Oral Med Developmental Abnormalities

- congenital absence of one or more teeth, most commonly the third molars, maxillary laterals, or mandibular 2nd premolars

- this is hypodontia associated with a genetic disorder where there are problems arising from ectodermal problems
- There are problems with things that develop from the ectodermal layer (glandular tissue, salivary glands, sebasceous glands, hair follicle, dental structures)
- hair is space and thin, anhydrotic means that the patient does not produce sweat = temp regulation problems

- 90% in the maxilla, can be single or multiple excess teeth
- mesiodens is the most common (between the maxillary centrals)
- 4th molars, lateral incisors are also common
cleidocranial dysplasia will result in pseudohypodontia with hyperdontia because the teeth will be present but not erupted

- can be true generalized, generalized relative, or microdontia involving a single tooth
- can be a problem because these teeth will generate diastemas in the dentition

- can be true generalized, relative generalized, macrodontia involving a single tooth, or from facial hemi-hypertrophy
- note that the macrodontia also occurs in the apical portion of the tooth in addition to the crown

- an abnormally shaped crown tht is extra wide due to the development of two crowns from one tooth germ
- opposite of fusion (single tooth that attempts to develop from two germs)

- abnormally shaped tooth that may appear as an extra wide crown, a normal crown with an excess root, etc resulting from the union of two adjacent tooth germs by dentin during development

- developmental anomaly in which the focal area of the crown of a maxillary lateral is folded inward
- when severe this results in a conically shaped tooth with a small surface opening that is quickly subject to caries, pulpitis, and PA inflammation
- looks like a radiodensity within another tooth

- A developmental anomaly in which a focal area of the crown projects outwards and produces what appears to be an extra cusp or abnormal shape to the existing cuspal arrangement (talon cusp)
- instead of the lamina going inwards, it goes out

- a sharp bend or angulation in the root portion (occasionally the crown, but normally the root)
- can be from trauma, continued formation during a curve of eruption, idiopathic
- complicates extractions

- a molar with an elongated crown and apically placed furcation of the roots, resulting in an enlarged rectangular coronal pulp chamber
- developmental associated with amelogenesis imperfecta, Down's Syndrome, common in the Neandrethal man
- no treatment needed, results in a complicated RCT

- two or more roots unite by cementum, but this occurs after root formation (unlike fusion)
- caused by trauma, crowding and is more common in the maxillary molars

- located at the CEJ 1-3mm long and 1mm wide
- contributes to periodontal pocketing due to its rounded spherical nature contributing to plaque accumulation

- Excessive deposit of cementum on the root surface
- caused by increased or decreased forces, Paget's disease, hyperpituitarism, chronic infection
- no treatment needed, need to identify for clinical purposes

- extra roots, more than the expected number
- more common in the mandibular bicuspids