154 D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–1611. Introduction investigators estimated from a separate histologic evalua- tion that 75% of the teeth selected for indirect pulp therapy This article will review current modalities for the treat- would have been exposed if all carious dentine werement of pulps of primary and young permanent teeth and removed. Despite the advanced state of the disease in thedescribe new and exciting therapies that might supplant majority of these teeth, only 3% of 475 teeth treated indir-them in the future. Over the years, pulp treatment of primary ectly exhibited frank clinical failure. Unfortunately, thisand young permanent teeth have become so dissimilar that seminal study was reported only in abstract form andtheir descriptions are rigidly delimited in textbooks and never published in a peer-reviewed journal. However, itreview articles. Classically, for example, a pulpotomy in a does suggest that clinicians should not so aggressivelyyoung permanent tooth is undertaken to promote apexogen- leap from deep caries removal into pulpotomy therapy.esis; under these conditions, retention of the vitality of the Perhaps a bias toward removing all unsound dentine artiﬁ-radicular pulp is imperative. In contrast, the pulpotomized cially expands the number of primary teeth that dailyprimary tooth is commonly treated with formocresol (FC), a receive more involved treatment. In this vein, Coll andcaustic formulation that kills tissues. However, innovations Foaoq  recently urged that the use of indirect pulp ther-in materials and advances in biology suggest that there may apy in primary teeth be expanded.soon be a convergence of therapies for teeth of either denti-tion needing pulp treatment. For this reason, we will depart 2.2. The futurefrom tradition and add some thoughts about young perma-nent teeth to our discussion of pulp therapy for primary Research has demonstrated that the capping agent used inteeth. an indirect pulp treatment is immaterial as long as it seals the carious dentine from oral ﬂuids . This mode of ther- apy is essentially passive. Provided the inﬂammation is not2. Indirect pulp therapy too severe, nutrient deprivation inhibits further bacterial metabolism and the pulp is able to recover. Unfortunately, Giving a pulp the opportunity to recover from the toxins no therapy exists for more advanced disease states.of dental caries by judiciously removing infected dentine Dentistry needs a way to actively treat carious dentine inand isolating the remaining carious lesion from oral ﬂuids situ. We suggest that the direct treatment of diseased dentinewith a restorative material is now an accepted treatment for with agents that neutralize toxins, stiﬂe microbes andbadly decayed primary and permanent teeth [1,2]. Clinical mollify pulp inﬂammation is an objective second only tostudies have shown that when a pulp is “affected”, but not decay prevention in worthiness. To be able to arrest pulp“infected”, the resultant pulpitis can be reversed . pathology without reverting to pulp removal supercedes allAnother positive response is the deposition of secondary of the other modalities we will discuss in this article.or reparative dentine beneath the affected zone . Leksell Although Massler felt in 1958  that sterilization of deepet al.  have determined that a slower, “stepwise” excava- carious dentine as an alternative to pulp exposure was nearlytion protocol in deeply carious permanent teeth resulted in realized, events since have not proved him prophetic. Wesigniﬁcantly fewer pulp exposures. hope that researchers in the 21st century will address the Indirect pulp therapy in primary teeth is probably less most important shortcoming of dentistry—our inability tocommon than in permanent teeth. There are probably promote healing of the infected pulp.several reasons for this. First, pulp exposure resultingfrom aggressive dentine removal is easier to resolve inprimary teeth; a pulpotomy treatment in a primary tooth is 3. Direct pulp cappingless complex and costly than root canal therapy in a perma-nent tooth. Secondly, the thinner dentine layer in primary Direct pulp capping of teeth exposed during cariesteeth necessitates a higher degree of clinical judgement removal has not been viewed as mainstream treatment forabout the thickness of the remaining carious dentine and either primary or permanent teeth . Stanley and Cox arehow closely it approximates the pulp. And thirdly, behavior at the forefront of a movement to disprove the axiom “themanagement considerations perhaps tilt the choice to some- exposed pulp is a doomed organ”. They wish us to considerthing perceived to be deﬁnitive, like a pulpotomy, rather pulp as a tissue with many more regenerative powers thanthan the uncertainty of an ambitious indirect pulp cap. has been traditionally held.2.1. The past 3.1. The past The pulps of primary teeth have been shown to be quite The introduction of inorganic calcium hydroxide (CH) toresilient, and the few studies that have weighed the recovery dentistry spawned a biologic revolution . Because CHof indirectly treated primary teeth have been encouraging. can elicit dentine bridge formation when applied to pulpThe most comprehensive evaluation was carried out at the tissue, pulp capping as a modality became feasible. At theEastman Dental Center in the early 1960s . The same time, the very properties of CH, which provoke
