Hypodontia Supernumerary Teeth Lecture 4 Ingrid Reed DDS, MS Department of Orthodontics and Dentofacial Orthopedics 3/25/2017

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. 3/25/2017

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 dysplasia136-137, Random 3/25/2017

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) 3/25/2017

Sister Brandi 3/25/2017

3/25/2017 Brother Leonard Missing upper 2nd premolars Upper first and second molars Lower central incisors Lower 2nd premolars Lower 2nd molars 3/25/2017

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 3/25/2017

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 3/25/2017

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) 3/25/2017

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 3/25/2017

Case 1 3/25/2017

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Profile Change Scanlon, from Dolphin 3/25/2017

Case 1 3/25/2017

Case 2 Missing 5’s and 8’s 3/25/2017

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Profile Change 3/25/2017

Missing third molars Calcification of 8’s starts at 8-14 years of age 3/25/2017 Calcification of 8’s starts at 8-14 years of age

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 3/25/2017

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 3/25/2017

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Restored with composite. 3/25/2017

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 3/25/2017

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 3/25/2017

Canine substitution 3/25/2017

Profile Balanced Relatively straight profile Mildly convex profile may also be acceptable A convex profile with a retrusive chin is not a good candidate 3/25/2017

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 3/25/2017

Crown width at CEJ Pre-treatment periapical radiograph Evaluate crown width @ CEJ Helps determine emergence profile Narrow mesiodistal CEJ= more esthetic emergence profile Wide mesiodistal CEJ= poor emergence profile 3/25/2017

Canine substitution - ideal Canine same color as central incisor Narrow at the CEJ Relatively flat labial surface Narrow mid-crown width (buccolingually) 3/25/2017

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 3/25/2017

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 3/25/2017

Supernumerary Teeth 3/25/2017

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 3/25/2017

Supernumerary teeth Mesiodens Often exist singularly, but sometimes in combo Most common cause of unerupted upper central incisor Can deflect tooth 3/25/2017

The problem here is that the lateral incisor is erupting ahead of the central due to the mesiodens 3/25/2017

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12 years 8 months 3/25/2017

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8 months later 3/25/2017

Treatment time 1 year 9 months 3/25/2017

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Supernumerary 3/25/2017

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Supernumerary teeth Third premolar 3/25/2017

Supernumerary teeth Fourth molar Also called “distodens” 3/25/2017

Cleidocranial Dysplasia Supernumerary Teeth Cleidocranial Dysplasia 3/25/2017

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 450-451 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 3/25/2017

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 3/25/2017

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 3/25/2017

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 3/25/2017

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4 1 5 3 2 3/25/2017

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3 7 5 2 6 4 2 1 3/25/2017

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Reading Contemporary Orthodontics, 4th Edition William R. Proffit Henry W. Fields Jr. David M. Sarver Pages 87-88, 138-139, 243, 449-453, 3/25/2017