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Aust Endod J 2007; 33: 119–130
Flare-ups in endodontics and their relationship to various
medicaments
Ernest H. Ehrmann, BDSc, DDS, FDSRCS1; Harold H. Messer, MDSc, PhD1; and Robert M. Clark, MSc, PhD2 1 School of Dental Science, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Carlton, Victoria, Australia2 School of Mathematical Sciences, Monash University, Clayton, Victoria, Australia Keywords
Abstract
calcium hydroxide, endodontic therapy,flare-ups, medicaments, pain, VAS scale.
The purpose of this research is to investigate the frequency of endodonticflare-ups using a visual analogue scale. Definitions of flare-ups vary widely as Correspondence
does their reported frequency. A flare-up was defined as an increase of 20 or Dr Ernest H. Ehrmann, 17 Otira Road, Caulfield, more points on the visual analogue scale for a given tooth, within the periods of 4 h and 24 h after the initial treatment appointment. The data from a previous study were used to determine the incidence of flare-ups after using three modalities (Ledermix, calcium hydroxide and no medication) to managepatients presenting for relief of pain of endodontic origin. A statistical analysisshowed that there were no significant differences in flare-up rates at both the4-h and 24-h periods between the three modalities. Further research isrequired using the above definition of a flare-up and standardising treatmentprotocols.
Introduction
or even anti-inflammatory medication during the weekprior to the endodontic consultation. This would result in In the mind of the layperson, there is an association the exclusion of many severe cases from his study.
between undergoing root canal treatment and the occur- Thirty years ago, O’Keefe (35) reported that there was rence of pain. It is obvious that this does occur because a relationship between preoperative and postoperative there is a voluminous literature on the subject of flare- pain levels. This has been confirmed by Genet et al. (13) ups during endodontic treatment (Table 1). What seems who found that 65% of patients reporting with preo- unusual is that there is no agreement among different perative pain had postoperative pain, while only 23% of investigators as to the incidence of such flare-ups. These those with no preoperative pain had postoperative pain.
are said to vary between 1.58% (17) and 90% (16).
Genet’s findings are corroborated by many other investi- Henry et al. (15) stated unequivocally ‘The majority of gators (Claffey et al. (5), Houk et al. (16), Moos et al. (28), patients with symptomatic necrotic teeth had significant Marshall and Walton (24), Nist et al. (32), Nusstein et al. postoperative pain, and required analgesic medication (33)). It can therefore be observed that the single most to manage this pain.’ On the other hand, Trope (44) important determinant of severe postoperative pain is the reported a flare-up rate of only 2.53%. A careful analysis presence of a preoperative painful condition.
of Trope’s data discloses that he included both vital and There is no objective method for measuring pain, as the necrotic pulps in his investigation. It is generally accepted pain experience is very subjective and is dependent on so that the flare-up rate after the extirpation of a vital pulp many factors. In the past, there have been numerous is either non-existent or very low, even if the pulps were methods of pain measurement. These have included tele- painful before instrumentation. In view of this, a flare-up phone interviews on certain days after the endodontic rate of 48.5% after extirpation of a vital pulp as reported procedure and asking patients to describe whether their by Negm (31) seems rather unusual. Another factor in pain has been mild, moderate or severe (4,9,10,11,26) which Trope’s study differs from those of other authors is Several investigators have considered the situation as that it did not include patients who had taken antibiotics painful only if the patient telephones the office with a Journal compilation 2007 Australian Society of Endodontology Journal compilation 2007 Australian Society of Endodontology Journal compilation 2007 Australian Society of Endodontology Journal compilation 2007 Australian Society of Endodontology Journal compilation 2007 Australian Society of Endodontology Journal compilation 2007 Australian Society of Endodontology Table 2 Analysis of variance: preoperative 4 h post-operative
complaint or requests an emergency appointment(17,43,41). Other investigators issued a ‘pain diary’ to thepatient (5,13,21,32,38) and suggested that the patientshould record pain as being mild, moderate or severe.
In order to minimise the various factors and to be able to compare how different procedures can affect the pain Figure 1 The VAS pain scale.
experience it is desirable to use a standard method. Withthis in mind, Rimmer (49) suggested a ‘Flare-up Index’This extends from 0 to 45 and encompasses no fewer than is no absolute measurement for pleasure, there is no nine variables. These include not only different degrees of absolute measurement for pain. Pain still remains a sub- pain but also swelling and trismus. This index has not jective response on the patient’s part to a stimulus. An found acceptance as it is altogether too complicated.
approximation of this scale to more subjective categories In an effort to quantify and measure pain, the visual analogue scale (VAS) has been proposed by Seymour et al.