D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–161 155healing, can also elicit untoward reactions . Attitudes of meant that less of the pulp was encroached upon by newclinicians in response to these side effects, justiﬁed or not, dentine. These investigators found no evidence of internalhave stalled the acceptance of CH as a universal inductor of resorption within the study period of 63 days. In our estima-reparative bridge formation. This is particularly true as it tion, the use of CH cements on non-inﬂamed primary pulpsapplies to pulp capping in primary teeth. is an acceptable treatment. When pulps of primary teeth are minutely exposed during For those willing to try CH cements on cariously exposedcaries removal—or even when they are exposed iatrogeni- primary teeth, the prospects for success would probablycally or by trauma—most dentist opt for a pulpotomy. The beneﬁt from the following protocol: more extensive debri-reluctance to cap the pulp with CH under any circumstance dement and absolute hemostasis. The latter might beis the fear that it will promote internal resorption. While it is prompted with the use of an astringent, as recommendedtrue that CH pulpotomy has fallen from favor because of the by Stanley . The former might be obtained with sodiumhigh incidence of internal resorption , there is no hypochlorite as an irrigant (as suggested by Cox for totalevidence, of which we are aware, that demonstrates that etch bonding pulp treatment ) or by frank tissue excisionthe application of CH to coronal pulp will automatically (as suggested by Cvek  for the treatment of traumaticelicit a similar response. It is our opinion that many primary pulp exposures). Mechanical removal of infected tissue mayteeth are needlessly pulpotomized because of a generaliza- be the only means currently at our disposal, since results oftion. attempts [17,18] to quell experimental pulp inﬂammation, There are two conditions that might favor internal resorp- while provocative, have not been deﬁnitive.tion in pulpotomies but not in pulp caps: geometry andinﬂammation. First, the ratio of surface area of tissue in 3.2.2. Direct bondingcontact with CH relative to the remaining tissue volume is Recent advances in total etch direct bonding have evokedconsiderably higher in the case of a pulpotomy than in a an interest in applications for pulp therapy. The key compo-pulp capping. If, by itself, CH can elicit side effects, it is nent of the system is the multipurpose dentine bondingmore likely to do it in narrow pulp canals. Second, pulpo- adhesive, which, when it inﬁltrates into acid etched dentine,tomies are performed on carious teeth with inﬂamed pulps, forms an impermeable hybrid layer. Several groups havewhereas, in pulp capping, this may not be the situation. The investigated the responses of non-exposed and exposednegative actions of CH may reﬂect as much its inability to pulp to dentine bonding systems and have proposed themquell inﬂammation, as its ability to stimulate on its own. for pulp capping [15,19,20]. Based on preliminary ﬁndings, This thesis seems to be borne out by the ﬁndings of Kopel  strongly advocated their adoption as cappingSawusch . In a pulp capping study using inorganic CH agents for primary teeth.and Dycal he reported a failure rate of 13% and 7%, respec- The attractiveness of these systems is that a polymerictively, in teeth where radiographic evidence indicated ques- ﬁlm can be layered over an exposure site without displacingtionable carious exposures, but a failure rate of 29% and pulp tissue and onto surrounding dentine where it permeates41% when teeth were classiﬁed as deﬁnitely exposed. Prior the tubules. Furthermore, these adhesives are hydrophilic,to capping, the exposure was debrided with either saline or meaning that dentine and pulp need not be dehydrated prioreugenol. We conclude from this and other studies that extant to their application. The adhesive ﬁlm is cured by light, andinﬂammation ampliﬁes CH failures, and until it can be then acts as a barrier as a composite resin is gently spreadmoderated, direct pulp capping of primary teeth with CH over the pulp onto the surrounding dentine. After theshould be restricted to mechanical