322 Australian Dental Journal, October, 1974

Sealing properties of some root filling materials evaluated with radioisotope

Roberto Holland

Valdir de Soura

Tufy Abdalla

and

Marty C. Russo

BssTRAcT-l'enetration of a solution of l I 3 ' was observed in witro in the apical zone of root canals of human teeth filled with zinc oxide eugenol, Rickert'y root sealer and Alpha canal paste. With thicker mixes generally less penetration using lateral Condensation compared with the thick mix and single cone or fluid mix and lateral condensation.

(Received for publication April , 1073. Revised version November, 1073)

I ntroductlon A close relation between endodontic treatment

failure and incompletely filled root canals has been demonstrated.(') (*) The presence of empty spaces between the filling material and the canal walls as one of the greatest single causes of the failures has also been menti~ned. '~)

Several investigations have been conducted in order to obtain a filling that can precisely isolate the dentinal tubules from the periapical tissues. Thus far, the sealing properties of various materials have been tested as well as their dependence upon

('1 Grossman, 1,. I.--\ stndy of temporary Allings as hermetic senling agents.

'*'Ingle, J. 1.-Root canal obtnration. J.A.D.A., 53: I , 47-55 (July) 1956.

l a ) Dow, P. K., and Ingle, 5 . 1.-Isotope determination of root canal failwe. Oral Sorg., Oral bled., and Oral Path., 8 : 10, 1100-1104 (Oct.) 1955.

('I IIlgginbotham, T. ],.-A comparative study of the physical properties ot Rve commonly wed root caiiol sealerr. Oral Surg OralMed.,andOral Path.,%: 1,89-101 (JuIy)1967.

'61 ~ e ~ s i i ? g , J. J.-AI) investigation of the sealing properties of some root fllling materials. J. Nrit. Endodont. SOC., 4 : 18-22 (Summer) 1QiO.

'0 Zerlotti, I.:.-Estudo iu witro das propriedarles dns pastas e cimendos obturadores de condutos radiculares. Rev. Ass. Paul. Cirurg. Dent., 1 3 : 5, 275-277 (Oct.) 1959.

J. D. Kes., 18 : 2. 6 i -71 (Feb.) 1939.

some factors, such as the technique of condensa- t i ~ n , ' ~ ) ( 6 ) and the composition of the sealer.6) But information is lacking with regard to other individual variants, as well as of an interaction between them, and this oan only be obtained through methods which have a high degree of 8COuraCy.

Radioisotope infiltration may be employed as an aoourate method for testing the ability of different fillings to seal the canals. This study wes designed to compare the sealing quality of a number of root canal pastes, by using the I's1 as tracer, under variations of the physical form of the sealers and also of the condensation technique.

Materials and methods Two hundred and ten extracted human teeth

were collected. Before being used, the teeth were washed and stored in distilled water that was renewed every 24 hours. To simplify the mechanical treatment of the radicular canals, the crowns were cut away with carbodundum disks. The canals

Australian Dental Journal, October, 1974 323

were oonsidered completely enlarged with a size 0 file passed through the apiml foramen freely. Then, after a new bath in distilled water, the roots were dried with absorbent paper and a layer of neil varnish was applied to all their external surfaoes, but the opening of the oanals was sealed with gutta- pemha points ; after which they were wrapped in tinfoil and the pieoes received another layer of nail varnish. In this manner penetration of the redio- isotope was prevented other than by the opening of the oanals.

After the removal of the protective gutta-percha points, the radioalar canals were filled with the following pastes :

(1) Pyocidina* Powder :

Zino oxide . . .. .. 10.0 g Trioxymethylene . . .. 0 - 4 0 g Sulfanilamide .. .. 2.0 g Barium sulphate . . .. 10.0 g Alum .. .. . . 0.1og

Liquid : Beeohmood oreosote . . .. 7.6 ml Neutral glyoerin . . .. 2 - 6 ml Formaldehyde . . .. 0.0 ml Methyl salioylate . . .. 0.6 ml Sulfanilamide .. .. 0.6 ml

Powder-liquid ratios : 176 mg-0.08 ml ; 176 mg- 0.06 ml.

