Endodontics

Apexification: review of the literatureDonald R. Morse* / James O'Larnic** / Cctnil Yesilsoy**"

Five methods for the treatment of teeth with an incompletely formed ape.\ (open apex)and a necrotic pidp are discussed. The methods discussed include the u.Ke of{\) a cus-tomized cone (blunt-end, rolled eone); (2) a short-fill technique; (3) periapical surgerv(with or without a retrograde seal): (4) apexification (apical closure induction); and(5) one-visit apexification. The apexification techniques, which use various formulationsof calcium hydroxide to induee closure, are stressed. Ba.sed on the review of the litera-ture and clinical experience of the authors, it was concluded that sucee.ssful treatmentof an immature ptdpless tooth can partly result from the antibacterial atid calcifieation-indueing action of calcium hydroxide. (Quintessence Int 1990.21:589-598.)

Introduction

Apexification is a method of inducing apical closurethrough the formation of mineralized tissue in the ap-ical pulp region of a nonvital tooth with an incom-pletely formed root (open apex). The mineralized tis-sue can be composed of osteocementum. osteodentin,or bone or some combination of the three.' Apicalclosure can take various forms. It can be a compieteor an incomplete hard tissue bridge a few millimetersshort of the end of the root. It can be located at thetip of the root, or the bridging can be an irregularmass of calcification traversing the apical one third ofthe root. In most cases, apicai closure takes an irreg-ular and aberrant form.' Along with apical closure,root development or lengthening may or may not con-tinue, but whatever the form, root development is usu-ally irregular and aberrant. In contrast, apexogenesistreatment (vital root-end closure) results in regularapical closure and normal-appearing root develop-ment.

Currently, there are at least five methods of treatinga tooth that has a necrotic pulp and an open apex.These methods are (1) filling the root canal with thelarge (blunt) end of a gutta-pereha cone or customizedgutta-percha cones with a sealer; (2) filling the rootcanal well short of the apex (before the walls havediverged) with gutta-percha and sealer or zinc oxide-eugenol (ZOE) alone; (3) filling the root canal withgutta-percha and sealer as well as possible and thenperforming periapical surgery with or without a re-verse seal; (4) inducing apical closure by the forma-tion ufan apical stop (calcium hydroxide [Ca(OH))]is generally used) against which a permanent root can-al filhng can subsequently be inserted; and (5) placinga biologically acceptable substance in the apical por-tion of the root canal (dentinal chips or tricalciumphosphate have been used) thus forming an apicalbarrier; this is followed by filling the root canal withgutta-percha and sealer. The last procedure has beencalled one-visit apexification.'"' Each of these tech-niques will be examined.

Professor and Research Director. Department of Endodontol-ogy. Temple University, School of Dentistry, 3223 NorthBroad Street, Philadelphia, Pennsylvania 19140.Formerly, Second-Year Graduate Student, Department of En-dodotitology. Temple University. Presently, Private Practice,Philadelphia, Pennsylvania.

Associate Professor and Director of Undergraduate Clinic,Department of End odon to logy. Temple University.

Blunt-end or rolled cone (cnstomized cone)

Filling the root canal with the large end of a gutta-percha cone or a customized cone is not advisablebecause the apical foramen i.'; generally wider than theroot canal orifice. '' This would prevent proper con-densation of the gutta-percha, and proper preparationof the canal would weaken the tooth considerably.'" Itwould also he difficult to assess the point of root de-

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vdopmcnt radiographically because root formation inthe buecolingual plane is less advanced than it is inthe mesiodistal plane."

Short-fill

Moodnick'" proposed removal of the bulk of the ne-crotic tissue and tilling the root canal short of theapex with gutta-percha. He advocated use of Diaket*'"(Premier Dental Products), a compound of beta-ke-tones and zinc oxide, in place of gutta-percha to en-hance healing. However, with an incomplete obtura-tion, microbes can be left remaining within the apicalpart of the root canal system, and healing may nottake place or periapical breakdown may occur later."

Periapical surgery

The gutta-percha/sealer surgical approach has manydrawbacks. Many clinicians''"'''"''* do not advocate thismethod of treatment for one or more of the followingreasons:

1, Relative to the already shortened roots, further re-duction could result in an inadequate crown-to-rootratio.

2, Surgery could be both physically and psychologi-cally traumatic to the young palient,

3, The young patient is not apt to be cooperative,4, Surgery would remove the root sheath and prevent

the possibihty of further root development,5, The apical walls are thin and could shatter when

touched by a rotating bur,6, The thin walls would make condensation of a re-

trograde material difficult. This can result in aninadequate seal,

7, The periapical tissue may not adapt to the wideand irregular surface of the amalgam.

However, for cases in which a more conservativeapproach is not feasible, Dawood and Pitt Ford-' havegiven evidence that tbe obturation of the root canalwith thermoplasticized gutta-percha/sealer followedby periapical curettage can be clinically sticcessful.

Apical closure induction

Induction of apical closure or an apical stop has be-come the most widely used approach to treating theseteeth. Many materials and metbod.s have been usedsuccessfully, but the exact mechanism of action re-mains a mystery. It has been considered that in the

treatment of teeth with a necrotic pulp, the basic aimshould be stimulation and preservation ol the torm-ative activity of the granulation tissue cells in the ap-ical part of the root canal. This should enhance theformation of a calcified callus in the wide apical open-ing,--

The use of Ca(OH), to induce apical closure wasfirst introduced in 1964 by Kaiser,-' when he proposedthat use of CaiOH): mixed with camphorated para-chlorophenol (CMCP) would induce the formation ofa calcified barrier across the apex. His procedure waspopularized in 1966 by Frank,'* who described a step-by-step technique and four types of apical closure. Forthe procedure to be effective, it has been hypothesizedtbat Ca(0H)2 paste must contact vital tissue, althoughthis has never definitely been proven."'' It has also beenshown that the larger the apical opening, the longerthe time necessary to induce apical closure. However,no consensus exists on how frequently the dressingshave to be changed to induce apexification,'''"-'•''-''