exposures. composite resin is cured, the exposure is sealed against microleakage.3.2. The future Provided dentine adhesives exhibit favorable biologic properties, the advantages of this system are obvious.3.2.1. Calcium hydroxide First, the primer and dentine adhesive work in a wet envir- CH may have a rebirth in the form of hard-setting or light onment, a property that must surely reduce the potential forcured products. According to Stanley , inorganic CH, dehydration injury. And secondly, these hydrophilic adhe-with its very basic pH, creates zones of obliteration and sives apparently ﬂow well over the wet pulp and form acoagulation necrosis superﬁcial to the deeper zones where continuous seal onto the dentine. And thirdly, this prelimin-reparative dentine ultimately begins. Thus in the process of ary covering helps prevent the displacement of compositeinitiating repair, CH injures the pulp. The lower pH CH into the pulp chamber. However, despite these theoreticalproducts such as Dycal may avoid major tissue damage attributes, solid evidence is necessary before they can beand stimulate reparative dentine more directly. In studies recommended as pulp capping agents. As a prerequisite,on non-inﬂamed primary canines, Turner et al  found the dental adhesive, or the primer, must not be cytotoxic;that pulps directly capped with inorganic CH differed from at a minimum, they must be at least neutral with respect tothose treated with hard-setting products by the amount of living cells. And as a bonus, the formulation should benecrosis and thickness of the dentine bridge. The cements antimicrobial and have an ability to stimulate reparativewere less injurious and their bridges were thinner. This dentine like CH.
156 D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–161 Whether dentine adhesives are toxic, neutral or inductive results are encouraging, it must be emphasized that theseof reparative dentine is important in the light of previous studies were relatively short-term.ﬁndings. Several investigators have theorized that pulp irri- Findings from histologic studies in primates have gener-tation following placement of a restoration is most often the ated controversy [15,29–32], while those in humans haveresult of marginal microleakage [22,23] and not the materi- revealed some signiﬁcant deﬁcits [33–35].als per se. Substantiating these earlier conclusions, Cox et In the majority of studies with primates, exposed pulpsal.  have demonstrated that pulps of primates exposed capped using the total etch procedure and dentine bondingdirectly to a variety of restorative materials respond favor- agents underwent a typical healing cascade which culmi-ably, provided that there is no microleakage. Furthermore, nated in some degree of dentine deposition [15,29–31,36].silica cement, zinc phosphate cement, a hard-setting CH However, one study reported disastrous results with thesecement and a composite, all initiated dentine bridging. agents, and the authors stated ﬂatly that their use in vitalOnly amalgam failed to stimulate reparative dentine, pulp capping is contraindicated . Unfortunately, thealthough inﬂammation abated with time. These investiga- same protocols and materials were not used in all studies,tors concluded that pulp responds favorably to capping with so that any sweeping conclusion about the state of the art isany number of materials, provided bacterial contamination far too premature.is prevented. They also speculated that some degree of irri- Histologic studies of human teeth capped directly withtation is necessary to incite dentine formation, something dentine bonding agents suggest that they possess less recup-that amalgam did not provide. The failure of dentine adhe- erative powers than those of primates. Mechanicallysive to stimulate dentine would not necessarily rule it out as exposed primary teeth demonstrated microabscesses adja-a capping agent, but one might question the long-term cent to the exposure site, with no dentine bridging in anycompatibility of pulp cells against an artiﬁcial surface. specimens . Pulps of sound premolars, exposed and Because acid in some form is used in dentine adhesive capped with an adhesive system, exhibited a persistentsystems to remove the smear layer and open dentine tubules, mild inﬂammation and no evidence of repair after severalpulp tissue must tolerate an acidic environment in order for months . In another study on sound premolars, resindirect capping to succeed. Snuggs et al.  have provided particulates were observed in the pulp . They appearedevidence to suggest that pulp does indeed have a high toler- to have triggered a foreign body response and preventedance for acidic conditions. When monkey teeth were calciﬁc bridge formation. Inokoshi et al.  found chronicdirectly capped with silicate or zinc