Development of tooth is a continuous process which
undergoes several morphologic stages.Erupted or impacted as in case of
mesiodens
Supplemental teeth like
paramolars, distomolars
Treatment Rehabilitation with complete dentures
or implant supported prostheses
Orthodontic space closure /
rehabilitation with fixed or
removable partial dentures/
implants
Surgical removal of supplemental
teeth in case of crowding,
impaction, infection, etcTable 6.1: Commonly occurring disturbances in alterations in number of teeth
Anodontia Hypodontia Oligodontia
Definition Total lack of teeth of one or both
dentition
Developmental absence of
multiple teeth
Excess number of teeth
Etiology Hereditary, frequently associated with
hereditary ectodermal dysplasia
 Autosomal dominant with
incomplete penetrance, trauma,
infections, radiation overdose,
glandular dysfunction, systemic
conditions like rickets, rubeola
during pregnancy
Recessive, autosomal or sex-linked, continued activity of dental
lamina even after formation of
normal number of tooth series or
complete division of developing
tooth buds
Clinical features
 Absence of appropriate/sufficient
segments of dental lamina
Total absence of teeth Missing teeth: Primary,
permanent and other
abnormalities like fusion,
ankylosis, short roots
Rudimentary or may be of normal
size.Disturbances in size, shape, number, position, and
structure of teeth may be due to disturbances in corres-ponding stages/physiologic phases of tooth development,
being initiation, proliferation, histodifferentiation,
morphodifferentiation, apposition phases.Second most common is maxillary fourth molar, and
other teeth with some frequency are maxillary paramolars,
mandibular premolars, and maxillary lateral incisors.SUPERNUMERARY TEETH
Etiology
May develop from third tooth bud arising from dental
lamina near permanent tooth bud or possibly from
splitting of permanent bud itself.It arises from an attempt at division of single tooth
germ by invagination with resultant incomplete
formation of two teeth.Commonly occurring developmental disturbances are
discussed in Table 6.1.Most common is 'Mesiodens', situated
between maxillary central incisors.