Heitbersay"-' and others-**-' have induced apiealclosure using Ca(0H)2 and methylcellulose {Pulpdent,Pulpdent Corp), Pulpdent has the advantages of de-creased solubility in tissue fluids and firm physicalconsistency,-'

A different approach with Pulpdent has been usedby Senzamici and Tesini, " In their technique, a mastercone is fitted 3 mm from the apex, and, prior to ob-turation, the apical 3 mm is filled with Pulpdent,

Nygaard-Ostby^' suggested laceration of the periap-ical tissues with a file until bleeding oceurs, to resultin the further development of the root apex,Zussman" showed that the vascularity of the apicalregion facilitates and favors further root developmentby the root sheath once the tissues are in a healthystate. However, Ham and coworkers" have not re-ported much success with the induced blood clot, "and Citrome and coworkers''' have reported that theblood clot maintained the initial infiammatory stateand did not result in hard tissue bridging at the apex.

Rule and Winter'" utilized instrumentation to in-duce bleeding and believed that this tissue may havenot undergone necrosis and could therefore aid in fur-ther apical closure and root development. Torneck andSmith"" reported that any attempt to retain a residualpulp stump in the apical one third of the root canalresults in the formation of a periapical abscess. Theyalso reported that, despite the absence of remedialtherapy, continued root growth can occur. The calcificbridge at the apex in some eases appears lo be relatedmore to the ingrowth of trabecular bone.

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Endodontics

Leibeiman and Trowbridge" and Barker andMayne'' haye reported cases of root-end closure with-out pulp therapy or endodontic therapy, Israel"" wasable to obtain continued apical development after useof biomechanieal cleaning alone. Das'' consideredthat minima! mechanical intervention and removal ofinfection alone would be suffieient to induce apicalclosure. Conversely, other studies'" ""- have reportedthat cases in which the root canals were thoroughlycleaned and shaped had a decreased incidence of rootformation compared to eases in which the root canalswere instrumented less thoroughly, England and Besf"stated that the thorough cleaning of the root canalmay be the primary factor responsible for apical clo-sure. They believed, as did Chawla and coworkers,*"that a catalyst paste is unnecessary to induce apicalclosure. Some investigators'* '"^ concluded that, al-though apexification is a natural phenomenon, it mustbe stimulated by a biologic activator,

Klein and Levy''' and others"" "" have successfullyinduced apical closure using Ca(OH)2 and Cresatin(Premier Dental Products), a metacresylacetate,Weiss,'" using tiiis mixture as a pulp capping agent,reported more rapid healing with it than with the useof Ca(OH); and water,

Cresatin has been shown to have minimal infiam-matory potential as a root canal medicament" andminimal cytotoxicity when compared with CMCP, ^Camphorated parachlorophenol has also been shownto be a highly toxic preparation capable of causingtissue necrosis. However, Dylewski ' saw no evidenceof irritation after use of CMCP in the periapical tis-sues of monkeys.

If CMCP or Cresatin is mixed with Ca(OH):, achemical reaction occurs and results in the formationof the calcium-p-chlorophenolate and calcium cresy-late salts, and, after 2 weeks, Ca(OH); and Cresatinhave been observed to form acetic aeid, "" These com-pounds are difficult to remove from root canals.'" Ithas also been shown that the combined pH of Cresatinand Ca(0H)2 decreases faster than the pH of the com-bined CMCP and Ca(OH):.

Calcium hydroxide, when mixed with a number ofdifferent substances, has been succe.ssful in inducingapical closure,' • ' Since its introduction, Ca(OH), hasbeen mixed with CMCP.' distilled water," sterilewater,' • '•" sterile saline, "-*' anesthetic solutions (pref-erably without vasoconstrictors),''- chlorothymonal,*^Cresatm, Cresanol (Premier Dental Products), a mix-ture of CMCP and Cresatin, Ringer's solution, meth-ylcellulose, and todoform,'"" In some formulations.

glycerine has been added to improve the consistency,and barium sulfate has been added to make the pastemore radiopaque."* However, Smith and Woods'* sug-gested that the use of diatrizoate compounds (solubleorganic iodine) be used as a substitute for bariumsulfate. The diatrizoate compounds are resorbable andwill not obscure the apex if the paste is extruded peri-apicaily.

Other pastes have been used to induce apical clo-sure, including pastes that contain antibiotics, - '' ^Cooke and Rowbotham'"* used an antiseptic paste con-taining zinc oxide, cresol, clove oil, iodoform, and thy-mol. Other investigators*'- ' consider this apical pasteto be a protoplasmic poison that would further irritatethe periapical tissues.

When Vojinovic and Srnic'" eompared the use ofCa(OH)i to the use of iodoform Chumsky paste (30g phenol, 30 g camphor, 110 g absolute alcohol), theyfound more calcified tissue and a more complete clo-sure with Ca(OH);, They beUeved that, although somestimulation of the eells of the granulation tissue isnecessary, the paste was more irritating than is nec-essary.

Other materials that have been used with some suc-cess are Calosept (Scania Dental)," an iodoform-eon-taining paste," Hypocal (Ellman Co)," a chloromy-cetin-containing paste,"* and ZOE pastes,"

Bernard" showed that apical development occurredafter sterilization of the periapical tissues followed byfilling of the root canals with a calcium oxide-con-taining paste, Matsumiya and Kitamura'* comparedthe effect of antibacterial treatment using antisepticand antibiotics with the effect of physiologic salinebefore the canals were filled with Ca(0H)3. The com-parison was a histopathologic and histobacteriologicexamination of the root canals from the teeth of in-fected dogs. There was no statistically significant dif-ference between the two groups. This can be relatedto the long-term antibacterial effect of the Ca(0H)2,which has heen demonstrated, in vitro, to be bacte-ricidal and antiseptic. According to some authorities,the chance of a successful outcome are lessened if anegative microbiologie culture cannot be obtained,"The formation of calcified tissue is considered to oecurin the absence of microorganisms.'"* It has beenshown that Ca(0H)2 accelerates hard fissue bridgingat the apex irrespective of the initially induced infiam-matory state, "'

A study by England and Besf* found that apicalclosure occurred more frequently in teeth left open tothe oral environment (86,5%) than in those closed to

rnationa) Number 7/1990 591

Endodonties

it (50%). This was in agreement with Torneck et al,""who hypothesized that exúdate in the closed root eanalhas no pathway for drainage. This fiuid can accu-mulate in the root canal, thus impeding repair.Ludlow' reported on a case in which a tooth with alarge periapieal lesion did not respond to Ca(OH);and CMCP treatment until the lesion was curetted.