phosphate cements ulcerative pulpitis in the teeth they capped. In contrast,and sealed with ZOE to exclude bacteria, an inherent heal- Katoh  found pulp irritation to be minimal, withing capacity of cell reorganization and dentineal bridging evidence of dentine bridging in 95% of cases.was observed. The discrepancies between species and laboratories may An overall statement about the antibacterial properties of be related to protocols, materials or both. Cox, who reportsdentine adhesives is impossible at this time. The current favorable results in primates, contends that hemostasis is theproducts variably use cleaners, primers, sealers and etchants crucial step, and that it is obtained best with sodium hypo-preparatory to adhesives. Any or all could be antibacterial. chlorite (NaOCl) . This solution dissolves tissue and hasHowever, an in vitro study by Emilson and Bergenholtz  been evaluated as an agent for pulp amputation [38–40].found that antibacterial properties were exhibited only by Therefore, its attributes, other than hemorrhage control,cleaners, primers and etchants. Of the four systems they may be its ability to purge bacteria, superﬁcial inﬂamedevaluated, none of the cured adhesives demonstrated anti- tissue and dentine debris from the exposure site.bacterial effects. This study suggests that the antibacterial Recently, reports for several studies have beenproperties of dentine adhesives will be short-term, unless controversial, with some showing severe responses ,efforts are made to incorporate releasable antibacterials. others reporting minimal to moderate reactions , while Some of the biologic properties of dentine adhesives are others observed excellent results including dentine bridgecurrently being examined in vivo. From preliminary animal after etching and covering the pulp with dentine adhesivesand human studies evaluated by clinical criteria, the accep- [43–46]. Another study reported that capping the pulp withtance of direct bonding by the pulp has been encouraging. a polyacid-modiﬁed resin-based composite (compomer)Unfortunately, the histologic response of pulp to these mate- also produced satisfactory pulpal response . From arials is less clear-cut. clinical and radiographic standpoint, dentine adhesives Clinical studies on the use of dental adhesives as direct used as a direct pulp capping material have also beenpulp capping agents in human permanent [20,27] and reported as successful .primary teeth  have demonstrated short-term success. Because of these controversial results, at present weHeitmann and Unterbrink  reported no symptoms in cannot recommend dentine adhesives for direct pulpall eight teeth they treated; Kashiwada and Takagi  capping until more favorable human studies have beenhad four failures out of 64 direct capping procedures; and reported. One of the shortcomings of current testing inAraujo et al  observed no adverse clinical or radio- monkeys and humans is the shotgun approach to testinggraphic ﬁndings in 15 primary molars. While the overall products. Because components and protocols are so
D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–161 157different, negative ﬁndings do not necessarily condemn clotting, the internal resorption of primary teeth was stilldental adhesives in general as direct capping agents. Before observed .more clinical trials are undertaken, we suggest that the most In an attempt to minimize the cutting of major pulpbiologically acceptable dental materials and ancillary agents vessels and resultant blood clots, Schroeder et al. be determined ﬁrst in vitro. As a step in that direction, a performed partial pulptomies on primary teeth. Internalrecent study determined that the components of three one- resorption was apparently reduced, but the overall successbottle adhesive systems were highly cytopathic to an odon- rate was only about 80%. This rate of success is certainly notoblast cell line . Such assays can eliminate less promis- better than that reported for FC, and the procedure is moreing candidates, and in this way, the number of variables in demanding. It does, however, eliminate the use of a toxicclinical trials can be minimized and the ﬁndings more easily agent.interpreted. 