Endodontics

Evaluation of the apical sealing ability of apatite root canal sealerRahmat A. Barkhordar* / Marvin M. Stark** / Kenneth Soelberg**

The apical sealing ability of a tricalcium phosphate sealer was compared with that ofthree other sealers. Seventy roots of human incisors were cleansed and shaped andrandomly assigned to one of .seven gtmtps of ten roots each. The root canal systemswere obturated with gutta-percha and one sealer using the lateral-vertical condensationtechnique. The canal was sealed with Roth's .sealer, Sealapex, Kerr root canal .^aler,or Sankin apatite root sealer (Type I, ¡I, or ¡II). One grotip was filled with gutta-perchawithotit sealer to serve as a control. After the roots were immersed in silver nitrate, thedegree of dye penetration was meastired tender a dissecting microscope. Resultsindicated that Sealapex had the best seating ability, followed hy Sankin apatite rootsealer, Type IL Roth's cement showed the most dye penetration. Canals that wereobturated without sealer showed significantiy greater apical leakage.(Quintessence Int 1992;23:515-5}8.)

Introdnction

Sohd core filling material, such as gutta-percha, hasbeen used to obturate the root canai in conjunctionwith a sealer. The objective is total obliteration of theroot canal system and prevention of the ingress andaccumulation of irritants that could cause biologicbreakdown of the attachment apparatus.

Dow and Ingle' suggested that failures in endodontictherapy may be due to poor obturation of root canals.Since then, many different obturation techniques andmaterials have been introduced to increase the qualityof the apical seal.

Recently, several bone implant materials composedof hydroxylapatite (HA) and related tricalcium phos-phates (TCP) have been promoted for use in restoringosseous defects associated with periodontal disease.""'

* Associate Professor, Department of Restorative Dentistry,University of California, San Francisco, Sehool of Dentistry,7t)7 Parnassus Aven ne. Room D-3252, San Francisco, California94143-075S.

" Professor. Department of Restorative Dentistry, university ofCalifornia, San Franciseo.

These materials have also been advocated for apexifi-cation'''* and enhancement of bone fill after periapicalsurgical procedures.' Both HA and TCP appear to bebio compatible, since they do not produce an inflam-matory or immune response when placed in contactwith bone or soft tissue.'"^ Calcium phosphate bio-materials have been reported to be effective in healingmechanical perforations of the pulp chamber floor,^apical closure,"* and pulp capping." ' '

Krell and Webel" reported that, under scanningelectron microscopic analysis, calcium phosphate ce-ment (CPC) appears to be similar to Grossman's cementin adherence to the root canal wall. Chohayeb et al,'''in animai studies, showed that CPC has a uniform andtight adaptation to the dentinai surfaces of the pulpchamber and root canal walls. Krell and Madison'reported that CPC permits greater dye penetrationthan does Grossman's cement.

The purpose of this study was to compare the apicalseal produced by apatite root sealers with that achievedby calcium hydroxide sealers.

Method and materials

Seventy recently extracted human maxillary anteriorteeth were obtained and stored in 10% formalin. They

Ouintessence internationai Voiume 23, Number 7/1992 515

Endodontics

Table 1 Mean apical leakage into the canals(n = 10 per group)

Group

Roth's sealerSeal apexKerr sealerApatite Type IApatite Type 11Apatite Type IIIControl (no sealer)

Mean (mm)

1.23Ü0.3311.2000.731Ü.5900.8702.840

SU

0.3360.1700.2400,4400.2070.1710,668

were radiographed to confirm root canal patency, clo-sure of the apex, and absence of fraeture. The teethwere immersed in 2.6% sodium hypochlorite for 1 weekto remove soft tissue from the root surfaces. TTie clinicalcrown was removed at the cementoenamel junctionwith a high-speed fissure bur. The root canai systemwas cleansed and shaped to the apical foramen to a25 K file. The rest of each canal was flared by the step-back fihng technique to a size-60 file."' The eanalwas irrigated with a 2.6% solution of sodium hypo-chlorite before cleansing and after use of each file. Allroots were then stored in distilled water. The root canalwas obturated with gutta-percha (Mynol Cbemieal Co)and one of the sealers using lateral-vertical condensationtechnique.

Groups !, II, III, IV, V, and VI consisted of roots inwhich the canal was sealed with Roth's sealer (RothDrug Co), Sealapex (Kerr/Sybron Corp), Kerr rootcanal sealer (Kerr/Sybron Corp), apafite root sealerType 1, apatite root sealerType II, or apatite root sealerType III (Sankin Industry Co), respectively. GroupVII was filled with gutta-percha and without sealer toserve as a control. The access opening was filled withamalgam.

