Endodontic success-Who’s reading the radiograph? Melvin Goldman, D.D.S.,” Arthur H. Pearson, D.N.D.,‘* Nicholas Dnrzenta, D.D.S., D.X.D.,‘“” Boston, Mass. TUFTS USIVERSITY SCHOOL OE’ DENTAL and MEDICINE Success and failure in 253 cases selected at random were the films and having six examiners read them, independently ing one another. They agreed on fewer than half of the was only one of determining whether or not an area of on one film, the agreement was still less than half. Upper percentage of disagreement, but all the other teeth gave agreement also. T determined by mounting and without consultcases. When the question rarefaction was present molars gave the greatest large percentages of dis- he endodontic literature is replete with success and failure studies. Those of Strindberg,l Bender and associates,* Storms,3 and Heling and Tomshe are representative examples of some of the more recent ones. All of the authors exa.mined the success and failure percentages from various aspects. Strindberg studied the overfilling-underfilling asp&, whereas Bender and Seltzer studied t’he positive or negative culture aspect. Others compared silver cones and guttapercha fillings. Each group was meticulous in its approach and carefully reported its findings. However, most of the results were based on the interpretation of radiographs, and upon this rather questionable foundation the whole structure of each study was based. Anyone who has rendered endodontic therapy knows that on many occasions the radiograph is misleading. Is there an area of radiolucency? Where is the apex of the root? How large is the area? These and many other problems trouble all of us each day, Bender and Seltzer5 have shown in their study of radiographic diagnosis that, unless an area of bone destruction encroaches on the cortical plate, it is usually not evident on a radiograph. *Associate **Professor ***Associate 432 Clinical Professor in Endodontics. and Chairman of Department of Endodontics. Professor in Radiology. Volume 33 Number 3 Radiographic diagnosis in endodontics 433 Table I Observer Success FCLilzlV~ 203 6 12 9 41 28 48 1 189 4 5 6 199 170 202 162 Questionable The following study was designed to investigate the reliability graphic diagnosis. 44 52 45 42 23 43 of radio- METHODS AND MATERIALS Two hundred fifty-three cases from the files of an active endodontic practice were selected at random. The criteria used were: (1) All the teeth were comfortable, asymptomatic, and without fistulas. i2) Both a radiograph of the completed root canal filling and a checkup radiograph taken at least 6 months after completion were available. The cases were selected completely at random; the person selecting the caseswas not told the purpose for which they were to be used. The radiographs were mounted and numbered, and the status of the pulp at the beginning of treatment was recorded. The radiographs were then read and recorded completely independently of one another by six different examiners. The following criteria for successand failure were established : I. Vital pulp A. Success-No area at beginning, no area on checkup B. Failure-No area at beginning, area on checkup II. Pulpless-without area A. Success-No area at beginning, no area on checkup B. Failure-No area at beginning, area at checkup III. Pulpless-with area A. Success-Area at beginning, area healed or definitely smaller at checkup B. Failure-Area at beginning, area larger at checkup IV. Questionable A. Cannot decide whether area is present B. Cannot decide whether area is larger, smaller, or samesize C. Bad film The examiners were two endodontists, one with 25 years of experience, the other with 20; an associate professor of radiology; and three second-year graduate endodontic students .# The results were analyzed and catalogued. RESULTS There were 253 cases: 159 teeth were pulpless, and 94 were vital. Table I shows the total number of successes,failures, and questionables of *Dr. Alan L. Levick, Dr. Paul 5. Scols, and Dr. Hugh Tresnor. Table II each examiner. The number of failures ranged from six to forty-eight. The number of questionables ranged from twenty-three to fifty-two. The examiners were asked to judge only the completed films of the 159 pulpless cases (not the checkup films) and to determine whether there was an area of rarefaction. The results varied from twenty-eight teeth without an area to seventy-six without an area (Table II). If we continue the breakddwn further in order to ascertain whether there were certain cases which were confusing to all, the analysis showed that, in a consideration of the success-failure-questionable category only, all six examiners agreed on 119 of 253 cases, or 47 per cent of the time. If we look at the casesin which five of the six examiners agreed, there were fifty-two additional casesfor a total of 171 of 253, or 67 per cent. If we consider the pulpless cases and those in which a single judgment of one film was involved, the six examiners agreed sixty-seven out of 159 times, for a total of 42.1 per cent. Again if we consider the cases in which five of the six agreed, there were forty-seven additional cases for a total of 114, or 71 per cent. If we combine Tables I and II, all six examiners agreed (in the successfailure-questionable category plus the pulpless with or without area) in seventyseven of 253 cases, or 30.4 per cent,. Again, five out of six agreed in an additional fifty-seven casesor 134 of 253, or 53 per cent of the time. Since it might be thought that six examiners were too many, the results were analyzed for two groups of three examiners. Examiners No. 1, 2, and 3 in the success-failure-questionable category agreed in 165 of 253 cases, or 65 per cent of the time. If we consider only the pulpless with or without area, they agreed in ninety-eight of 159 cases,or 61 per cent of the time. The second group consisting of Examiners No. 4, 5, and 6 agreed in the success-failure-questionable category in 143 of 253 cases, or 56 per cent of the time. In the pulpless with or without area, they agreed in 104 of 159 cases, or 65 per cent of the time. Even further, if we consider only two of the examiners, No. 4 and No. 6 (selected because they were the most critical of all the examiners), they agreed in the