Anomalies 1: disorders of number, size and form Flashcards
How long after eruption of primary teeth is root formation complete?
12-18 months
How long after eruption of permanent teeth is root formation complete?
2-3 years
What are the 2 types of anomalies of tooth number?
hypodontia or supernumerary teeth
What is hypodontia?
the developmental absence of primary or permanent teeth
What is severe hypodontia (AKA oligodontia)?
the developmental absence of 6 or more teeth excluding 3rd permanent molars
What is anodontia?
the complete developmental absence of teeth
What is an example of a single gene defect causing hypodontia?
MSX1
What syndromes may hypodontia notably be a feature of?
- ectodermal dysplasia
- trisomy 21
- cleft lip and palate
- solitary median maxillary central incisor syndrome
What is an environmental aetiology of hypodontia?
sequels of severe disease and cancer treatment in early childhood
During what stage of tooth development does hypodontia occur?
initiation stage of dental development
What are the clinical features of hypodontia?
- failure of a primary tooth to exfoliate at the expected time
- a permanent tooth hasn’t erupted several months after the primary exfoliates
- teeth erupting out of sequence
- the contralateral tooth has been erupted for some time (>6 months should raise suspicion)
- other teeth appear unusually spaced
- primary may become infraoccluded
- often associated with microdontia
- associated with ectopic position of permanent teeth
- no tooth palpable in sulcus
What is infraocclusion?
primary tooth becomes ankylosed, child keeps on growing but the tooth is stuck in position so the rest of the child’s dentition and alveolus is growing normally around it
primary tooth looks ‘sunken’ or ‘submerged’
What is ectodermal dysplasia?
- a group of inherited conditions
- classic form is X-linked hypohydrotic but there are >180 identified types
What is affected by ectodermal dysplasia?
structures arising from ectoderm:
- teeth
- skin
- hair
- nails
- glands
What effects does ectodermal dysplasia have on teeth?
- very variable
- severe hypodontia, occasionally anodontia
- microdontia
- classic conical shaped teeth
What are the dental considerations in a patient with ectodermal dysplasia?
- function
- trauma
- aesthetics
- treatment fatigue
- xerostomia
- overclosure
- comfort in the dental surgery (heat)
- in some cases the dentist makes the diagnosis (subject the genetic confirmation)
What is the most well known/easily recognised type of ectodermal dysplasia?
X-linked hypohydrotic ED
What are some characteristic features of ectodermal dysplasia?
- characteristic features of sparse hair, dry skin, inability to sweat
- may also suffer form xerostomia, dry eyes and nasal congestion
- characteristic conical appearance of teeth, microdontia and hypodontia of multiple teeth
What is the role of the GDP in the management of hypodontia?
- early detection
- prevention of caries, perio
- referral
What is the role of the multidisciplinary team in the management of hypodontia?
- confirmation of diagnosis
- coordination of care - paeds, restorative, ortho, GDP
- redistribution of space
finish from PPT
What are supernumerary teeth?
the presence of a tooth/teeth in addition to the normal sequence
At what stage of development do supernumerary teeth occur?
initiation stage of tooth formation
What is the aetiology of supernumerary teeth?
- genetic, often runs in families
- a feature of some syndromes
What syndromes may supernumerary teeth be a feature of?
- cleidocranial dysplasia
- cleft lip and palate
- gardner syndrome
What can supernumerary teeth be defined by?
position and/or shape
What positions can supernumerary teeth be defined by?
mesiodens, paramolar
What shapes can supernumerary teeth be defined by?
- conical
- tuberculate
- supplemental
- odontome
What are the features of conical supernumerary teeth?
- most common (~75%)
- likely to erupt if not inverted, but not always
- often but not always impede eruption of other teeth
- often occurs in midline maxilla
- often in pairs
- often inverted
What are the features of tuberculate supernumerary teeth?
- ~12%
- barrel shaped
- do not usually erupt
- very likely to impede eruption of other teeth
- often occur in pairs
What are the features of supplemental supernumerary teeth?
- ~7%
- has normal anatomy
- often a supplemental lateral incisor, 3rd premolar or 4th molar
- likely to erupt, particularly supplemental incisors
- less likely than other types to impede eruption
What are the features of odontome supernumerary teeth?
- ~6%
- collection of tooth tissue
- compound: denticules
- complex: disorganised collection of tooth tissue
- will not erupt
- very likely to impede eruption of nearby teeth
What are the clinical features of supernumerary teeth?
- first sign by be eruption of supernumerary or delayed eruption of normal sequence
- may cause crowding, rotation, malposition, ectopic positon of surrounding teeth
- frequently in anterior maxilla, common cause of delayed eruption of central incisor
- clinical examination should include palpation for the presence and positon of unerupted teeth
What is involved in the management of supernumerary teeth?
