A comparison of apical seal: Chloroform versus eucalyptol-dipped gutta-percha obturation

A comparison of apical seal: Chloroform versus eucalyptol-dipped gutta-percha obturation

0099-2399189; i 506-0257,$02 C0/0 JOURe~kt O+ ES.')(X.)(~%TIC".; COpytKJh, ': 1989 by The American Assooa,,on o' Erx:lo(Jo~t~sts Pr~n~.eq m U S A V(...

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0099-2399189; i 506-0257,$02 C0/0 JOURe~kt O+ ES.')(X.)(~%TIC".; COpytKJh, ': 1989 by The American Assooa,,on o' Erx:lo(Jo~t~sts

Pr~n~.eq m U S A

V( )t

15. N::

6, Ju,,l- 1989

A Comparison of Apical Seal: Chloroform versus Eucalyptol-dipped Gutta-percha Obturation Peter P. Yancich, DDS, Gary R. Hartwell, DDS, MS, FICD, FACD, and Frank R. Portell, DDS, MS, FAGD

Three groups of extracted teeth were obturated using gutta-percha and lateral condensation. In one group the gutta-percha was dipped in chloroform before condensation. In a second a eucalyptol dip was used. No dip was used in the third group. A dye penetration study was done to compare leakage among the three groups. The teeth were cleared for viewing and measurements of dye penetration were made using a stereomicroscope. Statistical analysis using Kruskal-Wallis one-way analysis of variance of the results showed no significant difference among test groups at the 0.05 level.

because it can be used to ~fften gutta-percha ~hile exhibiting lens h~:al tissue toxicity than chloroform (4. 7). lhereforc, it might Im better to use eucalyplol instead of dlloroform t'c~r tho.~ who prefer tile dip technique It) obtt, ratc tile rtx)t canal space. "Io date. no leakage studies have been relx)rled that compare the dip technique using each of ttu..'se m h e n t s . The purlx~se of lllis stud~ was to compare the apical .~'al obtained using either chlorotbrm- or eucal.~ptt~l-dipl'~'d gulla-lx.'rcha for obluration and It) determine whether either melht~l was superior ~ith regard It) leakage. %IAI'ERIAI.N A N D M E ' I ' I I O I ) S lqfl,,-tv, o human single-rr215 teeth were collected mlmcdiatel.~ follo~ving extraction and stored in I0~; formalin sa}lution. None of tilt" teeth had a root curxature of more than 20 degrees from the axial plane. All had Weine's (3) ('laxs I root canal configuration as ~ie~ed radiographically from the mcsial aspect. Prior Io canal prepan, tion. all teeth ~erc placed into a v.)lution of 5.25"; st~.lium h.~ ix~.'hlorite {('lorox ('orp.. ()akland. ( ' A ) It) remo~c an} tissue tags attached to the rt•

'lhe imlx~rtance of attaining as complete a ~'al as ~)ssible of the root canal system is x~ell recognized. Nearl~ 60"; of all endt~hmtic failures are cau~*d b.~ incomplete ohturation of the root canal space I 1, 2). According to \Veine (3). the most c o m m o n t a u t " o l e n d o d o n t i c failure is lack of adequate apical ~'al. l h e object of ohturation ix to seal tile entire r~)t canal space. It is oh,. ious thai a preparation prt• by a tile ~ ith a Ix~inted tip rlla) gouge the walls and prtxluce an eccentric shaw. making it dillicult to .~'al the apical ix)rtion of the rt~)t canal space ~ ith a round, smt~th-surfaced, blunt-tiplx'd master guttair~..'rcha cone. l h e ideal answer would I~,."Io make an impression of the apical ix~rtion of the root canal and then fabricate a master cone to conform to thai impression, lhis ix ix)ssible clinicall), by softening the gutla-l'mrcha with a .~)b, ent It) obtain a replication of the apical root canal preparation 13). ."~.'veral in~cstiga,tors (4. 5-S)advt~-alc lhc use o f a master gulta-lx'rcha ctme fitted slighll.~ short, diplX:d in a surface.~)fiening ~ l u t i o n . and seated in the rt,)t canal to obtain a direct impression to e n h a n c e a tight lit in the apical region. ('hlorofoml and eucal~ptol are t~vo s o h e n t s that hi,~e ~.'en suggt~ted for such u~'. l:lolh of these agents v, erc used ~,,ilh gutta-l'~'rcha as early as I g SO I t)). ( ' h l o r o f o r m has been the nlosl popular nlclhtK| o f s o f l e n m g gutta-tx'rcha It) enhance apical tit. I h)~.~,ex er. in~ cstigations by the l.'ot• and Drug Administration ha~e suggested that chloroform n)a.~ Ix" a potentn, l carcinogen (10). Ihe applicahilil.~