Each tooth was placed in a capped vial eontaining2 X 2-inch gauze pads saturated with distilled water,and the sealer was allowed to set at 37 °C in thehumidor for 48 hours. The root, except for the apical2 mm, was coated with two layers of clear varnish.The root was immersed in a 50% by weight aqueoussilver nitrate solution in the absence of light for 6hours. The tooth was rinsed for 1 minute in distilledwater before the specimen was exposed to fluorescentlight. The specimen was immersed in a photodevelop-ing solution for 2 hours. The root was sectioned

longitudinally, and the degree of dye penetration wasmeasured under a dissecting microscope with a digitalruler.

A Student-Ncwman-Kculs test was performed onthe means to determine statistical differences amongthe groups.

Results

The mean values and standard deviations of the meas-urement of dye penetration in all groups are shown inTable 1. Examples of the extent of dye penetration inapafite-sealed and control canals are shown in Figs 1and 2, respectively. Results of the Student-Newman-Keuls test are presented in Table 2. The test showedno statistieally significant difference between dye pen-etrafion with apatite root eanal sealers and that withSealapex sealer. No statistically significant differencewas found among apatite root canal sealers. Canals thatwere obturated with gutta-pereha and without sealershowed significantly greater apical leakage {P < ,05),

Discussion

Root canal sealers that could stimulate the depositionof hard tissue at the root apex, forming a biologic seal,would be beneficial in root canal therapy. From abiologic point of view, the ideal response of periapicaltissue after root canal treatment would be a closure ofthe apical foramen by hard tissue. To reach this objec-tive, a root canal sealer eontaining ealcium has beendeveloped.

Hydroxylapatite and TCP ceramic implant materialshave been advocated for osseous reconstruction proce-dures, alveolar ridge augmentation,'' pocket reduction,and bone fill in periodontal therapy,-^ as well as foracceleration of healing of endodontic lesions,' Apatiteroot canal sealer is a root canal obturafion materialthat utilizes tricalcium phosphate and hydroxylapafiteand has superior affinity with biologic tissue. Apatiteroot sealer Type I is a combination of TCP and HA,Radiographicaily, it responds similarly to a naturaltooth. This sealer does not have antibacterial activity.Apatite root sealer Type II contains 30% iodoformand is easily observable in radiographs. Apatite rootsealerType fll contains 5% iodcifomi and basic bismuthcarbonate to enhance its radiographie property,

Cruninger et al'*' reported that CPC is biocompatiblein animals. Therefore, extrusion of this material toperiapical tissue should nut produce an inflammatoryresponse, A tricalcium phosphate and hydroxylapatite

516 Quintessence International Volume 23, Number 7/t992

Endodonties

Fig 1 Root canal filled with gutta-percha points in conjunc-tion with apatite root sealer, (arrow) Dye penetration.

Fig 2 A root canal filled with gutta-percha without sealer(arrow) Dye penetration.

Table 2 Statistical differenees among groups

Not significant Significant (P < .05)

IIvsVIIIvsVIIVvsV,VIVvsVI

IvsIl,IV,V,VIIIIvsIII.IV,VI,Vninvsiv,v.viiIVvsVIIVvsVIIVIvsVII

compound has been shown to provide the best dentino-genic effect in primary teeth," Collagen-calcium phos-phate gel appears to be capable of inducing revitaliza-tion of pulpless open-apex teeth,""

The silver staining method was selected as a stainingprocedure because of the strong optical contrast ofsilver particles. Silver staining produces a much sharperpicture of dye penetration and therefore is measuredeasily. Because silver ions precipitate into fine partieles,no further diffusion of these particles is likely,"'

The present results demonstrated that the calciumhydroxide-containing sealer had the best sealing prop-erty, which is in agreement with our previous finding, ^Apatite root canal sealer had minimal dye penetra-tion, and no statistically significant difference wasfound between Sealapex and apatite sealer. Roth's ee-

ment showed the most dye penetration. A significantdifference was found between Sealapex and Kerr rootcanal sealer. Canals obturated with gutta-percha andno sealer had significantly more dye penetration thandid any other group. These flndings support the re-commendation to use a root canal sealer with sohdcore filling materials.

References

t, Dow PR. Ingle Jl: Isotope deleritiination of root canal fail-ures. Oral Surg Orol Med Oral Pathoi 1955 ;8:1100-1104.

2. Bhaskar SN, Cutrighl DE. Knapp MJ, el al; Tissue reactionto intrabany ceramic impianls. Oral .Surg Orai Med OralPathoi t971;31:282-289.

3. Driskell TD, Hassler CR,Tennery VJ, ci al: Calcium pliospliateresorbabie ceramics: a potential allernative to bone grafting,J Deni Res 1973;52:I23 (abstr No. 259).

4. Nery EB, Lyncli KL: Preliminary clinical studies of bioceramicin periodontal osseous defeets, J Feriodomol 1978;49:523-527.

5. Heller AL, Koenigs SJE, Brilliant JD, et al: Direct pulp cappingof permaneni teeth in priirates using a resorbabie form oftricalcium phosphate ceramic, J Endod 1975;I:95-1OL

6. Coviello J. BriUian JD: A preliminary clinical study on theuse of tricalcium phusphatc as an apical barrier. J Endod1979;5:6-]3.

