Dr Jamal Naim PhD in Orthodontics Dental Anomalies

Introduction Dental anomalies are disturbances in tooth development determined by: Genetic factors (inherited) and/or Environmental factors (acquired). Number, size, shape alterations as well as defects of mineralized tissues and eruptional problems are the most common dental anomalies reported.

Introduction These few facts about tooth development will assist us in understanding tooth anomalies: (1) Teeth form from the cooperative interaction of two germ layers: ectoderm and ectomesenchyme (2) Enamel is formed from the ectodermal components. (3) Dentin, pulp, cementum, the supporting PDL, and bone are all derived from ectomesenchyme.

Introduction Very few heritable dental traits are truly Mendelian. Most dental variations are polygenic, that is controlled by several genes. With these, we often speak of the degree of expression or penetrance. Individually, anomalies are rare but collectively they form a body of knowledge with which all dentists should be familiar.

Eruptional problems Ectopic Eruption is a developmental disturbance in the eruption of the permanent dentition (in direction). The affected tooth is out of normal alignment and causes sometimes abnormal resorption of another neighboring primary/permanent tooth ( undermining resorption).

Eruptional problems The most commonly ectopic erupted teeth are: Permanent maxillary first molars Maxillary canines Permanent mandibular lateral incisors.

Eruptional problems Ectopic erupted lower centrals Ectopic erupted upper molar

Eruptional problems Ectopic erupted upper centrals, labially

Impacted teeth are those that have failed to erupt and remain buried in the alveolar bone. Usually, some barrier to eruption will be seen on the X-ray film. The third molars and maxillary canine are the most frequently impacted teeth, followed by premolars and supernumerary teeth. Eruptional problems

Impacted second premolar Impacted second molar

Eruptional problems Upper central palatally impacted Impaction of upper canine

Anomalies in Tooth Eruption An iatrogenic disease or condition is one that is 'doctor- caused'. If a second molar is inadvertently impacted by a poorly placed molar band, it is an iatrogenic cause for impaction.

Anomalies in Tooth Eruption Treatment of ectopic eruption: Self-corrective: 66% of the ectopically erupted molars finally erupted into an acceptable position without corrective treatment (Young, 1957). Treatment with eruptive guidance (ortho): After Extraction of the primary second molar; the permanent molar is allowed to erupt and then distalized to a normal position.

Hyperdontia Hypodontian Anomalies in Number of Teeth

Hyperdontia (or supernumerary teeth ) is defined as an increase in the number of teeth in a given individual, i.e., more than 20 deciduous teeth, and over 32 teeth in the case of the permanent dentition. Regarding the etiology of supernumerary teeth, most authors point to phylogenetic factors, specifically hyperactivity within the dental lamina, causing the appearance of additional dental buds. Anomalies in Number of Teeth

In addition to those hereditary patterns producing extra or missing teeth, physical disruption of the dental lamina, overactive dental lamina, and failure of dental lamina induction by ectomesenchyme are several examples of etiologic factors that affect tooth number. Supernumerary teeth may occur singly, multiply, unilaterally or bilaterally and in one or both jaws. Rarely it can occur in all the four quadrants of the jawbone. Anomalies in Number of Teeth

Effects of hyperdontia on the developing dentition may be: crowding, delayed eruption of adjacent permanent teeth, displacement and ectopic eruption, formation of diastema, root resorption of adjacent dentition and loss of vitality, dilaceration of adjacent dentition follicular cysts Anomalies in Number of Teeth

Incidence: About 2.0 % in primary dentition About 4.0 % in permanent dentition Males : Females = 2:1 Often in the maxilla (80% -90 %) Most common supernumerary tooth is mesiodens Hyperdontia

In primary Dentition: Most common supernumerary teeth in the primary dentition are upper laterals and canines. Shape is the natural teeth like. Most of them erupt normally. Hyperdontia

In permanent Dentition: 6 -9 time more in the maxilla (incisor and molar region) than in the mandible (premolar region) Most smaller than normal teeth Most irregular shape than normal teeth Hyperdontia

Majority occur with familial instances. About 0.2 % - 1% of all adults 45 – 67 % of all supernumerary teeth Often impacted (75%) are cones shaped have short roots around the midline at the palatal side. Mesiodens

Disto- and paramolars “distomolar” erupt distally to the third molar Small molars distal the third molar (M4 & M5) If localized buccal of the molars, then paramolars Have often 1 root and cones shaped crowns Distomolar or M4

