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:
- precocity:
For temporary teeth, an eruption is considered early when it occurs 1 month (incisors) to 6 months (2nd molars) before the normal eruption date. For permanent teeth, the delay is 1 year. The majority of early eruptions have no significant clinical significance. Teeth present at birth are called vestigial, natal or neonatal teeth and are destined to disappear, otherwise extraction is the rule when the tooth hurts:
- the antagonistic gingiva,
- tongue (Riga-Fede disease) or when mobility may cause fear of inhalation. 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).
- Delayed eruption : may have the following origins:
- 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 many intermediate forms.
b) increase:
- Extra teeth (polyodontics):
– Interested 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 abnormal in shape. Isolated microdontia remains rare. It is sometimes associated with a disorder of pituitary origin. Syndromic forms are more frequent: Down syndrome, Turner syndrome.
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. Relative generalized macrodontia may only be the result of the relative proportions of the teeth and the jaws; heredity plays an important role since it determines the size of the teeth and the size of the jaws separately.
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
2- Gemination:
Dental gemination probably represents an incomplete division of a germ, usually an incisor.
Clinically, the geminate tooth is larger, it has a clear notch on its free edge, with a single root and a single pulp space.
3- Merger :
Occurs when two germs unite through dentin during their formation.
■ This fusion can occur between a normal tooth and a supernumerary tooth or between a normal tooth and its normal neighbor.
■ The roots are separate or partially fused and the pulp cavities are distinct.
4- Concrescence:
It is the union of two germs by the cementum, it is secondary to hypercementosis.
Concrescence most often occurs between the 2nd and 3rd permanent molars and
upper sometimes between a molar and a supernumerary tooth.
Concrescence is to be distinguished from coalescence which is the union of two teeth by a
very dense bone tissue.
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.
the permanent upper lateral incisor is the most involved
7- HUTCHINSON teeth : anomaly stigma of congenital syphilis of which it constitutes an element of the diagnosis.
The anomaly affects the central incisors, their crown has a notch taking the form of a half-moon on the free edge.
their cervical diameter being greater than
that of their incisal edge.
III.4 Structural anomalies: Alteration of the structure of dental tissues
A) structure of enamel:
1- dysplasia/dystrophy/hypoplasia:
Alteration of the structure of dental tissues
Two main families are to be considered:
Dysplasias of genetic origin which are hereditary conditions affecting the enamel or dentin, or both at the same time (amelogenesis, dentinogenesis, odontogenesis imperfecta).
These diseases occur in isolation or accompany systemic diseases and syndromes.
Involvement of siblings or previous generations should be sought to confirm the diagnosis.
Hypoplasia of perinatal or postnatal origin can affect enamel and dentin.
The period is therefore limited to the first years of life, between birth and the 7th year, for permanent teeth.
Hypoplasia may accompany certain general and systemic diseases:
- Gastrointestinal disorders: celiac disease
- Deficiencies
- Nephropathies
- Cyanotic heart disease
- Endocrinopathies: hypothyroidism..
4-1- Amelogenesis imperfecta
-Hereditary amelogenesis imperfecta:
Structural alteration of enamel of embryogenic origin not included in a syndrome (isolated)
Several forms are described:
* The hypoplastic form: reduced thickness of the enamel which appears rough, hollowed out with pits arranged in lines, cups or sheets.
* The 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.
4-2- Dentinogenesis imperfecta (DI):
It is characterized by a qualitative defect in the dentin, which is hypomineralized and very fragile.
The teeth are translucent amber in color, sometimes bluish. The enamel is fragile and easily detaches, hence the intense wear of the teeth.
Dentinogenesis imperfecta affects both temporary and permanent teeth.
-DI TYPE I: it is associated with osteogenesis imperfecta,
Their amber and translucent appearance is striking, as for the coloring, it varies from gray to yellow-brown or purple-brown.
– TYPE II DI: this is the most common and classic of DI, long described under the term “Capdepont disease”.
The enamel is gradually removed, leaving the dentine exposed to saliva, resulting in rapid wear. The damage is often less severe in permanent dentition.
The unsightly, yellow-brown-opalescent appearance is not always found in adult teeth; permanent teeth retaining their enamel then only have gray-blue reflections, mainly at the neck.
The radiological peculiarity that is found in both temporary and permanent dentition is the obliteration of the pulp chamber and canals that occurs quickly after eruption and is the pathognomonic sign of this pathology.
– TYPE III DI: called isolated DI from southern Maryland in the United States, it is characterized by holes in the enamel surface, numerous pulp exposures. On radiographic examination, the teeth have a very large pulp chamber.
4- 3- Dentin dysplasia (DD)
Two forms are described:
- DD type I (rootless teeth): characterized by particularly short (or almost non-existent) and conical roots. The pulp chamber is absent and obliterated by dysplastic dentin.
- DD type II coronary: in this pathology, only the mineralization of the dentin of the temporary teeth is abnormal. The temporary teeth are opalescent with obliterated pulp chambers while the permanent teeth have a normal color with, however, intrapulpal calcifications.
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 pulp mortification. This mortification is secondary to caries, 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.
For some authors, it would be essentially linked to bruxism.
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.
IV.5- Laceration:
It constitutes a particular anomaly of the shape of the permanent upper incisors.
The term has been wrongly extended to abnormal curvatures of all teeth. Laceration occurs when acute mechanical trauma affecting the temporary incisor has adverse effects on the growth of the definitive germ (laceration or tearing of the definitive germ). The trauma must occur around the age of 4 to 5 years, when the crown is formed and the root is still growing. The final horn-shaped coronoradicular curvature is quite particular.
V. Therapeutic possibilities:
Treatment often comes down to tooth extraction, with implantology providing more and more therapeutic solutions.
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, ceramic veneers).
Therapeutics for whitening dyschromic teeth are mostly disappointing.
Dental anomalies.
Impacted wisdom teeth may require surgery.
Zirconia crowns are durable and aesthetic.
Bleeding gums may indicate periodontitis.
Invisible orthodontic treatments are gaining popularity.
Invisible orthodontic treatments are gaining popularity.
Modern dental fillings are both durable and discreet.
Interdental brushes are ideal for narrow spaces.
Good dental hygiene reduces the risk of cardiovascular disease.