4.2. Current alternative modalities The failure of CH and the desire to ﬁnd a drug less toxic4. Pulpotomy therapy than FC initiated an extensive search for alternative pulpot- omy agents in the 1970s . The efforts of a considerable4.1. The past number of investigators have culminated in a spectrum of ways to pulpotomize primary teeth. FC has long been the standard pulpotomy agent in One of the early attempts to reduce FC toxicity was toprimary teeth, and CH the standard for immature permanent lower its concentration. Based on preliminary in vitroteeth . While the rationale for the use of FC is not clear, analyses , a 1/5 dilution was selected and subjected toit presumably ﬁxes affected and infected radicular tissue so clinical trials . It was found to be as effective as full-that a chronic inﬂammation replaces an acute inﬂammation. strength preparations. In an attempt to further reduce FCIt is the intent of the fomocresol pulpotomy that pulp toxicity, glutaraldehyde (GA) was advocated as an alterna-remains in a metastable condition until the tooth is exfo- tive to formaldehyde because it is a true cross-linking ﬁxa-liated. Even under this dubious rationale, the success rates tive . It also demonstrates less antigenicity, self-limitingwith FC have been clinically acceptable. penetration, and reduced toxicity . Clinical trials in In recent years, voices have been raised against FC primary and permanent teeth have been promising [63–because of its toxicity , and it has been banned in at 65]. The rationale for GA is the establishment of a biocom-least one country. However, the FC pulpotomy technique is patible seal over the amputated pulp, which separates itstill being taught in virtually every dental school in the from the adjacent base.United States  and in many other countries. For better Ferric sulfate (FS) has gained support as a pulpotomyor for worse, FC promises to be with us for some time. agent in primary teeth although the original rationale for CH is considerably less harsh on pulp tissue than FC its introduction has been forgotten. It was ﬁrst investigated[53,54]. Under optimal conditions it can stimulate a dentine as a hemostatic agent preparatory to the placement of CHbridge, but it is not ordinarily used for that purpose in a over amputated pulp . The intent was to determine ifpulpotomy procedure on permanent teeth. Instead, it serves hemorrhage control improved the efﬁcacy of CH, sinceto maintain the vitality of radicular tissue until apexogenesis earlier investigators speculated that the failures of CHis complete. Once the apex is closed, a root canal is were due to the persistence of blood clots between it andperformed. The practice of obturating the canals immedi- pulp tissue . For unknown reasons, subsequent studiesately upon root completion is based on anecdotal evidence have evaluated FS alone [67,68], and not as an adjunct tothat CH will precipitate dystrophic calciﬁcation in the CH, and its success rate has approximated that of FC. Fromcanals and prevent endodontics later, if it should be needed. what we know, it does not stimulate reparative dentine, andThe negative impact of CH in a classic pulpotomy, if real, it does not improve pulp responses compared to FC [69,70].may result from too little pulp tissue conﬁned with too much Perhaps the mechanisms of action of FS are to prevent clotchemical. When partial pulpotomies were performed, with formation—and its attendant inﬂammatory cascade—andthe objective of removing only infected tissue, dentine brid- to precipitate a protein barrier at the amputation site.ging was stimulated in the coronal area, and the canals were A widely divergent approach to pulpotomies in primaryfree of dystrophic calciﬁcation . teeth has also evolved in recent years. Instead of devitaliz- For a time, CH was touted as an alternative to FC for ing pulp with a chemical, electrocautery is used to burn andpulpotomies in primary teeth , but too often it was coagulate radicular tissue. A pulp so treated displays theobserved to stimulate internal resorption rather than dentine remnants of a burn—coagulated protein, necrosis andformation , and its popularity has waned. The observed inﬂammation . Clinically, the success rate of electro-resorption has been ascribed to a blood clot intervening cautery has been reported high , similar to FC ,between the chemical and pulp tissue and not to CH per and very poor .se. However, even with stringent conditions taken to avoid Lasers have been suggested as a more sophisticated
158 D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–161instrument for devitalizing pulps, but in a recent studies on We have learned that there is a family of proteins that hashuman canines, the histologic pictures of FC and laser-trea- bone inductive properties, and BMP is a generic term forted pulps were not signiﬁcantly different, and the pretext for this family.further laser research was only the avoidance of FC . BMPs are members of a highly conserved family of signalCertainly in the pulps of dogs, irradiation with laser caused molecules that have been recycled during evolution tocarbonization, necrosis, inﬂammation, edema and hemor- mediate interactions between tissues during embryonicrhage—with little evidence of repair . development. For this reason, BMP is a misleading nomen- As mentioned previously, Stanley is a strong propo- clature in that it implies a single gene product responsiblenent