This document provides information about the anatomy and root canal treatment of the mandibular second premolar tooth. It describes the external and internal anatomy of the tooth, including average measurements, root canal morphology, and anatomical variations that may be present. It also discusses errors that can occur during root canal treatment of this tooth and provides a case example of successfully treating a mandibular second premolar with three root canals.

1. MANDIBULAR 2 PRE MOLARBYO.R.GANESH MURTHI M.Sc.D ENDO

2. OUT LINE INTRODUCTION

3. EXTERNAL ANATOMY

4. INTERNAL ANATOMY

5. VARIATIONS

6. ANOMALIES

7. ENDODONTIC CORRELATION

8. INTRODUCTION The term premolar is used to designate any tooth in the permanent dentition that replaces a primary molar.fifth tooth from midline in the mandible quadrant. They assist canine in shearing and support corners of the mouth from sagging.

9. Mandibular 2nd premolarAverage time of eruption : 11 to 12 yearsAverage age of calcification : 13 to 14 yearsAverage length : 22.3 mm

10. Significance of average time of eruption,ageof calcification,toothlength & root curvature: IT HELPS IN DIAGNOSIS AND TREATMENT PLAN TREATMENT IS DIFFERENT IN ADULT AND YOUNGNECROTIC PULPRCTADULT IRREVERSIBLE PULPITIS

11. YOUNGIrreversible Pulpit's Necrotic PulpReversible Pulpit'sPulp Capping or PulpotomyClosed ApexOpen ApexApexification ObturationApexogenesisRCT

12. Mandibular 2nd premolarAverage Length : 21.4 mm Maximum Length : 23.7 mmMinimum Length : 19.1 mmRange : 4.6 mm

13. Mandibular 2nd premolarIMPORTANCE It helps in the determining the working length and better assumption of the radiographConsideration must be given to the mental foramen which lies in close proximity to the apex. Avoid over instrumentation and overfill.

14. Mandibular 2nd premolarBuccal aspectLong pointed buccal cusp in the occlusal profileMesial cusp ridge is shorter than distal Cusp tip is a little mesial to the tooth midline

15. Mandibular 2nd premolarBuccal aspectMesial & Distal outlines are markedly convergingCervical line is flat mesiodistal compared to that of canineRoot is conical with pointed apex

16. Mandibular 2nd premolarLingual aspectmesiodistal diameter = that from Buccal aspectOcclusal surface cannot be seen fullyOcclusal plane is perpendicular to tooth Axis

17. Mandibular 2nd premolar2 lingual cusps (most commonly) • Mesiolingual – major, 2/3 MD diameter, same height as Buccal • Distolingual – minorLingual groove2/3

18. Mandibular 2nd premolarMesial aspectTriangular ridges of Buccal and Mesio lingual cusps don’t not form a continuous crestDistal aspectBoth lingual cusps are seen

19. Mandibular 2nd premolarOcclusal aspectSquare profile Mesial & Lingual profiles are parallelMore than half of Buccal surface is visibleBuccal ridge is less prominent than that of mandibular 1st premolarMesial & Distal Marginal ridges are equal in length

20. Mandibular 2nd premolarOcclusal viewMesial & Distal triangular fossaeeach contains• A pit• Mesiobuccal & Distobuccal groovesMD

21. Mandibular 2nd premolarOcclusal viewGrooves (Y shape meet at the central pit)• Mesial groove separates Buccal & Mesiolingual triangular ridges – runs obliquely• Lingual groove separates lingual cusps• Distal groove separates Buccal & Distolingual triangular ridgesBMLDL

22. Mandibular 2nd premolarPulp Buccolingual section• Pulp chamber iswider• Pulp horns are ofequal height

23. Mandibular 2nd premolarPULP CHAMBER Mesiodistal width - narrow

24. Buccolingual width - wide

25. Lingual horn is more prominent under a well developed lingual cusp 30 lingual tilt

26. Cross section – ovoid with greater diameter in buccolingually

27. Mandibular 2nd premolar

28. Mandibular 2nd premolarROOTS AND ROOT CANALSThe Mandibular second premolar resembles the first premolar, but the lingual canal is present only occasionally.The root canal is oval in cross-section and rather straight with only a slight distal curvature in some canals

29. Mandibular 2nd premolarROOTS AND ROOT CANALS

30. Mandibular 2nd premolarROOTS AND ROOT CANALS1 Canal 1 foramen - 85.5 %1 canal 2 foramen - 11.5 %2 Canal 1 foramen - 1.5 %3 canal - 0.5 %Distal curve – 40 %Straight – 39 %Buccal curve – 11 %Lingual curve – 10 %

31. ROOTS AND ROOT CANALSOne root canal dividing in to two at apexSingle canal that has divided and cross over at the apex

32. ROOT CANAL ORIFICES 1 CANAL SEPARATE INTO 2 CANALSDIVISION IS BUCCAL AND LINGUALLINGUAL CANAL SPLITSFROM THE MAIN CANALAT SHARP ANGLE IT IS VISUAL CONFIGURATION AS LOWER CASE LETTER hBUCCAL CANAL IS STRAIGHTPORTION OF THE h