- monitor
- simple extraction
- surgical extraction
- teeth which have been impeded may need to be surgically exposed +/- orthodontically repositioned
What is cleidocranial dystosis?
rare autosomal dominant condition
What are the characteristics or cleidocranial dystosis?
- hypoplastic or absent clavicles, short stature, characteristics facial features
- dental features include multiple supernumerary teeth, delayed/failures exfoliation of primary teeth and delayed/failed eruption of permanent teeth
What is the management of cleidocranial dystosis?
- multiple, complex surgeries required and orthodontic treatment
- treatment occurs in multiple stages and lasts many years
Is it always necessary to extract supernumerary teeth?
no, may not always cause problems
What is microdontia?
smaller the average tooth/teeth
During what stage of development does microdontia occur?
morphogenesis stage of tooth formation
What is the aetiology of microdontia?
- genetic component
- environmental e.g. childhood illness, cancer treatment
- associated with hypodontia
- associated with syndromes:
- ectodermal dysplasia
- cleft lip and palate
What tooth us most commonly affected by microdontia?
maxillary lateral incisor - peg lateral
What is peg lateral often assocated with?
contralateral hypodontia in 40% of cases
What are the clinical features of microdontia?
- generalised microdontia presents with spacing
- localised microdontia is usually later incisor - small, often narrow and conical or “peg shaped”
- microdont laterals are associated with increased incidence of palatally ectopic canines
What are peg laterals often associated with?
microdont laterals are associated with increased incidence of palatally ectopic canines
What are management options for microdontia?
- accept
- orthodontic space redistribution
- composite build up
- extract
What is macrodontia?
larger than average tooth/teeth
What is the aetiology of macrodontia?
usually the tooth is large because it is a double tooth, or has a defect such as talon cusp
What are the different types of double teeth?
- fusion: two teeth germs joined together, there may be associated hypodontia
- gemination: one tooth germ incompletely divided
- extent of separation of crown and root is very variable
What may macrodontia be associated with?
supernumeraries
What are the clinical features of macrodontia?
- large crown
- crown may have features such as extra cusps of grooves
- likely to be crowding
What are the radiographic features of macrodontia?
- root form and root canal anatomy varies and depends of reason for macrodontia
- double teeth vary from two separate roots to butterfly-shaped with two canals or one canal to a single large root
What are the management options for macrodontia?
- accept
- reshape
- extract
What teeth are relatively commonly fused in the primary dentition?
lateral incisor and canine
What is dens invaginatus?
- AKA dens in dente or “tooth within a tooth”
- the enamel is folded in on itself creating an enamel lined cavity within the tooth
What are the classifications of dens invaginatus?
Oehler’s classification:
- Type I
- Type II
- Type III A
- Type III B
What is Type I dens invaginatus?
invagination is limited to the crown up to amelocemental junction
What is Type II dens invaginatus?
Invagination extends into the root beyond the cementoenamel junction with no communication with the dental pulp
What is Type III A dens invaginatus?
Invagination extends into the root and communicates laterally through a pseudoforamen with the PDL with no pulpal communication
What is Type III B dens invaginatus?
Invagination extends into the root and communicates apically through a pseudoforamen with the PDL with no pulpal commutation
At what stage of development does dens invaginatus occur?
morphogenesis stage of tooth development
What is the aetiology of dens invaginatus?
possible genetic component
What teeth does dens invaginatus most commonly affect?
maxillary lateral incisors, then maxillary central incisors
What are the clinical features of dens invaginatus?
- often subtle
- pronounces cingulum pit
- first indications may be unexplained loss of vitality in the absence of trauma or caries
What are the radiographic features of dens invaginatus?
- the infold of enamel will be visible on a periapical radiograph
- can appear to have additional root canal(s)
- root may be expanded
- often has apical radiolucency as a result of loss of vitality
-CBCT may be indicated if RCT is to be attempted to assess root and canal morphology
What are the management options for dens invaginatus?
- identification and fissure sealant of deep cingulum pits
- when loss of vitality occurs RCT can be attempted, this can be high complexity and referral to paediatric dentist/endodontist is usually required
- extract if root morphology is too complex
What is dens evaginatus?
an additional cusp or tubercle AKA talon cusp
At what stage of development does dens evaginatus occur?
morphogenesis stage of tooth development
What is the aetiology of dens evaginatus?
genetic component - different prevalence in different populations
What are the teeth commonly affected by dens evaginatus?
- lower second premolars commonly affected in Asian populations
- talon cusps common on maxillary incisors
What are the clinical features of dens evaginatus?
