1. Hypodontia Supernumerary Teeth
Lecture 4
Ingrid Reed DDS, MS
Department of Orthodontics and Dentofacial Orthopedics
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2. Glossary Hyperdontia Anodontia Oligodontia Hypodontia
Hyperdontia - extra teeth (supernumerary teeth)
Anodontia - failure of teeth to develop (agenesis of teeth) very rare
Oligodontia – 6 or more missing teeth – rare
Hypodontia – less than 6 congenitally missing teeth
Page 135
Congenital absence of teeth results from disturbances during the initial stages of tooth formation – INITIATION AND PROLIFERATION.
Since primary tooth buds give rise to permanent tooth buds, if a primary tooth is missing there can’t be a successor.
Can have missing permanent teeth even when primary was present.
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3. Hypodontia Absence of one to five teeth Incidence Etiology
If primary tooth missing – can’t have permanent tooth
Incidence
3.5 – 6.5 % of population (excluding third molars)
third molars missing in 20% to 25%
Congenitally missing primary teeth – 0.1% to 0.4%
Hypodontia 1.37 times higher in girls
Commonly runs in families
Etiology – missing teeth can be inherited as part of a syndrome or isolated in an autosomal-dominant or autosomal –recessive way
Genes –MSX1, PAX9, AXIN2
Cytotoxic drugs
Radiotherapy
Syndromes – ectodermal dysplasia ,
Random
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4. The following pano’s are from a family where 2 of the 3 children had oligodontia
Here we see the youngest child with no missing teeth (Jesse)
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5. Sister Brandi
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6. 3/25/2017 Brother Leonard Missing upper 2nd premolars
Upper first and second molars
Lower central incisors
Lower 2nd premolars
Lower 2nd molars
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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 births
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8. Hypodontia Usually affects the last tooth in a series Lateral incisors
Second premolars
Third molars
The most commonly missing permanent teeth are the second premolars (more than 40% of all missing teeth) and maxillary laterals
Mandibular 2nd premolars missing more often than maxillary.
Followed by upper second molars
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9. Treatment Maintain primary tooth Replacement
Extraction of primary tooth
Maintain tooth or teeth, will have occlusal problems since second deciduous tooth is not same size as 2nd premolar
Replacement
Prosthetically
transplantation
Implant – retain 1° tooth till close to time of implant for bone
Extraction of the primary tooth and allowing permanent teeth to drift
Extraction followed by orthodontic treatment
Need to access:
facial profile
Incisor position
Space requirements
Status of the primary teeth
Specific treatment will be discussed in a later lecture (chapter 12)
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10. Missing second premolars
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
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11. Case 1
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14. Profile Change
Scanlon, from Dolphin
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15. Case 1
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16. Case 2
Missing 5’s and 8’s
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19. Profile Change
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20. Missing third molars Calcification of 8’s starts at 8-14 years of age
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Calcification of 8’s starts at 8-14 years of age

21. Hypodontia Missing maxillary lateral Treatment options: Maintain space
Open space
Close space
Open, maintain or close the space
(Implant, restoration or canine substitution)
Patient’s attitude and desire
Color, size, shape, inclination of canine
Vertical skeletal relationship
Occlusion of the buccal segment
Anteroposterior skeletal relationship
Whether arches are spaced or crowded
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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
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24. Restored with composite.