(2) Alphacanalt Powder :

Zino oxide tolubalsamized . . Zino oxide (Ph. brasileira) . . Thymol . . .. .. 2 - 6 g Chloral hydrate . . .. 2 - 6 g Tolu balsam . . .. .. 2 g Aoetone . . .. .. l o g

8Og 90 g

Liquid :

Powder-liquid ratios : 176 mg-0.116 ml ; 176 mg-0.076 ml.

(3) Zino oxide and eugenoll:

176 mg-0.056 ml. Powder-liquid ratio : 176 mg-0-096 ml ;

(4) Waoh's paste. prepared aacording to McElroy[') Powder-liquid ratio : 176 mg-0.16 ml ;

176 mg-0.066 ml.

* Andrare and Filhos, Ltd.

t Laboratbrio Mercex Ltd.

: 9. s. white.

1'' McElroy, D. L-Physical materials. J.A.D.A., 50 :

properties 4, ,433-440

of root canal (April) 1955.

Rlling

( 6 ) Riokert's pastee Powder-liquid ratio : 176 mg-0.04 ml ;

All the tested pastes were used in two different eonsistenoies and the radioular canals were filled aaoording to the single gutta-peroha cone teohnique or that of lateral condensation.

The distribution of the filling teohniquee, the tested pastes and their powder-liquid proportions, aooording to the different experimental groups of teeth, was as follows :

Of the 200 root canals filled, lateral oondensation of the gutta-percha was used in 100 end a single cone in the remaining 100. Each sealer was mixed with its liquid in two oonsistencies as indicated in the powder-liquid ratios so that eaah sealer was applied to 40 root canals.

Immediately after filling, the roots were immersed in solution adjusted to oontain 7 mo/ml and maintained at 37" C. Roots whose canals were not filled were used as controls and also immersed in the tracer solution. After 24 hours, all the teeth were washed and embedded in self-ouring aarylio resin. The blooks obtained were ground according to the longitudinal axes of the teeth until their sagittal plane was remhed. The hemi-seations were numbered from 1 to 210 and the flat side of emh hemi-seetion was placed in tight contaat with dental X-ray film in the dark room. The exposure time for these survey autograms was 24 hour8, followed by short intensification by X-rays.'8'

The autoradiograms were projected with 36 magnifications and the areas of infiltration oould be drawn. The extension of the infiltration areas in centimetres was measured with a pachymetre.

Analysis of these results shows that there is a significant intermtion between the physical form of the paste and the oondensation teohnique, as well as between the condensation teahnique and the oomposition of the material ( p = O . O l ) . Then, are also significant differenoes according to the con- densation teohnique and the kind of compound. Three examples am shown in Fig. 1, 2, 3.

176 mg-0.026 ml.

Rerultr The averages of the measurements corrosponding

to the degrees of radioactive iodide (P1) penetration are expressed in Table 1.

It will be noted that greater infiltration has occurred with single-aone technique when used with the Alphacanal paste and that thicker consistency has reduced the infiltration when lateral oon-

- 5 Ken Manufacturing Co.

In' Russo M.-Metodo para avtlliayao qoantltativn do8 resu!tados da inflltraqao niarginnl de radioishtopo 131-INa em restaarayoes dentnis. Rev. 13rasil Odmt.. 25 : 153. 295-302 (Seut.-Ort.) 1968.

324 Australian Dental Journal, October, 1974

Fig. 1.-Alphacanal paste. Thick mix and lateral condensation (a), fluid mix and lateral condensation (b), thick mix and single cone (r), and fluid mix and single cone (d).

Fig. 2.--Zinc oxide-eugenoi paste. Thick mix and lateral condensation (a), thick mix and single cone (h), and fluid mix and single cone (c).

