6. are often weakened coronally by excessive removal of tooth structure is often narrower than the bur used to make the initial access. (cervical or root surface) are common, especially with calcifications.

7. A, Sweeping motion in a slightly downward lingualto- labial direction (arrows), until the chamber is engaged, to obtain the best access to the lingual canal. B, Incorrect approach:directing the end-cutting bur in a straight lingual-tolabial direction. Mutilation of tooth structure and perforation will be the result in this small and narrow incisor.

13. Double lateral canals Curved accessory canal with straight lateral canal intersecting. Parallel accessory canal to main canal with simple lateral canal.

14. Average time of eruption: 8 to 9 years Average age of calcification: 11 years Average length: 22.0 mm

16. Average time of eruption: 10 to 12 years Average age of calcification: 13 to 15 years Average length: 26.5 mm

18. Canine with multiple accessory foramina. Maxillary canine with lateral canal dividing into two additional canals.

20. Average time of eruption: 10 to 11 years Average age of calcification: 12 to 13 years Average length: 20.6 mm

23.  Pulp horns appear blunted.  Pulp chamber can’t be diffrentiated from root canal.  Pulp cavity tapers slightly from occlusal aspect to to apical foramen.  Apical foramen often exit at tip of root, or some at mesial or distal sides.

26.  Shows the characteristic kidney shaped outline due to the M developmental groove.  Pulp cavity may show constriction adjacent to developmental groove, or may follow outline of root surface.  Some roots will show 2 separate root canals or 3 in case of 3 rooted root canals.

28. Three canals in maxillary first bicuspid. Two canals fusing and rcdividing. Lateral bony lesion associated with filled lateral canal

29. Average time of eruption: 10 to 12 years Average age of calcification: 12 to 14 years Average length: 21.5 mm

32.  Some teeth process dentinal islands or bifurcations at the apical third of the root, the clinician must treat this situation as 2 roots.  The apical foramen may exit at the root tip, at buccal or lingual aspects of the root, or at both buccal & lingual aspects.

33.  Pulp horns are blunt, Pulp cavity tapers slightly from occlusal aspect to apex.  Apical foramen may exit at root tip or anywhere near it.

34.  Is oval or kidney shaped.  Pulp cavity is either centered in the root, may be constricted in the middle of the canal space, elliptical or entire seperation.

36. Multiple foramina. Single canal dividing into two canals. Single canal splitting into three canals.

37. Average time of eruption: 6 to 7 years Average age of calcification: 9 to 10 years Average length: 20.8 mm

39. Fourth canal in mesiobuccal root; loops and accessory canals Second canals in both mesiobuccal and lingual canals. Sharp curvature and multiple accessory canals in palatal root (contrast to silver cones in second molar).

40. Average time of eruption: 11 to 13 years Average age of calcification: 14 to 16 years Average length: 20.0 mm

42. Four-rooted maxillary second molar Severely curved mesiobuccal root with right angle curve in distobuccal root.

43. Average time of eruption: 17 to 22 years Average age of calcification: 18 to 25 years Average length: 17.0 mm

45. Showing canals fuses into single canal. (Note multiple accessories in second molar.) Distal bridge abutment with major accessory canal.

46. Average time of eruption: 6 to 8 years Average age of calcification: 9 to 10 years Average length: 20.7 mm

48. Two-rooted mandibular lateral incisor. Mandibular lateral and central, both with two canals.

49. Average time of eruption: 9 to 10 years Average age of calcification: 13 years Average length: 25.6 mm

51. Two-rooted mandibular canine Sharp distal curveture at apex Two lateral canals. The incisal canal is above the crest of bone and was probably responsible for pocket depth. Twincanaled mandibular canine with significant lateral canals feeding a periodontal defect

52. Average time of eruption; 10 to 12 years Average age of calcification: 12 to 13 years Average length: 21.6 mm

54.  Pulp horn is prominent  Pulp chamber & root canal taper gently to apex.  Apical foramen either exit from root tip, or around it.

56.  Outline form of root may be either oval, rectangular or triangular.  Pulp cavity may be round, elliptical, or triangular.  If bi or trifurcation exists, 2-3 round canals can be seen.

57.  Buccolingual Section  Pulp cavities are larger at crown & occlusal portion of root canal  2or 3 pulp horns can be seen  Apical foramen may exit at apex,at buccal or lingual aspect of root tip.

59.  Similar to mand 1 st.  Usually has one root & one root canal that may be curved in a distal direction.

60.  Outline form of root may be either oval, rectangular or triangular.  Pulp cavity may be round, elliptical, or triangular.

61. Three-rooted mandibular first bicuspid Single canal dividing at apex.

62. Average time of eruption: 11 to 12 years Average age of calcification: 13 to 14 years Average length: 22.3 mm