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1
HypodontiaSupernumerary Teeth
Lecture 4Ingrid Reed DDS, MS
Department of Orthodontics and Dentofacial Orthopedics
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Glossary
Hyperdontia Anodontia Oligodontia Hypodontia
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Hypodontia
Absence of one to five teeth Incidence Etiology If primary tooth missing – can’t have permanent tooth
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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 births04/10/23
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Hypodontia
Usually affects the last tooth in a series Lateral incisors Second premolars Third molars
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Treatment
Maintain primary tooth Replacement Extraction of primary tooth
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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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Case 1
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Profile Change
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Case 1
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Case 2
Missing 5’s and 8’s
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Profile Change
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Missing third molars
Calcification of 8’s starts at 8-14 years of age04/10/23
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Hypodontia
Missing maxillary lateral
Treatment options: Maintain space Open space Close space
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Color, size, shape& inclination of
canine
Vertical skeletal relationships
Occlusion of the buccal segments
AnteroposteriorSkeletal
relationship
Whether arches are crowded or
spaced
Patient’s attitude towards treatment
TREATMENT DECISION
MISSING MAXILLARY LATERAL INCISORS
MAINTAINOPEN SPACECLOSE SPACE
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Canine substituion
Malocclusion Class II with no
mandibular crowding Class I with
mandibular crowding – extract 2 mandibular teeth
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Canine Substitution
Diagnostic wax –up critical
Anterior tooth size excess may need to be reduced
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Canine substitution
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Profile
Balanced Relatively straight
profile Mildly convex profile
may also be acceptable
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Canine
Shape
Color
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Crown width at CEJ
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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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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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Microdontia is an expression of hypodontia
Bolton discrepancy
Build up laterals04/10/23
Supernumerary Teeth
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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
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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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12 years 8 months
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8 months later
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Treatment time 1 year 9 months
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Supernumerary
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Supernumerary teeth
Third premolar
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Supernumerary teeth
Fourth molar Also called
“distodens”
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Supernumerary TeethSupernumerary Teeth
Cleidocranial DysplasiaCleidocranial Dysplasia04/10/23
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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
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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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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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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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112233
4455
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112222
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4455
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Reading
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Contemporary Orthodontics, 4th Contemporary Orthodontics, 4th Edition Edition
William R. ProffitWilliam R. ProffitHenry W. Fields Jr.Henry W. Fields Jr.David M. SarverDavid M. Sarver
Pages 87-88, 138-139, 243, 449-453, Pages 87-88, 138-139, 243, 449-453,