partial pulpotomy as a treatment alternative forexposed pulps in crown-fractured permanentincisors. 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 complicatedcrown fracture in permanent incisors: a clinicaland radiographic study. J Pedodont 1985; 9:

142–147.

pal inflammation. However, teeth that havebeen treated with the stepwise excavationtechnique do not show any signs or symp-toms of pulpitis. The difference here may liein the fact that in the animal studies investi-gating the effects of bacterial microleakage,cavities have been prepared in sound teeth.The pulp therefore has not had any oppor-tunity to mount its protective reaction andthe presence of bacteria and their by-prod-ucts are in contact with dentine whosetubules are potentially patent and pulp vul-nerable. To the contrary, there is now a sig-nificant amount of evidence to support thefact that there are few adverse effects, andpotential benefits when caries is ‘sealed into’a tooth. These studies can be divided intothose where caries has been ‘sealed in’ with asimple fissure sealant and those where ultra-conservative caries removal has been followed by placement of a compositerestoration over active caries.

Fissure sealant studies.When occlusal caries is visible radiographi-cally, the lesion extends into the middle thirdof dentine42 and is heavily infected.8 Studieshave shown that when a fissure sealant isplaced over such lesions there is a significantreduction in the number of cultivablemicroorganisms.43–48 Such lesions appear toarrest and no increase in lesion size has beenfound radiographically over a period of twoyears.49 In addition no study has reportedsymptoms of pulpitis or loss of vitality.

Ultraconservative caries removal.Perhaps some of the most compelling evi-dence is provided by Mertz-Fairhurst et al.,who in 1998 presented ten year data on 156ultraconservative, cariostatic sealed restora-tions.50 In this study, teeth with clinical andradiographic evidence of occlusal caries wereminimally prepared by placing a 45°– 60°bevel in the enamel, surrounding a franklycavitated lesion. The bevel was at least 1 mmwide and placed in sound enamel. Noattempt was made to remove any cariousdentine and the resultant ‘cavities’ wererestored with acid etched composites andcovered with fissure sealant. Although anumber of these teeth have been lost from thestudy due to patients failing to return for

recall, 85 have been followed throughout theten years. Various progress reports on thestudy sample have shown that sealing cariesinto the tooth arrests the progress of thelesion by effectively eliminating the oralsource of substrate to the bacteria within thelesion.51-55 Only one restoration appeared to‘cave-in’, only one succumbed to secondarycaries and 3.5% showed signs of wear. All theteeth remained symptomless with no signs ofpulpal inflammation or necrosis.50

Why re-enter?The success of this technique is dependentupon the integrity of the restoration and itsseal. Regular recall would be essential. In theMertz-Fairhurst et al. study (1998) the regu-lar recall would identify any lost restorationat an early stage. However, over the ten yearperiod between 18% and 45% of patientsfailed to attend for annual recall.50 In theunlikely event that the restoration shouldfail and not be detected, the potentially re-activated lesion would already be in anadvance stage. Following sealing caries intothe tooth, the carious dentine becomes dry,harder and darker in colour.33 As a resultthere is shrinkage of the tissue leaving a voidbeneath the restoration. These two factorssupport the second stage of the stepwiseexcavation. However, the work by Mertz-Fairhurst et al. (1998)50 would suggest thatthe interval between first and second exca-vation is not critical and could be left forconsiderably longer than 6–12 months.

Thus use of a more conservative techniquefor removing caries in a young patient withvery deep lesions could eliminate the need forthe conventional direct pulp cap technique.In those rare instances when this is stillrequired, adoption of the stepwise excavationtechnique should result in a minimallyinflamed pulp, superior tertiary dentine for-mation, less bacterial load and a more pre-dictable pulp cap. Where this is required theuse of calcium hydroxide, whilst acceptable atpresent, may become superceded by a min-eral trioxide aggregate material.

ConclusionThese are exciting times when the conven-tional wisdom of caries removal is beingchallenged.56 This together with the evolu-



17 Mejare I, Cvek M. Partial pulpotomy in youngpermanent teeth with deep carious lesions.Endodont Dent Traumatol 1993; 9: 238–242.

18 Kalins V, Frisbie H E. Effect of dentinefragments 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 pulpexposures: an ultrastructural study. J OralPathol 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 deepcaries, vital pulp exposure, and pulpless teeth inchildren. In McDonald R E, Avery D R, (eds).Dentistry for the child and adolescent. 3rd ed. StLouis: Mosby, 1978.

22 Seltzer S, Bender I B. Pulp capping andpulpotomy. In Seltzer S, Bender I B (eds). Thedental pulp, biologic considerations in dentalprocedures. 2nd ed. Philadelphia: Jb Lippincott,1975.

23 Stanley H R, Lundy T. Dycal therapy for pulpexposure. Oral Surg Oral Med Oral Pathol.1972; 34: 818–827.

24 Forman P C, Barnes I E. A review of calciumhydroxide. Int Endod J 1990; 23: 283–297.

25 Torabinejad M, Chivian N. Clinical applicationsof 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 mineraltrioxide 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 pulpotomyand capping with calcium hydroxide inpermanent incisors with complicated crownfracture. 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: aretrospective study. J Endodon 2000; 26:525–528.

