The most significant finding of this study was reduction in spontaneous pain and percussion sensitivity by use of corticosteroid containing material as an interappointment medicament compared to control group. Endodontic literature contains few studies regarding the efficacy of Ledermix (Haupt Pharma GmbH, Wolfratshausen, Germany) a corticosteroid/antibiotic mixture in comparison with other intracanal medicaments, but there is a few studies about Odontopaste. Ehrmann et al. found that the flare-up (pain and/or swelling) scores mean of Ledermix was significantly lower than the flare-up scores mean of control group (
14). Our study showed similar pain and percussion sensitivity reduction for Odontopaste® in acute apical periodontitis, 24 hours after the first appointment. One of the active ingredients of Odontopaste® is triamcinolone. Abbott et al. in their in-vitro study evaluated the rapidity and prompt action of triamcinolone in Ledermix. They concluded that the rate of release of triamcinolone is in maximum level during the first 3-8 hours, but it reduced after 8 hours (
15). There is controversy about antimicrobial efficacy of intracanal medicaments, some authors believe that these are not efficient enough against microbial biofilm, and have mentioned that antimicrobial effect is necessary (
16). Trope did not found any difference between Ledermix, Calcium Hydroxide and Formocresol in flare-up rate reduction. He reported very low rate of flare-up (only 2.53%: 12 in 474 cases) which may be due to his meticulous adherence to exclusion criteria (
17). Genet et al. observed a flare-up rate of 27% in all treated cases. These investigators also found a direct correlation between preoperative pain and the incidence of postoperative pain (
18). Seltzer criticized the use of corticosteroids in endodontic therapy by stating that the disadvantage of using corticosteroids derives from its effects on inflammatory cells. He stated that inflammatory cells hamper the process of phagocytosis and protein syntheses, which may result in delayed healing (
19). But Abbott disproved these findings and said that even if corticosteroids cause some adverse effects, they are of minor degree and insignificant (
20). Ledermix Paste has been recommended for endodontic use due to its anti-inflammatory effect (
21). Odontopaste has recently been released onto the dental market, similarly due to its anti-inflammatory effect and no adverse effect on tooth color. The main difference between Odontopaste and Ledermix Paste is in its antibiotic ingredient: clindamycin hydrochloride in Odontopaste replaces demeclocycline hydrochloride in Ledermix Paste. Clindamycin hydrochloride has an equivalent spectrum of antibacterial activity but exhibits minimal staining of teeth (
22). There are different recommendations for mixing Ledermix or Odontopaste with calcium hydroxide. Calcium hydroxide can be mixed with the Ledermix paste (as an approximate 50:50 mixture) or it can be used as a separate subsequent dressing in canal (
15,
23). Although Odontopaste itself has about 0.5% calcium hydroxide in its combination, mixing of additional calcium hydroxide in a 50:50 combination with Odontopaste is not recommended. Athanassiadis et al. observed rapid loss of steroid when Odontopaste or Ledermix was mixed with calcium hydroxide powder, although the overall destruction of steroid in Odontopaste was less (
11).
It seems that there is no real advantage for mixing calcium hydroxide with Ledermix or Odontopaste. There is no significant antibacterial enhancement in these calcium hydroxide combinations when compared to calcium hydroxide alone (
24). So in this study calcium hydroxide was not used with Odontopaste or the other medicament. There are controversies about the effect of age on postoperative pain incidence. Balban found that with advancing age, the percentage of cases with acute exacerbation of interappointment pain decreased. The reason he gave was that, in old age the pulp canal size decreases significantly. Thus there would be a decreased volume of debris, reduced flow of blood to the alveolus, and thus reduced inflammatory response to infection (
25). Another study, a prospective randomized trial conducted by Morse et al. concluded that no direct or indirect association could be established between the incidence of interappointment pain and age of patients (
26). On the contrary, there are some studies that reject the idea given above. Some researchers concluded that patients above 50 years are more prone to develop interappointment flare-ups. The reason given was that, the cementum deposition increases with age; therefore, coronal transportation of radiographic apex may occur. This would lead to increased possibility of developing errors in determining the working length and apical extrusion of the debris, thus patients in old age have more chance of developing interappointment flare-up than younger patients (
25,
27). Due to these controversies, one of the inclusion criteria in this study was age limitation.
Corticosteroids containing intracanal medicaments like Odontopaste® reduce postoperative spontaneous pain rate and percussion sensitivity significantly, 24 hours after the first appointment, but our study did not show any significant effect 7 days after the first appointment.