success-failure-questionable category in 187 of 253 cases, or 73 per cent of the time. In the pulpless category, they agreed in 125 of the 159 cases,or 78 per cent of the time. Of the total of 253 cases, there were 109 which everyone agreed were Volume Number 33 3 Radiographic diagnosis in endodontics 435 Table III Upper Agreed 15 Lower Agreed 2 anterior Disagreed 11 anterior Disagreed 2 VITAL Upper Agreed 6 Lower Agreed 7 CASES premolar Disagreed 8 premolar Disagreed 5 Upper Agreed 3 Lower Agreed 11 molar Disagreed 14 molar Disagreed 11 Upper Agreed 28 Lower Agreed 6 anterior Disagreed 34 anterior Disagreed 9 PULPLESS CASES Upper premolar Agreed Disagreed 14 17 Lower premolar Agreed Disagreed 8 4 Upper Agreed 5 Lower dgreed 14 molar Disagreed 10 molar Disagreed 9 successful, seven cases which everyone agreed were questionable, and three cases which everyone agreed were failures. Table III is a breakdown of the various teeth involved. The upper molars were the most difficult for everyone to reach agreement upon. But even in upper anterior teeth in the pulpless categories, more cases were disagreed upon than were agreed upon. DISCUSSION It is clear that the radiograph is a very questionable means of determining success and failure. This is not surprising, for we interpret radiographswe do not read them. To read is to see a group of letters that make up a word. Everyone sees the same letters and reads them. Radiographs have to be interpreted, and so many factors and variables enter into what we see that the whole procedure becomes exceedingly confusing. For instance, the mental state of the examiner is involved-Was he tired? Was he upset by a quarrel? Did he view the films in the morning or at night? What instructions were given to him? Factors such as these may enter into the interpretation that he renders. The results speak for themselves. In the success-failure-questionable category, a judgment and comparison had to be made. That is, both radiographs had to be interpreted and a judgment made for each, and then one had to be compared to another. This resulted in 47 per cent agreement. Even when we required only five of six examiners to agree, we still had only 67 per cent agreement. It might be said that this is possible because of the probability of difference in the density of the film, the angle of the primary beam, possible differences in developing and fixing, etc. However, every examiner was looking at the same films, so that angulation, density, etc., would tend to cancel out. But, if we assume that there is merit to the above-mentioned objections, consider Table II. Here no comparison was involved. Only one judgment on one film had to be made-whether an area was or was not present. And the puzzling thing 436 Goldman, Oral March, Pea,rson, u?ld Darxenta Surg. 1972 is that there was only 42.1 per cent agreement by all six examiners. This uas slightly less than tht sncc.ess-faill~re-qnestionahlc category in whicl~ ;I cornparison was involved. Reducing the number of examiners did raise the percentage of agrremcnt somewhat, but not anywhere near reliable levels. Only two thirds of the time did three examiners agree. Going even further and reducing the number of examiners to two and even select,ing the two most critical ones (No. 4 and No. 6) raised the agreement level of the success-failure-questionable category to 73 per cent. They disagreed on sixty-six cases! In the pulpless category they agreed only 78 per cent of the time and disagreed on thirty-eight cases! It is interesting that the examiner who found only six failures was the one who had treated a large number of the patients. The two examiners who found nine and twelve failures also had treated many of the patients. The other three who found twenty-eight, forty-one, and forty-eight failures had not treated any of the patients. The examiner who found forty-eight failures was the radiologist, who, by training, considered factors which the endodontists did not. Table III indicates the location of teeth and shows that upper molars were the most difficult ones to agree upon. But even upper anterior and lower anterior teeth, which should be the easiest of all teeth to obtain good, clear films of showed a large percentage of disagreement. What this means in terms of success and failure studies is unclear. Should several persons evaluate all films? Should they confer and reach a consensus? If one of the group is a dominant personality by virtue of training or position, will this influence the others? These and many other questions remain unanswered, but all future studies must take these factors into consideration. Further analyses of these films are being made at present and will hc reported at a later date. SUMMARY Success and failure of 253 cases selected at random were determined by mounting the films and having six examiners read them. All examiners read the films independently and without consulting one another. They agreed on less than half of the cases. When the question was only one of determining whether an area of rarefaction was or was not present on one film, the agreement was still less than half. Upper molars gave the greatest percentage of disagreement, but all the other teeth gave large percentages of disagreement also. the The authors wish to acknowledge Wistar Polytechnic Institute the invaluable Computer Center assistance of Mr. Richard in compiling the data J. Schwartz of for this study. REFERENCES 1. Strindberg, L. 2.: The Dependence of the Acta Odontol. Stand. 14 Supp. 21, 1957. 2. Bender I. B., Seltzer, S., and Turkenkopf, 18: 52s540, 1964. Results S.: of Pulp To Culture Therapy or Not on Certain to Culture, Factors, ORAL SURG. Volume Number Ra,diographic 33 3 diagnosis in endodontics That Influence the Success of Endodontic 3. Storms, J. L.: Factors Dent. Assoc. 35: 83, 1969. Evaluation of Success of Endodontically 4. Heling, B. and Tomshe, A.: ORAL SURG. 30: 533-536, 1970. 5. Bender, I. B. and Seltzer, S.: Roentgenologic and Direct Observations Lesions in Bone, J. Am. Dent. Assoc. 62: 152-160, 1961. Reprint requests to: Dr. Melvin Goldman Department of Endodontics Tufts University School of Dental 136 Harrison Ave. Boston, Mass. 02111 Medicine Treatment, Treated of 437 J. can. Teeth, Experimental