The mechanism of apieal closure is still in question.Some investigators''•'*'*'°- ' believe that the root sheathremains intact and resumes its function once thesource of infection is eliminated. Klein and Levy 'believed that the ceils of the dental sac around theapex retain their genetic code that predisposes themto form into cementoblasts. Torneck and Smith'*maintained that remnants of the dental pulp remainvital and function in spite of inflammation. Therefore,confinued root development can be a feature of thechronic phase of pulpal disease and is not necessarilya product of treatment.

In other studies in which apical elosure was induced,it was not possible to identify the root sheath in anysection of teeth with either partial or complete rootclosure. West and Lieb*" reported a ease in which theperiapex of an incisor was curetted following conven-tional endodontic therapy. After II years, the toothwas then sueeessfully treated by the use of Frank'stechnique.

Some investigators have proposed that Ca(0H)2stimulates undifferentiated mesenchymal cells to dif-ferentiate into cementoblasts, which, in turn, initiatecementogenesis at the apex."*"*- Dylewski' observedproliferating connective tissue in the apical region thatdifferentiated into calcific material, whieh becamecontinuous with the predentin at the apex. Sehroderand Granath" maintained that this calcification pro-cess occurs beneath a superficial layer of necrosis.They considered that the necrosis was related to thehigh pH of the Ca(OH):.

Heithersay" considered that the alkalinity of thematerial can act as a buffer to acidic inflammatoryreactions. As a result, the Ca(0H)2 has a favorableeffect on bone healing. Tronstad and coworkers*" haveshown thai the pH of untreated teeth with pulpal ne-crosis is between 6.0 aud 7.4. Teeth with complete rootformation have a pH between 7.4 and 9.6 in the dentinaway from the pulp and from S.O to 11.1 in the dentinnext to the pulp. These investigators maintained thatthe Ca{OH)- neutralizes acids produced by osteo-clasts. Anthony and coworkers-'' concluded, that thealkaline environment would favor the formation ofcalcium phosphate (Ca[PO].i) complexes, whieh

would, in turn, serve as a nidus for further calcifica-tion. Javelet and coworkers** also indicated that thealkalinity is a significant feature in the abihty ofCa(0H)2 to induce hard tissue formation. Otherinvestigators""-"' contended that Ca(OH): creates anunfavorable environment for osteoclastic activity orcan activate alkaline pbosphatase enzymes. The latterhave been suggested as playing a role in hard tissueformation. Yesilsoy and coworkers"" have shown thatCa(OI-I);, hy itself and as a component of root canalsealers, can induce calcification even in a soft tissueenvironment.

When preparing the Ca(OH): paste using anestheticsolutions, Stamos and coworkers*' determined thatsuch a small amount of liquid is used that no appre-ciable change occurs in the pH. Mitchell atidShank walker'*" concluded that it is difficult to ascriheany importance to the pH of the material when theosteogenic potential is considered. They rationalizedthat the use of other materials that have relatively highpH values do not result in consistent hard tisstie for-mation. This is also supported hy the investigationsof Binnie and Mitchell.'"

McCormick and eoworkers'- maintained that therehance on medication alone'" to aeeompli.sh a pH risein the periapex, as proposed by Van Hassell and Nat-kin," is unrealistic. They beheved that other proce-dures are of considerable importance in gaining con-tinued apical development. These procedures include( 1) adequate preparation of the root eanal; (2) re-moval of necrotic tissue and substrate; (3) reductionof microbes (both in terms of numbers and virulence);and (4) a decrease in the root canal space. Frank'*'''concluded that the reduction of contaminates in theroot canal and the filling of the root eanal space witha temporary resorbable material are more importantthan which material is tised.

Nyborg^' and other investigators"''*-^' thought thatpulpal reaetion to Ca(0H)2 depended on the hydroxylion rather than the calcium ion. Nevertheless, in onestudy,''"' in which magnesium hydroxide (Mg[0H]2) wasused in 14 apexification procedures, the results showedfour mild and ten severe inflammatory reactions. Con-tradictory results were found when Mg(0H)2 was im-planted subdermally in rats." Magnesium hydroxidewas found to have less of an inflammatory reactionthan has CaiOH),. In one investigation,*" barium hy-droxide was substituted for CaiOH);. Observationsfrom this study included a lack of bridge formation,a severe foreign body reaction, and acute and chronicinflammation with epithelial proliferation.

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Endodontics

The calcium ion was also thought to be necessaryto decrease capillary leakage and constrict the pre-capillary sphincters." In addition, the calcium ion canalso affect the enzyme pyrophosphatiise, which is cal-eium dependent. Pyrophosphate is involved in eolla-gen synthesis and. therefore, stimulation of thi.s en-zyme can increase the defense and repair mecha-nisms.-'

Nevins and coworkers^* used a Ca(P0)4 gel to pro-dtice a mineralized scar around the orifices of poly-ethylene tubes that were placed subcutaneously in rats.When plaeed in pulpless open-apex teeth in monkeys,the gel resulted in connective tissue ingrowth.**" Nevinset al ' postulated that this could be a step in revitali-zation of teeth. In other studies, the Nevins group alsoreported the sueeessful use of collagen Ca(P0)4ggl 100,101 Donlon'"- has shown that calfskin collagenis lmmunologically neutral. In contrast, Citrome andcoworkers''* found that, in dogs, the collagen Ca(P0)4gel inhibited the reparative process of the initial in-flammatory lesion, leading to extensive destruetion ofthe periapical tissues. No evidence of apexificationwas found. Heuer'"' reported that collagen Ca{P0)4gel failed to assist in the resolution of instrumentationtrauma and inhibited tbe repair process. Teeth treatedwith Ca{OH); in the same animals showed an accel-eration of the repair process.