of CH for pulp capping and pulpotomies . He for bone formation, when, instead, each probably accountsavers that the negative side effects of inorganic CH for multifunctional gene products expressed throughouthave been eliminated in the lower pH hard-setting ontogeny. Because the osteogenic role was discovered incements. He suggests that the internal resorption and mammals and the embryonic role in phylogeneticallythe dystrophic calciﬁcation seen in pulpotomized lower organisms, a confusing multiplicity of names hasprimary and permanent teeth, respectively, are less arisen.likely to occur with commercial CH preparations. To establish some order to the terminology, the BMPHowever, these claims have not been adequately family of proteins has been renamed the DVR(decapenta-substantiated. Only one small, short-term clinical study plegic-Vg-related) family, based on the ﬁrst two members tousing a CH cement in primary teeth has been reported be identiﬁed—Drosophila decapentaplegic and Xenopus. Because CH does have favorable properties, Vg1. Table 1 of Ref.  lists the family by DVR, BMPperhaps pulpotomies with hard-setting cements should and osteogenic protein (OP) names. The DVR familybe revisited. belongs to the much larger transforming growth factor b (TGF-b) superfamily.4.3. The future From our yet inchoate knowledge, the implications of BMPs to dentistry are nonetheless enormous. The availabil- Interestingly, in the future, pulpotomies for primary and ity of commercial BMPs to predictably induce bone forma-permanent teeth may be handled in exactly the same way. tion in orthopedic, oral and periodontal surgery will beAdvances in material and biological sciences offer us at momentous . Shortly after his original report, Uristleast two therapeutic approaches, either of which could  observed that demineralized dentine also had inductivebecome common to both dentitions. From material sciences properties, and since then it has been demonstrated thatwe have seen the development of dentine adhesives, which BMP from both bone and dentine will promote dentineogen-we have already discussed in another context. From biolo- esis [82–84]. Thus, the implications for pulp therapy aregical research we have seen an explosion of knowledge immense. If BMPs can be packaged in a form suitable forabout growth factors that induce bone and dentine. The clinical usage, dentists might at last have a true biologicalpotential to acquire pulp therapeutics from these burgeoning pulp capping and pulpotomy agent. Table 2 of Ref.  listsﬁelds is worth discussing. the known BMPs and their actions when implanted into If dentine adhesives can be developed for direct pulp receptive tissue. Osteogenic potential was evaluated usingcapping, then there is no reason that they cannot be used subcutaneous implants in rats; pulp responses were deter-for pulpotomies. In fact, the chances for success should mined in dog and primate teeth.improve in the latter, simply because the purpose of pulp The data from the several pulp studies summarized inamputation is to reach a level of healthy pulp. With diseased Table 2 of Ref.  suggest that a number of BMPs aretissue removed, the response of the remaining pulp should capable of inducing reparative dentine. This should not bebe more favorable. Although we do not know of any studies surprising since BMPs probably play a regulatory role inin this area, it does seem a logical progression of the pulp cell differentiation [85–87] and human toothtechnology. Just as for direct capping, we urge a stepwise morphogenesis . In addition, receptors for them haveapproach in evaluating dentine adhesive for pulpotomies. been identiﬁed in human dental pulp . Even more exciting than dental adhesives are the recent As expected, demineralized bone and dentine haveadvances in the ﬁeld of bone morphogenetic proteins proved inductive of the same tissues, but more impor-(BMPs). The discovery of this family of growth factors tantly, recombinant human BMPs have also been shownsprang from the observation by Urist  that deminera- to be effective. Progress from crude preparations to purelized bone matrix could stimulate new bone formation when protein has been rapid. Fadavi et al.  dressed pulpo-implanted in ectopic sites such as muscle. Urist concluded tomized monkey teeth with freeze-dried bone and Naka-rightly that bone matrix contains a factor capable of shima  used dentine matrix to treat amputated pulpsautoinduction, and he named it bone morphogenetic of dogs. Narrowing the focus further, crude BMPprotein. Because these factors exist in such minute prepared from bovine bone was used to treat pulpto-quantities, it was not until the development of molecular mized dog teeth [82,91,92]. The latter studies reportedbiology that their physiologic roles could be explored. the sequential induction of osteo- and tubular dentine.