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25. Canine substituion Malocclusion Class II with no mandibular crowding
Class I with mandibular crowding – extract 2 mandibular teeth
There are two malocclusions that permit canine substitution:
Class II with no mandibular crowding
Class I with Mandibular crowding requiring extraction of two teeth
In order to finish as a Class II you need two less teeth in maxillary arch, usually premolars but can be laterals
To finish as Class I need same number of teeth in each arch
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26. Canine Substitution Diagnostic wax –up critical
Anterior tooth size excess may need to be reduced
The canine is a wider tooth so may need to reduce to establish normal overbite and overjet
Diagnostic Wax-up is critical
Evaluate
Final occlusion
Amount of reduction
Acceptable esthetics
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27. Canine substitution
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28. Profile Balanced Relatively straight profile
Mildly convex profile may also be acceptable
A convex profile with a retrusive chin is not a good candidate
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29. Canine Shape Color Canine wider with a more convex labial surface
Significant amt of reduction may be needed for acceptable esthetics – dentin may show through
Color – usually more saturated, darker
Mesioincisal and distoincisal edges may need to be restored
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30. Crown width at CEJ Pre-treatment periapical radiograph
Evaluate crown CEJ
Helps determine emergence profile
Narrow mesiodistal CEJ= more esthetic emergence profile
Wide mesiodistal CEJ= poor emergence profile
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31. Canine substitution - ideal
Canine same color as central incisor
Narrow at the CEJ
Relatively flat labial surface
Narrow mid-crown width (buccolingually)
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32. Lip Level
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
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33. Microdontia is an expression of hypodontia
Page 138
Abnormalities in tooth size and shape result from disturbances during the morphodifferentiation stage of development .
The most common abnormality is variation in size, particularly of maxillary lateral incisors and second premolars.
About 5% of the total population has a significant “tooth size discrepancy” because of disproportionate sizes of the upper and lower teeth. Discovered by BOLTON ANALYSIS
IMPORTANT CONCEPT:
UNLESS THE TEETH ARE MATCHED FOR SIZE, NORMAL OCCLUSION IS IMPOSSIBLE.
A difference of 1.5 mm or less is usually not of consequence.
Bolton discrepancy
Build up laterals
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34. Supernumerary Teeth
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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
Page 138
Supernumerary teeth result from disturbances during the initiation and proliferation stages of dental development
The presence of an extra tooth obviously has great potential to disrupt normal occlusion
Early intervention to remove them is indicated.
Mosby’s orthodontic review page 21
Incidence of hyperdontia much lower than hypodontia
Hyperdontia in primary dentition is about 0.5%
Hyperdontia in permanent dentition is about 1.0%
85% of supernumerary teeth are located in upper jaw, particularly in the premaxilla
Supernumerary tooth can be typical or atypical in shape
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36. Supernumerary teeth Mesiodens
Often exist singularly, but sometimes in combo
Most common cause of unerupted upper central incisor
Can deflect tooth
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37. The problem here is that the lateral incisor is erupting ahead of the central due to the mesiodens
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39. 12 years 8 months
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41. 8 months later
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42. Treatment time 1 year 9 months
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44. Supernumerary
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46. Supernumerary teeth
Third premolar
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47. Supernumerary teeth
Fourth molar
Also called “distodens”
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48. Cleidocranial Dysplasia
Supernumerary Teeth
Cleidocranial Dysplasia
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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
Pages
Most common area anterior maxilla
Usually discovered at age 6 or 7
Usually affect eruption of permanent teeth
Extract as soon as can remove without harming developing normal teeth
Surgery – consider access & root development of permanent tooth
Consider child’s ability to tolerate surgery
Earlier the extraction more likely permanent tooth will erupt without intervention
Later the extractions more likely need for surgical exposure of permanent tooth & ortho. Usually root has finished forming and tooth won’t erupt
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50. Conical supernumerary teeth
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
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51. Tubercle supernumerary teeth
Unlikely to erupt – remove supernumerary and retained deciduous tooth in the area
Prepare for orthodontic eruption if permanent tooth doesn’t erupt on its own
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52. Supplemental teeth
Resembles a normal tooth in morphology & commonly produces crowding or displacement
Extract the tooth most dissimilar to the contralateral tooth, unless it is severely displaced
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54. 4 1 5 3 2
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56. 3 7 5 2 6 4 2 1
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64. Reading Contemporary Orthodontics, 4th Edition William R. Proffit
Henry W. Fields Jr.
David M. Sarver
Pages 87-88, , 243, ,
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