Infected Dentine Revisited

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1 Edwin Kidd Ole Fejerskov Bente Nyvd Infected Dentine Revisited Astrct: Dentine ecomes infected s result of cries lesion formtion on root surfces nd when lesions progress following cvittion of enmel lesions. However, this infection is unimportnt ecuse the driving force for lesion formtion nd progression is the overlying iofilm. This explins why root surfce cries cn e controlled y mechnicl plque control nd fluoride, nd restortions re not needed to rrest these lesions. Similrly, the infected dentine in cvitted coronl lesions does not hve to e removed to rrest the lesion. If the lesion is either ccessile or opened for clening y the ptient or prent, the lesion cn e rrested. Seling of infected dentine within the tooth, either y Hll crown in the primry dentition or y prtil cries removl prior to plcing well-seled filling, will lso rrest the lesion. When restoring deep lesions in symptomless, vitl teeth, vigorous excvtion of infected dentine is likely to expose the pulp nd mke root cnl tretment necessry. Thus complete excvtion is not needed nd should e voided. CPD/Clinicl Relevnce: Root surfce cries cn e rrested y clening nd fluoride ppliction. Restortions re not essentil. Vigorous excvtion of softened dentine in deep cvities of symptomless, vitl teeth is contr-indicted. It is not needed nd increses the risk of pulp exposure. Dentl Updte 2015; 42: Cries, the iofilm nd cries control Dentl cries is result of dynmic processes occurring in dentl iofilm. It is chemicl dissolution rought out y metolic ctivity in the microil deposit (iofilm or plque) covering tooth surfce t ny given time. This metolic ctivity results in numerous fluctutions in ph t the interfce etween the iofilm nd tooth surfce. Over time these fluctutions my result in disturnce of the equilirium etween the tooth minerl nd the surroundings. Minerl loss, susequent lesion formtion nd possile cvity formtion in teeth, is symptom of n imlnce in these dynmic processes nd is designted dentl cries. 1 Biofilm formtion nd its metolism is Edwin Kidd, Emerit Professor of Criology, King s College, London, UK, Ole Fejerskov, Professor Emeritus, Fculty of Helth, Arhus University, Denmrk nd Bente Nyvd, Professor of Criology, Fculty of Helth, Arhus University, Denmrk. n uiquitous nturl process; it is prt of hving teeth. However, its possile consequence, lesion formtion nd progression, cn e controlled so tht cliniclly visile lesion never forms or n estlished lesion rrests. The term cries control (rther thn cries prevention) reflects the fct tht iofilm formtion nd metolism cnnot e prevented ut lesion formtion nd progression cn e controlled so tht lesions never ecome visile or estlished lesions rrest. Control of the iofilm is the tretment of cries. 2 The most importnt control mesures re to clen teeth regulrly, nd thus distur the iofilm mechniclly, with fluoridecontining toothpste nd regulte sugr intke. Lesions, whether in enmel or dentine, surfce intct or cvitted, cn e rrested y iofilm control lone provided the lesion cn e ccessed for clening. Where cvitted lesion is not ccessile, filling my e required. However, insertion of fillings without reinforcement of plque control is mlprctice. Fillings do not tret cries; they merely serve to hide the symptom. Fillings cnnot prevent further cries ttck nd plcing them, without ddressing the cuse of lesion formtion in the first plce, is wste of time nd money. It is tntmount to repiring fire dmged uilding efore putting out the flmes. Is cries n infectious disese? Although cries is cused y the cteri in the iofilm it is not n infectious disese in clssicl sense. The dentl iofilm consists of commensl orgnisms, not extrneous infecting invders. Cries lesions re the result of ecologicl disturnces to the iofilm community. These disturnces originte in the metolic ctivity of the host s own Figure 1. This lesion is ccessile to clening nd cn e rrested. Opertive intervention is contrindicted. 802 DentlUpdte Novemer 2015