D.M. Ranly, F. Garcia-Godoy / Journal of Dentistry 28 (2000) 153–161 159The preparations of BMP were ill-deﬁned; presumably therapy in permanent teeth, might be adapted to the needsthey included BMP-2, BMP-3, and BMP-7 (OP1). of primary teeth [101,102]. Garcia-Godoy , conﬁrmed While BMP preparations from bovine or human bone the efﬁcacy of this preparation. Primary teeth with signiﬁ-would not be feasible for human teeth, molecular biology cant infection, furcal involvement and mobility were routi-techniques have fortunately circumvented the necessity of nely salvaged and retained. The rate of healing was notable.isolating BMP from bone. Recombinant human BMP-2, The material is clinically forgiving. After the canals areBMP-4 and OP-1 have been puriﬁed and characterized, prepared, the paste can be easily injected into them with aand all have shown dentine inductive potential in host CR syringe. Filling to the apices is unusual and apparentlyteeth [93,94]. Most importantly, the response to hOP-1 in unnecessary. What is crucial is the placement of the pasteprimate teeth was dose dependent, a property never before over the ﬂoor of the chamber, in order to ensure that theattributed to a pulp agent. Equally exciting is the ﬁnding that auxiliary canals traversing to the furcation are medicated.reparative dentine can be stimulated transdentine by OP-1 in Should the paste be expressed into extradental spaces, it isa dose dependent manner. The demonstration that reparative resorbed within a week or two. Evidence of signiﬁcant heal-dentine can be induced by direct or indirect contact with a ing occurs within weeks.biologic agent—and its thickness determined by dose— A newer preparation, Vitapex, a mixture of iodoform andelevates pulp therapy to a new level. Clearly, this regenera- CH, is now available in North America. Preliminary studiestive approach, if successful, would transcend all other suggest that it, too, is efﬁcacious for pulpectomies inmodalities. primary teeth . We are now entering an era when commercially availablerecombinant human BMPs will be available for experimen-tation and clinical trials. Several authors have encouraged 6. Conclusionthe evaluation of these factors as new modalities for pulp The old standbys of pulp therapy, FC, CH, and ZOE aretherapy [62,95,96]. It is exciting to think that someday we being superceded by new agents. On the horizon are biolo-might treat a pulpotomized primary or permanent molar gics and newer materials that may completely transform ourwith growth factors and predictably induce sound dentine whole philosophy of treatment. We seem to be on the brinkbridges, leaving the radicular tissue completely enclosed in of an era when a diseased pulp can be a saved pulp.healthy dentine. Primary teeth would be free of inﬂamma-tion and could exfoliate normally; the need for root canaltherapy in permanent teeth would be eliminated. References  Aponte AJ, Hartsook JT, Crowly MC. Indirect pulp capping success5. Pulpectomy therapy veriﬁed. ASDC Journal of Dentistry for Children 1966;33(3):164–6.  Stark MM, Nicholson RJ, Soelberg KB. Direct and indirect pulp5.1. The past capping. Dental Clinics of North America 1976;1:115–26.  Stanley HR. Pulpal responses to dental techniques and materials. Endodontic therapy for primary teeth has long been advo- Dental Clinics of North America 1971;15(1): 115–26.  Kerkhove Jr VC, Herman SC, Klein AI, McDonald RE. A clinicalcated when the criteria for a classical pulpotomy treatment and television densitometric evaluation of the indirect pulp cappingcannot be met . The procedure involves debridement technique. ASDC Journal of Dentistry for Children 1967;34:192–and enlargement of the canals with graded ﬁles prior to 201.obturation with ZOE . The latter should be unﬁlled so  Leksell E, Ridell K, Cvek M, Mejare I. Pulp exposure after stepwisethat they will resorb in synchrony with the roots. Unfortu- versus direct complete excavation of deep carious lesions in young posterior permanent teeth. Endodontics and Dental Traumatologynately, even pure ZOE cement is resistant to foreign body 1996;12:192–6.giant cells, and very often fragments of cement can be seen  Hawes RR, DiMaggio JJ, Sayegh F. Evaluation of direct and indirectat the site of a pulpectomized tooth that has exfoliated . pulp capping. Journal of Dental Research 1964;43(5):808. In addition to its bioincompatibility, ZOE is not particu-  Coll J, Foaoq N. Indirect pulp therapy—an alternative to pulpotomylarly antibacterial once it has set. This is a glaring deﬁcit for deep caries. 52nd Annual Session, American Academy of Pedia- tric Dentistry, 1999.because it has been shown that the root canals of primary  Massler M. In: Cheraskin E, editor. 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