33. ACCESSORY CANALSMostly found in the apical third Lateral canals may be found in 44.3% cases Usually a good biomechanics preparation cleanses the canal well and is filled with the sealer during Obturation.The ability to cleanse and seal these canals have an impact on the prognosis

34. Mandibular 2nd premolarNote :• When only one canal is present , it is usually found in the center of the access preparation. If only one canal is found, but it is not in the centre of the tooth, it is probable that another canal is presentROOT CANAL ORIFICES 1 CANAL PRESENTLOCATED IN THE CENTER OF THE ACCESS PERPARATIONNOT LOCATED IN CENTEROF THE ROOTANOTHER ORIFICES PROBELY EXISTSCLINICIAN SHOULD SEARECH FOR OPPOSITE SITE

35. Mandibular 2nd premolarAnatomic relationships in situThe mental canal and foramen are close to the root apex Radiograph appearance may shows peiapical pathosis

36. Anatomic relationships in situAvoid over instrumentation and overfill When viewing an x-ray of this area, the mental foramen is sometimes misdiagnosed as a premolar abscess. Therefore, before performing root canal therapy, make sure all diagnostic tests confirm your finding.

37. FAST BREAK When numerous canalare present, the preoperative radiograph often indicates a "fast break." This appears as a relatively patent canal space in the coronal portion of the tooth that suddenly disappears.

38. FAST BREAKNote: If a straight-on preoperative radiograph of a Mandibular 2 premolar shows the pulp canal disappearing in mid-root, this is an important indication that two canals are present.

39. Mandibular 2nd premolarThe mandibular second premolar is similar to the first premolar, with the following differences: The lingual pulp horn usually is larger The root and root canal are more often oval than round The pulp chamber is wider buccolingually

40. THE ACCESS CAVITY The access cavity form for the Mandibular second premolar varies in at least two ways in its external anatomy.1.The crown typically has a smaller lingual inclination less extension up the buccal cusp incline is required to achieve straight-line access. 2. The lingual half of the tooth is more fully developed; therefore the lingual access extension is typically halfway up the lingual cusp incline.

41. THE ACCESS CAVITY The Mandibular second premolar can have two lingual cusps, sometimes of equal size. When this occurs, the access preparation is centered mesiodistally on a line connecting the buccal cusp and the lingual groove between the lingual cusp tips.

42. THE ACCESS CAVITY Buccolingual ovoid outline form reflects the anatomy of the pulp chamber and position of the centrally located canal.

43. THE ACCESS CAVITY The lingual portion should be prepared well for a straight line access and location of lingual canal.CROSS SECTIONAL IN CERVICAL LEVELthe pulp is large in a youngtooth, very wide in the Buccolingual dimension.Debridement of the chamber is completed during coronal cavity preparation with a round bur

44. CROSS SECTIONAL IN MIDROOT LEVEL AND APICALMidroot level: the canal continues to be long ovoid and requires perimeter filing Apical third level: the canals, generally round, are shaped into round, tapered preparations.Preparation terminates at the cementodentinaljunction, 0.5 to 1.0 mm from the radiographicapex.

45. MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATIONPERFORATIONat the disto gingival caused by failure to recognize that the premolar has tilted to the distal

46. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATIONINCOMPLETEpreparation and possible instrument breakage caused by total loss of instrument control. Use only occlusal access, never buccal orproximal access.

47. MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATIONBIFURCATIONOf a canal completely missed,caused by failure to adequately explore the canal with a curved instrument

48. MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATIONAPICAL PERFORATIONOf an invitingly straightconical canal. Failure to establish the exact length of the tooth leads to trephination of the foramen

49. MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATIONPERFORATION at the apical curvature caused by failure to recognize, by exploration, buccal curvature.A standard bucco lingual radiograph will notshow buccal or lingual curvature

50. Mandibular 2nd premolarAnomalies Dens invaginatus

51. Dens evaginatus

52. Gemination

53. Dilaceration DENS INVAGINATUS Dens invaginatus is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. Affected teeth show a deep infolding of enamel and dentine. Occurs before calcification of the teeth. Also known as dens in denteTREATMENT OF DENS INVAGINATUSThe treatment modalities depend on the degree of complexity of its anatomy.

54. They include nonsurgical endodontic treatment, endodontic surgery and extraction.

55. In cases in which there is an immature apex, calcium hydroxide is used to stimulate apexificationDENS EVAGINATUSDens evaginatus is a developmental anomaly that manifests as a tubercle emerging from the surface of the affected tooth.

56. It occurs most frequently in the premolars.

57. Higher prevalence among people of Mongoloid origin.DENS EVAGINATUS

58. Clinical importanceFracture or wear of the tubercle could lead to pulp necrosis before root formation is complete.

59. Various prophylactic treatments like selective grinding, application of resin, restorations and partial Pulpotomy can be done.

60. If there is complete pulpal necrosis in an immature tooth, MTA can be used in the apex followed by endodontic treatment.Mandibular second premolar with three root canalsReport of a case