1. Dental Nomenclature II
RSD 811

2. Embrasure spaces

3. Embrasures
Negative space that surrounds each contact area when teeth are in contact with each other
Serve to direct food away from the gingiva
Restorations with improperly formed embrasures create food traps
Named for their location
Incisal/Occlusal
Facial (Labial/Buccal)
Lingual
Cervical (Interproximal Space)

4. Embrasures Very helpful when waxing teeth to proper form
An area that is over- or under-contoured in wax will affect the size and shape of the embrasure space in the finished restoration
Lingual embrasures are larger than facial embrasures
When viewed from the occlusal, teeth taper lingually to fit into the arch
Cervical embrasures are larger than incisal/occlusal

5. Embrasures
Cervical embrasures are filled with interdental papillae in a healthy mouth

6. Line angles

7. Line Angles
An arbitrary line formed by the junction of two tooth surfaces (planes)
Named for their location

8. Line Angles

9. Line Angles

10. Point Angles Formed by the junction of three tooth surfaces
Named for their location

11. Point Angles

12. Point Angles

13. Revisiting
Tooth tissues

14. Tooth Tissues
Enamel
Hard, acellular (95% calcium hydroxyapatite, 5% water)
Formed by ameloblasts
Covers the anatomical crown
Complete prior to tooth eruption
Functions to protect the dentin

15. Tooth Tissues Enamel Dentin Pulp Cementum Gingiva
Alveolus / Alveolar bone
Root canal
Cementum

16. Tooth Tissues Dentin Softer than enamel or cementum
Forms the major bulk of the tooth
Surrounds and protects the pulp cavity
Provides general form and elastic strength to the tooth

17. Tooth Tissues Dentin Formed by odontoblast cells throughout life
Primary dentin is formed prior to root completion
Secondary dentin formed following root completion

18. Tooth Tissues Dentin Enamel Pulp Cementum Gingiva
Alveolus / Alveolar bone
Root canal
Cementum

19. Tooth Tissues Cementum Similar to bone
Formed throughout life by cementoblasts
Covers the anatomical root
Attaches to the periodontal ligament

20. Tooth Tissues Dental Pulp
Connective, lymphatic, nervous and vascular tissue located in the pulp cavity and root canal spaces
Supplies nutrition to the tooth
Houses the odontoblasts (form 1° and 2° dentin)
Responds defensively to injury
Provides sensory feedback

21. Supporting structures
The Periodontium
Supporting structures

22. The Periodontium Gingiva Periodontal Ligament Alveolar Bone Enamel
Dentin
Dental Pulp
Gingiva
Cementum
Periodontal Ligament
Alveolar Bone

23. The Periodontium Surrounds the root of a tooth
The Periodontal Ligament (PDL)
Surrounds the root of a tooth
Forms an elastic attachment of the cementum to the alveolar bone
Serves sensory (proprioceptive), nutrient and formative functions

24. The Periodontium Alveolar bone
Forms alveoli and crypts of developing teeth and sockets of erupted teeth
Between the roots of adjacent teeth is termed interdental septum
Continuous with cortical layer of bone (called lamina dura)

25. The Periodontium Gingiva Covers the alveolar bone
Only tissue of the periodontium that is visible in a healthy mouth

26. The Periodontium Gingiva Attached Gingiva
Directly adjacent to alveolar bone
Physically bound to tooth or bone
Firm, pink, relatively thick keratinized tissue
Resistant to infection and trauma

27. The Periodontium Gingiva Free Gingiva Coronal to the alveolar bone
Not bound to the tooth
Creates gingival sulcus

28. The Periodontium Gingiva Free Gingiva
Papillary Gingiva/Interdental Papillae
Free gingiva that occupies the interdental space
Located below the contact area

29. The Periodontium Gingiva Free Gingiva Marginal Gingiva
Free gingiva located facial and lingual to each tooth
Joins the papillary gingiva located interproximally

30. The Periodontium Alveolar Mucosa Differs in: Mucogingival junction
The soft tissue covering located apical to the attached gingiva
Mucogingival junction
Differs in:
Color
Thickness
Structure
Attachment

31. The Periodontium
Alveolar Mucosa

32. Eruption process and sequence
Tooth development

33. General Information Much of tooth development occurs prior to eruption
First primary tooth erupts at 6 months
First permanent tooth erupts at 6 years
Mandibular teeth typically erupt before maxillary teeth
Sequence is usually the same, though actual eruption times vary

34. Calcification
Tooth tissues become hardened by deposit of mineral salts in enamel, dentin, bone and cementum
Primary teeth begin to calcify at 4 months in utero
Complete at 3-4 years
Permanent teeth begin calcification soon after birth
Complete at years

35. Calcification

36. Lobe Formation
Tooth formation begins with the crown and continues apically
Initiates in 4-5 growth centers (Lobes)
Lobes coalesce into crown, then root formation follows
Form, contour and arrangement of the lobes determines tooth form

37. Lobe Formation
All anterior teeth and most posterior teeth develop from 4 lobes
Anterior teeth and premolars:
3 facial lobes
1-2 lingual lobes
Molars:
2 facial lobes
2-3 lingual lobes

38. Lobe Formation 1 2 3 5 5 4 Mandibular first molar
Maxillary first molar
(with Cusp of Carabelli)
Mandibular second premolar
(in some cases)

39. Lobe Formation Anterior Teeth
Mammelon – a rounded protuberance found on the incisal ridges of newly erupted incisors
Suggest the location of the three facial lobes
Mesiofacial
Central facial
Distofacial
Wear away over time

40. Lobe Formation Anterior Teeth
Cingulum – a lingual lobe of an anterior tooth making up most of the cervical 1/3 of the lingual surface

41. Eruption
The penetration of oral mucosa as a tooth enters the oral cavity
At the time of eruption, the crown is fully developed (calcification is complete) while the root is approximately 2/3 complete
The eruption process is aided by:
Development of the root which forces further eruption
Bone growth at the base of the alveolus

42. Eruption Sequence: Primary Dentition
Centrals: 6 months-1 year
Laterals: 9 months-16 months
1st Molars: years
Canines: years
2nd Molars: 2-3 years

43. Eruption Sequence: Permanent Dentition
Mand 1st Molar: 6 years
Mand Centrals: 6 years
Mand Laterals: 7 years
Mand Canine: 10 years
Mand 1st PM: 10 years
Mand 2nd PM: 11 years
Mand 2nd Molars: 12 years
Mand 3rd Molars: 20 years
Max 1st Molar: 6 years
Max Centrals: 7 years
Max Laterals: 8 years
Max 1st PM: 10 years
Max 2nd PM: 11 years
Max Canine: 11 years
Max 2nd Molars: 12 years
Max 3rd Molars: 20 years

44. Eruption Sequence: Permanent Dentition

46. Primary Root Resorption
Allows development and eruption of the permanent teeth
Results from pressure atrophy from the crowns of succedaneous teeth

47. Primary Root Resorption
Nonsuccedaneous teeth do not replace existing primary teeth
Permanent molars

48. Extrusion Active eruption due to loss of the antagonist
When a tooth erupts into contact with its antagonist, further active eruption is halted. It may continue later due to occlusal wear or loss of an opposing tooth

49. Active Eruption
The process of actual bodily movement of the tooth relative to the tissues of the jaw
Attrition – the wearing away of the functioning surfaces of teeth due to use

50. Passive Eruption
Recession of the periodontium resulting in a longer clinical crown

51. Summary: Life of a Tooth
Development from lobes
Lobes coalesce
Root formation
Active eruption and continued root formation
Attrition
Active Eruption
Passive Eruption