the main aim of an endodontic obturation is to obtain a fluid tight hermetic seal of the entire root canal system ( rcs ) . the presence of great anatomic complexity of the rcs , has advocated the evolution of different materials and techniques to achieve the desired fluid tight hermetic seal . gutta - percha , in combination with sealer , is the most widely used solid material for endodontic root canal obturation . cold lateral condensation as an obturation technique is widely practiced throughout because of its advantages of controlled placement of gutta - percha in the root canal and low cost . the final filling is composed of a large number of gutta - percha cones tightly compressed together and joined by frictional grip and root canal sealer , rather than a homogeneous mass of gutta - percha . there is usually presence of voids because of spaces between individual gutta - percha cones and the root canal walls . this can be seen with poor root canal preparations , curved canals , inadequate lateral pressure during condensation or mismatch between gutta - percha cones and the prepared root canals . such obturations would lack homogeneity and have to depend on sealer to fill the voids and thus would have a poor prognosis . because gutta - percha obturation techniques generally require some type of condensation ( lateral , vertical ) their final radiographic appearance may or may not be as expected due to variations in appearance such as sealer voids , spreader tracks , condenser voids and material welds ( in the case of heated techniques ) . while various studies have attempted to relate these aberrancies with case unacceptability and failure , little correlation exist at present ; except for the standard that a dense , well - adapted root - filling is clinically and radio graphically acceptable . since the introduction of thermoplastic obturation techniques in 1967 by schilder , new devices and systems using thermoplasticized gutta - percha as root canal filling material have been developed . the sectional backfill technique with thermoplastic gutta - percha is one of these options , consisting of an apparatus for heating and injecting thermoplasticized gutta - percha into the root canal . this technique has shown better adaptation to the root canal walls in comparison to lateral condensation , and also result in successful filling of simulated lateral canals . the most recent advancement in endodontic obturating materials uses a hydrophilic polymer in the root canal , the smartseal system ( prosmart - drfp ltd . , stamford , uk ) . the system consists of obturation points ( pro - points ) containing a polyamide core with an outer bonded hydrophilic polymer coating and an accompanying sealer which is further provided with polymer powder to be incorporated during the manipulation of the sealer . the endodontic points are designed to expand laterally without expanding axially by absorbing residual water from the instrumented root canal space and the naturally present moisture in the dentinal tubules . the inner core of pro - points is a mix of two proprietary nylon polymers : trogamid t and trogamid cx . the polymer coating is a cross - linked copolymer of acrylonitrile and vinylpyrrolidone which has been polymerised and cross - linked using allyl methacrylate and a thermal initiator . the lateral expansion of pro - points is claimed to occur nonuniformly with the expand - ability depending on the extent to which the hydrophilic polymer is prestressed ( i.e. , contact with a canal wall will reduce the rate or extent of polymer expansion ) . different techniques and root canal materials have been used for evaluating obturation in a simulated lateral canal . both natural and artificial teeth have been used for in order to simulate the lateral canals . natural teeth have been more commonly used as evaluation can be done by radiographic methods , decalcification , clearing methods or a combination of both . to the best of our knowledge , there is no reported study comparing novel smartseal system and gutta - percha system using simulated lateral canals using decalcification methods and cone beam computed tomography ( cbct ) image analysis . the homogeneity of the materials has been evaluated using cbct with axial sections obtained at coronal , middle and apical levels . because we were evaluating a new material , a three - dimensional ( 3d ) evaluation by cbct was advised to further substantiate the results . a total of 60 freshly extracted human single rooted teeth with fully formed apices were selected for this study . teeth were de - coronated and roots were standardized to a working length ( wl ) of 15 mm . root canal preparation was subjected to crown down technique with rotary protaper files until file size f2 with full sequence . after each file 1 ml of 3% sodium hypochlorite was used as an irrigating solution delivered with 27-gauge side venting needles inserted 3 mm from the apex . ethylenediaminetetraacetic acid ( edta ) gel ( rc help ) was used as a lubricant . this was followed by a rinse of 3 ml of 17% edta for 1 min . after completion of root canal preparation ten specimens from each group were subjected to a tooth decalcification and clearing protocol previously described by venturi et al . specimens were decalcified in a solution of 5% hydrochloric acid ( hexis cientfica s / a , jundia , sp , brazil ) which was changed every 24 h for 5 days . teeth were de - mineralized until they achieved a rubber - like consistency . later , # 8 and # 10 k - files were inserted through the buccal and lingual root surfaces at 2 , 4 , and 6 mm from the wl until they reached the main root canal , creating the simulated lateral canals . the patency and standardization of lateral canals were tested with # 8 or # 10 k - file . in order to eliminate the acid , teeth were washed in running tap water for 4 h and dehydrated using increasingly concentrated serial dilutions of alcohol , which reverted the specimens back to its hard consistency . finally , specimens were immersed in ethyl salicylate ( vetec qumica fina ltda , rio de janeiro , rj , brazil ) in order to render the tissues transparent . remaining ten specimens from each group were mounted on modeling wax for cbct analysis . group a : smartseal systemgroup b : sectional backfill techniquegroup c : cold lateral condensation technique 
  group a : smartseal system group b : sectional backfill technique group c : cold lateral condensation technique group a : teeth were obturated with 6 taper master polyamide polymer cone using single - cone technique with no accessory cones being used . the sealer used in this group was smartpaste sealer ( prosmart - drfp ltd.stamford , uk ) an epoxy amine resin - based sealer with active polymer powder . group b : teeth were obturated using sectional backfill technique with 6 taper gutta - percha cone seared off 4 mm from the apex and the remaining canal backfilled with warmed gutta - percha . group c : teeth were obturated using cold lateral compaction technique . a f2 0.06 taper gp cone ( diadent , vancover , bc , canada ) was placed to wl . a fine size finger spreader was advanced to within 1 mm of the wl or to resistance , rotated and removed . a size # 25 0.02 taper accessory gp cone ( tulsa dental ) was placed into the prepared space . this was repeated until no more than 2 mm of the spreader could be advanced into the canal . excess gp was removed with a # 15 scalpel blade at the coronal root surface . sealer used in groups b and c was ah plus ( dentsply maillefer ) ; an epoxy amine resin - based sealer . after obturation , all the specimens were stored at a temperature 37c for duration of 24 h to allow complete setting of the sealer . proximal radiographs of each specimen ( kodak rvg 6100 ; kodak dental systems , atlanta , ga , usa ) were taken using the spectro 70 electronic x - ray unit after standardizing the positioning of the roots and the focus - film distance . then , specimens were soaked once again in methyl salicylate , and standardized digital photographs were taken ( nikon d80 ; nikon , tokyo , japan ) . the radiographic and photographic images showing the root canal fillings in each specimen were imported into the image tool software ( uthscsa image tool for windows version 3.0 , san antonio , tx , usa ) . the amount of filling material observed in each lateral canal at the level of 2 , 4 and 6 mm was calculated by single calibrated examiner . the data were expressed as linear extension ( length in mm of the lateral canal that was filled in relation to its entire length ) and of the area filled ( area in millimeter square occupied by the filling material inside the lateral canal in relation to its entire area ) . the cbct scans were done using promax 3d mid ( planmeca oy helsinki , finland ) . the samples were mounted on wax block for stabilizing them and were exposed to the cbct scans with 90 kv and 8 ma with field of view of 4.5 cm  4.5 cm and an isotropic resolution of 2 mm resulting in 400 - 450 slices per tooth with exposure time of 12.28 s. a total of 60 freshly extracted human single rooted teeth with fully formed apices were selected for this study . teeth were de - coronated and roots were standardized to a working length ( wl ) of 15 mm . root canal preparation was subjected to crown down technique