indeed , the major causes of endodontic treatment failure are incorrect canal instrumentation , incomplete canal obturation , and untreated major canals .
additional canals may be detected by clinical investigation of the floor of the pulp chamber and radiographic examination of the roots .
the maxillary first premolar typically has two canals ( 64 - 88% ) and sometimes a single canal ( 9 - 36% ) .
three - rooted maxillary first premolars are uncommon ( 0.5 - 1% ) and are similar to that of adjacent maxillary molars , and are referred to as  small molars  or  radiculous  .
mandibular second premolar has one root canal at the apex in 97.5% and two canals in only 2.5% of the cases .
one promising noninvasive method of detecting these enigmatic variations involves the use of magnifying visual aids such as the operating microscope , which offers homogeneous illumination and magnified view , to allow a clear visualization of the site .
we present here case series reports of rare variations in root canal configuration of the maxillary first premolar and mandibular second premolar and their management .
a 50-year - old indian male with a noncontributory medical history sought treatment at the department of conservative dentistry and endodontics , bapuji dental college and hospital , davangere karnataka , india .
his chief complaint was  pus drainage in the upper right back teeth region. clinical examination of soft tissues revealed a patent draining sinus tract in the labial alveolar mucosa in 14 region .
dental examination revealed deep class ii caries mesial occlusal ( mo ) with respect to the right maxillary first premolar , and radiographic examination revealed mesio - coronal radiolucency in close proximity to pulp chamber with diffuse periapical radiolucency [ figure 1a ] .
after excavation of caries and preendodontic management , entry into the pulp chamber was made , where 2 distinct canal orifices were found ( buccal and lingual ) .
gates glidden drills 4 , 3 , 2 , with a brushing motion were used in a crown - down fashion to enlarge the canal orifices .
, tochigi , japan ) using rc prep ( premier products co. ) as a lubricant .
a mild ledge like obstruction was felt at the cervical thirds of the buccal canal .
the working length iopar taken at an eccentric angle revealed that mesio - distal width of mid root was equal to that of crown and double periodontal ligament space ( distally ) was found in radiograph , which gave evidence of the presence of another root distally [ figure 1b ] . at this juncture ,
the access preparation was reevaluated under microscope and explored with dg-16 [ figure 1c ] .
the buccal end of the access was extended mesio - distally using an endo z bur ( dentsply ) in order to explore for the mesiobuccal or distobuccal orifices .
a distobuccal orifice was located and scouted with 10k file , which revealed an off - axis handle position .
working lengths were reconfirmed with apex locator and another working length iopar was taken revealing the mesiobuccal , distobuccal and palatal canals in vertucci 's type 5 with three roots configuration .
the canals were cleaned and shaped with hand k files and nickel titanium rotary files ( protaper , densply ) .
calcium hydroxide ( ultracal , ultradent ) was used as interappointment dressing for a period of 4 weeks , following which the canals obturated with standardized gutta - percha points [ figure 1d ] and ah plus sealer by lateral condensation technique [ figure 1e ] . a dual - cure composite resin ( luxacore z - dual , dmg ) postendodontic restoration was given .
the patient was followed - up regularly for 6 months , which revealed complete closure of sinus tract .
( b ) initial working length iopar taken at an mesial horizontal angulation , revealing a double periodontal ligament space ( distally ) giving a suspicion for an extra root .
( e ) obturation radiograph a 37-year - old indian male with a noncontributory medical history sought treatment at the clinic with a history of irreversible pulpitis .
dental examination revealed intact composite class 2 restorations ( mo and do ) with respect to left mandibular second premolar ( 35 ) .
radiographic examination revealed mesio - coronal radiopacity and a distocoronal radiopacity with underlying radiolucency in close proximity to pulp chamber [ figure 2a ] .
the preoperative iopar revealed a sudden disappearance of the main canal at middle one thirds of the root , indicative of splitting of root canals at that level . a radiolucent line running vertically from midroot level to the apex , indicated evidence of another root [ figure 2b ] .
