990 likes | 2.75k Views
Hypodontia Supernumerary Teeth. Lecture 4 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics. Glossary. Hyperdontia Anodontia Oligodontia Hypodontia. Hypodontia. Absence of one to five teeth Incidence Etiology
E N D
HypodontiaSupernumerary Teeth Lecture 4 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics
Glossary • Hyperdontia • Anodontia • Oligodontia • Hypodontia
Hypodontia • Absence of one to five teeth • Incidence • Etiology • If primary tooth missing – can’t have permanent tooth
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
Hypodontia • Usually affects the last tooth in a series • Lateral incisors • Second premolars • Third molars
Treatment Maintain primary tooth Replacement Extraction of primary tooth
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
Case 2 Missing 5’s and 8’s
Missing third molars Calcification of 8’s starts at 8-14 years of age
Missing maxillary lateral Treatment options: Maintain space Open space Close space Hypodontia
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
Malocclusion Class II with no mandibular crowding Class I with mandibular crowding – extract 2 mandibular teeth Canine substituion
Diagnostic wax –up critical Anterior tooth size excess may need to be reduced Canine Substitution
Profile • Balanced • Relatively straight profile • Mildly convex profile may also be acceptable
Shape Color Canine
Canine substitution - ideal • Canine same color as central incisor • Narrow at the CEJ • Relatively flat labial surface • Narrow mid-crown width (buccolingually)
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
Microdontia is an expression of hypodontia Bolton discrepancy Build up laterals
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
Supernumerary teeth • Mesiodens • Often exist singularly, but sometimes in combo • Most common cause of unerupted upper central incisor • Can deflect tooth
Supernumerary teeth • Third premolar
Supernumerary teeth • Fourth molar • Also called “distodens”
Supernumerary Teeth Cleidocranial Dysplasia
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
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