2 Figure 2. Four consecutive micro-computed tomogrphy scns through deep cries lesion in 2000-yer-old tooth from Imperil Rome. The lesion hd penetrted into the pulp where tertiry dentine is indicted with n sterisk (). Note the very pronounced trnslucent dentine rections (tuulr minerliztion) tht delinete the se of the dentine cries cvity indicted y rrows on (), (c) nd (d). The frmed re in () shows n erly cries lesion through enmel with dentine deminerliztion t the enmel-dentine order. microflor in response to vrious externl fctors. Orl cteri re ultimte dptors nd survivors to the situtions they find themselves in! Two exmples of dpttion of the iofilm of gret relevnce to cries re n overgrowth of ciduric cteri in response to incresed sugr exposure or decresed slivry flow. This dpttion to the prolem in hnd is clled the ecologicl plque hypothesis. 3 This not only explins why cries lesions develop, it lso explins why some ptients my not develop lesions despite tooth surfces eing constntly covered y iofilm. When cries develops it is therefore logicl to focus on strtegies to restore the ecologicl lnce y mesures such s mechnicl plque removl nd sugr control. 3 This pper will now concentrte on crious dentine when the enmel over it is cvitted or the dentine hs no enmel cover, s in root surfce. This dentine is infected ut, s will emerge, this infection is reltively unimportnt. By infected we men tht the dentine contins microorgnisms. The cries process is driven y the iofilm nd control of the overlying iofilm is much more importnt thn deling with the infected dentine. It is time to ly few ghosts, such s excvting nd restoring teeth to remove infected dentine! But efore this we need to tke rief detour to cover some relevnt pthology. Some pthologicl considertions The following re importnt to the rgument: 4,5 Dentine lesions eneth deminerlized, ut uncvitted, enmel re result of the iofilm metolism on the tooth surfce. The surfce is ccessile to clening nd this is why these lesions cn e rrested. They never justify opertive intervention (Figure 1). The dentine is not infected. Once cvity forms lesion development is likely to progress s result of cteril metolism. Micro-orgnisms invde the exposed dentinl tuules. This dentine is infected. Softening (deminerliztion) of the dentine often precedes the orgnisms responsile for it. It hs een suggested tht the dentist should remove infected dentine nd leve ffected dentine which is cple of reminerliztion. However, infected nd ffected dentine re histologicl concepts nd the dentist cnnot know for sure where they re in the lesion when deling with it cliniclly. Dentine is vitl tissue contining odontolst processes nd dentine nd pulp must e considered together. Dentine mounts cellulr, driven defence to the metolic processes in the iofilm, resulting in zone of tuulr minerliztion the so-clled trnslucent zone. In histologicl sections this zone ppers trnslucent ecuse the minerl in the tuules mkes the tissue more homogeneous. This zone hs sometimes een termed sclerotic ut this terminology is unfortunte ecuse dictionries define sclerotic s ecoming rigid nd unresponsive; losing the ility to dpt, ut this is not relly wht is hppening. Minerl is lid down within nd round the tuules nd the most relevnt consequence of this is the permeility of the dentine is reduced. In ddition, tertiry dentine my form t the pulp-dentine order (Figure 2) nd this lso reduces the permeility of the dentine. In slowly progressing lesions, these odontolstic rections grdully occlude the tuules nd sel off the pthwys etween the orl environment nd the pulp. This is cute iologicl defence mechnism. In rpidly progressing dentine lesions, the odontolsts my e destroyed nd this results in open tuulr pthwys in the dentine. These tuules my therefore e ccessed y cteri. When cteril invsion penetrtes the tertiry dentine there will eventully e severely inflmed pulp followed y necrosis. It is this pulpo-dentinl complex, with certin defence nd inflmmtory rections, which the clinicin interferes with when instituting opertive tretment. It is unfortunte tht the clinicin cnnot see the histologicl chnges of infected dentine, ffected dentine, tuulr minerliztion, tertiry dentine, pulpl inflmmtion, destruction of odontolsts nd pulpl necrosis. The clinicin cnnot know when excvting the depth of dentine tht remins, how close the excvtor is to exposure. To mke mtters worse, clinicl symptoms relte poorly to pulp pthology nd this is prticulrly unfortunte ecuse the clinicin needs to ssess whether the pulp is likely to survive. Clinicins use the terms reversile nd irreversile pulpitis to predict whether pulp is likely to survive or Novemer 2015 DentlUpdte 803

