Dental anomalies
I / Introduction:
Dental anomalies, like those of all organs, obey the laws of general pathology. They are classified into 3 categories:
– Congenital anomalies: contracted in utero
– Hereditary anomalies: transmitted genetically
– Acquired anomalies: appear after birth
II / Etiologies:
Several theories to explain the different dental anomalies:
- Genetic theory: chromosomal alterations;
- environmental factors during embryogenesis
- Direct trauma to the germ
- Phosphocalcium metabolism disorders
- Avitaminosis (vit D ++ )
- Poisoning: fluoride, medications, etc.
III / Congenital anomalies :
these anomalies are contracted in utero. They can be hereditary or occur following a genetic mutation.
III.1 Eruption anomalies:
1- precocity:
– vestigial teeth destined to disappear
– premature eruption may accompany certain syndromes
Ex: Sotos syndrome (brain gigantism: rapid growth)
Ellis Van Creveld syndrome (chondroectodermal dysplasia: polydactyly, cleft lip and palate, dwarfism, etc.)
Sturge-Weber syndrome (encephalotrigeminal angiomatosis).
2- Delayed eruption:
may have as origin:
- Local obstacle: tumor, odontoma, etc.
- Endocrine disorders: hypogonadism, hypothyroidism, hypopituitarism…
- Genetic origin: syndrome. Ex: picnodysostosis.
3- Exfoliation:
It is the premature expulsion of temporary and/or permanent teeth which can accompany different diseases which have in common periodontal and bone lysis
Ex: – hypophosphatasia (congenital deficiency of alkaline phosphatase)
– Langerhans histiocytosis
– Chediak Higashi disease
– Papillon-Léage syndrome.
III.2 Number anomalies:
a) Reduction:
1- agenesis : this is the absence of a tooth and its germ
*Anodontia = absence of all primary or permanent teeth
*Oligodontia: partial anodontia extending to one or two maxillae.
2 – Syndromic forms:
Syndromic oligodontia is involved in many polymalformative syndromes.
Example: Anhydrotic (or hypohydrotic) ectodermal dysplasia or Christ-Siemens-Touraine syndrome: characterized by hypodontia or total anodontia + anhydrosis (no sweating) and hypotrichosis (hairless) in a subject with an infantile or senile appearance. There are numerous intermediate forms.
b) Increase:
- Extra teeth (polyodontics):
– Interesting in temporary and permanent teeth
– Predominate in the upper incisor and premolar region
– Can be conoid or normal
– Are isolated or associated with other malformations.
- Incisor hyperodontia ( mesiodens ):
A supernumerary tooth of conoid shape, in normal or anastrophic position (180° version around the horizontal axis) between 11 and 21.
- Odontome/odontoid: this is a more or less well calcified dental outline.
III.3 Form anomalies:
a) Size anomalies:
1- Microdontia (dental dwarfism):
This is the reduction in the size of the teeth. The involvement of the entire dentition is rare and is accompanied by interdental diastemas. These teeth are of poor quality and often of abnormal shape.
2- Macrodontia (dental gigantism):
It is the increase in the size of the teeth. The insufficient space caused on the arch leads to dental overlaps.
b) morphological anomalies:
1-Carabelli tubercle and Bolk tubercle:
* T.de Carabelli: supernumerary cusp on the palatine face of 16/26
* T.de Bolk: supernumerary cusp located on the vestibular surface of the upper molars
- Gemination:
The dental element appears to consist of several teeth.
Common anomaly at the level of the upper incisors. The union occurs during fusion, but between a normal tooth and a supernumerary tooth (affects the crown or the root or both at the same time.
3- Fusion:
Occurs when two germs unite through dentin during their formation.
4- Concrescence:
It is the union of two germs by the cementum, it is secondary to hypercementosis.
5- Taurodontism:
Anomaly of radiological discovery by the presence of a large pulp chamber.
6- Dens in teeth :
It is the invagination of the enamel into the pulp.
III.4 Structural anomalies: Alteration of the structure of dental tissues
A) structure of enamel:
1- dysplasia/dystrophy: This term would be appropriate for all enamel lesions which are due to a disturbance of amelogenesis without any genetic etiology.
