Orthodontics
Anomalies
Anomalies
of
Teeth
Groups of teeth
Jaws
Intermaxilary relations
Anomalies of tooth number
 Hypodontics (hypodontia) – the tooth (or teeth)
are missing
Third molars (if third molars are missing –it is not
hypodontia), second premolars, upper lateral
incisors
 Hyperodontics (hyperodontia) supernumerary
teeth
 Anodontics (anodontia)
Anomalies of tooth size
(dimension)
 Microdontics (microdontia) – small teeth, spaces
between teeth
 Macrodontics (macrodontia) – big teeth,
crowding
Anomalies of form of teeth
Dentes confusi - germs of teeth are fused
Dentes concreti - germs of teeth are grown
together at the stage of development of roots
(roots are confused)
Dentes geminati – germ of tooth is grown
together with a germ of supernumerary tooth
Cone teeth
Anomalies of tooth position
 Inclination
 Rotation
 Transposition
 Infraoclusion
 Supraoclusion
 Vestibular, oral eruption
 Diastema
Inclination
 Mesioinclination: the long axix is inclinated
mesially
 Distoinclination: the long axix is inclinated
distally
Inclination
Inclination
Rotation
 The tooth is rotated around the long axis:
Mesiorotation – the vestubilar surface is rotated
mesially
Distorotation – the vestibular surface is rotated
distally
Rotation
mesiorotation
distorotation
Rotation
Vestibular eruption
Supraocclusion
Hypodontia, trema, cone tooth
Protrusion
Tremata
Transposition 13,14
Anodontia 22, persistency 62
Distoinclination 21, 22,
infraocclusion 23
Anomalies of group of teeth
 Compression
 Nonocclusion
 Deep bite
 Open bite
 Retrusion
 Protrusion
 Inverse bite
 Prognatism - overlap
Key of occlusion acc. to Angle
 Normoocclusion:
Mesiobuccal cusp of the first maxillary molar goes
between mesial cusps of the first mandibular
molar.
Key of occlusion acc. to Angle
 Normoocclusion (normoocclusia)
 Distoocclusion – mandible is in posterior
position (distoocclusia)
 Mesiooclussion – mandible is in anterior
position (mesioocclusia)
Classification acc. to Angle
Angle
Class I
Class I
The mesiobuccal cusp of the maxillary first molar lies in the mesiobuccal
groove of the mandibular first molar,
but the other teeth may have other anomalies such as spacing,
crowding, open bite etc.
Angle
 Class II
 Is also called distocclusion, or mandibular retrognathism
 The mesiobuccal cusp of the upper molar is situated anterior to the
mesiobuccal groove
 Two subdivisions exist:
 Division 1 (II/1) --> Anterior teeth protrude, increased overjet
 Class II/1
Class II/1 Class II/2
 Class III
 Is also called Mandibular Prognathism
 The mesiobuccal cusp of the upper molar lies
posteriorly to the mesiobuccal groove of the
first mandibular molar
Class III
Mandibular prognatism, inverted
bite, infraocclusion, crowding,
open bite
Deep bite
Overjet
 Is the distance between the tip of the upper and the tip of
the lower incisors in the horizontal plane
 The normal distance is ~ 1.5-2.5 mm
 We distinguish two types of overjet:
 Positive overjet --> Distance >2.5 mm
 Negative overjet (anterior cross bite) --> Distance <1.5
mm
Overbite
 Normally the upper centrals should cover
between 1/3 - 1/4 of the anterior surface of the
lower centrals
 Any disturbance in this coverage can result in:
 Open Bite
 Deep Bite
Scissor Bite
 Is a rather rare orthodontic malocclusion, where
the palatal surface of the upper molars rest
laterally from the buccal surface of the
mandibular molars
Midline Deviation
 Occurs when the midline of the upper jaw
doesn't coincide with that of the lower jaw
Posterior Cross Bite
 In this malocclusion the buccal cusps of the
upper molars lie in the opposing central fossa of
the mandibular molars (in physiological
conditions the palatal cusps of the upper
molars lie in the opposing central fossa)
Mesioocclusion, posterior cross
bite
 Crowding
Is the result of lack of space in the dental arch
 Spacing
Is the result of excess of space in the dental arch
 Wide interdental spaces
Diastema
Space between the two central incisors
 Rotation
 The tooth is rotated in the longitudinal axis
Diastema
Reasons
 Genetic factors
 Loss of primary teeth
 Persistency of primary teeth
 Insufficient function of masticatory apparatus
 Mouth breathing
 Parafunctions (sucking of thumb, dummy, put
the lip between teeth etc.)
Prevention
 Natural food admission (nursing, later chewing)
 Care for primary dentition
 Avoid parafunction
Therapy
Orthodonric appliances
 Passive (functional – always removable)
Enable the change of position of jaws and teeth
trough the function.
 Active
Affect active forces on teeth (removable, fixed)
 Removable – desk appliances (active
components- e.g. screws)
 Fixed (brackets, wire)
wire bracket ring
elastic pull