3 whether its removl is inevitle. In reversile pulpitis the pin evoked y hot, cold or sweet stimulus is of short durtion, disppering when the stimulus is removed. The clinicin hopes to preserve helthy, vitl pulp. In irreversile pulpitis the pin persists for while fter removl of the stimulus, or pin occurs spontneously, nd the pulp is likely to e so dmged tht it must e removed. The clinicin uses vitlity test (rection to hot, cold or electricl stimuli) to judge totl pulp necrosis nd it is extrordinry tht this works t ll ecuse these tests stimulte nerves wheres vitlity depends on lood supply! In other words, the vitlity test is surrogte mrker; when nerves re gone, lood vessels re s well. It is remrkle tht, tken together, these clinicl mrkers work rther well; symptomless, vitl pulp cn usully e sved provided the dentist is not osessed with removing infected dentine y cutting innumerle tuules of trnslucent dentine wy nd exposing the vitl odontolsts of sound dentine. We will now consider two circumstnces where infected dentine is present. These re root cries nd dentine cries in cvitted lesions. Infected dentine in root cries 2 Figure 3 ( d) is rther well known illustrtion tht hs een reproduced in mny textooks nd rticles. The four pictures show root cries lesion in n upper cnine. In Figure 3 the lesion is ctive, it is soft nd the dentine would e infected if it were to e smpled for culturing. Despite this infection, the lesion is driven y the iofilm t the tooth surfce, not the infected dentine, nd mechniclly disturing the iofilm regulrly with fluoride-contining toothpste nd fluoride ppliction is the tretment required to trnsform the lesion from n ctive lesion to n rrested one. Over the months the soft surfce is grdully worn wy nd the surfce ecomes hrd due to minerl uptke in the surfce lyer, nd it picks up stin. This is why it now looks drk rown (Figure 3d). Note this mngement puts the control where it hs to e with the ptient. c d Figure 3. ( d) Consecutive stges of non-opertive tretment of ctive non-cvitted root surfce cries lesion on the uccl surfce of upper left cnine. The figure shows chnges in the clinicl ppernce of the lesion fter 3, 6 nd 18 months. Note tht, within the oservtion period, improved orl hygiene leds to grdul chnges in colour nd surfce structure of the lesion, from soft nd yellowish to hrd nd drkly discoloured. Note lso chnges in the topogrphy of the mrginl gingiv. Figure 4. () Root cries lesions uccl to upper premolrs with previous tooth-coloured restortions sitting within new cries lesions. () Disclosing shows hevy iofilm deposits over the ctive lesions. To tret these lesions restortively would e ridiculous! 804 DentlUpdte Novemer 2015

4 Would the lesion in Figure 3d yield microorgnisms if cultured? Certinly some, ut they re of no consequence. Contrst this to the lesion seen in Figure 4 nd. Here we see n ctive root cries lesion in premolr nd dentist hs plced restortion some time previously, to no effect t ll, s new cries hs developed round the lesion nd, when disclosing solution is used, the surfce of the lesion looks like culture plte. Finlly, consider the lesions in Figure 5 ( c). Initilly, dentist nd ptient hve concentrted on iofilm control. The incisl enmel hs een trimmed to id ccess for the rush, ut then the ptient is put in chrge nd, in Figure 5, lesions re rresting. But how ugly they re! It is wonderful tht we now hve such eutiful restortive mterils nd dhesive techniques to improve ppernce, ut ewre! It is tempting for the ptient to elieve tht the dentist hs solved the prolem y filling the teeth (Figure 5c). Although the dentist hs produced eutiful restortions, the rel tretment is the iofilm control y the ptient, nd the fct tht the dentine ws infected is totlly irrelevnt! Infected dentine in deep coronl lesions 6 Figure 6 shows deciduous tooth where there is n ctive, cvitted lesion tht cnnot e clened. Something needs to e done to fcilitte clening nd, in this instnce, the dentist, fter