30 Sjögren U, Hagglund B, Sundqvist G, Wing K.Factors affecting long term results ofendodontic treatment. J Endodon 1990; 16:498–504.

31 Kidd E A M, Smith B G N. Pickard’s Manual ofOperative Dentistry. 7th Edition p 59. Oxford:Oxford University Press; 1996.

32 King J B, Crawford J J, Lindahl R L. Indirectpulp capping: a bacteriologic study of deepcarious dentine in human teeth. Oral Surg OralMed Oral Pathol 1965; 20: 663–671.

33 Bjørndal L, Larsen T, Thylstrup A. A clinicaland microbiological study of deep cariouslesions during stepwise excavation using longtreatment intervals. Caries Res 1997; 31:411–417.

34 Kidd E A M, Ricketts D N J, Beighton D.Criteria for caries removal at the enameldentine junction: a clinical and microbiologicalstudy. Br Dent J 1996; 180: 287–291.

35 Leksell E, Ridell K, Cvek M, Mejare I. Pulpexposure after stepwise versus direct completeexcavation of deep carious lesions in youngposterior permanent teeth. Endod DentTraumatol 1996; 12: 192–196.

36 Magnusson B O, Sundell S O. Stepwiseexcavation of deep carious lesions in primarymolars. J Int Ass Dent Child 1977; 8: 36–40.

37 Bjørndal L, Thylstrup A. A practice-basedstudy on stepwise excavation of deep cariouslesions in permanent teeth: a 1 year follow-upstudy. 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: itseffect 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 surface-sealed dental materials against exposed pulps.J Pros Dent 1987; 57: 1–8.

40 Cox C F, Sübay R K, Suzuki S, Suzuki S H, OstroE. Biocompatability of various dental materials:pulp healing with a surface seal. Int J PeriodontRest Dent 1996; 16: 241–251.

41 Grieve A R, Alani A, Saunders W P. The effectson the dental pulp of a composite resin and twodentine bonding agents and associatedbacterial 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 diagnosisof occlusal caries: a study in vitro. J Oral Rehabil1995; 22: 15–20.

43 Handelman S L, Buonocore M G, Heseck D J. Apreliminary report on the effect of fissuresealant on bacteria in dental caries. J ProsthetDent 1972; 27: 390–392.

44 Handelman S L, Buonocore M G, Schoute P C.

Progress report on the effect of a fissure sealantin 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 indental caries. J Am Dent Assoc 1976; 93:967–970.

46 Going R E, Loesche W J, Grainger D A, Syed SA. The viability of micro-organisms in cariouslesions five years after covering with a fissuresealant. J Am Dent Assoc 1978; 97: 455–462.

47 Jensen O E, Handelman S L. Effect of anautopolymerising sealant on viability ofmicroflora in occlusal dental caries. Scand JDent Res 1980; 88: 382–388.

48 Mertz-Fairhurst E J, Schuster G S, Fairhurst CW. Arresting caries by sealants: results of aclinical 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 ofsealed carious and sound tooth surfaces. J AmDent Assoc 1986; 113: 751–754.

50 Mertz-Fairhurst E J, Curtis J W, Ergle J W,Rueggeberg F A, Adair S M. Ultraconservativeand cariostatic sealed restorations: results atyear 10. J Am Dent Assoc 1998; 129: 55–66.

51 Mertz-Fairhurst E J, Call-Smith K M, SchusterG S, et al. Clinical performance of sealedcomposite restorations placed over cariescompared with sealed and unsealed amalgamrestorations. 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 JDent 1992; 5: 5–10.

54 Mertz-Fairhurst E J, Smith C D, Williams J E, et al. Cariostatic and ultraconservative sealedrestorations: six year results. Quintessence Int1992; 23: 827–838.

55 Mertz-Fairhurst E J, Adair S M, Sams D R, et al.Cariostatic and ultraconservative sealedrestorations: nine-year results among childrenand adults. ASDC J Dent Child 1995; 62:97–106.

56 Kidd E. Caries removal and the pulpo-dentinalcomplex. Dent Update 2000; 27; 476–482.

2008;139;705-712 J Am Dent Assoc

Curro, William S. Green and Jonathan A. Ship Van Thompson, Ronald G. Craig, Fredrick A.

reviewexcavation or partial removal: A critical Treatment of deep carious lesions by complete

jada.ada.org ( this information is current as of October 20, 2008 ):The following resources related to this article are available online at

http://jada.ada.org/cgi/content/full/139/6/705found in the online version of this article at:

including high-resolution figures, can beUpdated information and services

http://www.ada.org/prof/resources/pubs/jada/permissions.aspreproduce this article in whole or in part can be found at:

of this article or about permission toreprintsInformation about obtaining

© 2008 American Dental Association. The sponsor and its products are not endorsed by the ADA.

on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org/cgi/content/full/139/6/705

http://www.ada.org/prof/resources/pubs/jada/permissions.asp

http://jada.ada.org

The treatment of deep car-ious lesions approachinga healthy pulp presents asignificant challenge tothe practitioner. The tra-

ditional management of cariouslesions of any kind dictates theremoval of all infected and affecteddentin to prevent further cariogenicactivity and provide a well-mineralized base of dentin for resto-ration. When the procedure risksexposing or even breaching thepulp, however, the course of treat-ment becomes less predictable andmay require such measures as indi-rect pulp capping (typically using aprotective material such as a cal-cium hydroxide–based preparation),pulpotomy or, in the most extremecases, pulpectomy. Choosing amongthese options can be daunting forthe dentist—as well as for thepatient, who is advised of the risksand asked to share in the decision.