Fig. 3.-Rickert’s root sealer. Thick mix and lateral condensation (a), thick mix and single cone (b), and fluid mix and lateral condensation (c).

densation was employed (Fig. 1). With zinc oxide Discussion eugenol paste tho great,est infiltration occurred The rcsults havc shown significant differenon with the thin consistency and single cone (Fig. 2). in the infiltration depth values verified with the Similarly, with Rickert’s sealer there is more various past,es. On the othor hand, Marshall and infiltration with t.he thinner consistency and Mar~ler,‘~’ after studying the sealing property of single cone technique (Fig. 3). ~-

I n all the roots used as the control group, intense I ” ) Marsliall, F. J.. and Masslrr, lI.-SraIing of piiiplras teeth J. n. & l i d , 16 : 4, li?-184 rralualcrl w i t t i r;idioiwto]i~~.

(Ort.) 1961. radioisotope penetration %as verified.

Austral ian Dental Journa l . October, I974 325

TABLE 1 Averoge degree of rrrtbiorcctive aodide penetration as mensured on the ~rvtorcrtliogrrlrr~a of 200 $lid root cnrlols

~~

1'yi)ciclinn IVach

c, 1 ('?

5 . 9 1 5 . 8

B,==Paste with lesser powlor propnrtion. B2 =T'nate with grcatrr p.xvdirr proportion. C',= Latoral conrliirisat inn. C, ~ S i n g l c cono.

somo sralrrs, have roportc(1 thrrt tho sonlors to*itr(l wcro only slightly different in efficiency. This appnrrnt clivrrgoncy in resrilts may bo explained by consicloring tha t in this papor a mnro accurate n i c ~ t h o i l WRJ iiwd for obtaining antl ovaliintiny tho r<!nidts ant1 also tha t othor veriahlos wcro introtlucrtl. A s tho intoraction botwoon composition of tlio

s c d c r antl contli?nsnt ion tcchniqito was significant, the offoot of tho pasto alono may bo doponclont ontirely on tho condensation techriique. But tho ilifforcmt consixtoncicts of the parle alone did not Imxliire any significant tlifforencns in the infiltration. It would soeni that the consistoncy of tho pasto, togcthor \vith tho composition of the pado , has a significant influonco on tho results, antl further that, tho coiitlensation tcwhniquo is the moro irnpor tan t .

Altorations in tho powlor-liquid proportion nlso introtluco alterations of some physical properties, AS has btwn ob~erv-ntl by various authors. Thus fzrr, there woro rolatrtl variations in solubilit,y and iliaintograt inn,'LU) as \roll as in maw tlimnnsion and iiifiltration,(l'~ of diffrrcnt root canal sralrrs.

Iliclirrt :\ Ipllncannl

prrsontotl in this papor aro conccmletl with tho infiltrations that occur immctliirtoly aftttr tho root canals wero filled. Accoriliiig to somo authors, tho mais marginal infiltration is grvntvr whon i t i* vorifictl soon after tho material ~ n a i i i ~ ~ i i l t r t i ~ ~ r r . ~ ~ ~ I'ostrrior tlrcrraw in infiltration rxtvnsiim cortltl I ~ t r

cxplainrtl by tho incrraso i n thr: matorial l i idli . i ' l i lir1

.Auothoi. variable that must bo nicntionotl BH D cawo for somo tlivergoncios is tha t rcrprcwntocl by tho oporator. Marshall am\ Jla~slor,(~' aftor consi(lrring this vtwinblo: hnvo ohsorvotl groat chfingos iIopi*n~ling upon it.

Difforont con~lensation tochnique3 alw dctcrmino highly significant tlifforoncrs in tho infiltration clopth valrirs. Vaiious authors"' '51 have rolatctl hotter rosults when tho lateral conilennatioii tech- nique wa.3 employod. Nevortholess, according to our rosults. since tho pwte coinpositio~i ant1 con- densation technique aucl tho paste consiatenay ant1 condensation technique intoractionr are also highly significant, tho condensation result consitlorod nlono may be clcprmlont on the othor two factors. I t is

proposotl to oxtcn(l tho observations on tho renct ions in ortlcr t o dotermino i f antl mlrcri stnhilizat i o i i

occurs.

Faculdade de Odontologia,

Sgo Paulo, B r e d Araapat uba,