1. Chapter 8: Application of Root and Pulp Morphology Related to Endodontic Therapy

2. I. Internal Pulp Cavity Morphology Related to Endodontic and Restorative Therapy

3. A. Shape of Pulp Cavities and Configuration of Pulp Canals
Pulp Chamber and Pulp Horns
Root Canals (Pulp Canals)

4. 1. Pulp Chamber and Pulp Horns, Canals, Foramen, and Orifices (on Chamber Floor)

5. 2. Root Canals (Pulp Canals)
Type I: One canal to one foramina
Type II: Two separate canals join at one apical foramina
Type III: Two separate canals from chamber continue to two separate apical foramina
Type IV: One canal from chamber but splits to two canals and apical foramina

6. Root Canals (Types)

7. Root Canals (Pulp Canals): Accessory Canals
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8. Root Chamber and Canal Shapes (on Sectioned Teeth)

9. B. Shape of Pulp Cavities in Sound Young Teeth
Pulp Shape in Anterior Teeth
Pulp Shape in Premolars
Pulp Shape in Molars
Pulp Shape in Primary Teeth

10. 1. Pulp Shape in Anterior Teeth (Incisors and Canines)
Pulp Chamber and Pulp Horns
Root canal(s)

11. a. Pulp Horns of Anterior Teeth
Incisors often have three pulp horns: mesial, central, and distal correlating with three facial lobes and three mamelons (on incisors)
Peg lateral incisors (forming from one lobe) are more likely to have only one pulp horn
Canines have one pulp horn under the one cusp

12. Pulp Chamber and Pulp Horns of Two Incisors (Only Two Horns Visible)

13. Pulp Chamber and Pulp Horns of Young Tooth; Chamber Extends Well Into Crown

14. Pulp Chamber and Horns of Two Young Canines; Larger Chamber Extends Well Into Each Crown

15. b. Root Canals of Anterior Teeth
Most likely one root with one canal
If two canals exist, most likely one is facial and one is lingual

16. 2. Pulp Shape in Premolars
Pulp Chambers in Premolars
Root Canal(s) of Premolars

17. a. Pulp Chamber and Horns in Premolars
Normally one pulp horn per functional cusp; therefore, most have two horns
Mandibular first premolars with functionless lingual cusp may have only one pulp horn (as in canines)
Mandibular second premolars with three cusps have three pulp horns

18. b. Root Canal(s) and Orifices in Premolars
All premolars EXCEPT maxillary firsts most often have one root with one canal
Maxillary second premolars most often have two roots with one canal in each root. Even with one root, these teeth most likely have two canals (one buccal and one lingual). On this tooth, there are two orifices in the chamber floor.

19. Pulp Chamber and Horns in Premolars: Mandibular Premolar on Radiograph (as though sectioned mesiodistally)

20. Pulp Chamber and Horns in Premolars: Mandibular First Premolar sectioned Faciolingually showing the usual One Root and One Canal

21. Pulp Chamber and Horns in Premolars: Mandibular First Premolar sectioned Faciolingually showing a Split Root with Two Canals Apically

22. Pulp Chamber and Horns in Premolars: Maxillary First Premolar on Radiograph showing Two Filled Canals

23. Pulp Chamber and Horns in Premolars: Maxillary First Premolar Sectioned Faciolingually showing Two Roots (Buccal and Lingual), Two Canals, and Two Horns: (Buccal and Lingual)

24. Root Chamber Orifices Visible Through Access Openings

25. 3. Pulp Shape in Molars Pulp Chamber and Pulp Horns
Root Canals and Orifices

26. a. Pulp Chamber and Horns of Molars (Young Maxillary Molar With Larger Chamber and Horns Well Into Crown)

27. Pulp Chamber and Horns of Molar (Older Mandibular Molar: Smaller Chamber in Root Trunk, Only Horns Into Crown)

28. b. Root Canal(s) and Orifices of Molars
Maxillary molars most often have three roots and four canals (two in mesiobuccal root), and four orifices in the chamber floor
Mandibular molars most often have two roots but three canals (two in mesial) and three orifices in the chamber floor

29. Root Chamber Orifices (Maxillary Molar with Four Orifices)

30. Root Chamber Orifices of Molars

31. 4. Pulp Shape in Primary Teeth (Compare the Primary to Secondary Molars)
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Similar to adult dentition except pulp is proportionately larger than on secondary teeth (with thinner enamel and dentin) so pulp is closer to the external surface