To preclude or at least minimizethe potential complications of com-

Dr. Thompson is a professor and the chair, Department of Biomaterials and Biomimetics, and the director, Protocol Development and Training Core, PractitionersEngaged 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 thedirector, Information Dissemination Core, PEARL Network, New York University College of Dentistry. Address reprint requests to Dr. Craig at New York UniversityCollege of Dentistry, 345 E. 24th Street/1001S, New York, N.Y. 10010-4086, e-mail “[email protected]”.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 professorof medicine, New York University School of Medicine; and the director, PEARL Network, New York University College of Dentistry, New York City.

Treatment of deep carious lesions by complete excavation or partial removalA critical review

Van Thompson, DDS, PhD; Ronald G. Craig, DMD, PhD; Fredrick A. Curro, DMD, PhD; William S. Green, AB; Jonathan A. Ship, DMD

CLINICAL PRACTICE CRITICAL REVIEW

JADA, Vol. 139 http://jada.ada.org June 2008 705

Background. The classical approach to treatment of deep cariouslesions approaching the pulp mandates removing all infected and affecteddentin. Several studies call this approach into question.Types of Studies Reviewed. A search of five electronic databasesusing selected key words to identify studies relating to partial versus com-plete removal of carious lesions yielded 1,059 reports, of which the authorsjudged 23 to be relevant. Three articles reported the results of randomizedcontrolled trials.Results. The results of three randomized controlled trials, one of whichfollowed up patients for 10 years, provide strong evidence for the advis-ability of leaving behind infected dentin, the removal of which would putthe pulp at risk of exposure. Several additional studies have demonstratedthat cariogenic bacteria, once isolated from their source of nutrition by arestoration of sufficient integrity, either die or remain dormant and thuspose no risk to the health of the dentition.Clinical Implications. There is substantial evidence that removingall vestiges of infected dentin from lesions approaching the pulp is notrequired for caries management.Key Words. Deep caries; deep carious lesions; partial caries removal;indirect pulp capping; pulpal exposure; stepwise excavation; alternativerestorative treatment.JADA 2008;139(6):705-712.

A B S T R A C T

Copyright © 2008 American Dental Association. All rights reserved.

on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

plete excavation of carious dentin close to thepulp, several authors have investigated and pro-posed alternative approaches. One such method,stepwise (or two-step) excavation, involves thestaged removal of carious tissue. At the patient’sinitial visit, once the clinician has establishedthat the pulp still is vital, he or she partiallyremoves necrotic infected dentin, often character-ized as soft and removed easily by using handinstruments. The clinician then seals the lesionwith a medicament such as calcium hydroxideand places a temporary restoration. At the secondvisit—typically some months after the first and,in some cases, up to two years later—the clinicianremoves all or most of the remaining infectedtissue. The rationale for this approach is that bythis point any remaining bacteria will have died,residual infected dentin as well as affected dentinwill have remineralized, and reparative dentinwill have been generated, making it easier for thedentist to remove any remaining carious tissue.

An even more controversial approach is conser-vative or ultraconservative removal of carioustissue, often referred to as “partial cariesremoval.” In this method, the practitionerremoves most but not all of the infected dentin,seals the cavity (with or without indirect pulptreatment) and proceeds with the restoration. Thetradeoff for avoiding pulpal exposure—leavingbehind a layer of infected dentin—is defended byciting the substantial evidence (discussed below)that cariogenic bacteria isolated from their sourceof nutrition by a restoration of sufficient integrityeither die or remain quiescent and thus, given a vital pulp, pose no risk to the health of the dentition.

Studies comparing either partial cariesremoval or stepwise excavation with completeremoval of infected tissue from deep cariouslesions were the subject of a 2006 CochraneReview.1 The Cochrane article, while extremelyvaluable, is limited in scope by virtue of being ameta-analysis focused solely on the results of ran-domized controlled trials. In preparing thisreview, we sought to cast a wider net by per-forming a traditional review, taking into accountobservational studies and ancillary investigationsthat also might be of interest to the practitioner.

METHODS

We conducted a systematic search of five data-bases (MEDLINE, Evidence-Based MedicineReviews, the Cochrane Database of Systematic

Reviews, Cochrane Central Register of ControlledTrials and OVID’s Database of Abstracts ofReviews of Effects) using the following key words:deep caries; deep carious lesions; partial cariesremoval; indirect pulp capping; pulpal exposure;stepwise excavation; alternative restorative treat-ment (ART). We limited the search to reportswritten in English describing studies usinghuman subjects and published from 1950 throughthe first week of November 2007. The literaturesearch yielded 1,059 articles, of which 23—including articles relating to restorationlongevity, cariogenic activity and pulp vitality, aswell as those directly addressing partial versuscomplete removal of deep carious lesions—reported results we deemed directly relevant.

