The document discusses the anatomy and morphology of the apical third of teeth roots. It notes that this region is the most complex part of teeth and is important prognostically for endodontic procedures. The apical third can display variations like accessory canals, isthmuses, additional root canals and foramen, and curved or ribbon-shaped canal systems. These anatomical variations make cleaning, shaping, filling and surgery in this region challenging for endodontists. Proper instrumentation techniques and materials are required to navigate the complex apical third anatomy.

4. INTRODUCTION

5. mountains plains
the mountain pass
army front

7. 3000 permanent teeth minute details
like extensions, ramifications, branching as well
as size, shape and number of root canals in different teeth

8. Development of root
Hertwig’s epithelial root sheath.
size and shape of the root of the
tooth

10. horizontally
epithelial diaphragm
encloses delineates

11. , the epithelial diaphragm
HERS

12. single rooted teeth, single opening
double rooted teeth,
two openings.
three rooted teeth,
three openings
multi rooted

14. ACELLULAR CEMENTUM.
CELLULAR CEMENTUM
cementocytes.

15. coronal middle third of
root apical third of the root
apical third of the root
thicker than cervical third.

16. ACCESSORY CANAL FORMATION
inefficient source of collateral
circulation
• Defect in the epithelial root sheath
• Failure in the induction of dentinogenesis
• The presence of small blood vessels
more prevalent apical third
produce a gap -
accessory canal

18. ROOT LENGTH AND APICAL CLOSURE
dates of tooth eruption completion of
the root length apical closure

19. early in
females
maxillary posterior teeth are slightly later than mandibular teeth

20. TOOTH
INITIAL
MINERALISATION
ERUPTION ( INYEARS )
ROOT COMPLETION ( IN
YEARS )
MAXILLARY
1 3-4 months 7-8 10
2 10-12 months 8-9 11
3 4-5 months 11-12 13-15
4 11/2-13/4 years 10-11 12-13
5 2-21/4 years 10-12 12-14
6 At birth 6-7 9-10
7 21/2-3 years 12-13 14-16
8 7-9 years 17-21 18-25
MANDIBULAR
1 3-4 months 6-7 9-10
2 3-4 months 7-8 10
3 4-5 months 9-10 12-14
4 13/4-2 years 10-12 12-13
5 21/2-23/4 years 11-12 13-14
6 At birth 6-7 9-10
7 21/2-3years 12-13 14-15
8 8-10 years 17-21 18-25

21. TOOTH
ROOT COMPLETION ( IN
YEARS )
MAXILLARY
1 10
2 11
3 13-15
4 12-13
5 12-14
6 9-10
7 14-16
8 18-25
MANDIBULAR
1 9-10
2 10
3 12-14
4 12-13
5 13-14
6 9-10
7 14-15
8 18-25

22. funnel shaped opening
Ouostarinen et al 1966

23. ANATOMY OF ROOT APEX

24. Morphologically : most complex region
Prognostically : important part

26. APICAL CONSTRICTION
Physiologic foramen.

28. Morphology of the Physiological Foramen:I. Maxillary and Mandibular Molars VOL. 30, NO.5,MAY2004

29. ACCESSORY FORAMINA

30. CEMENTODENTINAL JUNCTION ( CDJ )
It is the point in the canal where cementum meets dentin

31. LOCATION & DIAMETER OF CDJ

32. THE DIAMETER OF THE CANAL

33. APICAL FORAMEN
Funnel shaped
Hyperbolic
Morning glory

35. • MEAN DISTANCE
• DIAMETER OF AF

36. EXIT OF AF

37. Number of apical foramen

38. • Size of apical foramen

39. Variations in morphology of apical third of the root & its
significance in endodontics

41. ACCESSORY CANAL

45. Accessory canals occur in three distinct patterns in the mandibular first molars.
A, In 13% a single furcation canal extends from the pulp chamber to the intraradicular region.
B, In 23% a lateral canal extends from the coronal third of a major root canal to the furcation region (80%
extend from the distal root canal).
C, About 10% have both lateral and furcation canals.

46. does not appear to be significant factor
granulation tissue

47. percentage of failures due to unfilled lateral canals is small
biological hard
closure of lateral canal foramina

48. Areas of resorption

51. PULP STONES / DENTICLES

54. VARIED AMOUNTS OF IRREGULAR
SECONDARY DENTIN

62. THIN “PINCHED” APEX
BULBOUS APEX

64. RESORBED APEX
BLUNDERBUSS APEX

66. Treatment of open apex with no vital pulp
Treatment of open apex with vital pulp
Pulpotomy is indicated to allow
completion of apical closure as long as
pulp remains vital – apexogenesis

68. TERMINATION POINT FOR ROOT CANAL
PROCEDURES

69. FROM THE APEX CONDITION
1mm No bone/root resorption
1.5mm Only bone resorption
2mm Bone & root resorption

73. CHALLENGES FACED DUE TO APICAL THIRD
ANATOMY DURING ENDODONTIC PROCEDURES

74. Mandibular first premolar with three separate roots trifurcating at midroot.
B, Radiograph of three views.
Small canals diverging from the main canal create a configuration that is very difficult to prepare and obturate
biomechanically

75. Root section of a premolar showing a ribbon-shaped canal system
Diagrammatic representation of Kartal andYanikoglu’s canal configurations

78. Mesial view of a mandibular premolar with a
Vertucci typeV canal configuration.
The lingual canal separates from the main canal
at nearly a right angle.
B,This anatomy requires widening of access in
a lingual direction to achieve straight-line
access to the lingual canal.

80. crown down instrumentation.

81. • Circular shape
• Flat shaped
• Circular & flat
• Flat ribbon shape
Concluded that maxillary first molar shows a very complicated canal
shape at the apical limit which makes cleaning & shaping followed by
obturation difficult, particularly in MB1 & distobuccal canals.

83. NI-TI

84. Controlled & directed canal preparation
into the bulky portions / safety zones,
away from the thinner portions of the
curved canals – which risk of stripping or
perforation – danger zone.

85. NI -TI

86. CHALLENGES FACED DUE TO APICAL THIRD
ANATOMY IN ENDODONTIC SURGERY

87. Leakage through dentinal tubules originating at the beveled root surface.
A, Reverse filling does not extend coronally to the height of the bevel. Arrows indicate
a possible pathway for fluid penetration.
B, Reverse filling extends coronally to the height of the bevel, blocking fluid
penetration (arrows) into the root canal space.

88. FREQUENCY OF ACCESSORY CANALS & RAMIFICATION
FOUND AT DIFFERENT LEVELS OF ROOT CANALS

90. ISTHMUS

93. Schematic representation of isthmus classifications described by Kim et al.
Type I is an incomplete isthmus - faint communication between two canals.
Type II is characterized by two canals with a definite connection between them (complete isthmus).
Type III is a very short, complete isthmus between two canals.
Type IV is a complete or incomplete isthmus between three or more canals.
TypeV is marked by two or three canal openings without visible connections.

97. Conclusion

102. THANK YOU