Dental Anomalies: Number, Size, and Shape

• Dental anomalies may be classified into categories such as:

• Alterations in the number of teeth

• Alterations in the size of teeth

• Alterations in the shape of teeth

• Alterations in the position of teeth

• Abnormalities of the dental pulp

• Abnormalities in tooth structure

• It is important to identify abnormalities and deviations clinically and radiographically.

• It is important to understand treatment options for patients with dental anomalies.

• It is important to be able to refer patients appropriately for management.

• Common causes of dental anomalies are the formation of the tooth germ, disruption to the tooth germ, and eruption.

Alterations in tooth number

• Hypodontia is when there are not enough teeth.
• Anodontia is when there are no teeth.
• Both hypodontia and anodontia are linked to genetics and may be linked to syndromes.
• Hyperdontia/supernumerary describes more teeth than normal.
• Supplemental teeth
• Mesiodens teeth
• Tuberculate teeth
• Conical teeth

Alterations in size

• Macrodontia refers to larger than normal teeth.
• Microdontia refers to smaller than normal teeth, and can be generalised or localised.

Alterations in shape

• Concrescence is when teeth are fused together by cementum.
• Fusion is the joining of two developing tooth germs.
• Gemination is when a single tooth germ attempts to divide, resulting in a large, bifid crown.
• Dens in dente (Dens invaginatus) is a tooth within a tooth.
• Dens evaginatus is an accessory cusp-like elevation of enamel.
• Talon cusps are extra cusps on the lingual or facial surfaces of anterior teeth.
• Taurodontism is the enlargement of the body and pulp chamber of a multirooted tooth with apical displacement of the pulpal floor and bifurcation of the roots.
• Hypercementosis is the excessive deposition of cementum on the root surface.
• Dilaceration is an abnormal bend or curve in the root or crown of a tooth.
• Enamel pearls are small masses of enamel on the root surface of a tooth.

Abnormalities of the dental pulp

• Resorption is the loss of tooth structure.
• Resorption may be internal/external
• Physiologic
• Idiopathic
• Pathologic
• Pulp Calcification is the formation of calcified masses within the dental pulp.
• Pulp stones are calcified masses within the dental pulp.
• Secondary/reparative dentine is the dentine formed in response to injury or irritation.
• Pulp obliteration is the complete closure of the pulp chamber and/or root canal.

Abnormalities in tooth position

• Submerged teeth are teeth that have become fused to bone.
• Impacted teeth are teeth that are blocked in their eruption.
• Transposed teeth is where the position of two teeth are swapped.
• Ankylosed teeth are fused to the alveolar bone, preventing exfoliation and eruption.

Abnormalities in tooth structure

• Hypoplasia is deficient enamel formation.
• Molar incisal hypoplasia affects the molars and incisors.
• Hypomineralisation is deficient mineral content in enamel.
• Turner tooth is the hypoplasia of a permanent tooth as a result of infection or trauma to its deciduous predecessor.
• Dentinogenesis Imperfecta
• Type I, II and III
• Amelogenesis Imperfecta
• Hypoplastic AI, hypocalcified AI, hypomaturation Al, hypomaturation-hypoplasia Al
• Staining
• Tetracycline staining

Management of dental anomalies

• Management should be considered on a case-by-case basis.
• Doing nothing and reviewing is an option if there is no aesthetic concern.
• Specialist referral is an option for complicated conditions.
• Restoration is an option for conditions manageable in primary care.
• If in doubt, get a second opinion.