with rotary protaper files until file size f2 with full sequence . after each file 1 ml of 3% sodium hypochlorite was used as an irrigating solution delivered with 27-gauge side venting needles inserted 3 mm from the apex . ethylenediaminetetraacetic acid ( edta ) gel ( rc help ) was used as a lubricant . this was followed by a rinse of 3 ml of 17% edta for 1 min . after completion of root canal preparation ten specimens from each group were subjected to a tooth decalcification and clearing protocol previously described by venturi et al . specimens were decalcified in a solution of 5% hydrochloric acid ( hexis cientfica s / a , jundia , sp , brazil ) which was changed every 24 h for 5 days . teeth were de - mineralized until they achieved a rubber - like consistency . later , # 8 and # 10 k - files were inserted through the buccal and lingual root surfaces at 2 , 4 , and 6 mm from the wl until they reached the main root canal , creating the simulated lateral canals . the patency and standardization of lateral canals were tested with # 8 or # 10 k - file . in order to eliminate the acid , teeth were washed in running tap water for 4 h and dehydrated using increasingly concentrated serial dilutions of alcohol , which reverted the specimens back to its hard consistency . finally , specimens were immersed in ethyl salicylate ( vetec qumica fina ltda , rio de janeiro , rj , brazil ) in order to render the tissues transparent . group a : smartseal systemgroup b : sectional backfill techniquegroup c : cold lateral condensation technique 
  group a : smartseal system group b : sectional backfill technique group c : cold lateral condensation technique group a : teeth were obturated with 6 taper master polyamide polymer cone using single - cone technique with no accessory cones being used . the sealer used in this group was smartpaste sealer ( prosmart - drfp ltd.stamford , uk ) an epoxy amine resin - based sealer with active polymer powder . group b : teeth were obturated using sectional backfill technique with 6 taper gutta - percha cone seared off 4 mm from the apex and the remaining canal backfilled with warmed gutta - percha . group c : teeth were obturated using cold lateral compaction technique . a f2 0.06 taper gp cone ( diadent , vancover , bc , canada ) was placed to wl . a fine size finger spreader was advanced to within 1 mm of the wl or to resistance , rotated and removed . a size # 25 0.02 taper accessory gp cone ( tulsa dental ) was placed into the prepared space . this was repeated until no more than 2 mm of the spreader could be advanced into the canal . excess gp was removed with a # 15 scalpel blade at the coronal root surface . sealer used in groups b and c was ah plus ( dentsply maillefer ) ; an epoxy amine resin - based sealer . after obturation , all the specimens were stored at a temperature 37c for duration of 24 h to allow complete setting of the sealer . proximal radiographs of each specimen ( kodak rvg 6100 ; kodak dental systems , atlanta , ga , usa ) were taken using the spectro 70 electronic x - ray unit after standardizing the positioning of the roots and the focus - film distance . then , specimens were soaked once again in methyl salicylate , and standardized digital photographs were taken ( nikon d80 ; nikon , tokyo , japan ) . the radiographic and photographic images showing the root canal fillings in each specimen were imported into the image tool software ( uthscsa image tool for windows version 3.0 , san antonio , tx , usa ) . the amount of filling material observed in each lateral canal at the level of 2 , 4 and 6 mm was calculated by single calibrated examiner . the data were expressed as linear extension ( length in mm of the lateral canal that was filled in relation to its entire length ) and of the area filled ( area in millimeter square occupied by the filling material inside the lateral canal in relation to its entire area ) . the cbct scans were done using promax 3d mid ( planmeca oy helsinki , finland ) . the samples were mounted on wax block for stabilizing them and were exposed to the cbct scans with 90 kv and 8 ma with field of view of 4.5 cm  4.5 cm and an isotropic resolution of 2 mm resulting in 400 - 450 slices per tooth with exposure time of 12.28 s. table 1 shows the radiographic analysis of each material of filled the simulated lateral canals ( measured in linear and area percentages ) . smartseal system of obturation when evaluated , presented a high mean ( 89.45  16.21 ) in linear extension of root canal and high mean of ( 92.46  19.45 ) in area filled . pro - points demonstrated a greater filling ability ( p < 0.05 ) than gutta - percha in all thirds of