Endodontics

Maxillary first premolars with three root canals: case reportsEssam I. Zaatar* / Mona A, Al-Busairi** / M. Jawad Behbehani***

Awareness of normal and abnormal variation of the internal anatomy of the teethis essential for clinical success. Three cases in which maxillary premolars were found tohave three roots and the subsequetn endodontic therapy are described.(Quintessence Int 1990;21:1007-1011.)

Introduction

Modem endodontic therapy is based on debridement,disinfection, and obturation of the root canal system.Because of anatomic complexities, clinical treatmentis often difficult and time consuming. It has beenstated that anatomy is the foundation of the art andscience of healing'; therefore, the clinician should beaware of both normal and abnormal variations of theinternal anatomy of the teeth to achieve a high degreeof chnical success.

Many studies have been conducted to explore theroot canal system of maxillary first premolars. Themajority of these studies has been performed on ex-tracted teeth. The methods utilized include section-ing,-' grinding, "• roentgenographic examination,'^ fab-rication of plastic replicas,' and making transparentspecimens.* Results of these studies indicate that theincidence of maxillary first premolars with three rootcanals ranges between 0.5% and 6.0%." '̂'"^ Two stud-ies have faiied to report this incidence in their results,"'•'The only in vivo studies regarding the internal anat-omy of maxillary first premolars are those reportedby Belhzzi and Hartwell.''" They conducted a 10-yearchnical survey followed by a 13-year chnical survey ofendodontically treated maxillary first premolars andfound the incidence of three root canals to be 3.7%and 3.3%, respectively.

* Endodontisl. Ministry of Public Healtti, Dental Centre,PO Box 4077, Safal-Sharq Kuwait 1304t.

*• Praclice ¡imited lo Endodonlics, Ministry o( Public Heatlh." * Head of Endodontic Depurtnient, Ministry of Public Health.Because postal service to Kuwait has been suspended, ttie authorswere unable to review proof of this article.

The purpose of this article is to present three casesof three-rooted maxillary first premolars in which allroot canals were instrumented and obturated.

Case 1

A 34-year-old white man presented with a chief com-plaint of a recurrent small gingival abscess thatopened with a foul-smelhng discharge after severaldays. The patient stated that it was never painful, butthe condition had occurred approximately four timeswithin the last year. Radiographic examinationshowed that tooth 24 had an unusual configurationof roots and an ill-defined radiolucent area related totheir apices (Fig 1}. Chnical examination revealed asmall area of mesial decay that extended to the pulphorn. A sinus tract was detected and traced to thepalatal root of tooth 24 {Fig 2).

Results of vitahty tests on all teeth in the area werepositive except for the results on tooth 24, which didnot respond to chnical thermal tests or the electricpulp tester. The clinical diagnosis was of a necroticpulp with periradicular extension, indicating chronicsuppurative apical periodontitis. The medical historyof the patient was noncontributory.

Root canal treatment was initiated without anes-thesia. The tooth was isolated with rubber dam andthe access completed; no bleeding was observed in thepulpal chamber or from the canals.

The working-length radiograph revealed that thetooth had a third eanal that had been undetected(Fig 3). Further examination of the pulpal floor withsharp endodortic explorer revealed the third root can-al. The canals were designated as mesiobuccal, dis-

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Endodontics

Fig 1 Case 1. Preoperative radiograph reveals the un-usual root configuration.

Fig 2 Case 1. Radiograph showing gutta-percha conepointing to the palatai root ol the tooth 24.

Fig 3 Case 1. Radiograph showing tiles in distobuccai andpalatal root canals.

Fig 4 Case 1. Wori<ing-length radiograph showing files inthe three root canais.

Fig 5 Case 1. Immediately postobturation radiograph. Fig 6 Case 1. Radiograph taken 2 years after obturation.Complete osseous repair has taken place.

Fig 7 Case 2. Preoperative radiograph showing both max-illary premolars with three roots.

Fig 8 Case 2. Working-length radiograph showing twobuccai canais and one palatal canai.

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Endodonties

Fig 9 Case 2. Immediately postobturation radiograph. Fig 10 Case 2. Six-month recall radiograph reveals an in-tact lamina dura.

tobuccal, and palatal root canals. Another working-length radiograph was taken (Fig 4). Instrnmentationwas carried out with a step-back filing technique," and2.25% sodium hypochlorite was used as an irrigatingsolution. Gates-Glidden drills were used to flare thecoronal one third of each canal to allow obturationwith a warm gutta-percha vertical condensation tech-nique.'- The access opening was sealed with dry cottonand Cavit (ESPE GmbH). Ten days postoperatively,the patient presented asymptomatically, and the sinustract had elosed. Obturation of the canals was carriedout using gutta-percha and Pulp Canal Sealer (Ken/Syhron Corp) (Fig 5),

When the patient was recalled periodically he re-ported no symptoms of recurrence. The 2-year recallradiograph showed complete osseous repair (Fig 6}-

Case 2

A 29-year-old white man was referred to the Endo-dontic Department for completion of endodontictreatment on tooth 24. Pulpectomy had heen per-formed by the referring dentist, who stated that thetooth had an irreversibly inflamed pulp as a result ofadvanced decay. Examination of the preoperative ra-diograph revealed that the left maxillary first and sec-ond premolars both had three roots (Fig 7), The pa-tient was also advised of the need for dental treatmenton tooth 27, which had proximal decay. The medicalhistory ofthe patient was noncontributory.