7. Howdcii GF: Biodegradable ceramic (Sytithob) in humatiendodontic surgery. J Br Endod Soc 1977;10:71-76.

8. Cohen DW (ed): Symposium on a new bone.grafting implantmaterial for the treatment of periodontal disease. CompendConlin Educ Dent I9S2,3 (Jan-Feb suppl).

Quintessence International Volume 23, Number 7/1992 517

Endodontics

y. Himel T. Brady J, Weir J: Evaluation ot repair of mecliaiiicalpi;rforations oC the pulp i-hambcr Hour using biodegradabletricalcium piiosphalc or calcium hydroxide. J Endod1985;1I:161-1&5.

10. Roberts SC Jr. Brilliant JD: Triealciuin phosphate a an aJ-juncl LO apical chisiiro in pulplcss pormaiicnt (celh. J Endod1975; 1:263-269.

11. Heys DR, Cox CF, Heys RJ, ct al: Histological consider.,ations of direct pulp capping agents. J Dem Res 1981 ;60:1371-1379.

12. Schroeder A. Slich H. Reveh J: Reaktion der gesunden,Jugendlielien Affcnzahnpulpa auf einen Bioïement. SchweizMonaisschr Zahnheilkd 1TO2;92:5ÍÍI-5S5.

13. Krell KF, Webel JS: A calcium phosphate cément root canalsealer—scanning electron microscopic analysis. ./ Endod1984; 10:571-576.

14. Cbohayeb AA, Latry CCTsakmi^ PJ. Evaluation ol caleiumhydroxide phosphate as a rool canal sealer-filler material.J Endod 1987;t3:3S4-3S7.

15. Krcll KV, Madison S: Comparison of apical leakage in leelhobturated with a calcium phosphate cement and Grossman'scement using lateral condensation. / Endod l9S5;ll:336-339.

16. Weine FS: Endodontic Therapy, ed 3. St Louis. CV MosbyCo, 1982. pp 283-286.

17. Drobeck HP. Rothstein SS. Gumaer Kl, et al: Histologieassessment of soft tissue responses to implanted multifacetedparticles and discs of bydroxylapatile. ./ Oral Maxillofac Surg1984;42:143-149.

18. Gtuninger SE. Siew C, Chow LC. et al: hvaliiation of thebiocompatibility of a new ealeium phosphate setting cement./ Dem Res 1984;63:200 (abstr No. 270].

19. Jean A, Kerebel B, Kerehel LM. et al: Effects of variouscalcium phosphate biomaterials on reparative dentin bridgeformation. ] Endod 1988; 14:83-87.

20. Nsvins AJ, Finkelslein F. Borden B. et al: Revitalization ofpulpiess open apes teeth in rhesus monkeys, using collagen-ealeium phosphate gel. J Endod 1976:2:159-165.

21. Wu W, Cobb E, Dermann K: Detecting tnargin leakage ofdental composite restorations. J Biomed Mater Res 19S3;17:37-43.

22. Barkhordar RA, Bui T, Watanabe L: An evaluation of sealingabilily of calcium hydroxide sealers. Oral Surg Oral Med OralPüí/i«n989;68:88-92. D

t se N 086715-233-0;147pp;21 ittus;USS3a

Geriatrie Dentistry inEastern EuropeanCountries

Edited byWulter Künxel

Divided into four parts:1. Clitiical aspects2. Psychosocial aspects3. Regional epidemiological

data4. Recommendalions

Insight into how easternEuropean countries arefacing issues of geriatricdentistry.

CALL OR FAX T O O R D E R : Ttl: (SOO) 621-0387 nr(708) 682-32Ï3; Fax: (708| 682-3288

or fill out (he oiJer form and bend to:Quintfr' sencv Publish i nj; Cii. Inc5SI N. Kiml,ert> DriveC il rill Stream, IL 60188-1881

ISBN 085715-228-1;262 pp; 32 ¡Hus; US Î20

Dentistry in (he 21stCentury: A GlobalPerspective

Edited byRichard J. Simonsen

Espefts irom all overthe world discuss thestate of dentistry at theend of the 20th centuryand project prospectsof the profession intothe 2Ist century.

518

1. L-opies cif (2230) Geriatric Dentistry in 'Eastern European Countries at US S32/copy and/or

copies oí (2281 ) Denliïtr} in the 21st Century:A Global Perspective ;it VS $2ü/copy.

Zip

lelephoLic

1 1 General Practitioner I I Specialist.I i Bill me, including shipping & handlingI I Charge to my credit card plus shipping & handling¡ I Visa/MaslerCard I I American Express

Eiipires

Signature,

chars« » i l l beaddeO to all Orders. For Illinois and Canalian. la let la . will bcmkfcil if applicable. Paymsni iiiu>L be madf i

I