- May be clinically obvious or may have already worn down due to attrition (particularly premolars)
- On premolars usuallv presents as a central cusp, if already worn down may present as an area of exposed dentine in the centre of the tooth
- Premolars may lose vitality without any obvious reason such as a carious lesion
- On incisors a talon cusp is usually on the palatal aspect
- It may intertere with the occlusion, lead to displacement or the root or prevent orthodontic treatment
- Where tnere is a large additonal cusp it can be difficult to differentiate from a supernumerary tooth in close association with the affected incisor
- Often bilateral
What are the radiographic features of dens evaginatus?
- diagnoses clinically
- radiograph may show a pulp extension into the extra cusp
- root morphology is usually normal
What are the management options for dens evaginatus?
- accept and prevention: OHI and fissure seal
- the additional cusp will usually contain a pulp horn
- gradual reduction - multiple appointments to grind the cusp down and encourage laying down of reactionary dentine to prevent pulp exposure
- removal of the cusp and pulp capping/pulpotomy/RCT
What is dilaceration?
a bend in the root or crown of the tooth
What is the aetiology of dilaceration?
- usualy an acquired defect affecting a permanent tooth, often resulting from trauma to the primary tooth
- the highest risk injuries are avulsion or intrusion of the primary teeth
- rarely caused by pathology such as cysts interfering with the path of crown-root formation
- the positon of the dilaceration along the long axis of the tooth depends on the stage of tooth development at time of the insult (refer to the tooth development atlas)
What teeth are most commonly affected by dilaceration?
maxillary central incisors
What are the clinical features of dilaceration?
- frequently failure of eruption
- occasionally altered path of eruption
- ectopic position
- a dilaceration in the crown will be visible in an erupted tooth
What are the radiographic features of dilaceration?
- can be difficult to assess on plain films
- a lateral ceph can show a dilacerated incisor
- to properly assess the tooth morphology a CBCT is useful
What are the management options for a dilacerated tooth?
- a mildly dilacerated tooth can often be orthodontically aligned
- a severe root dilaceration may not be able to be aligned if aligning the crown means the root apex would perforate the cortical plate
- if unerupted the surgical exposure and bonding or surgical extraction may be required
- mild dilacérations confined to the crown can be disguised with composite/selective shaping of the enamel
What is taurodontism?
elongated pulp chamber in a multi-rooted tooth resulting in differences in root morphology with a low bifurcation
What are the classifications of taurodontism?
can be classified by pulp chamber:root canal ratio (Shaw classification)
During what stage of development does taurodontism occur?
morphogenesis phase of tooth development
What may taurodontism be associated with?
some types of amelogenins imperfecta, and can present in some syndromes such as trisomy 21 and klinefelter
What are the clinical and radiographic features of taurodontism?
- clinically visible crown appears normal
- radiographically usually an incidental finding, long pulp chamber with short root canals
What is involvement in management of taurodontism?
- no management needed unless the tooth requires treatment for another reason
- it may be more difficult to perform RCT due to internal morphology
- extraction can be more challenging
What are the possible aetiologies of short roots?
genetic or environmental/acquired
What are possible environmental/acquired causes of short roots?
- arrested root development as a result of loss of vitality prior to apexogensis
- arrested root development as a result of illness or treatment e.g. childhood cancer during root formation
- root resorption caused by intrinsic factors e.g. traumatised tooth or extrinsic factors e.g. ortho, ectopic teeth, pathology
What are the clinical features of short rooted teeth?
- may be no clinical signs
- where roots are very short there may be mobility
- where the cause is loss of vitality there may be symptoms of pain or signs such as sinus, negative sensibility etc
- where the cause is childhood illness there mat be other associated anomalies such as microdontia and enamel defects
What are the radiographic features of short rooted teeth?
- where there is arrested development due to loss of vitality the dentine walls will be thin and root canal wide
- where there is arrested development without loss of vitality the roots may be tapered to a point
- where there has been resorption of previously fully formed teeth the dentine walls and the root canal will be normal width and the apex blunted, there may be other irregularity in the outline of the root
What are the management options for short rooted teeth?
- depends on cause
- non-vital teeth need root canal treatment with apexification
- vital teeth do not need active intervention but care must be taken with orthodontic treatment, trauma should be avoided by use of a mouthguard for sports (anterior teeth) and periodontal health well maintained
- where roots are very short plans must be made for their eventual loss
infraocclusion
What anomaly is shown here?
hypodontia
What anomaly is shown here?
hypodontia
What anomaly is shown here?
Supernumerary (supplemental - central incisor)
What anomaly is shown here?
supernumerary (odonotomes)
What radiograph view can be used to locate supernumerary teeth?
DPT to identify, parallax to locate in relation to other teeth
What anomaly is shown here?
microdontia - peg lateral
What anomaly is shown here?
macrodontia
What anomaly is shown here?
dens invaginatus
What anomaly is shown here?
dens evaginatus
What anomaly is shown here?
dens evaginatus
What anomaly is shown here?
dilaceration
What anomaly is shown here?
taurodontism