discussion with the prent, hs elected to open the lesion for clening. This is rpidly done with ur nd no locl nesthetic is required. Now the prent is shown his/her essentil role in cries control, which is dily removl of the iofilm with fluoride-contining toothpste. The finl picture tken 6 months lter (Figure 6) shows the lesion rrested nd, provided the clening continues, this tooth should go symptomless to exfolition. But the most importnt prt of this mngement is the ctive role of the prent. This technique ws clled nonrestortive cvity tretment nd it is funded on the Helth Service in Hollnd. Note in this cse tht infected dentine ws present ut, just s in the root cries lesion (Figure 3), rushing hs grdully removed the soft dentine nd the c Figure 5. () Cervicl lesions covered y plque. () Sme cvities fter removing overhnging enmel with dimond finishing ur nd instruction in clening. Teeth were rushed twice dy with toothrush nd toothpste with fluoride. From criologicl point of view these teeth re now stle, ut to improve their ppernce they re to e restored with composite. (c) Completed restortions the smll colour difference is due to the teeth eing dry nd will dispper fter some hours when they re wet with sliv. surfce of the lesion is now hrd, shiny nd coloured rown. The infected dentine ws not immeditely removed nd this hs hd no detrimentl consequence. In fct, this is exctly the sme pproch s is used in the non-opertive tretment of ctive noncvitted lesions nd perhps it would e more pproprite to cll it non-opertive cvity tretment. Figure 7 ( c) shows n lterntive mngement for such lesions in deciduous teeth, the Hll crown. These crowns rek ll the conventionl rules in tht no cries is removed. An pproprite Figure 6. Non-restortive cvity tretment (NRCT). (Courtesy of Rene Gruythysen nd BSL, Springer Medi, Houten, the Netherlnds.) () Cries in upper deciduous molrs efore using ur to slice nd open the teeth for clening. () Upper deciduous molrs 6 months fter NRCT. The cries lesions re rrested. size of stinless steel crown is selected nd cemented onto the crious tooth with no preprtion nd no locl nesthetic required. No infected dentine is removed, indeed, it is seled in the tooth, nd leving infected dentine is of no consequence. Clinicl trils crried out in generl prctice showed these crowns were more successful thn glss ionomer restortions with conventionl dentine cries removl nd Novemer 2015 DentlUpdte 805

5 the little ptients preferred the crown technique to the intrcoronl restortion. In Figures 8 nd 9 there re lrge occlusl lesions in permnent teeth. In Figure 8 there is cvity ut there is lso overhnging enmel nd the iofilm on the dentine surfce is lrgely protected from disturnce y the toothrush. The lesion is ctively progressing nd clening lone will not solve this prolem; restortion is required to id iofilm control nd restore the tooth. Just s in the deciduous dentition, opening the lesion to llow clening would lso led to lesion rrest. In Figure 9, the lesion ws originlly ctive nd of similr size ut overhnging enmel hs frctured wy nd this lesion is now clensle. It is now rrested, clen, hrd nd stined. Figure 10 is rdiogrph of the deep clinicl lesion in Figure 8. The lesion is pproching the pulp ut this tooth is symptomless nd vitl nd there is every chnce tht the pulp cn e preserved. In pst yers the restortive pproch would hve een to excvte the soft dentine thoroughly prior to tooth restortion, the im eing to remove ll the infected dentine. However, this complete excvtion would e very unwise nd would prejudice the pulp s it might expose the pulp nd require root cnl tretment. As we hve lredy seen, the infected dentine is of no clinicl consequence s fr s rresting the lesion is concerned nd thus complete excvtion seems creless to the point of eing unethicl. A sensile pulp-protecting technique prctised for mny yers is clled indirect pulp cpping, where tiny mount of soft dentine is left over the pulp to void exposure. The difficulty is to know where to stop excvtion s the distnce to the pulp is unknown. Perhps much more deminerlized soft dentine could e left without compromising pulp vitlity, so clled prtil cries removl. A numer of rndomized clinicl trils, on oth deciduous nd permnent teeth, hve compred prtil nd complete cries removl in deep dentinl lesions in symptomless, vitl teeth. 