Supplementary PM and canine Supplementary canines always in the maxilla Supplementary premolars always in the mandible Often lingual and about 6-10 years delay of development Often they stay impacted Often traumatic history about the year of age Supplementary PM

Hyperdontia is always associated with: Cleft Lip and Palate Cleidocranial Dysplasia Gardner's Syndrome Down's Syndrome (Trisomy 21) Crouzon's Syndrome (Craniofacial Dysostosis) Hyperdontia

Often supernumerary (deciduous) upper laterals at the affected side. Often hyper- and/ or hypodontia in other regions of the jaw, more in the permanent dentition. Cleft lip and palate

Clinical Features: 1. Hypoplastic or absent clavicles 2. brachycephalic skull 3. Frontal and parietal bossing 4. Hypoplastic mid-face 5. Deafness Cleidocranial Dysplasia

Oral/Facial Features: 1. Supernumerary teeth 2. Delayed exfoliation of primary teeth 3. Delayed/failed eruption of permanent teeth 4. Prognathic mandible 5. High/narrow palatal arch 6. Poorly developed alveolus 7. Roots lacking cellular cementum Cleidocranial Dysplasia

Etiology: Chromosomal aberration - trisomy 21 with 47 chromosomes (95% of cases) Incidence: 1:600 to 1:700 births Clinical Features: 1. Hypotonia 2. Brachycephaly and flat facial profile 3. Short stature and mental deficiency 4. Mongoloid obliquity of palpebral fissures Down's Syndrome (Trisomy 21)

Oral/Facial Features: 1. Hyperdontia (supernumerary teeth) 2. Enamel hypoplasia (peg laterals, microdontia) 3. Macroglossia and decreased salivary flow 4. Hypoplastic maxillary sinuses 5. Small nose with flattened nasal bridge 6. Relative mandibular prognathism 7. Severe destructive periodontitis and low caries rate Down's Syndrome (Trisomy 21)

(Craniofacial Dysostosis) Inheritance: Autosomal dominant Incidence: 1:25,000 Clinical Features: 1. Craniosynostosis (coronal suture) 2. Maxillary hypoplasia 3. Ocular proptosis 4. Conductive hearing deficiency Crouzon's Syndrome

Oral/Facial Features: 1. Mandibular prognathism 2. High arched palate with Cleft in some cases 3. Unilateral or bilateral crossbite and anterior open bite 4. Hyperdontia Crouzon's Syndrome

Oral/Facial Features: 5. Maxillary crowding and ectopic eruption of maxillary first permanent molars (47%) 6. Shovel shaped maxillary incisors Crouzon's Syndrome

Hypodontia (congenital tooth absence): Most common etiology is hereditary Incidence = 0.4 – 0.9 % in primary Dentition Most common: upper lateral incisors Lower incisors Often successor permanent is also missed Hypodontia

Incidence = % in permanent Dentition, excluding third molars Most common: 5 5 > 2 2 > 5 5 > 2 2 About % of 3. Molar are missed. Hypodontia

Hypodontia: the absence of one or a few teeth Oligodontia: Agenesis of numerous teeth Anodontia: Extreme expression of oligodontia, indicating complete absence of teeth Anomalies in Number of Teeth

Hypodontia/ missed 2. PM

Anomalies in Number of Teeth Hypodontia/ missed primary laterals Hypodontia/ missed permanent laterals

Anomalies in Number of Teeth Oligodontia

Syndromes Associated with Hypodontia: Cleft lip and palate Ectodermal Dysplasia Hypodontia

Etiology: Hereditary, majority is x-linked recessive Can also be transmitted as an autosomal dominant or recessive character Incidence: 1:100,000 births Ectodermal Dysplasia Michael Berryman

Clinical Features: 1. Males affected more than females 2. Hypohidrotic type has sparse hair growth 3. Absence of sweat glands 4. Eczematoid reactions of skin Ectodermal Dysplasia

Oral/Facial Features: 1. Hypodontia or anodontia 2. Peg shaped or conical teeth 3. Decreased lower facial height 4. Protruding and everted lips 5. Frontal bossing 6. Depressed nasal bridge Ectodermal Dysplasia