32. C. Why Pulp Cavities Get Smaller in Older Teeth
Deposit of secondary (additional) dentin as we age
New dentin (reparative) forms as reaction to injury
Calcium hydroxide base can be used to stimulate additional dentin

33. D. Clinical Application of Pulp Morphology Related to Restorative Dentistry
Know shape to avoid exposing pulp when preparing teeth for restorations
Avoid damage to pulp with burs/heat/air
Determine need for dental bases to protect, insulate, etc.
Knowledge of morphology critical when removing pulp (endodontic therapy)

34. E. Clinical Application of Pulp Morphology Related to Endodontics

35. 1. Endodontics Defined
Is a specialty concerned with human dental pulp and periapical tissues
Periradicular (around the root) conditions
Endodontist: is the specialist in endodontics

36. 2. Diagnosis of Pulpal and Periapical Disease
Irreversible pulpitis (pulp inflamed and cannot heal)
Periapical disease
Periapical radiolucency (dark area on x-ray around apex indicating bone loss)
Granuloma (from chronic inflammation)
Pulp death (necrosis); pulp is devital but tooth still functions

37. Diagnosis of Pulpal and Periapical Disease (Often Caused From Decay Into Pulp Seen as Dark Area on This X-ray of Molar Crown)
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38. Diagnosis of Periapical Disease Seen as Radiolucency (Dark Area of Bone Loss) Around Root Apex
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39. Diagnosis of Pulpal Disease (Crown Discoloration from Pulp Damage may be Treated with Bleaching)

40. 3. Endodontic Therapy
Develop access opening (cut a hole through roof of pulp chamber)
Locate canal orifices (on floor of chamber)
Clean out each canal (remove pulpal tissue)
Fill cleaned canals (with gutta percha)

41. Endodontic Therapy: Clean Out Canal with Files
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42. Endodontic Therapy: Fill Canals (with Gutta Percha); Temporize
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43. Endodontic Therapy: May Require Restoration With Post and Core, and Crown

44. II: Location of Root and Cervical Crown Concavities, Furcations, Depressions, and Canals (for Each Secondary Tooth Type)

45. Maxillary Central Incisors
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Cervical root and chamber outline is triangular
Cingulum to distal
No prominent root depressions (mesial is flatter)
One root canal

46. Maxillary Lateral Incisors
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Cervical root and chamber outline is egg shaped
Shallow depression on mesial of root, not distal
One root canal

47. Mandibular Central and Lateral Incisors
Cervical outline is ovoid: much wider faciolingually than mesiodistally (“ribbon-like”)
Root depression on mesial and distal; distal is deeper
One canal most common
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48. Maxillary Canines Cervical outline is ovoid and wide faciolingually
Root depression on mesial and distal; distal is deeper
One canal
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49. Mandibular Canines Cervical outline is wider faciolingually
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Cervical outline is wider faciolingually
Root depression on mesial and distal; distal is deeper
One canal most often
May have two roots and two canals (one facial and one lingual)

50. Maxillary First Premolars
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Most have two roots and two canals
Root depression mesial and distal with mesial deeper
Mesial crown cavitation at cervical
Furcation located in apical half

51. Maxillary Second Premolars
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Cervical outline at cervical is ovoid, wider buccolingually
Normally one root and one canal
Root depressions on mesial and distal (distal deeper)

52. Mandibular First Premolars
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Cervical outline is ovoid, wider buccolingually
Root depressions mesial and distal; deeper on distal
One canal most often

53. Mandibular Second Premolars
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Cervical outline is ovoid, wider buccolingually than mesiodistally
Root depression not common on mesial; frequent on distal
One canal most often
Crown outline of three-cusp type wider in lingual half

54. Mandibular First and Second Molars
Two roots (mesial and distal)
Mesial root is wider faciolingually
Three canals (two in mesial root)
Mesial root with mesial and distal root depressions
Furcation access is located midfacial and midlingual
Root trunk shorter and roots more spread on first molars than seconds, thirds
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55. Maxillary First and Second Molars
Three roots (mesiobuccal, distobuccal, and lingual)
Four canals (two in mesiobuccal)
Mesiobuccal root is wider than distobuccal
Mesiobuccal root has mesial and distal depression
Lingual root has slight lingual depression
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56. Maxillary First and Second Molars [cont.]
Furcation access is located midfacial, mesial, and distal
Maxillary first molar often has distal cervical depression
First molars have shorter root trunk and more spread roots than seconds, thirds
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