5 By deep dentinl lesion the opertor considers the pulp my e exposed y prolonged excvtion. Some 20 50% of completely excvted deep dentinl lesions re likely to experience pulp exposure, while hrdly ny of those with prtil cries removl show exposure. c Figure 7. The Hll crown. () Before cementtion; no cries removl nd no occlusl or proximl reduction. () The crown directly fter cementtion. Inevitly the ite is high. (c) Six weeks lter. The ite hs nerly re-estlished. Some of these studies hve used the so-clled stepwise excvtion technique in the prtil cries removl group. In this technique, fter prtil removl of infected dentine corresponding to the deepest prt of the lesion, lesions with clen mrgins re seled nd then re-opened fter Figure 8. Active cries lesion with lrge cvity extending deep into dentine. (Permission from George Thieme Pulishers.) Figure 9. Arrested occlusl cries lesion. The prtly undermined enmel mrgins hve een frctured nd rded wy y mstiction. The iofilm in the cvity is removed ecuse the tooth is in functionl occlusion. The drk rown dentine is hrd nd pinless. Figure 10. Rdiogrph of the deep occlusl cries lesion seen cliniclly in Figure 8. (Permission from George Thieme Pulishers.) numer of weeks or months. Excvtion is then continued until hrd/firm dentine is reched. The logic of this iologicl pproch is to rrest lesion progression y depriving cteri of nutrients nd llowing time for the defence rections of tuulr minerliztion nd tertiry dentine 806 DentlUpdte Novemer 2015

6 Figure 11. () Clinicl picture of prtil excvtion of deep lesion. The dentine is soft nd wet. The tooth is now restored to give good cvity sel. () After few months the tooth is reopened. Notice tht the dentine is now drk rown nd no longer wet. When scrped with n excvtor, this dentine is hrd ut the surfce cn e removed provided the dentist uses shrp excvtor firmly. This lesion is seen cliniclly in Figure 8 nd rdiogrphiclly in Figure 10. (Permission from George Thieme Pulishers.) formtion efore completing excvtion. These studies hve yielded some fscinting results: On re-entry, the dentine hs totlly chnged. Where there ws oozing moisture, soft nd ple yellow dentine prior to the first restortion, it is now hrd ut sometimes crumly, dry nd drk rown in colour (Figure 11, ). Re-entry to complete excvtion exposed the pulp in some 8 17% of the teeth nd, since these teeth were symptomless nd vitl prior to re-entry, one wonders if this second excvtion ws either necessry or wise. In mny studies, the infected dentine ws smpled efore the first restortion nd then gin on re-entry. The microiology ws drmticlly chnged. There were fewer microorgnisms nd those tht remined did not elong to the highly ciduric flor. This is exctly wht would e predicted ccording to the ecologicl plque hypothesis. Seling the cvity hs chnged the environment. The defence mechnisms of tuulr minerliztion nd tertiry dentine hve reduced the permeility of the dentine. The micro-orgnisms re now stressed, cut off from the mouth y the sel of the restortion nd lso cut off from nutrients coming up through the dentinl tuules y the defence rections. The strved micro-orgnisms dpt to the new environment. Wht should we excvte nd how? From the discussion ove the nswer my e nothing (non-opertive cvity tretment, Hll crown) or prtil cries removl. In deep dentinl lesion nd symptomless, vitl tooth the excvtion should never im to scrpe hrd squeky dentine; this so-clled complete cries removl invites pulp exposure. When restoring tooth with conventionl filling, the clinicl ims of excvtion should e: Avoid exposure. Do not ttempt to excvte to hrd tissue in deep dentine lesions. There is no need to remove ll of the infected dentine prior to plcing the restortion. You do not know where the pulp is nd there is no need to risk exposure. Alwys produce sound cvity mrgin for onding. Cvity sel is very importnt to pulpl helth nd microiologicl control. Use hnd excvtor rther thn conventionl ur close to the pulp! Tctile feel is difficult when using ur, even t low speed. Excvtion is conveniently crried out with excvtors, lthough some dentists use round cron steel or tungsten-cride urs t low speed. Some smrt techniques hve een designed to remove only infected dentine, leving ffected dentine ehind. 