tTsing high-slX:cd huts and waler spra~ the cro~ ns of i, ll teeth ~ere removed at the c e m e n m enamel junction. After pulp removal with a harl~d broach ( l ' n i o n Broach ('orp.. l.ong Isk, nd ('it.~. NY}. a u l 0 K lile (S.~hron/Kerr l>,.'ntal Prt~lucts l)iv.. Romulus..~,II) v, as inlrtxh,ced until it could I x . . ~ e n at the apical forl, men. The ~orking length ~ere determined by subtracting 1 m m from the actual nx)t canal length. In order to minimize extx.-rimental varii, hles m tile canal preparation pha~', all of the subsequent procedures were performed h~ a single Ol~'rator. \Vith the use of a step-back preparation technique, the canals were prepared It} a , a 0 K lile at the working length and then the coronal lx)rlior! of the canal ~i,.s flared. "Io ensure palenc.~ of the apical foramcn a =10 K file was pas~'d through the apical foramen after the u~" of each instrument size. Ph.~siological saline ~as used i,s the irrigating solution, l'he teeth ~ere then mndoml.\ distributed into Ix)satire controls (2 teeth), negative controls (2 teeth), and three experimental groups of 16 teeth each. l'he three eMx'rimcnlal groups ~ere a combination of lateral compaction and one of the Iollo~ ing three techniques: (a) chloroform~liplx'd gutta-lx'rcha: (hi eucal.~plol--dippcd gutta-percha: and (c) non-diplx'd gutta-percha. "lhe prepared canals ~ere obturated b~ individuals tamiliar with each of the

o f this data to c h h m ) l b r m ' s u~" in c,ld(~.lonlics has not Ix'en

established. Nevertheless. et,cal~ plol ix a ix~ssible alternative



Journal of EndodonUc

Yancich et al.

obturation techniques used in this investigation. In the chloroform dip technique (group 1) an appropriately sized master gutta-percha cone was dipped for 3 s prior to placing it into the root canal system. In the eucalyptol dip technique (group 2) (Eucalyptol N.F.; Sultan Chemists Inc., Englewood, NJ) a 25-s dip was required to adequately soften the gutta-percha so an impression of the apical portion of the root canal could be obtained. The master cone (groups 1 and 2) was removed from the canal. A thin layer of nonstaining root canal sealer (Roth Sealer, Type 801 Elite; Roth Drug Co., Chicago, IL) was used to coat the root canal wall. The prepared master cone was then coated with the same sealer and seated to place in the prepared root canal. Size B finger pluggers (Star Dental Mfg. Co., Conshohocken, PA) and #20 accessory gutta-percha cones were used to complete the lateral compaction phase. Excess obturating material was removed from the coronal portion of the root canal with warm endodontic pluggers. The coronal access was then sealed with Cavit (Premier Dental Products Co., Norristown, PA) and the root was covered with sticky wax and nail polish except for the apical foramen area. In the non-dip group (group 3), a #50 or 60 master corie was fitted 0.5 m m short of the working length. The canal wall and the master cone were then coated with sealer and lateral compaction was completed as described above. Positive control teeth were instrumented and a #45 guttapercha cone was loosely fitted in the root canal. A dry #2 cotton pellet was placed into the coronal end of the canal and the access opening sealed with Cavit. The roots of these two teeth were then covered with sticky wax and nail polish except for the apical foramen. Negative control teeth were instrumented, the access opening was sealed with Cavit, and the entire root surface and apical foramen was covered with sticky wax and nail polish. All completed teeth were stored at room temperature in 100% humidity for 2 wk. All 52 teeth were then placed into India ink (Waterproof India Ink, Steig Products, Lakewood, NJ) for 72 h at room temperature. The teeth were then removed from the ink and rinsed with tap water. The wax and nail polish were removed and the teeth were prepared for clearing by decalcifying in 5% HNO3 for 5 days, changing the acid solution daily. Teeth were then washed in running water for 10 rain and dehydrated by placement in 100% methanol for 3 days, changing the solution daily. The teeth were then placed into methyl salicylate to complete the clearing process. The materials and times selected for use in this investigation resulted from data obtained in a preliminary pilot study conducted to evaluate the dye penetration clearing technique for studying leakage. When compared with methylene blue dye, India ink was found to give more consistent results and to better resist breakdown when placed in contact with the agents used for decalcification and clearing. Seventy-two hours was found to be adequate to allow dye (ink) penetration. Several times were tested for the acid and methanol and 5 k days and 3 days, respectively, were found to be adequate. Two evaluators working independently and unaware of the groups being examined evaluated the apical seal after the teeth were cleared. Linear measurements to the nearest 0.01 m m were made from the apical terminus of the root canal filling to the maximum coronal point of ink penetration using a stereomicroscope (Wild MPS 45; Wild Heerbrugg Ltd., Heerbrugg, Switzerland) and Filar micrometer eyepiece (Bausch &