Finally, whether or not a eomplete apical barrierresults from apexification techniques is uncertain. Lie-berman and Trowbridge-" have shown that even withradiographie and ehnieal evidence of a hard tissuebarrier, histologie examination shows that this barrieris porous. Nevertheless, for clinical success, it may notbe necessary to have an impermeable hard tissue bar-

One-visit apexification

The most recent development in the treatment of teethwith a necrotie pulp and an open apex is to condensenonsurgieally a biocompatable material into the apicalend of the root canal. The rationale is to establish anapical stop that would then enable the root canal tobe filled immediately This technique has been calleda one-visit apexification. However, it really only fulfillsone aspect of apexification: the creation of an apicalstop. It does not allow for continued root develop-ment. Hence, the technique eannut be used for teethwith excessively short roots.

A resorbable ceramic has also been developed. It isa specially prepared form of calcium phosphate that

(1) acts as a matrix for the invasion of blastic cells,(2) allows for cellular proliferation and differentia-tion, and (3) permits deposition of hard tissue. Stud-ies have shown thai resorbahle ceraniie is replaced bybone. "' "'5

Koenigs and coworkers'"'' simulated conditions ofan open apex in 24 monkey teeth and packed the ap-ical 3 to 4 mm with caleium phosphate ceramic. Atthe end of a 24-week period, most of the material hadbeen resorbed and repliiced by a mineralized tissuethat contained nuclei. The tis.sue extended 3 lo 5 mminto the root eanal, and it resembled cementum. Theperiodontal ligament had regenerated with little, ifany, inflammation ofthe periapical tissues. However,the bridge was not complete, and a small channel,containing connective tissue and blood vessels, wasobserved on one lateral wall.

Roberts and Brilliaut" ' compared apical closure in-ducement between triCa(P0)4 (pH = 8.6) andCa(0H)2 (pH = 12.0). Both substances are relativelysuccessful. They concluded Ihat the use of a highlyalkaline material is unnecessary to induce closure andfelt that particle size might be a factor. TriCa(P0)4and Ca(0H}2 had nearly identical particle sizes(Ca[OH]> = 2 to 5 \im- triCa[PO]4 = 3 to 5 i m).

Covicllo and Brilliant""* compared a one-appoint-ment technique using either Ca(OH); or triCa(PO).i.Both substances proved successful, but. in contrast tothe previously mentioned .study,"" more CaiOH), wasneeessary to create the apical stop. This result wasprobably due to discrepencies in particle size.

Dimashkieh'' ' devised a technique using Surgicel(Ethieon Ltd) along with amalgam. Surgicel is an ox-idized regeneration cellulose that is nonirritating andresorbable. After preparation of the root canal, theSurgice! was inserted through the aeeess opening andpacked apically. This was followed by insertion of theamalgam in the same fashion. Hence, the Surgical wasused as a base and/or matrix.

Rossmeisl and coworkers"*•"' used freeze-dried eor-tieal bone and freeze-dried dentin to create apicalplugs. They found that both materials were bioeom-patible with periapical tissues. The freeze-drying pro-cedure appears to inactivate the histocompatibie an-tigens."^"-'

The use of dentinal shavings as a root canal filhngmaterial was first described by Gollmer"* in 1937.Tronstad"- has found dentinal chips to be well toler-ated by periapical tissues. Others'"'"' have found thatthe use of dentinal chips increases the formation ofosteocementum in the peri apex.

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Table I Summary of techniques for trealment of nonviial teeth that have an open apex

TechniqueRoot-endclosure

Histologieresponse Appointments Prognosis

Untreated"''

Instrumentation alone''' *''"'

Customized cone^"'"

Short mr-

Periapical surgery ''"''''"-''

Apexification

Calcium hydroxide'''"-*'

Magnesium hydroxide '*'*'

Barium hydroxide^"

Zinc oxide"-* '''

Calcittm oxide"

Calcium phosphatecollagen gel'*"'"

Tricalcium phosphate'"'

Other pastes™ "

One-visit apexification

Resorhahle ceramic'"^'"^

Tricalcium phosphate'"*

Calcium hydroxide'"*

Surgi eel/amalgam'"^

Freeze-dried bone oror dentin"«-"'

Yes, but onlycase reports

Yes, but may bedecreased amount

No

Yes, but onlycase reports

No

Yes

No

No

Questionable

Yes

Questionable

Yes

Questionable

No

No

No

No

No

Questionable

Questionable

Unfavorable

Questionable

Unfavorable

Favorable

Questionable

Unfavorable

Unfavorable

Questionable

Questionable

Favorable

Questionable

Favorable

Favorable

Favorable

Questionable

Favorable

None

1-2

2-3

2-3

1

6-7

6-7

6-7

6-7

6-7

6-7

6-7

6-7

1

1

1

1

1

Poor

Questionable

Poor

Fair

Generally good

Poor

Poor

Poor

Fair

Questionable

Generally good

Questionable

Fair

Fair

Fair

Fair

Fair

Weisenseel and associates"*' compared apical sealsof root canals mechanically prepared to simulate openapexes. The root canals were then filled with eithergutta-percha and Tubli-seal (Kerr/Syhron Corp)alone, or an initial placement of a 2-mm apical plugof Ca(OH); before the gutta-percha/sealer combina-tion. The resuits indicated that the root canals withapical plugs (CA[OH]i) demonstrated significantly lessleakage than did those without the plugs.