RESULTS

We identified 10 articles2-11 accounting for sixstudies (four of these articles reported follow-upresults) that directly address the issue of partialremoval of carious tissue from deep lesions(Table). Three investigations stood out by virtueof being randomized controlled trials: the 1987study by Mertz-Fairhurst and colleagues,2 the1999 study by Ribeiro and colleagues5 and the2004 study by Foley and colleagues.6

Mertz-Fairhurst and colleagues2 used a ran-domized split-mouth, four-celled design to com-pare sealed composite restorations in teethtreated via partial caries removal with bothsealed and unsealed amalgam restorations inteeth from which all carious tissue had beenremoved. The study population consisted of 123patients aged 8 to 52 years who had at least onepair of frank Class I lesions that, according to theinvestigators’ radiographic evaluation, extendedas far as halfway from the dentinoenamel junc-tion (DEJ) to the pulp. A total of 156 pairs (312teeth) were included in the study. The investiga-tors evaluated restorations radiographically aswell as clinically (using a modification of theRyge/Snyder criteria12) at six months, one yearand two years after treatment. They detected nosignificant differences among the three treat-ments—sealed conservative, sealed amalgam,unsealed amalgam—at any period. Mertz-


706 JADA, Vol. 139 http://jada.ada.org June 2008

ABBREVIATION KEY. ART: Alternative restorativetreatment. CFU: Colony-forming unit. DEJ: Dentino-enamel junction. GIC: Glass ionomer cement. PEARL: Practitioners Engaged in Applied Researchand Learning.


on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

Fairhurst’s group followed up these patientsacross the next decade,3,4 finally observing that“the bonded and sealed composite restorationsplaced over the frank cavitated lesions [had]arrested the clinical progress of these lesions for10 years.”4

The randomized controlled trial conducted byRibeiro and colleagues,5 in which they evaluatedthe performance of a dentin adhesive system, alsoserved to test the relative performance of com-

plete and partial caries removal. After etching,the investigators applied a bonding agent to bothcarious and noncarious dentin in 48 primarymolars of 38 children aged 7 to 11 years. In onegroup, the clinicians removed carious dentin com-pletely from the DEJ but only superficially fromthe remainder of the cavity; they treated a secondgroup by completely excavating caries. The inves-tigators extracted 40 teeth (20 from each group)at about the time of exfoliation (approximately



TABLE

Summary of studies examining partial caries removal.STUDY STUDY DESIGN FOLLOW-UP PERIOD RESULTS

Randomized Controlled Trials

Mertz-Fairhurst and colleagues2-4 Split-mouth randomizedtrial of 156 pairs of teeth,in subjects aged 8 through52 years, comparing sealedresin-based compositesafter partial caries removalversus sealed and unsealedamalgams after completecaries removal

Clinical and radi-ographic follow-up atsix months and at one,two, five and 10 years

No differences noted amonggroups at any time offollow-up

Ribeiro and colleagues5 Randomized controlledtrial of 48 primary molars,in subjects aged 7 through11 years, restored with aresin-bonded composite,comparing partial versuscomplete caries removal

Extracted near time ofexfoliation and exam-ined radiographicallyand via electronmicroscopy

No differences notedbetween groups

Foley and colleagues6 Split-mouth randomizedcontrolled trial of 88 teethin 44 subjects aged 3.7through 9.5 years; teethdivided into four groups:complete or partial cariesremoval restored withcopper phosphate cementwith or without glassionomer cement oramalgam

Restorations assessedclinically at six-monthintervals for 24months and radi-ographically at 12 and24 months

Use of copper phosphatecement plus glass ionomercement resulted in moreabscess or sinus formation;use of glass ionomer cementalone resulted in no differ-ences between groups

Observational Studies

Fairbourn and colleagues10 Observational study of theeffect on cultivatable floraafter partial caries removalfollowed by zinc oxideeugenol with or withoutcalcium hydroxide base in40 permanent teeth

At reentry after fivemonths, the remaininginfected dentin wasremoved and culti-vated for microbiolog-ical analysis

Nine of 20 teeth treatedwith calcium hydroxide andfive of 20 teeth treated withzinc oxide–eugenol weresterile

Maltz and colleagues7,9, Oliveira and colleagues8

Observational study of par-tial caries removal in 32subjects aged 12 through23 years

Clinical, radiographicand microbiologicaldata collected atreentry at six to seven,14 to 18, and 36 to 45months after treatment

Remineralization occurredand caries was arrested ateach of the three times offollow-up

Marchi and colleagues11 Observational study of theeffect of calcium hydroxideand resin-modified glassionomer liners on indirectpulp caps of 27 primarymolars in subjects aged 4through 9 years

Examined at fouryears for clinical orradiographic evidenceof pulp pathology

88 percent success for cal-cium hydroxide and 93 per-cent success for resin-modified glass ionomer


on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

one year after treatment) and subjected the teethto radiographic and scanning electron microscopicanalysis. These results, as well as evaluations ofretention rates, marginal integrity and pulpalsymptoms, indicated no significant differencesbetween the two groups.