Lomb Inc., Rochester, NY) at • 12 power. The acquired dat; was then subjected to statistical analysis (Kruskal-Wallis one way analysis of variance) to determine whether there was an~ statistically significant differences among the experimenta groups. RESULTS The positive controls showed a maximum leakage of 6.16 ram. This was the greatest leakage that could be measured on the experimental groups with the Filar eyepiece. The negative controls showed no leakage. The linear measurements of the ink penetration in the various test groups are shown in Table 1. The test groups were subjected to a nonparametric KruskalWallis analysis (Table 2). The average of the rankings showed no significant difference among test groups at the 0.05 level. Interrater reliability (r) also showed no significant difference between the two raters. Within the parameters of this ink penetration study, there was no statistically significant difference in leakage among any of the three test groups. Therefore, for those clinicians who favor a dip technique to obturate the root canal space, eucalyptol would seem to be a viable alternative to chloroform. For those who do not use the dip technique, there is no apparent reason to change since neither of the dip techniques significantly sealed the canal better than the lateral compaction method. DISCUSSION A superior method of sealing the apical foramen at the cementodentinal junction creates a favorable biological environment for periapical healing to take place by sealing offany remaining irritants in the root canal system. These potential irritants include microorganisms, microbial products such as toxins and tissue breakdown products which may remain trapped in dentinal tubules, root canal fins, or areas of the root canal system not touched by root canal files (3, 4), Softening the gutta-percha master cone with a solvent to obtain an imprint of the apical portion of the canal and then using it in conjunction with root canal sealer and lateral compaction of gutta-percha is advocated by several investigators (4-8). The most commonly used solvent solution has been chloroform. Tamse et al. (11) showed that chloroform was the most effective so/vent for all brands of gutta-percha tested. Wong et al. (5) compared the replication ability of three chloroform-softened gutta-percha obturating techniques. They found no significant difference in replication, but found that chloroform-dipped fillings had less shrinkage after 2 wk than the other techniques. Keane and Harfington (12) demonstrated in an in vitro dye leakage study that a 1-s dip of a gutta-percha master cone in a chloroform followed by a lateral compaction technique, using sealer, provided as good a seal as lateral compaction with sealer and no dip. Until this present investigation, no studies have compared leakage of either laterally condensed chloroform- or eucalyptol-dipped gutta-percha obturations with lateral compacted gutta-percha with no dip. The results of this study show no

Vol. 15, No. 6, June 1989



T~m.e 1. Depth of ink penetration in millimeters Lateral Condensaton w,th No D,p


Eucalyptol D,p

Rater 1

Rater 2

1 2 3 4 5 6 7 8 9 10 11 12 13 14

1.85 1 62 6.09 0.00 t.57 t 86 O.95 1 87 0.00 1.10 0.41 ~.22 0.38 0 O0

2.35 16 0 6 16 0.00 1 52 1.83 0 83 1.86 0.00 1.14 0.35 0.98 0.37 0.00

1 2 3 4 5 6 7 8 9 10 11 12 t3 14


~ 35





0 74


Interrater rehabdfly (r)



Sample S,ze

Rank Sum

Latera! coe,densation Eucalyptol O,p Chloroform d~p

16 16 16

452.0 365.0

' ,~r;l~,*+l





9 /~, P ' ( ' . ~ 4 t b ~ t ~ = s O 4 1 ~ , ' l < . s a c r ' ~ e l c " , . ' s . ' l , t a , e ( : s l n ~ x . t c l e

~W"t:~Pc.:l*k]'7~ - R . q ! D "

Rater 1

Rat~ 2

Rater 1

Rater 2

304 0 59








2.50 616 0 49

0.60 2.62 6.16 0.50







1.34 3 57

0.00 1.17 3.37 6 16


1.34 3.52

5 6 7

100 2.61 5.02 1 29 1 55

0.00 0 00 6.16 5.17



2.62 5 10 1.30 1.52 0.00

9 10 11 12 13



6 16 5.13

15 t6

(,'4;5 a

significant difference a m o n g any o f the three techniques evaluated. The l:otxl and |)rug Adnlinistration's re|x~rt noting ehlorofi)rm to Ix" a lx)tential carcinogen has created a situation ,,,,here an acceptable substitute might IX" considered b~ those c:inicians using tile chhmfform dip teeimique (4. I(B. Inhalation of chhm)form ~,arx'~rs has been shov, n to be toxic to animals and h u m a n s (13. 14). ('hlorofi)rm does. boy, ever. offer the follov, mg advantagt~, o~er eucal,, ptol: (a) solubilizes gutta-percha more mpidl.~ than euealxptol: (b) is less exlx.'nsi~e:

3.35 6.16 6.16 0 00 0.22 0.63 6 16 0.09 0.00 000

6.16 0.00 0 20 0 61 6.t6 009 O.O0 000

0 941

T,~BLE 2. Kr~skal-Wallis one-way analysis of variance for 48 cases" (dependent vanable is depth; g r o ~ n g variable is te~hnKlue)

wll'~.'l + :),IlS

Chloroform D,p


make an apical imprint of tile canal. It has Ix'en suggested that if tile m)lution is heated in a dap[xm dish to 3(I~ ` (g6~ its .~fftenmg effi.'et on gutta-lxercha vr addititmal re~'arch in the areas of tissue toxicity and carcin()genie ~)tcntial t)t cucal.~ptol liqt, id. t h i s additional research is encouraged Ix'fore eucalxptol is %'leered for routine t,~" ill end(xhmtic obturating |mx.'edures.

('ON('I.I N I O N

It ~ o u l d aplx.'ar from tile results of this investigation that eucal',ptol nl:.l~ prove to ix" atn a,dcquate substitute for ehh>roform m softening gutta-lx.'rcha. Within tile paranleters of


Yancich et al.

Journal of Endodontics

this study, the seal obtained with the eucalyptol dip technique was equivalent to that obtained with the chloroform dip technique and lateral condensation of gutta-percha that was not dipped. Additional research into the toxicity of eucalyptol is encouraged. Commercial materials and equipment are identified in this report to specify the investigation procedures. Such identification does not imply recommendations or endorsements, or that the materials and equipment are necessarily the best available for the purpose. Furthermore, the opinions expressed herein are those of the authors and are not to be construed as those of the Department of the Army or Department of Defense. Dr. Yancich is chief, endodontics, U.S. Army Dental Activity, Fort Stewart, GA. Dr. Hartwell is the former director and Dr. Portell is a former assistant director, Endodontic Residency Program, U.S. Army Dental Activity, Fort Gordon, GA, Requests for reprints should be directed to Dr. Gary R. Hartwell, Department of Endodontics, Box 566, School of Dentistry, MCV/VCU, Richmond, VA 23298.

References 1. Dow PR, Ingle JI. Isotope determination of root canal failure. Oral Surg 1955;8:1100-4. 2. Ingle JI, Taintor JF. Endodontics. 3rd ed. Philadelphia: Lea & Febiger, 1985:36. 3. Weine FS. Endodontic therapy. 3rd ed. St. Louis: CV Mosby, 1982:19, 210, 34-50. 4. Cohen S, Burns RC. Pathways of the pulp, 3rd ed. St. Louis: CV Mosby,

1984:205-24, 246-51. 5. Wong M, Peters DD, Lorton L, Bernier WE. Comparison of gutta-percha filling technique: three chloroform-gutta-percha filling techniques, part 2. J Endodon 1982;8:4-9. 6. Christie WH, Peikoff MD. Direct impression technique. Sealing prepared apical foramen. J Can Dent Assoc 1980;43:174-80. 7. Morse D, Wilcko J. Gutta percha-euca percha. J Acad Gen Dent 1978;26:58-64, 8. Bence R. Simplified endodontics: Chloropercha technique. J Acad Gen Dent 1974;22:30-3. 9. Koch CRE. History of dental surgery, Ft. Wayne Ind Nat Art Pub Co 1910;1:184, 213-4. 10, Food and Drug Administration. Memorandum to state drug officials Washington, DC: U.S. Government Printing Office, 1974. 11. Tamse A, Unger U, Metzger Z, Rosenberg M. Gutta-percha solvents-a comparative study. J Endodon 1986;12:337-9. 12. Keane KM, Hardngton GW. The use of a chloroform-softened guttapercha master cone and its effect on the apical seal. J Endodon 1984;10:5763. 13. Chloroform (Trichlorometane) hygienic guide series. Am Ind Hyg Assoc J 1965;26:636-9. 14. Challen PKR, Hickish DE, Bedford J. Chronic chloroform intoxication, Br J Ind Med 1958;15:243-9. 15. Patel S, Wiggins J. Eucalyptus poisoning. Arch Dis Child 1980;55:4.05.06. 16. Low D, Rowal BD, Griffin WJ, Antibacterial action of essential oils. Planta Med 1974;26:184-9. 17. Maruzzella JC, Sicurella NA. AntibacterJal activity of essential oil vapors. J Am Pharm Assoc 1960;49:692-4. 18. Lysenko LV. Antiphlogistic action of eucalyptus oil azulene. PharmacoDynamics 1967;30:341-3. 19. Price WA, Report of faboratoryinvestigations on the physicalproperties of root filling material and the efficiency of root fillings for blocking infection from sterile tooth structures. J Natl Dent Assoc 1918;5:1260-80.