canal , as shown by the radiographic analysis ( extension and area ) , and as by the analysis of cleared specimens ( extension ) . figure 2 shows the cbct analysis ( axial sections ) of all groups , in coronal ( a ) , middle ( b ) and apical ( c ) sections . polyamide polymer reveals minimum voids in all sections indicating an obturation of greater homogeneity in comparison to gutta - percha system . mean percentage of linear extension and area extended in coronal , middle and apical root canal photographic and radiographic analysis . ( c ) cold lateral condensation ( control ) cone beam computed tomography analysis ( axial sections ) . ( c ) apical section  ( a ) polyamide polymer obturation , ( b ) sectional backfilled obturation , ( c ) cold lateral obturation ( control ) the ultimate goal of obturation is to prevent the re - infection of root canals that have been biomechanically cleaned , shaped and disinfected by instrumentation and irrigation . successful obturation requires the use of materials and techniques capable of densely filling the entire rcs and providing a fluid tight seal from the apical segment of the canal to the canal orifice in order to prevent re - infection . therefore , the goal of 3d obturation is to achieve an impermeable fluid tight seal within the entire rcs which will further help in preventing oral and apical microleakage . gutta - percha along with root canal sealers is the worldwide accepted combination available till date and is considered as the gold standard . despite its many advantages and having achieved the status of a high quality material , gutta - percha still has its limitations like its inability to strengthen root as it does not bond to dentin . although few materials have seriously challenged gutta - percha in the majority of aspects associated with gutta - percha , research continues to find alternatives that may seal better and mechanically reinforce compromised roots . the major demerit seen with gutta - percha is its inability to reinforce endodontically treated tooth . gutta - percha does not chemically bond to the dentin wall , that is , does not form the monoblock system . according to teixeira and trope . gutta - percha does not from a monoblock even with the use of a resin - based sealer such as ah plus because the sealer does not bind to gutta - percha . moreover , the sealer tends to pull away from the gutta - percha on setting . thus , the ultimate goal of this study was to search an alternative to currently and most widely used gutta - percha system which would not only have the ideal characteristics of gutta - percha , but also further new advances installed . smartseal system consists of polyamide polymer cones ( propoints ) and a resin sealer with additional polymer powder to be mixed during manipulation of the sealer . the white points consist of a radiopaque core coated with a radiopaque hydrophilic polymer , which can expand laterally upon absorbing water from the tooth , adopting the shape of the canal . the points can expand up to around 17% and will still give the same x - ray appearance as with conventional root - filling materials . leakage studies indicate single - cone obturation methods to be inferior in their ability to achieve a fluid - tight seal . the use of expandable obturating materials to improve the seal of the root - filled canals have been reported even for gutta - percha . gutta - percha expands in the presence of eugenol , which may reduce gaps within the filled canal space . apart from eugenol - induced expansion , closure of microgaps in gutta - percha filled root canals by moisture present within the canal space may compensate for leakage that arises from sealer dissolution to certain extent the delayed hygroscopic expansion of pro - points when latter is coated with a hydrophobic sealer that impedes water sorption may partially compensate for the gaps arising from sealer dissolution . farge et al . showed that lateral condensation technique results in more leakage than thermomechanical compaction technique . brothman et al . reported that the thermoplasticized condensation technique on radiographic examination , shows nearly 2 times more lateral and accessory canals compared with lateral condensation technique . the amount of filling achieved in the lateral canals of natural teeth has been evaluated by means of radiographs and visual analysis of decalcified and cleared specimens following a protocol described by venturi et al . venturi et al . evaluated the diameter and shape of natural lateral canals as well as the ability of different root canal filling materials to fill these root canals using three obturation