2- Amelogenesis imperfecta:
- Hereditary amelogenesis imperfecta:
Structural alteration of enamel of embryogenic origin not included in a syndrome (isolated)
Several forms are described:
* hypoplastic form: reduced thickness of the enamel which appears rough, hollowed out with pits arranged in lines, cups or sheets
*hypomature form: opaque or pigmented (orange) enamel, quickly abraded
*hypocalcified form: enamel of normal thickness but soft and crumbly
- Syndromic amelogenesis imperfecta:
It accompanies many genetic conditions.
The hypocalcified form is observed during metabolic diseases (rickets, Albright’s disease, etc.) and ectodermal disorders (occulo-dento-osseous syndrome, epidermolysis bullosa, etc.). Other forms (hypomature, hypoplastic) can also be encountered.
B) Structure of dentin:
1- Dentinogenesis imperfecta (DI): The teeth are translucent amber and sometimes bluish in color. The enamel is fragile and easily detaches, leading to intense wear of the teeth.
- Hereditary opalescent dentin represents the isolated hereditary form of dentinogenesis imperfecta.
- Familial Capdepont dysplasia is a genetically transmitted form affecting both sets of teeth (temporary and permanent), associating other dental anomalies (position, number, etc.)
2- Dentin dysplasia (DD): Two forms are described:
- Coronal DD: damage to the crown of baby teeth which appear translucent with anarchic histological structure of the dentin.
- DD root: the crown is normal but the root is short giving the appearance of a tooth without a root. The pulp chamber is absent.
III.5 Position anomalies:
A – Dental inclusion
The radiologically existing tooth does not erupt on the expected date.
B- Ectopy:
The tooth is located at a distance from its usual place of eruption.
C- Heterotopia:
The tooth is located in an extramaxillary position.
D- transposition:
The tooth has swapped places with an adjacent tooth. The case of the canine and the premolar is common.
E- rotation:
The vestibular surface of the tooth is oriented towards the lingual side.
IV/ Acquired anomalies:
IV.1. Dyschromia:
1- By pulp mortification:
The tooth becomes grayish due to the mortification of the pulp. This mortification is secondary to a cavity, direct trauma or repeated microtrauma (bruxomania)
It is also secondary to therapeutics (devitalization, sinus curettage with lesion of the vasculo-nervous bundle of the M and PM).
2-Post medication:
Poisoning by certain substances such as mercury and cadmium can cause dyschromia.
Likewise for certain drugs such as cyclines: (tetracycline, doxycycline) taken during pregnancy or during organogenesis give very unsightly yellowish or grayish colorations.
3- Fluorosis or human Darmous:
It is fluoride poisoning.
It manifests as yellow then brownish spots at the vestibular lingual level of the teeth. The incisors and the 6 are the first to be affected.
4- Neonatal jaundice:
Green pigmentation secondary to neonatal jaundice.
5- Leukomas:
Coronal whitish spots.
IV.2. Mylolysis or wedge-shaped resorptions:
Axe-shaped, with a smooth and shiny surface, located at the dental necks on the vestibular surface.
Often sensitive to microtraumas: (brushing, sugar).
They sometimes require devitalization (slow pulp mortification). They can also stop spontaneously.
IV.3. Rhizalysis
1) Physiological rhizalysis on temporary teeth: leaves only the crown, leading to its fall.
2) Rhizalysis on permanent teeth:
It translates into pulp mortification:
- when the tooth is reimplanted
- in contact with an included tooth
- near an intra-osseous tumor…
IV.4. Abrasions:
This is abnormal, horizontal wear of the tooth which is particularly brittle.
The origin is mechanical (bruxomania). A reactive pulp calcification occurs gradually.
V/ Therapeutic possibilities:
Treatment often consists of tooth extraction.
When the crown height and the condition of the root allow it, we can consider prosthetic restorations (crowns, bridges, etc.) or restorations with aesthetic materials (composites).
Therapeutics for whitening dyschromic teeth are mostly disappointing.
Dental anomalies
Early cavities in children need to be treated promptly.
Dental veneers cover imperfections such as stains or cracks.
Misaligned teeth can cause difficulty chewing.
Dental implants provide a stable solution to replace missing teeth.
Antiseptic mouthwashes reduce bacteria that cause bad breath.
Decayed baby teeth can affect the health of permanent teeth.
A soft-bristled toothbrush preserves enamel and gums.