7 These include the use of plstic urs, nd fluoresce-ided cries excvtion (FACE) techniques, sono-rsion nd ir rsion. However, since the level of infection is irrelevnt, these re not required. Cries disclosing dyes re notoriously contr-indicted. Originlly designed to stin infected dentine, they encourge overcutting of tissue tht should not e removed. Chemo-mechnicl excvtion techniques using either sodium hypochlorite-sed or pepsin-sed gents, used with instruments gently to rde the cvity floor, were designed to dissolve dentured collgen selectively, removing hevily infected dentine t the se of the cvity. These techniques re very gentle s fr s the ptient is concerned. There is no virtion s with conventionl ur nd no feeling of pressure s is felt when n excvtor is used. For those dentists treting very nervous ptients, these methods my still e helpful, even when removing less dentine thn ws originlly intended. Conclusions Dentine ecomes infected with commensl micro-orgnisms s result of cries lesion formtion on root surfces nd when lesions progress following cvittion of enmel lesions. However, this infection is unimportnt ecuse the driving force for lesion development nd progression is the overlying iofilm. This explins why root surfce cries cn e controlled y mechnicl plque control using fluoride toothpste, nd restortions re not needed to rrest these lesions. Similrly, the infected dentine in cvitted enmel lesions does not hve to e removed to rrest the lesion. If the lesion is either opened for clening y the ptient or prent, the lesion cn e rrested. Seling of infected dentine within the tooth, either y Hll crown or 808 DentlUpdte Novemer 2015

7 y prtil cries removl prior to plcing well-seled filling, will lso rrest the lesion. When restoring deep lesions in symptomless, vitl teeth, vigorous excvtion of infected dentine is likely to expose the pulp nd mke root cnl tretment necessry. This complete excvtion is not needed nd should e voided. Acknowledgements Figures 1, 2, 3, 5, 7, 9 re reproduced from: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, The dentist who took ech clinicl photogrph nd cred for the ptient is cknowledged y signture on the picture. This cknowledgement is importnt ecuse illustrtions of this qulity re difficult to produce ut invlule teching mteril. Further reding 1. Fejerskov O, Nyvd B, Kidd EAM. Dentl Cries: Wht is it? In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, 2015: pp Nyvd B, Fejerskov O. The cries control concept. In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, 2015: pp Mrsh PD, Tkhshi N, Nyvd B. Biofilms in cries development. In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, 2015: pp Fejerskov O. Pthology of dentl cries. In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, 2015: pp Kidd EAM, Bjorndl L, Fejerskov O. Cries removl nd the pulpodentinl complex. In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/Blckwell, 2015: pp Kidd EAM, Frencken J, Nyvd B, Splieth C, Opdm N. Clssicl restortive or the minimlly invsive concept? In: Dentl Cries. The Disese nd its Clinicl Mngement 3rd edn. Fejerskov O, Nyvd B nd Kidd EAM (eds). Oxford: Wiley/ Blckwell, 2015: pp Almeid Neves A de, Coutinho E, Crdoso MV, Lmrechts P, vn Meereek B. Current concepts nd techniques for cries excvtion nd dhesion to residul dentin. J Adhes Dent 2011; 13: FOR THE TREATMENT OF PERIODONTITIS AND PERI-IMPLANT MUCOSITIS CHLO-SITE CLOSES THE SITE STOPS THE INFECTION RESTORES POCKET HEALTH FREE TESTER SYRINGE WITH YOUR FIRST ORDER Receive free 0.25ml syringe with your first order of ChloSite. Pck sizes: 6 x 0.25ml & 4 x 1.0 ml. Offer suject to vilility One in three of your ptients over 40 will hve perio-disese, nd with the increse in populrity of dentl implnts there is lso the potentil for more peri-implnt disese. Inhiits the growth of orl pthogens responsile for periodontitis nd peri-implnt mucositis Allows nturl heling nd regenertive processes to tke plce Esy to pply nd well tolerted y ptients Use s n djunct to root plning References ville on sles@swllowdentl.co.uk Novemer 2015 DentlUpdte 809