root - end filling materials play an important role due to their physical , chemical and biological properties .
several materials have been suggested for root - end filling , including amalgam1 , zinc oxide19 , irm9,13 , composite resin15,22 , eba1,14,20 , polycarboxylate cement16 , sealer 2624 , sealapex24 , hydroxyapatite14 , verrm8 and , more recently , mta1,2,6,13,17,23,25,26 .
lysanda is a zinc oxide - eugenol material presented in two pastes ; it is widely used in prosthodontics .
dutra and horta11 ( 1994 ) , custodio and costa7 ( 1994 ) and bernardineli3 ( 1995 ) used this materials for root - end filling with good results and excellent adaptation to the cavity walls .
morais18 ( 2003 ) studied the reaction of rat subcutaneous connective tissue to lysanda paste , mta and portland cement containing iodoform and observed that lysanda paste caused significantly lower inflammatory reaction than mta and portland cement , including formation of a more organized fibrous capsule compared to the other two groups .
bismuth oxide , barium sulfate , zinc oxide and iodoform are radiopacifiers used in endodontics and root - end filling materials4,6,10,21 .
since lysanda paste does not show this characteristic , it is important to determine whether the presence of these substances ( zinc oxide or iodoform ) would alter the properties of this paste and influence the apical marginal sealing of root - end fillings .
the root canals of 50 single - rooted teeth from the tooth bank of the department of restorative dentistry , endodontics and dental materials , dental school of bauru were instrumented by the stepback technique , irrigated with saline , dried with absorbent paper points and filled with gutta - percha , zinc oxide and eugenol by the lateral condensation technique .
the apices were cut into approximately 2 mm at 45 with a # 699 tapered bur in a buccal direction .
the teeth were rendered impermeable by application of fast - setting araldite and nail varnish .
apical cavities were prepared to a depth of 2 mm with # 2 round bur , complemented by irrigation with saline .
the teeth were randomly divided into five groups of 10 teeth each and submitted to root - end filling with the following test materials : group i  lysanda paste with iodoform ; group ii 
lysanda paste with iodoform and zinc oxide ; group iv -lysanda paste with zinc oxide ; and group v  mta . in group
i , 0.62 g of red lysanda paste and 0.46 g of white lysanda paste were placed on a plate , with addition of 0.22 g of iodoform , and were mixed for 30 s. the material was then inserted in the root - end cavity with a blunt - tip probe until complete filling .
procedures for group ii were the same as performed for group i , with addition of 0.22 g of iodoform and 0.11 g of calcium hydroxide . in group iii ,
the procedures were the same as those for group i , with addition of 0.11 g of iodoform and 0.11 g of zinc oxide . in group iv ,
the procedures were the same as for group i , with addition of 0.22 g of zinc oxide . in group
v , mta was prepared by mixing the power with distilled water until the ideal consistency for root - end filling was obtained .
after root - end filling , the teeth were immediately immersed in 2% aqueous methylene blue solution and incubated for 24 hours in an oven at 37c in humid environment , with a small container with water .
then , the teeth were removed from the dye and sectioned buccolingually with a diamond disc , until half of root canal filling and consequently the root - end filling were exposed .
this area was analyzed by reflected light microscopy for determination of leakage at buccolingual interfaces , in millimeters .
data were statistically analyzed by one - way analysis of variance to investigate the possible significant differences between groups .

 table 1 shows the means and standard deviations of apical leakage observed for the experimental groups , namely 0.44 mm for group i ( lysanda+iodoform ) , 0.46 mm for group 11 ( lysanda + iodoform + calcium hydroxide ) , 0.48 mm for group v ( mta ) , 0.68 mm for group iv ( lysanda+zinc oxide ) , and 0.77 mm for group iii ( lysanda + iodoform + zinc oxide ) .
one - way analysis of variance showed no significant differences in apical leakage between the different experimental groups ( table 2 ) .
lysanda paste yielded similar results as the other groups , regardless of the substances added ( table 1 ) .
dutra and horta11 ( 1994 ) analyzing root - end fillings in dog 's teeth , confirmed the high effectiveness of lysanda paste compared to amalgam .