A more recent study by Foley and colleagues6

compared the cariostatic effectiveness of alterna-tive restorative materials in both partial and com-plete removal of carious tissue. The authors useda split-mouth design in 44 patients aged 3.7 to 9.5years who had at least one pair of previouslyunrestored primary molars that had no pulpalinvolvement. They treated one tooth of each pairby complete caries removal and the other byincomplete caries removal followed by restorationusing copper phosphate cement, glass ionomercement (GIC) or both, or a material “of the oper-ator’s choice” (such as amalgam). At 24 monthsafter treatment, teeth that had undergone partialcaries removal followed by restoration withcopper phosphate cement and GIC exhibitedgreater abscess or sinus formation than did teeththat had undergone other treatments. Restora-tions placed in teeth treated with GIC alone afterpartial caries removal, however, exhibited a dura-bility and effectiveness comparable with thoseplaced in teeth that had undergone completecaries removal.

In an observational study, Maltz and col-leagues7 investigated the effects of partial cariesremoval in 32 teeth with deep carious lesions. Onthe basis of clinical, radiographic and microbio-logic evidence at reentry six to seven months aftertreatment (after which they placed a permanentrestoration), the authors concluded that reminer-alization had taken place and that caries hadbeen arrested. In follow-up studies of the samepatients, the authors reported similar results 14to 18 months after treatment8 and 36 to 45months after treatment.9

Fairbourn and colleagues10 reported the effectof indirect pulp capping, after partial cariesremoval, on cultivable aerobic and anaerobic bac-teria. These investigators restored 40 permanentasymptomatic teeth that had carious occlusal orinterproximal lesions approaching the pulp afterpartial excavation of infected dentin in which zincoxide–eugenol (Caulk IRM Intermediate Restora-tive Material, Dentsply Caulk, Milford, Del.) withor without a calcium hydroxide base (Dycal,Dentsply Caulk) was used. After five months,they isolated the teeth, excavated the remaining

infected dentin and cultivated it to identify bacte-rial species. Both groups showed a dramaticdecrease in colony-forming units (CFUs); nine of20 teeth treated with the calcium hydroxide linerand five of 20 teeth treated with zinc oxide–eugenol had become operationally sterile (< 300CFUs per milligram of dentin). The authors con-cluded that reentry to remove residual infecteddentin with either restorative material may beunnecessary, provided that the restoration main-tains an effective seal.

Marchi and colleagues11 studied the effective-ness of two protective liners, calcium hydroxideand resin-modified glass ionomer, in the indirectpulp treatment of 27 primary molars. At fouryears after treatment, the success rate using theformer was 88.8 percent and using the latter was93 percent. The investigators defined “success”essentially as the absence of any “clinical radio-graphic signs or symptoms of irreversible pulppathologies or necrosis.” The authors concludedthat “indirect pulp capping in primary teetharrests the progression of the underlying caries,regardless of the material used as a liner.”11

Several studies that did not focus on partialcaries removal nevertheless are relevant to thetreatment of deep carious lesions. There has beenevidence for several decades, for example, thatcaries development is arrested in sealed lesions.Handelman and colleagues13-17 have publishedextensively on this subject. Perhaps most fre-quently cited is their 1976 study,13 in which theyplaced sealants on 60 teeth with carious lesionsextending into the dentin; 29 unsealed teethserved as control specimens. They sampled teethfor bacterial culture at periods ranging from oneweek to two years; at the latter point, they founda substantial decrease in the number of cultivablemicroorganisms in sealed lesions when comparedwith the unsealed control teeth. Interestingly,they found the greatest amount of bacterialreduction within two weeks after treatment. In asubsequent study, Handelman’s group,14

describing a radiographic analysis of teethtreated similarly to those in the 1976 study,reported a significant decrease in caries penetra-tion in teeth in which the sealant remainedintact. Bjorndal and colleagues,18 performing step-wise excavation, cultured bacteria from thedentin of 19 teeth after the initial procedure andafter intervals of six to 12 months; at the latterpoint, they observed that CFUs had been reducedsubstantially.




on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

Two randomized controlled trials comparingstepwise and complete excavation, while only tan-gentially relevant to the partial caries removaltechnique, nevertheless are important for resultsrelevant to the risk of pulpal complications aftercomplete removal of deep caries. Magnusson andSundell19 reported postprocedural pulpal compli-cations in eight (15 percent) of 55 teeth treated bystepwise excavation and in 29 (53 percent) of 55teeth treated by direct excavation. Leksell andcolleagues20 similarly reported pulpal exposure in10 (17.5 percent) of 57 teeth treated in stepwisefashion compared with 28 (40.0 percent) of 70teeth treated by direct excavation.

A 2002 study comparing the efficacy of twomaterials used in conjunction with indirect pulpcapping in 48 primary molars reported a successrate, as measured by absence of irreversible pulppathology, of 96 percent for teeth treated with aproprietary adhesive resin system at two yearsafter treatment.21

Al-Zayer and colleagues22 retrospectively ana-lyzed 187 primary posterior teeth (132 patients)treated with indirect pulp capping in which suffi-cient carious dentin was left to preclude pulpalexposure. The authors then followed up patientsclinically and radiographically for periods rangingfrom two weeks to 73 months after treatment. Ofthe 187 teeth in the study, nine (4.8 percent)experienced complications, amounting to a 95 per-cent success rate.