Microdontia (small teeth): Three types of microdontia are recognized: 1. True generalized microdontia - All teeth are normally formed but smaller than normal. 2. Relative generalized microdontia - Normal or slightly smaller teeth present in jaws that are larger than normal. Anomalies in Tooth Size

3. Microdontia - Usually only one tooth is involved. Affects maxillary lateral incisors and third molars. Conditions Associated with Microdontia: Down's Syndrome (peg-shaped laterals) Ectodermal Dysplasia Hemifacial Microsomia (Goldenhar Syndrome) Microdontia

Inheritance: Majority is sporadic but familial instances may occur. Clinical Features: Mental retardation Microcephaly Cranial nerve involvement Facial weakness Hemifacial Microsomia

Oral/Facial Features: 1. Reduced anteroposterior and vertical dimensions on affected side. 2. Marked facial asymmetry apparent with growth 3. Microdontia 4. Delayed tooth development 5. Missing teeth 6. Hypoplasia or aplasia of mandibular ramus or condyle 7. Hypoplasia of palate and tongue on affected side Hemifacial Microsomia

Macrodontia (large teeth): Macrodontia can be classified as three types: 1. True generalized macrodontia - Several teeth are larger than normal. Seen in pituitary gigantism. 2. Relative generalized macrodontia - Teeth are normal or slightly larger than normal in small jaws. 3. Macrodontia of single teeth is relatively uncommon. Anomalies in Tooth Size

Isolated teeth displaying macrodontia can result from twinning abnormalities that originate during the proliferation phase of development. Fusion and gemination are the most common twinning abnormalities, and both demonstrate enlarged crowns. Anomalies in Tooth Size

It is the dentinal union of two embryologically developing teeth. More common in primary dentition Incidence = 0.5% Majority appear as large bifid crown with one pulp chamber Few teeth have two pulp chambers Some authors refer 'syndontism' to fusion. Fusion

Fusion/permanent Fusion/primary

It an incomplete division/twinning of a single tooth bud More common in primary teeth Incidence = 0.5% Bifid crown with single pulp chamber Familial pattern Some writers refer to gemination as 'schizodontism'. Gemination

Fusion can be differentiated from gemination by counting the teeth. The diagnosis can be confirmed as Fusion if there is a reduction in the number of teeth that are present in the dental arch. Gemination versus Fusion

Abnormalities of shape originate during the morphodifferentiation stage of teeth development and are manifested as alterations in crown and root form. Dens Evaginatus (extra cusp) Dens in Dente (also called Dens Invaginatus) Taurodontism Dilaceration Anomalies in Tooth Shape

Occurs due to evagination of inner enamel epithelium Frequency 1-4% Common in central groove of posterior teeth or cingulum of anterior teeth The Carabelli Cusp Talon cusp in incisors Dens Evaginatus

The most common extra cusp is the Carabelli Cusp which is found on the mesiolingual cusp of maxillary first molars AND maxillary second deciduous molars. Carabelli cusp

A talon cusp is an extra cusp that resembles an eagle's talon (a talon is the claw of a bird of prey). A talon cusp appears as a projection from the cingulum of incisor teeth. These can interfere with occlusion; however, grinding them down is a hazardous endeavor. Talon cusps often contain enamel, dentin and a prominent pulp horn which is very susceptible to exposure in the younger patient. Talon cusp

also called Dens in Dente = tooth within a tooth Occurs due to invagination of inner enamel epithelium Prevalence = 7.7% Maxillary lateral incisors most commonly affected Enamel and dentin can be absent in the invaginated portion leading to pulp exposure Dens Invaginatus

They are Incisors that display enhanced marginal ridges and present with a distinctive shovel-shaped appearance on the lingual aspect. They appear frequently in many persons of Asian origin, including many Native American Indians. They are especially prominent in Eskimo/Inuit who are descendants of Siberians about 4,000 years ago. Shovel shaped incisors

Failure of proper level of horizontal invagination of Hertwig’s epithelial root sheath (bull teeth) Incidence = 0.5 to 5% Teeth with elongated pulp chambers with short stunted roots Conditions with taurodontism: Hypohidrotic Ectodermal Dysplasia Down’s Syndrome Taurodontism

Incidence = 25% in permanent teeth following primary teeth injury Abnormal bend of the root during its development Traumatic etiology, usually to primary teeth Dilaceration

Concrescence Concrescence is a condition of teeth where the cementum overlying the roots of at least two teeth join together.