Discnssion

Five methods are primarily used to manage teeth withan open apex and a necrotic pulp: (i) use of the bluntend of a gutta-percha cone or rolled gutta-perchacones; (2) obturation of the root canal short of theapex; (3) performance of periapical surgery with orwithout a reverse amalgam seal; (4) use of an apex-ification procedure to create an apical stop: and (5)

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Endodontics

use of a one-visit apexification procedure by con-densing a biologically acceptable material in the apexfollowed by obturation of the rest of the root canalwith gutta-pereha/sealer {Table 1),

Tbe most frequently used procedure appears to beapexification with Ca(OH);, Its relatively good successhas been attributed to one or more of the followingproperties: (I) tbe pH; (2) the calcium ion: (3) thehydroxyl ion; and (4) the antibacterial effect. How-ever, tbe property that actually promotes the mecha-nism for calcific bridge formation is not known. Be-fore a wound can heal properly, the bacteria in thearea must be removed, inactivated, or greatly reducedin number. Although Ca(0H)2 possesses antibacterialproperties, apexification has also been successful with-out the use of this medicament. The common aspectsof all apexification procedures are debridement, clean-ing, and reduction of the root canal space with a ma-terial, thus leading to a favorable periapieal environ-ment,"'*'" Once the infection is eliminated and the peri-apical tissues reorganize, it is then possible for calcificdevelopment to take place.'-" Frank"" has stated tbatCa(OH); paste is often used as a temporary paste fill-ing because of its availabihty and its comparative easeof removal rather than because of any unique effect.

With the current popularity of single-visit endodon-tics,'-' tbere has emerged a single-visit apexification asthe result of the formation of an operator-made apicalbarrier. The successful performance of this one-visitprocedure benefits both patient and practitioner be-cause of the reduced amount of office time required.The problem of patient compliance is also reduced,and this can eliminate the problems that can arise withextended treatments. In addition, it appears that withmultiple visits, the reopening of the root canal, andits recieaning, disturbs the process of apexification."'-''However, there are reports of conflicting results withone-visit apexification procedures-'"^-'"' This techniquehas been performed on dogs, monkeys, and humansand in cases of (I) intact, healthy teeth; (2j experi-mentally infected teeth; (3) teeth with a naturally wideopen apex; and (4) teeth with a simulated open apex.To evaluate one-visit apexification properly, a stand-ardized method bas to be devised.

Conclusions

The eventual successful outcome in the treatment ofan immature pulpless tooth can partly result from theantibacterial and calcification-inducing action of cal-

cium hydroxide. Which Ca{0H)2 preparation is bestis unknown. Suggestions include Ca(OH)2 with dis-tilled water, sterile saline, local anesthetic solution,Cresatin, CMCP, methylcellulose, resins, and othersubstances. However, there is no evidence of the su-periority of any combination over plain Ca(OH)i. Inaddition, the major factors appear to be the debride-ment of the root canal and the reduction of the rootcanal space with a space-occupying material. The lat-ter two aspects appear to allow the body to reorganizeand repair the periapical tissues.

To evaluate one-visit apexification further, a sland-ardized method or model must be developed to com-pare the various materials being advocated.

References

1, Nicholls E: Endodomics, ed 2, BrÍ!.tol, England, John Wrightand Suns Ltd, 1977, pp 254, 258.

2, Ienica JI, Tsamtosouris A: Continued root end devdopmcm:apexogenesis and apexification. J Pedod Í978;3:144 156.

3, Engländer JA: Treatment of non-vital leeth with incompleteiyformed roots. J Dent Med 1956;2:90-96.

4, Israel H; Treatment ofan acuteiy infected fiiictiired in;:isorwith open apex. Dem Items Interest t950;72:472-476.

5, Hare G: Obliteration of the root canal with open apes. ,t En-dodontia l948;3:51-35,

6, Hartsook JT: Pulpal therapy in primary and young permanentteeth. Dem Clin Noi-lh Am l966;IO:377-389,

7, ingle J Obliteration of" Ihe llaring apical foramen, Dp'i/Digct/1956:62:410^12,

S. Pollack JR: Endodonlia lor non-vilal teeth with incompletelyformed roots. Bult NJ Soc Dem Child iy67;4:2-6,

9. Friend LA: The root treatment of teeth with open apices. FrocRoy Soc Med Odomol 1966:19:1035-1036,

10, Friend LA: The treatment of immature teelh with non-vitalpulps, J Br Endod Soc 1967;l:28-33.

11. Seltîer S: Endodonlology: Biologic Considerations in EndodonticFroeedures. ed 2. Philadelphia, Lea & Febiger. 1988, pp 31-54.

12, Moodnick RM: Clinical correlation of the development of theroot apes and surrounding structtires. Oral Sarg Oral Med OralPathol 1963;16:6Oi)-607,

13. Morse DR, Esposilo JV, Pike C, et al: A radiographie evalu-ation of the periapical status of teeth treated by the gutta-percha-eircapercha endodontic method: a one-year follow-upstudy of 458 root canals. Oral Sui-g Oral Med Oral Pathol19B3;55:607 610, 56:89-96, 56:190-197,

14. Steiner JC, Dow PR, Cathy GM: Inducing root end closureof non-vital permanent teeth. J Dem Child 1968;35:47-54.

15, Heithersay GS: Stimulation of root formation in incompletelydeveloped pulpless teeth. Oral Surg Oral Med Oral Pathol1970;2962O-630,

16, Frank AL: Therapy for the divergent pirlpless tooth by con-tinued apical formation, J Am Dent Assoc 1966;72:87-93.

17. Duell RC: Conservative endodontic treatment of the open apexin three dimensions, Dent Clin North Am I973;17:125-134.

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18, MichaLiowicz J, Michanowicz A: A conservative approach andprocedure to fill an incompletely Ibrmeil root using calciumtiydroside as an Lidjuncl. / Dem Child l%7;.12:42-47.