techniques . in this study , the lateral canal preparation was held after the demineralization of teeth until they achieved a rubber - like consistency . the # 8 or # 10 k - files were inserted into the softened root creating standardized artificial lateral canals at 2 , 4 and 6 mm from the apex . the clearing procedure was then completed by immersion in methyl salicylate to harden the specimens and restore their initial consistency . the radiographic analysis was performed digitally and the specimens had been previously subjected to the decalcification and clearing protocol promoting better image quality . this study has shown results that polyamide polymer has shown a greater area and linear extension occupied in the root canal space as compared to obturation techniques using gutta - percha . such a result can be attributed to the hygroscopic expansion property exhibited by the polyamide polymer system and the shrinkage associated with the gutta - percha system . even though , the sealers are mostly responsible for obtaining a proper seal in the lateral canals and attempt was made to show the role of different obturation techniques in filling simulated lateral canals as well as the role of a hydrophobic and a hydrophilic obturating system . an outstanding review by taylor et al . have reported on many possible endodontic application of cbct , simon et al . however , for this in vitro study , for the analysis of newer obturating material cross - sectional analysis using cbct was done to evaluate the homogeneity . as group a was obturated using a single - cone technique , it can be hypothesized that it would show greater homogeneity as compared to lateral condensation and sectional backfilled methods . as seen in the images lesser number of voids is observed in the cross - section of group a owing to its greater homogeneity ; leading to better adaptation in the root canal space . even though one can contradict the use of cbct image analysis for postobturation evaluation as various artifacts like scattering are associated with cbct image analysis , which can be mistaken for potential voids in the obturation . however considering the enormous benefits this cost - effect can be overlooked since the ease of the machine makes it suitable to be used also in minor diagnostic procedures . furthermore , analysis would be required to evaluate the actual expansion shown by the polyamide polymer system ; its microleakage properties , fracture toughness , and bond strengths to the dentin . with the introduction of novel hydrophilic smartseal system over the conventional hydrophobic gutta - percha system , has widened our range of achieving a 3d seal . this study concludes a greater efficiency in filling simulated lateral canals and a comparable homogeneity of obturation using smartseal system over gutta - percha .
aim : the aim was to evaluate and compare a novel polyamide polymer based obturating system and gutta - percha and sealer in filling simulated lateral canals and their homogeneity when used for obturating the root canals.materials and methods : a total of 60 freshly extracted human single rooted teeth with fully formed apices were selected for this study . 
 teeth were de - coronated , and roots were standardized to a working length of 15 mm . 
 root canal preparation was carried out with rotary protaper file system in all groups . 
 the specimens were then randomly divided into three groups a , b , and c ( n = 20 ) . 
 ten samples from each group were decalcified and simulated lateral canals were made at 2 , 4 , and 6 mm from the root apex . 
 remaining ten samples from each group were maintained calcified . 
 group a was obturated with smartseal system ( prosmart - drfp ltd . , stamford , uk ) . 
 group b was obturated with sectional backfill method . 
 group c was obutrated with cold lateral compaction method ( control ) . 
 decalcified samples from the respective groups were analyzed with digital radiography and photography and the measurement of the linear extension and area of lateral canal filling was done using uthscsa ( uthscsa image tool for windows version 3.0 , san antonio , tx , usa ) software . 
 calcified samples were subjected to cone beam computed tomography image analysis sectioned axially.results:group a 92.46  19.45 showed greatest extent of filling in lateral canals and denser homogeneity of oburation , followed by group b 78.43  26.45 and group c 52.12  36.67.conclusions:polyamide polymer obturation proved to have greater efficiency when compared with gutta - percha system , when used for obturation with regards to adaptation of the sealer and penetration into the simulated lateral canals .