endodontics MILTON
SISKIN, D.D.S.
College of Dentistry The University of Tennessee 847 Monroe Avenue Memphis, Tennessee38163
Endodontic morphology IV. A comparative
Regimld
study
IIT. Hessim, D.D.Xc., X.D.S., P.R.A.C.D.S.,
Syd?ley, dm+rnlia
One hundred sixty-four extracted human teeth were infused under vacuum mith a radiopaque contrast medium and studied radiographically after the preparation of their root canal systems with endodontic instruments for obturation by the lateral condensation technique. A comparison was made with radiographs taken of the same infused specimens prior to instrumentation, together with the data recorded during instrumentation. The over-all success rate of canal entry and adequate preparation was high (92.0 per cent) ; it was highest in maxillary incisors and canines (100 per cent) and lowest in mandibular incisors and canines (81.8 per cent). The SUWPSS rate in maxillary and mandibular molars was 92.1 per cent.
W
hen the condition of the pulp or the periapical tissues necessitates endo1--. ..~ 1--~L ~~~~ ~~~L1~ l-:l:L-- -2 Ll.. A-.. A:^ L-^..A_^_^ L AL. -..^_..__ 1. :- I-.~...,
METHOD
AND
MATERIALS
TIP same 163 teeth which hat1 been infused with water-soluble, radiopayuc caontrast medium, radiographed, and subsequent,ly,- subjected to canal preparation ~erc used in this stud>-. The ~ronal opening-s wwc sealed with zinc oxide and c>ugcnol cement i IT.S.l’.) , which was allowed to dry- for on(~ week. Each specimen was immcrsccl in a 70 per cent solution of sodium iothalamate” ant1 subjected to a vacuum at 29 inches of mercury to ensure that the entire canal system had bren permeated with contrast mecliunl. The specimens were then carefully washed with water, tlriccl, and radiographed+ in the proximal, obliquc~. and buecal views with the contrast medium in situ within the canal systems, in i~(‘~()rd~ll~(~ with the procq:tlure previously described.‘” Next, the contrast medium \vas c*lcarctl from each canal system 1)~ forcing water through the tooth under hand prrssurct with the aitl of a large syringe fitted to the tooth at the cervical opening. By reversing the procctdurc with the USC of a small Venturi sucker fitted to the samcl opening, water was r(b\‘crsc flushed through thcb c~lal system when the spctcimcn was immersed in water. Each tooth was radiographed again from the buccal aspect. It was noted after t\\cnty-two spcc%ncns had bocn clcaretl of contrast medium that not all camls werca patent at the apical end. A prcrcyuisite for the acceptanee of all specimt~ns in tlic clarlier esprrimcnt,s”~ I;’ was patency of the: apical openings. Thcl method of test was the creation of a “jet effect” at the apex of
Endodo?Lfic ?)lorphology
Patent Tooth
Root
A. Maxillary I
: 4
5 6
teeth
Single Single Single B
11 6
SinPgle B MBP DB P MB DB
7
SinPgle MB DB P
8
Totals B. Mandibular
studied (total)
80 80 60
50 30 50
64 () (1) 63 87 (>) 63 (1)
;: 6 6
:ii 90 50
:: 30
30 (=) 60 (>j 30 (= 55 (= I 38(=)
!
di
s4 9 ;
2 5.5 50 80
:Ii 45
6 5
35 30
25 20
40 (>) 8 (>I
7
50
25
90
20
72 () -
Sinlgle B L Single B
100 -
45 -
73,)
.i
90
40
54 (>) f:
2 25 70
:: 25
2 30
:P
25 (
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the maxillary and mandibular incisors and canines (93.2 per cent of all canals and 91.7 per cent of all teeth successfully prepared) and the maxillary and mandibular premolars (94.9 per cent of all canals and 91.2 per cent of all teeth successfully prepared). This finding was somewhat surprising since, apart from the widely held belief that molars arc difficult to treat, a considerable number of teeth with canals that exhibited defalcation and dilaceration was included in this st,utIy, more for the sake of checking the efficacy of the infusion technique used in the earlier work than for the purpose of indicating the results accruing from the use of endodontic instruments. The figures pertaining to the incisors and canines are somewhat misleading because of the grouping of the maxillary and mandibular teeth together. A brief perusal of section C of Table III shows a 100 per cent score for the twenty-six maxillary incisors and canines used in the study, whereas section B of Table III shows that the mandibular incisors were the reason for the poor score when all anterior teeth were considered collectively. The high failure rate with mandibular incisors was due to the presence of sufficient specimens containing complex canal systems which not only were difficult to detect in viva but which also could not be satisfactorily negotiated in this series of experiments. The results in this study for successfully prepared mandibular incisors and canines (81.8 per cent) must therefore bc considered when clinical endodontics is being performed on these teeth. It has been reportedz5 that 41.4 per cent of mandibular incisors contain two clinically separate canals, although nearly all of these show apical confluence. In the latter, obturation of one canal at a level which seals the other may well pro\-ide the basis for the success presently enjoyed by clinicians. Suffice it to say, however, that when this is not so, failure is expected to follow because of the prcsvncc of an open canal. In the case of mandibular incisors the creed for JIMoperative clinical and radiographic assessment cannot be too highly stressed. SUMMARY
of root canals during instrumentation, within canals after canal preparation, of endodontic instruments.
the presence ot’ residual traces of alloy and the known and unknown fracturing
REFERENCES
I. Ingle, J. I. : Endodontics, I’l~iladclpllia, lYi4, Lea & Fel)igw, pp. 168, JOO-20 I. 3. Harkcr, 13. c‘. TV., Hession, R. TV., and I,ockctt, H. V.: I’ostcrior Root Canal ‘l’hrrapy. I. Amt. Dent. .J. 11: 168-174, 1966. :I. Barker, B. C. \V.. and Lockett, 1l. (‘. : llwling Following Vital l’ulpwtomy ant1 Root Fill ing, dust. Dn~t. .J. 14: 1+X-1X9, 1969. 1. Sommer, R. I+‘., C)strandrr, E‘. I)., and (Irowley, M. C’. : Chical Entlotlontic~s, cvl. 2, ~‘l~il:~tlcl phia and Lontlo~~, 1961. IV. 13. Saundcw (‘o., pp. 536-537. 5. Ingl?,’ p. 76. 6. Tnglr,’ pp. 54-77. K: 7‘0 Culturc~ 01’ Not to (‘ultuw, 01:.21. SIx(:. i. Bender, 1. Ii., Srltwr, S., xutl ‘I’urkenkopt, 18: 527-540. 1964. Ehtlotiorlti~~ H. Rrldcn, IT. ‘S. : I’ulpopc~riapical I)iw:isc~ : I)isgnosis and ITPilliIlg, a (‘linical Rudy, ORAL SLTRG.37: 271.283, 1974. A Survc~y of I+~ntlodontic~ I)iplomatc~s, Oa.\I 9. Riley, R. R.: Endodontic Recall I’rowtlulc~: SUKG. 37: 118-122, 1974. IO. Goldman, M., Pearson, A. El., :~ud lhwnta, K. : Eutlodontic~ Suw~~ss--\Vho’s Reading tl~, CT., Hmulson, M.L h., au{1 IVeiw, 1;. S.: An lmprow~l Endodontic lnieatiou Twhniaur. ORAI, RTX(;. 36: SXS-X90, 1973.