19, Zeldow LT: Endodontic ti-eatment of vital and m>n-vil:il im-mature leeth, NY Slate Dem J t%7;.13:Í27-í35.

20, Wakai WT, Naito RM: Endodontic niíinagement of teeth withincompletely formed rools, J Tenn Dent A'isoe 1975;55:134-t37,

21, Dawood AJS, Put Ford TR: A surgical approLich to the oti-turation of apically tlared root i;anals with thernioplasticizedgutia-percha. Im Endod J t989:22:138-141,

• 22, Vojinovic O: Induction of apical formation in immature teethby different endodontic methods of treatment, J Oral Reluihilt974;l:9t-97,

23, Kaiser HJ Management of Wide Open Apex Canals wilh Cal-cium Hydroxide. Presented at the 21st Annual Meeting of theAmerican Association of Endodontists, Washington, DC,April 17, t964.

24, Mitchell DF, Shankwalker GB: Osteogenic potential of cal-cium hydroxide and other materials in soil tissue and honewounds. J-Dem Res t958;37:1157-1163.

25, Rasmussen P, Mjor lA: Calcium hydroxide as an ectopic boneinductor in rats. Scand J Dem Rc^ l<)71:79:24-.30.

26, Schröder U: Effect of an extra-pulpal blood clot on healingfollowing experimental pulpotomy and capping with calciumhydroxide, Odomol Rev 1973;24:257-258.

27, Heithersay GS: Calcium hydroxide in the treatment of pulplessteeth with associated pathology, J Br Endod Soi 1975:8:74-93.

28, Feiglin B: Differences in apex formation during apexificationwith calcium hydroxide paste. Endod Dent Traiimiitol19S5;l:195-t99,

29, Anthony DR, Senia ES: The use of calcium hydroxide as atemporary paste fill. Ten Dem J t981;g9:()-10.

30, Senzamici NP. Tesini DA: An approach to obturation usingapical maturity as a consideration in endodontic treatment ofyoung permanent ieeth, ./ Pedod 1977;l:177.-tB3.

31, Nygaard-Ostby B: The role of the blood clot in endodontictherapy. Acra Odomol Scand t961;19:323-346,

32, Zussman WV: The interaction of ameloblasis and odontoblastsin transplants Oral Surg Oral Med Oral Pathol I%6;2I:3R8-396,

33, Ham JW, Pattersoti SS. Mitchell DF: Induced apical closureof immature pulpless teeth in monkeys. Oral Surg Oral MedOral Palhol 1972;33:438^49.

34, Citrome GP, Kaminski EJ, Heuer MA: A comparative studyof tootti apexification in the dog, J Endod l979;5:290-297.

35, Rule DC, Winter GB: Root growth and apical repair subse-quent to putpal necrosis in children. Br DenI J 1966;tt4:586-590,

36, Tomeck CD. Smith J: Biologic effects of endodontic proce-dures on developing incisor teeth, t. Effect of partial and totalpulp removal. Ond Surg Oral Med Oral Pathol 1970;30:258-266,

37, Lieberman J. Trowbndge H: Apical closure of non-vital per-manent incisor teeth where no treatment was performed: a casereport. J Endod 1983;9:257-260,

38, Barker BCW, Mayne JR: Some unusual cases of apexificationsubsequent to trauma. Oral Surg Oral Med Oral Polhot1975;39:144-150,

39, Das S: Apexification in a non-vital tooth by control of infec-lion, J Am Dent A.'^noc 1980; 100:880-881,

40, Torneck CD, Smith JS, Grindall P: Biologic effects ol' erdo-dontic procedures on developing incisor teeth II Effecl of pulp

injury and oral contamination. Oral Surg Orul Med Orul Pu/;j<in973;35:378-388,

41, Torneck CD, Smith JS. Grindall P: Biologic effects of endo-dcnlic procedures on developing incisor teeth. III. Effect ofdebridenienl and disinfeclion procedures in the treatment ofexperimentally induced pulp and periapical disease. Oral .Suri;Oral Med Orat Pathal 1973:35:532-540,

42, Torneck CD, Smith JS, Grindall P: Biologic effects of endo-dontic procedures on developing iticisor teeth, IV, Effects ofdebridement procedures and calcium hydroxide-camphoratedparachlophenol paste in the treatment of experimentally in-duced pulp and periapical disease. Oral Surg Oral Med OrulPaihol 1973:35:541-554.

43, England MC Jr, Best E: Noninduced apical closure in imma-ture roots of dog's teeth. J Endod t977;3:41]-417.

44, Chawla HS, Tewari A, Ramakusbnan E: A study of apesilVcation without a catalyst paste, J Dent Child t980;47:43i-434.

45, Arens DE: Apesification. pulp capping and pulpotomy, inClark JW (ed): Clinical Demistry. vol 4, New York, Harper &Row, 1976. pp 1-16.

46, Cooke C, Rowbotham TC: Root canal therapy in non-vitalteeth with open apices. Br Dent J 196Q;10K:147-]5Ü.

47, Klein SH. Levy BA: Histologie evaluation of induced apicalclosure of a human pulpless tooth. Ond Surg Oral Med OralPathol 1974:38:954-959.

4S. West NM, Lieh RJ: Biotogic root-end closure on a traumatizedand surgically resecied maxillary central incisor: an alternativemethod of treatment, Endod Dent Traumatol 1985;1:I46"149,

49. Stewart GG: Calcium hydroxide-induced root healing. J AmDem Assoc 1975:90:793-800.

50. Weiss M: Pulp capping in older patienls. .¥!' State Dent J1%6:32:451.457.

51. Schilder H. Amsterdam M: Inflammatory potential of rootcanal medicaments: a preliminary report including nonspecificdrugs. Oral Surg Oral Med Oral Palhol 1959;12:2I1-221.

52. VanderWall GL, Dowson J. Shipman C: Antibacterial efficacyand cytotoüicity of three endodontic drugs. Oral Surg OralMed Oral Pathol Í972;33:23O-241.