(50). This is a mathematical progression from 0 to 100, 0 The pain (or visual) analogue scale – VAS
being no pain and 100 being the most severe pain imag- No pain to mild pain, requires no pain killer.
inable. Others have used numbers from 1 to 5 e.g. Abbott Moderate pain requires Aspirin, Paracetamol, et al. (50), Matthews et al. (26), Negm(31); numbers from Ibuprofen, or similar medication for relief.
0 to 9 (Creech et al. 6), or numbers from 1 to 3 Houk (16).
The VAS from 0 to 100 seems the easiest to use because it does away with decimal points. The introduction of the Visual Analogue Scale has introduced some consistency into the results. Nevertheless, it is realized that the VAS is Extreme pain, pain not relieved by any mea- only suitable for use in an academic or research environ- ment and not in routine clinical practice.
Figure 1 is a horizontal representation of the pain scale.
Table 1 summarises the studies into flare-ups. It will be seen that there are many variables that have not beenstandardised and that there is a great variation in the Materials and methods
actual flare-up rates. Above all there is no satisfactory definition of a flare-up. Some investigators (Mata et al.
(25), Peters (36), Torabinejad (41), Walton and Fouad The outline of this clinical trial was approved by the (47), Mor et al. (29), Oguntebi et al. (34)) suggest that a Ethics in Clinical Research Committee of the Royal flare-up occurs when the patient requests a nonsched- Dental Hospital of Melbourne. The trial was explained to uled emergency appointment. Any definition of flare-up patients who signed a form agreeing to treatment.
must be arbitrary to some extent. If a flare-up is defined This investigation was confined to teeth that were non- as a relatively small increase in pain, there will be many vital and painful. All patients presenting for treatment such cases. Conversely, if a flare-up is defined as a rela- were included in the trial provided the tooth was func- tively large increase in pain, there will necessarily be very tional and the patient was willing to undergo endodontic few such cases. As a practical solution to this problem, for treatment. Teeth with a fluctuant facial swelling were not the purposes of this study a flare-up was defined as a rise accepted because it was felt that relief is often obtained of 20 or more points on the VAS. This corresponds to simply by incision and drainage. Full details of the 221 approximately one residual standard deviation as given in patients have been reported previously (Ehrmann et al. the Analysis of Variance table (see Table 2). This defini- tion was then used in the subsequent statistical analyses At the initial visit the following conditions were applied to data that is available in Ehrmann et al. (51).
recorded: presence or absence of mild swelling, sensitivity The VAS at least attempts to be quantitative. Just as there to percussion, presence of a periapical lesion, previous Journal compilation 2007 Australian Society of Endodontology treatment, presence or absence of a coronal restoration/ with the patient, the pain score for the previous night was seal, administration of a preoperative analgesic or antibi- recorded. The patient was then requested to record the otic. Before commencing treatment, the aims of the study pain score 4 h after the completion of treatment and then were explained to the patient and their consent was obtained. When the patient so requested, a local anaes- No antibiotics were prescribed and where patients had thetic was administered. All caries and all suspicious been taking antibiotics this was recorded. Patients were restorations were removed and were replaced with then requested to stop taking the antibiotics. They were intermediate restorative material (IRM). Most posterior also requested to stop taking analgesics, with the proviso teeth were banded with stainless steel bands particularly that if pain were to persist or recur analgesics could again where caries had extended subgingivally. The tooth was be taken. Prior to the trial, nine vital painful teeth (irre- isolated under rubber dam, access was obtained and the versible pulpitis) were treated according to the above canals were measured and instrumented using the step criteria. It was found that all pain either disappeared back technique. Throughout the treatment teeth were within 24–48 h regardless of the dressing used or if any irrigated with Milton’s solution (1% sodium hypochlo- pain remained it was of negligible proportions. As a result rite) alternating with 15% EDTAC. At the conclusion of it was decided to exclude vital painful teeth from the trial.
treatment the canals were dried and were medicated with Originally there were 223 teeth belonging to 221 one of the following medicaments randomly selected patients in the trial. However the data from only 195 teeth were analysed. The reasons for the exclusion of 28 teeth 1. Group 1 – Ledermix paste (Riemser Arzneimittel Wolf-
were given in the previous paper (Ehrmann et al. 51).
sratshausen, Germany).
