1. HypodontiaSupernumerary Teeth Lecture 4 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics

2. Glossary • Hyperdontia • Anodontia • Oligodontia • Hypodontia

3. Hypodontia • Absence of one to five teeth • Incidence • Etiology • If primary tooth missing – can’t have permanent tooth

7. Hypodontia • Random – no other associations • Hypothyroidism: thyroid, pituitary, hypothalamus abnormalities • Down Syndrome: trisomy 21 • Ectodermal dysplasia: group of syndromes, missing or peg shaped teeth. Thin sparse hair Absence of sweat glands • Cleft palate : one in 600-800 births

8. Hypodontia • Usually affects the last tooth in a series • Lateral incisors • Second premolars • Third molars

9. Treatment Maintain primary tooth Replacement Extraction of primary tooth

10. No crowding retain and build-up remove & implant Mild crowding –remove after 2’s erupt to encourage space closure Severe crowding – leave and remove later Missing second premolars

11. Case 1

14. Profile Change

15. Case 1

16. Case 2 Missing 5’s and 8’s

19. Profile Change

20. Missing third molars Calcification of 8’s starts at 8-14 years of age

21. Missing maxillary lateral Treatment options: Maintain space Open space Close space Hypodontia

22. MISSING MAXILLARY LATERAL INCISORS Color, size, shape & inclination of canine Patient’s attitude towards treatment Vertical skeletal relationships TREATMENT DECISION Whether arches are crowded or spaced MAINTAIN OPEN SPACE CLOSE SPACE Anteroposterior Skeletal relationship Occlusion of the buccal segments

25. Malocclusion Class II with no mandibular crowding Class I with mandibular crowding – extract 2 mandibular teeth Canine substituion

26. Diagnostic wax –up critical Anterior tooth size excess may need to be reduced Canine Substitution

27. Canine substitution

28. Profile • Balanced • Relatively straight profile • Mildly convex profile may also be acceptable

29. Shape Color Canine

30. Crown width at CEJ

31. Canine substitution - ideal • Canine same color as central incisor • Narrow at the CEJ • Relatively flat labial surface • Narrow mid-crown width (buccolingually)

32. If the patient has an excessive gingiva to lip distance on smiling, the gingival levels will be more visible The gingival margin of the natural canine should be positioned slightly incisal to the central incisor gingival margin Lip Level

33. Microdontia is an expression of hypodontia Bolton discrepancy Build up laterals

34. Supernumerary Teeth

35. Supernumerary teeth • Maxillary midline = most common location called a mesiodens • 85% are in anterior part of maxilla • Laterals, premolars and 4th molars can also appear

36. Supernumerary teeth • Mesiodens • Often exist singularly, but sometimes in combo • Most common cause of unerupted upper central incisor • Can deflect tooth

39. 12 years 8 months

41. 8 months later

42. Treatment time 1 year 9 months

44. Supernumerary

46. Supernumerary teeth • Third premolar

47. Supernumerary teeth • Fourth molar • Also called “distodens”

48. Supernumerary Teeth Cleidocranial Dysplasia

49. Supernumerary teeth • Treatment aimed at extraction before problems arise, or minimizing effect on other teeth • General rule: more supernumeraries, more abnormal, higher their position, harder to manage

50. Remove If it erupts Inverted Displacing adjacent teeth Producing diastema Delaying eruption of permanent tooth Don’t remove If well above the apices of the permanent tooth Observe Conical supernumerary teeth