The tooth was anesthetized and isoiated with a rub-ber dam. The provisional restauration was removedand access completed. A radiograph was taken whilethe files were in place in the three canals (Fig 8). andinstrumentation was completed using a step-back fil-

ing technique." The canals were frequently irrigatedduring instrumentation with 2,25% sodium hypo-chlorite solution. There were no eontraindicationsto obturating the canals at the same appointment.Gutta-percha, Pnlp Canal Sealer, and the lateralcondensation technique were used. The postobtura-tion radiograph (Fig 9) revealed some voids at thecoronal one third of the canals that were thought tobe insignificant to the prognosis- The patient wasreferred to his general dentist for final restoration ofthe tooth.

A 6-month recall examination of the patient re-vealed that the tooth was asymptomatic and gave noevidence of peri radicular pathosis (Fig 10).

Case 3

A 24-year-old white man was referred to the Bndo-dontic Department for treatment of tooth 14. Priorto referral, the patient had received emergency treat-ment that consisted of excavation of caries, pulpec-tomy, and placement of dry cotton and a provisionalrestoration.

The patient reported that he had been experiencingsevere sensitivity to cold and sweet food and drinks.The symptoms disappeared after emergency treatmentwas received.

Treatment procedures were similar to that used forthe patient in case 1, except that the patient reportedslight intermittent discomfort and tenderness to per-cussion that lasted for 3 days after the instrumentationvisit. Preoperative and postobturation radiographs re-vealed that the tooth had three root canals (Figs 11and 12).

The patient failed to respond to the recall system.

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Endodontics

Fig 11 Case 3. Preoperative radiograph. Fig 12 Case 3. Immediately postobturation radiograph.

Discussion

Variations of internal anatomy of teeth are well doc-umented in the literature. Failure to recognize thisprinciple may reduce the success rate of nonsurgicalendodontic therapy. The primary way to determineroot canal morphology clinically before nonsurgicalendodontic therapy is to obtain properly angulatedradiographs and examine them carefully. Unfortu-nately, intraoral radiographs only provide a two-dimensional image of three-dimensional root canalsystem.** Therefore, consideration should be givento obtaining adequate preoperative radiographs atvarious horizontal angulalions whenever an unusualroot configuration is detected. This will provide aclearer view of the tooth image.

The orifice location of the teeth in these patientsresembled small maxillary second molars. Their dis-tobticcal root canals were located more toward themesial and to the palatal of the tooth (Fig 13). Allteeth showed typical clinical crown morphology ofmaxillary first premolars.

Of the two buccal canals, the distobuccal canal wasalways found first. It was concluded that a slight mod-ification of the regular ovoid-shaped access openingof the tooth was necessary to locate, instrument, andobturate all three canals successfully (Fig 13). Thepresence of an extra canal should be suspected when-ever an instrument demonstrates an eccentric direc-tion on deeper penetration into the canal, termeddirectional conirol as reported by Green.''

At the time of obturation in these three patients, itwas decided to obturate one canal at a lime because

MRC. ^ 'i

\

DBC

Pr.

Fig 13 Access preparations and oritice location; (A) reg-ular access; (B) modified access; (MBC) mesiobuccal canal;(DBC) distobuccal canal; (PC) palatal canal.

of the limited accessabihty. The pulp chambers weretoo small to harbor three gutta-percha points.

Failure, after apparently adequate convetitional en-dodontic treatment of maxillary first premolars, maysometimes be attributed to the presence of an unde-tected third root canal. Therefore, every effort shouldbe made to exclude the presence of an extra canal.

Summary

The treatment of three patients who presented withthree-rooted maxillary first premoiars is reported. Allcanals were instrumented and obturated. Althoughthe condition is not common, the clinician should befamiliar with such variations to ensure clinical success.

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Endodontics

References

1. Kuttler Y: Microscopic investigation of root apexes. J . 4 H Í Z ) ™ ÍAssoe 1955;50:544-552,

2. HessW: Anatomy of the Root Canals of the Teelh of PermanentDentition. New York, William Wood and Co. 1927, pp 29-30.

3. Barrett MT: The internal atiatomy of teeth with special referenceto the pulp with its branches. Dent Cosmos 1925:67:581-592.

4. Green D: Double canals in single roots. Oral Surg Oral MedOral Pathol 1973;35:689-696

5. Mueller AH Anatomy of the root canals of the incisors, cuspidsand bicuspids of the permanent teeth. J Am Deni Assoe1933;20:1361-1386.

6. Pineda F. Kuttler Y: Mesiodistal and buccolingual roeutgeno-graphic investigation of 7,275 root canals. Oral Surg Oral MedOral Palhol 1972;33:101-110.

7, Cams EJ, Skidmore AE: Configurations and deviations of rootcanals of masillary first premolars. Oral Surg Oral Me/I Oral

Pathol 1973;36:880-S86.

K. Vertucci KJ, Gegauff A: Root canai morphology of the mas-illary first premolar. J Am Dem Assoc 1979.99:194-198

9. Bellizzi R, Hartwell G: Evaluating the maxillary premolar withthree canals for endodontic therapy, J EnJodunt 1981;8:52]-527,

10. Bellizzi R, Hartwell G: Radiogmphic evaluation of root canalanatomy of in vivo endodontically treated maxillary premolars.J Endodont 1985:11:37-39.

11. Ingle Jl, Taintor JP (eds): Endodontics. Philadelphia, Lea &Febiger. 1985, pp 201, 136,

12. Schilder H: Filling root canals in three dimensions. Dent ClinNorlh Am 1957;(Nov¡:723, D

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