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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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77

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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,