2. Group 2 – Calcium hydroxide paste.
3. Group 3 – No dressing; the canals were left empty.
Changes in pain levels 4 h and 24 h after treatment Ledermix and calcium hydroxide were inserted into the dried root canal by means of a file that was at least Figures 2 and 3 show histograms for each treatment two sizes smaller than the file last used to approximately modality, of the changes in pain level from preoperative to two millimetres of the apex. Cavities were sealed with 4 h and 24 h after treatment. Change was defined so that either IRM or Cavit. At the conclusion of each appoint- negative values correspond to an improvement (reduc- ment, each patient was handed an evaluation sheet and tion) in pain level and positive values correspond to an the VAS was explained to the patient. In consultation increase in pain level. At both postoperative time periods Figure 2 Change in pain level from preoperative to 4-h postoperative. Vertical dashed line corresponds to the definition of ‘flare-up’.
Journal compilation 2007 Australian Society of Endodontology Figure 3 Change in pain level from preoperative to 24-h postoperative. Vertical dashed line corresponds to the definition of ‘flare-up’.
and for all treatment modalities, a wide range in the Table 3 Incidence of flare-up, 4 h post-operative
extent of change was evident (from a reduction of -90 to an increase of +60). The majority of patients recordeda reduction in pain level in all treatment groups. A one- way Analysis of Variance (Table 2) suggested that there were possible differences in the mean change in pain level from preoperative to 4 h (P = 0.03). A similar analysis indicated no significant differences from preop- The corresponding c2-statistic was 2.841, with a P-value of 0.252.
erative to 24 h (P = 0.104). These significance levelsmust be treated with caution, since the data are clearlynot normally distributed. Accordingly, the nonparamet- Incidence of flare-ups
ric Kruskal Wallis test was used to compare the medianchange in pain level in response to the three treatments.
As noted above a flare-up was defined as an increase in A marginally significant (P = 0.04) difference in median pain level of 20 or more on the VAS, since any smaller levels was noted 4 h postoperatively, with the Ledermix increase could be explained by random variability (based group significantly lower by approximately 10 units on on the standard deviations of the residuals in both Analy- the VAS than either the calcium hydroxide group ses of Variance). The incidence of flare-ups at 4 h and 24 h is summarised in Tables 3 and 4. The proposed defi- (Mann–Whitney post hoc tests). No differences were nition of flare-up is indicated by the dashed vertical line in Figures 2 and 3. The overall incidence was 12.3% at The sensitivity of this statistical analysis is measured by 4 h (24/195) and 6.7% at 24 h (13/195). No significant the power, which in this case is the probability of cor- differences among treatment groups were found at either rectly detecting a difference in the flare-up rates between time period (Chi square test, P = 0.252 and 0.161 at 4 h the three treatments. This probability depends on the actual (true) flare-up rates. With the large samples avail- Flare-up rates and confidence intervals (C.I.) expressed able here, the power is relatively high. For example, if the in percentages are to be found in Table 5. All confidence difference in flare-up rates is 15% (5% to 20%, close to intervals overlap one another, confirming that there are the estimated rates) then the power is approximately no statistically significant differences in the incidence of flare-up. It will be noted that at 4 h the flare-up rate for Journal compilation 2007 Australian Society of Endodontology Table 4 Incidence of flare-up, 24 h post-operative
this procedure is out-weighed by the problem of furthercontamination of the canal space.
Another unusual finding was that by Peters (36) who reported that postoperative pain frequency for patients treated in one appointment was higher (16%) than patients treated in two appointments (9.6%). Most other studies (Albashaireh and Alnehrish (3), Eleazer and The corresponding c2-statistic was 3.840, with a P-value of 0.161.
Eleazer (8), Fox et al. (56)) found that one-visit treat-ments resulted in less pain than those taking two visits.
Again, use of standardised scoring systems would allow a Table 5 Flare-up rates and 95% confidence intervals (C.I.) expressed in
While it is not the focus of this study, the management of flare-ups or their prevention also merits brief mention.