53. Dylewski JJ: Apical closure of non-vital teeth. Oral Surg OralMed Oral Pathol 1971 ;32:83-89.

54. Anthony DR, Gordon TM, del Rio CE: The effect of threevehicles on the pH of calcium hydroxide. Oral Swg Oral MedOral Palhol 1982; 54:560-565,

55. Laws AJ: Calcium hydroxide as a possible root filling material,NZ Dent J 1962:58:199-204,

56. Cvek M, Hollander L. Nord CE: Treatment of non-vital per-manent incisors with calcium hydroxide. Part VI, A clinicalmicrobiological and radiological evaluation of treatment inone sitting of teeth with mature or immature roots, OdontolÄfv 1976:27:93-105.

57. Birnie WH, Rowe AHR: A histológica! study of the periapicaltissues of incompletely formed pulpless teeth filled wilh calciumhydroside, J Dem Res 1973:52:1110-1116,

58. Wechsler SM, Fishelberg G, Opderbeck WR, et al: Apexin-cation: a valuable and effective chnical procedure Gen Dent1978:26:40^3,

59 Lin LM, Chance K, Skribner J: Calcium hydroxide in endo-dontic therapy. Comp Contiii Edue Dem 1980:7:122-t29,

60, Bicsterfield RC, Taintor JF: Root end closure in adults: reportof cases, / Endod 1980;6:69l-695.

61, Gallagher CS, Mourino AP: Root end induction. J Am DentAssoe 1979;9H: 578-580.

596 Quintesse nee Jutai 7/1990

Endodonties

. Webber RT: Apexogenesis versus upexificiition. Dent ClinNorth Am 19B4;28:659-697.

. Stewarl GG, Gautier RF: Reduced liinatnmatory root canalmedication. Oral Surg Oral Med Oral Piithol 1962;! 5:715-720.

. Holland R, De Sotiza LD, Taeliaviiini RL, et al: A histologiealsludy ol" itie effect of calcium hydroxide in the treatment ol"piLlpless teelh of dogs. J Br Enilod Soc 1979:12:15-23.

. Harrison LM: Continued apical formation m tlie imniauirenon-vital tooth. J i n Dem Assoc t969;27;6-9.

. Sraitti GN, Woods S: Organic iodine: a substitute for bariumsulfate in apexificalion procedures. J Endod 15E3;9:153-155.

. Ball J: Apical root formation in a non-vital immature per-manent ineisor. Br Dent J 1964;116:lñ6-167.

. Herbert WE: Three cases of disturbance of caleifieation of atooth and infection of the dental pulp following trauma. DemPract W59;9:t76-180.

. Winter GB: The root treatment of infected permanent incisorsin children. Br Dent J 1966;120:ll-n.

. Vojinovic Ü, Srnié E: Induction of apical formation by the useof calcium hydroxide and iodo form-Chu msky paste in the en-dodontic treatment of immature teeth. J Br Endod Soc1975;8:16-22.

Ghose LJ, Baghdady VS, Hikmat M Apexification of im-mature apices of pulpless pennanenE anterior teeth with tal-cium hydroxide. J Endod i987;13:285-290.Bouehon F. Apex formation following treatment of necrotizedimmature permanent incisors. / Dent Child 1956;33:378-38Ü.

. O'Riordan M: Apexiñcation of deciduous ineisor. J Endod1980;6;607-609.

. Rowe AHR, Binnie WH: Histologieal study of the periapicaltissues of incompleiely lormed pulpless teeth filled with zincpreparations and with magnesium hydroxide. J Dent Res1974;53:605-608.

Bernard P: L'ionophorise la Physiotechnie. Pans, Fotetto, 1957.Matsumiya M, Kitamura M: Histo-patliological and histo-bacteriological studies of the relation between the condition ofsterilization of the lrtterior of the root canal and the heahngprocess of Ihe periapical tissues in experimentally infected rootcanal treatment. Bult Tokyo Dent Coll 1961:1:1-9.Crabb HSM: The basis of root-canal therapy. Dent Pract DentRee

:. Boyle PE: Kronfeld's Histopathohgy of the Teeth and TheirSurrounding Structures, ed 4. Philadelphia, Lea & Febigei,1955, pp 238-240.

. Ludlow MO: Apical closure after nonsurgical apical curettage.y &ií/oá 1979;5:151-153.

. Smith JW, Leeb IJ. Torney DC: A comparison of calciumhydroxide and barium hydroxide as agents for inducing apicalclosure. J Endod 1984,10:64-70.Feldman G, Solomon C, Notaro PJ' Endodontic managementof traumatized teeth. Oral Surg Oral Med Oral Pathol1966;21:100-112.

. Steiner JC, Van Hassel HJ: Experimental root apesillcation inprimates. Oral Surg Oral Med Oral Pathol 197];37:409-415.

. Schroder U, Granath LE: Early reaction of intact human teethto calcium hydroxide following experimental pulpotomy andits significance to the development of a hard ussue barrier.Odontol Rev 1971;22:379-395.Tronstad L, Andreasen JO, Hasselgren G, et al: pH changesin dental tissues after root canal filling with calcium hydroxide.J Endod \9?.\:l.il-2\.Javelet J, forabinejad M, Baklaijd LK: Comparison of two

pH levels for the induction of apical barriers in inimalure (eelhof monkeys. J Endod l985;ll:375-378.

K6. ViiesG: Lysosoniesand cellular physiology of bone résorption,in Dingles JI, Fell HE |eds): Lyso.mmes in Biologv imd Pa-thology, vol 1, AmsEerdam. North Holland Pubi Co, 1969, pp216-253.

87. Bourne HG: Phosphatase and ealcillCLilion, in Bourne HG(ed¡: The Biochemistry and Physiology o/ Bone New York,

Aeadeniic Press, 1972, pp 79-120.

8K. Yesilsoy C, Koren LZ, Morse DR, et al: A comparative tissuetoxicity evaltiation of estabiished and newer root eanai sealers.Oral Surg Oral Med Oral Pathol 1988:65:459-467.