( d ) obturation radiograph nonsurgical endodontic treatment was started for 35 and on entering the pulp chamber a large canal orifice was observed .
canal was carefully scouted using a 10k file where a buccal canal was easily located , while straight line access to the mesiolingual and distolingual canals were difficult .
hence , the access was reevaluated under microscope , and the main canal was enlarged using a peeso reamer 3 and 4 toward the lingual wall .
working length iopar taken with 15 k files revealed type ix root canal morphology according to sert and bayirli 's additional types to vertucci classification [ figure 2b ] .
the canals were cleaned and shaped with hand k files and hyflex cm rotary files ( coltne whaledent ) .
after drying the canals with paper points , they were obturated with laterally compacted gutta - percha and ah plus sealer [ figure 2c and d ] . at 1-month follow - up ,
a 50-year - old indian male with a noncontributory medical history sought treatment at the department of conservative dentistry and endodontics , bapuji dental college and hospital , davangere karnataka , india .
his chief complaint was  pus drainage in the upper right back teeth region. clinical examination of soft tissues revealed a patent draining sinus tract in the labial alveolar mucosa in 14 region .
dental examination revealed deep class ii caries mesial occlusal ( mo ) with respect to the right maxillary first premolar , and radiographic examination revealed mesio - coronal radiolucency in close proximity to pulp chamber with diffuse periapical radiolucency [ figure 1a ] .
after excavation of caries and preendodontic management , entry into the pulp chamber was made , where 2 distinct canal orifices were found ( buccal and lingual ) .
gates glidden drills 4 , 3 , 2 , with a brushing motion were used in a crown - down fashion to enlarge the canal orifices .
, tochigi , japan ) using rc prep ( premier products co. ) as a lubricant .
a mild ledge like obstruction was felt at the cervical thirds of the buccal canal .
the working length iopar taken at an eccentric angle revealed that mesio - distal width of mid root was equal to that of crown and double periodontal ligament space ( distally ) was found in radiograph , which gave evidence of the presence of another root distally [ figure 1b ] . at this juncture ,
the access preparation was reevaluated under microscope and explored with dg-16 [ figure 1c ] .
the buccal end of the access was extended mesio - distally using an endo z bur ( dentsply ) in order to explore for the mesiobuccal or distobuccal orifices .
a distobuccal orifice was located and scouted with 10k file , which revealed an off - axis handle position .
working lengths were reconfirmed with apex locator and another working length iopar was taken revealing the mesiobuccal , distobuccal and palatal canals in vertucci 's type 5 with three roots configuration .
the canals were cleaned and shaped with hand k files and nickel titanium rotary files ( protaper , densply ) .
calcium hydroxide ( ultracal , ultradent ) was used as interappointment dressing for a period of 4 weeks , following which the canals obturated with standardized gutta - percha points [ figure 1d ] and ah plus sealer by lateral condensation technique [ figure 1e ] . a dual - cure composite resin ( luxacore z - dual , dmg ) postendodontic restoration was given .
the patient was followed - up regularly for 6 months , which revealed complete closure of sinus tract .
( b ) initial working length iopar taken at an mesial horizontal angulation , revealing a double periodontal ligament space ( distally ) giving a suspicion for an extra root .
a 37-year - old indian male with a noncontributory medical history sought treatment at the clinic with a history of irreversible pulpitis . dental examination revealed intact composite class 2 restorations ( mo and do ) with respect to left mandibular second premolar ( 35 ) .
radiographic examination revealed mesio - coronal radiopacity and a distocoronal radiopacity with underlying radiolucency in close proximity to pulp chamber [ figure 2a ] .
the preoperative iopar revealed a sudden disappearance of the main canal at middle one thirds of the root , indicative of splitting of root canals at that level . a radiolucent line running vertically from midroot level to the apex , indicated evidence of another root [ figure 2b ] .