Kreulen and colleagues,23 using a split-mouthmodel, sampled carious dentin from molars beforerestoring the teeth using either a “biologicallyactive” (that is, antimicrobial) resin-modified glassionomer preparation or amalgam. They processedsamples for viable bacteria and evaluated them forcolor and consistency. Dentin from the same sitessimilarly sampled and evaluated at six monthsafter treatment in 39 patients from both groupsexhibited a significant decrease in the meannumber of bacteria and a significant “overalltreatment” effect for color and consistency.

In a microbiological study of dentin samplestaken from 40 carious lesions before and afterundergoing ART, Bonecker and colleagues24 foundsignificant reductions in the frequency and pro-portions of total viable cells as well as of mutansstreptococci (but not lactobacilli) in restorationssealed with a GIC.

Vij and colleagues25 conducted a retrospectiveanalysis of two approaches to treating cariouslesions approaching the pulp in 226 primary

molars (141 patients), including 133 teeth from aprevious study26 that used similar criteria for thesame treatments. The investigators treated allteeth in two stages (not to be confused with step-wise excavation). First, they removed superficialcarious tissue and temporarily filled the cavitywith either zinc oxide–eugenol or GIC. Then, at asecond appointment one to three months later,they either removed the remaining carious tissuecompletely and performed a pulpotomy followedby treatment with formocreosol or removed allbut the deepest layer of remaining carious dentinand performed indirect pulp capping by using oneof two GIC preparations. At three years aftertreatment, the success rate—as measured by theabsence of swelling, abnormal mobility, pain andradiographic signs of pathology—was 94 percentfor teeth treated by means of partial cariesremoval and indirect pulp capping and 70 percentfor the group treated by means of formocreosolpulpotomy. While this study cannot serve to mea-sure the relative merits of partial caries and com-plete caries removal per se, it demonstrates therelative superiority of partial caries removal to atechnique (formocreosol pulpotomy) that someconsider a viable alternative.

DISCUSSION

Is it necessary to remove all carious tissue fromlesions approaching the pulp? Although there issubstantial evidence to the contrary, most practi-tioners continue to follow the basic principleguiding any surgeon: that one must eradicate anyand all affected tissue from the site of an infec-tion. It is not clear, however, whether this prin-ciple is, or ought to be, followed at all times. Inconventional endodontic therapy, for example,which has a high rate of clinical success, it islikely that viable bacteria and necrotic host tissuetypically remain in the root canal system afterinstrumentation and obturation.27

The conventional treatment paradigm has along history. G.V. Black, in his classic 1908 text,asserted that “it is better to expose the pulp of atooth than to leave it covered only with softeneddentine.”28 More recently, the majority of respon-dents to a survey on this subject indicated thatthey would remove all carious tissue even if theprocedure, in their judgment, would risk pulpalexposure; only about one in five respondents saidthey would choose to proceed with partial cariesremoval, and a slightly higher proportion indi-cated that they would initiate or refer the patient




on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

for endodontic treatment.29 In another recentsurvey, conducted in 2006, the majority ofrespondents opted for pulpotomy as the treatmentof choice in a similar scenario. 30

Ironically, G.V. Black also stated that it isimperative that dentists understand thepathology of the caries process lest they bereduced to the role of mechanics.31 It is inter-esting to speculate, given our ability to create arestoration with well-sealed margins and asso-ciated grooves and fissures, what Black would sayabout the subject of partial caries removal today.Several of the studies cited above (such as thoseby Handelman and colleagues,13 Kreulen and col-leagues,23 Maltz and colleagues7-9 and Boneckerand colleagues24) have demonstrated that bacte-rial counts under sealed restorations becomedrastically reduced. In their 2002 study, Maltzand colleagues,7 citing significant decreases incounts of both aerobic and anaerobic viable bac-teria and radiographic evidence of a mineral gainin affected areas, concluded that “completedentinal caries lesion removal is not essential tothe control of caries lesions”—a conclusion thatwas repeated in two follow-up studies.8,9 Kidd,32

who cited most of these same sources and severalothers, including studies of stepwise excavationand partial caries removal, concluded that “thereis no clear evidence that it is deleterious to leaveinfected dentine.”

Some of the best evidence for the rationaleunderlying partial caries removal can be found instudies of a related technique, the stepwise exca-vation approach. The literature regarding step-wise excavation18-20,33,34 has reported consistentlythat residual carious dentin recedes and hardensunder temporary restorations in the interimbetween the initial excavation and reentry. Butas Kidd32 stated, “Why re-enter?” In other words,if the goal is to avoid pulpal exposure andresidual carious dentin poses no threat to thedentition, why subject the patient to a secondexcavation?