89. Stamos DG, Haasch GC. Gerstein H: The pH of local anes-[ he tic/calcium hydroxide solutions. / Ejidod 19S5;I1:264-265.

90. Mitchell DF, Shankwalker GB: Osteogenie potential of cal-cium hydroxide and other materials in soft tissue and bonewounds. J Dent Res 1958:37:1157-1163.

91. Binnie WH, Mitchell DF: Induced calcification in the subder-niLiI tissue of the rat. ./ Dent Re.-r I973;52:1O87-IC91.

92. McCormiek JH. Weine FS, Maggio JD: Tissue pH of devel-oping periapieal IESJOOS in dogs. / Endod 1983;9:47-51.

93. Van Hassel H, Natkiii E: Induction of root end closure, y Dc/jfCiiiW!970;37:57-59.

94. Frank AL: Endodontic endosseous implants and the treatmentof the wide open apex. Dent Clin North Am 1967:11:675-7(10.

95. Nyborg H: A survey of the problems of pulpotomy. Ret- Beig.Med Dent 1959:14:111-115.

96. Yoshida J: Sttidy on pulp healing following ptilpotomy withcalcium hydroxide. J Osaka Dem Univ 1959;4:525-530.

97. Sciaky I, Pisante S: Localization of calcium placed over am-pjtated pulps in dogs" teeth. J Dem Res 196O;39;l 128-1132.

98. Nevins AJ. Finkelstein F, Horden BG, et al: Fonnation ofmineralized scar tissue induced by implants containing colla-gen-calcium phosphate gel. J Endod 1975;1:3C3-3O9.

99. Nevins AJ, Fiukelstein F, Borden BG, et al: Revi tali îati on ofpulpless open apex teeth in rhesus monkeys using coll agen-calcium phosphate gel. / Endoi! 1976;2:I59-165.

10(1. Nevins AJ, Wrobe! W, Vaiachovic R, et al' Hard tisstie induc-tion inlo pulpless open apex teeth using collagen-calcium phos-phate gtVJ Endod 1977;3:43H33.

101. Nevins AJ, Finkelstein F, Laporta R, et al: Induction of hardtissue into palpless open-apex leeth using col lagen-calciumphosphate gel. / Endod 1978;4:76-B1.

102. Donlon WC: Immune neutrality of calf skin collagen gel usedto stimulate revitalization in pulpless open apex teeth of rhesusmonkeys. J Dent Res 1977:56:67o 673.

103. Heuer MA' An open question. ADA News 1977:8(8):2.

104. Driskell TD, Hassler CR. Tennery VJ, MeCoy LR, Clark W:Calcium phosphate resorbable ceramics: a potential alternativeto bone grafting. J Dent Res 1973;52(special issue]:123 {abstrNo. 259).

105. Bhaskar SN, Brady JM, Getter L, et al: Biodegradable ceramicimplants in bone: electron and light microscopic analysis. OralSurg Oral Med Oral Palhol 197];32:336-345.

106. Koenigs JF, Heller AL, Brilliant JD, et af Induced apical clo-sure of permanent teeth in adult primates using a resorbableform of tricalcium phosphate ceramic. J Endod 1975;1:102-106.

107. Roberts SC Jr, Brilliant JD: Tricalcium phosphate as an ad-junct to apical closure in pulpless pertiianenc teeth. J Endod1975;1:263-269.

lOK. Coviello J, Brilliant JD: A preliminary clinical study on the

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use of triciilciuni phosphale as an apical barrier. J Endod1975:5:6-1?.

109. Dimashkieh MR: The problem of the open apex - a new ap-proach: oxidized regenerated celltilose lechniqite. J Br EndodSac 1977;1O:9-I6.

110. Rossmeisl R, Reader A, Melfi R, et al: A sludy of ñ-eeze-dried(lyophilized) cortical bone used as an apical barrier in adulimonkey teeth. J Endod 1982:8:219-226.

111. Rossmei.sl R, Reader A, Melfl R, et al: A study of free/.E-drieddentin used as an apical barrier in adult monkey teeth. OrulSurg Oral Med Oral Ptilhol I9R2;53:3O3-31O.

112. Chalmers J: Transplantation immunity in bone homografting.J Bone Joiit! Smg 1959:41:160-179.

113. Burwell RG. Studies in transplantation of bone: ihe capacityor Tresh and treated homogiafts of bone to evoke transplan-tation immunity. J Bone Joinl Siirg 1963:45:386-401.

114. Gollmer L: The use of dentin debris as a root canal filling Im/OrMod 1937:23:101-102.

115. Tronstad L: Tissue reactions following apica) plugging of the

root canal with dentin chip.i in monkey leelli subji-'t le'J to pulp-ectomy. Oral Surg Oral Med Oral Palliol ¡97tí:45:297-3Ü4.

116. Claylon RJ: The Periapical Tissue Response lo and ihe SealingAhilily of Apically Packed Denlin Shamigs. thesis. Chicago,Loyola Univcrsily, May 1973.

117. Oswald RJ, Friedman CE: Periapical response lo dentin fill-ing.s. Oral Sura Oral Med Oral Palhot 1980:49:344-355.

118. WeisenseeIJA Jr. Hicks ML. Pelleu GBJr: Calcium hydroxideas an apical barrier. J Endod 1987:13:1-5.

119 Frank AL: Calcium hydroxide: Ihe ultimate medication. Demdin Norlh Am 1979;23:ö9l-703.

120. Cvek M: Clinical procedures promoting apical closure andarrest of external rool lesorption in non-vital permanent in-cisors, in Grossman L (ed): Tran.saclion.'s of the Fiflh inlerna-linnat Conference an Endodomies. Philadelphia, LJniversily ofPennsylvania Press, 1973, pp 30-44.

121. Morse DR: One-visit endodontics. Hatiaii Dcnl J 1987:I8(ll):12-i4. G

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