( d ) obturation radiograph nonsurgical endodontic treatment was started for 35 and on entering the pulp chamber a large canal orifice was observed .
canal was carefully scouted using a 10k file where a buccal canal was easily located , while straight line access to the mesiolingual and distolingual canals were difficult .
hence , the access was reevaluated under microscope , and the main canal was enlarged using a peeso reamer 3 and 4 toward the lingual wall .
working length iopar taken with 15 k files revealed type ix root canal morphology according to sert and bayirli 's additional types to vertucci classification [ figure 2b ] .
the canals were cleaned and shaped with hand k files and hyflex cm rotary files ( coltne whaledent ) . after drying the canals with paper points
, they were obturated with laterally compacted gutta - percha and ah plus sealer [ figure 2c and d ] . at 1-month follow - up ,
the possible anatomic configurations and their incidence of maxillary and mandibular premolars are well documented in the literature . for the first maxillary premolar ,
three - rooted maxillary premolars were reported to be an extremely rare variation in asian population ( 0.6% ) as compared to nonasian population ( 2.1% ) .
high - quality preoperative radiographs with different angulations ( 15 to 20 angle mesial or distal horizontal angle ) and their careful examination are essential for the detection of additional root canals .
when there is an abrupt straightening or loss of a radiolucent canal in the pulp cavity , an extra canal should be suspected in the same root or in the other independent roots .
whenever the mesio - distal width of the mid root region is equal to or greater than the mesio - distal width of the crowns , the tooth is likely to have extra roots . in the treatment of three - rooted maxillary premolar , two buccal orifices will usually be seen which are close to one another and difficult to locate .
hence , the access must be extended bucco proximally from the buccal orifice to cavosurface angles creating a t or triangular shaped access .
it is important to point out that the bifurcation of canals in the buccal root of maxillary first premolars often results in extremely thin and atresic canals , which are difficult to access , explore and obtain apical patency .
hence , shape of access and enlargement of coronal thirds is crucial , which was performed here with gates glidden ( gg ) drills , 1 - 4 and protaper s1 , s2 .
the minimum wall thickness was less on the palatal aspect ( < 1 mm ) than on the buccal aspect of the coronal two thirds of the buccal roots .
an anticurvature filing technique was used in this case toward the buccal aspect similar to buccal roots of maxillary molars .
studies have shown that the microscope increases the ability of the dentist to locate and negotiate the canal .
this case report shows the successful management of the maxillary premolar under magnification that was especially helpful for selective dentin removal and detecting the extra buccal orifice conservatively .
mandibular second premolars have a single root and a canal over 91% of the time .
an incidence of 0.4% for three canals in mandibular second premolar among 938 samples is previously reported .
the root canals in mandibular premolars are usually round , small and conical , but inclined to be ribbon - like in the cervical third of the root .
root canals may not be evident radiographically or may look unusual . in this case ,
root canal space disappeared halfway through the roots ( fast break ) indicating splitting of canal at midroot level .
however , up to 40 mesial angulation from horizontal is required to reliably identifying the extra canals .
careful interpretation of the periodontal ligament space may suggest the presence of an extra root or canal like in this case , where a tiny mesial root was observed , which appeared to be fused to the larger distal root .
this case would fall under category 5 ( three distinct canals with separate apices ) or more accurately type ix root canal morphology ( 1 main canal splitting into three canals with three separate apices ) . during the initial placement of scouting files
( hand k files 8 , or 10 ) in the main canal , obstruction was encountered , and the file deflected to the buccal or lingual before it traveled any further .
it was important , thereafter , to develop a sense of tactile feel and direction with appropriately precurved scouting files to detect the trifurcation .
probably , the greatest challenge in these kinds of cases is to identify them early so that appropriate modifications in treatment protocol , armamentarium to be used and the number of sittings can be planned .
 successful root canal therapy requires an accurate diagnosis and management of complex root canal morphology . 
 although the occurrence of three root canals in maxillary and mandibular premolars is very rare , the clinician must be able to identify it clinically and radiographically to make the necessary changes in his shaping and obturation techniques . 
 we present the endodontic management of a maxillary first premolar with three separate roots and canals , which was diagnosed with the aberrant anatomy only after the access preparation . 
 then , a mandibular premolar with three root canals and fused roots , which were diagnosed radiographically , is presented . 
 the necessary modifications of the routine clinical steps and the application of dental operating microscope for successful management of the complex anatomy , with emphasis on access modifications and radiographic interpretations are also explained . 
 teeth with extra roots and/or canals pose a challenge in clinical management . identifying them 
 early is necessary to facilitate appropriate modifications in treatment protocol , armamentarium to be used and plan optimal number of treatment sittings . 
INTRODUCTION
CASE REPORTS
Case 1
Case 2
DISCUSSION
CONCLUSION