Assuming it is preferable to leave caries indeep restorations, must the practitioner alter hisor her restorative technique? The previously citedsurvey of dentists conducted by the PractitionersEngaged in Applied Research and Learning(PEARL), a practice-based research network atthe New York University College of Dentistrysponsored by the National Institutes of Health,29

may hold an answer to that. The survey’srespondents, who represented a wide range of

approaches to restoration, stated that theyexpected that roughly the same percentage oftheir patients would require endodontic treat-ment three to five years after treatment regard-less of whether the respondent favored completeor partial caries removal in deep lesions andregardless of the respondent’s restoration tech-nique. Evidence from the literature also suggeststhat a change of approach is unnecessary. Evenbefore the advent of dentin bonding, the efficacyof bonding to enamel alone was demonstrated in a17-year recall study of a large-particle ultravioletlight–cured resin-based composite in Class I andClass II restorations.35 Moreover, Mertz-Fairhurstand colleagues4 demonstrated that bonding toenamel alone (with carious dentin remaining) wassufficient at 10 years. Dentin bonding adds to ourability to seal restorations, but its long-term effi-cacy is still in question.36

Partial removal of caries from deep lesions usu-ally involves complete removal of carious tissuefrom cavity walls but limited removal from thepulpal floor and axial wall, which are sites ofreduced bond strength. Resin-based compositerestoration polymerization shrinkage can resultin retraction of the bonding agent from the pulpalfloor or axial wall of sound dentin.37,38 Theresulting gap can fill with fluid, and with toothdeformation, the fluid is forced down opendentinal tubules, causing postoperative “occlusalloading sensitivity.” While clinicians may findpulpal floor gaps more often when deep cariesremains because of composite’s inability to bondcompletely to caries-infected and caries-affecteddentin,39-42 the chance of postoperative hypersensi-tivity might be reduced because the pulp is pro-tected from fluid flow in the tubules by the low-permeability zone in deep infected dentin.43,44 Onthe basis of these findings, one might suggestthat infected dentin be removed completely frompreparation walls but selectively from the pulpalfloor or axial wall.

Finally, it is worthwhile to consider the recentmeta-analysis1 that pooled the results of four ofthe randomized controlled trials discussed earlier:those by the Mertz-Fairhurst,2 Ribeiro,5 Mag-nusson19 and Leksell20 research groups. Thereview is entitled “Complete or UltraconservativeRemoval of Decayed Tissue in Unfilled Teeth,”and while one can argue that “ultraconservative”does not apply to the focus of the studies by Mag-nusson and colleagues19 and Leksell and col-leagues20 (stepwise excavation), the authors nev-




on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

ertheless came to the conclusion—tempered bytheir observation that the number of these trialsis small—that “partial caries removal is …preferable to complete caries removal in the deeplesion, in order to reduce the risk of carious expo-sure [of the pulp].”1 Apparently, dentists needmore evidence before they will accept this deter-mination—despite the fact that (to our knowl-edge) no study has been initiated to prove thedesirability of removing all infected dentin. Anobservational study under way within thePEARL practice-based research network willattempt to fill in some of the gaps in our under-standing of deep caries treatment and may pro-vide the basis for a clinical trial.

CONCLUSION

On the basis of the studies cited in this review,one can state that there is substantial evidencethat the removal of all infected dentin in deepcarious lesions is not required for successfulcaries treatment—provided that the restorationcan seal the lesion from the oral environmenteffectively. However, before this concept isaccepted generally by the dental profession, addi-tional clinical trials may be needed. ■

Disclosures. None of the authors reported any disclosures.

The authors acknowledge the support of the National Institute ofDental and Craniofacial Research, National Institutes of Health,through grant U-01-DE016755-01 awarded to the New York Univer-sity College of Dentistry, New York City.

1. Ricketts DN, Kidd EA, Innes N, Clarkson J. Complete or ultracon-servative removal of decayed tissue in unfilled teeth. Cochrane Data-base Syst Rev 2006;3:CD003808.

2. Mertz-Fairhurst EJ, Call-Smith KM, Shuster GS, et al. Clinicalperformance of sealed composite restorations placed over caries com-pared with sealed and unsealed amagam restorations. JADA1987;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. Aclinical, radiographic, and scanning electron microscopic evaluation ofadhesive restorations on carious dentin in primary teeth. QuintessenceInt 1999;30(9):591-599.

6. Foley J, Evans D, Blackwell A. Partial caries removal and cario-static materials in carious primary molar teeth: a randomised con-trolled 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 afterincomplete caries removal. Quintessence Int 2002;33(2):151-159.

8. Oliveira EF, Carminatti G, Fontanella V, Maltz M. The monitoringof deep caries lesions after incomplete dentine caries removal: resultsafter 14-18 months. Clin Oral Investig 2006;10(2):134-139.

9. Maltz M, Oliveira EF, Fontanella V, Carminatti G. Deep carieslesions after incomplete dentine caries removal: 40-month follow-upstudy. Caries Res 2007;41(6):493-496.

10. Fairbourn DR, Charbeneau GT, Loesche WJ. Effect of improvedDycal and IRM on bacteria in deep carious lesions. JADA1980;100(4):547-552.

11. Marchi JJ, de Araujo FB, Froner AM, Straffon LH, Nor JE. Indi-rect pulp capping in the primary dentition: a 4 year follow-up study. JClin 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 ofsealant effect on bacteria in dental caries. JADA 1976;93(5):967-970.

14. Handelman SL, Leverett DH, Solomon ES, Brenner CM. Use ofadhesive sealants over occlusal carious lesions: radiographic evalu-ation. Community Dent Oral Epidemiol 1981;9(6):256-259.

15. Leverett DH, Handelman SL, Brenner CM, Iker HP. Use ofsealants in the prevention and early treatment of carious lesions: costanalysis. JADA 1983;106(1):39-42.

