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 MOLAR BY O.R.GANESH MURTHI M.Sc.D ENDO

3. EXTERNAL ANATOMY

4. INTERNAL ANATOMY

5. VARIATIONS

6. ANOMALIES

7. ENDODONTIC CORRELATION

9. Mandibular 2nd premolar Average time of eruption : 11 to 12 years Average age of calcification : 13 to 14 years Average 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 YOUNG NECROTIC PULP RCT ADULT IRREVERSIBLE PULPITIS

11. YOUNG Irreversible Pulpit's Necrotic Pulp Reversible Pulpit's Pulp Capping or Pulpotomy Closed Apex Open Apex Apexification Obturation Apexogenesis RCT

12. Mandibular 2nd premolar Average Length : 21.4 mm Maximum Length : 23.7 mm Minimum Length : 19.1 mm Range : 4.6 mm

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

14. Mandibular 2nd premolar Buccal aspect Long pointed buccal cusp in the occlusal profile Mesial cusp ridge is shorter than distal Cusp tip is a little mesial to the tooth midline

15. Mandibular 2nd premolar Buccal aspect Mesial & Distal outlines are markedly converging Cervical line is flat mesiodistal compared to that of canine Root is conical with pointed apex

16. Mandibular 2nd premolar Lingual aspect mesiodistal diameter = that from Buccal aspect Occlusal surface cannot be seen fully Occlusal plane is perpendicular to tooth Axis

17. Mandibular 2nd premolar 2 lingual cusps (most commonly) • Mesiolingual – major, 2/3 MD diameter, same height as Buccal • Distolingual – minor Lingual groove 2/3

18. Mandibular 2nd premolar Mesial aspect Triangular ridges of Buccal and Mesio lingual cusps don’t not form a continuous crest Distal aspect Both lingual cusps are seen

19. Mandibular 2nd premolar Occlusal aspect Square profile Mesial & Lingual profiles are parallel More than half of Buccal surface is visible Buccal ridge is less prominent than that of mandibular 1st premolar Mesial & Distal Marginal ridges are equal in length

20. Mandibular 2nd premolar Occlusal view Mesial & Distal triangular fossae each contains • A pit • Mesiobuccal & Distobuccal grooves M D

21. Mandibular 2nd premolar Occlusal view Grooves (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 ridges B ML DL

22. Mandibular 2nd premolar Pulp Buccolingual section • Pulp chamber is wider • Pulp horns are of equal height

24. Buccolingual width - wide

26. Cross section – ovoid with greater diameter in buccolingually

27. Mandibular 2nd premolar

28. Mandibular 2nd premolar ROOTS AND ROOT CANALS The 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 premolar ROOTS AND ROOT CANALS

30. Mandibular 2nd premolar ROOTS AND ROOT CANALS 1 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 CANALS One root canal dividing in to two at apex Single canal that has divided and cross over at the apex

32. ROOT CANAL ORIFICES 1 CANAL SEPARATE IN TO 2 CANALS DIVISION IS BUCCAL AND LINGUAL LINGUAL CANAL SPLITS FROM THE MAIN CANAL AT SHARP ANGLE IT IS VISUAL CONFIGURATION AS LOWER CASE LETTER h BUCCAL CANAL IS STRAIGHT PORTION OF THE h

33. ACCESSORY CANALS Mostly 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

35. Mandibular 2nd premolar Anatomic relationships in situ The mental canal and foramen are close to the root apex Radiograph appearance may shows peiapical pathosis

36. Anatomic relationships in situ Avoid 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 BREAK Note: 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.

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.

44. CROSS SECTIONAL IN MIDROOT LEVEL AND APICAL Midroot 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 cementodentinal junction, 0.5 to 1.0 mm from the radiographic apex.

45. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION PERFORATION at the disto gingival caused by failure to recognize that the premolar has tilted to the distal

46. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION INCOMPLETE preparation and possible instrument breakage caused by total loss of instrument control. Use only occlusal access, never buccal or proximal access.

47. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION BIFURCATION Of a canal completely missed, caused by failure to adequately explore the canal with a curved instrument

48. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION APICAL PERFORATION Of an invitingly straight conical canal. Failure to establish the exact length of the tooth leads to trephination of the foramen

49. MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION PERFORATION at the apical curvature caused by failure to recognize, by exploration, buccal curvature. A standard bucco lingual radiograph will not show buccal or lingual curvature

51. Dens evaginatus

52. Gemination

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

56. It occurs most frequently in the premolars.

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

61. A 20- year-old male with non contributory medical history was referred to the clinics of the SaudiBoard in Advanced Restorative at the Faculty of Dentistry, for evaluation of root canal therapy of a mandibular 2 premolar. Clinical examination revealed that the tooth responded positively to percussion but not to palpation. Radiographic examination revealed short and inadequate root canal filling

62. Pre-operative radiograph showing the poor root canal filling.

63. The tooth was isolated with rubber dam, the old amalgam filling was removed and the access cavity preparation was established. Three canals were located, buccally, lingually and an extra canal in the middle. The working length was checked radiographically

64. Working length radiograph showing files in the three root canals.

65. The canals were conventionally instrumented to a # 35K file using crown-down pressureless technique, irrigated with 5.25 percent sodium hypochlorite, dried with sterile paper points and sealed with calcium hydroxide paste The access opening was closed with Cavit. The patient returned asymptomatic after 1 week, the tooth was isolated with rubber dam; the canals were instrumented with file #35 and irrigated with sodium hypochlorite to remove all the remnants of the calcium hydroxide, and then dried with paper points

66. Master cone was selected and the canals were filled with gutta-percha and AH26 sealer cement using lateral condensation. Access opening was sealed with amalgam restoration. Post-operative radiograph was taken to confirm the quality of the filling .The patient was referred to the prosthetic clinic for crown construction.

67. Obturation of the three root canals

68. DISCUSSION Location and thorough instrumentation of all the canals in the root of a diseased tooth normally ensure success of the endodontic therapy. Presented is a case of mandibular second premolar which was referred for endodontic therapy. Clinical and radiographicexamination revealed inadequate root canal filling. Three canals were located. Endodontic therapy was performed under aseptic conditions

70. Pathways Of The Pulp 6th Edition - Cohen