custdio and costa7 ( 1994 ) investigated the marginal leakage of root - end fillings with lysanda , amalgam , ionomer and resin , and observed significantly better results for lysanda .
this is in agreement with the present results , including the observation of excellent adaptation of lysanda paste with its components and of mta .
the addition of other materials to lysanda paste also provided satisfactory results , as shown by the numerical differences that yet were not statistically significant .
the highest leakage rates , without statistical difference , were observed for groups iii and iv , which contained zinc oxide , probably due to lack of affinity between its components .
analysis of table 1 shows that the lowest leakage occurred in group i ( lysanda with iodoform ) , without statistically significant difference compared to mta . according to bramante and berbert5 ( 2000 ) , four aspects are important for the success of root - end filling : the employed material , including its adequate physical , chemical and biological characteristics , is probably the most important factor .
as mentioned earlier , numerous materials have been tested for root - end filling , all of which have advantages and disadvantages , yet certainly without meeting all or most requirements for good sealing . with respect to lysanda paste ,
one of the first studies using this material for root - end filling was conducted by bernardineli3 ( 1995 ) , who demonstrated its high sealing ability and excellent adaptation to the cavity walls , especially when compared to other materials .
these data indicate the possible application of lysanda paste as a new root - end filling material .
however , the addition of radiopaque substances was needed to better test this material . in this respect ,
zinc oxide , calcium hydroxide and iodoform , either alone or in combination , seemed to be the ideal substances for this purpose , due to their good biocompatibility and broad clinical applicability .
the advantages of iodoform as an intracanal medication include the formation of granulation tissue , new bone formation and lesion repair , leading to indication of its use .
zinc oxide and calcium hydroxide also show broad clinical applicability and their biological effects are widely known .
another important aspect is the biocompatibility of lysanda paste ; its good acceptance is mainly related to the clinical indications of the material itself .
morais18 ( 2003 ) , evaluating the reaction of rat subcutaneous connective tissue to mta , portland cement with iodoform and lysanda paste , observed no difference between materials at 7 and 30 days , while at 60 days lysanda paste showed significantly less inflammatory reaction than the other two cements .
an interesting aspect reported by morais18 ( 2003 ) is that the use of iodoform with portland cement , whose combination with other cements is poorly known , yielded satisfactory results when compared to lysanda and even to mta , somehow agreeing with the present results observed for addition of iodoform to lysanda paste .
conversely , in our opinion , the use of lysanda paste is encouraging , even though its indication in dentistry has always been limited . in this context , a very important aspect is its low cost , in contrast to mta , which has a relatively high cost .
the combination of lysanda with other substances was necessary to complement some of its properties , as required for clinical application .
all these observations suggest that mta may still be indicated for root - end filling .
lysanda paste with iodoform yielded the best result and thus can also be considered a good option as root - end filling material , as demonstrated by its positive aspects observed in the present experiment and in previous studies .
studies using lysanda paste are limited , but the definitely promising results encourage further investigations , especially on its biological properties , to confirm its qualities as a root - end filling material and as a possible paste or cement for root canal filling in the future .
lysanda paste with iodoform showed the lowest leakage , without statistically significant difference compared to other groups ; 3 .
 this study aimed to compare the apical sealing of root - end fillings performed with lysanda ( zinc oxide - eugenol paste ) with radiopacifiers ( iodoform or zinc oxide ) and calcium hydroxide . 
 root - end cavities were prepared and filled with different materials , as follows : group i  lysanda paste with iodoform ; group ii  
 lysanda paste with iodoform and calcium hydroxide ; group iii  
 lysanda paste with iodoform and zinc oxide ; group iv  lysanda paste with zinc oxide ; group v  
 mineral trioxide aggregate ( mta ) . after filling , 
 the teeth were immersed in 2% methylene blue for analysis of marginal leakage . 
 it was observed that marginal leakage occurred in all groups . 
 lysanda paste with iodoform showed the lowest leakage , with no statistically significant difference compared to the other groups . 
 all materials can be considered as good options for root - end filling . 