16. Handelman SL, Leverett DH, Espeland M, Curzon J. Retention ofsealants over carious and sound tooth surfaces. Community Dent OralEpidemiol 1987;15(1):1-5.

17. Handelman S. Therapeutic use of sealants for incipient or earlycarious lesions in children and young adults. Proc Finn Dent Soc1991;87(4):463-475.

18. Bjorndal L, Larsen T, Thylstrup A. A clinical and microbiologicalstudy of deep carious lesions during stepwise excavation using longtreatment intervals. Caries Res 1997;31(6):411-417.

19. Magnusson BO, Sundell SO. Stepwise excavation of deep cariouslesions 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 step-wise versus direct complete excavation of deep carious lesions in youngposterior permanent teeth. Endod Dent Traumatol 1996;12(4):192-196.

21. Falster CA, Araujo FB, Straffon LH, Nor JE. Indirect pulp treat-ment: in vivo outcomes of an adhesive resin system vs. calciumhydroxide for protection of the dentin-pulp complex. Pediatr Dent2002;24(3):241-248.

22. Al-Zayer MA, Straffon LH, Feigal RJ, Welch KB. Indirect pulptreatment of primary posterior teeth: a retrospective study. PediatrDent 2003;25(1):29-36.

23. Kreulen CM, de Soet JJ, Weerheijm KL, van Amerongen WE. Invivo cariostatic effect of resin modified glass ionomer cement andamalgam on dentine. Caries Res 1997;31(5):384-389.

24. Bonecker M, Toi C, Cleaton-Jones P. Mutans streptococci and lac-tobacilli in carious dentine before and after Atraumatic RestorativeTreatment. J Dent 2003;31(6):423-428.

25. Vij R, Coll JA, Shelton P, Farooq NS. Caries control and othervariables 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 offormocresol pulpotomy and indirect pulp therapy in the treatment ofdeep dentinal caries in primary teeth. Pediatr Dent 2000;22(4):278-286.

27. Oguntebi BR. Dentine tubule infection and endodontic therapyimplications. Int Endod J 1994;27(4):218-222.

28. Black GV. A Work on Operative Dentistry. Volume 2: The Tech-nical Procedures in Filling Teeth. Chicago: Medico-Dental PublishingCompany; 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. Restorativetreatment decisions for deep proximal carious lesions in primarymolars. Eur Arch Paediatr Dent 2007;8(1):37-42.

31. Black GV. A Work on Operative Dentistry. Volume 1: ThePathology of the Hard Tissues of the Teeth. Chicago: Medico-DentalPublishing Company; 1908.

32. Kidd EA. How “clean” must a cavity be before restoration? CariesRes 2004;38(3):305-313.

33. Bjorndal L, Thylstrup A. A practice-based study on stepwise exca-vation of deep carious lesions in permanent teeth: a 1-year follow-upstudy. Community Dent Oral Epidemiol 1998;26(2):122-128.

34. Bjorndal L, Larsen T. Changes in the cultivable flora in deep car-ious lesions following a stepwise excavation procedure. Caries Res2000;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 compositeClass 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 reviewof the durability of adhesion to tooth tissue: methods and results. JDent 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 polymerizationshrinkage flow in resin composite restorations. Oper Dent2002;27(3):297-304.

38. Lopes GC, Baratieri LN, Monteiro S Jr, Vieira LC. Effect of pos-




on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

terior resin composite placement technique on the resin-dentin inter-face formed in vivo. Quintessence Int 2004;35(2):156-161.

39. Doi J, Itota T, Yoshiyama M, Tay FR, Pashley DH. Bonding toroot caries by a self-etching adhesive system containing MDPB. Am JDent 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 caries-affected dentin. J Adhes Dent 2003;5(1):57-62.

41. Yoshiyama M, Tay FR, Doi J, et al. Bonding of self-etch and total-

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 car-

ious dentin using a polymer instrument without anesthesia versus acarbide bur with anesthesia. JADA 2005;136(5):643-651.

44. Pashley EL, Talman R, Horner JA, Pashley DH. Permeability ofnormal versus carious dentin. Endod Dent Traumatol 1991;7(5):207-211.




on October 20, 2008

jada.ada.orgD

ownloaded from

http://jada.ada.org

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 sup-porting 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 manage-ment, it is not necessary to remove all vestiges of infected dentin from lesions approaching the pulp.

CommentarySince 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 com-mon 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 inju-rious 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 review2 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 understand-ing 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 com-plete 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 cari-ostatic 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 review1 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 mate-rial or resin-modified glass ionomer. The success rates presented at 4 years were 89% and 93%, respectively.

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: [email protected]

www.nature.com/ebd 71

SUMMARY REVIEW/RESTORATIVE DENTISTRY3A| 2C| 2B| 2A| 1B| 1A|

EBD_9-3_71-72.indd 71EBD_9-3_71-72.indd 71 3/10/08 10:25:473/10/08 10:25:47

72 © EBD 2008:9.3

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 fur-ther 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 remov-al 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 par-tial 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 par-tial removal) is generally accepted by the profession additional clini-cal 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

EBD_9-3_71-72.indd 72EBD_9-3_71-72.indd 72 1/10/08 14:49:001/10/08 14:49:00

Documents

Management of the deep carious lesion and the vital pulp dentine complex