In order to reduce pain and swelling after an endodontic intervention many practitioners prescribe antibiotics. This is somewhat controversial. One study by Mata et al. (25) found that the administration of penicillin V at the first visit and continued for one week thereafter resulted inless pain than a placebo. A case was designated as aflare-up when the patient had pain and/or swelling that Ledermix was 6.9%, which was less than that for calcium necessitated an unscheduled emergency visit. In another hydroxide or for no dressing, but not significantly differ- very similar study, Abbott et al. (52) compared the efficacy ent. This is in accordance with the work of Abbott et al. of penicillin V with that of erythromycin and found no (52) who found that the rate of release of triamcinolone difference. They both were said to lower the incidence of into the tissues from the tooth was highest during the flare-ups. In a third study, Morse et al. (30) compared first 3–8 h and declined exponentially thereafter and cefadroxil with erythromycin and a low (2%) flare up Ehrmann et al. (51) who found that the efficacy of Led- rate was claimed. Controls were only used in the first ermix was most marked at 4 h postoperatively.
paper cited. They were not used in the later papers.
The opposite view was held by Walton and Fouad Discussion
(47) who found no statistical difference in pain experi-ence when antibiotics had been used. However their It has been observed that when the pain is either nonex- definition of a flare-up differed from those reported by istent or mild an increase of 20 points in the VAS scale of Morse and his group. Patients who called their practi- pain would still only be in the category of no or mild pain.
tioner with a problem were asked to report to the clinic Out of 24 cases of flare-ups at 4 h, there were three cases immediately. A decision was then made whether active in this category. Their initial pain scores were 0 or 5 and treatment was necessary. Simply talking to the patient their pain reading at 4 h was 25. A score of 25 is the and prescribing or dispensing medication did not con- highest entry for a patient with no or mild pain. However stitute a flare-up. A flare-up was recorded only when it is also the lowest entry for a case where the pain is treatment was carried out. As their definition of a flare- moderate and an analgesic is required. Out of 13 flare-up up is different from that of Morse, their results are not cases at 24 h there was one case with an initial score of 5 strictly comparable. In another study Walton and Chi- and a final score of 25. The same remarks as above would appinelli (48) were able to confirm their earlier findings that systemic penicillin does not alter the pain experi- For many years, it was common practice to provide ence. What is of great interest is that they used the emergency relief in the case of an acute abscess by leaving occurrence of an unscheduled appointment as a mea- the canal open (Sommer et al. 53, Siskin 54). As late as surement of a flare-up and the visual analogue scale to 1988 this was still being advocated by some authors measure pain. The two are clearly related and it would (Grossman et al. 55). None of the studies cited in this be simpler if the VAS were to have been used to record paper have advocated this course of action. Leaving a canal open introduces more organisms into an infected With regard to the VAS it must also be realised that tooth thus negating all principles of modern endodontics when no preoperative pain is present, an increase of 20 which strive to eliminate bacteria from the root canal points in the VAS is not very significant as such pain is still system. Any benefit in terms of relief of pain achieved by only mild and does not require an analgesic.
Journal compilation 2007 Australian Society of Endodontology 12. Fouad AF, Rivera EM, Walton RE. Penicillin as a Conclusion
supplement in resolving the localized acute apical A reasonable definition of a flare-up would be an increase abscess. Oral Surg Oral Med Oral Pathol Oral Radiol of 20 or more points on the Visual Analogue Scale. A statistical analysis of pain data from 195 cases showed 13. Genet JM, Hart AAM, Wesselink PR, Thoden Van Velzen that the use or type of intracanal medicament did not SK. Preoperative and operative factors associated with alter the frequency of flare-ups. Hence there was no pain after the first endodontic visit. Int Endod J 1987; difference in the flare-up rates at 4 h or 24 h between 14. Glassman G, Krasner P, Morse DR, Rankow H, Lang J, Ledermix, calcium hydroxide or no dressing. Further Furst ML. A prospective randomized double-blind trial research is required using the above definition of a flare- on efficacy of dexamethasone for endodontic interap- up and standardising treatment protocols.
pointment pain in teeth with asymptomatic inflamedpulps. Oral Surg Oral Med Oral Pathol 1989; 67: Acknowledgments
The assistance of Dr Kurien Mamootil in providing a list 15. Henry M, Reader A, Beck M. Effect of penicillin on post- operative endodontic pain and swelling in symptomaticnecrotic teeth. J Endod 2001; 27: 117–23.
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